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SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au Contents Vol.18, No.11; November 2005 www.siliconchip.com.au FEATURES    8 Broadband Over Power Lines: A Flawed Technology Broadband Over Power Lines could be coming to a pole near you. It’s currently on trial in Tasmania and not everyone’s happy – by Ross Tester 12 Car Sound On The Cheap; Pt.1 You can put together a good in-car sound system for just $200-300. Here’s how to go about it – by Julian Edgar Good Quality Car Sound On The Cheap – Page 12. 18 Microbric: Robotics For Everyone! Microbric is about to hit the Australian market with major press campaigns. Here’s a sneak preview – by Ross Tester 90 PICAXE In Schools; Pt.5 Final instalment shows you how to add IR remote control and voice recording to your PICAXE – by Clive Seager PROJECTS TO BUILD 26 Studio Series Stereo Headphone Amplifier Looking for a top-class headphone amplifier? This superb unit is easy to build and can drive both high and low-impedance ’phones to full power with very low noise and distortion – by Peter Smith 36 Build A MIDI Drum Kit Stereo Headphone Amplifier – Page 26. This do-it-yourself MIDI drum kit can produce just about any musical sound you can think of, either via a computer or a synthesiser – by John Clarke 70 Serial I/O Controller & Analog Sampler It connects to your PC’s serial port and can switch relays according to voltage, resistance, temperature and digital inputs. It also includes system timers and can be operated as a PLC-style controller – by Trent Jackson 80 Delta XL02 Tower Loudspeaker System A high-power 2-way system that you build from a kit – by Leo Simpson SPECIAL COLUMNS 65 Serviceman’s Log The fountain of all knowledge – by the TV Serviceman 86 Circuit Notebook Serial I/O Controller & Sampler – Page 70. (1) 1W LED Driver Circuit; (2) Simple Cable RJ-45 Cable Tester; (3) Improved LED Torch; (4) Load Sharing Multiple Supplies; (5) Paraphase Tone Control 96 Salvage It! Scrounging and (gulp) buying the bits – by Julian Edgar 102 Vintage Radio Vintage radio clubs: 15 years old and going strong – by Rodney Champness DEPARTMENTS   2   4 48 99 Publisher’s Letter Mailbag Order Form Product Showcase siliconchip.com.au 106 108 109 111 Ask Silicon Chip Notes & Errata Market Centre Ad Index Delta XL02 Tower Loudspeaker System – Page 80. November 2005  1 SILICON CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Editor Peter Smith Technical Staff John Clarke, B.E.(Elec.) Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Reader Services Ann Jenkinson Advertising Enquiries Lawrence Smith Benedictus Smith Pty Ltd Phone (02) 9211 8035 Fax: (02) 9211 0068 lawrence<at>benedictus-smith.com Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Julian Edgar, Dip.T.(Sec.), B.Ed, Grad.Dip.Jnl Mike Sheriff, B.Sc, VK2YFK Stan Swan SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490 All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Hannanprint, Noble Park, Victoria. Distribution: Network Distribution Company. Subscription rates: $83.00 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial office: Unit 8, 101 Darley St, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9979 5644. Fax (02) 9979 6503. E-mail: silchip<at>siliconchip.com.au Publisher’s Letter Broadband over Power Lines will blot out many radio services Our story this month about trials of Broadband over Power Lines (BPL) should give everyone cause for concern. While low-cost universal broadband internet access is a desirable facility for virtually everyone these days, it should not come at the cost of conventional radio services. Just imagine every street in every major city and town in Australia blanketed with BPL signals ranging from just above the AM broadcast band to just below the FM band – almost 80MHz of bandwidth. This will play merry hell with all the radio (and TV) services in that range. In fact, it would mean the end of any useful radio services in that range. You can forget any 27MHz CB radio, radio control, all shortwave radio, emergency services, amateur radio, business radio, analog cordless phones and virtually anything else which might be in that 80MHz bandspread. So why have trials been authorised, both here and overseas? Good question. The answer must be that the relevant energy authorities have lobbied very hard to be able to use their vast wire grids for something else besides just carrying electricity. Even so, it is incredible that the trials have even started, let alone be permitted in the first place. It makes a huge mockery of all the EMC compliance regulations that all electronic equipment must now meet. Why have EMC compliance when the power authorities will be able to blast interference out to everyone, completely unfettered by past regulations? It just beggars the imagination! I must sheepishly admit that when BPL was first mooted several years ago, I wondered how they would do it. I idly thought that they would probably send the signals via optical fibres down the inside of the power cables. After all, existing high voltage transmission lines use a steel core with an aluminium sheath – the steel core provides the tensile strength while the aluminium provides the conductivity. So it would not be a huge step to put optical fibres inside power cables. It just did not occur to me that BPL would involve feeding the signal directly onto power wires – after all, that would radiate like crazy, wouldn’t it? Well, silly me. There never was any intention of modifying all the power cables to take optical fibres. How naive of me! I just did not think it through. And the people who authorised BPL trials have not thought it through either. BPL in its present form is a very bad idea. It might initially appeal to the non-technical populace but when the true ramifications take hold, there will be hell to pay! Leo Simpson ISSN 1030-2662 * Recommended and maximum price only. 2  Silicon Chip siliconchip.com.au Innovative • Unique • Interesting • Hard to find products Video Capture Captures from digital & analogue camcorders plus VCR/TV/DVD. Comes with handy front-access connections. Cat 23027-7 $299 Removable HD Kit VGA Extender Cordless Skype & Standard Phone Extend VGA up to 130m over inexpensive STP cable. Cat 3441-7 $399 An aluminium frame and tray to convert any standard IDE HD into a removable backup/storage device. Also available for SATA drives. Cat 6802-7 $79 Make & receive normal voice calls and calls over the Skype network with this cordless phone. Up to three additional handsets can be used with the main unit. Cable Tracer Extend USB 50m Cat 10172-7 Dualphone $212.50 Features a single or Use inexpensive network Cat 10173-7 Extra Handset $107 multi-tone signal. Comes cable (not included) to with two test leads and extend any USB 1.1 Windows a 4-conductor modular device up to 50m from a cable. PC. Based Cat 11520-7 $129 Cat 11666-7 $99 Terminal This tiny WBT can attach to the VESA mounts on a LCD monitor. It supports RDP and emulates SCO, DEC, Wyse etc. Cat 1239-7 $649 KVM Switches Control Multiple PCs with one console (keyboard, mouse and monitor). Cat 11654-7 Two Way $79 Cat 11655-7 Four Way $129 Cat 11656-7 Eight Way $449 Cat 11657-7 Sixteen Way $799 Cordless Bluetooth Barcode Scanner High Power Bluetooth Dongle What’s New? USB Copy Box • Lets you copy data from one USB device to another, without the need for a computer. • Simply choose your source and destination and start copying. • Ideal for transferring music, software, pictures and general data. Cat 3574-7 $79 12v Mini PC A tiny barebones PC that is perfect for the boat, car, or any space critical situation. Based on the VIA Eden 833Mhz processor and motherboard, it can operate on 12v or 240v making it ideal for use in boats or cars. The case measures only 49 x 220 x 165mm. It can take a 2.5" laptop hd or CF card, other devices such as a CDROM can be attached via USB. The integrated motherboard includes VGA and LAN. Cat 1167-7 $750 Ipod/MP3 Car DJ Plug a USB flash drive, iPod or MP3 player (or any audio source with an audio output like your PDA or CD player) into the MP3 DJ FM Transmitter, tune into the specified FM channel and you can listen to your favourite digital music over your car stereo. Cat 3570-7 $69 Hard Disk Restore Card USB to Serial Plugs into a USB port A high power Bluetooth and can provide multiple dongle with a nominal serial ports. range of 100m. Compliant Cat 2828-7 One port $54 with Bluetooth v1.1 Cat 2852-7 2 port $119 Cat 11904-7 $89 Cat 2851-7 4 port $349 7 Port USB 2.0 Hub Attach up to seven USB devices to the one USB port with this powered hub. Cat 2904-7 $77 PCMCIA to Serial Add two serial ports to your notebook. Cat 2726-7 $269 Restore the PC hard disk to its previous state on restart. Perfect for Internet cafes, schools, etc. Cat 17079-7 $74 • Normally delivered next day • Not sure what product you require? Call us for friendly advice! RFID Controller Suitable for RFID security applications. RFID readers, electronic door This cordless CCD scanner uses Bluetooth locks, alarms, can all be technology for reliable & accurate perattached to this unit. formance. Comes with Bluetooth dongle. Cat 1008079-7 $179 Requires AA batteries (not included) Cat 1008178-7 $799 ask<at>mgram.com.au Cordless Mini Keyboard A black 88key keyboard that includes a pointing device. Great for when space is an issue. Cat 8750-7 $179 02 4389 8444 www.mgram.com.au SATA Controller Add two SATA connectors to your PC with this handy PCI card. Cat 2872-7 $79 Macro Stick Easily web-enable your serial devices. Allows RS232/422/485 devices, including modems to be used over a TCP/IP network. Cat 15141-7 $259 Receipt Printer A 42 column dot-matrix receipt printer. Great for entry level POS applications. Cat 5849-7 $499 USB Auto-Reset If a computer stops responding this USB device applies a hardware reset to the computer. Great for remote computers with no operators. Cat 17084-7 $169 PCMCIA slot for PC Simply plug this PCI card into a PC to access Type I, II and III PCMCIA Cards. Cat 6539-7 $69 Digital I/O Card A PCI card that provides 48 digital I/O lines and three 16bit counters with a maximum count rate of 10MHz. Cat 17053-7 $249 Dealer Phone: 02 4389 8444 inquiries FreeFax: 1800 625 777 welcome ask<at>mgram.com.au siliconchip.com.au www.mgram.com.au ovember All prices subject to change without notice. For current pricing visit our website. Pictures are indicative N only. 2005  3 SHORE AD/MGRM1105 Serial to Ethernet 16 programmable keys that store up to 1000 keystrokes. Designed to sit above the function keys on a standard keyboard. Cat 15131-7 $299 MAILBAG Skype can have a costly drawback I’d like to make a comment regarding Skype, as mentioned in your VoIP article in the September 2005 issue. As a long-time professional and audiophile, I have been bemused by the apparent acceptance of P2P (peerto-peer) technology. I have also been amused (constantly) by the number of friends and acquaintances who get into never-ending trouble by their unthinking use of such technologies. Spam, spyware, malware, call it what you like, if there’s one sure way of opening up your computer to anyone at all, it’s by installing P2P applications. Having said that, I was keen to become involved with VoIP some months ago. I installed Skype and have been using it for many months. Now for the bad bit. As I’m connected via Optusnet cable broadband, I’ve always had a good quality firewall solution installed. A few weeks ago, I started noticing a fairly significant increase in my usage but thought nothing of it until my Optusnet “unlimited” account usage went into speed limitation (22kB per second throughput). After checking my data with network analysers, verifying firewall settings and so on, I found that Skype had been going berserk in terms of IP port usage and data throughput. Since the start of October, I’ve logged over 2GB throughput in three days. After some head-scratching and in-depth discussion with my networking mate, we “discovered” that my system, as part of the Skype P2P network, is currently hosting more than 300 individual concurrent Skype conversations. The peak so far is 621 conversations, the average per 24-hour period is 180 conversations. The Skype official response to my enquiry is “well, that’s what a peerto-peer network does!”. I forgot that this is the same mob that wrote Kazaa. Since I have no option of redress and since Skype (and I have now learned, all other VoIP P2P applications) have no plans for allowing a sucker – sorry, user – like myself to limit the number 4  Silicon Chip of Skype hosting sessions on my machine, I have no option but to remove Skype and lose all the benefits of such an application. I know, I know, it’s P2P and I should expect some pain with the gain. But not a 700MB per day penalty. After all, I’m paying more for other people’s conversations than I ever use! I thought you might like to be aware of the pitfalls of VoIP and that your less network-savvy readers might benefit from understanding the limitations of this “free” technology. There are VoIP tools available that work just fine if you know the other party’s IP address and with most ISPs providing good DHCP leases for always-on systems like mine, this might be a viable and useful alternative. Perhaps you guys could investigate this side of VoIP in a future article. Peter Naus, Mitcham, Vic. Valve amplifiers not as good as solid-state While reading your August issue I could not contain myself any more. Are valve amplifiers better than solid-state amplifiers? In my opinion, no. Was the development work of solid-state power amplifiers, by such eminent design engineers as H. C. Lin, Dr A. R. Bailey, P. J. Baxandall, M. J. Otala, W. G. Jung and J. L. Linsley Hood all in vain? The term “High Fidelity” (not hifi) meant what it said: “reproduction as true to the original sound as possible”. My first power amplifiers were valve and had output powers of 8-10W RMS. The benchmark then was the 15W valve design by D. T. N. Williamson, 1947. In all valve designs, the quality of the output transformer was the main component in achieving this benchmark. Speaker systems were usually 15W in large boxes and as efficient as possible. This current valve design doesn’t meet the Williamson benchmark, although no-doubt a fine amplifier. I made a number of early semiconductor amplifiers with transformer- coupled germanium power transistors, none of which performed as well as my DIY valve amplifier. Then in April 1969, J. Linsley Hood (JLH) published his 10W class-A amplifier in Wireless World. After building and testing this amplifier, I found it to be superior to my valve and semiconductor units. This amplifier had only four transistors per channel! To this day, there is still an internet site just devoted to the JLH Class-A amplifier, with improvements, testimonials and updates. www.tcaas. btinternet.co.uk/index.htm Exponents of valve amplifiers use such emotive (non-technical) terms as warmth, sweet, soft on the ear, etc and are really referring to the lack of uneven harmonics (mainly 3rd) and introduced inductive/capacitive effects and thermionic noise from the valves. Having lived and worked in London, I used to go to concerts in the Royal Festival and the Queen Elizabeth II Halls. The acoustics in these halls and the Sydney Opera House are superb. This was a great way to hear a musical standard that is difficult reproduce. A home reproduction system would have to reproduce these concerts with their dynamic and transient range as near as possible. A modern welldesigned semiconductor amplifier will add very little colour (if any) in reproducing sound from recordings. I can not say that of valve amplifiers. Also, the mutual conductance of the valves drops in time due to cathode depletion or they become gaseous and some produce microphonic noise or clicks and pops, etc. Is a 1955 Silver Cloud Rolls Royce as good as a 2005 Holden or Ford? Take siliconchip.com.au them up a country road for a test run. While the modern cars do better, one still has to admire the Rolls as a thing of beauty. Chris Baker, Dungog, NSW. twin motor-cycle is very pleasing to the ear for some. The same can be said for valve amplifiers. Greg Johnson, Cooma, NSW. Games port solution for PowerUp Power supply capacitors still a problem I have read the feedback on your USB PowerUP project (SILICON CHIP, November 2004), regarding modern motherboards which have the USB ports permanently powered. However, every modern motherboard I have checked does not leave the 5V on the 15-pin joystick connector when it is powered down. I have used this source of power on three PCs at home, to switch the screens, printers, speakers, etc off. I solder male and female DB15 sockets back to back, then a short length of figure-8 wire to the +5V and ground pins, the other end of which I solder to a female PS2 line socket (available from Jaycar). The figure-8 wire is wrapped around the DB15 pins a couple of times so they cannot be broken off, then electrician’s tape wrapped around it a few times, with the wire coming out at one side. The arrangement works well and leaves the joystick port available for use if required. The arrangement could be applied to the PowerUp project. John Bagster, Hamilton, Qld. Valve amplifiers like old Harleys First of all, congratulations on a first-class publication. You have proved your versatility once again by “biting the bullet” and publishing the valve amplifier project in August and September. This amplifier certainly is innovative with its output configuration and the large monetary saving on output transformers which will make it desirable in many hobbyists’ eyes. While valve amplifiers may or may not be everybody’s cup of tea and some may even consider it a waste of time, many still like valve sound, similar to many people liking old Fords, Holdens or Harleys. They may be technically inferior to the high speed, economical modern equivalent but the unmistakable sound of an old V8 sedan or Vsiliconchip.com.au Back in May 2003, you featured an article regarding Taiwan-made motherboard capacitors. This situation has still not gotten any better. We still see computer motherboards on a daily basis afflicted with this problem; always under two years, if the system is always on. While a few manufacturers have switched to Japanese-sourced capacitors, most are just trying different brands of Taiwanese-made units to see whether the problem will go away. Well, I haven’t yet seen a Taiwanese low-ESR capacitor that won’t fail in under two years in an “always on” system. What is worrying is that these capacitors are now finding their way into other items. A friend of mine recently had two very expensive switchmode power supplies blow up right at the 2-year mark. The problem: bulging, leaking Taiwanese-made capacitors. My gigabit network switch just blew up too, again caused by the same capacitor issue. When the capacitors failed, the 12V switchmode supply also failed, taking out the network ports on a couple of motherboards Apart from being out of warranty, the companies won’t even talk to you if you mention that dirty capacitor word. How long before these things get into our expensive fridges, washing machines, vacuum cleaners, cars and airplanes? Ross Peacock, via email. Atmel’s AVR, from JED in Australia JED has designed a range of single board computers and modules as a way of using the AVR without SMT board design The AVR570 module (above) is a way of using an ATmega128 CPU on a user base board without having to lay out the intricate, surface-mounted surrounds of the CPU, and then having to manufacture your board on an SMT robot line. Instead you simply layout a square for four 0.1” spaced socket strips and plug in our pre-tested module. The module has the crystal, resetter, AVR-ISP programming header (and an optional JTAG ICE pad), as well as programming signal switching. For a little extra, we load a DS1305 RTC, crystal and Li battery underneath, which uses SPI and port G. See JED’s www site for a datasheet. AVR573 Single Board Computer This board uses the AVR570 module and adds 20 An./Dig. inputs, 12 FET outputs, LCD/ Kbd, 2xRS232, 1xRS485, 1-Wire, power reg. etc. See www.jedmicro.com.au/avr.htm $330 PC-PROM Programmer This programmer plugs into a PC printer port and reads, writes and edits any 28 or 32-pin PROM. Comes with plug-pack, cable and software. Adaptive cruise control can be uneconomic I read with interest the article on Adaptive Cruise Control Systems in the September 2005 issue. In a “Moffat’s Madhouse” article in the nowdefunct “Electronics Australia”, Tom Moffat saw adaptive cruise control as an example of technology wasting energy. He quoted his experience of driving Also available is a multi-PROM UV eraser with timer, and a 32/32 PLCC converter. JED Microprocessors Pty Ltd 173 Boronia Rd, Boronia, Victoria, 3155 Ph. 03 9762 3588, Fax 03 9762 5499 www.jedmicro.com.au November 2005  5 Mailbag: continued an ageing Volvo between two points trols are much better than others when in USA and attaining a fuel consump- it comes to saving fuel and most recent tion nearly twice that of 100% driver designs would be far superior to that control, by allowing the Volvo’s speed in an old Volvo. For example, a recent long trip in control to maintain a constant speed a current model Honda Accord V6 for the journey. He compared this with the “latest with cruise control returned figures technology” adaptive cruise control of around 7.2l/100km (at constant which accelerates and decelerates the 110km/h and with aircon) – that’s car to follow the driving pattern of the close to 40mpg. It is difficult to see car ahead. Naturally, if the car ahead how driver control could improve on this result. is being driven in an uneconomic way, the adaptive cruise control will The correct way to wire duplicate this driving practice. a 240VAC socket Greg Mayman, I read with interest the letter in the Dover Gardens, SA. Comment: there is little doubt that September 2005 Mailbag from Ray if a car with ACC is driven behind a Smith about 240VAC plug and socket car which keeps fluctuating in speed, wiring. To my knowledge, this is the then it will not be as fuel-efficient as only way to wire them as I was taught it otherwise would be. The only way this in my Electronics Engineering aparound this would be for the driver prenticeship in the early 1980s at the South Brisbane College of TAFE. with ACC to pass. siliconChipAd4 3:52 conpm Page From 1 memory, it was illegal to Fairly obviously, 8/9/05 some cruise wire the plug and socket wrongly as it caused undue strain on the connections and could possibly cause the wiring to come loose. I also believe the teaching was that if the outer sheath was removed by wire cutters or a knife and if the inner wire sheaths were nicked and this wasn’t noticed, it was possible for the leads to come together and short out. Mr Smith has made a valid point and I see some electrical contractors committing the error all the time. Colin Leonelli, via email. Lead acid battery zapper caution I read with interest Jim Rowe’s article on the Lead Acid Battery Zapper. It is certainly an interesting project and the article has an excellent description as to how the lead sulphide crystals reduce the life of the battery. One comment I have is that at the end of the article, Jim very sensibly advised that a choke should be used to protect a battery charger if used in MANUFACTURERS OF LOW POWER RADIO MODULES ESTABLISHED SINCE 1985 The wireless industry's leading product range: • VHF and UHF radio modules on LIPD bands • Single/Multi Channel 25mW version available Transmitters, Receivers • Multi-channel Wide Band FM radio modem and Transceivers • 5 serial select channels on 433.05MHz-434.79MHz band • Narrow Band and Wide Band FM modules • Modulation: 16kbps bi-phase FSK • Serial modem baud rate at 9600bps (halfduplex) • Addressable point-to-point • Data Present indication The TDL2A is a 9600 baud half-duplex OEM radio modem in a BiM2 footprint. Provided no two devices attempt to transmit simultaneously, no further restrictions on data transmission need be made, as all transmit timing, valid data identification and datastream buffering is conducted by the unit. Synchronisation and framing words in the packet prevent the receiver outputting noise in the absence of signal or presence of interference. 6  Silicon Chip • BiM2 footprint 33 x 23 x 7mm • Performs low level packet formatting - preamble, synchronisation, bit balancing, error checking • 32 byte data buffer • Transmit power: +10dBm (10mW) • Receiver sensitivity: -107dBm (for 1% BER) • Supply: 5V <at>28mA transmit, 22mA receive/idle • An interface board (with MAX232 type buffer, 9 way D connector, 5V voltage regulator and SMA RF connector) is available. This board is 61mm x 33mm in size • Encoders and Decoders for RF remote control The TX1H and CVR1 form a miniature VHF radio transmitter and receiver designed for PCB mounting and are suitable for extended range data links at speeds up to 10kbps. Link ranges of 10km + are achievable with suitable choice of data rate and antennas. • Standard frequencies: 151.300MHz, 151.600 MHz,173.225MHz & 173.250MHz • Available on other frequencies from 120MHz to 180MHz • Verified to comply with AS/NZS 4268:2003 • Data rates up to 10kbps TX1H CVR1 • TX1H supply range: 3.8V-15V <at>80mA • Supply: 3V (regulated) <at> 7mA • Transmit power: +20dBm(100mW) nominal • Receiver sensitivity: 120dBm (for 12 dB SINAD) • Supply range: 3.8V - 15V <at>80ma • Feature-rich interface (RSSI, analogue and digital baseband) • Dimensions: 43 x 14.5 x 5mm • Dimensions: 33 x 23 x 8mm • Radio Packet Modems • Radio Packet Controllers • Evaluation Kits RF Modules Australia P.O. Box 1957 Launceston Tasmania 7250 Australia Tel: +61-3-6331-6789 Fax: +61-3-6331-1243 sales<at>rfmodules.com.au Full technical details are available online at: www.radiometrix.com 20 YEARS OF INNOVATION FROM THE PIONEERS IN WIRELESS siliconchip.com.au conjunction with the Zapper. I suggest an even bigger warning should have been added advising that under no circumstances should the Zapper be used on a battery installed in a vehicle, especially one with a computer system. That nice big spike could play havoc with the automotive electronics and probably void the vehicle warranty! John Parncutt, Glen Iris, Vic. Studio 350 Power Amplifier Is A Beauty Talk about a generation gap. The new Tektronix AFG3000 Series signal generators vs. the competition. c 2005 Tektronix, Inc. All rights reserved. Tektronix products are covered by U.S. and foreign patents, issued and pending. TEKTRONIX and the Tektronix logo are registered trademarks of Tektronix, Inc. *Tektronix MSRP subject to change without notice. I thought you might be interested in some pictures of a project a young bloke I know is working on. It is a computer with two Studio 350 power amplifier modules shoehorned in! This forms the heart of a jukebox which he is building himself. He has done the donkey work of fitting the components into the case. I helped build and test the amplifiers and did the mains wiring and power supply wiring. These pictures are of the “working prototype”, as there is still a lot of tidying up of the wiring yet to do and the fitting of various bits and pieces. The biggest concern with the whole concept was whether the amplifier and the computer would have a “happy marriage” together in the one box. Many of his peers, myself as well, said that there quite possibly might be too much noise siliconchip.com.au induced into the amplifier from the motherboard. He was dogmatic that it had to be this way to fit into the jukebox. Well we had the big test and we were all amazed! After the amplifier was tested and adjusted outside the case, we fitted it, powered up and turned on the computer. We were expecting all sorts of noises but apart from a couple of small clicks from the sound card, the amplifier remained silent! So much so that we wondered if it was still working until the jukebox software kicked in. We almost blew the cones out of the speakers! The Studio 350 is an awesome amplifier and we commend SILICON CHIP and those involved with producing such a brilliant design. We were all very impressed! Dave Vieritz, via email. Starting from around $2600+GST. * Unlike the subtle advancements offered in arbitrary/function generators of past decades, our powerful and broad line of arbitrary/function generators delivers serious advantages. The large display confirms your settings at a glance. Sine waveforms reach as high as 240 MHz. You get a front-loading USB port, twochannel capability, and a remarkably intuitive GUI. Visit www.tek.com/generation_gap to see the next generation of signal generation. The Next Generation. http://www.tektronix.com/4130 Enabling Innovation Tektronix Authorized Distributor N e w Tek Instruments Pty Ltd Address: 3 Byfield Street, North Ryde NSW 2113 Telephone: (02)9888-0100 Email: info<at>newtekinstruments.com November 2005  7 here? BPL is coming . . . . . . and not everyone is overjoyed about it! Last introduced Netcomm’s Lastmonth monthwe we introduced HomePlug, device which uses the Netcomm’sa HomePlug, a device power the home or office whichlines useswithin the power wiring to network within thecomputers. home or office to Broadband over Power Lines (BPL) network computers. takes that idea andPower multiplies by Broadband over Linesit (BPL) many of magnitude. takesorders that idea and multiplies it by many orders of magnitude. T outed as one possible answer to regional Australia’s lack of broadband in the bush, BPL has already undergone a number of trials in Australia and New Zealand, with a large-scale “trial” now under way in Hobart, Tasmania. Aurora Energy (the principal electricty supplier for Tasmania) had already conducted a small-scale trial of BPL in Hobart. This trial, which lasted just two months, was limited to just four houses and two floors of the Aurora Energy building in Hobart. The system used in the trial was based on the DS2 chipset which utilises Orthogonal Frequency Division Multiplexing (OFDM) – with multiple discrete carriers approximately every 1.1 kHz between about 1.6MHz and 30MHz. Apparently Aurora considered the trial a success – so much so that they have now launched a much larger trial over a wider area. And if the somewhat contradictory wording of the Aurora press release (see right) is to be believed, this new trial is the fore runner to a statewide rollout in the not-too-distant future. But what is BPL? In a nutshell, BPL turns the electricity grid into a giant computer net8  Silicon Chip Copyright (C) 2004 Christopher D. Russell – Used With Permission – http://chrisrussell.net work with very fast (they claim up to 200Mbps) internet access. It can work on power lines at local (240/415V) level right up to the many thousands of volts used for area power distribution from zone substations (22kV and 11kV are common in Australia). With the promise of delivering fast broadband to customers without significant new (and costly) infrastructure, BPL has been a pipedream for years – particularly among those who already have a big wired network in place (like power authorities!). It works by impressing a high frequency, digitally-encoded signal onto existing power lines. While this is not a new idea, until relatively recently one major stumbling block was the presence of transformers in the system. These not only reduce the high voltage distributed around the country to more usable levels, but also act as very effective blocking inductors for frequencies significantly above the frequency of our power system, 50Hz (or 60Hz in some overseas countries) . As ever, technology marches on – and technology found a way around the problems, including highfrequency bypasses to get around the transformers. And because the frequency used by BPL is very much higher than the 50Hz mains, it is “relatively” simple to extract the new signal from the mains and use it in much the same way as more traditional broadband delivery methods. That high frequency highlights just one of the significant problems many people are finding with BPL. Depend- This PC was part of the first Tasmanian trial, set up for Aurora Energy staff to try out – with an invitation to do so on top! The white box (alongside monitor) is the interface between the PC and the power line. (Photo WIA). siliconchip.com.au by Ross Tester ing on the system used and the provider, BPL uses a slab of frequencies between about 1.6MHz and 80MHz. This, as readers would no doubt realise, encompasses a fair bit of the MF band (that’s just above the AM broadcast band), the entire HF band (3-30MHz) and a reasonable bite out of the lower VHF band. Poor HF conductors but great radiators That in itself might not be so bad if the HF signal could be contained. But street power wiring is just bare wire, with no electrical shielding at all. Those wires stretched in the air from pole to pole make magnificent antennas, radiating interference right across the spectrum. Even the power wiring within your own home will radiate interference – it too is not shielded, only insulated. It’s not hard to understand that power distribution lines make very poor HF carriers anyway. They were designed for 50Hz AC. At a pinch, they could be expected to perform reasonably up to, maybe, a couple of hundred kilohertz – not the tens of megahertz used for BPL. That’s just another reason that BPL has had some rather significant technical hurdles to overcome. According to the BPL people, they have done just that. According to opponents, they have done nothing like that. In a BPL trial currently under way in Cottonwood, Arizona (USA), amateurs report that HF bands are not usable within 70m of the power lines and the interference can still be heard nearly a kilometre away. BPL interference sounds like particularly bad “static” in the receiver, all but wiping out the ability to listen to even strong, local signals. As for the weak, overseas contacts which amateurs strive for . . . forget it! Australian amateur operators, with frequency allocations at 1.8MHz, 3.5MHz, 7MHz, 10MHz, 14MHz, 18MHz, 21MHz, 24MHz, 28MHz and 52MHz, are hopping mad. Via their peak body, the WIA, they have launched a major drive to force authorities to stop BPL before it gets a foothold. They cite S197 of the Radio Comsiliconchip.com.au PRESS RELEASE Datafast in World First Broadband Over Power Line Deployment 13 September 2005 Partners Mitsubishi Electric and Aurora Ene rgy in Commercial Roll-Out of New 200Mbps Communications Technology Datafast Telecommunications Limited (ASX :DFT) today announced the launch of the world’s first large-scale comm ercial trial of 200 Megabit Broadband over Power Line (BPL) technology , in conjunction with Aurora Energy and Mitsubishi Electric. BPL delivers ultraband Internet access at up to 200Mbps – speeds vastly quicker than any DSL technology, dwarfing effor ts to coax 24Mbps from existing telephone lines with ADSL 2 and 2+. The commercial trial is the first step in linkin g Aurora Energy’s extensive electricity network throughout Tasmania – near ly 25,000 kilometres reaching 250,000 homes and businesses – with leadi ng edge technology from Japan’s Mitsubishi Electric. Datafast CEO Simon Ehrenfeld said, “Mitsubish i has delivered something genuinely exciting, not just for geeks but also for the business people in our industry. We anticipate excellent results from the commercial trial, and we believe that the partners in this project have a three year head start on other Internet providers. This is not a techn ical trial – the technology works. This is the first stage of a commercia l roll-out.” “We are providing significant expertise in the areas of data management and billing systems. Datafast’s intellectual prop erty has been developed in-house over a long period, and enables the simple and effective management of complex Internet session data.” Mitsubishi has only recently released its comm ercial 200 Megabit BPL product and Aurora is one of the first comp anies in the world to deploy this new technology commercially. The commercial trial launched today will run for approximately nine months – initially with customers in Hobart and then extending to other parts of the State. This trial will offer broadband data as well as “Voice-over-IP” services via existing power points in homes and busin esses. A smaller number of customers will also be involved in trials of video via the power point during this period. BPL is attracting interest around the world with some of the global electronics and communications companies – such as Mitsubishi, Sony and Panasonic – joining forces to ensure integratio n into every home appliance, from fridges to air-conditioning units. November 2005  9 Power Generation and high voltage transformers HV (110-330kV and more) Distribution HV Substation and BPL input MV (10-25kV) Distribution Transformer HF Bypass and Coupler Low Voltage (240V) Street Distribution A somewhat stylised and simplified diagram showing the power distribution system and how Broadband over Power Lines is made available at street (and therefore home) level. There is no doubt that BPL works well and offers many advantages such as speed and existing infrastructure. There is also no doubt that those long power lines act as magnificent radiators, blotting out much of the MF, HF and VHF bands. munications Act, 1992, which protects radio communications services from “substantial interference”. Whether by fiendishly clever design or simply dumb good luck (we’ll leave you to make up your mind which) BPL has avoided heavy-use areas of the spectrum where there could be huge public outcry. BPL frequencies are above the AM broadcast band (though BPL harmonics could be a problem in low-level AM signal areas). They’re below the FM broadcast band (perhaps ditto, perhaps less likely). They have even avoided most VHF TV channels. And of course they’re way below mobile phones. They are, however, right over the top of HF CB radio. Then again, that might not be such a bad thing (have you listened to 27MHz CB lately??). Interference back at ya! Amateurs aren’t just concerned about the ability of BPL to dramatically curtail amateur radio activities. It goes back the other way. They have convincingly proved that a fully legal, licenced and operationally correct HF radio transmitter has the ability to stop BPL dead in its tracks. And they have the documented evidence to back up the claim. Even operating a relatively low 10  Silicon Chip Coupler and Backhaul Broadband Service Provider Each home has powerline modem power transmitter in the vicinity of a BPL user is highly likely to interfere with BPL so severely that the user’s computer either rejects it all as garbage or maybe even crashes, leaving the broadband user believing that they were “wronged” by that *&$%<at># ham radio geek next door. Following decades of complaints about interference to neighbour’s radio and television services (RFI and TVI), amateurs are now faced with unwarranted and underserved flak from BPL users, who don’t understand the notion that the licensed amateur radio operators are doing nothing wrong and, indeed, “were there first!” In many, perhaps most, cases the amateur can show that the neighbour’s equipment is at fault, not their’s. But does that matter? If previous TVI experience is any yardstick, amateurs expect that authorities will demand they cease operation, then – perhaps – try to find cures for the problem, rather than upset powerful media organisations. Years of experience suggests that when it comes to TVI and RFI, even when amateur operators are right, they’re wrong! Amateur operators in many other countries have launched similar campaigns to those in Autralia. The US American Radio Relay League has a neat BPL analogy: using the traffic Here’s part of a BPL installation in Briarcliffe Manor, NY state, USA, which was responsible for a large amount of interference in the area. The ball-shaped object under the high voltage cables at the top of the pole is responsible for extracting the BPL signal; the grey box then impresses this signal onto the low-voltage cables feeding homes and businesses. (Photo N2YGK). siliconchip.com.au lanes of a busy, multi-lane freeway as a garbage dump. It’s not just amateurs . . . While it seems that amateurs have made the most noise, they aren’t the only ones who are worried about BPL. Their concerns are echoed by emergency services, the military, HF business radio users and many others who have already experienced the disruption BPL can cause. Even the Salvation Army has lodged objections in the US! In some areas, BPL has already been banned (or at least put on hold), primarily due to its proven interference potential. Shortwave radio listeners will be seriously affected. Many of the stations listened to are already “down in the mud” – imagine how much worse that will be with continuous, loud, crackling, interference. And with many third-world countries looking at BPL as a low-cost way to join the broadband club, services to those areas from organisations such as Radio Australia might be in jeopardy. It’s getting quite nasty On the other side of the equation, BPL advocates represent a powerful lobby group and are using that power to convince regulatory authorities that they are not the threat their opponents claim them to be. They maintain that they can “notch out” interference near the homes or premises of affected users. Opponents counter this by claiming that if they notched out all affected frequencies, particularly in a major city, then there would be no spectrum left for BPL to work in! Moreover, this doesn’t take into account mobile radio users – you can’t notch them out! And there are countless reports of “notched out” fixed operators still being basically forced off the air by BPL interference. Opponents are also very quick to dispute the wonderful claims made by BPL suppliers, and there are plenty, as propaganda from vested interest groups with big $$$ to back them up. Most of the positive – in some cases downright glowing – BPL reports in the media are dismissed as simply paid-for PR, with the negatives never mentioned. Indeed, amateurs are crying “dirty pool” when it comes to many media siliconchip.com.au reports, even here in Australia. They claim that BPL interests are playing the man, not the ball, trying to discredit both the amateur organisations and the people they represent. It has become quite nasty at times. Amateurs are also keen to point out that they are not anti-broadband, per se. They maintain that, as technically qualified people, they are often at the forefront of development of new technologies and equipment; they are in fact often the “early adopters” of such. Power Line Control Some readers might be wondering about the difference between Power Line Control (PLC) systems, which also impress signals on the power lines, and BPL – and why there haven’t been significant complaints about PLC (which has, after all, been around for decades). The most common PLC signals are those which are used to switch “off peak” water heaters, etc, on and off. There are two major differences between PLC and BPL. First, PLC signals are usually below 500kHz (often 150-180kHz), so are nowhere near as threatening as HF/VHF signals. Second, and probably more important, is the very intermittent nature of PLC signals – just a few seconds every few hours. BPL is the opposite – it can be virtually continuous, depending on the user and usage. The last mile The last mile is an expression used by service providers to denote the link to actual users, the paying customers. It has nothing to do with any measurement (indeed, most last miles are a lot less than a mile!). Here BPL gets at least a little interesting. In some trials in the US, BPL has been much as described here, with adaptors plugged in to the power line. However, in others, they’ve used WiFi links, either very local ones from the poles to houses and offices or, in some cases, they’ve created higher power WiFi WANs (wide area networks), capable of servicing perhaps a block of houses or office buildings. There is plenty of “last mile” development going on at the moment; it is quite likely that there will be even more innovative approaches. Just as long as they solve the interference problem first! SC An addendum: EOP Interference A number of readers have questioned the amount of interference to HF/VHF radio from the NetComm NP210 “HomePlug” Ethernet Over Power (EOP) devices which we reviewed last month. To be honest, we tried to look at radio interference at the time of the review but as Murphy would have it, at that exact moment (quite literally the day before our October deadline) my old Yaesu HF transceiver decided to give up the ghost and I couldn’t quickly lay my hands on another communications (HF) receiver. I can’t blame the Yaesu – it’s been a long time since I last used it [in fact years, since I ceased renewing my amateur station licence – I couldn’t justify contributing to Government coffers for the amount of use it got] and it did/does live in a fairly salt-air coastal environment. Anyway, since then I have managed to repair it and rigged it up once again. After a dial-twiddle through the entire band (0.5-30MHz) to get some feel for the amount of current “background” interference, I fired up the HomePlugs and repeated the exercise. The difference was, to say the least, alarming. In many places through the HF spectrum, where the background QRN/ QRM had been hardly bothering the Smeter, it was now S5-S7, peaking S8, and rendering those bands virtually unusable. I guess the closest analogy I can make is continuous thunderstorm crashes on a distant AM station, with an underlying modulation. (In fact, you could watch the NP210 activity LED flash in sympathy!) The bands 4.5-6.9MHz, 8.0-9.9MHz, 10.5-13.9MHz, 14.5-15.1MHz and 16.520.8MHz were all badly affected. Now I’m not a conspiracy theorist – but notice that the 3.5, 7, 10, 14 and 21MHz amateur bands are all missing from this list? Could the manufacturers deliberately have notched out those bands to minimise complaints from amateur bodies? Nevertheless, if the interference from a single, low power EOP device is this bad, I hate to think what a broad-scale BPL implementation is going to do to all radio users, not just amateurs. So far, I haven’t had the fortune (?!!) to experience real, live BPL interference – I have listened to it extensively via examples on the ’net (Google BPL interference . . .). If that’s what the future of broadband promises, perhaps it’s time to apply the brakes and re-think. November 2005  11 CAR SOUND ON THE CHEAP Pt.1: By JULIAN EDGAR You can put together a good in-car sound system for just $200-300. Here’s how to go about it. I F YOU’RE LUCKY enough to sit in a late model Audi or Lexus or BMW, take the opportunity to crank up the sound system and have a good listen. Especially in the Lexus, you’ll be blown away by the brilliant sound system – a system with crystal clear highs, realistic mid-range and bass which is strong but never overemphasised. If you’ve got time, look at the compo- nents that make up the sound system. To your surprise, you’ll probably find a fairly normal looking “head” unit, a few amplifiers tucked away under seats or in the boot, and a subwoofer in the rear deck that looks paltry compared to what you probably expected. By now, you will probably be wondering how come this system sounds so good compared with those owned by the “doof-doof” guys, who always seem to think that multiple 30cm woofers and about a kilowatt of amplifier power are needed to get even semi-decent sound. There will be other questions as well – such as, where are the huge cables, the gold-plated connectors and the sheer physical intrusiveness of the sound system that you thought were necessary for good in-car sound? Of course, the answer is that if you This ex-Mercedes Benz AM/FM CD head unit (made by Eurovox) cost only $100 secondhand. It lacks line-level (RCA) outputs but boasts a clear and logical layout, “key-off” play (ie, it can be kept playing for a while after the ignition key is removed) and bass and treble controls. It’s typical of the sort of quality secondhand car gear that’s now available. 12  Silicon Chip siliconchip.com.au don’t want to make your ear drums bleed. Most of that stuff simply isn’t needed! There’s no getting away from the fact that premium car sound systems are good – it’s just that most of us don’t have the $180,000-odd needed to buy the car that fits around that type of system. In fact, chances are, the sound system budget that you’ve got to work with will be limited to just two or three hundred dollars. But even with that sort of budget, you can do a lot better than you’d first think. So, in this article, we’ll look at the techniques and tactics you can use to acquire and install a sound system in your car that’s more than just competent. It won’t be an ear-bleeder but if you like accurate imaging, very good frequency response and excellent clarity, it’ll be just fine. In fact, it’ll be about as good as the systems featured in cars costing around $75,000. Head unit The current buzz in car sound can be spelled out by three characters: MP3. Most new CD players on the market will read MP3-encoded CDs and even many CD stackers will work with this compressed music format. Other MP3 car systems use computer hard-drive based designs and there are some head units that accept MP3-encoded memory cards. As for us – well, we can forget about all of them. Why? Well, with the current fashion being MP3, “old format” CD players are being discarded in large numbers. This has driven down their price in the used market to the extent that you can now buy a used good-quality single CD AM/FM head unit for under $100. Yep, less than one hundred dollars. For that, you get original equipment quality with a competent power rating per channel (eg, 4 x 35W), bass and treble controls and even RCA linelevel outputs (so you can connect an amplifier if you want). Of course, you could also buy the very same thing new for about $300. In case you’re wondering, this isn’t one of those stories where the author doesn’t have first-hand experience. In the last six months, I have bought and installed three good quality secondhand single CD AM/FM car radios: an ex-Mercedes Benz unit (manufactured siliconchip.com.au These ex-Mitsubishi 5-inch wide-range speakers have excellent efficiency. High efficiency is vital if you are to generate adequate sound pressure levels (SPLs) without spending a lot of money on amplifier power. by Eurovox) which cost $100 secondhand, a near new Hyundai CD radio ($75) and a Philips unit ($100). None was older than two years. But let’s be clear about the disadvantages: these head units won’t read MP3-encoded CDs, they’re single CD rather than multi-CD capable (and they usually can’t control a CD changer), and they’re all fairly conservative in appearance. The first two downsides are the sort where you shrug and look at the low cost, while the latter is actually a potential benefit – most car dashboards are visually staid and in a few years time, this type of head unit won’t look garishly silly, as will some current head units on the cutting edge of fashion. Where to go, what to look for So where do you get a new front-end at this sort of cost? On-line auction site eBay is a good source, as are secondhand stores like the Cash Converters chain. The classified ads in major newspapers and in newspapers such as the “Trading Post” (which also has an excellent website) are also worth a good browse. And what do you look for? As with many secondhand goods, the desirability of an item depends on its brand name, features and history. Let’s look at each of these in turn: BRAND NAME: today, many electronics goods are made very cheaply, branded with a newly-minted name and then sold off to make a quick dollar. You don’t want one of these head units! Instead, look for known, wellestablished brands – though remember that some old brands have been bought by new vendors who have no interest in good design and production. It’s therefore best to go for names that are associated with current premium consumer electronics – rather than older brands from hifi circles. FEATURES: in the price bracket we’re talking about, you should be able to get a full digital unit with bass and treble controls, random and repeat CD functions, and line level (RCA) outputs. It should also have an inbuilt 4-channel amplifier with reasonable power outputs. HISTORY: why is the vender selling the unit? The best answer is that they have just bought the car and they’ve decided to immediately upgrade the head unit. When buying a secondhand head unit, it’s critical to be absolutely certain that you have access to the security code. Nearly all modern original November 2005  13 Here’s another $100 bargain. This Philips RC604 AM/FM CD is a fully-featured, original equipment unit that was bought on-line through the eBay auction site. When buying a head unit, make absolutely certain that the vender has the correct security code available for it. Without the code, it’s just junk. equipment head units are security coded – if the vender doesn’t have the code, you won’t be able to make the device work. That’s a very important aspect to keep in mind – it’s easy to be blinded by an apparent bargain without realising that without the code, it’s actually no bargain at all! Of course, you don’t need to buy ex-original equipment players – there’s also a multitude of secondhand aftermarket head units to pick from. However, because they’re more likely to have flashing lights and be every colour but black, these command higher prices. Full-range speakers As anyone who has played with hifi speakers will ruefully attest, speakers are something of a black art. That’s even more the case in a car where the enclosures(?) often comprise sonically awful spaces like the insides of doors and kick-panels. 14  Silicon Chip When looking for secondhand speakers, there are a few basic factors to keep in mind, as follows . . . EFFICIENCY: often completely overlooked, the efficiency of the speakers is vital in car applications. Why? – well, when amplifier power costs lots of money, you can save literally hundreds of dollars by picking up speakers which have high efficiency. In this context, the word “efficiency” has a very specific meaning: we want as much sound output as possible from the speaker for a given input of electrical power. Efficiency is measured as the Sound Pressure Level (SPL) that’s developed on axis with an input power of one watt (1W). The higher the number the better, because if you drop by 3dB, you’ll need to double the amplifier power to get the same SPL! POWER HANDLING: this is measured in watts and in cheap speakers is a largely meaningless specification! The naïve might think that a speaker rated at 50W can handle an input power of 50W without distortion. But nothing could be further from the truth. It’s very likely that with a 50W input, the speaker will sound awful! In fact, long experience has taught me that with full-range speakers, I can basically ignore what ever power figure is written on the back. Instead of worrying about watts, just make sure that you get efficient speakers and then never drive them into audible distortion. SIZE: this is important for two reasons. The first is that larger speakers are typically more efficient and secondly, the speakers will need to fit in the designated spots – unless you do lots of metal cutting, of course. Three-inch (7.5cm), four-inch (10cm), five-inch (12.5cm), six-inch (15cm) and 4 x 6-inch oval speakers are the most common full-range sizes used in cars. This means that you should have a good look at the factory spaces provided in the car for speakers, including (critically!) the available mounting depth. If the speakers are to go in the doors, don’t forget to lower the glass before you make your measurements! DESIGN: as with all speakers that need to develop a bass response, look for a long-throw suspension (eg, a deep rubber surround) and a large magnet. As a very broad rule of thumb, better designed speakers are heavier – their frames are made from thicker materials and the magnets are larger. That’s not to say that a heavy speaker is inevitably a good one but more often than not, a light speaker is a bad one. If you don’t intend to use separate tweeters, dual-cone drivers will have a slightly better top-end response than single-cone speakers. Watch what you buy Buying cheap speakers new usually ends in tears. These speakers often have miserable power handling capacity and worse still, terrible efficiency. So to get decent SPLs (sound pressure levels) out of them, you drive them into distortion and that’s a really good way of damaging them. Great! Instead, it is better to do one of two things: (1) either source secondhand speakers from other cars; or (2) source secondhand speakers from other appliances. On the car scene, really good bargains can often be picked up – say $10 for a pair of dual-cone 6-inch exsiliconchip.com.au Matched midrange/woofers and tweeter combinations can easily be gained cheaply from non-automotive sources. Discarded large-screen stereo TVs often have a pair like this inside – just make sure that they are 4-ohm units. original equipment car speakers. Yes, that’s right – $10. However, if you don’t mind getting your hands dirty, there’s an even cheaper source. Big sound TVs of the last 15 years run speaker systems that are ideal for car applications. And like CD players, TVs are being discarded in a fashion frenzy – this time, due to consumer demand for direct S-video and component video inputs and for widescreen picture formats. At roadside kerb collections and municipal tips, you can get a stereo TV for nothing – well, for one or two dollars, anyway. The speakers inside normally comprise four or five-inch, roll-cone woofers (or combined midrange/woofers) and matched tweeters, complete with crossover capacitors. Sure, the power rating written on the woofers might be only 5W or something similar but ignore this. A genuine manufacturer’s 5W can easily be equivalent to the fantasy 50W markings on many cheap car sound speakers. Follow these basic steps In any case, when buying speakers, you should follow these basic steps: (1) Cull the selection down to the sizes that suit your application; (2) Manually move the cones of the larger speakers up and down (ie, by spreading your fingers and applying pressure across the face of the cone), to siliconchip.com.au This dome tweeter gives excellent treble and has a crossover capacitor already attached. It costs only $5 from Jaycar Electronics and was part of a job-lot of original equipment tweeters bought by the company. November 2005  15 How To Identify The Wires make sure that nothing is binding; (3) Inspect each unit for water damage, perished rubber suspensions and cone damage, etc; (4) Check to see if they carry a wellknown good-quality brand. Once you’ve done all that, you can select individual speakers on the basis of magnet weight, power rating and cone throw, etc. Buy 4-ohm speakers If you buy a secondhand head unit that comes without wiring instructions, you could be in for a rude shock – there might be 15 or more unlabelled wires emerging from its rear panel! Connect them up wrongly and the head unit might never work again! The first step to solving this is to check the unit itself. Often, there will be a wiring diagram attached to the top of the unit. If not, do a web search for the brand and model number. If that doesn’t bring up a clearly labelled wiring diagram, go back to the unit and take a close look at the wiring harness. Assuming a 4-channel unit, the first step is to identify the leads that go to the four speakers – ie, eight wires in all. These eight speaker wires are likely to be grouped into pairs – eg, two yellow, two green, two orange and two white. One of each pair is always marked with a trace, which indicates the positive lead. Next, you need to identify the power (+12V) and earth wires – and it is critical that you get this right! The earth wire is usually black, green or brown. The +12V power lead is usually red and often has an inline fuse or external noise suppression filter. There will also be an ignition-switched lead (often yellow) and a lightson input (often orange). In addition, there may be a telephone mute input (sometimes pink) and an electric aerial wire (also often yellow). However, before exploring the other lead functions, make sure the device powers up correctly – but only after you’re reasonably sure that you’ve identified the power leads. If you have a variable-voltage power supply with current limiting, start off with both its voltage and current settings wound right down. You can then gradually bring both up, while keeping an eye out for any problems – most head units at idle draw only about 0.75A. Once the supply connections have been sorted, you can carefully work out the functions of the others. Don’t forget that you’ll need the security code handy when the unit powers up on the bench. With this done, connect a single speaker to each pair of “like” colour speaker wires and then twiddle the fader and balance controls. This will soon allow you to sort out which speaker wire pair is which. Be sure to label the wires as soon as you know their function! 16  Silicon Chip It’s important that you select speakers that have an impedance of four ohms (4W) rather than 8W. That’s because car sound systems are generally designed to drive 4-ohm speakers and so they will not deliver as much power to an 8-ohm speaker. In practice, this may not be important because the 8-ohm speaker may well be more efficient that the 4-ohm speaker. And if you have the space, you can always install two 8-ohm speakers in parallel to get more power. If you have a number of speakers to choose from, make sure that you do some comparative bench testing. Tested bare on the bench, the speakers will sound terrible in that they will lack any bass response – but there shouldn’t be any “pops” or “buzzes”. Furthermore, you should be able to get a feel for the relative power handling and efficiency. Using your domestic hifi amplifier for this testing is usually fine, despite the lower speaker impedance. However, always turn down the wick if you hear distortion – a rule that applies in any sound system. How much so far? Depending on how resourceful you are, a pair of wide-range speakers – or, better still, two sets of matched woofers/midranges and tweeters – should cost you no more than about $25. Most cars have four full-range speakers (ie, front left, front right, rear left and rear right) but consider the option of using only the front speakers. If there’s frequently only one or two occupants in the car, those people will get improved imaging and you’ll also save some money. So depending on which way you go (and we’ll take the more expensive 4-speaker set option), so far you’ve spent about $150. Next month we’ll look at amplifiers and subwoofers and describe how to set up the system. SC siliconchip.com.au AJF MIC0002 Coming soon. Soon after that? Then maybe? Or what about? Or even? Exclusive to Then who knows? Introducing... by Ross Tester It’s not just a brilliant new concept . . . it’s a revolution! D o you remember the thrill of putting together your first Meccano project or Lego construction? Microbric is ready to bring that thrill to a whole new, more technical-savvy generation – a generation which has grown up with personal computers; a generation which is looking for more challenges than simply putting something together. They’re wanting things that work! mother-board containing a programmable microcontroller. The microcontroller is supplied already programmed to use a simple language called BASIC, which can be learned in a relatively short amount of time. And then constructors can program and reprogram the microcontroller as often as they wish to make their Microbric project do, well, whatever they want it to do! It’s now much more than “the thrill of the build” – though that is still important. They want something that will impress family and friends. They want something that won’t sit on the shelf when it is finished, because it does something... and then can be used over and over. Connected to the motherboard are peripheral modules. These modules are what generally interface the motherboard with the outside world. To be progressively released next year, they come in a variety of different shapes and sizes and perform a range of functions. Some typical modules are: Power supply Module - DC Motor Controller Module - Relay Module - Button Module - Temperature Sensor Module - Wireless Communication Modules - And so much more. Microbric is the brainchilld of a young Adelaide designer, Brenton O’Brien. And in conjunction with the leading Adelaide Metropolitan newspaper, the Advertiser, Microbric will be released later this month, with the low-cost Microbric packs available through newsagents every day, building to a full Microbric project . What they are looking for is Microbric, an Australianmade, brand new concept. But what is Microbric? Microbric is a patented system of interconnecting electronic modules, enabling constructors to build, with just a screwdriver, an impressive range of devices. Like Lego and Meccano construction kits they are challenged into building things. The difference is that every Microbric project is alive! At the core of the system is the reusable Microbric Edge and connector “bric” which has three conductors supplying 5V, ground and data. The plastic bric is used to connect two Microbric Edges together (either side-by-side or stacked) then use clamping screws and spacers to not only hold them together, but complete the electrical and data circuits. Every Microbric construction has a pre-assembled 18  Silicon Chip Microbric projects will become available Australia-wide through Dick Smith Electronics. siliconchip.com.au The Microbric concept explained: each Microbric unit clips to another Microbric unit (or to a Microbric motherboard) with a plastic “bric” and screws/nuts to hold it together and also complete the Single Microbric circuit. Units clip together Microbric motherboards are made to a standardised modular design, so a whole number of Microbric units will mate with it perfectly. The concept is so simple, yet so inherently brilliant! Microbric units will be available to sense, measure, control, move, communicate ... Screws hold together AND complete circuit Single Microbric Units – these could be sensors, motors, LEDs, piezos, etc, etc. Plastic “bric” Plastic “bric” Nuts Because of the modular nature of Microbric, its inherent you want your Microbric project to do something different! safety and the fact that it can be re-used almost indefinitely, Each Microbric unit measures 20.3mm x 20.3mm (800 it has already attracted a lot of attention from education mils in the old money!) and is made from double-sided, authorities as a “hands on” teaching gold-flashed 2mm fibreglass tool. Even R&D departments have Nothing more than a screwdriver needed to build! PC board. Both sides have No soldering, no toxic fumes, safe low voltage! expressed interest in Microbric due red and black screening to Or program and reprogram using BASIC! to its modular nature – just screw the clearly identify the + and – Rebuild over and over into different configurations! bits together and they connect! connections. Hobbyists and enthusiasts will benefit Next month, SILICON CHIP from the fact that Microbric is reusable will feature one of the Microbric projects to build yourself – over and over again – you don’t have to buy anything new unless in fact, the “Viper” robot shown on the opposite page. SC Here’s the I-BOT, the first Microbric project which will be launched in the Adelaide Advertiser/Sunday Mail commencing November 21st. Each day, a separate pack (see examples below) will be available from Newsagents. By the end of two weeks with feature articles every day in the paper, this robot will be the result! The IBOT is fully programmable (a “barcode” will be published in the paper to allow it to self-program from its inbuilt sensor). The same sensor makes it a line-follower robot and a special “track” will also be published in the paper. Each section of the robot will be explained as the packs become available. SILICON CHIP is assisting in the preparation of editorial material for the newspaper articles. Microbric IBOT daily packs (below) build to the full IBOT at right! siliconchip.com.au November 2005  19 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au This prototype unit differs slightly from the final version, which now also features a second headphone socket, so that two people can listen at the same time. By PETER SMITH Studio Series Stereo Headphone Amplifier A Top - Cl as s Un i t F or T he A u dio E n t h usias t ! Here’s a top-class headphone amplifier that can drive high or low-impedance ’phones to full power levels, with very low noise and distortion. For best performance, it can be teamed with the Stereo Preamplifier described last month. Alternatively, it can be used as a standalone unit, requiring only a power supply and a volume control pot for use with any line-level signal source (CD/MP3 player, etc). It even includes dual outputs, so you can listen with a friend! 26  Silicon Chip siliconchip.com.au M ANY OF OUR HIGH-POWER audio amplifier designs already provide an output for headphones. The additional circuitry required for headphone support is simple; just two resistors in series with the loudspeaker outputs to limit the drive current and protect the ’phones in the case of amplifier failure. Considering its simplicity, this resistive limiting scheme works well, although it will cause distortion if the load is non-linear – a likely prospect with most headphones. Apart from eliminating this potential source of distortion, there are a number of other reasons why you might consider building a separate headphone amplifier. For a start, not everyone owns a pair of top-rated headphones or even a high-performance power amplifier. After all, an amplifier that equals or betters the performance of this new headphone amplifier will set you back more than a few shekels! Another reason might be for use with the latest “high-tech” audio electronics gear. The headphone outputs in much of this gear cannot drive low-impedance ’phones – or at least not to decent listening levels. In addition, available output power in portable devices is deliberately limited to conserve battery energy. This means that lots of distortion might be present at higher listening levels, even with sensitive headphones. One way around this is to feed the line-level outputs of this gear into your power amplifier and then plug your low-impedance headphones into that. That works but then you’re tethered to an immovable object. Besides, the power required to drive headphones is around 1/1000th of that required to drive loudspeakers, so a large power amplifier could be considered a tad oversized for the job! Features & Performance Main Features • High performance – very low noise & distortion • Drives high and low-impedance headphones • High output power (up to 200mW into 8W and 32W) • Dual headphone sockets – can drive two pairs! • Works with a preamp or any line-level audio source Measured Performance Frequency response.............................flat from 10Hz to 20kHz (see graphs) Rated output power....................200mW into 8W and 32W, 85mW into 600W Max. output power (current or voltage limited)..................... 575mW into 8W, 700mW into 32W, 130mW into 600W Harmonic distortion......................................... typically .0005% (600W load), .001% (32W load) and .005% (8W load) Signal-to-noise ratio (A-weighted).................. -130dB (600W), -120dB (32W) and -111dB (8W) with respect to 100mW output power. Channel crosstalk ..................................better than -68dB from 20Hz-20kHz at 100mW output power (see graphs) Input impedance.......................................................................~47kW || 47pF Output impedance................................................................................... ~5W Note: all tests were performed with the amplifier driven from low source impedance. For crosstalk measurements, the non-driven input was backterminated into 600W. Design outline One of the challenges in designing a general-purpose, low-distortion headphone amplifier is catering for the huge variation in headphone specifications. Models with 8W (nominal) impedance are common, as are 32W, 60W, 120W and 600W versions – and many in between. At the high impedance end of the scale, a large output voltage swing will be necessary to develop full power, whereas at the low end, current limiting is needed to prevent driver siliconchip.com.au Fig.1: these plots of distortion versus frequency at 100mW highlight the impedance non-linearity of a real pair of 8W headphones. When driven directly from the low-impedance headphone amplifier output, performance is very good (bottom curve), as the amplifier’s feedback loop can act to linearise the signal. However, when isolated with a 47W series resistor (top curve), the headphone’s non-linearities are immediately exposed! November 2005  27 Par t s Lis t – Headphone Amplifier 1 PC board, code 01111051, 134 x 103mm 2 PC mount switched RCA sockets (CON1, CON2) 2 6.35mm PC mount switched stereo sockets (CON3, CON4) 1 3-way 5mm/5.08mm terminal block (CON5) 1 8-pin gold-plated IC socket 4 TO-126/TO-220 micro-U heatsinks 4 M205 PC mount fuse clips 2 M205 500mA fast-blow fuses 4 M3 x 10mm tapped spacers 4 M3 x 6mm pan head screws 4 M3 x 10mm pan head screws 4 M3 nuts and flat washers 2 11.8mm I.D. plastic bobbins (Altronics L-5305, Jaycar LF1062) 1 2-metre length of 0.63mm enamelled copper wire 1 120mm length of 0.7mm tinned copper wire (for links) Semiconductors 1 OPA2134PA dual FET-input op amp (IC1) (Farnell 791-039) 2 BC557 PNP transistors (Q1, Q5) 2 BC547 NPN transistors (Q3, Q7) 2 BD139 NPN transistors (Q2, Q6) 2 BD140 PNP transistors (Q4, Q8) 4 3mm red LEDs (LED1-LED4) (Altronics Z-0700) or headphone burnout at abnormally high volume settings. Another consideration is headphone impedance variation with frequency. While distortion due to this effect can be minimised with low amplifier output impedance, this requirement would seem less important than when driving loudspeakers. We’re also aware that some manufacturers are producing models that have virtually flat impedance curves over the audio spectrum and so will be unaffected by an amplifier’s output impedance. In fact, international standard IEC 61938 specifies that headphones should be driven by a 120W source, regardless of headphone impedance. Alas, it seems unlikely that all headphones will exhibit the ideal “flat” (purely resistive) impedance response. To test this theory, we drove a pair of reasonable quality 8W headphones first 28  Silicon Chip 12 1N4148 diodes (D1-D12) Capacitors 2 470mF 25V PC electrolytic 4 100mF 16V PC electrolytic 2 10mF 35V/50V non-polarised PC electrolytic (max. 6.3mm diameter) 6 100nF 50V MKT polyester 2 47nF 100V polyester film (greencap) 2 1.2nF 50V MKT polyester 2 100pF 50V ceramic disc 2 47pF ceramic disc Resistors (0.25W, 1%) 2 47kW 4 1kW 2 7.5kW 8 100W 8 4.7kW 2 47W 1W 5% 2 1.2kW 2 10W 1W 5% 2 2kW 4 4.7W 0.5W 1% Additional items 2 RCA plugs Shielded audio cable 1 50kW dual-gang log pot (for standalone use) 2 panel-mount RCA sockets (for standalone use) For power supply upgrade 2 TO-220 micro-U heatsinks 2 M3 x 6mm pan head screws 2 M3 nuts and flat washers from a low-impedance (5W) source and then added a 47W series resistor. The results are presented in Fig.1. The maximum amplifier output power needed to produce the desired volume level depends on another widely varying parameter: headphone sensitivity. Modern dynamic headphones are very efficient, typically producing 90-100dB SPL (sound pressure level) per milliwatt of input, with many reaching full volume with just a few milliwatts. To cater for varying sensitivity levels, commercial headphone amplifiers are typically rated at between 10mW and 100mW, or more. Unfortunately, the impedance rating of a headphone pair is not necessarily related to its sensitivity, so a general-purpose amplifier design will ultimately be a compromise. It must generate sufficient volume when driving low-sensitivity, low-impedance phones but may well overdrive highsensitivity and/or high-impedance models at high volume settings. It must also remain stable when driving varying impedances and be able to develop full power into 8W units. Updated & uprated A number of headphone amplifier designs have been published in SILICON CHIP over the years. Some are part of larger amplifier or mixer projects, whereas the most recent (described in May 2002) is a standalone module. All are similar in design, using complementary emitter-follower outputs to boost the current-handling capability of an op amp. Although the heart of this design still relies on the old boosted op amp idea, it includes a number of improvements to significantly boost power handling and performance as well. In addition, we’ve carefully designed the PC board layout to minimise distortion and crosstalk. The result is a unit that clearly outperforms our previous designs in all areas, yet is still relatively inexpensive and easy to build. Let’s look at the circuit in more detail. Circuit description The amplifier consists of two identical circuits, labelled “left” and “right” to represent the stereo audio channels. To reduce clutter, the circuit diagram (Fig.2) shows only the left channel. Note that some components are common to both channels, including the power supply input connector (CON5), fuses (F1 & F2), filter capacitors and headphone output sockets (CON3 & CON4). An RCA socket (CON1) accepts the audio signal, which is AC-coupled to the circuit via a 10mF capacitor and terminated with a 47kW resistor. A 100W resistor and 47pF capacitor form a simple RF filter, after which the signal is fed into the non-inverting input of an op amp (IC1a). In common with the Studio Series Stereo Preamplifier, we’ve used an OPA2134 audio op amp here for best performance. These op amps have excellent load-handling characteristics, with the ability to drive loads down to 600W while producing very low distortion. Of course, this falls far short of our 8W load requirement so a current booster stage has been added between the op amp and the amplifier output. As mentioned earlier, the booster siliconchip.com.au Fig.2: the circuit is based on an OPA2134 high-performance audio op amp (IC1), which drives a complementary emitter-follower output stage. This significantly boosts the amplifier’s output current capability and therefore its maximum power output. Only the left channel is shown here – the right channel is identical. stage is based on a pair of mediumpower transistors (Q2 & Q4) connected in a complementary emitter-follower configuration. Let’s look at the positive (uppermost) half of the circuit first. Current source Transistor Q1, a red LED and a 100W resistor form an active current source. With about 1.8V across LED1, close to 10mA flows in Q1’s collector circuit and this is used to drive the base of output transistor Q2. Of note here is the choice of LED type; it must be red in colour and must not be a high-brightness type – just a standard 3mm type. The device we’ve selected (Altronics Z-0700) exhibits the desired forward voltage (1.8V) at the programmed current. Similar types may also be suitable. A current source greatly improves the amplifier’s supply rail rejection when compared to the simpler resistive biasing that could also have been used. Further improvements can be seen in the base circuit of Q1, where we’ve split the usual single bias resistor into two 4.7kW halves and added a 100mF filter capacitor to the centre point, again improving ripple rejection. Note that the use of a LED instead of the more traditional diodes in this instance is really just for convenience, although it does provide a useful visual indication of operation. In the quiescent (no input signal) state, most of the current flows into the op amp’s output terminal (pin 1) via diode D5. This diode compensates for the base-emitter voltage of Q2, to minimise crossover distortion. In practice, the forward voltages of D5 and Q2 will not be equal. Typically, the transistor will have a slightly lower forward voltage, so several milliamps (typically around 15-20mA) will flow in the emitter circuit of Q2 in the quiescent state. A 4.7W resistor adds a measure of stability to the emitterfollower configuration. The other half of the circuit (Q3, siliconchip.com.au November 2005  29 Fig.3: follow this parts layout diagram closely when assembling the headphone amplifier. Be careful not to mix up the different transistor types and double-check the orientation of the diodes, LEDs and polarised electrolytic capacitors before applying power. LED2, D6 & Q4) is powered from the negative supply rail and operates in a complementary fashion, with the output transistor conducting on negative, Fig.4: here’s how to assemble the heatsinks to the output transistors, which must be done before fitting the transistors to the board. Make sure that the metal face of each transistor mates with the heatsink and be sure to smear both mating surfaces with heatsink compound. 30  Silicon Chip rather than positive half-cycles. Diodes D1-D4 add output current limiting and prevent large reverse voltages from appearing across the circuit during a short-circuit condition. All four diodes are installed for operation into 8W headphones, giving a maximum output current of about two diodes drops (2 x 0.7V) divided by the emitter resistance (4.7W). For higher impedance headphones, two of the diodes in each channel must be replaced with wire links, halving the maximum current and therefore reducing the chances of accidental headphone damage. The amplifier’s output signal is picked off at the junction of the two 4.7W emitter resistors and fed back to the inverting input (pin 2) of op amp IC1a via resistor R1. Including the output circuit in the op amp’s feedback loop has two important advantages. First, it allows the op amp to servo the output to near 0V with no input signal, accounting for mismatches in the complementary halves of the circuit. It also results in an overall improvement in linearity and reduces crossover distortion. Resistors R1 and R2 set the amplifier gain in the usual manner, giving a gain of +2 (1+ R1/R2) with the 1kW values shown. This is suitable for use with a preamplifier and/or when driving 8W headphones (see the “Tweaking Your Headphone Amplifier” panel for other options). In conjunction with R1, the 1.2nF capacitor (C1) in the feedback path rolls off amplifier frequency response above the audio spectrum. Finally, an RLC network at the output isolates the amplifier from headphone reactance and ensures stability under all conditions. The low impedance of the inductor (L1) at audio frequencies also allows the amsiliconchip.com.au Here’s what a completed inductor looks like (you need two), prior to scraping off the enamel insulation and tinning the leads. plifier to drive difficult loads (down to 8W) with very good results. We’ve used air-cored inductors to avoid the signal distortion that would be introduced by ferrite and iron-cored alternatives. next. Use wire links for R3 & R6 if you’ll be feeding your amplifier from a preamp. Conversely, install 2kW values in these two locations if you’ll be feeding it from a line-level source via a 50kW volume pot. When inserting the LEDs, make sure that you have the flat (cathode) side of the body oriented as drawn on the overlay. IC1’s socket, the four fuse clips, transistors Q1, Q3, Q5 & Q7, the capacitors and connectors CON1-CON5 can all go in next. Take care not to mix up the two types of transistors (BC547 & BC557), and note that the 100mF and 470mF electrolytic capacitors are polarised and must be installed with their positive leads oriented as indicated by the “+” marking in Fig.3. All that now remains to be installed are the 1W resistors, the output transistors and their heatsinks and the two in- Table 1: Capacitor Codes Value 100nF 47nF 1.2nF 100pF 47pF μF Code 0.1µF .047µF .0012µF   NA   NA EIA Code   104   473   122   100    47 IEC Code   100n   47n   1n2    100p    47p ductors. The transistors and inductors require special attention, so fit the 1W resistors first. The two 47W units are positioned in the inductor “centres” and therefore must be mounted vertically, rather than horizontally. Transistor installation The four output transistors (Q2, Q4, Q6 & Q8) are fitted with “micro-U” style heatsinks before installation. To Assembly Assembly is quite straightforward, with all parts mounting on a 134 x 103mm single-sided PC board (code 01111051). Fig.3 shows the details. Begin by installing the 10 wire links, then install the 1N4148 diodes (D1D12). Note that D2, D4, D8 & D10 are only installed if you intend using the amplifier with 8W headphones. For all higher impedance phones, install wire links in these four locations instead (see the “Tweaking Your Headphone Amplifier” panel). Make sure that the cathode (banded) ends of the diodes are oriented as shown on Fig.3. The 0.25W and 0.5W resistors and LEDs (LED1-LED4) can be installed This is the prototype Headphone Amplifier. The final version includes a second headphone socket and has a few other minor changes. Table 2: Resistor Colour Codes o o o o o o o o o o o siliconchip.com.au No.   2   2   8   2   2   4   8   2   2   4 Value 47kW 7.5kW 4.7kW 1.2kW 2kW 1kW 100W 47W 10W 4.7W 4-Band Code (1%) yellow violet orange brown violet green red brown yellow violet red brown brown red red brown red black red brown brown black red brown brown black brown brown yellow violet black gold brown black black gold yellow violet gold brown 5-Band Code (1%) yellow violet black red brown violet green black brown brown yellow violet black brown brown brown red black brown brown red black black brown brown brown black black brown brown brown black black black brown not applicable not applicable yellow violet black silver brown November 2005  31 Tweaking Your Headphone Amplifier F OR THE BEST listening experience, the headphone amplifier can be fed from the Studio Series Stereo Preamplifier described last month. With this combination, a pair of top-quality 32W (or higher) impedance headphones will provide superb performance. Good results can also be obtained with 8W headphones or even two pairs of 32W (or higher) units, if your want to share the experience. In addition, the headphone amplifier can be operated “standalone”, where it connects directly to a line-level signal source (no preamp required). Let’s see how to get the best performance in each case. Using 8-ohm headphones Considerable efforts were made to ensure that the amplifier drives 8W headphones with low distortion. To ensure you get the same results, all eight limiting diodes (D1-D4 & D7D10) must be installed when driving 8W headphones! For higher impedance ’phones, wire links are used in place of D2, D4, D8 & D10 only. What if you own both 8W and 32W (or higher) impedance phones and you want to use all of them with the headphone amplifier – without making changes to the board? Well, while 32W (or higher) headphones can be plugged into an amplifier that’s configured for 8W use, you need to be aware of the potential risks. The amplifier is capable of delivering over 1W into 32W in this case, which is potentially destructive for headphones, your hearing and ultimately the amplifier as well! By the way, we do not recommend increasing the amplifier gain (see “Boosting volume” below) when driving 8W headphones, as this will cause an unavoidable increase in harmonic distortion. With the default signal gain of 6dB, only about 630mV RMS is required at the input to develop the full 200mW into 8W, hence increas- do this, apply a thin smear of heatsink compound to the rear (metal) face of each transistor as well as the mating surface on each heatsink (do not use 32  Silicon Chip ing gain for typical line-level signals is pointless. Boosting volume Using the component values shown on the circuit and overlay (Figs.2 & 3), the headphone amplifier operates with a voltage gain of 2 (6dB), which is more than adequate when the unit is fed from a preamplifier. It should also work fine when driving 8W headphones, regardless of the audio source. However, if you want to connect the unit directly to a line-level source via a volume pot (see “Standalone use” below) and you’ll be using 32W or higher impedance ‘phones, then you may find that the volume is not loud enough, even with the controls wound right up. If after building and testing the amplifier you find that more volume is required, then amplifier gain can be increased to 7.2 (17dB) to allow the full rated output power to be realised in all cases with a 1V RMS input signal. To increase the gain, use the following component values in place of those shown on the circuit and overlay diagrams: R1 & R4 = 7.5kW, R2 & R5 = 1.2kW and C1 & C2 = 100pF. One negative aspect of increasing amplifier gain is an accompanying increase in harmonic distortion. Nevertheless, performance is still excellent, with .0004% THD when driving 600W and .004% when driving 32W headphones, measured at the full rated output power. Standalone use (no preamp) When feeding the amplifier directly from a line-level source, some method of volume control will usually be required. This is easily provided with a 50kW dual-gang log potentiometer, inserted in series with the inputs to the amplifier (see Fig.5). One disadvantage of this scheme is that op amp source impedance var- insulating washers). Affix each transistor to its heatsink using an M3 x 10mm screw, nut and flat washer (see Fig.4), allowing just enough slack so that ies with changes in volume, resulting in higher signal distortion. To offset this effect somewhat, 2kW values can be used for resistors R3 & R6. Accounting for feedback resistance, the inverting input will then see about 2.5kW (R1||R2 + R3), assuming the default 1kW values were used for the feedback resistors. The result is improved matching at the non-inverting input at nominal volume settings. Note that the same 2kW values can be used for R3 & R6 when the amplifier is configured for the higher 17db gain option (see “Boosting volume” above). In this case, the inverting input will see about 3kW. We acknowledge that the 2.5kW 3kW values are only a rough estimation, as the real source impedance can vary anywhere from about 100W to 10kW. Considering headphone sensitivity variation, it would appear to be impossible to establish a “typical” volume setting. Important: when feeding your headphone amplifier from a preamplifier or other low-impedance source, resistors R3 & R6 must be 0W in value (use wire links)! Dual outputs The headphone amplifier includes dual 6.35mm output sockets, allowing simultaneous connection of two pairs of headphones. Two important rules must be followed when using both sockets at once: (1) the headphones must be of the same nominal impedance rating; and (2) the impedance ratings must be 32W or higher. Many listeners will prefer to set their own volume levels and this can be catered for by using headphones with in-line volume controls. Separate volume control boxes are also available from specialist audio outlets. Note that although the sockets are connected in parallel, the jack switch output connects to the first (primary) socket only, so this socket will control the headphone/power amplifier signal routing relay on the Studio Series Preamp. transistor and mounting screw can move up and down in the heatsink slot. Insert a transistor into its holes in the PC board (don’t mix up the two siliconchip.com.au Fig.5: a potentiometer can be inserted in series with the input signals to function as a simple volume control. The metal body of the pot must be connected to chassis earth, otherwise mains hum will be introduced into the amplifier inputs. Fig.6: amplifier total harmonic distortion & noise versus output power into 8W, 32W and 600W resistive loads. When driving 8W and 32W loads, the current-limiting diodes begin to conduct around the 200mW mark, causing a gradual increase in distortion. Once the diodes are fully forward-biased, the output current is aggressively clamped, resulting in an almost vertical rise in distortion. For the 600W case, the amplifier abruptly runs out of voltage headroom at about 130mW and hard clipping is the result. types), pushing it all the way home, so that the mounting screw is all the way down in the heatsink slot and the edge of the heatsink is in full contact with the board surface. If you can’t achieve this, then you’ve fitted the heatsink upside down! Without disturbing the transistor/heatsink assembly, turn the board over and solder the transistor leads. The mounting screw can now be carefully tightened. Don’t overdo it; too much torque will disturb the package/ heatsink position! Winding the inductors The two inductors (L1 & L2) are hand-wound. Each requires a plastic bobbin, about 1m of 0.62mm enamelled copper wire and some electrical insulation tape. Some kit suppliers might provide these items preassembled, in which case you can skip the following instructions. The insulation tape is needed to hold the windings in place while the assembly is fitted to the PC board. General-purpose tape will be wider than the bobbin, but can easily be made to fit by slicing off the unneeded width with a razor blade. Stick the tape down on a smooth, clean surface first to make the job easier. Play out the wire before beginning and remove any kinks. Starting at one of the slots, wind on one complete layer, keeping the wire taut as you go. With one complete layer in place, start winding back over the first layer. In all, 21 turns are required but you’ll need an extra half-turn so that the wire exists at the opposite slot to the starting end (see photo). Wind on two or three turns of insulation tape to hold the windings in place. Finally, scrape the enamel insulation siliconchip.com.au Fig.7: amplifier total harmonic distortion & noise versus frequency, measured with an output power level of 100mW. As is clear from these curves, the amplifier performs much better when driving 32W and higher impedance headphones. Most headphones will reach full output well below 100mW, so you can expect even better performance than these already excellent curves reveal! off the ends of the two leads and tin them before mounting the inductor on the PC board. Hookup For best results, the amplifier should be powered from the low-noise power supply described last month as part of the Studio Series Preamplifier (SILICON CHIP, October 2005). Even if you decide to use a different supply, the guidelines in that article regarding mains wiring, housing and general layout also apply here. An additional step when using the low-noise supply with November 2005  33 Fig.8: this graph plots the amplifier output voltage versus frequency when driven at 200mW into 8W, 32W and 600W loads and with 6dB of gain. As can be seen, the response is ruler flat over the audio spectrum, gently rolling off at the top end at a rate dependent on the feedback network and output loading. this amplifier is to fit small heatsinks to the ±15V regulators (see parts list). Apply a thin smear of heatsink compound to the mating surfaces during assembly, to aid heat transfer. We’ll assume that you’ve already assembled and tested the power supply. All that remains then is to hook up the amplifier’s power and signal inputs. Connect the +15V, -15V & GND outputs of the supply to the headphone amplifier inputs at CON5 using medium-duty, multi-strand hook-up wire. Twist the wires tightly together to reduce noise and improve appearance. Take great care to ensure that you have all of the connections correct – a mistake here will destroy many components on the amplifier board! When installing the unit in a case with a preamp module, the headphone amplifier must not be separately earthed – only the preamp board should be earthed. However, if you’re building a standalone unit (no preamp), then the headphone amplifier’s common (GND) rail should be connected to chassis earth. This is achieved by running a wire from the pad marked “EARTH” on the amplifier board to the main chassis earth point. Do not connect any other part of the circuit or power supply to chassis earth (except the volume pot, see below). For a standalone unit, the volume pot can be wired up next. Use a dualgang, 50kW logarithmic type, connected with audio-quality shielded 34  Silicon Chip Fig.9: this is the crosstalk, again measured for 8W, 32W and 600W loads. Some of the coupling is due to the commoning of the headphone left and right return (ground) leads at the jack plug. The results (although good) would be better if headphones used 4-contact jacks, thus allowing separate grounds for the left and right channels. cable (see Fig.5). The cable can be terminated with panel-mounted RCA sockets on the signal input side and RCA plugs on the output side, which are then plugged into the RCA inputs on the amplifier board. The metal body of the pot must be connected to chassis earth to reduce noise pickup. Do not connect the body to either of the shielded cables! Normally, the front panel will provide the necessary earth connection. If it doesn’t, then connect the pot to a convenient chassis earth point using hook-up wire. Note that solder won’t adhere to the nickel plating on the pot, so remove a small area of the plating with an ink rubber or scouring pad prior to tinning. When used with a preamp, the additional volume pot is not needed. Instead, you simply wire the switched headphone outputs on the preamp to RCA plugs using audio-quality shielded cable. These then plug into the RCA sockets on the headphone amplifier. In addition, the “JACKSW” output of headphone amplifier must be wired to the “SWITCH” input on the preamp Caution! Continual exposure to very high noise levels (including loud music) will cause hearing loss and can cause tinnitus. Hearing loss is cumulative, gradual and almost symptomless! board. This connection will allow the preamp to reroute the audio signal from the power amplifier output to the internal headphone output when a headphone jack is inserted in its socket. Leave the “GND” terminal on CON7 of the preamp disconnected. Testing To check out your completed amplifier, install the fuses and power up. The four LEDs should immediately light up – it not, switch off quickly and check for serious cabling or board assembly problems. If only one LED doesn’t light, then the problem is at least restricted to the associated current source/sink part of the circuit. If all LEDs light as expected, then use your multimeter to measure the voltage between each output and ground. These points are conveniently accessible at one end of the 10W 1W resistors. If all is well, your meter should read within ±2mV of 0V. Next, measure the voltage drop across each of the 4.7W emitter resistors (situated adjacent to the heatsinks). All should measure between about 0V and 100mV, representing a maximum emitter current of about 21mA. Note that this measurement assumes the transistors are idling at room temperature. The reading may be higher if the amplifier has been in recent use and the output transistors have warmed up. OK, we’re done. Now for the best part – the listening test! Enjoy! SC siliconchip.com.au Quality Speaker Kits With a commitment to ongoing research and development, Delta Audio will bring you the latest in technological advancements. sound advice call 08 8295 4271 or visit the website www.kitaudio.com prices start from $995.00 (also available fully assembled) There is no substitute for acoustic excellence XL-02 Custom-made Lithium Ion, NiCd and NiMH battery packs Smart Chargers www.batterybook.com (08) 9240 5000 High-capacity 280mAh rechargeable 9V 2400mAh NiMH AA cells siliconchip.com.au High-quality single cell chargers with independent channels. Charge any combination of NiCd & NiMH AA and AAA cells High-capacity 9Ah rechargeable D November 2005  35 OK, all you budding Billy Hydes and Ringo Starrs out there . . . here’s your chance to own a low-cost “drum kit” which can produce just about any musical sound you can think of – and there’s not a drumskin in sight! You don’t even need to buy a pair of drumsticks! by John Clarke SILICON CHIP MIDI DRUM KIT PART 1 36  Silicon Chip siliconchip.com.au F a similar way to a real drum set, so its operation is more or centuries, drums have been an integral part of natural. music, used in everything from tribal music through There is no doubt that a real drum kit with its highly jazz, rock and blues, right through to symphony polished crash plates, finely crafted drums and the physiorchestras. In many cultures, drums play an integral part cal presence of the instruments all arranged in a group is during ceremonies and religious events. an impressive sight. An electronic drum kit just doesn’t Modern drums tend to be based on instruments that quite have the same appeal because electronic drum kits are used in established cultures. For example, from the are basically uninteresting to look at. Afro-Cuban cultures we have been introduced to the bongo After all, with a real drum kit, you can see the instruand the congas while from the American native Indians ments and even watch them working, particularly with the comes the tom tom. Cymbals of various descriptions have Hi-Hat, the cymbals and the foot-driven drum. originated from Europe, Turkey and China. For these reasons, MIDI drum kits are not often used for Traditionally, drums have tended to be made from live performances but mainly for recording and producing natural products such as carved timber and animal skins synthesised music. while cymbals are usually manufactured from brass. These An electronic drum kit’s claim to fame is therefore not instruments have a charm of their own and produce a its looks but instead its versatility and the significantly unique sound that is dependent on the products used in lower cost than is available with any “physical” their manufacture. drum kit. Modern instruments are made using It is also much easier to transport high-technology materials such as and it produces sound in a form stainless steel, aluminium and its rs ake spe d that can readily be recorded. alloys, plus many types of plastics. an ter pu com • Sound output via a Tables 1 and 2 show the The sound produced by these or synthesiser drum sounds that can be instruments can be tightly ard nd sta the for selectable used with the SILICON CHIP controlled so that each in• Up to 21 instruments kit set drum MIDI Drum Kit when strument has a distinctive a sets Brush, Jazz and Orchestr ing connected to a synthelud and consistent sound. inc 2) DI MI ith 7 extra kits (w e siser located within a Often, these sounds • tim e on the at yed pla • 7 instruments can be musical instrument are recorded in a digiment .7 to select another instru No nt me tru (such as keyboards), tal form so that they ins of l tro • Footswitch con Hat) or via a computer can be played back us(eg, closed and open Top hand plate and foot that has a sound card. ing a synthesiser. The te, pla on ssi rcu pe e lud gers inc its Synthesisers suptechnique for record- • Instrument trig un n tio activa porting the MIDI level te ing is called sampling. pla r ge trig pressure on the 2 standard can also Other synthesiser • Volume level can vary with striking pressed e: wide variation, two com reproduce the exsounds are not recordum vol d pa sor sen for settings tra sounds ranging ings at all but synthe- • Four and a fixed full level gs tin set d an el from 27 to 35 and sised sounds made uslev e um vol ections, patch and from 81 to 87 for the ing oscillators, noise and • LCD shows sensor sel els nn right cha sitioning within left and po standard kit plus the envelope control to recrege sta nd sou le tab jus • Ad d) car nd sou ith (w other drum sets. These ate the required effect. ter pu thesiser or com • Can be used with a syn include the Room, PowOnce the drum sounds s nection (DB15) or serial (DB9) con er, Electronic, TR-808, are recorded or created, we • MIDI out, sound card available Jazz, Brush, Orchestra and can replay them repeatedly ter ver con B US to Sound Effects sets. just by signalling the syntheial ser a • USB operation via Most synthesisers and computsiser to play a particular sample. red     • Plugpack powe ers with sound cards manufactured The data sent to the synthesiser is in after 1995 are likely to support these extra a format called MIDI (Musical Instrument drum sets. Digital Interface) and includes information such as the Of course, if you know enough about music software, you required instrument to be played, its volume and its posican generate your own set of sounds using VST (Virtual tion in the left and right sound stage. Studio Technology) or similar hardware emulators, or add By adding sensors to detect when the recorded “drum” in already created drum patches yourself. sound is to be played, we can drive the synthesiser with the MIDI signal to faithfully reproduce the required drum Presentation sound whenever the sensor is struck. (For a more detailed The MIDI Drum Kit electronics is housed in a plastic box description of MIDI and the way it works, refer to the “MIDI that can be mounted on a stand along with the pad sensors, Theremin” articles in SILICON CHIP, April/May 2005). or used as a freestanding unit with the sensors remotely This is the basis of an electronic drum kit – and the proattached. It includes a Liquid Crystal Display, which can ject presented here, the SILICON CHIP MIDI Drum Kit. It can show the selected drum (or other sound) for each sensor reproduce a vast array of drum sounds without having to pad input, the various settings and the overall volume and use conventional instruments to make the sounds. left to right positioning. Six pushbutton switches are used Drum sounds can be initiated using an electronic keyto change the settings. board to play the instruments or you can use a drum kit. Eight RCA inputs at the side of the box are for the seven The advantage of the drum kit is that it can be played in Features siliconchip.com.au November 2005  37 SENSOR PAD1 SENSITIVITY PEAK HOLD VR1 STORAGE AN2 IC1d, D1 SENSOR PAD2 VR2 EN RB3 RS LCD DATA AN4 IC1c, D2 SENSOR PAD3 RB4 VR3 RB1 RB0 AN1 R IC4 COUNTER CLK IC1b, D3 SENSOR PAD4 VR4 SENSOR PAD5 SWITCHES S1 – S6 AN3 IC1a, D4 VR5 IC3 LED1 AN0 λ IC2b, D5 SENSOR PAD6 VR6 AN5 IC2c, D6 SENSOR PAD7 VR7 RB5 IC5 OPTOCOUPLER AN6 RB2 OUT TO GAMES PORT MIDI OUT IC2d, D7 FOOT SWITCH MIDI INVALID LED IC6 RS232 CONVERTER TO SERIAL PORT Fig.1: the block diagram of our new MIDI Drum Kit. Its operation is explained in the text. sensor pad connections and the foot switch. Other connections are at the rear of the box and are for the MIDI-out, the serial connector, the games port connector and the DC power sockets. One of the DC sockets is for the 9V DC plugpack input and the other for DC output to connect to optically- operated sensor pads. A power switch is included and the LED adjacent to the MIDI socket shows the “MIDI invalid” indication. More about this later. Synthesiser As mentioned before, there is neither a synthesiser nor amplifier within the MIDI Drum Kit – it must be connected to an external synthesiser and the audio output of this synthesiser connects to headphones or to an amplifier and loudspeakers, mixing desk, etc. By far the most common source of a synthesiser is the one inside a standard personal computer or laptop – every sound card has a synthesiser. Another source is an electronic instrument such as a MIDI keyboard. The MIDI Drum Kit can be used with either of these synthesisers. Signals from the MIDI Drum Kit are sent as a series of codes that command the synthesiser to produce sounds. The codes are sent in MIDI format – this is a standardised signal used by the music industry to control synthesisers. We mentioned before the MIDI Theremin article from April 2005. What is different about the drum sounds in MIDI is that they can only be used on one channel (or two channels for MIDI 2) out of a total of 32 channels available for use with MIDI. These are channel 10 plus channel 11 when using the MIDI level 2 standard. In addition, while other channels produce notes of a particular instrument setting, channel 10 produces a sampled sound of an instrument for the note selection instead. 38  Silicon Chip The instrument setting for the other channels becomes the patch number for the drum set. To connect to a MIDI musical instrument, you connect a MIDI lead from the MIDI Drum Kit’s MIDI socket to the instrument’s MIDI input. When connecting to a computer, you have three possible options: (a) use the games port (if the computer has one), which connects directly to the computer’s sound card; or (b) use the serial outlet and connect this directly to a serial port on the computer (again, if the computer has one); or (c) use the computer’s USB port. A games port, which has a DB15 connector, will accept MIDI signals directly. However, many modern computers do not have a games port and some very modern ones don’t have an RS232C serial port either. Those computers will, however, have at least one (and usually several) USB ports. If you do not have a games port or serial port, then the only way to use the MIDI Drum Kit is via a USB port. For this, you will need either a MIDI-to-USB converter or a serial port to USB converter. MIDI-to-USB converters currently cost around $140, while serial-to-USB converters are only about $40, so if you need to use the USB port we recommend the serial-to-USB option. In either case, software will need to be installed in order for the USB ports to respond to the signals sent by the MIDI Drum Kit. There is a difference! When using the serial output from the MIDI Drum Kit to make the computer connection, the signal sent by the MIDI Drum Kit is not genuine MIDI standard. This means that the MIDI signal provided on the MIDI output cannot be used to drive a MIDI instrument when the unit is configured for siliconchip.com.au serial output. In this case a LED lights to indicate that the MIDI output is invalid. The oscilloscope waveforms in Fig.2 show the difference between the genuine 31.25k bits/second MIDI signal (yellow trace) and the serial port’s 38.4k bits/second rate (blue trace). In the latter case, the transmission is completed in a shorter time than for genuine MIDI. Software Software is required when using the computer as the synthesiser source. The main software is the sequencer program. This accepts the MIDI signal sent by the MIDI Drum Kit and directs it to the sound card’s synthesiser. The sequencer also provides many other functions such as the ability to record the music, store it and play it back. Panning from left to right, instrument change, looping and quantisation effects are also available. We used Rave, a freely-available sequencer program that can be downloaded from the internet. The software works with Windows 95, 98, Me, 2000, NT and XP. We will explain how to download, install and use the software in a later issue. Professional sequencers can also be used and these have the advantage that you can edit and create your own sounds. Software for the serial port driver works with Windows 95, 98, Me, 2000, NT and XP. The Serial to USB port driver works with Windows 98 through to XP. justed to match the sensitivity of other sensor pads. Following the sensitivity adjustment, the signal from each sensor plate is rectified and the peak value from the sensor is stored. A microcontroller is used to monitor the stored signals from the sensor plates at the analog inputs AN0-AN6 and the “foot switch” input RB2. If a signal at any of the PAD inputs reaches a predetermined value, then the microcontroller decides that the associated sensor pad has been Block Diagram Fig.1 shows the block diagram for the MIDI Drum Kit. Sensor pads from PAD1-PAD7 are connected to identical circuitry, including a sensitivity trimpot, a peak-hold buffer and storage. The sensitivity adjustment allows any sensor to be adsiliconchip.com.au Fig. 2: these oscilloscope waveforms show the difference between genuine MIDI and the “serial MIDI” for the computer’s sound card. As you can see, the lower trace is completed over a shorter time. November 2005  39 struck and a MIDI signal is produced at output RB5. This is then applied to an optocoupler, the MIDI output socket and the RS-232 converter. The optocoupler provides isolation between the MIDI Drum Kit and the computer connection via the games port. This prevents hum loops forming if the MIDI output is also connected to a synthesiser. The RS-232 converter converts the 0-5V signal from the microcontroller to a nominal ±10V signal for the serial port. When using the serial port connection, the “MIDI invalid” LED lights to indicate that the signal on the MIDI outlet is not able to drive a synthesiser. The microcontroller also drives the LCD and monitors switches S1-S6. Input RB2 of the microcontroller checks if the footswitch is open or closed. +9V +5V PAD1 VR1 20k 100k 100nF 100k Digital circuitry The digital circuitry comprises IC3, IC4, IC5 and the LCD module. IC3 is a PIC16F88 microcontroller from Microchip. It includes features such as a 10-bit multi-channel analogto-digital converter and a serial output that can produce MIDI format signals at 31.25kHz bit rate, with the required stop and start bit. The serial output can also be set to provide the 38.4kHz signal suitable for the serial port on a computer. Either of these two bit rates is accurate when the microcontroller operates at 16MHz and we do this using crystal X1 between 40  Silicon Chip 12 13 D1 4 IC1d 14 A K 100k +5V PAD2 VR2 20k 100k 100nF 100k The circuit The MIDI Drum Kit circuit can be divided into two parts: the analog section (sensor plate input circuitry) and the digital section (the microcontroller, LCD and switches and the MIDI output sections). The circuitry for pad inputs PAD1-PAD7 is identical. The signal source can be either a piezo transducer or an optical sensor circuit (as we shall see later). The signal from each pad is tied to the +5V supply via the full 20kW resistance of the associated trimpot. In each case, the trimpot wiper can be adjusted between the full signal level, when set fully toward the Pad signal input, or to no-signal when the wiper is set at 5V. The signal is AC-coupled with a 100nF capacitor to remove the DC voltage, so that only the AC signal from the sensor passes. The DC level is then set at a nominal +2.5V using a voltage divider comprising two 100kW resistors across the 5V supply. IC1 and IC2 contain operational amplifiers (op amps) wired as peak detectors. Normally, the output sits at the same voltage as the non-inverting input (eg, pin 12). When a signal is applied to pin 12, the op amp’s output varies in response to this and the diode at the output charges the 1mF capacitor to the peak of the signal. When there is no signal at the input, the voltage across the 1mF capacitor will be discharged via the 100kW resistor across it, but not before microcontroller IC3 measures the peak voltage that was present on the 1mF capacitor (ie, at input AN2 of IC3). Immediately IC3 detects this voltage, input AN2 is set to be an output and it is able to discharge the 1mF capacitor via the 2.2kW resistor as soon as the voltage at the cathode of D1 falls. The footswitch input is tied to the 5V supply via a 1kW resistor. This sets IC3’s RB2 input high when the switch is open. When the switch is closed, RB2 is pulled to ground. These levels are also detected by IC3. 10 µF 9 VR3 20k 100k 100nF 100k 8 IC1c A K 100k +5V PAD3 D2 10 IC1: LM324 D3 3 2 1 IC1a A K 100k +5V PAD4 VR4 20k 100k 100nF 100k D4 5 6 7 IC1b A K 11 100k +5V PAD5 VR5 20k 100k 100nF 100k +9V 5 6 PAD6 100k 100nF 100k 7 IC2b A K 100k +5V VR6 20k D5 4 IC2: LM324 D6 10 9 IC2c 8 A K 100k +5V PAD7 VR7 20k 100k 100nF 100k D7 12 13 IC2d 14 A K 11 100k +5V FOOT SWITCH 1k 2.2k SC 2005 MIDI DRUM KIT Fig.2: the circuit looks complex – but compare it to the block diagram and it’s easy to understand the operation. 7805 IN GND OUT siliconchip.com.au +5V 100nF +5V 100 µF 14 2.2k 1 Vdd AN2 RB4 10 10 µF 1 µF RB3 9 4 16 2.2k 3 AN4 RB0 6 10 5 14 6 13 7 12 IC4 4040B Q1 9 11 Q4 CLK Q3 1 µF RB1 7 11 3 2.2k 18 R Q2 6 RS DB7 DB6 2 (JAYCAR 1) EN LCD MODULE DB5 5 7 8 9 1 (JAYCAR 2) 10 +5V 8 S5 S6 S1 S2 S3 10k S4 MIDI INVALID LED1 4 RA5 220Ω 2 A λ K +5V AN3 1 µF 2 IC3 PIC16F88 RB5 220Ω 11 IC5 6N139 λ 3 1 8 8 470Ω 10 µF 100nF 6 17 4 AN0 220Ω MIDI OUT TO SYNTHESISER 5 2.2k 4 16-PIN HEADER 100k 220Ω +5V 16 2 12 5 7 1 µF TO GAMES PORT 9 15 5 2.2k VR8 10k 3 DB4 Q5 AN1 1 µF 2.2k CONT 1 µF AN5 1 µF 2 1 µF 11 2 14 1 OSC2 2.2k 13 OSC1 15 16 1 X1 16MHz 1 µF 33pF 8 33pF 5 4 22k 7 TO SERIAL SOCKET 8 6 1 µF 6 1 µF 5 15 DB9F +9V REG1 7805 +5V 5 D8: 1N4004 LED K K A 4 RB2 Vss D1–D7: 1N4148 3 AN6 1 µF IC6 MAX232 A OUT IN POWER S7 D8 K A 9V DC IN GND 10 µF 10 µF 470 µF 9V DC OUT K A siliconchip.com.au November 2005  41 End-on and side-on views showing the eight inputs (left); above is the DC in/out, games port socket, serial socket, invalid MIDI LED and MIDI output pins 15 and 16. IC3 is supplied with 5V between pins 14 and 5, with 100mF and 100nF capacitors decoupling this rail. The 100nF capacitor reduces high-frequency noise and the 100mF reduces the supply impedance at lower frequencies. The LCD module is driven from IC3, using outputs RB4 and RB3 to control the Enable and Register Select inputs on the module. The data lines are obtained from IC4’s counter outputs, Q1-Q4. IC4 is driven at its clock and reset inputs via IC3 outputs RB0 and RB1 respectively. IC4 is included to expand the two RB0 and RB1 lines into four outputs to drive the data lines for the LCD module. This expansion also allows the circuit to monitor the opening and closing of six switches. Note that the LCD module has eight data lines but we are only driving the upper four bits (DB4-DB7). Data therefore must be sent as two 4-bit blocks in order to drive the display. The enable input and the register select input are control lines to place characters on the display and to set the character position. IC3’s RB0 line provides clock pulses for counter IC4 and simultaneously turns the “MIDI Invalid” LED on or off, as required. It can do this because when the LED is supposed to be off, the clock pulses are so quick that they don’t have time to light the LED. Switches S1-S6 are monitored using IC3’s RA5 input, which is normally held high via the 10kW resistor to the 5V supply. The input will be pulled low if any switch is closed and its corresponding switch connection to IC4 is also pulled low. Since IC3 has full control over the state of IC4’s inputs and outputs, it is able to determine if a switch is closed and which one it is. The output comes from RB5 of IC3. This provides the signal for the MIDI output socket and the games port via optocoupler IC5, along with the serial output via RS232 driver IC6. The signal to the MIDI output socket is fed via 220W resistors, one from output RB5 to MIDI socket pin 5 and the other from 5V to MIDI socket pin 4. In the case of the LED optocoupler, when RB5 turns its LED on, the internal transistors are also switched on and the output (pin 6) is pulled to ground. When the LED is off, the transistor is off and the output is pulled to pin 8 via the 470W resistor. The 100kW resistor from the base of the internal transistor within IC3 to ground speeds up the transistor turn-off. When the circuit is connected to a computer games port, pin 8 of IC5 is connected to the computer’s 5V supply. Note that the grounds are shown with a different symbol to the rest of the MIDI circuit. This indicates that the grounds are different – the transistor side of IC5 is connected to the computer’s ground rather than the MIDI circuit’s ground. The 5V supply on the transistor for IC5 is decoupled using 10mF and 100nF capacitors. IC6 converts the logic levels (0-5V) on the micro’s RB5 output to RS232 voltage levels (±10V) to drive pin 2 on the serial port. With only a +5V supply rail, the MAX232 generates the higher positive and negative voltages required for RS232 communications using two internal charge-pump Specifications Sensor pad volume range: .......................................................................................................... From full to off in typically >120 steps Left to right pan: ............................................................................................................ 128 steps from 0 at full left to 127 for full right Main volume: .....................................................................................................................................from full volume at 127 to off at 0 Sensor pad volume range: ...................................................................................................36dB max range on Wide variation setting, ......................................................................................................................................................18dB range on compressed 1 setting, ................................................................................................................................................12dB range on compressed 2 setting and ...................................................................................................................................0dB range on the Fixed maximum volume setting. Delay from sensor strike to MIDI signal out: ................................................................................................................ typically ~1.2ms Latency (delay between MIDI out signal to sound produced): ......................................................................... depends on synthesiser Repetition rate for sensor pad:......................................................................adjustable from 0 to 255 in steps of 4 corresponding to a ............................................................................................................................. maximum of 224ms or a slowest repeat rate of 4.4/s. ................................................................................................................................. (Typically set at 100 for a repeat rate of about 9/s.) Sensor Threshold: ........................................................... adjustable from 0 through to 127 in steps of 1. Values of less than 5 typical. Current consumption:............................................................................................................................................. 150mA with 9V DC in MIDI out: .......................................................................................... 5mA loop, electrical isolation for games port (31.25k bits/second) Serial out: ............................................................................................................................................RS232 levels (38.4k bits/second) 42  Silicon Chip siliconchip.com.au The case is used upside down with the two stacked PC boards “folded into” the case; the display board held in from above. The case bottom then becomes the front panel. Full constructional details will commence next month. voltage converters. One converter doubles the supply voltage to +10V (nominal) and the other inverts the result to obtain –10V. Four external 1mF capacitors provide the necessary storage and filtering. Power for the circuit is via a 9V DC plugpack. It plugs into one of the DC input sockets and is switched by S7. After passing through polarity protection diode D8, a 9V (nominal) supply is available, as well as a +5V supply, provided by REG1. Another DC socket, wired in parallel with the power input socket, provides a 9V outlet for the optical sensor pad circuitry. It doesn’t matter which socket is used for which. Sensor pads The sensor pad circuitry comprises either a piezo transducer or an optical pickup – see Fig.3. The optical sensing circuitry uses an infrared LED and phototransistor in the one package. Light from the LED strikes the phototransistor which causes it to conduct. When the light is partially or fully interrupted between the LED and phototransistor, the conduction of the transistor reduces depending on the amount of light that is blocked. The LED is supplied with current from the 9V supply. Since this is unregulated, the supply is heavily filtered using a series 470W resistor and 470mF capacitor. This smooths the voltage before driving the LED via another 470W resistor. Diode D9 is included to provide reverse polarity protection. siliconchip.com.au Latency One sometimes troublesome aspect when playing sounds with MIDI is latency. This is the delay from when a sound is played via a keyboard or drum kit sensor plate to when the sound is actually produced and heard. The delay can sometimes be quite noticeable when the synthesiser in a computer is used for playing the sounds rather than the synthesiser in a musical instrument. The latency is largely dependent upon the sound card’s capabilities and the software that’s used with it. We’ll look at this in more detail when we describe using the software in a later issue. However, the latency of the SILICON CHIP MIDI Drum Kit between detection of a sensor plate being struck to sending the MIDI signal is minimal; typically 1.2ms. Generally, it is accepted that an overall 10ms delay is unnoticeable. The SILICON CHIP MIDI Drum Kit can be used with up to eight sensor pads to allow playing seven instruments simultaneously (no, you don’t need seven hands!). The eighth input can be used with a foot-switch that changes the instrument selection. It is ideal for operating the open and closed Hi-Hat cymbals – eg, the closed HiHat sound is generated when the seventh sensor pad is struck and the foot-switch is pressed (closed), while the open Hi-Hat sound is generated if its struck and the footswitch is open. Sounds produced when the sensor pads are struck can be any that are available within the particular selected Drum November 2005  43 TABLE 1: DRUM SET DESCRIPTIONS Patch Number 1 9 17 25 26 33 41 49 57 Drum Set Name Standard Kit Room Kit Power Kit Electronic Kit TR-808 Kit Jazz Kit Brush Kit Orchestra Kit Sound FX Kit Description The General MIDI Standard drum kit. The only kit specified by General MIDI Level 1(35 to 81 inclusive). Similar to the Standard kit but with more ambient percussive sounds. Similar to the Standard kit but with more powerful kick and snare sounds. Made up of sounds emulating those of various electronic drum machines. Analog drum kit that is reminiscent of the Roland TR-808 Rhythm Machine. Jazz-styled set that is nearly identical to the Standard kit. Similar to the Standard kit but with many brush sounds added. An immense collection of concert drums and timpani for orchestral-styled music. A collection of sound effects. TABLE 2: DRUM SETS Patch 1 9 17 25 26 33 41 49 57 Note Standard Room Power Electronic TR-808 Jazz Brush Orchestra Sound FX 27 High Q High Q High Q High Q High Q High Q High Q Closed Hi-Hat - 28 Slap Slap Slap Slap Slap Slap Slap Pedal Hi-Hat - 29 Scratch Push Scratch Push Scratch Push Scratch Push Scratch Push Scratch Push Scratch Push Open Hi-Hat - 30 Scratch Pull Scratch Pull Scratch Pull Scratch Pull Scratch Pull Scratch Pull Scratch Pull Ride Cymbal - 31 Sticks Sticks Sticks Sticks Sticks Sticks Sticks Sticks - 32 Square Click Square Click Square Click Square Click Square Click Square Click Square Click Square Click - 33 Metronome Click Metronome Click Metronome Click Metronome Click Metronome Click Metronome Click Metronome Click Metronome Click - 34 Metronome Bell Metronome Bell Metronome Bell Metronome Bell Metronome Bell Metronome Bell Metronome Bell Metronome Bell - 35 Kick Drum 2 Kick Drum 2 Kick Drum 2 Kick Drum 2 Kick Drum 2 Jazz Bass Drum 2 Jazz Bass Drum 2 Concert Bass Drum 2 - 36 Kick Drum 1 Kick Drum 1 Mondo Kick Electric Bass Drum TR-808 Bass Drum Jazz Bass Drum 1 Jazz Bass Drum 1 Concert Bass Drum 1 - 37 Side Stick Side Stick Side Stick Side Stick TR-808 Rim Shot Side Stick Side Stick Side Stick - 38 Snare Drum 1 Snare Drum 1 Gated Snare Drum Electric Snare Drum TR-808 Snare Drum Snare Drum 1 Brush Tap Concert Snare Drum - 39 Hand Clap Hand Clap Hand Clap Hand Clap Hand Clap Hand Clap Brush Slap Castanets High Q 40 Snare Drum 2 Snare Drum 2 Snare Drum 2 Gated Snare Drum Snare Drum 2 Snare Drum 2 Brush Swirl Concert Snare Drum Slap 41 Low Tom 2 Room Lo Tom 2 Room Lo Tom 2 Electric Lo Tom 2 TR-808 Low Tom 2 Low Tom 2 Low Tom 2 Tympani F Scratch Push 42 Closed Hi-Hat Closed Hi-Hat Closed Hi-Hat Closed Hi-Hat TR-808 Closed Hi-Hat Closed Hi-Hat Closed Hi-Hat Tympani F# Scratch Pull 43 Low Tom 1 Room Lo Tom 1 Room Lo Tom 1 Electric Lo Tom 1 TR-808 Low Tom 1 Low Tom 1 Low Tom 1 Tympani G Sticks 44 Pedal Hi-Hat Pedal Hi-Hat Pedal Hi-Hat Pedal Hi-Hat TR-808 Closed Hi-Hat Pedal Hi-Hat Pedal Hi-Hat Tympani G# Square Click 45 Mid Tom 2 Room Mid Tom 2 Room Mid Tom 2 Electric Mid Tom 2 TR-808 Mid Tom 2 Mid Tom 2 Mid Tom 2 Tympani A Metronome Click 46 Open Hi-Hat Open Hi-Hat Open Hi-Hat Open Hi-Hat TR-808 Closed Hi-Hat Open Hi-Hat Open Hi-Hat Tympani A# Metronome Bell 47 Mid Tom 1 Room Mid Tom 1 Room Mid Tom 1 Electric Mid Tom 1 TR-808 Mid Tom 1 Mid Tom 1 Mid Tom 1 Tympani B Guitar Fret Noise 48 High Tom 2 Room Hi Tom 2 Room Hi Tom 2 Electric Hi Tom 2 TR-808 High Tom 2 High Tom 2 High Tom 2 Tympani C Guitar Cut Noise Up 49 Crash Cymbal Crash Cymbal Crash Cymbal Crash Cymbal 808 Cymbal Crash Cymbal Crash Cymbal Tympani C# Guitar Cut Noise Down 50 High Tom 1 Room Hi Tom 1 Room Hi Tom 1 Electric Hi Tom 1 TR-808 High Tom 1 High Tom 1 High Tom 1 Tympani D Double Bass String Slap 51 Ride Cymbal Ride Cymbal Ride Cymbal Ride Cymbal Ride Cymbal Ride Cymbal Ride Cymbal Tympani D# Flute Key Click 44  Silicon Chip siliconchip.com.au 52 Chinese Cymbal Chinese Cymbal Chinese Cymbal Reverse Cymbal Reverse Cymbal Chinese Cymbal Chinese Cymbal Tympani E Laughing 53 Ride Bell Ride Bell Ride Bell Ride Bell Ride Bell Ride Bell Ride Bell Tympani F Screaming 54 Tambourine Tambourine Tambourine Tambourine Tambourine Tambourine Tambourine Tambourine Punch 55 Splash Cymbal Splash Cymbal Splash Cymbal Splash Cymbal Splash Cymbal Splash Cymbal Splash Cymbal Splash Cymbal Heartbeat 56 Cowbell Cowbell Cowbell Cowbell TR-808 Cowbell Cowbell Cowbell Cowbell Footsteps 1 57 Crash Cymbal 2 Crash Cymbal 2 Crash Cymbal 2 Crash Cymbal 2 Crash Cymbal 2 Crash Cymbal 2 Crash Cymbal 2 Concert Cymbal 2 Footsteps 2 68 Vibra-Slap Vibra-Slap Vibra-Slap Vibra-Slap Vibra-Slap Vibra-Slap Vibra-Slap Vibra-Slap Applause 59 Ride Cymbal 2 Ride Cymbal 2 Ride Cymbal 2 Ride Cymbal 2 Ride Cymbal 2 Ride Cymbal 2 Ride Cymbal 2 Concert Cymbal 1 Door Creaking 60 High Bongo High Bongo High Bongo High Bongo High Bongo High Bongo High Bongo High Bongo Door Closing 61 Low Bongo Low Bongo Low Bongo Low Bongo Low Bongo Low Bongo Low Bongo Low Bongo Scratch 62 Mute Hi Conga Mute Hi Conga Mute Hi Conga Mute Hi Conga TR-808 High Conga Mute Hi Conga Mute Hi Conga Mute Hi Conga Wind Chimes 63 Open Hi Conga Open Hi Conga Open Hi Conga Open Hi Conga TR-808 Mid Conga Open Hi Conga Open Hi Conga Open Hi Conga Car Engine Low Conga Low Conga Low Conga Car Brakes 64 Low Conga Low Conga Low Conga Low Conga TR-808 Low Conga 65 High Timbale High Timbale High Timbale High Timbale High Timbale High Timbale High Timbale High Timbale Car Passing 66 Low Timbale Low Timbale Low Timbale Low Timbale Low Timbale Low Timbale Low Timbale Low Timbale Car Crash 67 High Agogo High Agogo High Agogo High Agogo High Agogo High Agogo High Agogo High Agogo Siren 68 Low Agogo Low Agogo Low Agogo Low Agogo Low Agogo Low Agogo Low Agogo Low Agogo Train 69 Cabasa Cabasa Cabasa Cabasa Cabasa Cabasa Cabasa Cabasa Jet Plane 70 Maracas Maracas Maracas Maracas TR-808 Maracas Maracas Maracas Maracas Helicopter 71 Short Hi Whistle Short Hi Whistle Short Hi Whistle Short Hi Whistle Short Hi Whistle Short Hi Whistle Short Hi Whistle Short Hi Whistle Starship 72 Long Lo Whistle Long Lo Whistle Long Lo Whistle Long Lo Whistle Long Lo Whistle Long Lo Whistle Long Lo Whistle Long Lo Whistle Gun Shot 73 Short Guiro Short Guiro Short Guiro Short Guiro Short Guiro Short Guiro Short Guiro Short Guiro Machine Gun 74 Long Guiro Long Guiro Long Guiro Long Guiro Long Guiro Long Guiro Long Guiro Long Guiro Laser Gun 75 Claves Claves Claves Claves TR-808 Claves Claves Claves Claves Explosion 76 High Woodblock High Woodblock High Woodblock High Woodblock High Woodblock High Woodblock High Woodblock High Woodblock Dog Bark 77 Low Woodblock Low Woodblock Low Woodblock Low Woodblock Low Woodblock Low Woodblock Low Woodblock Low Woodblock Horse Gallop 78 Mute Cuica Mute Cuica Mute Cuica Mute Cuica Mute Cuica Mute Cuica Mute Cuica Mute Cuica Birds Tweet 79 Open Cuica Open Cuica Open Cuica Open Cuica Open Cuica Open Cuica Open Cuica Open Cuica Rain 80 Mute Triangle Mute Triangle Mute Triangle Mute Triangle Mute Triangle Mute Triangle Mute Triangle Mute Triangle Thunder 81 Open Triangle Open Triangle Open Triangle Open Triangle Open Triangle Open Triangle Open Triangle Open Triangle Wind 82 Shaker Shaker Shaker Shaker Shaker Shaker Shaker Shaker Seashore 83 Jingle Bell Jingle Bell Jingle Bell Jingle Bell Jingle Bell Jingle Bell Jingle Bell Jingle Bell Stream 84 Belltree Belltree Belltree Belltree Belltree Belltree Belltree Belltree Bubble 85 Castanets Castanets Castanets Castanets Castanets Castanets Castanets Castanets - 86 Mute Surdo Mute Surdo Mute Surdo Mute Surdo Mute Surdo Mute Surdo Mute Surdo Mute Surdo - 87 Open Surdo Open Surdo Open Surdo Open Surdo Open Surdo Open Surdo Open Surdo Open Surdo - Table 1 (at top left) shows the number of drum sound kits that can be accessed with the SILICON CHIP MIDI Drum Kit. Note that older version synthesisers (pre-1995) may only provide for the standard drum kit. Table 2 (Drum Sets) shows the list of instruments or sounds that can be selected within each drum kit. As you can see, there are more than just a few available! siliconchip.com.au November 2005  45 MIDI Drum Kit Controls When first powered up, the MIDI Drum Kit display shows “MIDI DRUM KIT -PLAY-”. This is the display that should be selected while actually playing the drum kit. Pressing the Port/Cal switch displays the current port setting on the top line and ^ CALIBRATE ^ on the lower line. The port setting is changed from < MIDI PORTS > to < SERIAL PORT > using the left or right arrow switches as shown by the < and > bracketing around the words. The MIDI invalid LED lights when the Serial Port is selected. The Calibration selection is normally only ever used once, after the MIDI Drum Kit has been completed. Pressing the ^ switch calibrates the unit so that the quiescent voltage level for each pad sensor input is registered. This ensures that we get the best sensor response for each pad. To exit from the Port selection and calibration, press the Port/Cal switch again. Note that the four switches arranged in a quad pattern below the LCD are labelled with < > ^ and v. These arrows are also shown on the display when the switches can be used to change the item within the two arrows. So a value or wording located within the < and > brackets can be altered by the < and > switches. The values within the ^ and v brackets can be altered using the ^ and v switches. Pressing the SET switch selects one of several modes that are available to make changes to the way the Drum Kit sounds and works. The first press brings up the PATCH mode. This allows selection of the various drum kit patches available using this MIDI Drum Kit. The top line on the display shows the patch number, showing 1 for Standard, 9 for Room, 17 for Power, 25 for Electronic, 26 for TR808, 33 for Jazz, 41 for Brush, 49 for Orchestra and 57 for Sound Effects. These patch numbers refer to the MIDI instrument numbers. The lower line on the display shows the patch type in words, as indicated above. For example, the display shows < Standard > when patch 1 is selected. The patch is changed using the < and > switches. Note that if your synthesiser does not support the MIDI 2 standard, then only the standard drum set will be played regardless of the patch setting. The next mode is Pan and Volume settings, selected using the Set switch. At left, the word Pan is shown and below this is the Pan value surrounded by the < and > bracketing. The value is changed by pressing the < switch to decrease the value and the > to increase the value. The pan sets the soundstage for the drum kit sound to be produced between the left and right channels. 0 sets the sound fully left, 63 is centred (equal left and right levels) and 127 is fully right. Volume is shown at right with the value directly below this and surrounded by the ^ and v arrows. The value can be changed using these ^ and v switches from 127 (full volume) down to 0 for no sound and any value in between. The next mode selected with the SET switch is the Repeat/Threshold system parameter settings. These are provided to compensate for physical factors that affect the sensor pads. With any hard material that is struck with a drumstick or similar object, it is likely to ring or resonate for some time afterwards. The sensor pads have been carefully designed using materials that do not resonate excessively. However, there will always be some resonance in any design. Resonance will affect the rate at which a sensor pad can be repeatedly struck. To cater for variances in the pads and their resonance, we have included the Repeat setting. This can be set to produce the best repeat rate that is possible. Values are adjustable from 0-255 in steps of 4, corresponding to a maximum of 224ms or a slowest repeat rate of 4.4/s. It’s typically set at 100 for a repeat rate of about 9/s. Use the < or > switches to alter the value. In a similar way, when there are several sensor pads attached to 46  Silicon Chip a common frame, there is likely to be a small amount of interaction between sensors. So if one sensor is struck, other sensors can detect the vibration through the frame. The adjustment of the Threshold value will prevent this interaction from happening. Typically, a value less than 5 will be correct. Use the ^ and v switches to alter the value. Pressing the SET switch again will show the Pad Volume setting. The second line will show Fixed, Vary Wide, Compress 1 or Compress 2. You can change from one to the other with the < and > switches. The Fixed setting means that the drums sounds will be always at their maximum volume when the sensor is struck. The other settings mean that the volume will be dependent on the degree that the sensor is struck. The wide variation setting gives the full 36dB dynamic range of control, while the compress 1 and compress 2 settings give an 18dB and 12dB dynamic range respectively. Basically, the compression boosts the minimum volume level for the drum sounds but does not change the maximum volume level available. Pressing the SET switch will return the display to showing MIDI DRUM KIT -PLAY-. Be certain that this is the setting that you use when playing the drum kit properly. This is because this setting is designed to provide the best response from the pad sensors as they are struck. You can use the other display settings when setting up and changing instruments and patches but be aware that the sensors may not react as well as when the MIDI DRUM KIT -PLAY- is shown. To select the PAD settings, press the SET switch or the < or > switches. The display will show for example <PAD 1> v #50 ^ on the first line. This indicates that the setting for PAD 1 is the “drum” selection number 50. This is the Hi Tom 1 in the standard drum set. The second line on the display shows for example PATCH 1, then a speaker icon and a number. The Patch number indicates the selected patch (1 for standard patch). Initial settings are Patch 1 and the Kick Drum selected for pad 1, the Snare Drum for pad 2, the Hi Tom for Pad 3, the Mid Tom for pad 4, the Ride Cymbal for Pad 5, the Crash Cymbal for pad 6, and the Open Hi Hat and the Closed Hi Hat for sensor 7. The pad 7 selections are changed with the footswitch. The pad selections can be changed to your own preferences using the list provided to make your selections. The speaker icon and number is a diagnostic tool to allow checking which sensor pad is connected to which input. Basically, the number after the volume icon shows the detected volume level that is played by striking the pad. All you need to do is to repeatedly strike a sensor pad and change the PAD selection (with the < and > switches) until the number after the volume icon shows higher numbers other than 0 as the pad is struck. The struck pad will be connected to the currently selected PAD input shown on the display. A right arrow appears also to indicate that a sensor is struck but not necessarily the sensor that you have currently showing on the display. Note that this feature is not easy to use if the Fixed pad volume is selected, since the volume does not change but stays at 127. The PAD settings are adjusted using the ^ and v switches to select type numbers from 27 through to 87. These select the “drum” sound required for the selected pad. The PAD selection is changed with the < or > switches selecting PAD 1 through to PAD 7. PAD 7 is shown as either 7a or 7b and is again selected using the < or > switches. The 7a pad “ drum” selection is the “drum” selection when the foot switch is open and the 7b selection is when the foot switch is closed. You can return to the MIDI DRUM KIT -PLAY- display by pressing the SET switch and return to the pad settings with the < or > switches without having to cycle through all the other settings that are available. Note that the pad number seen on the display will change up or down, depending on the < or > switch that is pressed. siliconchip.com.au 1N4004 9V DC IN PIEZO TRANSDUCER A RCA PLUG K 470Ω INTERRUPTOR 470Ω PIEZO PIEZO SENSOR Fig.3: the two types of sensors, as described in the text – the simple piezo sensor (above) and the more complex (but better) optical sensor (right). 9V DC OUT (THRU) 470 µF A C K OPTICAL SENSOR 1N4004 A Set, as shown in Table 1. Output volume level is dependent on how hard the sensor pads are struck. Alternatively, there are settings that compress the volume level or one that only plays at the maximum level. In this latter case, the overall volume is then dependent on the master volume setting and the volume setting for the amplifier connected to the audio signal. The sound duration is fixed and is set by the sample within the synthesiser. The sensor pad designs use readily available components that can be obtained from electronics stores and your local hardware shop. In its simplest form, a piezo transducer can be mounted onto a length of plastic tubing and wired to an RCA plug lead. The tube is then tapped with a fingernail, thimble or drumstick to trigger the sound production. This is an ideal sensor pad for stick, click, metronome, whistle and even cymbals or drums if you wish. A piezo transducer is also used in the percussive sensor. This transducer is mounted onto a semi-circular shaped piece of MDF (Medium Density Fibreboard) and this board is then attached to a light-duty frame using plastic clamps. The pad is ideal for virtually all types of instruments as it can be mounted in space (on the frame), in the positions required for ease of playing. The sensor pad must also be struck with a stick or similar hard object. This type of pad has the advantage that it is very easy to build. The percussive sensor pad does, however, have the K RCA PLUG λ λ OPTICAL SENSOR E SENS1 (TOP VIEW) A E K C disadvantage that it produces a sound of its own when tapped. This is normally drowned out by the actual drum sounds. It may, however, be a problem and so we have added settings that can play the drum sound at a louder level, even when the sensors are tapped very lightly. This keeps the unwanted sound at a low level. In addition, the pad can be covered with some vinyl or similar material to deaden the percussive sound or alternatively, the sticks can be rubberised. Such damping will also mean that the pads will have to be hit harder to develop the same sound level from the synthesiser. High-precision sensors can also be made for the MIDI Drum Kit and are based on optical sensing. They can be operated by palm of the hand, your feet or fingers. The optical pads provide a high degree of play control and good volume variation with different pad pressure. They also do not make any noise of their own. They have the disadvantage of being more complex to build and if they are to be mounted on a stand, it must be of high strength to prevent movement when the sensors are played – particularly if the musician gets a little carried away . . . Next month we will describe the construction of the MIDI Drum Kit, making the sensor pads and setting it up. That will include downloading and installing the required software and SC we’ll also describe how to use it. The two types of sensor: at left is the optical variety and at right the piezo model. The optical type, though more complex to construct, has several advantages. siliconchip.com.au November 2005  47 SILICON CHIP Order Form/Tax Invoice Silicon Chip Publications Pty Ltd ABN 49 003 205 490 www.siliconchip.com.au PRICE GUIDE: SUBSCRIPTIONS YOUR DETAILS (Note: all subscription prices include P&P). 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SUBSCRIBERS QUALIFY FOR 10% DISCOUNT ON ALL SILICON CHIP PRODUCTS* * except subscriptions/renewals Qty Item Price Item Description Subscribe to SILICON CHIP on-line at: www.siliconchip.com.au Both printed and on-line versions available Total TO PLACE YOUR ORDER P&P if extra Total Price BUY MOR 10 OR ISSU E BACK ES A 1 0 & G ET DISC % OUN T $A Phone (02) 9979 5644 9am-5pm Mon-Fri Please have your credit card details ready OR Fax this form to (02) 9979 6503 with your credit card details 24 hours 7 days a week OR Mail this form, with your cheque/money order, to: Silicon Chip Publications Pty Ltd, PO Box 139, Collaroy, NSW, Australia 2097 11-05 WOLLONGONG HAS MOVED! PSP Memory Cards Frustrated with the tiny 32MB card that came with your PSP? Take full advantage of this awesome piece of hardware! With a 512Mb card you can hold around 8 hours of MP3 audio or 2 hours of H.264/MPEG4 video for playback on your PSP! DOUBLE THAT ON A 1GB CARD! OPEN 7 DAYS 512MB Card Cat. 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It can store up to two hours of MP3 music or four hours of WMA music. It has 5 inbuilt equalisation settings for optimum sound and can Cat. GE-4001 operate just as a USB $ .00 flash disk. Was $149 79 2 Watch Movies, Listen to Your Favourite Songs on this 1GB MP4/MP3 Player SAVE $70 •IEEE 802.11g wireless network compatible. Interoperation with IEEE 802.11b 11Mbps networks. •64 / 128 Bit WEP encryption. •54Mbps high speed transfer rate. •40 - 100m indoor range. •100 - 300m outdoor range. Cat. YN-8066 •Low power consumption. $ .95 •Plug and Play compatible. •Compatible with Win98/SE/2000/ME/XP 69 USB 2.0 Wireless Network Adaptor •54Mbps Cat. YN-8067 $ .95 •54Mbps 80211G SAVE $20 Was $89.95 Cat. YN-8068 $ .95 69 WiFi Hot Spot Finder Check for the presence of wireless network hotspots without the hassle of unpacking & booting-up your notebook computer. This key-fob sized device will tell you when you are in a WiFi capable location and indicate the strength of the signal at the press of a button. Will also detect the signals transmitted by wireless surveillance cameras they may be observing. •Size:75(L) x 37(W) x 10(D)mm. Cat. XC-4885 •2 x CR2032 batteries included. $ .95 39 USB Bluetooth Dongle Class 2 SAVE $5 Supports Windows 98SE, 2000, & ME. Get short range wireless connectivity with mobile phones, PDAs, some keyboards and mouse Cat. XC-4890 products with this USB Bluetooth $ .95 dongle. Was $49.95 44 89 Wireless Networking Book Covers both the Windows and MAC environments. It includes the basics of wireless networks and the "nuts & bolts" of how to build your own wireless network. Cat. BP-7100 $ .95 49 Wireless Internet Antenna Having trouble getting unwired? This wireless modem antenna replaces the existing 'rabbit ear' on your wireless broadband modem and boosts the signal to improve coverage. It can also improve performance in difficult areas. The antenna can be mounted inside the house or in a modem not included protected outside location for optimum reception. Supplied with Cat. AR-3274 N type to MCX lead & mounting bracket. $ .95 •Size 135(W) x 160(H) x 30(D)mm. 129 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Multi-Network Cable Tester TV/Video Capture Systems N e t w o r k Te s t e r s Network Cable Tracer Quick and easy! Test UTP, STP, Coaxial, and Modular network cables by automatically scanning the wires for continuity, mis-wiring and polarisation. It uses a remote terminator for testing of installed or uninstalled Cat. XC-5075 $ .95 network cables. Was $69.95 Invaluable for technicians! This tone generator is a practical network installation and troubleshooting tool. The insulated inductive pickup amplifies the tone signal, and the tracer can also be used to check Cat. XC-5083 telephone line status $ .00 (ring, busy, idle). SAVE $30 39 129 Multi-Network Cable Tester with Pin-Out Indication Intelligent Network Cable Tester Visual indication! Suitable for use with UTP, STP, Coaxial, and Modular network cables, it features two LED bar-graphs to indicate pin connection. You can then quickly see any incorrect Cat. XC-5076 connections. $ .95 This versatile tester will check your cables for continuity, crossed wires etc, and help you identify cables without continually walking from each node to the hub. Each kit is supplied with 4 specialised terminators with unique I.D.s. 49 Network Cable Tester for RJ12, RJ45, and USB Cat. XC-5077 $ .00 79 2.5" IDE - USB 2.0 Hard Disk Drive Case Massive portable storage! Instantly add gigabytes of storage to your PC or notebook. You can use any 2.5" IDE HDD, and then plug it into your USB 2.0 port for super fast backup, transfer, and storage. Includes carry pouch, Cat. XC-4678 $ .95 cable, and drivers (only required for Win98). 49 1.3 Mega Pixel Mini Digital Camera 169 Cat. XC-5086 $ .00 149 Notebook Docking Station No more cable tangles! Leave your peripherals connected to the dock, and just plug/unplug a single Cat. XC-4860 cable! Includes 4 port USB 2.0 hub, $ .00 Ethernet, serial, and 2 x PS/2 connections. 139 100k Mini Digital Camera Pocket sized at just 60 x 43 x 17mm, with a maximum capacity of 80 photos. Cat. QC-3190 Was $29.95 $ .95 24 SAVE $10 USB 2.0 HIGH DEFINITION Terrestrial TV Tuner for PCs Top quality reception! No need for physical hardware installation, just plug it into your USB 2.0 port for HDTV. It operates in enhanced 16:9 format with software supplied for DVD making and manipulation. See our Cat. XC-4814 website for system requirements. $ .95 NOT AVAILABLE IN NEW ZEALAND 249 Convert all your old VHS tapes and camcorder cassettes to DVD! XPERT DVD Maker converts on the fly, so there is no need for excessive amounts of free disk space. All you need is a DVD burner and you can store your memories forever! Was $149 SAVE $50 Cat. XC-4811 $ .00 99 USB 2.0 DVD Maker No more fading memories! Transfer all of your VHS, Betamax, and camcorder tapes to DVD using your computer’s DVD burner. With editing software to add colour and transitional effects, as well as sound tracks. Supports composite Cat. XC-4809 SAVE $ .00 & S-Video inputs & PAL or $20 NTSC sources. Was $149 129 SAVE $5 USB 2.0 Video Capture Box 49 Streaming full resolution video on your PC! Preview, record and playback video, or burn to CD or DVD. This is a great way of making DVDs if you own an analogue video Cat. QV-3090 camera. Includes capture and editing $ .00 software, supports MPEG1 & MPEG2. 49 The laser image changes as you turn the tip of the pen from arrow, to a line or to the normal red laser dot. Use the laser line to emphasise Cat. ST-3106 $ .95 a word, direct movement using the laser arrow or simply point out aspects of your presentation with the conventional red dot. Made from sturdy metal and uses 2 x AAA batteries (not included) 128MB 5 in 1 Digital Camera Possibly the most versatile digital device around! Cat. QC-3226 It measures just 72 x 17 x $ .00 15mm, but what you can’t tell by looking at it, is that it actually has five different Digital Camera Pen SAVE functions. A tiny digital camera! $30 It operates as a: It looks just like a pen, but it •300k pixel digital camera houses a small CMOS sensor, and SAVE storing up to 2000 images. memory $69.05 •100k pixel •up to 20 mins storage. to capture •Voice recorder with up to 2 hrs storage. up to 36 images! Images are Cat. QC-3380 •Web camera when connected to a PC. Cat. QC-3224 $ .95 downloaded via the serial port. $ .95 •128MB USB flash disk for data storage. Was $79.95 Powered by an internal lithium battery charged by the USB port. Was $259 MP3 Player Back-Phones These might look like any other quality stereo back-phones, however these little beauties 300k Pixel SurfCam USB Web Camera actually include an impressive MP3 Video conferencing and more! player, battery and all the It uses a 300k pixel colour controls you need to SAVE CMOS sensor with auto $6 listen to your favourite exposure and white balance music. The 128MB on-board for optimum performance. Software memory will hold around two hours included for creating greeting cards of music and run for about Cat. GE-4002 and photo albums. Cat. QC-3223 $ .00 15 hours on one charge of the $ .00 SAVE internal battery. Was $99 Was $35 $30 69 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 HDTV on your computer! Watch high or standard definition TV on your PC! It supports widescreen (16:9) and standard (4:3) aspect ratios. •PCI Card version Was $179 Cat. XC-4819 NOT AVAILABLE IN NZ $ .00 XPERT DVD Maker Even checks USB! Check the condition of your RJ-45, RJ-12, and USB cables. Press the test button, and the 13 LEDs indicate any open or short circuits, and cross wiring. SAVE Was $119 $40 Great photos anywhere! Take it with you anywhere, anytime! It operates as a digital camera on its own, or a streaming web cam when connected to a PC. It gives you great 1280 x 960 pixel images. Measures just SAVE 86x31x27mm. Was $59 $10 HIGH DEFINITION Digital Terrestrial TV Card for PCs INTERNET> www.jaycar.com.au 189 29 99 Laser Pointer with Line and Arrow 29 Laser Pointer with Power Point Remote Control Power Point presentations are a great way to get information across to a large audience. This excellent device incorporates "Page Up" & "Page Down" buttons. The combination allows you to move around the room and still run your presentation and point-out items of interest. This device has Cat. ST-3108 a transmission range over 15m. $ .95 You can’t go wrong. 49 3 2.4GHz Wireless Audio Video Senders Watch cable TV all over the house! Send a signal from a DVD player, settop box etc., to another room, without the use of any cables! You can use as many receivers as you like, without degrading signal quality. Each unit comes supplied with stereo audio and video transmitter and receiver, mains plugpacks & RCA cables. Transmission range is up to 100m, but depends on the type of construction materials used. Cat. AR-1832 SAVE $ .95 Was $99 $29.05 69 Extra receiver to suit Cat. AR-1833 $ .95 SAVE $19.05 49 Cat. AR-1833 Was $69 SAVE $49.05 Cat. AR-1831 $ .95 69 SAVE $19.05 3 Piece Surround Sound Add - On Enjoy the surround sound experience. The centre SAVE speaker contains $60 a screened 4" mid / woofer & 2" tweeter with a 6 ohm impedence. The two rear Cat. CS-2465 speakers contain a 4" full range speaker $ .95 with a 4 ohm impedence.Was $99.95 39 Stereo Wall Speaker This stereo speaker is ideal for home installations in entertainment areas such as verandas, rumpus rooms, etc. It consists of a 6.5" woofer with dual voice coils and a pair of 13mm dual cone Cat. CS-2445 $ .95 Mylar tweeters Analogue to Digital Audio / Composite to S-Video Converter Play music from any USB Flash Disk. The system looks like a pair of classy portable speakers but features an in-built MP3 decoder that will play MP3 files straight from any Flash Disk. The speakers are small, light, and stylish and can go just about anywhere. The system also incorporates an external input so you can play other devices such as CD players or Walkman etc. Operates on 9 VDC and a mains plug pack is included. Cat. XC-5161 $ .95 USB 2.0 Surround Sound Simulator for Headphones Add a new dimension to your gaming! This tiny device takes your regular stereo signals and transforms it into simulated surround sound. It makes your games, CDs, and DVDs come to life. Also has a graphic equaliser and room simulation. Cat. XC-4882 $ .95 Measures 30(W) x 80(L) x 20(T)mm. 29 Video conversion works both ways! This processor converts analogue to digital audio, as well as composite video to S-video and vice versa. It offers optical and coaxial digital audio outputs, which supports the sync record function. 9VDC power supply included. Speaker / Source Control Wall Plates Control the music around your home! With these inexpensive units, you can control volume, select speakers, and even sources! It allows you to wire your home with sound, while maintaining flexibility. See website for full details. Source and Speaker Switch Select between two sources Cat. AC-1677 $ .95 and distribute to one or both pairs of speakers. 19 Composite Video to VGA Converter This neat device converts all region video signals into a non-interlaced VGA signal for monitors. With features such as, an on screen display and a slim line remote control, this converter box is user friendly and easily connected to your PC, video Cat. XC-4872 source, and video game consoles $ .95 without any software installation. In Wall Speakers 99 2 Way Speaker Switch Switch between two speaker Cat. AC-1679 $ .95 pairs quickly and easily. 19 70W 12 Step Stereo Loudspeaker Attenuator Attenuates by up to 46dB on an 8-ohm system for tailored listening Cat. AC-1685 levels. $ .95 39 LONG DISTANCE VIDEO TRANSMISSION – WITHOUT SIGNIFICANT SIGNAL LOSS Use video baluns and Cat5e cable to get much longer cable runs than possible with regular cables. Composite Video Cat 5 Video Balun S-Video Cat 5 Video Balun LCD Virtual Goggles Take the cinema screen with you! Enjoy private viewing of your TV/DVD/VCR or games console with these lightweight goggles. So portable they can be used in a car to enjoy DVD player entertainment, or connect it to a video games console such as PLAYSTATION, XBOX, etc. Supplied with cables & power adaptor. 800 x 225 (180,000) pixel resolution. Cat. QM-3790 SAVE $ .00 Was $399 4 49 89 A great mounting solution! If space is limited, or you simply don’t want free standing speakers, then these are a great option for you. 8 ohm impedance allows them to be used in an array of applications. Supplied with attractive white baffle covers. 2 Way Cat. CS-2440 $99.00 3 Way Cat. CS-2442 $149.00 $50 Sleep soundly! They are designed for use in noisy environments such as aircraft or cars reducing background noise by as much as 15dB. Powered by two AAA batteries (included), they come with a 1.8m lead terminated with a 3.5mm stereo plug. Cat. AA-2054 $ .95 Cat. AC-1612 $ .95 69 Portable USB MP3 Player 89 Noise Cancelling Headphones 89 Extra receiver to suit Cat. AR-1831 Was $89 A digital camera for under $200! This easy to use camera fits in the palm of your hand. The recorded video can be transferred to a computer for editing or simply viewed directly on any TV with AV inputs. Features include a 3.1 Megapixel software resolution for stills, 1.5" colour LCD screen, 5 layer glass lens; 32MB internal memory, SD/MMC expansion slot, 4 x digital Cat. QC-3230 SAVE zoom, internal microphone $ .00 $20 and lots more! Was $199 179 As Above but with Remote Control Extender With the addition of an IR remote control repeater you can change the channel of the source device etc from the Cat. AR-1830 other room. $ .95 Was $139 Mini Digital Video Camera 349 Video and audio! Transmit video and audio up to 300m colour, or 600m B&W. •75(L) x 55(W) x 25(H)mm. One Cat. QC-3424 required at each end. $ .00ea 95 RGB Cat 5 Video Balun Ideal for home theatre! Send RGB up to 300m without degradation. •110(W) x 77(D) x 24(H)mm. One Cat. QC-3429 required at each end. $ .95ea 79 Huge distance! Transmit your S-Video signals up to 300m. •69(W) x 25(D) x Cat. QC-3423 22(H)mm. •One $ .95ea required at each end. 39 VGA Cat 5 Video Balun - Pair Unbeatable! Transmit your VGA signals up to 135m - much further than otherwise possible! •110(W) x 77(D) x 24(H)mm. Supplied as a Cat. QC-3428 transmitter and $ .95 receiver pair. 149 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Great New HDMI Leads and Accessories The latest technology! The High Definition Multimedia Interface (HDMI) provides high quality signals for the best reproduction quality. HDMI Connecting Cables Male to male connection Cat. WQ-7400 1.5m Cat. WQ-7402 3.0m Cat. WQ-7404 5.0m $39.95 $49.95 $64.95 HDMI to DVI Cable Cat. WQ-7406 3.0m $39.95 HDMI Adaptors Cat. PA-3640 HDMI Socket to Socket Cat. PA-3642 HDMI Plug to DVI-D Socket Cat. PA-3644 HDMI Plug to DVI-D Plug $14.95 $14.95 $14.95 HDTV Distribution Amp Now you don’t need multiple set top boxes! Now you can have top quality TV in more than one room. This unit distributes HDTV signals up to four ways without losing Cat. AC-1678 signal quality. Powered $ .00 from the supplied mains plugpack. 299 Plasma Screen Bracket Thie heavy duty wall mounted bracket is suitable for mounting plasma screens of up to 75kg. In situations where tilting is required such as in gyms, clubs and bars, the bracket is able to tilt up to 20 degrees. Specifically designed for 26" to 63" flat screen monitors & TVs the bracket allows the Cat. CW-2816 screen to be mounted a mere $ .95 10.1cm away from the wall. 149 Pre-Programmed Smart TV Remote Pre-programmed for over 600 models this remote operates the main functions of your TV and features large, easy to read buttons. Cat. AR-1703 $ .95 Learning and Programmed 5 in 1 Remote This remote is preprogrammed for over 25,000 pieces of equipment and will learn any other infrared code that you need. It also features teletext. Was Cat. AR-1714 SAVE $ .95 $57.95 34 Simple solution! Optical signals cannot be electronically switched, but this switch box provides a solution. Four inputs (1 x 3.5mm, 3 x Toslink), 1 Toslink output. $23 Headphone Adaptor Set Cat. AC-1675 $ .95 19 Contains virtually every popular headphone/headset adaptor and an extension lead. Cat. WA-7099 $ .95 5-Input Mixer This stereo mixer features a removable crossfade slide control, LED VU meters, dedicated gain controls for each channel (including the master output) and cue level and mixing controls. A talk over function is also included and the channel to be cued can be selected with a centrally located rotary switch. See website or our catalogue Cat. AM-4210 for full specifications $ .00 169 Parabolic Microphone Move over 007! This great unit amplifies sounds from afar, as well as an integrated monocular viewer with 10 times magnification, and a 12 second digital voice recorder. 14 UHF / VHF Indoor TV Antenna / Amplifier How’s your TV reception? This antenna has a built-in amplifier with 24dB gain on VHF, and 20dB gain on UHF with gain control. Powered directly from 240V mains. See website for details. Limited qty. Was $44.95 SAVE $5 Cat. LT-3135 $ .95 7 Metre Retractable Coaxial Lead Cat. AM-4100 $ .95 89 Desktop Broadcast Microphone Ideal for PA applications! It features a flexible 165mm gooseneck attached to a sturdy aluminium base. It has a "push to talk" and "lock" switch for convenience. Cat. AM-4088 $ .95 59 No more tangles! The cable retracts into the holder when not in use. Includes gender change adaptor. Cat. WV-7368 $ .95 14 Brushed Aluminium 64 CD Case Strong and stylish! Finished in brushed aluminium, it protects your CDs as well as looking great. Cat. AR-1497 CDs not $ .95 included 19 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Affordable at last! Spectacular U.S. Stock Purchase All Audiophiles know that ribbon tweeters are the ultimate speaker for smooth high (and very high) frequency performance. Don’t Miss Out! Unfortunately, a good ribbon tweeter can cost between $100 and $500 - to thousands for some custom German ones. Even high-end enclosure manufacturers all opt for dome tweeters simply because "ribbons" add too much to system cost. Jaycar have made a massive stock purchase from a major US organ manufacturer who makes both pipe and electronic organs. They are an 80+ year old company and we cannot tell you who they are! They are restructuring their production of their high-end organs and their stock of ribbon tweeters has been sold to us far, far below the 10,000+ factory gate price! Their massive loss is your gain. The tweeter is made in Japan by the venerable manufacturer, Foster. The device itself has multiple ribbon "diaphragm" components in same phase configuration. There are two basic types of ribbon tweeters, static or dynamic type. This product is the dynamic type which has conventional impedance 8Ω and is more efficient. Each speaker is supplied with a datasheet and securely packed. Even if you do not have any specific need for a ribbon tweeter at the moment, we strongly urge you to consider purchasing it for future use. At the price we are offering, we expect OEM (manufacturer) interest. As it is a distress stock buy, quantities are limited. On many occasions in the past we have warned customers of this and the slow ones miss out. Finally, we think that technically, two tweeters per enclosure would be the way to go. They should not be overdriven. Note also the fairly high crossover frequency. In keeping with this suggestion, we have a special price for a set of 4 pieces. Type: Regular-phase 100mm ribbon tweeter Power: 20 Watts RMS (cont), 50W max. SPL: 92dB/Watt. Freq Resp: 6K-40KHz +/-2dB (SUBLIME!). Impedance: 8Ω. Crossover Frequency: 6,400Hz (12dB / Octave). 21 4 Way Optical Switch Box RIBBON TWEETERS 39 Normally a speaker of this quality would sell for over $100. Because the factory’s loss is your gain we are offering this product for only $39.95 each, or a set of 4 for only $136 – only $34 each! You will KILL yourself if you miss out and you will if you delay. Cat. CT-2023 $ .95EA 39 or buy as a set of 4 for $136.00 That”s only $34 each! UHF Phased Array TV Antenna Digital TV ready! •Band F IV/V, 470 to 862MHz. •UHF Channels: 21 to 69 •Maximum gain: 12dB. •Includes F type Balun. •Used for horizontal or Cat. LT-3138 vertical polarisation. $ .95 •470mm x 810mm. Available in selected areas. Check your local store for availability. 64 5 100 Piece Clay Poker Chips This poker SAVE set is $5 immaculately presented in an aluminium case. The set consists of 100 authentic high quality chips 25 x red, 25 x white, 25 x blue and 25 x black two - toned clay chips, a deck of laminated playing cards and 5 dice. Invest in a professional set that will sure to be the envy of your friends. •Individual chips Cat. GT-3572 weigh a genuine 11.5 $ .95 grams each.Was $34.95 29 Mini Black Jack Set Enjoy some Las Vegas style fun with this mini blackjack set. •Chips & chip rake •Card dispenser with cards Cat. GT-3560 •Miniature table approx. $ .95 260(L)x160(W)x40(D)mm 19 Bring The Casino Home! A genuine 11.5grams each! When you hold them you can really feel how good the quality is compared to the cheap plastic chips you find in toy stores. Contains four sets of 25 black, blue, red and white chips. Chip size: 40(dia) x3(H)mm Was $79.95 Cat. GT-3574 59 $ .95 Bring the casino action onto your TV screen. This device contains 12 popular casino games including Caribbean Stud poker, Baccarat, Blackjack and Slot machine. Was $49.95 59 Suspended World Globe with Pen & Pen Holder A fascinating gift. The electromagnetic levitating globe floats in thin air and seems to defy the laws of Cat. GG-2170 gravity. $ .95 Get to the truth fast with this handy little lie detector. Ask your suspect a question and if their answer is not truthful, the machine will know and give a low score, now you can find out if your fishing buddies are really telling the truth or if Cat. GT-3060 your boyfriend truly does think your $ .95 bum looks OK in those jeans. Go-Ballistic - An Exciting Target Game The aim of the game is to fire the ball through the centre "Bullseye" and score points. The level of excitement is increased by the inbuilt voice chip that urges you on to greater heights. 39 SAVE $10 29.95 $ Small, sleek, and stylish. A unique rubber stand moulds to any shape to suit all surfaces. Clock face size is 81(H) x 55(W)mm. Was $17.95 SAVE $3 Cat. XC-0216 14.95 $ Oscillating Message Board This futuristic unit displays a message, time, or date, without a solid display. It uses a fast oscillating arm with LED's.Using precision timing, and clever calculations,it appears to display the message in thin air! It can be programmed to cycle through the user Cat. XC-0198 programmed messages, or simply $ .95 display the time and date. New Improved Fart Machine Choke A Chook This well constructed 1:420 scale R.C model of the 19th century 'Cutty Sark' is a must for collectors and boating enthusiast. With a five metre remote control range and efficient use of battery power, this product will guarantee hours of fun for the Cat. GT-3415 whole family . $ .95 •Size: 205 x 125mm Cat. GT-3577 69 39.95 Remote Control Sailing Ship 3 in 1 Poker This palm sized handheld game boasts exciting sound effects and features 3 playing modes of Texas Holdem. Was $39.95 Desk Clock with Alarm and Calendar 29 $ SAVE $10 14 19.95 Cat. GT-3062 39 39.95 $ $ Novelty Pocket Lie Detector This is one tough cookie! Smash it, crash it and it still comes back for more. Every panel on the car is detachable and can miss-align, fly open or even come off in a crash. Suitable for ages 10 up. Red model also Cat. GT-3200 available GT-3202 $ .95 •Features a regenerate button Cat. GT-3554 A genuine 11.5grams each! You can really feel how good the quality is compared to the cheap plastic chips you find in toy stores. Contains four sets of 25 black, blue, red SAVE and white chips. $10 Chip size: 40(dia) x Cat. GT-3571 3(H)mm $ .95 Was $24.95 Become the next Australian Poker Champion! It boasts real casino styled sounds and a two pot limit with three modes of playing styles. •Batteries included Cat. GT-3578 59 SAVE $20.90 100 Piece Clay Poker Chips SAVE $10 Texas Hold'em Poker Game Keyring 200 Piece Clay Poker Chips BUY 2 FOR $99 6 SAVE $20 SAVE These are fine looking clay $20 chips that feel just like the real thing. They are loaded into a real wooden carousel with a 'lazy susan' style base, which also comes with two decks of playing cards. There are 200 chips in total, 50 each of black, Cat. GT-3570 blue, red, and white colours. $ .95 Was $79.95 Remote Controlled High Speed Demolition Derby Jeep Was $49.95 12 in 1 Casino Game Console 200 Piece Clay Poker Chips Our best fart machine yet! With twice as many realistic sounds as our regular model, this new fart box is sure to shock everyone at a party with disgusting Cat. GH-1087 realism. $ .95 Relieve stress with a bit of violence! This annoying chicken dances around and squawks. Funny for about one second! Grab him by the throat and he screams and gags. Funny forever! (not recommended for children) •Approx 300mm tall. Cat. GT-3095 •Requires 4 x AA $ .95 batteries (not incl) 19 Remote Controlled Hovercraft 29 Nicky the Remote Control Clownfish Nicky the Remote Control Clownfish will SAVE add colour and delight to $10 your fish tank. It is a realistic looking fish which can be manoeuvered left, right, forwards or backwards. Requires 3 x AAA batteries Cat. GT-3225 (not included) $ .95 Was $29.95 19 This is really a very shallow-draft boat designed to look like a hovercraft. It's not designed to operate on land, but on the water, it is a speedy little craft that is very manoeuvrable and will zip around the bath tub, pool or fish pond at surprising speed. The craft has an internal battery that is charged from the battery box supplied with the package. Cat. GT-3410 Requires 6 x AA batteries available $ .95 separately. Use our SB-2425 4 packs. 29 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Ionic Shoe Dryer Eliminate odours from your shoes with this innovative Ionic Shoe Dryer. As you wear your shoes, the dampness of your feet as well as weather conditions can cultivate the growth of mould, fungus and other assorted microbes. Controlled by a micro-computer, it adopts an advanced "ionic breeze technology" Cat. GH-1194 which will neutralize the odour and $ .95 eliminate the nasty growth. 29 Ionic Air Purifier Better overall health. This ionic air purifier is much more than just an effective odour removing air purification system. It silently fills the air with negative ions which research shows can help promote good health and improve vitality. Multi-function Vacuum Cleaner Cat. GH-1196 69.95 $ Create fresh clean air in your home or office with this air purification system with negative ion generator. Ultra modern in design and with silent operation, this is possibly the world's thinnest air purifier, effectively capturing airborne pollutants and allergens to Cat. GH-1198 $ .95 give you a healthy clean environment. Travel Sized Anti-Fog Shaving Mirror with LED Alarm Clock Slim, compact and easy to take travelling. It features an anti-fog mirror so it can be used in the shower where a fold down shower caddy is available to place shaving equipment or toothbrushes. It also comes with an LED Alarm Clock. The Cat. GH-1512 suction cups and clip $ .95 hanger allows for easy installation. 99 39 $59.95 34.95 $ SAVE $5 1.5W High Powered UHF CB Transceiver Massive range! This high-quality light-weight UHF transceiver is ideal for use in many professional and leisure activities. Up to 8k working range Cat. DC-1040 with a hi/lo $ .00 setting to conserve power. 99 Sit back and relax while your robot cleans the house! It automatically moves around obstacles, and an intelligent optical sensor assists in avoiding walls and obstructions. Works best to supplement your manual cleaner, not replace it. Was $199 Cat. GH-1395 179 Eye Massager with Heater Relax and enjoy an eye massage. Combines gentle air pressure and warm compressions to give you the ultimate in stress relief. Using the remote control you can select three functions: Massage - reduce fatigue & stress; Warm compressions - to facilitate circulation to increase Cat. GG-2262 oxygen supply to the eye area and $ .95 Gentle air pressure - to reduce eye strain. CB RADIOS Rechargeable 40 Channel UHF Transceiver SAVE $30 Great range, great features! Since the outstanding success of our popular DC-1010 transceiver, it only seemed logical to refine the design, adding a few enhancements along the way. It is a lot more compact, measuring just 53(W) x 95(H) x 32(D)mm. It uses a small rechargeable battery pack, and is supplied with a dual charging cradle. You can still of course use AAA batteries as a backup. Four step scrambling is also provided for private communications, making this transceiver just plain fantastic! Supplied with one transceiver and a charging Buy an extra cradle. Was $89.95 transceiver (DC-1028) for Cat. DC-1025 just $49.95! $ .95 Save $20! 59 INTERNET> www.jaycar.com.au Shocking Battle Tanks No Guts - No Glory'. These futuristic battle tanks actually pack a punch and you will cop a mild electric shock if your tank gets a direct hit from your opponent. Was $99.95 SAVE $20 Cat. GH-1099 79.95 $ Shocking Shooting Game A shocking test of your aim and nerves. Strap on the chest targets, set the guns to 'Wimp' or 'Tough Guy' shock level then fire away. When hit, you get a shock through the gun's hand grip. Five strikes and you're out. SAVE •Sold per pair $10 •Batteries included Was $79.95 Cat. GH-1098 64.95 $ Electric Shock Roulette $ FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 SAVE $20 99 40 Channel UHF CB Band Transceiver Cat. DC-1010 This is a great unit for focusing on small problem stains, marks, and dirt on all sorts of surfaces. The ultrasonic transducer generates a strong 50kHz sound which produces millions of microscopic bubbles that loosen and remove dirt and grime. They provide a safe and simple means of cleaning many things such as jewellery, Cat. YH-5404 stubborn stains on clothes, walls, $ .95 and carpets, and much more. 99 Negative Ion Generator with Filter Cheap short distance communication! They operate up to 5km in an open field, or 1km in the city. Lots of accessories available, see our website for details. Was $39.95 or 2 for Shocking Low Prices! Ultrasonic Cleaner Play Russian Roulette without the life threatening hazards! The looser gets a mild electric shock. Up to 4 players Was $24.95 SAVE Cat. GH-1092 19.95 $5 $ Shocking Lie Detector Your mates will tremble as you question them about the size of the fish they reckon they caught or how many of your beers they drank.160mm dia Was $44.95 SAVE $10 Cat. GH-1093 34.95 $ Electric Shock Reaction Game The ultimate test in speed, reflex and concentration. •Looser gets a mild electric shock. •Electrifying fun Was $49.95 SAVE $15 Cat. GH-1095 34.95 $ As seen on TV Simple Biodiesel Book Biodiesel Fuel is a diesel fuel you can easily make yourself at home. With simple methods spelt out in this book, you can produce fuel for a modern day diesel engine from vegetable oil (even used 'fish and chip' oil). Takes you through everything from starting your oil collection service to testing and using your fuel on the road. 61 Pages, softcover. Cat. BE-1531 29.95 $ 7 Setting The Mood Fog Machine Magic Eggs Great for parties! It emits a harmless fog that can help create great lighting effects, mystical low lying fog, and more. 240VAC mains powered. Requires Cat. AF-1212 fog juice. Cat. AF-1210 $ .95 99 1L Fog Juice for Fog Machine Cat. AF-1212 $ .95 9 Disco Party Light Set Create your own dance party atmosphere! Get your party started the right way with some creative lighting to help set the mood. Just add music and you’re set! All mains powered. Kit contains: •20cm mirror ball. •1RPM mirror ball motor. •PAR36 spotlight. Cat. SL-2978 •PAR36 globe. $ .95 •4 x coloured gels for PAR36. 69 PAR36 Spotlight with Colour Wheel and Motor 75W Strobe Light Super bright! Strobe lights have been very popular for many years. This unit features a super bright 75W flash tube and can be timed with music or independently. See website for full details. Designed for domestic use only. Cat. GH-1804 $ .95 24 Aromatherapy Table Lamp Soothing and relaxing! Relaxing aromas will fill your room without the danger of candles. Lavender, sandalwood, and lemongrass supplied. Mains powered. Cat. GH-1045 $ .95 Was $39.95 Cat. GH-1806 $ .95 49 Colour Morphing Disk This exciting colour morphing disk features a sound modulation system that creates unique light patterns that change in sync with the sounds or music around it. Requires 4 x AAA batteries (Available separately). It measures approx. 80mm dia. x 30mm thick. 29 SAVE $10 Colour Master Colour Changing LED Lighting Kits 19 89 79 Mini Strobe Light SAVE $5 Great for parties! Features a variable flash rate up to 10Hz, and is mains powered. Uses a Xenon flash tube, and measures 85(W) x 50(H) x 125(D)mm. Cat. SL-2990 $ .95 Was $29.95 3 in 1 Indoor Games Set This flat panel disk produces an amazing display of blue light which responds to your touch, voice or music. Comes with a removable stand & can be wall mounted. Mains power adaptor included. •254mm/10" (dia.) •6” version also available GH-1530 $39.95 The stylish glass chess board features chamfered edges and 'shot glass' chess pieces. The set also includes two decks of playing cards and checkers pieces. Cat. GH-1532 $ .95 49 Portable Plasma Ball A sphere of magical plasma light that you can take anywhere! It creates a dramatic display of multicoloured light under a handblown glass dome. Requires 2 x AA batteries and measures Cat. GH-1527 $ .95 135(Dia) x 145(H)mm. 24 39 or 5 for $10 ALL COLOURS $ .50ea 2 Cat. GT-3005 $ .95 19 Snakes and Ladders Drinking Game Just like regular snakes and ladders, but with an alcoholic twist! Challenge up to 3 people and see who can overcome the shot-traps and snakes to reach the top of the ladder. Includes 1 x dice, 4 x shot glasses and 4 x glass coasters. Was $19.95 Cat. GT-3008 $ .95 9 SAVE $10 Illuminated Scrolling Message Mug Ice Rope Light Ideal for parties, shop fronts or to add to your Christmas cheer. Its 10 metres long and includes a controller to either have the lights on continuously, flashing, chasing or fading. 139 19 10" Plasma Disk Cat. SL-2999 $ .95 8 Three Piece 34 79 44 Great low price! They produce a soft glow for up to eight hours. Great for dance clubs and parties! Size 150(L) x 18(Dia)mm. ST-3160 Red ST-3161 Yellow ST-3162 White ST-3163 Blue ST-3164 Pink Single This great looking lamp $5 changes from hues of red, purple, blue, green and pink. It can be automatically set up to change colours at various speeds or see it morph to the sound of your voice or music! It’s perfect for creating soft ambient lighting in your bedroom, living room, dining area or outdoors. Was $39.95 Cat. GH-1049 $ .95 Fun and funky! Mount them in laminate or Cat. GH-1800 wooden floors, walls, or even ceilings for great $ .95 mood lighting. They can be changed from red, blue, or green, auto changing or static. Supplied with Recessed Colour LED Lights controller and mains plugpack. Lights measure Illuminate in style! 80(Dia) x 6(H)•mm. •6mm protruding from mounting They are great for illuminating paths, Two packs available: driveways, and even floors because they Cat. ST-3880 Four Light Pack $ .95 mount completely flush. Mains powered, Includes 4 x round LED fittings, the lights measure 27(H) x 30(Dia)mm. 12.5m of cable, and controller. Can be expanded to 10 additional lights. Cat. ST-3882 Eight Light Pack ST-3887 4 pcs white pack $ .95 Includes 8 x round LED fitting, Cat. ST-3887 Cat. ST-3885/6 ST-3885 White 22.5m of cable, and controller. $ .95 $ .95 ST-3886 Blue Set the mood! The advanced screw-cap globe holder design is much better than the older spring-clip style which were clumsy. The 245mm five-colour wheel and motor is easily mounted for simple installation. •Globe not included. Cat. SL-2963 Use SL-2964 $9.95 $ .95 Glow Sticks Create an intimate party atmosphere these egg shaped lights. Watch in amazement as they change from one colour to the next. The egg can be lifted from their recharging base and placed anywhere around the house or outdoors. They are lot safer to use than traditional candles with the added benefit of coloured lighting that lasts up to 6 hours when fully charged. No batteries or wires required. Includes charging station and mains adaptor. •Size of egg 95(H) x 65(W) x 70(dia)mm Desktop Mood Lamp with Sound Modulation SAVE 8 interchangeable messages that light up at the base and look spectacular in dark areas. •Holds 500ml •Uses 4 x AA batteries (not inicluded) Was $24.95 Cat. SL-2820 $ .95 39 SAVE $5 Cat. GH-1307 $ .95 19 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Car Parking Timer FM Stereo Transmitter with LCD 12V Can Cooler Cold drinks on long trips! This great device plugs into your car’s cigarette lighter socket and holds a standard size 375mL can. It is a great way to keep your drinks cold in summer, Cat. GH-1370 $ .95 and on long trips. Don't get caught at an expired parking meter. This timer can be set up to 19hours 59minutes in 1 minute increments and features a clock and keychain as well. Weighs only 21g & uses a 1.5V button cell.(Supplied) Cat. XC-0121 $ .95 Full FM selection! Play your iPod/CD/MP3 player through your car stereo. Select any frequency in the FM band. Requires 2 x AAA batteries. Cat. AR-3115 $ .95 29 59 9 Reversing Sensor with Dashboard Display Alcohol Breath Tester with Not only does this LCD Readout excellent reversing sensor alert you to objects or people behind your vehicle, it will also give you and estimated distance to them and indicate their approximate location via the dash-board mounted display. Cat. LR-8869 $ .00 199 Power Window Closers Let your alarm wind up your windows! This unit interfaces with your car alarm to automatically wind up electric power windows when you arm your alarm. It can be used with positive or negative triggered windows, and of course you do need to have power windows Cat. LR-8851 already fitted. Two models available: $ .95 Two Door Version Cat. LR-8851 Cat. LR-8853 Four Door Version Cat. LR-8853 $ .95 49 59 LEARNING REMOTES Key Fob Learning Remote This key fob transmitter will learn the code of a cars’ transmitter. It can learn up to 4 different frequencies. •Supplied with full instructions. •Frequency: 290MHz - 410MHz •Note: This is not suitable for code hopping alarms. not be relied on for precise results, and you should never drink and drive. Cat. LA-8990 $ .95 39 Cat. LA-8992 $ .95 49 The most popular single channel unit! These are probably the most circulated remote control around in service. If you have lost or worn out yours this will save ordering one through the garage door people who charge a fortune for replacements. Cat. LR-8827 Requires 9V battery - $ .95 not included. Motion Sickness Relief Worn like a watch with a skin contact sensor! Just wear this comfortable watch like device on your inner wrist and the adjustable massaging vibrations target specific acupressure points that relieve the motion sickness either before or even after it begins. Cat. GH-1445 $ .95 69 Stop thieves dead in their tracks! It has an ear piercing 120dB siren, and is triggered by a number of events. Supplied with electronic black box controller 90(W) x 32(H) x 75(D)mm, two slimline key fob Cat. LA-9020 remote controls, wiring looms, red .95 flashing LED warning light, and siren. $ 69 Massage Seat Cover Pad with Built in Heater INTERNET> www.jaycar.com.au 49 49 Ideal for camping or for long road trips! This multifunctional smart tray can be mounted on the steering wheel and can assist the driver (without any travelling companions) by attaching to the front passenger seat or on the seat back. It can be used as a Cat. GG-2147 desk providing a convenient place for a $ .95 notebook, food or drink 24 Motorcycle Alarm Designed to be used in the car, home or office, it is light weight to take anywhere with you. •Mains Adapter & Car Cigarette Lighter socket (included) •Size: 109(H) x 53(W)mm Cat. GH-1753 $ .95 Cat. XC-0352 $ .95 Smart Tray 5mm Red 12V LED 150MCD FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 69 1 Gate or Garage Remote 59 Stay safe and under the limit on the roads! This unit is very compact & features an integrated LCD to give you an actual readout of your blood alcohol content. While providing a good Cat. QM-7294 $ .95 indication of BAC, it should The perfect LED for the car! At last a 5mm LED that can be Cat. ZD-1784 used in a car that does not $ .60 need a dropping resistor. Key FOB Learning Remote This key fob transmitter will learn the code of a cars’ transmitter. It can learn up to 4 different frequencies. •Supplied with full instructions. •Frequency: 250MHz - 450MHz •Note: This is not suitable for code hopping alarms. Wireless Key Finder Never lose keys again! Simply attach your keys to one of the receivers. Then when you press the corresponding button, it will beep so you can find it. There are four receivers supplied, each with their own button on the keyfob style transmitter. Digital Tyre Pressure Gauge Stay safe on the roads! Incorrect tyre pressures can have adverse affects on handling and stopping distance. Keep check on your tyre pressures easily. 0 to 150PSI range. Cat. GG-2310 $ .95 19 5 Pc Bicycle Tool Set with Carry Bag Great for emergencies! It contains a hand pump, puncture repair kit, twopiece tyre lever, Allen keys and a stainless steel multi tool, all stored in a nylon pouch. Great for on the road, or general maintenance at home. Car Boot or Hatch Release This great little gadget installs on you boot or hatch lock so that unlocking simply involves pressing a button (supplied)!. •Solenoid unit (inc. bracket): 95(L) x 43(D) x 58(H)mm Cat. TH-2137 $ .95 29 Cat. LR-8834 $ .50 32 9 The Amazing Flygun! Keep your cool! These fans have a water spray to use on those scorching summer days. Small size GH-1070 Large size GH-1072 3 Fishing Tool Set 19 How far is the next turn off? Automatically convert a map’s scale distance to real distance by rolling the small wheel along the desired route. It works with any map scale and displays in kilometres or miles. Cat. XC-0375 $ .95 19 Create a party atmosphere or add charm to an intimate setting with these environmentally friendly lights. Made from water resistant clear plastic, they feature a solar panel and an extra bright Light Emitting Diode (LED). Charge them up in sunlight for at least 12 hours and enjoy up to 24 hours of continuous use. They have a light sensor so they will turn on in the dark. The solar ball looks fantastic hung from the ceiling or trees, you can even float them in the pool or pond. ST-3120 Solar Ball red $24.95 each or ST-3122 Solar Ball blue BUY 3 FOR $60 ST-3124 Solar Ball white Solar Pond Pump 199 Keep your cool in summer! It will create a refreshing breeze to keep you cool. Measures 130(W) x 160(D) x 75(H) folded. 12V Camping Shower Cat. GH-1074 $ .95 Stay safe in emergencies! Breakdowns & flat tyres at night can be dangerous and the more warning you can give other drivers of your presence, the safer you will be. It features a torch, flashing LED light, with a magnetic and tripod type base. 19 8L Collapsible Bucket Cat. ST-3875 $ .95 39 Rock Climbing and Hiking Altimeter Great for hiking or rock climbing trips this summer! The rugged aneroid mechanism allows measurement from sea level to 5000 metres. Includes a small compass, thermometer, lanyard, and belt clip. Was $49.95 Cat. QM-7280 $ .95 SAVE 39 Sea Scooter Cat. YH-5450 $ .95 49 Preset your drinking temperature to room temperature, luke warm, hot and very hot and the mug will keep it there. Holds 450ml and has a retractable lid to prevent spilling. Includes 12V power lead with cigarette lighter plug. Was $39.95 Cat. GH-1302 $ .95 SAVE $10 Buy a collapsible bucket and a camping show for only $29. er 90 SAVE $5 No need for wasted storage space! This bucket collapses down to just 255 x 35mm when not in use. Measures 255 x 230mm Cat. GH-1260 open with an 8 litre $ .95 capacity. 14 Battery Free Torch $10 Digital Compass with Clock and Thermometer $10 A touch of luxury! Wash away the cares of the day - no matter how far from civilisation you are! The camping shower allows you to take a shower wherever you are. Powered by your vehicle’s 12V battery. Cat. YS-2800 $ .95 Stay on the right track! Don’t mess around with mechanical compasses. What if it gets dark? This LCD unit is backlit, so you can get your bearings whenever you want without fumbling with torches. It is supplied with suction cup mounts and a lanyard. Cat. QM-7262 SAVE $ .95 Was $59.95 Travel Mug with Heater 10 Cat. XC-0293 $ .00 Multi-Function Torch Warning Light LED Solar Balls 29 7 9 Digital Map Distance Calculator Add a touch of wonder and grace to your pond with this floating pond pump. Two solar panels turn direct sunlight into electricity to run the submerged pump. Squirts water up to 450mm high in full sunlight. As the sunshine fades in the evening the pump's output slowly diminishes. Includes three sprinkler heads and riser tube. •330(D)x98(H)mm. Replacement Pump YH-5451 $19.95 Cat. GH-1072 $ .95 Personal Desktop Fan SAVE $10 SAVE $50 Wireless sensors! The system monitors inside and outside temp, air pressure, rainfall, humidity, wind speed and direction, and wind chill factor. Check our website for all the features. Was $249 Cat. GH-1070 $ .95 7 A must have for every recreational fisherman! It includes a 14 in 1 multi tool, 0 - 6kg scales, and an LED hand torch, all in a convenient Cat. TD-2053 belt pouch. $ .95 Was $29.95 Wireless Weather Station with Wind Direction & Rain Gauge Personal Fans with Water Spray SAFE FOR AGES 8 Keep the kids entertained! AND UP The Amazing Flygun is a safe, fun, and effective method of killing flies and mosquitoes. Launch the spring powered swatter at your target! It is safe, fun and really does work! Cat. YS-5545 $ .95 49 No batteries needed. Just shake and the mechanism SAVE produces a current $2 to run the torch's LED. If the torch dims, shake it again. This compact torch will fit easily into you glovebox or around the house for those times you need a light in a few "shakes". 165mm in length, waterproof, weatherproof and it floats in water! Cat. ST-3340 Was $14.95 $ .95 ST-3344 12” version also NEW available for $24.95 12 5W Luxeon LED Hand Torch Blinding white light! If you need a super bright torch, this one’s for you. It houses a super bright 5W Luxeon LED which is the brightest on offer at 120 Lumens. Requires Cat. ST-3338 SAVE 6 x AA batteries. $ .95 $20 Was $149.95 129 Check this out!!! Here's a great water scooter that's been designed specifically for family fun in the pool, lake or protected beaches. The powerful motor can reach a maximum speed of 3km/h and is powered by a rechargeable battery which gives around 40 - 60 mins running time. It's lightweight enough to carry with one hand and portability is guaranteed by the included sports carry bag - perfect for the kids to take on your next riverside picnic. It's easy to manoeuver and control with comfortable grip handlebars and can even be used for shallow snorkelling. •Powered by 12V 7AH battery (included) Cat. GG-2350 •Up to 1 hour's intermittent use time or $ .00 40 min continuous •Thrust: 5kgf 249 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au CAR AMPLIFIER DEAL Celebrate our hot new car audio range! Buy any of our amps together with any of our top quality splits and receive a massive 25%* off full retail price on power and speaker cable purchased at the same time! *Does not apply to already discounted cable Check out our massive amplifier range Touch Screen TFT In-Dash 7" Widescreen TFT LCD Monitor Bursting with value. This 7" 12V monitor has superb picture resolution & exceptional audio clarity. Featuring touch screen capabilities, which enables use with laptops/PCs or other VGA operated peripherals with USB interface. For those who want to complete their in car entertainment system with a top of the line viewing device. Retracts away from view! Mounting into a single DIN space, it can be stored in its housing to avoid attracting thieves, or left out on display. Accepts standard video signals, powered by 12VDC, and Cat. QM-3749 $ .00 includes a remote control. 549 LCD Headrest Bracket 14 Amplifiers TFT & LCD Screen Cleaning Kit 2x80WRMS Remove dust and fingerprints without streaking, scratching or staining.Kit includes: •Elastic anti-static Brush •Drip-free cleaning solution 4x100WRMS •The special micro-fibre 4x50WRMS •4 x 130WRMS <at> 4 ohms cleaning material is capable 4 x 50WRMS <at> 4ohms 4 x 80 WRMS <at> 2ohms •4 x 190WRMS <at> 2 ohms of preventing panel scratch 2 x 160WRMS <at> 4 ohms •2 x 380WRMS <at> 4 ohms and will not harm the LCD's protective coating Cat. AA-0426 $299.95 Cat. AA-0422 $199.95 2 x 80WRMS <at> 4 ohms 2 x 100WRMS <at>2 ohms 1 x 200WRMS <at> 4 ohms Cat. AA-0420 $169.95 2 x 150WRMS 800WRMS Class D 2 x 150WRMS <at> 4 ohms 2 x 255WRMS <at>2 ohms 1 x 500WRMS <at>4 ohms Cat. AA-0424 $249.95 1 x 400WRMS <at> 4 ohms 1 x 700WRMS <at> 2 ohms 1 x 820WRMS <at> 1 ohm Cat. AA-0428 $399 Carbon Fibre Subwoofers New range! Featuring high quality Carbon Fibre cones and dual voice coils, these new subwoofers offer great performance and durability. •See website for full details. 10" Subwoofer •300WRMS power handling. •Dual 4-ohm voice coils. CS-2279 $ •88.2dB sensitivity. 219.00 Kevlar Cone Coaxial Speakers Fantastic quality! This new range of coaxial speakers offer high performance and great looks. They retain the large super tweeter that made last year’s range great, but the new Kevlar cones take them into a realm of their own. Check out our catalogue on page 229 or our website for full details. Cat. •40WRMS power. CS-2320 $ .95 99 •86.5dB sensitivity. Cat. 5" Kevlar 2 Way •50WRMS power. $CS-2322 .95 •89.5dB sensitivity. 109 Cat. 6.5" Kevlar 2 Way •75WRMS power. CS-2324 $ .95 •91.3dB sensitivity. 119 Cat. 6" x 9" 2 Way •80WRMS power. CS-2328 $ .95 •93.5dB sensitivity. 139 14 Includes plug for Dell laptops! Power your laptop on the go from a 11 - 16VDC source. It can provide 15, 16, 18, 19, 20VDC <at> 6A, or 22, 24VDC <at> 5A. Lightweight switchmode Cat. MP-3466 $ .00 design, 6 plugs included. Cat. QP-5550 $ .95 49 Great value! With a host of safety features such as overload & short circuit protection, dielectric isolation between the battery and secondary voltages and more. They all have excellent surge ratings and boast over 90% efficiency. Cat. SZ-2074 $ .95 Simple tester for a simple problem. Don’t get caught with a faulty spark plug. Bright neon illumination indicates spark presence. Cat. QP-2264 $ .95 5 1 Farad 20V Capacitor with Voltage Display Car audio enthusiasts please note! This massive capacitor will help stabilise the voltage levels in a high power stereo installation. A voltage display keeps you informed of voltage levels, and mounting hardware is included. Cat. RU-6750 $ .95 99 INTERNET> www.jaycar.com.au SAVE $50 119 Neon Spark Plug Tester FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 249 Modified Square Wave Inverters The easiest way to find a blown fuse! When it blows, an LED lights up! It has provisions for 2 gauge or 4 gauge cable inputs, and 4 x 4 gauge outputs. Accepts 5AG fuses. 12" Subwoofer 4" Kevlar 2 Way Cat. AR-1418 $ .95 4 Way Distribution Block with Blown Fuse Indication •250WRMS power handling. •Dual 4-ohm voice coils. CS-2278 •87.1dB sensitivity. $ 179.95 Cat. QM-3752 $ .00 Automotive Laptop Power Supply Digital Voltage and Current Terminal Block Keep an eye on power conditions! It features two 3 digit 7 segment LED displays to display voltage and current, and 4 gauge input and output terminals. It can measure current up to 200 amps! 369 7" TFT LCD Widescreen Colour Monitor Delivers high resolution pictures in widescreen format and clear sound reproduction through its inbuilt speaker. A truly versatile monitor with low power consumption, wide viewing angle and NTSC and PAL compatiblity. Includes remote control. Was $299 Headrest Bracket to Suit Great versatile mounting option. Cat. QM-3757 $ .95 Cat. QM-3753 $ .00 44 Power Surge VDC VAC Cat. No. 100W (300W) 12 to 230 MI-5100 Suits battery chargers, lights, & low power devices WAS $44.95 SAVE $5 NOW $39.95 150W (450W) 12 to 230 MI-5102 $48.95 Suits battery chargers, fax machines etc! 300W (1000W) 12 to 230 MI-5104 $99.95 Suits laptops, lamps & fluorescents up to 300W, 34cm TVs etc WAS $119.95 SAVE $20 400W (1200W) 12 to 230 MI-5106 Suits laptops, lamps & fluorescents up to 400W, 54cm TVs etc ONLY $159.95 400W (1200W) 24 to 230 MI-5107 Suits laptops, lamps & fluores to 400W, 54cm TVs & more from 24V ONLY $169.95 600W (1500W) 12 to 230 MI-5108 Suits power tools, 68cm TVs, laptops, microwaves, small fridges etc ONLY $249.95 800W (2000W) 12 to 230 MI-5110 Suits power tools, 68cm TVs, blenders, small fridges, microwaves etc ONLY $299.95 1000W(2500W) 12 to 230 MI-5112 Suits Hi-Fi systems, computers, 68cm TVs, lighting, fridges etc ONLY $399.95 1500W(3500W) 12 to 230 MI-5114 Suits large TVs, many power tools, lighting, computers etc ONLY $599.95 11 WIRELESS SECURITY 2.4GHz Weather Resistant Wireless Colour CCD Camera with IR LEDs Night vision! As well as 420TV line resolution, this camera has 27 integrated infrared LEDs to see in the dark. It is weatherproof, great for mounting under eaves, and a mains plugpack is included. QC-3588 receiver required. Two channels available: Both Types Channel 3 Cat. QC-3564 $ .00ea Channel 4 Cat. QC-3565 269 2.4GHz Wireless Colour CCD Rechargeable Camera with Audio The ultimate in portability! This camera features an internal Lithium-Ion rechargeable battery that can operate the camera for up to 5hrs per charge. Channel selectable to use with QC-3588 receiver, see website Cat. QC-3595 $ .95 for details. 8 Port DVR Card Specifically for professional security use. This card takes 8 video inputs and 1 audio inputt. Being 2 cards rather than a single card, this allows the DVR system to record at a global frame rate of 50 Cat. QV-3059 frames per second rather than 25 $ .00 frames per second like other models. RFID Access Control System 399 No contact required! Control entry to a doorway, or an entire building. The unit can be used in a network of locks administered by a central location, or just to control access through a front door. It is 12V powered, so you can use it in remote locations, and the reader unit is splash proof. •5 RFID cards included. Cat. LA-5120 $ .00 •N.O. and N.C. relay contacts. 199 169 2.4GHz 4 Channel Wireless USB Receiver Wireless Intercom with Door Strike Release Open the door from anywhere! This great unit acts as an intercom, Surveillance on your computer! with a wireless receiver. Take it out This tiny four channel receiver takes the pain out of the back, or around the house. It AI-5510 surveillance.Just plug it into your PC’s USB port also has electronic door strike control, Cat. $ .00 and you’re set. You can view cameras on the so you can let your visitors in too! PC, with a composite option for a TV or monitor Long Range 120m Twin too. There is a host of on-board functions Beam Driveway Monitor such as email alert 240m range indoors! on motion detection, Now you can reliably monitor an entry and a whole lot more. See page way of up to 240m indoors, or 120m 313 of our 2005 catalogue for more info. Cat. QC-3597 outdoors. Installation is easy thanks $ .95 to built-in laser guides, and dual beams Cat. LA-5199 2.4GHz 4 Channel Wireless $ .00 help eliminate false alarms from birds or debris etc. See website for details. Receiver with Remote Control Audio and video! Receiving up to four 2.4GHz cameras (any of the cameras CCD Colour Dome Camera shown), you can switch with Pan / Tilt / Function between cameras manually, Versatile monitoring! This camera or set it to automatic. is integrated into a weatherproof dome Composite video output housing, suitable for ceiling mounting. allows display or Just use the remote control to follow recording on any device. Mains Cat. QC-3593 the action! It uses a 1/3" Panasonic plug pack & cables are also supplied. $ .95 colour CCD sensor to provide quality 420TV line resolution Cat. QC-3497 2 Input Video IP Network Web Server video. $ .00 Compatible with most CCTV products. Upgrade your CCTV to an IP (Internet Protocol) surveillance system.The unit can be given a Pan / Tilt / Zoom Control Receivers Very versatile! fixed or router They interface with the assigned IP address controller above to which allows camera images to be viewed and controlled from anywhere in the world via an internet control Pan / Tilt / Zoom cameras, as well as browser. The setup interface is very user friendly. See webite or our catalogue for Cat. QC-3394 focus and iris controls $ .00 when required. They can full specifications. be used up to 2km away from the controller, and also have a relay IP Addressable Camera Cat. QC-3212 output for controlling lighting or locks $ .95 Remote surveillance? etc. See website for details. No worries! 129 249 299 DOOR PHONES B&W Video Doorphone See who’s at your door before you let them in! The 4" screen lets you see your visitors, and you can talk to them through the handset. Supplied with all mounting hardware and wiring. SAVE Was $199 $20 Cat. QC-3602 $ .00 179 Colour Video Doorphone Top quality! The colour camera, and LCD screen give you excellent clarity to the picture. Supplied with all mounting hardware and wiring. Was $399 Expand the system! Buy an extra colour receiver QC-3607 with your video doorphone for just $199. Save $150! Cat. QC-3606 $ .00 359 SAVE $40 Video Doorphone with Colour LCD Monitor Features a 5.6" colour TFT-LCD screen. The external unit consists of a colour CMOS camera, speaker, microphone and call-button housed in a strong plastic case. Other features include a Warning button that sounds an alarm through the outside panel and a Monitor feature so you can seen what's happening at the door whenever you wish. Accessories include a 15m interconnecting cable, volume and contrast controls plus a plug pack Cat. QC-3612 $ power supply. 499 PA N / T I LT / Z O O M C A M E R A S 129 499 Pan / Tilt / Zoom Dome Camera Fantastic price! Don’t pay thousands, this unit has 420TV line resolution, 350° panning angle, and 90° tilt range. It has 3x optical zoom with 4.2 – 12.7mm focal length. It has many features normally reserved for high priced units. Cat. QC-3500 $ .00 799 NEW PAN / TILT / ZOOM CAMERA CONTROLLERS 399 This internet addressable camera features an integrated web server, so there is no need for a computer! Also has a local composite video output. Was $249 12 149 SAVE $60 IP-65 Weatherproof Receiver Cat. QC-3390 $ .00 189 Cat. QC-3214 $ .95 189 Pan / Tilt / Zoom Controller Expandable performance! When this unit is combined with the control receivers shown below. You can control up to 100 receivers, so it can provide the base to a very sophisticated and elaborate surveillance setup. It also has support for control of focus and iris controls, and Cat. QC-3213 uses PELCO D control protocols for $ .95 reliability. See website for details. 249 Video / Power / Data Cable for Pan / Tilt / Zoom Cameras Long distance communication! Send your video, power, and data over Cat5 UTP cable Cat. QC-3431 up to 300m (colour) $ .95 or 600m (B&W). 39 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Buy in Bulk and Save 40 Pack AA Eclipse Batteries We have a massive range of rechargeable high capacity batteries and chargers! Check out these NiMH AA/AAA individual and bulk prices. Buy in bulk and SAVE! These are high quality alkaline batteries, at almost half the price of small pack equivalents. THAT’S UNDER Cat. SB-2332 50c EACH! $ .95 Cat. # Terminal Type SB-1723 nipple AAA SB-1724 solder tag AAA SB-1700 nipple AA SB-1706 nipple AA SB-1708 solder tag AA SB-1727 nipple AA PACKETS OF FOUR SB-1739 nipple AAA SB-1737 nipple AA SB-1735 nipple AA Capacity 900mAh 900mAh 1650mAh 2000mAh 2000mAh 2400mAh Qty 1+ BUY 10 FOR $2.79 ea $2.45 ea $3.78 ea $3.30 ea $2.95 ea $2.60 ea $3.95 ea $3.45 ea $5.75 ea $4.95 ea $5.95 ea $5.25 ea 900mAh $11.95 ea 2000mAh $15.95 ea 2400mAh $19.95 ea $10.70 ea $14.35 ea $17.70 ea SAVE $0.34 ea $0.48 ea $0.35 ea $0.50 ea $0.80 ea $0.70 ea SAVE $$$ 19 NiCd/NiMH Battery Charger 4 x AA/AAA/C/D/9V with LCD $1.25 ea $1.60 ea $2.25 ea Similar to the MB3542 however will charge 4 x C, D and 9V batteries as well. 1 Hour Super Fast Battery Charger Ni-Cd/Ni-MH w/car Adapter Bulk Pack Alkaline Batteries These bulk packs of alkaline batteries represent excellent value for money. We have them made to the same specifications of those well known expensive brands advertised on TV, but at a realistic price.With a shelf life past the year 2010 you cannot go wrong! AAA Cat. SB-2331 Bulk Pk of 24 $12.95 AA Cat. SB-2330 Bulk Pk of 24 $12.95 20A Solar Charging Controller with LCD Protect your batteries! This microprocessor controlled unit is capable of handling all of your solar charging requirements. It has an array of features including adjustable charging voltage, auto dusk-till-dawn on/off, overload protection & a whole lot more. See our website for full details. Cat. MP-3129 $ .95 Never find yourself with flat batteries again. This battery charger recharges 1 to 4 pieces of AA or AAA batteries in one hour. Along with the AC adaptor is a 12V cigarette car adaptor. Voltage input of 100-240VAC. Was $69.95 Cat. MB-3544 $ .95 59 4 x AA/AAA NiCd/NiMH Battery Charger with LCD Display Recharge four of either AA or AAA Ni-Cd, Ni-MH, or rechargeable Alkaline batteries. The charger has an LCD display that shows battery charge state and is supplied with mains plug-pack SAVE $10 Cat. MB-3537 $ .95 59 Switchmode Dual Stage Lead-Acid Battery Chargers Cat. MB-3542 $ .95 49 Wind Powered Generator Experimenters Kit 169 Battery Fighter Chargers ® Fully charge and maintain a lead acid battery at the correct storage voltage. Ideal for vintage cars, boats or planes that sit for months at a time without use. Lack of use causes a lead-acid battery to self discharge and may result in a destroyed cell. A replacement battery will cost more than these chargers. Cat. MB-3600 $ .95 12V 750mA Battery Fighter® Charger 49 Cat. MB-3602 $ .95 12V 1.2A Battery Fighter® Charger 79 HIGH CURRENT POWER CONNECTORS You'll find this connector in many 4WD applications, boating, automotive and other industries. Supplied individually with a pair of contacts and rated to 600V. Cat. PT-4420/22/24 Cat. PT-4405 Current 30 Amp 50 Amp 120 Amp 175 Amp Poles 2 2 2 2 Cat PT-4405 PT-4420 PT-4422 PT-4424 Price $5.95 $12.95 $28.95 $37.95 Suits sealed or unsealed Lead-Acid batteries! These fully automatic chargers use switchmode technology to efficiently charge high capacity batteries. They are housed in a robust metal frame, can be powered from 110 or 240V, feature fan cooling, and include 700mm fly leads with heavy duty battery clips. The two larger models also feature an LED bargraph to indicate charging status. See website for full details & specs. 12V <at> 6A Cat. MB-3610 $ .95 79 99 24V <at> 6A Cat. MB-3614 $ .95 99 SOL AR PAN E LS Very affordable! These are Amorphous Silicon type solar panels offering excellent quality, and value for money. Be aware of cheap Amorphous solar panels which will simply not give the claimed output power. All our panels will give claimed power at 33.5°S latitude, ie, Sydney. Amorphous power output gradually decreases over the years, unlike polycrystalline which do not. Voltage 6 Volt 12 Volt 12 Volt 12 Volt 12 Volt Power 1 Watt 2 Watt 4 Watt 10 Watt 15 Watt INTERNET> www.jaycar.com.au Cat No. ZM-9020 ZM-9024 ZM-9026 ZM-9030 ZM-9045 Cat. KJ-6696 $ .95 49 BP Solar 12V Polycrystalline Solar Panels Amorphous Type Solar Panels FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 12V <at> 12A Cat. MB-3612 $ .95 A great learning tool! This small scale project enables you to build a real working wind generator, and then use it for experimenting. It can supply up to 10VDC <at> 1A (depending on wind speed), and features an onboard 330uF capacitor so you can store the energy for later use. Kit includes all parts to make the generator, fan assembly, and pedestal. Stands 250mm high. Price $29.95 $39.95 $69.95 $139.00 $199.00 Top quality panels at a great price! Each panel has an array of 36 Polycrystalline cells, and can charge 12V batteries in virtually any climate. They are built to last, and designed to withstand a 25mm hail stone travelling at terminal velocity. They are mounted in an anodised aluminium frame that is weather proof and corrosion resistant. See website for full details. Power 10W 20W 80W Warranty 10 Year 10 Year 20 Year Cat ZM-9060 ZM-9062 ZM-9069 Price $235 $359 $799 13 VELLEMAN Pic Programmer / Checker Versatile! Supporting 8p, 14p, 18p, and 24p PIC microcontrollers, this board is quite versatile. It includes test buttons and LED indicators for on-board experimenting and testing, as well as programming software. Includes a PIC16F627. Cat. XC-4402 $ .00 119 HKZ-101 Hall Effect vane Jaycar has it back! Previously obsolete, the HKZ-101 has been commonly requested, but difficult to find since Siemens deleted it in 1998. This copy is almost identical, and works very well. See our website for data. True RMS Auto Ranging RS-232 DMM This is one of those really useful gizmos. It consists of a suction cup base and small platform with a series of arms and swivels that can be joined together in a variety of ways to hold things. Mounting height ranges from 80mm to 368mm. Suction base diameter is 70mm. Cat. HS-9000 $ .95 19 4 Channel USB Datalogger Cat. ZD-1900 $ .95 19 Attn: All You “Tim The Toolmen” (The Wealthy Ones Anyway) We now stock the US-Designed Grabit damaged screw removal tool, but BOY it’s expensive!! What it does. If you have a typically, (but not necessarily) countersunk screw that is slotted, Phillips, Posidrive, Torx, Tri-Wing, tamper resistant, etc that is totally stripped out, this product will get it out - even if the head is totally hollow! All of us “Tims” have experienced this! The extraction bit consists of a burnishing bit that basically preps a tapered hole in the screw head. You turn the bit around with the extractor bit out, reverse the cordless drill direction and the extractor bit bites into the prepped hole with tremendous force. Works equally well on brass, steel, stainless screws etc. The TD-2059 consists of two 1/4” hex drive bits that cover screws from #6 to #14 gauge. In days when a 12V cordless drill can retail for $25 this Cat. TD-2059 $ .95 product may seem expensive. What it can do for you is priceless. 49 No more serial! Record DC and slowmoving signals over very long periods. It connects to a PC via the USB port to display real time information, as well as record it. No additional power is required. There are four DC-coupled input channels, monitored at up to 100 samples/second (globally). Cat. QD-5000 $ .95 It has a host of great features, just check out our website. 139 IDEAL Non - Contact 60 to 400VAC Tester You’ll love this laser level with tape measure. Use this tool to hang pictures, paintings or mirrors in your home, install shelving, lay tiles etc. The range of the laser line projects up to 6m indoor and covers an arc of 45 and 90 degrees. The unit incorporates a horizontally spread laser to create illuminated guide lines along walls, Cat. ST-3113 horizontal and vertical levels. It also $ .95 includes a handy 2.5m tape measure as well as a ruler on the side. 39 Handy Laser Level Looks like an ordinary spirit level, except that it has a laser fitted in one end. The laser projects a straight line that covers about 15° of arc and can be viewed over many metres, thus enabling a very accurate level to be maintained over quite a distance. Fitted with SAVE magnets in the base so it can be 'stuck' $5 to steel frames and comes with its own small tripod. Dual bubbles ensure that levels can be maintained in both vertical and horizontal planes. Measures 170(L)x45(H)x20(W)mm. Cat. ST-3114 Was $29.95 $ .95 24 Features a groovy red backlit screen, and a host of features. Includes optical RS-232 computer interface and PC software to store measurements on your home, workshop, or notebook computer for later analysis. Please see our website or catalogue Cat. QM-1537 $ .95 for full specifications. 99 Cat III Auto Ranging DMM Double moulded housing! It features large digits, Cat III 600V certification, and is designed for the professional and serious enthusiast. •Capacitance. •Frequency. Cat. QM-1539 •Relative $ .95 measurement. 69 Double Insulated Probe Style DMM Great for every tradesman’s pocket! Gives an audible and visual indication on energised circuits. It has an unlimited lifetime warranty, and is rated at CAT III 600V. Cat. QP-2274 $ .95 29 Lead Free Solder Works just as well as ordinary solder but contains no harmful lead. Supplied on a 45gm roll with handy cover and available in two sizes. NS-3082 0.9mm dia. Cat. NS-3084 $ .95 NS-3084 1.0mm dia. 15 Laser Level with Tape Measure 14 Gizmo Stand Cat. NS-3082 $ .95 15 10mW Green Laser Module Extremely bright! This laser module consists of a 10mW laser diode, lens, and driver PCB. Simply connect a 3VDC supply, & you have a great Cat. ST-3117 high power laser. $ .95 •Datasheet included. •Measures 65(L) x 11(dia)mm. 149 This probe style multimeter allows you to take measurements without having to look away from where your probes are placed. It makes taking readings from DIL package ICs a whole lot easier by reducing the possibility of shorting out pins with the test probe. The data hold switch is conveniently placed for quick activation. Each range is manually selected, with a range table printed on the front of the probe for easy Cat. QM-1497 reckoning. The probe is double $ .95 insulated for added safety. 19 Digital Optical Tachometer Non-contact! It measures up to 99,999RPM, and can be used to measure RPM or simply count revolutions. It has a large LCD display, laser pointer, and min/max recall. Great for the mechanics workshop or handyperson. Cat. QM-1448 $ .95 69 Precision Mini Metal Lathe Deal Industrial quality on a budget! This fantastic unit has a FULL cast iron bed, frame, and head stock assembly, just like industrial lathes. It bristles with safety features including a plastic chuck cover which must be down for the machine to operate. This prevents you from starting the lathe with the chuck-key in! We have not seen a product of this quality, at this price. See website for details. The cutting tools, drill chuck, and live centre are all usually sold extra, costing over $100, but are included in the price! Was $899 $107.80 worth of parts already included! SAVE $100 Cat. TL-4000 $ .00 799 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Consisting of a 90mm diameter lens and a 12 Watt circular globe enclosed behind a clear protective housing mounted on a 300mm flexible gooseneck. Lens magnification is 3 dioptre. (Replacement fluoro tube QM3521 $9.95). SAVE Was $69.95 $20 Simple and accurate! Useful for checking pH levels in water, fish tanks, swimming pools, and more! It is great in a chemical lab for testing and checking solutions, and the large LCD is easy to read. It has a range of 1 - 14pH, 0.1pH resolution, and +/0.2pH accuracy. 49 This is a high quality, all metal frame construction magnifier which features a 22 watt circular fluoro built inside the magnifier head. The magnifier itself is a 3 dioptre lens. Total extended length 990mm. Cat. QM-3525 (Replacement fluoro tube $ .00 QM-3523 $13.95) 109 S TA R M O D U LE S & A C C E S S O R I E S 79 RFID - Secure Access Without Keys! Radio Frequency Identity (RFID) is a contact free method of controlling an event such as a door strike or alarm etc. An ‘RFID Tag’ transmits a unique code when energised by the receiver’s magnetic field. As long as a pre-programmed tag is recognised by the receiver, access is granted. RFID Security Module Receiver Kit Ref: Silicon Chip June 2004. Provides normally open, normally closed electrically switched outputs. Supplied PCB will mount behind standard wall plate. Kit supplied with PCB, tag, and all electronic Includes components. 1 Keyfob RFID tag worth $9.95 Cat. KC-5393 absolutely FREE! $ .95 See below for extra tags. 89 These tags transmit a 40 bit unique code and are EM-4001 compliant. Two styles available: Cat. QM-3520 $ .95 Super Bright 1 Watt LED Star Modules Cat. QM-1670 $ .95 RFID Tags Desk Clamp Magnifier Light Mini Laboratory Magnifier Lamp Digital PH Meter with LCD Credit Card Style Keyfob Style Cat. ZZ-8950 $ .95 Cat. ZZ-8952 $ .95 9 5 These LEDs are just as bright as the leading brand but cost a whole lot less. They are increasingly finding their way into general and architectural lighting applications and with a service life of 100,000 hours. They provide up to 25 lumens per watt and are available in a number of colours. 1 Watt LEDs Super Bright Star Module - Red Cat. ZD-0500 Super Bright Star Module - Amber Cat. ZD-0502 Super Bright Star Module - Green Cat. ZD-0504 Super Bright Star Module - Blue Cat. ZD-0506 Super Bright Star Module - White Cat. ZD-0508 Super Bright Star Module - Warm White Cat. ZD-0510 1 WATT LEDS $ .95 12 3 Watt LEDs Super Bright Star Module - Red Cat. ZD-0520 Super Bright Star Module - Amber Cat. ZD-0522 Super Bright Star Module - Green Cat. ZD-0524 Super Bright Star Module - Blue Cat. ZD-0526 Super Bright Star Module - White Cat. ZD-0528 Super Bright Star Module - Warm White Cat. ZD-0530 3 WATT LEDS $ .95 23 A collimator is an optical device which is designed to produce a light beam in which the the rays are parallel, or at least very near parallel. While we normally consider LEDs to be very focused in terms of light spread, in many applications there is still a vast quantity of "wasted" light spread.This series of collimators are designed to suit our Star LED modules (lambertian LED models only) and are manufactured from quality optical components. 3 different viewing angles are available: Cat. HP-1290 Collimator - 10° $ .95 10° Viewing Angle 5 Collimator - 15° Cat. HP-1292 $ .95 Collimator - 25° Cat. HP-1294 $ .95 15° Viewing Angle 25° Viewing Angle 5 5 Pre Built Luxeon LED Power Module An affordable power supply for Luxeon LEDs! This pre-built module can power 1, 2, or 3 1W Luxeon LEDs from a DC supply of between 11 and 30V. Cat. AA-0580 $ .95 39 Luxeon Star LED Driver Kit Refer: Silicon Chip May 2004. Luxeon high power LEDs are some of the brightest LEDs Cat. KC-5389 available in the world. $ .95 They offer up to 120 lumens per unit, and will last up to 100,000 hours! This kit allows you to power the fantastic 1W, 3W, and 5W Luxeon Star LEDs from 12VDC. This means that you can take advantage of what these fantastic LEDs have to offer, and use them in your car, boat, or caravan. Luxeon LED Lenses Wide and narrow beams! These lenses are used to evenly distribute light in the desired way. Wide beam lens Cat. ZD-0420 Narrow beam lens Cat. ZD-0422 Cat. ZD-0422 Cat. ZD-0420 $ .95 $ .95 9 Collimators 29 9 T H E S H O R T C I R C U I T S LE A R N I N G S Y S T E M Short Circuits is a great way to learn electronics. It is fun, informative, & you build great projects along the way. Here are some examples of the projects featured in Short Circuits 3 FM Microphone Endless uses! This transmitter could be used as a baby room monitor, a wireless microphone or as a spy bug. It can be picked up on any FM radio, Kit includes PCB, Cat. KJ-8078 electret microphone and electronic $ .95 components. 9 Simple FM Bug Kit Move over 007! This little FM bug transmits to an everyday 88MHz - 108MHz FM radio, and works surprisingly well. You can also use it as a low-cost baby monitor and more. Kit includes PCB, and all electronic Cat. KJ-8230 components. Instructions are in the $ .95 Short Circuits 2 book. 12 Simple FM Alarm Kit Sound Activated Switch Kit Recover your stolen goods! Installed in an appliance, it transmits a tone over the FM band so you can track down goods using an FM radio. Includes PCB and components. Many applications! This project simply closes a relay when a loud-enough sound is heard. It switches off again when the sound stops. Cat. KJ-8084 Kit includes PCB, relay, electret $ .95 mic, and all electronic components. Instructions are in the Short Circuits 3 book. Cat. KJ-8054 $ .95 12 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au 12 LED Audio Level Display Kit Make your music visual! Connect it to the output of your CD, tape, or MP3 player to see the lights dance up and down. Just like on DJ mixing desks! Kit supplied with PCB and all electronic Cat. KJ-8212 $ .95 components. Instructions are in the Short Circuits 2 book. 12 FM Radio Kit with Electronic Tuning Includes a powerful amplifier! This is a true state-of-theart 88-108MHz FM radio with electronic station tuning. It has a voltage regulated power supply and works really well! Includes PCB & electronic components. Cat. KJ-8238 $ .95 Instructions are in the Short Circuits 2 book. 29 15 Digital Fuel Mixture Display Kit Monitor your car’s air:fuel ratio in real time. Ref: Silicon Chip Sept/Oct 2000. This brilliant dash mounting unit features a three digit LED display, as well as a bargraph for readings at a glance. It indicates air:fuel in real time of 11.8 - 20.6 for petrol, and 12.7-21.5 for propane/ LPG. It has loads of great features, just check out our website. Kit includes PCBs, laser cut panels, Cat. KC-5300 pre programmed PIC, and all $ .95 electronic components. 62 Lead Acid Battery Zapper Kit "Clock Watchers" LED Clock Kits EXCLUSIVE TO JAYCAR These clocks are hypnotic! Ref: SC June 2005. They consist of an AVR driven clock circuit, that also produces a dazzling display with the 60 LEDs around the perimeter. It looks amazing, but can't be properly explained here. We have filmed it in action so you can see for yourself on our website! Kit supplied with double sided silkcreened plated through hole PCB and all board components as well as the special clock housing! Available in Red (KC-5404) and Blue (KC-5416) Cat. KC-5416 $ .00 VELLEMAN USB Controlled Interface Kit No parallel, no problems! This interface kit offers Extend the working life of 5 digital and 2 your lead analogue inputs, as acid battery! well as 8 Ref: SC July ‘05 digital and 2 This simple circuit is analogue designed to produce bursts outputs! That is of high-energy pulses to help reverse plenty for the damaging effects of sulphation in "wet" experimenting and lead acid batteries. This is particularly useful when a battery has been sitting for a length of time without use. interfacing with your home or devices in many ways. It is Its effects are dependent on the battery’s condition and powered straight from the USB port, and even has on-board test functions. The kit is supplied with all components, silk type, but the results can be quite impressive. Kit supplied with case, silk screened lid, leads, Cat. KC-5414 screened PCB, assembly manual, and Cat. KV-3600 software. You will not be disappointed. $ .95 $ .95 inductor and all electronic components. YOUR LOCAL JAYCAR STORE Freecall Orders: Ph 1800 022 888 NEW SOUTH WALES Albury Ph (02) 6021 6788 Alexandria Ph (02) 9699 4699 Bankstown Ph (02) 9709 2822 Blacktown Ph (02) 9678 9669 Bondi Junction Ph (02) 9369 3899 Brookvale Ph (02) 9905 4130 Campbelltown Ph (02) 4620 7155 Erina Ph (02) 4365 3433 Hornsby Ph (02) 9476 6221 Newcastle Ph (02) 4965 3799 Parramatta Ph (02) 9683 3377 Penrith Ph (02) 4721 8337 Silverwater Ph (02) 9741 8557 St. Leonards Ph (02) 9439 4799 Sydney City Ph (02) 9267 1614 Taren Point Ph (02) 9531 7033 Wollongong Ph (02) 4226 7089 VICTORIA Coburg Ph (03) 9384 1811 Frankston Ph (03) 9781 4100 Geelong Ph (03) 5221 5800 Melbourne Ph (03) 9663 2030 Ringwood Ph (03) 9870 9053 Springvale Ph (03) 9547 1022 Sunshine Ph (03) 9310 8066 QUEENSLAND Aspley Ph (07) 3863 0099 Brisbane - Woolloongabba Ph (07) 3393 0777 Gold Coast - Mermaid Beach Ph (07) 5526 6722 Townsville Ph (07) 4772 5022 Underwood Ph (07) 3841 4888 AUSTRALIAN CAPITAL TERRITORY Canberra Ph (02) 6239 1801 TASMANIA Hobart Ph (03) 6272 9955 SOUTH AUSTRALIA Adelaide Ph (08) 8231 7355 Clovelly Park Ph (08) 8276 6901 WESTERN AUSTRALIA Perth Ph (08) 9328 8252 NORTHERN TERRITORY Darwin Ph (08) 8948 4043 NEW ZEALAND Hamilton Ph (07) 846 0177 Newmarket - Auckland Ph (09) 377 6421 Glenfield - Auckland Ph (09) 444 4628 Wellington Ph (04) 801 9005 Christchurch Ph (03) 379 1662 Freecall Orders Ph 0800 452 9227 16 39 Cat. KC-5404 $ .95 129 189 50MHz Frequency Meter Kit 69 Cheap and accurate! Ref: SC Oct 2003. It is auto ranging, and displays on a 16 character LCD. Resolution varies between 0.1 and 10Hz depending on the input frequency. Includes all components and hardware. Cat. KC-5369 Requires probe. $ .95 69 Where Have All The Scoreboards Gone? Performance Electronics for Cars Book Over 160 pages! The Performance Electronics for Cars Book from Silicon Chip publications has chapters on modification and theory, as well as the 16 projects. Cat. BS-5080 Basketball Scoreboard Kit 19.80 $ Independent Electronic Boost Controller Change between 2 completely different boost maps at the flick of a switch. Boost curve selection is via a dashboard switch & it is all programmed using the Handheld Digital Controller - KC-5386. Kit supplied with PCB, machined case, and all electronic components. Suitable for EFI and engine management systems only Cat. KC-5387 $ .95 179 Nitrous Fuel Mixture / Motor Speed Controller When activated, it will fire the injector at a preset duty cycle, adding a fixed amount of nitrous fuel. It also makes a great motor controller, to control an electronic water pump, additional fuel pump, cooling fans and more. Suitable for use with most fuel injectors, or pumps and motors up to 10 amps. Kit Cat. KC-5382 supplied with PCB and all $ .95 electronic components. 24 Smart Fuel Mixture Display This new ‘smart’ version has a few additional touches such as, auto dimming for night driving, emergency lean-out alarm, and better circuit protection. Another great feature, is the ‘dancing’ display which operates when the ECU is operating in closed loop. Closed loop means that the air/fuel ratio is optimum for fuel economy & emission performance. Kit supplied with PCB and all electronic Cat. KC-5374 components. •Car must be fitted with air flow and EGO $ .95 sensors (standard on all EFI systems) for full functionality. 27 PRICES VALID TO END NOVEMBER 2005 Exclusive To Jaycar! This kit enables you to make a full-sized electronic scoreboard, in particular for Basketball but also adaptable for netball and other games. Ref: Silicon Ship March/April/May 2005. It can built for the fraction of the cost of commercial equivalents and has a completely wireless scoring console that can control one or multiple scoreboards. You can mount the scoreboard high up in the court plug it in to a 240VAC power point and then control them from a table courtside with no messy wiring. It features Home/Away team scores 0 to 199 game period, countdown time, Home/Away time and the addition of a new 'foul' feature. It measures 900 x 600mm and comes with all pre-cut scoreboard woodwork, screen printed face, display filters, mounting plates, pre-programmed microcontroller, printed circuit boards, 2.4Ghz transmitter & receivers, pre-punched control console with special piezo end-of-game quarter sounder, Cat. KC-5408 and all electronic components to $ make one scoreboard. Extra Scoreboards Available Contain everything included in the original kit without parts for the control console Cat. KC-5409 $649 799 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au SERVICEMAN'S LOG The fountain of all knowledge I think that servicing would be a good job if I didn’t have to fix things that were broken! OK, I’m just kidding but it’s certainly a job that has its moments. A TRICKY LITTLE Panasonic TC51S90A (MX5A chassis) waltzed its way onto my workshop bench with an irritating fault – it would turn itself off intermittently, when hot. I started by checking all the voltage rails but could find nothing suspicious. I then checked and changed all the small electrolytics in the power supply. That also failed to fix the problem and after checking for dry joints throughout the set (especially on the line driver transformer and the IC regulators), I had a go with the freezer. But even this refused to reveal the little blighter’s secrets! I subsequently spent an indecent amount of time with this set (more than it was worth, in fact) before realising that it might be the microprocessor. I checked the clock oscillator and the 5V reset line but became really suspicious when I was lucky enough to notice a slight drop in the 5V rail to pin 39 of IC1101 (MN1871681TFH). In addition, the supply IC regulator (IC850) was getting rather hot. However, before ordering a new microprocessor, I changed the IC Items Covered This Month • • • • • Panasonic TC-51S90A TV set (MX5A chassis) LG RT-54NA61RB rear projection TV set (chassis MP-03AB). Philips 29SX8761/75R TV set (G8 chassis) Toshiba Active Vision CT-90101 TV set (model 36ZP48P(B)) Hitachi C29F300B TV set (V3AL1 chassis) siliconchip.com.au regulator and the electrolytics on the supply rail. I then discovered that the impedance across this rail – which essentially feeds just the micro – was just 50W, even after desoldering the reset IC and pin 39. It didn’t take long to discover that the real culprit was 5.6V zener diode D1160, which was intermittently leaky. I replaced this and its sister D871 for good measure. LG rear projection TV A while back, we had an LG RT54NA61RB (chassis MP-03AB) rear projection TV which had three coloured dots at the top of the screen. This came in as a warranty claim and we soon discovered that the fault had occurred after the removalists had moved the set to a new location. At first, we thought this was due to some kind of screen burn but after removing the screen and displaying the picture on the ceiling, it was obvious that it was nothing to do with the tubes or electronics. Instead, it was soon traced to the mirror which had three tiny dimples in it. A new one was ordered and fitted, which fixed the problem. After the set had gone out, we examined the mirror to try and find out how the dimples had got there. Our suspicions were that the removalists had dropped something on the back and deformed the mirror. The mirror consists of a strong welded steel frame with pre-tensioned silver foil stretched out across it. Behind this is a polystyrene block packing filler. The interesting thing was that when we lifted the mirror so that it was face up, the dimples disappeared – they were only there, in exactly the same place, when it was pointing down! With some difficulty, we managed to prise out the polystyrene block but it was faultless. However, with the polystyrene removed, the dimples in the mirror had disappeared, regardless of its inclination. We then reinstalled the polystyrene block and the dimples were still not there. Our conclusion was that three specks of dirt or dust had embedded themselves in the polystyrene when the set was moved. When we removed the block, we displaced them and now it was all OK. The fountain of knowledge I used to supply technical advice and support to colleagues in this dwindling profession. I guess I found it flattering that someone out there doesn’t consider me to be total dill and generally speaking, what goes around comes around. Hopefully, when I have lost more marbles than I have left, someone might return the favour – that is, of course, if there are any technicians left in our increasingly “throw-away” society! Thomas, a sem-retired technician, wrote in from interstate with obvious frustration. He had a Philips TV in which he suspected a faulty P83CO54 microcontroller, which was no longer obtainable. He needed to know a little more about the I2C data bus so he could perhaps understand and maybe fix his problem (as yet undefined). I guessed that he was fixing a Philips 29SX8761/75R (G8 chassis) and suggested that before he went down the expensive and difficult road of getting a replacement IC7222 (Part No: 4822 00932 953) that he might try replacing the EEPROM (IC7223, 24C04), as it is much cheaper and often gives the same symptoms as the microcontroller. I briefly explained that the “Inter IC” (I2C) Bus is a twin bidirectional 7/8bit (10 fast mode) digital TV control communications system developed by Philips in the early 90s and now used in almost every TV set. One line November 2005  65 Serviceman’s Log – continued is the Serial Data (SDA) and the other is the Serial CLock (SCL) and these lines connect all the digital ICs to the microprocessor and EEPROM. The data is transmitted in this byte/ word format: Start condition, Slave address (to select the IC), Acknowledge, Sub Address (to select the function), Acknowledge, Data change (varies the function level), Acknowledge and P (= stop condition). The eighth bit determines the data direction R/W. The remainder are for I2C extensions (eg, RS232 Access bus protocols) and fast mode. I also suggested he check the following around this circuit: +5V, reset 5V and the clock crystal/resonator frequency. And he was advised to use a CRO to check for digital noise on the +5V, SDA and SCL lines and to check the error (clear first and then reread) 66  Silicon Chip and option codes (for this particular model). If something is wrong with these, you disconnect the data lines to each IC until the basic conditions are restored. Other checks included disconnecting the remote control receiver in case it was transmitting noise – the control keyboard is scanned and faulty switches can cause funny effects. Memory problems indicate problems in the EEPROM, while some sets have backup batteries that fail. Most microcontroller faults will not let the set power up. The way around this is to override the standby/on IC pin and then carry out the above checks. I suggested that he initially try the Service Mode switch (SW1907) and read the error codes. It was at this point he explained he had no picture or sound and was not able to read any OSD error codes in the Service Mode, nor was he able to discern any significant flashing of the Standby LED except to note that it was glowing yellow or orange. However, he did manage to conclude that there was activity on the SDA and SCL lines and they were normal at +5V DC. He also turned up the G2 control on the flyback transformer and found he had a fully-scanned raster with flyback lines but absolutely nothing else. IC7551 (TDA4681) was getting extremely hot so he replaced it but it made no difference. As we both had service manuals, we discussed various voltages and waveforms like sync pulses and sandcastle, etc and basically nothing was coming out of IC7551 on the Small Signal Board (SSB) to the CRT D Board. Thomas then discovered Q7186, R3181 and R3182 on the CRT board were also faulty but replacing them didn’t alter the symptoms. Eventually, I suggested he send me his CRT board and some of the ICs that he wasn’t sure about and I would install them in one of my own sets. This he did and apart from a small error on the CRT board, I found everything was OK except for IC7466 (TDA4651) which gave the same symptoms on my set as he had. And ironically, his EEPROM gave no sound. I sent the parts back, hoping these would fix all his problems. Unfortunately they didn’t. He was unable to get a TDA4651 but a TDA4650 didn’t work either. Finally, he sent the entire chassis to try in my set. I had to socket all the ICs in both sets in order to check them. Also, I found there were significant differences between his model and mine, which meant I couldn’t directly connect the Large Signal Panel into my set (and vice versa) without changes to plug L20 (pins 8 and 9), which gave no vertical deflection. In the end, I found that the fault lay on the SSB and I swapped all the ICs (except for the microcontroller), the tuner and the Sound H Board (which is soldered to the SSB. This made no difference, so it looked like the fault really was in the microcontroller. The problem was that the 42-pin high-density microcontroller IC could not sustain repeated desoldering and soldering. As a result, Thomas invested in some expensive 64-pin IC siliconchip.com.au I had a “recall” demanded by a client on a Grundig TV I had fixed three months earlier. Despite always pointing out that I can only guarantee the work I do and the parts used for a particular fault, I still get clients expecting me to guarantee the whole set after it has been repaired. Basically, they expect me to take responsibility for every aspect of their set’s subsequent performance – including self-inflicted faults. Of course, that’s impossible – it’s like asking a mechanic to guarantee all subsequent mechanical faults in your car after he’s repaired the brakes. This clown’s set previously had several dry joints in the deflection circuitry, which caused all sorts of sync and horizontal scanning problems. This time, however, he wanted a house call because he had a chrominance problem. When I arrived, he triumphantly demonstrated that there was a chroma delay problem, resulting in monosiliconchip.com.au www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com Coming the raw prawn ! W E ELEXOL Ether I/O 24 N www.elexol.com www.elexol.com www.elexol.com www.elexol.com UDP/IP-controlled digital input/output module featuring three 8-bit ports with 5V level signal lines. Each of the 24 lines can be independently programmed as either an input or an output. Connects to any TCP/IP protocol network. CT VIA CONNE TO TALK R ROUTE INTERNET TO ANYEVICE! D Supports ARP, BOOTP, DHCP, ICMP and UDP/IP protocols Standard 10BaseT Ethernet Interface; RJ45 connector 24 independently programmable signal lines with configurable CMOS, TTL or Schmitt Trigger thresholds and programmable pull-ups per line Easy connection by three 10-way box headers On-board 50MIPS flash micro-controller may be reprogrammed to suit specific applications Integrated switch-mode voltage regulator allows power supplies from 8-32VDC User 5V 500mA output to power external interface boards or sensors Compact module – 72 x 72 x 24mm Great range of I/O-24 peripherals, too ... CONNECTOR/ LED BOARD Provides screw terminal connections plus optional either pull up or pull down resistors and LED port status indication. OPTO INPUT BOARD Provides 8 Opto Isolated inputs for each of the I/O-24 pins with LED indication. RELAY OUTPUT SWITCH/PUSH BUTTON BOARD BOARD Provides 8 isolated relay contact outputs suitable for a variety of loads. Provides 8 switch/ push buttons with LED indicators showing the status of the I/O pin. Visit our web shop <at> www.elexol.com Elexol Pty Ltd Ph: (07) 5574 3988 Fax: (07) 5574 3833 (PO Box 5972, Bundall, Qld 4217) www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com www.elexol.com sockets from Radio Spares. I cut them up to fit the ICs and swapped them over. And that was it – his microcontroller IC, as he had predicted, was faulty, as mine worked fine in his chassis. Mine is a PC87C055 but the P87C054 is also still available from Philips. I sent the chassis back by post and Thomas refitted it to find everything was now OK. I also advised him that multiple failures – such as in this set – are due to things like lightning strikes, power surges or EHT flashover within the picture tube to either the CRT socket or the yoke. As a result, I suggested he clean the dust and dirt off the CRT, especially around the EHT final anode, and check the earthing to the yoke clamps. I also told him to fit two back-to-back series 24V zener diodes to the set, with their anodes connected to the P5 Aquadag and Link 9199 on the CRT D Board, respectively. Subsequently, he told me that he had another problem involving an audible “plop” or “thump” to all three loudspeakers when the set was switched on or off. although I never noticed this symptom when I had the chassis. The circuits in the service manuals show a variety of muting circuits that keep the set quiet when the power is switched off. His set had yet another variation and he changed a couple of electrolytics (C2676 and C2677) in this mute circuit from 22mF to 100mF, which reduced the problem to a level which was acceptable to him. Not being one to leave loose ends, I was intrigued with the problem and would like to have resolved it. However, I respected his decision to leave it alone! Apparently, the master on/off power switch doesn’t produce any noises, so presumably the problem only occurs in the remote control mode. This set is fitted with no less than six audio amplifiers, so was his problem confined to just three of them or all of them? The mute circuit monitors the 12V rail and mutes the set until this rail was either fully charged or discharged. The audio amplifier IC (IC7621, TA8218AH) that provides the left, right and sub-woofer channels uses a 23V rail instead. I don’t quite understand the circuit changes between the models but I would have changed C2620 to 330mF to give a longer time constant in the PLOP MUTE circuit. November 2005  67 Serviceman’s Log – continued chrome leading edges and coloursmeared trailing edges. This definitely was nothing to do with my previous work and had not been present when I had re-delivered the set 90 days earlier – as I was quick to point out. Mr “know-it-all” had the set connected to a brand-new set-top box, so I began by checking the set’s own OSD menu. This gave crisp, clear colour registration. Next, I connected an indoor aerial and tuned in a terrestrial station. That too came in without the colour delay. Finally, I demonstrated it with a video cassette and DVD. And again, the pictures on the set were perfect. By now, it was clear to me that the problem lay with the set-top box – which was still under warranty – and had nothing to do with the TV. It wasn’t so clear to the client, who felt that it was his God-given right to call me out on this for free. The British Toshiba George Barrington-Smythe was fresh off the boat with his brand new Toshiba “telly” from the Old Country. This was a Toshiba Active Vision CT90101 model 36ZP48P(B) with a Mitsubishi W86LXK003X30 picture tube. What poor George hadn’t realised is that Toshiba TV sets in the UK are entirely different from the models imported from Japan by Toshiba’s agency in Australia (Castel). Nor did he realise that the Earth’s magnetic field is significantly different Down Under – at least, in terms of its orientation. 68  Silicon Chip Still, he tackled the inevitable colour purity problem he was getting with true traditional British stiff upper lip. He had already had another technician around to his flat, who degaussed the tube. Unfortunately, this had only helped to reduce the symptoms slightly. Furthermore, this technician had now gone home to China as prospects are better there for TV technicians! How times have changed! Anyway, he phoned me and asked what could be done, “my good man”. I explained that the Earth’s magnetic field, being different in the southern hemisphere, was the basis for his problems. I also explained that problems could be caused by other magnetic sources, like the steel RSJs in his unit or even hifi loudspeakers and little kids with high-power magnets. Most of this stuff he dismissed but I did suggest two practical plans of action to prove my claim and possibly fix the problem. First, I told him to rotate the set through 90° relative to its current position and see if the colour patches moved. And second, I told him to find the geometric adjustment in the set’s on-screen menu, as this can also affect the colour purity. He duly followed both suggestions but neither gave any real improvement to the colour purity. In the end, I said that there was nothing for it but for him to bring this 76kg British set into my true-blue workshop. There, I could check the set’s own degaussing circuit to see if that was OK. If that failed to turn anything up, the picture tube would have to be rotated through 180° – ie, mounted upside down. I explained that the latter would be expensive in terms of labour but our man was made of sterner stuff and brought the set in. The problem was quite evident when it was on my bench, the set displaying prominent colour patches. I unplugged the degaussing coils, switched the set on and degaussed the screen manually with my wand. I also tried the geometric menu myself but nothing would shift the patches. I was now faced with a dilemma – should I first try to realign the deflection yoke and purity magnets or just dive straight in and rotate the picture tube? I settled on the latter. If it didn’t work, I could then redo the set’s purity. The logistics of turning the tube upside down are considerable and require military precision. First, I needed at least four telephone books and an assistant to help with the lifting. Next, the back and chassis were removed, after which we carefully lowered the screen so that it sat face down on top of the telephone books. That done, the 10mm coach bolts were removed and the front of the cabinet lowered gently to the bench around the books, leaving the CRT. We then rotated the tube 180° and lifted the cabinet back up and refitted the bolts. The next problem I had was extending the degaussing and geomagnetic coils to reach their respective sockets. I also cut and resoldered the deflection yoke wires, so that the picture would be the correct way around, before refitting the chassis. And that was all that was required to resolve the purity – no further adjustments were needed. All that remained was to extract the money from George Barrington-Smythe’s wallet. Dead Hitachi I was called out to a dead 3-year old Hitachi on the third floor of a home unit. It was an Hitachi C29F300B (V3AL1 chassis) but Mrs Tracy had it in the middle of a huge wooden cabinet in her lounge. The set was chosen because it almost exactly fitted the cabinet hole and while it looked great, it was a nightmare to fix because of the logistics. For a start, the power point was unreachable without pulling out the entire unit. The TV set then had to be partly eased out of the cabinet and swung around, with the added constraint of all the AV leads that were connected to the rear. Eventually, by half-balancing it on the edge of the wall unit, I managed to get it into a position where I could remove the back. It was at this moment that the battery in my trusty Panasonic electric screwdriver chose to go flat and I didn’t have a spare. This meant that I had to manually remove all the screws (and there’s lots of them), while balancing the set with my knee and other arm. And to make it even harder, the screws are black and are recessed into invisible deep black holes. siliconchip.com.au LED Light Fittings Wall Mount We stock a complete range of especially selected quality light fittings for most applications. These fittings complement our LED-based MR16 lamps and are factory assembled for long life operation. Direct connection to 12V (AC or DC) makes these lights ideal for back-up or emergency lighting and for use in low-power (energy saving) systems. All light fittings are supplied fully assembled and fitted with 3Watt High-Power LEDs, withlow power consumption, typically 300mA <at>12V Ideal for Caravans, Motorhomes, Boating and Camping applications. Various colours and types – - Bullet - Square - Round in Gold - Chrome - Satin Chrome - White - Black. Please view website. Waterproof/ Outdoor Various types available – - Brass - Bronze - Stainless Steel - Black - Green Ceiling Mount (Stainless Steel) We also stock a full range of other Ceiling, Wall mount and Outdoor type light fittings. Please visit our web site to view a full and detailed colour brochure of all fittings available and request further information. Hi-Output MR16 LED LAMPS Uses 3 Watt Hi-Output LED with Expected Life 50,000 hours plus Input 12-24VDC or 12-18VAC (low power consumption, 300mA <at>12V) Up to 60 Lumens light output Wide beam angle 110° (Narrow beam angle available soon) Total height 39mm (+ Pins) (colour changing longer) Standard 50mm diameter. Drop-in for MR16 lamp housing No UV or Heat radiation (Run much cooler than standard halogens) Conforms to IEC, CE & EN standards For use with “iron core” transformers (electronic type not recommended) Once the back was finally off, it didn’t take long to find that the main fuse (F901, 4A) had blown violently. I unplugged the AC power before replacing the fuse and then reconnected it before switching the set on. Much to my surprise, the set fired up and everything seemed OK. That bothered me because this fuse didn’t blow without reason. Of course, it could have been a power surge but nothing else had been damaged in the unit. Anyway, the set was working now so there was nothing could I do but replace the back and push the set back into position. siliconchip.com.au This process took some time but eventually the job was all done. I then switched the set on to check that all was well and the fuse immediately blew again! You get days like this! There was nothing for it but to start over and track down the real fault. There were several possibilities but the most likely suspect was a faulty degaussing coil PTC. After removing the back again, I unplugged the degaussing coils and fitted a new fuse before switching on and off several times. So far, so good – the set was still working OK (or was it a bit like the guy who fell off the Empire COLOURS: 3 Shades of white & 10 colours available: Sun White, Cool White, Warm White, Red, Amber, Orange, Purple, Magenta, Green, Grass Green, Blue, Light Blue, Cyan PLUS: Multicolour changing lamp with RGB LED (cycles through various Red, Green, Blue colour changing routines) Colour control option via IR Remote or RS485. Fully Dimmable State Building and had fallen 20 floors – so far, so good!). I then reconnected the degaussing coils and switched on again – the fuse blew immediately. The only way I could repair this set now was to take the chassis to the workshop and order and fit the correct PTC thermistor (TH901, Part No. 2341325) and then bring it back. And this time it all worked. Of course, the diagnosis and repair was relatively simple compared to the logistics of the exercise. As far as I am concerned, I mainly earned my money for patience and persistence, rather SC than the repair itself. November 2005  69 By TRENT JACKSON S erial I/O controller & analog sampler Looking for an easy-to-drive I/O controller? This unit connects to the serial port of your PC and can be programmed to switch relays, dependent on voltage, resistance, temperature and digital inputs. It also includes comprehensive system timers to control the relays and you can set the system up to operate as a PLC-style controller. PC-based serial I/O controllers and analog samplers are hardly new. However, this 10-bit unit has some special features that are normally hard to come by in a DIY unit, including closed loop control (as in a thermostat), spreadsheet logging, programmable I/O logic control, and temperature and light 70  Silicon Chip sensing. It also includes real-time system timers that can be used to control two on-board relays. Speaking of relays, you can also define “less than” or “greater than” values in the software to control them. This can be done for any of the input variables – temperature, LDR resist- ance, analog voltage inputs and digital inputs. For example, you could set one of the relays to switch on if the temperature goes above say 20°C and this could then control a fan or some other item of equipment. In short, there are lots of possibilities, especially as the unit can also be directly interfaced to other CMOS circuits. You can also quite easily create your own software to control the heart of this project which is (of course) a microcontroller – in this case a PIC! This particular PIC is a 40-pin 16F877A “power plant”, boasting 8K of flash memory, 256 bytes of RAM, eight analog inputs, 256 bytes of EEPROM memory and lots of other features. In operation, the PIC communicates with your PC via a serial port. You can siliconchip.com.au a preset period ranging from 1-999 seconds. In effect, it’s basically a mini low-speed oscilloscope – see Fig.1. The output port can be directly written to by clicking the D0-D9 output lines on the software interface (to set the data value) and then clicking the <Write Data To Port> button. Alternatively, the data value can be entered by directly typing it in, in either decimal or hexadecimal format. It’s the PC software that really makes this project. However, this software would be of little use without the PIC microcontroller – it generates all the analog and digital ports and converts all the data on these ports into a serial data stream for the PC. Logging as well Fig.1: the Serial I/O Controller is controlled by Windows-based software. This is the main GUI (graphical user interface) – check out “The PC Software At A Glance” section for a rundown on all the functions. Features & Specifications Rugged 10-Bit Digital Input Port (0-16V) Temperature Accuracy: ±1°C 0-5V & 0-25V Analog Voltage Inputs On-Board System Timers Plus Buzzer Temperature & Light Sensing (LDR) Inputs 32-bit Windows-Based Software High-Current 10-Bit Digital Output Port Full Function SpreadSheet Logger Closed Loop Control Using Two Relays CRO-Style Analog Graph Plotter Serial Interface (2400 bits/s, Inverted) Combination I/O “AND OR” Logic connect it to the PC using either a serial cable or a USB-to-serial adaptor. It’s worth noting that there are not many DIY serial-based 10-bit I/O controllers “out there”, most being parallel port-based. The downside to using the serial port is that it is a bit slower. However, given the fact that all data is updated about four times a second, it isn’t all that bad. Faster speeds can be obtained if you click on the “Dedicated Fast Update” option in the software. In this mode, the variable that you select is updated at a rate of about 20 times a second. Once again, any of the data elements can use this mode, including temperature, analog inputs, digital inputs and LDR resistance value. The serial rate is 2400 bits/s, which is fast enough for siliconchip.com.au the job and works reliably. The system can also be set up to function as a “PLC-style” controller. You can program it via the accompanying Windows software to accept a certain decimal value from the input port and in turn write a pre-defined value to the output port. With 1024 combinations to play with, there’s lots of logic control that can be used for your applications. The input values, along with temperature and other analog values, can be assigned to control either of the two onboard relays. A buzzer is also included – eg, to sound a warning when certain preset thresholds are exceeded. Also included is an analog plotter. This can be set to plot a graph of the data element that you select over The data logging side of things can handle up to 1000 samples. You can set the sampling time anywhere from 1-999 seconds, which means that this unit is suitable for long-term data acquisition. All analog inputs have 10-bit resolution, which equates to a step size of about 5mV (ie, 5/1023). As a result, the temperature readout is capable of displaying 0.5°C changes. The first analog input has a range of 0-5V and the second 0-25V (with a resolution of 25mV). Provision has also been made for measuring resistance and there is an on-board LDR that changes resistance according to the light level present. You could replace this LDR with some other resistive device if desired. As stated previously, thresholds for this variable can also be set in the software to control the relays. Circuit details Fig.2 shows the block diagram of the I/O Controller, while Fig.3 shows the full circuit details. The circuit is dominated by the PIC16F877A microcontroller, which is clocked at 4MHz using crystal X1 and two 22pF loading capacitors. This particular microcontroller was chosen mainly for its pin count, rather than for its 8K of program code space. In fact, the code occupies a mere 1K of memory for this project! All but two pins on the 40-pin PIC micro are used, including four for A/D inputs, 20 for I/O lines, two for serial data transmission, two to control the relays, one for a buzzer and two for the TX/RX lines. Of course, November 2005  71 and RC7 (pins 25 & 26). At all times, the software in the PC calls the shots. The PIC micro “sits back” and waits for a command on the serial port with the format “Sync Byte, Function” – see the Control Code panel for further details This makes it very easy for custom software to be developed for this project and in fact, the whole idea was for it to be as universal as possible. A complete list of all the function commands is provided with this article. Other circuits could easily be adapted to interface to this controller, including PICAXE circuits. The microcontroller software for this project was written using PIC Basic Pro, which is a true compiled high level BASIC language with similar commands to the PICAXE. The source code will be available as a free download from the SILICON CHIP website at www. siliconchip.com.au. Fig.2: the PIC microcontroller (IC1) dominates the hardware side of the I/O Controller. It generates all the analog and digital ports and converts all the data on these ports into a serial data stream for the PC. this could all have been done with (say) an 18-pin PIC16F628 plus a few discrete ICs. However, the 16F877A microcontroller has a price tag of just $10, so why bother? As shown in Fig.3, the output port consists of two ULN2003 Darlington open-collector driver ICs (IC3 & IC4), along with 10 LEDs (LEDs5-14) and their associated 330W current-limiting resistors. The LEDs draw about 10mA each, which is well within the capabilities of the ULN2003 drivers. In fact, these drivers can provide sink currents of up to 500mA per line (although this must be derated when more than one line is active), so there’s still plenty of “headroom” to connect your own “goodies” to this port. The LEDs hanging off this port actually have two functions. First, they give an obvious indication as to the status of the data lines (ie, which bits are set). And second, they act as pullups for the open collector outputs of IC3 & IC4. As a result, this port can be directly interfaced with other logic circuits (both TTL and CMOS). Note that because of the LEDs, the outputs are no longer open collector. 10-bit input Want a 10-bit input as well? No 72  Silicon Chip problem – that’s provided by lines D0D9 on ports RD0-RD7 and RC0-RC1. These lines feature zener diode clamping (ZD1-ZD10), which means that up to 16VDC can be applied. In practice, 3.5-16V is the valid range for a logic high, while 0-2V is the valid range for logic lows. Values between these two ranges can be read as either high or low, depending on where the threshold is. As shown, a 1kW resistor, a 100nF capacitor, a 5.1V zener diode and a 100kW pull-up resistor are connected to each input line. The zener diodes clamp input voltages that are greater than 5.1V, while the 100nF capacitors and associated 1kW resistors act as filters. The 100kW resistors have two functions. First, they act as pull-down resistors when the input lines are floating and second, they discharge the 100nF capacitors when the logic states change, so that the RC time-constants remain valid. Data communication is achieved via the serial port and an RS232 interface based on IC2, a MAX232 serial data buffer. The external transmit (TX) and receive (RX) signals are on pins 13 & 14 of IC2 respectively, while the PIC micro communicates via ports RC6 A/D converters Four out of the eight available 10bit A/D converters inside the PIC are used in this circuit – one for sensing temperature via an LM335Z precision temperature sensor, one for measuring the resistance of an LDR (or some other variable resistor) and two for measuring the 0-5V and 0-25V analog voltage inputs. The relevant inputs are ports AN0AN3 on the microcontroller (pins 2-5). The LM335Z temperature sensor is connected to AN0, the LDR to AN1, the 0-5V analog input to AN2 and the 0-25V analog input to AN3. All calibration for these measurements is done via the Windows software provided. For example, temperature measurements are accurate to ±1°C after proper calibration. Considering that the A/D converter is 10-bit and the LM335Z output varies by 10mV/°C , this figure is to be expected. Calibration for the 0-25V input is achieved using both the software and a 100kW trimpot (VR1). This trimpot, and its associated 330kW resistor function as an adjustable voltage divider. In practice, VR1 is adjusted to provide a division ratio of 5:1. The best way to do this is to apply a precise 12.5V to the input, run the PC software and adjust VR1 until you read 12.5V on the screen. Further fine tuning can then be done via software. Properly calibrated, this input is siliconchip.com.au siliconchip.com.au November 2005  73 Fig.3: this is the full circuit diagram of the Serial I/O Controller. The PIC microcontroller (IC1) accepts the analog and digital inputs and generates outputs to drive the relays (via Q1 & Q2) and the digital output port (via Darlington arrays IC3 & IC4). It also interfaces with the serial port via a MAX232 serial data buffer (IC2). THE PC SOFTWARE AT A GLANCE T HE SOFTWARE for the I/O Controller has been tested with Windows XP and Windows 98SE but should also work with Windows 95, Windows 98 and Windows 2000. It has four main interfaces: (1) the main GUI (designated Multi Function IO Controller); (2) Data Logging; (3) IO Logic Control; and (4) Alarms & Timers. The last three are accessed via the main interface by clicking on the menu items. Most of the control is retained within the main GUI. This has a host of options which range from displaying the values of all the data elements, a graphical analog plotter, closed loop control, and input and output data control. In addition, there are a number of command buttons in the bottom righthand corner that perform various tasks (all of which are selfexplanatory). The first step in getting it working is to find an available Comm (serial) port on your PC and click the “Connect” button”. A communications link will then be established. After that, it’s simply a matter of setting up the system to perform the required task. The accompanying breakout boxes give further details. THE INPUT VALUES (ie, Temperature, LDR Resistance and Analog Input 1 & 2 voltages) are clearly displayed here. DATA CAN BE WRITTEN to the 10-bit output port by clicking on the D0-D9 “LEDs” or by entering in a decimal or hex value and then clicking the <Write Data To Port> button. CLOSED LOOP CONTROL: this section lets you control either relay 1 or relay 2 (or both), according to an input variable (voltage, resistance or temperature). Here, for example, relay 1 has been set up to switch on if Analog Input 1 is less than 2.75V and to switch off if Analog Input 2 goes above 3.5V. Similarly, relay 2 switches on if the temperature is less than 20°C and off if the temperature rises above 22°C (ie, it could be used as a thermostat). However, you have to be careful not to overlap conditions – eg, setting relay 1 to switch on of Analog Input 1 is greater than 3V and off if it goes above 2V would cause erratic operation by toggling the relay on and off continuously. Note that all data is automatically saved when you exit the software. 74  Silicon Chip THIS SECTION lets you select which input variable to plot. Clicking the down arrow lets you choose which input variable to use for closed loop control. ANALOG CRO-STYLE GRAPH PLOTTER: this nifty little window shows the history of any input variable that you select by plotting a graph. You can define the update rate anywhere between 1-999 seconds. Alternatively, for faster speeds, you can select the fast update mode option that’s located right at the bottom of the window. In this mode, the plotter is updated at about 20 times a second. Make sure you remember to enable this function by placing a tick in the “ON” box. Plotter scaling is fully automatic for each element. siliconchip.com.au DATA LOGGING: you name it you can log it – Temperature, LDR resistance, Analog Input channel 1 or 2, 10-bit input data . . . the choice is yours! What’s more, you can set the logging interval from 1-999 seconds and up to 1000 individual logs can be recorded. There’s also a facility to automatically save logged data at a specified interval, to retain data in the event of power failure. The “auto-log” file is stored in the program’s applications folder and can be opened in any text editor. Other features include: save, open and print capabilities; logging with or without date or time; the ability to auto-clear the log sheet after 1000 samples have been recorded; and the ability to change the input variable on the fly. The log sheet scrolls automatically as new data is logged. Once the log is full, a red “LED” flashes to indicate that you need to save or clear the log so that new data can be recorded – just click on the “Clear Log” button or select “Start New” under the logger menu. THE COMBINATION IO LOGIC CONTROL dialog allows you to set the unit up to function as PLC-style controller. To assign values, just type the data in (in decimal or hex format), or click on the data lines. Do this for the input & output values and click on “Add To List”. You can save, open and print all logic scripts. And there are a few options that allow you to manipulate the logic – invert, XOR and latch. With latching, the output remains in its last state until a new input condition has been detected. Without latching enabled, the output port will be cleared once the input value has been removed. After you create or open a script, be sure to enable it by ticking the “Enable Logic Script” box. When a script is active, a virtual red “LED” next to the SILICON CHIP logo flashes. The response time is about 250ms for normal update all data mode and 100ms for dedicated fast update sampling mode. THE ALARMS & TIMERS INTERFACE has a vast array of timer parameters & buzzer alarm settings, most of them self-explanatory. The main thing to keep in mind is that the time format for the timers is 24-hour mode and must include all digits – ie, trailing zeros. All settings are automatically saved to a configuration file each time the program closes. These settings are then automatically loaded each time the program executes at start up. Deselecting the “Use Date” option allows the timers to be cycled on a daily basis (rather than just the programmed dates). The buzzer alarm conditions are located at the very bottom and you can use any data element you wish. There are three separate conditions – make sure that none of them overlap. siliconchip.com.au November 2005  75 Fig.4: install the parts on the PC board as shown here but don’t install the PIC microcontroller until after the power supply has been tested (see text). Take care to ensure that all polarised parts are correctly oriented and be sure to take the usual precautions against static electricity when handling the ICs. Note that the relays are capable of switching low voltages (up to about 50V DC) only. Table 1: Resistor Colour Codes o o o o o o o o o o o No. 1 1 1 11 3 3 1 10 13 1 76  Silicon Chip Value 470kW 390kW 330kW 100kW 10kW 4.7kW 2.2kW 1kW 330W 180W 4-Band Code (1%) yellow violet yellow brown orange white yellow brown orange orange yellow brown brown black yellow brown brown black orange brown yellow violet red brown red red red brown brown black red brown orange orange brown brown brown grey brown brown 5-Band Code (1%) yellow violet black orange brown orange white black orange brown orange orange black orange brown brown black black orange brown brown black black red brown yellow violet black brown brown red red black brown brown brown black black brown brown orange orange black black brown brown grey black black brown siliconchip.com.au very stable and quite accurate. In fact, you could use it as a second meter for measuring DC voltages up to 25V. Diodes D4-D7 provide over-voltage protection for each of the four input channels (within reason). They do this by clamping the input voltage to the supply rail if it rises above 5.6V. The 100nF MKT capacitors on the inputs are rated at 100V, while the input impedance is a respectable 390kW. Basically, the two analog inputs should be able to cope with inputs up to about 50V DC. Diodes D4-D7 also eliminate any positive or negative-going spikes due to pulsed DC inputs. ADCs in PIC micros aren’t very tolerant when it comes to glitches on the input being measured, so it’s necessary to eliminate these. Ports RE0 & RE1 on IC1 are used to control the on-board relays via buffer transistor stages Q1 & Q2. A 1N4001 diode is included across each relay coil to protect the driver transistors from any back-EMF that may be generated when the relays switch off. LEDs 1 & 2 indicate the status of the relays – ie, LED1 is on when Relay1 is on and LED2 is on when Relay2 is on. Port RE2 is used to switch the buzzer via transistor buffer Q3. This buzzer can be used to warn of certain conditions, as set via the software. For example, it could be set to turn on if the ambient temperature rises above a certain level. Alternatively, it could by programmed to sound if the analog voltage reading on Ch1 falls below a critical threshold. It could even be set up so that it sounds only when a combination of two or more variable conditions are breached. Port RA4 is used to pulse LED3 to indicate TX/RX activity. This occurs in real-time and if this LED isn’t flashing, then it’s likely that there’s no communications link between the controller board and the PC. It doesn’t tell you where the fault is though – it could be on either side (or on both). Temperature sensing Let’s now see how the LM335Z temperature senor operates. At 0°C, this device produces 2.73V between its centre pin and ground. This voltage increases by 10mV for each 1°C temperature increase. As shown, the LM335Z is forwardbiased via a 4.7kW resistor, which siliconchip.com.au Fig.5(a): here’s how to connect a relay to any of the 10 digital output lines (D0-D10). The diode must be soldered directly across the relay terminals (be sure to get it the right way around). Note that you must remove the indicator LED from the output line (otherwise the reverse voltage rating of the LED will be exceeded). Fig.5(b): if the current required to drive the relay is more than the ULN2003 can handle, a transistor buffer can be added as shown here. This circuit will switch at least 500mA. Note that you must remove the indicator LED from the output line (otherwise the reverse voltage rating of the LED will be exceeded). Both these circuits can be powered from an external 12V regulated plugpack supply. ensures enough current to produce a reasonably accurate measurement. A 100pF capacitor and 470kW resistor filter the output voltage from the sensor, which reduces toggling of the least significant bit that is common to most ADCs – ie, when the voltage level is right on the threshold of a step. This effect is further cancelled out via the software. The calibration can be tweaked by changing the value of the 470kW resistor. A higher value will increase the temperature reading and vice versa. If you play around with the calibration enough, you could probably obtain ±0.5°C accuracy. provide some hysteresis across the 10kW resistor. Note that this input can be calibrated as well and as mentioned earlier, you can use it to measure other resistive devices as well. Be careful though – there’s no input protection. Light sensing Construction LDR1 performs the light sensing operation. It’s wired in parallel with a 100kW resistor, to bring its low-light level value down to around 90kW. The resulting voltage across the series 10kW resistor is proportional to the light level and this is applied to port AN1. In the software, the 10kW resistor is treated as part of a voltage divider. Once the voltage across it is known, the LDR’s resistance can be calculated to give a value in ohms (the parallel 100kW resistor is taken into consideration for this calculation). The two 1mF tantalum capacitors connected to AN1 ensure stability and Construction is quite straightforward, with all parts mounted on a single PC board coded 07111051 (161 x 160mm). Fig.4 shows the assembly details. Begin by installing the 34 wire links. Some of these are quite long and are close together, so make sure they don’t short together. Note also that two of the links go under the microcontroller (IC1). Once these are in, install the resistors in the locations shown. Table 1 shows the resistor colour codes but you should also check each value on your multimeter before installing it. Follow these with Power supply Power for the circuit is derived from a 9-15V DC supply (eg, a plugpack), with diode D1 providing reverse polarity protection. This feeds regulator REG1, which delivers a +5V supply. The associated 220mF capacitor on the input and the 10mF and 100nF capacitors on the +5V rail provide filtering and decoupling. November 2005  77 CONTROL FUNCTION CODES W ANT TO WRITE your own control programs? Here’s how a basic rundown on how the control codes work, together with a list of all the codes that control the system. During normal operation, the PIC “sits back” and waits for a command. When a valid command is received, it’s immediately executed and the PIC then goes back to its main internal loop and waits for another command to be issued (Fig.7). The first byte of data that the PIC expects to receive is an “a” in the data string. This “a” is the sync byte and is commonly used to indicate the start of a string. It also greatly reduces errors in the transmission, while also reducing the amount of code FUNCTION COMMAND STRING required in reading the actual data. Read Temperature “a” + CHR$(1) As stated in the article, it’s easy to interface other circuits to this controller. Read LDR “a” + CHR$(2) Due to its simplicity, you could even use Read Analog Ch1 “a” + CHR$(3) an 8-pin PICAXE micro to control it, in turn giving a huge number of I/O pins to Read Analog Ch2 “a” + CHR$(4) play with. Toggle Relays “a” + CHR$(5) The first step is to issue the controller Activate Buzzer “a” + CHR$(6) with a command string, telling it what function you want processed. Depending on Read 10-Bit Inputs “a” + CHR$(7) the function, you then issue another comWrite Port Data “a” + CHR$(8) mand to define the action to be taken. For example, if you want the “Read Temperature” function, then 50ms after you issue this command, it will to read the voltage at the output of the LM335Z temperature sensor. Following A/D conversion, this value will then be output as a serial data string to the serial port. On the other hand, if you issue the “Toggle Relays” command, it will then wait for another command to tell it which relay to toggle (Relay1 or Relay2), followed by the state of the relay – ie, ON or OFF. In the case of a data string, it’s either a 0 or a 1. After A Command Is Sent Now let’s see what happens after a command has been sent. We’ll take each command in turn. READ Temperature Command – at least 50ms after this command has been issued, the following string will be sent out: [“a” + #VCC Step Value + “<at>”] As previously mentioned, the “a” is the sync byte and – in the case of the controller talking back – it also sends out an end of string sync byte. The #VCC Step Value will be a decimal number ranging from 0-1023 which equates to 10-bit binary. At the receiving end, you will need to convert this value into temperature (as in the PC software provided). The analog converters are all 10-bit, so the step size is 4.887mV. The decimal value represents the number of steps. The best way to go about converting these values is to use tables rather than calculations. Temperature, LDR, Analog Channel 1 & 2, Input Port Commands – at least 50ms after this command has been issued, the following string will be sent out: [“a” + #Decimal Value + “<at>”] Toggle Relays Command – at least 50ms after you have issued the select function command, you must then issue this string to define which relay is to be used and its state (ON or OFF): [“a” + CHR(Relay Number) + CHR(State)] Note that the “Relay Number” variable must be in the range of 1-2, while the “State” variable must be either a 1 or 0 (all in ASCII). Activate Buzzer Command – at least 50m after you have issued the select function command, you must then issue this string defining the state of the buzzer (ie, ON or OFF, 1 or 0): [“a” + CHR(State)] Write Port Data Command – at least 50ms after you have issued the select function command, you must then issue this string defining the value of the output port (range 0-1023): [“a” + CHR(Port Value)] 78  Silicon Chip Fig.5: the calibration dialog lets you enter offset values, to accurately calibrate the four analog input channels. Once you enter in an offset, the related element is updated instantly. You then click on “OK” to save these settings to disk, which are automatically restored the next time you run the program. the diodes and LEDs, taking care to ensure these parts are installed with the correct polarity. The capacitors can go in next, again taking care with the polarity of the tantalum and electrolytic types. These can then be followed with the two miniature relays, the buzzer, the screw terminal blocks and the IC sockets. Now install the three BC548 transistors (Q1-Q3), followed by the LM335Z temperature sensor. This sensor comes in a similar package to the transistors so don’t get them mixed up. The LM7805 regulator is mounted with its metal tab flat against the PC board. To do this, first bend its leads down through 90° about 4mm from its body, then secure it to the board using an M3 x 6mm machine screw and nut and solder its leads. The 4MHz crystal is also mounted flat against the PC board – just bend its leads through 90° and push it all the way down onto the board before soldering its leads. It’s then secured in place using a wire loop which is soldered at either end to the PC board and also to the top of the metal case (this also connects the case to ground). Trimpot VR1 and the LDR can now be installed. The latter can be mounted about 10mm proud of the PC board, with its leads sleeved in spaghetti insulation so that they don’t short together. That done, you can install the three 16-pin ICs into their sockets, making sure the MAX232 chip is siliconchip.com.au Par t s Lis t 1 PC board, code 07111051, 161 x 160mm 11 PC-mount 3-way screw terminal blocks, 5mm spacing 1 PC-mount 2-way screw terminal block, 5mm spacing 2 SPDT PC-mount 5V DC Mini relays 1 mini PC-mount piezo buzzer 1 100kW horizontal trimpot (VR1) 1 light dependent resistor (LDR1) (Jaycar RD-3480, DSE Z-4801, Altronics Z-1619, or equivalent) 1 4MHz crystal (X1) 1 PC-mount DB9F connector 1 serial cable 1 500mm-length tinned copper wire (for links) 3 16-pin IC sockets 1 40-pin IC socket 5 M3 x 6mm screws 1 M3 nut 4 M3 x 12mm tapped spacers 1 set of self-adhesive labels Fig.7: this is the basic flowchart for the PIC software. In operation, the instructions are executed sequentially, after which the microcontroller returns to the “Main Wait For Command Loop”. used for IC2. Check that these devices are all oriented correctly and be sure to observe the usual precautions to prevent damage from static electricity. Initial checks All parts should now be in place except for the PIC microcontroller (IC1) – that’s left until the power supply has been checked out. First, check the assembly carefully to ensure that all parts are in their correct locations and that all polarised parts are correctly oriented. That done, apply power and check the voltage at the output terminal of the 7805 regulator – you should get a reading that’s close to +5V with respect to ground. This same voltage should also be present on pins 11 & 32 of IC1’s socket. If all is well, switch off and install siliconchip.com.au IC1 (notched end towards IC3 & IC4). You’re now ready to put your new I/O Controller through its paces. Don’t forget to set VR1 as described earlier. To drive the system, you can either use the Windows-based software or you can write your own control programs. The Windows-based software is easy to drive – just take a look at the accompanying screen grabs and the explanatory notes. For those who wish to write their own software, the control codes are listed in a separate panel. Finally, note that the on-board relays are suitable for switching lowvoltages only – eg, up to about 50V DC. DO NOT use them to switch mains voltages (ie, 240VAC). The board is not designed to do this and it would SC be much too dangerous. Semiconductors 1 PIC16F877A microcontroller programmed with IO.hex (IC1) 1 MAX232 serial transceiver (IC2) 2 ULN2003 Darlington arrays (IC3, IC4) 3 BC548 NPN transistors (Q1-Q3) 1 LM335Z temperature sensor (TS1) 1 LM7805 voltage regulator (REG1) 3 1N4001 diodes (D1-D3) 4 1N914 diodes (D4-D7) 10 5.1V 0.5W zener diodes (ZD1-ZD10) 2 5mm red LEDs (LED1, LED3) 2 5mm green LEDs (LED2, LED4) 10 3mm red LEDs (LED5-LED14) Capacitors 1 220mF 25V electrolytic 6 10mF 16V electrolytic 2 1mF 16V tantalum 16 100nF 100V MKT polyester 1 100pF 50V ceramic 2 22pF 50V ceramic Resistors (0.25W, 1%) 1 470kW 4 4.7kW 1 390kW 1 2.2kW 1 330kW 10 1kW 11 100kW 13 330W 2 10kW 1 180W November 2005  79 XL-02 Towers These high-performance tower speakers are very easy to build since no carpentry or soldering is required. The cabinets are precision-made and finished from 25mm medium density fibreboard (MDF). Virtually all you have to do is to install the speakers and the crossover network and fit the base panel. T and with aluminium formers, giving a quoted peak power ower speakers are certainly popular and they have handling spec of 1000W for a 10ms tone burst. a number of advantages in today’s homes and home The woofers are also magnetically shielded, by virtue of units. their double magnets and speaker basket construction. Because of their slim design, they occupy little floor The tweeter is a soft dome combined with a shallow space and even though they are tall, they do not dominate horn and the voice coil is ferro-fluid cooled for high power smaller rooms. And because of their height, their drivers operation. In fact the tweeter has a nominal power rating are at about ear level for most people when they are seated. of 200W (for high frequencies). Note that the tweeter is not These tower models from Delta Loudspeakers each emmagnetically shielded. ploy two 6.5-inch drivers to handle the bass and midrange Fig.1 shows the crossover network which is drawn in two while the 28mm dome tweeter handles frequencies above sections to reflect the way 3.5kHz. Specifications in which it is wired across The tweeter is mounted the four terminal panel on between the two midrange/ the rear of the speaker. bass drivers in the so-called Frequency response ............38Hz to 18kHz within ±2.2dB The two pairs of termiD’Appolito configuration,            (1/3 octave smoothed) nals are normally strapped often used in tower speakNominal impedance.............7.5W (see impedance curve) in parallel for connection to ers, and reputed to give Sensitivity............................93dB/1W <at>1m an amplifier but they may improved stereo imaging for Power handling....................200W separated for bi-amping, if seated listeners. desired. Both the woofers and Crossover frequency............3.5kHz Both bass and treble sectweeter are sourced from Crossover slope...................6dB/octave tions of the crossover have the Israeli manufacturer Dimensions..........................212 x 1235 x 215mm a 6dB/octave slope above Morel. The woofers are Mo           (not including 260mm square base) (or below) the nominal rel MW168H drivers with Weight.................................39.5kg each crossover frequency of huge voice coils – no less 3.5kHz and both feature than 73mm in diameter – Design by Michael Gayler 80  Silicon Chip siliconchip.com.au siliconchip.com.au November 2005  81 UPPER C1 + 6.8 µF 250V UPPER 5.6 Ω 5W R1 2.2 µF 250V C2 – LOWER TWEETER – + MOREL DMS371 L1 + 0.33mH LOWER – 15 Ω 5W R2 4.7 µF 100V C3 WOOFER 1 WOOFER 2 + + – – MOREL MW168H MOREL MW168H Fig.1: there are actually two crossovers – normally they are in parallel but they may separated for bi-amping. The crossover network is wired onto the back of the speaker terminal panel. The air-cored inductor is installed inside the cabinet. This pre-production sample has soldered connections to the speaker wires. Production versions have spade connectors. impedance equalisation by virtue of the RC network across each driver. Both woofers are connected in parallel, which is best for optimum damping effect from the driving amplifier. It also has the apparent effect of increasing the sensitivity by 3dB, by dint of the doubling of power for a given signal level from the amplifier. Perhaps the most unusual feature of these tower speakers is the arrangement of the venting in what is a bass reflex system. Instead of having a relatively small diameter port on the front baffle, these speaker cabinets are raised off their base panels by about 30mm on four metal pillars. This allows the bass reflex port to radiate with less air velocity, meaning no tendency to “chuffing” or rattling of the grille cloth. The downward facing bass reflex port is quite large. In fact, at 10cm in diameter, it is the largest bass port we have ever seen. The combination of the two very rugged but compact bass/midrange drivers and high performance with a well- designed crossover network makes for a highly rated speaker system which will give very satisfying performance in a stereo setup or as part of a great home theatre sound system when combined with other speakers in the Delta range. Power handling is quoted as 200 watts and this relates to normal music signals from a 200W per channel stereo amplifier. Combined with a sensitivity of 93dB/1W/1m, this means that these speakers can deliver very high sound levels. In practice, it can be teamed with amplifiers from 40 watts per channel to deliver highly satisfactory performance in most rooms. Our listening tests confirmed the very wide response of the XL-02s and they have a slight prominence in the midrange which tends to give a little extra “presence” – good for voice and brass instruments. Bass is smooth and extended, although Delta Audio also recommend the use of their subwoofer to augment bass frequencies below 40Hz. Fig.2 shows two curves which demonstrate the high performance of the Delta XL-02 tower loudspeakers. At top Fig.2: this diagram shows both the on-axis frequency response for the Delta XL-02 speakers (top) and the overall impedance curve (lower). Note the very smooth response, without any major peaks or troughs. This photo shows the very large port in the base of the enclosure. At 100mm it is one of the largest ports you are ever likely to (not) see. It faces down onto the base and since it is so large and unrestricted, it will not be subject to chuffing or frequency-doubling effects. 82  Silicon Chip siliconchip.com.au This side view of the Morel MW168H midrange/woofer clearly shows the very large blue aluminium voice coil former. That and the rugged suspension assure very high power handling. The woofer itself might look a bit small but it is a standard 6-inch driver; we should not have used such a big hand to hold it! is on-axis frequency response from 20Hz to 20kHz. As can be seen, the overall response is very smooth from below 50Hz to 18kHz, with no apparent peaks or troughs within that range. This agrees substantially with listening tests although in practice, the bass response in typical rooms appears even more extended, to below 40Hz than in the published curve. This accords with the manufacturer’s claimed response of 38Hz to 18kHz within ±2dB, using one-third octave smoothing. The lower curve of Fig.2 is the speaker impedance and as can be seen, it exhibits the classic double peaks of a bass reflex enclosure. In this case though, the two peaks are quite modest and nor are there any dips which would cause some amplifiers to misbehave. Speaker kits The Delta XL-02 oozes “class” – even down to the deeprouted DELTA logo at the base. Also in this photo you can clearly see the slightly oversize base and the speaker stand-offs. These are not just for show – as explained in the text (and photographed at left) the oversize ports aim down from the speaker boxes with air movement allowed by the space between the bottom of the box and the base. siliconchip.com.au These XL-02 tower speakers are very easy to put together since no carpentry or soldering is required. Literally the only tools you will require are a hammer, Phillips screwdriver and an Allen key. The enclosures are supplied fully assembled (apart from the base plate and grille cloth frame. They are also lined with acoustic wadding and have the crossover inductor and port already installed. Virtually all you have to do is to install the speakers, grille cloth frame and base plate. The accompanying photos tell the story and you can probably comfortably assemble a pair of speakers in an evening. Delta Audio loudspeaker systems are available only from www.kitaudio.com Log on to find full details of all Delta Audio loudspeakers. November 2005  83 Constructing the Delta Audio XL-02 Tower Speakers 1 Check to ensure that all components are included, according to the parts list shown on page 84. You will also need the following tools: Phillips head screwdriver, Allen key, hammer, scissors and a 1.5V battery for speaker polarity checking. 4 Place the small end of the female socket into the holes on the front of the cabinet. Carefully tap the sockets into the holes with a hammer until the bottom is flush with the front face of the cabinet. Before placing the drivers, foam must be fitted to ensure that no air can escape around the drivers. Apply foam tape to the driver cut outs at the front of the cabinets, as close to the edge as possible. 3 Place all cables connected to the terminal plate into the cabinet, then secure terminal plate to the cabinet with the four small screws provided. 84  Silicon Chip Pull the driver cable out through the driver cutout. Push the spade lug on the cable with a line down the front onto the “+” speaker terminal and then attach the other wire to the “–” terminal of the same driver. Place the driver in the cutout and carefully push down on the driver edges until it is properly in place. Repeat this step with the second driver. 5 2 Pull wire through from the inductor inside the cabinet (it has already been installed at manufacture) through the terminal hole. Connect the male and female connectors to the input terminal plate. 7 8 Pull the tweeter cable out of the cabinet and once again, locate the cable end with a line down the front. Push its spade lug onto the “+” driver and then attach the other wire to the “–” terminal of the same tweeter. Place the tweeter in the cut out and carefully push down touching only the edges until the tweeter is properly in place. 6 When installing the foam for the tweeter, ensure that you place it on the inside of the cutout. 9 Screw in all three drivers with the provided screws. Be very cautious not to slip; at this stage the drivers are very fragile. siliconchip.com.au 10 Briefly touch a 1.5V battery across the input terminals while watching the driver cones. The drivers should move in the same direction. If the drivers move in opposite directions, the connection to one or more drivers has been reversed and will need to be corrected. Parts List – Delta Audio XL-02 Tower Speakers* 2 XL-02 Cabinets – with wadding 8 Steel stand offs 2 Bases 2 Crossovers (with attached terminal plates) 2 Grilles with male clips attached 8 Base mounting screws 2 Metres of foam tape 8 Grille clips – female 4 Drivers 2 Tweeters * These are the contents of the XL-02 Tower Speaker pack from KitAudio, who are licenced to sell Delta Audio products 13 11 Turn the cabinets upside down so that you are facing the base. Place the four steel stand-offs in the outer corners of the cabinet so that they surround the predrilled holes. 12 Turn the speakers up the other way, connect your amplifier, wind up the wick . . . and enjoy! Where from, how much: Locate the base onto the top of the steel stand offs so that it sits flush. The base has predrilled holes to allow for the steel standoffs to fit snuggly. Insert the four long screws through the holes and standoffs into the cabinet and tighten with an Allen key. siliconchip.com.au Delta XL-02 towers and other speakers in the Delta range are available exclusively from www.kitaudio.com Three options are available:   Fully assembled ...................................................$1999.00 pair    Kit with fully assembled cabinets...........................$1699.00 pair    Kit without cabinets...............................................$1199.00 pair November 2005  85 CIRCUIT NOTEBOOK Interesting circuit ideas which we have checked but not built and tested. Contributions from readers are welcome and will be paid for at standard rates. 1W LED driver circuit This circuit is designed to drive the 1W LEDs that are now commonly available. Their non-linear voltage to current relationship and variation in forward voltage with temperature necessitates the use of a 350mA, constant-current power source as provided by this supply. In many respects, the circuit operates like a conventional step-down (buck) switching regulator. Transis- tor Q1 is the switching element, while inductor L1, diode D1 and the 100mF capacitor at the output form the energy transfer and storage elements. The pass transistor (Q1) is switched by Q2, which together with the components in its base circuit, forms a simple oscillator. A 1nF capacitor provides the positive feedback necessary for oscillation. The output current is sensed by transistor Q3 and the two parallelled resistors in its base-emitter circuit. Nick Ba When the curis this m roni on rent reaches winner th’s about 350mA, Peak At of a las the voltage drop Instrum Test ent across the resistors exceeds the base-emitter forward voltage of transistor Q3 (about 0.6V), switching it on. Q3’s collector then pulls Q2’s base towards ground, switching it off, which in turn switches off the main pass transistor (Q1). The time constant of the 15kW resistor and 4.7nF capacitor connected to Q2’s base adds hysteresis to the loop, thus ensuring regulation of the set output current. The inductor was made from a small toroid salvaged from an old computer power supply and rewound with 75 turns of 0.25mm enamelled copper wire, giving an inductance of about 620mH. The output current level should be trimmed before connecting your 1W LED. To do this, wire a 10W 5W resistor across the output as a load and adjust the value of one or both of the resistors in the base-emitter circuit of Q3 to get 3.5V (maximum) across the load resistor. Nick Baroni Willetton, WA. Contribute And Choose Your Prize As you can see, we pay good money for each of the “Circuit Notebook” items published in SILICON CHIP. But now there are four more reasons to send in your circuit idea. Each month, the best contribution published will entitle the author to choose the prize: an LCR40 LCR meter, a DCA55 Semiconductor Component Analyser, an ESR60 Equivalent Series Resistance Analyser or an SCR100 Thyristor & Triac Analyser, 86  Silicon Chip with the compliments of Peak Electronic Design Ltd www.peakelec.co.uk So now you have even more reasons to send that brilliant circuit in. Send it to SILICON CHIP and you could be a winner. You can either email your idea to silchip<at>siliconchip.com.au or post it to PO Box 139, Collaroy, NSW 2097. siliconchip.com.au Simple cable tester Here is a simple RJ-45 cable tester that can be assembled in quick time. It is intended for use with patch cables or similar, where both ends of a cable can be brought together and plugged into RJ-45 sockets on the tester. A PICAXE micro drives four of the eight possible connections on one end of the cable, feeding the anodes of four LEDs at the other end. The cathodes of the LEDs are returned via the remaining four conductors, themselves is series with four more LEDs. By flashing the LEDs in sequence and at varying intervals, it’s therefore possible to visually determine not only continuity but also shorts between conductors. The accompanying program is selfexplanatory and easily modified to individual taste. Glenn Jordan, Conway, South Carolina, USA. ($40) Program Listing 'PICAXE-08M Cable Tester main: if pin3 = 1 then step1 goto main step1: high 0 pause 1000 low 0 pause 1000 'start test when switch pressed 'output 0 high 'for 1 sec. 'output 0 low 'for 1 sec. for b0 = 1 to 2 high 1 pause 500 low 1 pause 500 next b0 'output 1 high 'for 1/2 sec 'output 1 low 'for 1/2 sec 'loop twice for b1 = 1 to 3 high 2 pause 333 low 2 pause 333 next b1 'output 2 high 'for 1/3 sec 'output 2 low 'for 1/3 sec 'loop 3 times for b2 = 1 to 4 high 4 pause 250 low 4 pause 250 next b2 'output 4 high 'for 1/4 sec 'output 4 low 'for 1/4 sec 'loop 4 times pause 250 if pin3 = 0 then step1 'leave off for 1/4 sec 'run tests again unless switch pressed step2: if pin3 = 1 then step2 pause 100 goto main 'wait until switch released 'short delay Issues Getting Dog-Eared? REAL VALUE AT $12.95 PLUS P & P Keep your copies safe with these handy binders. Available Aust, only. Price: $A12.95 plus $7 p&p per order (includes GST). Just fill in and mail the handy order form in this issue; or fax (02) 9979 6503; or ring (02) 9979 5644 and quote your credit card number. siliconchip.com.au November 2005  87 Circuit Notebook – Continued Improved LED torch The Novel LED Torch circuit presented in the February 2005 instalment of Circuit Notebook is an interesting approach for a variable intensity LED torch and can be improved upon with a few small modifications. The shortcomings of the initial design were the necessity of a separate power switch and the increase in intensity by only one LED at a time at higher illumination levels. The accompanying circuit addresses both of these issues. A double-pole, 6-way rotary switch is used as both a power switch and a 5-step intensity selector. The values of the resistors in the divider string were chosen so that 1, 2, 4, 6 or 10 LEDs are illuminated simultaneously when positions 1 to 5 of the switch are selected, with position 6 being “off”. Of course, the values of resistors in the chain may be altered to change the number of illuminated LEDs at switch positions 2 and up. Keep the total resistance as close to 100kW as possible. Load sharing multiple supplies A recent correspondent (“Ask Silicon Chip”, March 2005) asked about the possibility of running multiple laptop power supplies in parallel to increase load handling. This simple circuit shows how it can be done. As shown, the circuit will allow four laptop power supplies to be connected in parallel, each supply sharing a portion of the total load current. The nominal output is 13.8V, suitable for powering audio or radio gear. More supplies could be added just by adding more parallel branches to the circuit. The circuit is a variation on an arrangement often used for paralleling power transistors. The 0.1W emitter 88  Silicon Chip Other changes to the circuit include the use of the reference voltage output (pin 7) to power the voltage divider and the 100W resistor, so ensuring consistent behaviour with varying input voltage. An old torch housing or even a resistors help the transistors share the load more evenly. By splitting the transistor collectors (these are usually connected together), each transistor can be fed from a different supply. Supply 1 will carry a slightly higher load (up to about 5%), depending on the gain of the pass transistors. Emitter resistor values can be adjusted to compensate for variations in the rated maximum loads of the supplies. For example, if one supply can provide twice the current of its counterparts, its associated emitter resistor would need to be halved (or all others doubled). Load sharing will be improved if the transistor specifications are closely matched but in practice, this would be difficult to achieve unless you have access to quantities simple plastic tube could be used to house the circuit assembly and its three AA (or larger) cells, with the rotary switch positioned at one end. Col Hodgson, Wyoming, NSW. ($30) of transistors for comparison. The regulation of this simple design is not great. Expect around 14.5V at no load, dropping to a bit over 12V at full load. Supply 1 will need a minimum output of 17V, whereas the others will need a minimum of 16V. The output fuse needs to be rated for the total load. Each pass transistor should carry no more than 7A and all devices must be mounted on a large, common heatsink. Attach the 7815 regulator to the middle of the same heatsink to afford a measure of thermal overload protection. Diodes D1 & D2 are included for polarity protection and are required only if the supply is used for battery charging. Kelvin Lawrence, via email. ($40) siliconchip.com.au Paraphase tone control Here’s a tone control circuit for audio applications. It incorporates passive low and high-pass filters and uses only three transistors. The first transistor (Q1) amplifies the audio signal before it is AC-coupled to the second stage based on Q2. This second stage uses a high-linearity 2SC945 transistor and acts as a driver and phase split- ter. Its collector feeds a high-pass RC filter network, while its emitter feeds a low-pass RC network. After traversing the filter networks, the two signals are summed at the gate of Q3. The result is that some frequencies are attenuated while others are amplified, depending on their amplitude (adjustable by VR1 & VR2) and phase difference. Using the values shown, the crossover point of the two filters is approximately 1kHz. An N-channel JFET was chosen for Q3 due to its high input impedance. The JFET is available as part number 2SK30ATM (stock no. 317-5983) from RS Components at www.rsaustralia.com or phone 1300 656 636. The 2SC945 is available from Wiltronics Research, on the web at www.wiltronics.com.au or phone 1800 067 674. F. Winkler, Bunbury, WA. ($40) Silicon Chip Binders REAL VALUE AT $12.95 PLUS P & P H SILICON CHIP logo on spine & cover H Buy five and get them postage free! Price: $A12.95 plus $A7.00 p&p per order. Available only in Australia. Fig.1: the circuit uses four parallel power transistors (Q1-Q4) – one for each supply – plus a 15V 3-terminal regulator (REG1) to set the base voltages. The output is about 14.5V at no load, dropping to about 12V at full load. siliconchip.com.au Just fill in the handy order form in this issue; or fax (02) 9979 6503; or ring (02) 9979 5644 & quote your credit card number. November 2005  89 By Clive Seager* In Part 4, we used our Schools Experimenter board to control DC motors, solenoids and servos. In this, the final instalment of the series, we look at adding infrared remote control and voice recording capabilities. For more advanced experimenters, we also show how to build a sound detection circuit that complements the simpler light and temperature circuits described in Parts 2 & 3. IN THIS ARTICLE you will learn: • how to use infrared remote control; • how to record and play back sounds; • how to detect and respond to sounds. Many indoor projects lend themselves well to infrared remote control, so for the first project, we’ll show you how to add an infrared receiver to your board that will work with a TV-style remote control. We’ll then add an external voice recorder module and * About the author: Clive Seager is the Technical Director of Revolution Education Ltd, the developers of the PICAXE system. 90  Silicon Chip show you how to record and play back a sound clip via remote control. To get started, let’s look at the infrared remote control side of things. Infrared remote control Every infrared remote system consists of two parts: a transmitter and a receiver. There are many different protocols for sending infrared data, with most major manufacturers opting for their own “standard”. The PICAXE system uses the Sony infrared remote control (SIRCS) protocol, allowing it to be used with a normal TV-style remote control. All universal, “one-for-all” style infrared remote controls can be set up to control Sony brand equipment and therefore will work with this project. It’s just a matter of programming the remote with one of the Sony equipment codes provided in the accompanying instructions. For example, the TVR010 remote control featured here must be programmed with the unique code C-2-1-2. Note that it’s also possible to make your own transmitter using a second PICAXE-08M chip, instead of buying a universal remote. Check the “PICAXE Infrared Remote Control” article (featuring “Rudolph the Red-Nosed Reindeer”) in the November 2004 edition of SILICON CHIP for more details. The PICAXE-08M requires only four siliconchip.com.au additional components to receive infrared transmissions, as shown in the simplified circuit of Fig.1. This circuit (minus the PICAXE chip) is easily constructed on a breadboard and then connected to the experimenter board, as illustrated in Fig.2. Make sure that the DIL switch (SW2) positions 3 & 4 are OFF and that 1 & 2 are ON. Each infrared transmission is 12 bits long and is produced by modulating a 38kHz carrier signal (see Fig.3). A TSOP4838 infrared receiver module detects the infrared signal with the use of a photodiode. The signal is then demodulated (ie, the carrier is removed), before it is fed into the PICAXE-08M chip for decoding. A block diagram of the internals of the TSOP4838 receiver module is shown in Fig.4. The BASIC program in Listing 1 shows how to use the infrain2 command to read data from the infrared receiver module. Once an infrared transmission is received, the program uses familiar commands to switch one of the three LEDs on the experimenter board on or off, depending on which of the first six numeric keys on the remote control is pressed. Note that within the Sony protocol, the number transmitted by the remote control is actually one less than the number you would expect from the button (eg, pressing button 4 actually transmits the data value 3!). Task – write a program that makes the green LED flash to indicate the number of the numeric key pressed (ie, five flashes for key number five). Keys other than 1-9 should be ignored. Fig.1: this simple circuit adds infrared support to the PICAXE-08M. A Vishay TSOP4838 infrared receiver module detects and demodulates the infrared data stream, which is then fed into the microcontroller on input 3. Fig.2: here’s how to wire up the infrared receiver circuit on the breadboard and connect it to the School’s Experimenter. Recording & replaying sounds A significant number of functions are required to record and play back sound on a computer system. First, the sound must be picked up by a microphone and amplified. It must then be filtered and converted from analog to digital form. It can then be stored in memory ready for playback. To play back the sound, it must be retrieved from memory, converted from digital to analog format, amplified and then fed to a loudspeaker. This simplified description holds true for all digital sound recording systems and one of the key requirements for such a system is lots of memory space. Even short sound clips require a lot more memory than is available in a low-cost microcontroller like the PICAXE-08M. siliconchip.com.au Here’s what the above circuit looks like assembled onto the breadboard. Also shown is the TVR010 infrared remote control mentioned in the text. November 2005  91 Fig.3: basics of the SIRCS protocol, showing the composition of each serial transmission. A logic “1” is represented by a 1.2ms burst of the 38kHz carrier, whereas a logic “0” is represented by a shorter 0.6ms burst. Each bit is separated by a gap of 0.6ms. Fig.4: this diagram reveals the basic functional blocks inside the TSOP4838 infrared receiver. As well as the actual PIN (photo) diode, it includes amplifier, discrimination and demodulation circuits to reconstruct the original digital data, which appears on the “OUT” pin. One way of providing sound recording capabilities on a simple microcontroller-based system is to use a dedicated recording chip with inbuilt memory, such as one of the ISD5100 series Chipcorders (www.isd.com). These devices can store from 2-16 minutes of voice-quality sound. Unfortunately, these chips are quite difficult to interface to the PICAXE-08M. A much simpler and cheaper solution is to “hack” into a pre-assembled recorder module. These are available in many forms, from keyring note-takers to surplus modules originally destined for children’s toys. Generally, these modules are easily modified to work with PICAXE microcontrollers. One such module is shown in one of the photos. It is supplied with two pushbutton switches (record and play), a speaker, a LED and a battery holder, all attached to a small PC board via flying leads. The following description deals exclusively with the PPM155 module but other types are readily interfaced to the PICAXE micro in a similar manner. For example, the Oatley VRM1 25s voice recorder (www.oatleye. com) would probably be suitable, as would the 45-Second Voice Recorder project described in SILICON CHIP, in May 2005. Note: although designed for 4-cell (6V) operation, the PPM155 module described here operates satisfactorily from a 4.5V supply, as will most other 6V modules. Of course, we cannot guarantee that all modules will work from a 4.5V supply, so check for suitability before “hacking”! In some cases, a separate supply may be required for the module. Before going any further, install batteries in the recorder’s holder and try it out to make sure that it works properly. This will also give you the opportunity to discover how it works – before hacking it! You will note that with this module, the “record” switch has to be held down to record, while the “play” switch only has to be pressed momentarily to play back the sound. The LED should light while recording is taking place. Hacking the recorder module The first ‘‘hack” involves cutting off the battery holder so that the whole project can use the Schools Experimenter battery pack. Cut the red and black wires close to the battery holder, leaving plenty of length from the PC board side for connection to our project. The second job is to replace the “play” and “record” switches with outputs from the PICAXE-08M chip. Each switch is connected to the module via two red wires; one goes to “0V” and the other to the input of the speech memory chip. You need to identify which of the two wires goes to the speech memory chip and connect it to output 1 (for the “play” switch) or Fig.5: here’s how to connect the voice recorder module. If you’ve already constructed the infrared receiver on your breadboard, then don’t disassemble it – just add this circuitry as well. Note that you’ll need to solder short single-strand jumper wires to the end of each of the recorder’s flying leads so that you can plug them into the small holes in the breadboard. 92  Silicon Chip siliconchip.com.au The sound recorder module offered by MicroZed may differ from the unit shown here but should be just as easy to interface to the PICAXE micro. This unit features “record” and “play” buttons, a LED, a miniature speaker and a battery holder, all attached by short lengths of wire. All functions are performed by a single IC, which is hidden beneath a mound of black epoxy. Strangely, even the through-hole components are mounted on the copper side of the board! output 2 (for the “record” switch) of the PICAXE. The correct wire is easily identified by using your multimeter to measure the resistance between the negative (black) battery lead and the two wires soldered to the switch assembly. The “0V” wire will measure zero ohms to battery negative, so it can be ignored; the other wire is the one to be connected to the PICAXE. Your completed breadboard layout should look something like Fig.5. As you can see, we’ve added 330W resistors between the two PICAXE outputs and the module’s switch inputs, which help to protect against accidental wiring mistakes! Make sure that DIL switch (SW2) contacts 1 & 2 on the experimenter board are now switched off. The program in Listing 2 will record 10 seconds of sound and then immediately play it back. The playback is then constantly repeated, with a 1-second delay between loops. It is important to note how the outputs work; the module switches are “active low” and so we have to switch the PICAXE outputs high at the start of the program and then pulse them low to activate the module. The final step in the project is to combine the infrared circuit with the siliconchip.com.au sound recorder circuit. Task – write a program so that the record and playback features are triggered by a key press on the infrared remote control. If you combine this project with a servo-operated “puppet” on output 4 (see Pt.4 of this series for servo information), you could build a very interesting animatronics project! Sound detection In previous articles, we looked at how to measure light (using a lightdependent resistor) and temperature (using a DS18B20 sensor). Unfortunately, sound is not as easy to detect with a PICAXE-08M chip, as it requires considerably more than a simple “single component” solution. The main problems to be considered when designing a simple sound detection circuit are as follows: (1) While electret microphone inserts are ideal due to their low cost, they produce a very small signal that requires amplification; (2) The background noise level can vary considerably and so some form of calibration is required; and (3) Some noises, such as a hand-clap, are very quick and so could easily be missed by PICAXE programs. Fortunately, these problems can all be overcome at low cost, using an Par t s Lis t IR receiver & sound recorder 1 TSOP4838 infrared receiver module 1 TVR010 remote control (or any universal remote, see text) 1 PPM155 20s sound recorder (or similar, see text) 1 4.7mF 16V electrolytic capacitor 1 4.7kW 0.25W 5% resistor 3 330W 0.25W 5% resistors Note: the remote control (part no. TVR010) and TSOP4838 sensor (part no. LED020) are available individually or in a combination pack (part no. AXE040) from MicroZed, see www.picaxe.com. au for more information or phone (02) 4351 0886. Microzed can also supply the PPM155 sound recorder module. Sound detector 2 BC548 transistors (Q1 & Q3) 1 BC558 transistor (Q2) 1 1N4148 diode (D1) 1 electret microphone Capacitors 3 470nF polyester 1 1nF polyester Resistors (0.25W, 5%) 1 220kW 2 4.7kW 1 100kW 1 100W 1 10kW 1 5kW miniature trimpot (VR1) 1 50kW miniature trimpot (VR2) November 2005  93 Fig.6: the sound detection circuit uses a handful of low-cost parts. The first stage amplifies the signal from the microphone, which is then clipped, peak detected and finally buffered to provide a 0-3V output. electret microphone together with three common transistors and a few resistors and capacitors, as shown in Fig.6. This circuit will produce an analog output signal of 0-3V that can be read by the analog input (eg, input 4) of the PICAXE-08M. It also includes a time-delay feature that extends the period of the loudest signal. The program in Listing 3 demonstrates how to use the readadc command to read the signal from the detection circuit connected to input 4 and light the red LED when a loud sound is heard. Note that contact 4 of the DIP switch (SW2) must be in the “off” position. As before, the circuit can be constructed on your breadboard, using Fig.7 as a guide. We’ve used multi-turn trimpots for VR1 & VR2, as they’re easy to insert in the breadboard. However, ordinary single-turn miniature trimpots could also be used. Important: never force over-sized component leads into the breadboard holes. Solder short lengths of singlestrand jumper wire to large leads first to allow easy insertion. How the detector works Sound is sensed by a low-cost electret microphone, which for typical speech levels produces an output of about 1mV RMS at a distance of about 60cm. This means that we can expect signal levels of about 1-3mV from the microphone. The electret microphone is based on a special type of Field Effect Transistor (FET), physically constructed to convert vibrations (from sound or physical contact) into an electric signal. It is a polarised device and must be connected the right way around; the negative (-) lead is easily identified as it is connected to the external metal can. The output from the microphone is coupled to the base of the first transistor (Q1) via a 470nF capacitor. This transistor acts as an amplifier, providing a gain of 25 over the 300Hz-30kHz frequency range. The result is a larger (25-75mV) signal on the collector, where it is picked off by the wiper of sensitivity control pot VR1 to feed the following stage. Like the sound waves that it represents, the AC signal applied to the second stage consists of constantly rising and falling (alternating) voltage levels. In order to detect a signal (and therefore a sound) level above a set amplitude, it is necessary to establish a reference point on the signal from which to measure. To this end, the second-stage transistor (Q2) is biased to cut-off and amplifies only negative-going signals. The resultant positive-going signal at the collector causes D1 to conduct, thus charging the 470nF capacitor at its cathode to the peak signal level. The third transistor (Q3) is configured as an emitter follower. Its job is to buffer the signal from the 470nF capacitor, providing a low-impedance output for driving external circuitry. The signal at the output rises faster than it falls, proportional to the value of the 470nF capacitor at the base of Q3. We can therefore say that this capacitor defines the “delay time” that the highest sound level is present. Using the 470nF value shown, the Fig.7: the sound detection circuit calls for a much more complex breadboard layout than used previously and should prove a challenge! Make sure that you don’t mix up the two different transistor types and check their orientation – the flat side must face the right way around. Also, check that you have the banded (cathode) end of the diode pointing the right way. 94  Silicon Chip siliconchip.com.au decay time of the output signal is approximately 0.5 seconds. Increasing the capacitor to 2.2mF provides a decay time of approximately two seconds. Adjustments Initially, set the sensitivity control (VR1) to minimum (wiper towards the positive rail). Next, set your multimeter to read DCV and connect it between the output (emitter of Q3) and the 0V rail. Now adjust VR2 to a reading of just above 0V on your meter. This slightly positive bias of a few millivolts helps to avoid a “dead band” in the response of the detector. The sensitivity control (VR1) is now increased to a suitable level for the project. Typical speech at about 50cm from the microphone will give a DC output of about 1V peak. A handclap should produce an output of about 3V peak. As mentioned earlier, you’ll find that the signal is present for longer than the noise that causes it, as dictated by the value of the capacitor in the base circuit of Q3. And finally . . . We hope that this series of articles has given you some confidence in programming and working with PICAXE microcontrollers. Although this is the final in our “PICAXE in Schools” series, there will be more PICAXEbased projects in future issues. Happy SC experimenting! Program Listings Listing 1 Listing 2 main: infrain2 if infra = 0 then red_on if infra = 1 then yellow_on if infra = 2 then green_on if infra = 3 then red_off if infra = 4 then yellow_off if infra = 5 then green_off goto main init: high 1 high 2 record: low 2 pause 10000 high 2 play_back: low 1 pause 100 high 1 pause 10000 pause 1000 goto play_back red_on: high 0 goto main yellow_on: high 1 goto main green_on: high 2 goto main Listing 3 red_off: low 0 goto main main: readadc 4,b1 if b1 > 100 then bang goto main yellow_off: low 1 goto main bang: high 0 pause 1000 low 0 goto main green_off: low 2 goto main TAKE YOUR PIC Picaxe.com.au DISTRIBUTOR: MicroZed.com.au Developed for students, & professional performance makes PICAXE the most easy-to-use micro ever: PICAXE “programmer" is two resistors and a 4.5V battery! PHONE 1300 1300 735 735 420 420 8.30-4.30 AEST Mon-Fri FAX 1300 735 421 24 Hours ALL PICAXE ITEMS ON OUR SHELVES! STOCKISTS siliconchip.com.au In AUSTRALIA: altronics.com.au (Retail and Mail Order) oatleyelectronics.com School Electronic Supplies In NEW ZEALAND sicom.co.nz surplustronics.co.nz (School orders only – John - 03 8802 0628) November 2005  95 Salvage It! BY JULIAN EDGAR Scrounging and (gulp) buying the bits There are lots of ways to scrounge otherwise expensive parts for nothing or next to nothing. Here’s how to go about it. E ACH MONTH in this column, we describe how to use components salvaged from cheap and discarded goods – bits and pieces from printers, VCRs, electric typewriters, old computers, washing machines, coffee makers, cassette decks, speakers and other equipment. But where do you get these goods cheaply? It’s no good paying $40 for a VCR just to salvage one small DC electric motor – a motor that you could have bought for $10 brand new! However, at the other end of the spectrum, it’s well worth picking up an electric typewriter for $10 if it yields four stepper motors, a solenoid, heatsinks, rubber feet and springs, to name just some of the salvageable components. So how do you go about obtaining these potential treasure troves of bits? Garage sales The greatest difficulty with garage sales is also their greatest advantage – each is a lucky dip. So if you’re after a specific piece of equipment (say a high pressure coffee maker to get the silicone hose, temperature switch and solenoid), you could go to literally 50 garage sales and never see one. Alternatively, at the very first house, you could find that some “fruitcake” is selling five coffee makers at $10 for the lot! Unwanted consumer goods at garage sales can be really cheap. I recently bought two non-working VCRs (big, heavy, old and high quality) for $4 for the pair. Large portable sound systems – say a bit scratched and battered – can be picked up for five or ten dollars, while a box of obsolete computer parts – disc drives, cases, printers – could be labelled at $10. An old mobile phone complete with plugpack charger might cost you $2 and I have never been to a garage sale where the prices weren’t open to negotiation. Expect to get at least 30% off any marked price. Electronic repairers Companies that repair electronic or electrical goods throw out a huge number of broken appliances and other goods. Typically, a VCR or printer or dishwasher or stereo is taken in for a quote and then proves uneconomic to fix. Invariably, the owner doesn’t want it back and so it goes into the repairer’s rubbish output. If you approach a repair shop – especially a small repair shop – and tell them your name, what junk stuff you’d like and what you’ll be doing with the parts, you’re likely to get a favourable reception. Most electronic technicians hate having to throw out so much that is potentially still good for parts. However, they’re not going to go to any particular trouble for you (eg, putting stuff aside) if you never show up again, so it makes sense to call in frequently. This electric typewriter was bought by tender for $5. Inside you’ll find good quality stepper motors, metal rods and rollers, microswitches and a power switch. Buying by tender works well with outdated electrical items. 96  Silicon Chip Auctions Auctions can be wonderful places siliconchip.com.au Want cheap, really bright LEDs? We have the best value, brightest LEDs available in Australia! Check these out: Luxeon 1, 3 and 5 watt All colours available, with or without attached optics, as low as $10 each Low-cost 1 watt Like the Luxeons, but much lower cost. •Red, amber, green, blue and white: Just $6 each! Lumileds Superflux These are 7.6mm square and can be driven at up to 50mA continuously. •Red and amber: $2 each •Blue, green and cyan: $3 each Partly disassembled VCRs can be picked up from electronics repairers for nothing. The best bits inside are the fabulous quality bearings, hardened steel shaft and diecast alloy bearing supports of the video head. You’ll also find solenoids, microswitches, springs, belts and pulleys. to buy equipment. However, you need to find the right sort of auction – one that is relatively small and auctioning general or household lots. People getting rid of an old printer, an electric fan, or a “box lot” comprising a TV, clock radio, audio mixer and a computer game often have no reserve prices on the goods. That means the highest bidder takes it home. As an example, the box lot that I recently bought at an auction (which actually did consist of a small B&W portable TV, a brand new audio mixer, a brand new reverb unit, an old clock radio and two new hand-controllers for computer games) cost me just $12. And just a few weeks ago, I bought an electric pedestal fan (I wanted the plastic blade for a wind generator project) and a chair (that I didn’t want) for $2. An old electric typewriter – a very large and heavy one that yielded some really good parts – cost $5. Tender sales Tender sales of the sort that I am describing are held at tender centres – rather like huge secondhand stores. The goods are arranged for inspection and, as with an auction, each item has a “lot” number marked on it. However, unlike at an auction, when you make a bid (called a tender) you have no Asian Superflux Same as above, but much lower cost. •Red and amber: Just 50 cents each! •Blue, green, aqua and white: $1 each. Go to www.ata.org.au or call us on (03)9419 2440. Ozitronics www.ozitronics.com Tel: (03) 9434 3806 Fax: (03) 9011 6220 Email: sales2005<at>ozitronics.com K28 – Voice Activated FM Tx . . . . . . . . . . . $17.60 K32 – Two Stage FM Tx . . . . . . . . . . . . . . . . $15.40 K74 – PC Printer Port Relay Board . . . . . . $53.90 K74A – Assembled K74 . . . . . . . . . . . . . . . . . $70.40 K141 – Multi-Mode Timer . . . . . . . . . . . . . . . $32.45 K141A – Assembled K141 . . . . . . . . . . . . . . . . $48.95 K142 – 12 Channel IR Relay Board . . . . . . . $92.40 K146 – 40 Sec Message Recorder . . . . . . . . $30.80 K148 – 4-Digit Timing Module . . . . . . . . . . . $30.80 K153 – DTMF Tone Grabber . . . . . . . . . . . . . $40.15 K154 – 4-Digit Preset Down Counter . . . . . $32.45 K156 – Dual HI/LO Switched Relay . . . . . . . . $19.80 K173 / 5 – Serial / Parallel RF Tx . . . . . . . . . . . $52.80 K174 / 6 – Serial / Parallel RF Rx . . . . . . . . . . . . $60.50 Prices include GST – shipping extra. Full documentation available from website. Rat It Before You Chuck It! Whenever you throw away an old TV (or VCR or washing machine or dishwasher or printer) do you always think that surely there must be some good salvageable components inside? Well, this column is for you! (And it’s also for people without a lot of dough.) Each month we’ll use bits and pieces sourced from discards, sometimes in mini-projects and other times as an ideas smorgasbord. And you can contribute as well. If you have a use for specific parts which can siliconchip.com.au easily be salvaged from goods commonly being thrown away, we’d love to hear from you. Perhaps you use the pressure switch from a washing machine to control a pump. Or maybe you have a use for the highquality bearings from VCR heads. Or perhaps you’ve found how the guts of a cassette player can be easily turned into a metal detector. (Well, we made the last one up but you get the idea . . .) If you have some practical ideas, write in and tell us! November 2005  97 numbers). I got six of them – a 50% success rate! The tip Plastic storage containers are handy for storing all those scrounged parts but keep only the good bits. They take up little room and the original bulky stripped chassis can be discarded. idea of the amounts that other people are bidding for the same items. That’s because the tenders are submitted in writing. So how does it work? The goods can only be inspected on certain days – usually a Friday, Saturday and Sunday every fortnight. At the inspection, a clipboard is issued and you fill in your contact details on the form. Carrying the clipboard around with you, you then write down the “lot” numbers of the items that you’re interested in and state what you’re prepared to pay for them. Note that some items will have a reserve but you’re not told what it is. The following Monday, you hear which of your tenders were successful. A small processing fee is paid for each successful tender, together with the equivalent of a buyer’s premium – again around 10%. For the sorts of goods being described here, tender centre sales work brilliantly. That’s because there’s no auctioneer jacking up the starting price and very often on old electrical goods, yours is the only tender that will submitted. As a guide, I recently tendered $5 each on 12 items that included electric typewriters, computer printers and photocopiers (all were different lot If you’re lucky enough to live near to a rubbish tip that either allows you to take stuff at will or sells salvaged goods for only a nominal fee, you’re laughing. This is by far the best way of getting the widest variety of goods at the lowest cost. Unbelievably, many goods to be found at the tip are in full working order. Included are washing machines, dishwashers, VCRs, portable stereos, plugpacks, PCs, monitors, TVs and clocks – in fact, any electrical consumer item that you can think of. But it gets even better. At larger tips, you’ll also find a range of industrial discards. Generally, these are not in full working order but it’s still common to find large heat exchangers, fans, pumps and so on. Finally, what were once very expensive commercial and industrial goods can also be found. In this category are photocopiers, film processors and laboratory equipment. Depending on the set-up, you can either salvage the good bits and pay for just those items, or you can take the whole item and salvage the wanted bits at your leisure. It’s easy and fun Buying old electronics goods, stripping them for useful bits and then getting rid of the rest is easy, effective and good fun. You’ll learn a little about how things work, you’ll get some good components to build interesting projects and you’ll also be doing your bit for recycling. SC The Latest From SILICON CHIP Completely NEW projects – the result of two years research & development • • • • 160 PAGES 23 CHAPTE RS From the publishers of Learn how engine management systems work Build projects to control nitrous, fuel injection and turbo boost systems Switch devices on and off on the basis of signal frequency, temperature and voltage Build test instruments to check fuel injector duty cycle, fuel mixture and brake and coolant temperatures Mail order prices: Aust. $A22.50 (incl. GST & P&P); Overseas $A26.00 via airmail. Order by phoning (02) 9979 5644 & quoting your credit card number; or fax the details to (02) 9979 6503; or mail your order with cheque or credit card details to Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. 98  Silicon Chip Intelligent turbo timer I SBN 095852294 - 4 9 780958 522946 $19.80 (inc GST) NZ $22.00 (inc GST) TURBO BOOST & nitrous fuel controllers How engine management works siliconchip.com.au PRODUCT SHOWCASE Panel-mount dual bargraph display Sub $5, single chip digital TV tuner Amalgamated Instrument Co Pty Ltd believe they have filled a longvacant niche in process control instrumentation with their new PM4-IV2 panel-mount monitor, a dual-bargraph display in a 1/8 DIN panel mount enclosure. A bargraph display is ideal where a quick visual check of data is required and a dual bargraph can convey a wealth of information and comparison data quickly and intuitively. Each of the two 32-segment bargraphs can be independently scaled and the display can be configured to show a solid bar or a single segment point. Features of the PM4-IV2 include: • Bright 32-segment red LED bars. • User-selectable inputs of 4-20mA, 0-2VDC or 20VDC. • 1kV isolation between input and input and between power supply and inputs. • Scaling setup using pushbuttons on rear of display and a mA or DCV source. US-based RF Magic has worked some magic to produce what they claim is the world’s most advanced digital TV tuner IC – at a price of less than $US5 in small quantities. Announcing their RF4000 DVB-T silicon tuner for digital terrestrial television applications, the company said that it would comply with the international DVB-T standard popular in Europe, Asia, Australia and South Africa. Employing RF Magic’s RF Systems “on a Chip” technology, the RF4000 contains all front-end functions and requires no external SAW filters or amplifiers. In addition, the AdaptiveTune feature allows key characteristics of the tuner to be programmed via software to optimise front-end performance for different environmental conditions. The compact, highly integrated IC simplifies customer’s RF system design and enables sleeker, more stylish receiver designs with a footprint one-quarter the size of comparable discrete tuners. • 240VAC, 110VAC, 24VAC or 12 48VDC power supplies available, with others on request. Applications could include monitoring levels in tanks to compare contents, monitoring and comparing engine outputs for throttle adjustment, etc, flow into and out of a tank or system, actual vs theoretical targets and many more. Contact: Amalgamated Instrument Coy Box 8350, Perth Business Centre 6849 Tel: (02) 9476 2244 Fax: (02) 9476 2902 Website: www.aicpl.com.au Elexol’s new “Ethernet” I/O Module 24 The Ether I/O 24 is an UDP/IP controlled digital Input/Output module. The module features three 8-bit ports with 5V level signal lines. Each of the 24 lines can be independently programmed as either an input or output. The 72 x 72 x 28mm module connects to any Ethernet network supporting the TCP/IP protocol suite and can communicate with any point on that network. By connection with an Internet router, the device can communicate with any Internet connected device. An on-board EEPROM allows all ports to power up in a user-programmable state. The module’s output pins are able to source or sink up to 30mA to allow for direct connection to a variety of devices. Optional boards connect to siliconchip.com.au the module to provide relay outputs, isolated inputs, switches or screw terminals to provide for the easy connection of external sensors, switches or other devices. Applications include home and industrial automation, digital input and output from any networked PC, remote data acquisition or alarm monitoring (by network or internet), PC-controlled machines and distributed machine I/O and remote lighting/power control and/or monitoring. Contact: Elexol PO Box 5972, GCMC, Qld 9726. Tel: (07) 5574 3833 Fax: (07) 5574 3899 Website: www.jaycar.com.au Contact: RF Magic 10182 Telesis Court, San Diego, CA 92121 Tel: +1 858 546-2401 Fax: +1 858 546-2402 Website: www.rfmagic.com AUDIO MODULES broadcast quality Manufactured in Australia Harbuch Electronics Pty Ltd 9/40 Leighton Pl. HORNSBY 2077 Ph (02) 9476-5854 Fx (02) 9476-3231 November 2005  99 ATX Supply Tester How many times have you come across a dead PC and not known whether the fault was with the power supply itself or another fault was preventing the supply from starting? Here’s a neat solution from Microgram – an ATX supply tester which allows quick and easy testing of any ATX supply. If you’re involved in selling or servicing PCs, this little device could be worth its weight in gold! It’s priced at $49.00 (Cat No 813113). Contact: Microgram Computers 1/14 Bon Mace Close, Berkeley Vale, NSW 2261 Tel: (02) 4389 8444 Freefax: 1800 625 777 Website: www.mgram.com.au Colour touchscreen application kit The Color Touchscreen Application Kit from Rabbit Semiconductor, Inc gives integrators the ability to add a color touch screen to their embedded systems. The color touchscreen, with its numerous customisable features, enhances Rabbit-based systems by providing an intuitive user interface, modern display controls and increased functionality. The graphical user interface can be customised using standard desktop tools. The application kit includes a Reach Technology SLCD controller board, a 5.7” TFT Hitachi colour display, Dynamic C development software and a RCM3720 Ethernet RabbitCore. The application kit also includes a NEMA 4 enclosure that allows for rugged, waterproof installation. The SLCD controller allows an LCD graphic display to be accessed as an intelligent serial device. User-defined bitmaps via standard desktop tools provide a modern-looking interface and include tabbed document inter- face pages and many different types of controls, such as radio buttons and check boxes. The touch interface enables buttons to be defined on screen which return a serial string when pushed. Contact: Dominion Electronics Unit 13, 82 Reserve Rd, Artarmon NSW 2064 Tel: (02) 9906 6988 Website: www.dominion.net.au SanDisk introduces U3 Webcam with sound as well Want to stay connected with families and friends – with both vision AND sound? This easy-to-use “Connectland” high resolution webcam featuring a built-in microphone is an economic way to do it. It has 330K pixels (640 x 480 VGA) resolution, along with 1024 x 768 video capture resolution. It comes complete with VP-EYE v4.0 application software and a USB 1.1 typeContact: A-to-mini-USB cable. Peridyme Size is 61 x 65 x 60mm and it Unit 20/191 Parramatta Rd Auburn 2144 weighs just 60g. Tel: (02) 9737 8809 Fax: (02) 9737 8807 It comes from Peridyme and is Website: www.peridyme.com.au priced at $72.60 inc GST. The first USB smart drives, using U3 technology, are now available. U3 is a powerful new platform that enables users to store and manage their “personal workspace” – including files, programs, passwords and settings – on a tiny device the size of a pack of gum. Contact: SanDisk Corporation 140 Caspian Ct, Sunnyvale, CA USA 94089 Tel: 00111 408 5420500 Website: www.sandisk.com SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK We supply Radiometrix VHF & UHF OEM radioSC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SCfor WEBLINK WEBLINK SCcontrol WEBLINK SC WEBLINK SC WEBLINK SCwith WEBLINK modules wirelessSCdata comms, andSC WEBLINK Our website is updated daily, over SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK monitoring. We also stock low cost easy to 5,500SCproducts through our SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK WEBLINK available SC WEBLINK SC WEBLINK use Bluetooth modules and the new rfBASIC SC WEBLINKsecure SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SCordering WEBLINK facility. 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Contact Phil Benedictus or Lawrence Smith on (02) 9211 9792 for all the details! 100  S C RF Modules Australia JAYCAR JAYCAR ELECTRONICS ELECTRONICS WebLINK: www.rfmodules.com.au WebLINK: WebLINK: www.jaycar.com.au www.jaycar.com.au siliconchip.com.au SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC Broadband (20-1000MHz) RF amplifier The new Ophir 5303039D broadband A/AB linear amplifier has exceptionally low noise power (kTB) and a frequency range of 20 to 1000MHz, making it ideally suited to wide-band communications requiring receive/ transmit functions in CW/AM/FM/ PM and pulse modes. The amplifier can be switched within 2ms to be at 20dB of kTB, making it suitable for electronic warfare applications. The amplifier has a saturated output of typically 50W and can withstand input power of +20dBm. Another feature is excellent harmonic performance, having harmonics contributions of less then -20dBc at a power output of 30W. Small signal gain exceeds +25dB and small signal response flatness is ±2.0dB max. Spurious signal contribution is less than -60dBc at a power out- Cleverscope CS328 USB Oscilloscope put of 30W. The amplifier is supplied as a module suitable for cold-plate mounting and requiring only a single 28V DC power supply. Contact: Westek Electronics Pty Ltd U2, 6-10 Maria St, Laverton Nth 3026 Tel: (03) 9369 8802 Fax: (03) 9369 8006 Website: www.westek.com.au No ring ring means no ring-ing No Ring Ring is the apt name for a new range of vibration damping rings for valves. Simon Brown from Design Build Listen explains that all valves suffer from some level of microphony. Preamplifier valves in particular may benefit from some form of vibration damping, leading to noticeable improvements in sound quality. No Ring Rings are made of a elastomeric material that is rated to 220°C so that it will continue its job for the life of the valve – despite the fact that valves get hot. No Ring Ring are available in three sizes to suit common valves. Contact: Design Build Listen The Cleverscope CS328 from Grantronics is a mixed-signal digital storage oscilloscope that connects to your PC’s USB port. It has two analog channels with 100MHz bandwidth, sampled at up to 100MSa/s (each channel) at 10-bit resolution and can store up to 4M samples per channel. It also has an external trigger input and eight digital inputs. Analog input signals can be displayed in oscilloscope (normal and zoomed) and spectrum analyser modes – all simultaneously. Digital inputs can also be displayed at the same time. A 0.2Hz–10MHz signal generator option is available, which can output sine, triangle (1MHz max) and square waves, with sweep capability. The CS328 is supplied with two 150MHz oscilloscope probe kits, probe kits for the eight digital inputs, a universal power supply, user manual and software on a CD. List price is $1495+GST. For this month only, you can get a CS328 for only $1450+GST. Full specifications and screen shots are available from the Grantronics web site. Contact: PO Box 5415, Dunedin, 9001, New Zealand. Fax +64-3-4773817 Website: www.designbuildlisten.com Grantronics Pty Ltd PO Box 275, Wentworthville NSW 2145. Tel: (02) 9896 7150 Fax: (02) 9896 7153 Website: www.grantronics.com.au C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SCTV WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK International satellite reception in JED designs and manufactures range SC WEBLINK We specialise in providing a range of SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SCaWEBLINK SC WEBLINK SC WEBLINK SC WEBLINK home now affordable. 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C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK Tel:(02) 9939 4376 Tel:(02) 9939 4377 Fax: (02) C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK WEBLINK WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK Tel: (03) SC 9762 3588 SCFax: (03) 9762 5499 SC WEBLINK Tel:(07)SC 4934 0413 SC Fax: (07) 4934 0311 SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK WEBLINK WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK ovember C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK C WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK SC WEBLINK Av-COMM Pty Ltd WebLINK: avcomm.com.au WebLINK: avcomm.com.au siliconchip.com.au Jed Microprocessors Pty Ltd TeleLink Communications WebLINK: jedmicro.com.au WebLINK: telelink.com.au N 2005  101 SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC Vintage Radio By RODNEY CHAMPNESS, VK3UG Vintage radio clubs: 15 years old and still going strong Vintage radio clubs have played a vital role in preserving Australia’s radio heritage. Two very active clubs are the Vintage Radio Club of North East Victoria and the HRSA NSW North Coast Group, both of which have now been going for over 15 years. W HEN IT COMES to our radio heritage, the retention of records and working equipment has, until relatively recently, been rather spasmodic. Many people in the past considered old and/or obsolete equipment as only suitable for the rubbish tip. Unfortunately, this “throw-it-away” attitude has robbed Australia of much extremely interesting information on our vintage radio heritage. As a result, some enthusiasts have now realised that this information and the equipment is worth saving and restoring. For example, on a personal basis, I wanted to know about the history and development of communications in outback Australia. Both the equipment used in the early days and any associated information was disappearing quickly, so it proved quite a challenge. Fortunately, I was able to obtain help from several people, which enabled me to trace this history with reasonable accuracy. My efforts proved to be very timely, as two of the people who gave me considerable help have since died, while the remainder are quite elderly. The results of my research appeared in a book entitled “Outback Radio – from Flynn to Satellites”, which was reviewed in the January 2005 issue of SILICON CHIP. Unfortunately, the same attitude of “get rid of the old” has been quite evident when it comes to commercial and domestic radio equipment. However, there were a few individuals who did realise the importance of this gear and began collecting over 30 years ago – well before there were any clubs or groups formed by like-minded people. In my own case, for example, I half-heartedly began collecting WWII military equipment around 1970 and my interest in vintage radio receivers grew from there. Radio clubs One end of the table . . . a collection of sets, test instruments and publications from a recent display put on by the Vintage Radio Club of NE Victoria. 102  Silicon Chip The idea for an association to band together radio collectors and restorers in Australia came from the late Len Davenport in Alice Springs. However, Len was not in the position to personally start such a group due to his remote location, so Ray Kelly in Melbourne, with help from other likeminded people, started the Historical Radio Society of Australia (HRSA) in April 1982. It subsequently proved siliconchip.com.au The other end of the table . . . more sets, test instruments and publications from the Vintage Radio Club of NE Victoria. very successful – it is so much easier in a club environment, for example, to obtain information, parts and advice for all sorts of projects. The Historical Radio Society of Australia now boasts a membership of around 1100. And across the Tasman, the New Zealand Vintage Radio Society Inc. has a solid membership of about 350. Other groups have also since sprung up with the same general interests. In 2004, two of these groups celebrated their 15th year of operation: (1) the Vintage Radio Club of North East Victoria Inc. (centred around Shepparton and Benalla); and (2) the Historical Radio Society of Australia NSW North Coast Group, which is centred around Coffs Harbour. Vintage radio club The Vintage Radio Club of North East Victoria was convened in Wangaratta in April 1989. Its first president was Bob Young and its aims were to promote the collection and restoration of radio equipment and to explore the history of radio in general, particularly around the north-east area of Victoria. It currently has about 36 members, siliconchip.com.au with more than half this number regularly attending meetings. Every five years, the club holds an informal dinner to discuss previous activities. However when the 15th year celebrations came up, it was decided to hold a more formal gathering. Ken Austin, a local retired broadcaster, gave the club a very informative talk on his career in radio, starting from when he commenced in 1941 at the age of 17. It was a hard job during the war, with each person expected to do a lot of different things with very little assistance or money. Members also displayed a number of items relating to the various activities during the club’s existence. As shown in the photos, there were quite a number of receivers built for the annual “Hellier Award” (see below), with many fine examples of woodworking. Also on show was a rare Pyrox wire recorder, plus interesting advertising literature and books. competition to build or restore vintage radio equipment. By way of background, station 3WR initially operated from Les Hellier’s home in Wangaratta, Victoria for about nine months but was not a commercial success. It was subsequently reborn in January 1931 with twin antenna masts dominating the town from Osmotherley’s building, on the corner of Reid and Murphy Streets, and a proper studio established in Hellier’s Sports Store (also in Murphy street). 3WR ultimately became 3SR at Shepparton on 1260kHz. It’s interesting to note that, The Hellier Award Named after Les Hellier who established the first licensed country radio station (3WR) in Australia in 1925, the Hellier Award is an (almost) annual Ray Kelly helped found the Historical Radio Society of Australia back in April 1982. November 2005  103 A selection of Hellier Award entries and certificates from recent years (Vintage Radio Club of NE Victoria). during its life, 3WR/3SR appears to be the only station within Australia that has not changed frequency. Getting back to the award, the competition involves club members either building or restoring some piece of radio equipment, whether it be a test instrument or a receiver. The various entries and then judged and the award given out at the June meeting (see photos). It’s interesting to note that the club has members with a wide variety of skills. Some are very good at restoring timber cabinets, while others have excellent skills with bakelite cabinets. Plastic cabinets are a different story though and no-one claims any special expertise with these! Other member are quite good at collecting historical information and between them, a good library of technical and historical information is available. Invariably, quite a few members specialise in the technical side of vintage radio, having been employed in the radio field or electronics for most of their working lives. In fact, the club could not manage without those who have the skill to manufacture bits and pieces that are no longer available. Monthly newsletter Vintage receivers and replica vintage receivers from the Vintage Radio Club of NE Victoria’s 15th anniversary display. The club also has a monthly newsletter. Edited by Eric Irvine, it has been important for providing technical information and keeping members interested in the club’s activities. Indeed, much of the success of the club can be attributed to the newsletter. As part of its activities, the club also occasionally displays vintage equipment in conjunction with other groups and the local Benalla library has been the venue for several displays over the years. HRSA: NSW North Coast An ancient (and rare) Pyrox wire recorder (Vintage Radio Club of NE Victoria). 104  Silicon Chip Brian Lackie from Urunga has been involved with vintage radio for many years and was one of the founding members of the HRSA back in 1982. Subsequently, in October 1989, Brian and Ray Kelly convened a meeting with other enthusiasts, resulting in the formation of the North Coast Group of the HRSA. This group is smaller than the Victorian group, with around 23 members. However, it is very active and often has displays at various venues. Their main meetings are held every two siliconchip.com.au Photo Gallery: Mullard 40 VALVES AUDIO HI-FI AMATEUR RADIO GUITAR AMPS INDUSTRIAL VINTAGE RADIO We can supply your valve needs, including high voltage capacitors, Hammond transformers, chassis, sockets and valve books. WE BUY, SELL and TRADE SSAE DL size for CATALOGUE ELECTRONIC VALVE & TUBE COMPANY PO Box 487 Drysdale, Vic 3222 76 Bluff Rd, St Leonards, 3223 Tel: (03) 5257 2297; Fax: (03) 5257 1773 Email: evatco<at>pacific.net.au www.evatco.com.au Select your microcontroller kit and get started... From $295* Released under the Mullard name in 1938, this 4-valve set used an Airzonemanufactured chassis fitted to either a cream or brown Bakelite cabinet. The valve line-up was as follows: 6A7 frequency changer, 6F7 IF/audio amplifier/detector, 42 audio output and an 80 rectifier. Photo: Historical Radio Society of Australia, Inc. months and generally take the form of a social gathering, often with a barbecue lunch. As part of its activities, the group is quite active in mounting displays at agricultural shows, shopping centres, life-style shows, motor shows – in fact, anywhere the club believes that they can mount an interesting display. As a result of these displays, the group has gained members and has often been given some rather rare radio equipment and literature. It’s all part siliconchip.com.au of making sure our heritage doesn’t disappear. Communication is always important if any club is to remain active and it was decided to issue a newsletter every six months back in 1992. It now comes out around every three months. In addition to their normal meetings, they also have occasional technical meetings, to assist any member who has any problems with restoration projects. This is a valuable part of the group’s activities, as only a small num- RCM3400 Fax a copy of this ad and receive a 5% discount on your order! Feature rich, compiler, editor & debugger with royalty free TCP/IP stack • Prices exclude GST and delivery charges. Tel: + 61 2 9906 6988 Fax: + 61 2 9906 7145 www.dominion.net.au 4007 ber of members have comprehensive technical knowledge and/or cabinet restoration skills. Finally, there are several other clubs and groups scattered throughout Australia and New Zealand which cater for vintage radio buffs. In varying degrees, they provide mutual encouragement, assistance with restoration, access to bits and pieces, and collection of historical literature. It all helps preserve our vintage radio heritage. SC November 2005  105 ASK SILICON CHIP Got a technical problem? Can’t understand a piece of jargon or some technical principle? Drop us a line and we’ll answer your question. Write to: Ask Silicon Chip, PO Box 139, Collaroy Beach, NSW 2097; or send an email to silchip<at>siliconchip.com.au Servo drivers need supply bypassing I have built three servo driver circuits as described in the May 1994 issue and they work like a treat, when working by themselves. However, I then designed a PC board to accommodate all three circuits and when connected to servos, they are obviously all interfering with each other and the servos just jitter back and forth. What have I done wrong and how do I fix this problem? (A. M., via email). • You have not done anything wrong. As you say, each circuit works fine by itself. The problem is that each time one of the circuits delivers an output pulse, it pulls the supply down slightly and this then affects the timing of the pulses from the other two circuits – so they are all interfering with each other. One solution would be to operate each circuit from its own battery supply but that is not really practical. The next best thing is to separately bypass the supply to each servo driver circuit. This can be done by inserting a 100W resistor in the positive rail to each driver circuit and then connecting a 100mF capacitor across the supply rail to each driver. The 100mF capacitor is said to “bypass” interfering signals on the supply. Speaker protector for Studio 350 amplifier I am currently building several of your Studio 350 amplifiers (SILICON CHIP, January 2004) and I am incorporating the Loudspeaker Protector from the “Ultra-LD Amplifier” design. My problem is that feeding the speaker protector circuit from the 70V rails will cause the maximum differential voltage for the 317 regulator to be Shunt Regulator For Wind Generator Regarding the shunt regulator described in the June 2005 edition, I have purchased the kit from Oatley Electronics and am about to start building it but one major hurdle is in the way. Upon re-reading the details and the article, there is no reference to the connection of a wind generator or solar panel. The only external connections are the negative and the positive leads which the article states go to the battery. One would assume that the positive from the wind generator would go straight to the battery and the negative would do the switching but it’s not stated in any documentation. Sorry if I seem vague on this as I’m just starting on wind power for my shed. Also could I connect an 80W panel and a 250W wind generator to the shunt regulator as the 80W panel is currently being used 106  Silicon Chip to charge the batteries via a simple blocking diode. The batteries are heavy-duty deep-discharge NiFe types. (B. C., Nairne, SA). • The shunt regulator connects directly across the batteries, as indicated in the article. Basically, it diverts current away from the batteries and through the dummy load once the terminal voltage equals the preset value, thus preventing them from being overcharged. You’ll still need the diode in line with the solar panel output. Note also that you’re going to need a bigger dummy load than that shown in the article for use with a 250W generator. The idea is to match the power handling of the shunt to the output of your generator, so that at full output power, the dummy load is capable of dissipating all available energy. exceeded. I could increase the series dropping resistor, use a second preregulator or possibly enlist the aid of an appropriate zener but I thought you may have a more elegant solution. I am not using a fan so the current drawn will not be great. (M. C., via email). • The way to solve this is to use the same discrete regulator as used in the 500W loudspeaker protector (October 1997. This used a BD649 NPN transistor as the regulator, fed by a 13V 0.5W zener diode at its base. The zener was fed from a 2.7kW resistor, from collector to base. The transistor requires a substantial U-shaped heatsink. Finally, the whole protector circuit was run from the 57VAC supply via a diode, 270W resistor and 470mF 100V capacitor. You can do the same in your setup. How to re-transmit UHF/VHF TV signals I have been trying to find a solution to re-transmit TV signals from a known good source to a house in a valley that does not get signal at all. I want to set up a passive re-transmission systemwith two antennas on the hill and a receiving antenna at the house. I need a passive or active solution. If I have to make it myself I will. (R. F., via email). • We have not published anything on this topic but the general method would involve picking up the signal by a hillside antenna, amplify it in a masthead amplifier, feed it to another antenna pointing downhill and then pick it up at the bottom of the hill. 24V version of temperature switch I have recently purchased the Temperature Switch kit that was featured in your publication “Performance Electronics for Cars”. My problem is that my vehicles are 24V. I am trained in electronics so I propose to modify the circuit so that the siliconchip.com.au zener diode (ZD1) is changed to 12V 5W instead of 16V and the 100mF capacitor uprated to 63V instead of 16V. I also intend to install a 275W resistor in series with the relay coil. I would appreciate your comments on these changes. (B. M., via email). • You would probably be better off to change the 3-terminal regulator REG1 to an LM2940CT-5 and then remove zener diode ZD1 to prevent its high dissipation. You should also use a 1W 270W resistor in series with the relay coil. Fence controller does not zap I have built the electric fence controller in the April 1999 issue but I cannot get the high-tension side to work. After completing the construction, I have followed the test procedure and set the trimpot VR1 to 340V, with pin 6 of IC2b tied to pin 8 with a 10kW resistor. This was successful. After disconnecting the 10kW resistor, I cannot get any spark from the HT side of transformer T2. Can you give me some pointers as to what may be wrong? (K. O., via email). • There are two likely possibilities. The first may be that the windings of the transformer may be arcing over when it is fired. You should be able to hear this happening, if this is the case. Alternatively, the Triac may not be triggering. Check that the voltage at the emitter of transistor Q3 switches to 0V and 5V at around a 1-second rate. If not, check the circuit closely for faults around IC2b and Q3. Puzzlement with the Mesmeriser clock I recently purchased the Jaycar kit for the Mesmeriser clock described in the June 2005 issue. My question relates to “wire jumpers”. The kit did not contain any tinned copper wire (to be cut and used as jumpers) and the text makes no reference to jumpers in the article. Yet there remain a number of holes in the circuit board. Also the component overlay does not show any jumpers (usually indicated by black lines in past component overlays). I would appreciate it if you would advise me if jumpers are used or not. (K. J., via email). • There are no links to be installed. siliconchip.com.au Trip Computer For Diesel Vehicles It has been a long time since I have had the time to read an electronics magazine, so on a recent break away from the farm I purchased an issue of SILICON CHIP and enjoyed it very much. Your technical features and projects have rekindled an interest in building projects that was somehow lost in the midst of drought and the generally tough times associated with the business of farming. On the subject of projects, I remember years ago there was a car trip computer kit made available for petrol cars. It was quite successful and certainly a useful project. Trip computers in petrol powered motor vehicles are quite commonplace these days but what about diesel-fueled cars, trucks and 4WDs? There is the problem of taking into account the unburned fuel returned to the vehicle’s fuel tank from the injection system, unlike petrol-powered vehicles. I am aware that large trucks and at least one very expensive European diesel-powered 4WD are fitted Virtually all the “unused holes” are plated-through “vias” which connect the PC patterns on both sides of the board. Feeding the voice recorder from a PC I have a question about the Voice Recorder kit from the May 2005 issue. Can this kit be modified to accept a 3.5mm headphone jack from a PC (the sound card line-out)? It’s better to transfer a sound recording via a PC’s sound card, rather than the kit’s microphone. (S. M., via email). • It is quite easy to modify the Solid State Voice Recorder to accept linelevel signals like those from a PC sound card, instead of the electret microphone. To do this, omit the microphone insert itself and also the 10kW resistor which is used to supply the mic with DC bias. That done, connect the 10kW resistor across the two terminal pins used for the mic and feed the line-level audio into the ‘+’ mic pin via a series 220kW resistor (from the ‘tip’ connection of a with such devices. With the cost of diesel escalating on a seemingly daily basis, would it not be a good time to consider developing a trip computer kit for diesel-powered vehicles? (S. L., via email). • Virtually all recent model petrolpowered cars these days use fuel injection and just about all of them also have a bypass back to the fuel tank from the fuel rail, as in diesel engines. The fuel rate is measured with respect to the duty cycle of the fuel injectors (on the assumption that the fuel rail pressure is constant). On that basis, any car computer designed for petrol vehicles would be equally applicable to diesels. You can get more background on this subject in our book “Performance Electronics for Cars”. However, we have no plans to produce a car computer and cannot see any easy way of calculating fuel flow vs injector duty cycle for the vast range of vehicles on the market. 3.5mm mono plug). Connect the earthy side of the line level audio input (from the “sleeve” connection of the plug) to the second mic terminal pin, and that’s it. The line level audio will now feed into the Recorder’s mic input, via a 23:1 voltage divider which prevents overload. Video reading aid for NTSC systems I refer to the Video Reading Aid in the October 2005 issue. My mother has macular degeneration and this looks like it may be really helpful for her. The only problem is that I need it to work in NTSC format, not PAL. Any chance of a revision of the unit to make it work here in the USA? (K. W., Penndel, PA, USA). • The Video Reading Aid should work quite happily with NTSC signals as it is. It’s really only using B&W video and the LM1881 sync separator chip works with NTSC line and field rate signals just as well as it does with those for a PAL signal. Of course, you’ll need to use a November 2005  107 Fan-Forced Heatsink For SC480 Amplifier I am building a couple of your SC480 amplifier modules and am thinking of using a fan-forced channel heatsink. In general, how can you determine the thermal resistance of a heatsink when a fan is attached? Also, is it possible to find the thermal resistance of a heatsink if I was to cut a longer one into smaller sections, as I find that there is linear (or other common) relationship between thermal resistance and length? (Y. P., Perth, WA). • Typically, this information would be gleaned from the heatsink 115VAC/12V DC plugpack (wall transformer) to power the unit and also use a mini CMOS camera which is compatible with NTSC TV sets. But otherwise the project should work quite happily in the USA without any other modifications. Nilsen battery charger repair I have an old Nilsen 12/6V 4A battery charger, still in good nick but the DC voltage is low and I suspect that the metal plate rectifier has gone faulty. Would it be OK to replace this rectifier with a modern bridge rectifier? I happen to have a 35A encapsulated bridge rectifier on a metal heatsink which would be easy to fit. I will also replace the exposed 3AG 5A fuse with an enclosed type. Do you think it would be a good idea to insert a series diode of appropriate size for reverse manufacturer’s data sheets, which graph air velocity, heatsink temperature rise, power dissipation, thermal resistance, etc. Without such detailed data, you will need to rely on empirical methods. Regarding the cutting of a heatsink, if you’re dividing it into large, symmetrical sections, you’ll probably find that the thermal rating for each of the smaller pieces relates quite well to the original section. A handy “Heatsink Basics” document can be found at www1.jaycar. com.au/primers.asp polarity connection protection? I know this will have a forward voltage drop but it’s only for occasional emergency use. (B. P., via email). • You can certainly replace the bridge rectifier but check that the output is not too high after you do so. The old metal plate (copper oxide?) rectifiers had a much high voltage loss than silicon rectifiers. There is no point in installing an extra diode for reverse protection. As far as the bridge rectifier is concerned, it is already inherently protected against reverse current from the battery. And the fuse will protect against excessive current from the charger if you connect the battery incorrectly. UHF animal tracking I am an apprentice Electrical Technician at Alcoa. Each year, we do an ap- prentice project and this year I would like to make a dog tracker. This is used when hunting, so you can locate the dogs over long distances. The transmitter is designed to be attached to the dog’s collar and the receiver is hand-held. I am having trouble finding a design and circuit diagram to make it from. If you can help me out, it would be much appreciated. (E. J., Waroona, WA). • You’re probably thinking of the familiar radio system used to track animals. This is normally done with a UHF transmitter modulated with a tone. The transmitter is fitted to the animal and has a short antenna. It is then tracked with a fairly large UHF Yagi antenna (to enable direction-finding) which feeds the receiver which you listen to. Have we published suitable circuits? No – but you could probably adapt the cheap UHF CB handheld radios availSC able from DSE, Jaycar, etc. Notes & Errata Battery Zapper, July 2005: this project must not be permanently installed across the battery in a car or any other vehicle. The high voltage pulses it generates could easily damage the electronics in the vehicle. Alcohol Level Meter, October 2005: The text on page 71 regarding a standard drink being a 200ml nip of spirits is wrong. A standard drink contains 10g of alcohol such as in a 285ml glass of full strength beer or a 30ml measure of spirits. WARNING! SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Trade Practices Act 1974 or as subsequently amended and to any governmental regulations which are applicable. 108  Silicon Chip siliconchip.com.au MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. FOR SALE more items being added. New webshop now online! www.ledsales.com.au SUPERBRIGHT LEDS from just 15 cents each, including new wide angle range! 12 volt LED lightbars, great for solar/camping. Nixie tubes and nixie clock kits. Lots of other stuff, and always WEATHER STATIONS: windspeed & direction, inside temperature, outside temperature & windchill. Records highs & lows with time and date as they occur. Optional rainfall and PC interface. Used CLASSIFIED ADVERTISING RATES Advertising rates for this page: Classified ads: $22.00 (incl. GST) for up to 20 words plus 66 cents for each additional word. Display ads: $36.00 (incl. GST) per column centimetre (max. 10cm). Closing date: five weeks prior to month of sale. To run your classified ad, print it clearly in the space below or on a separate sheet of paper, fill out the form & send it with your cheque or credit card details to: Silicon Chip Classifieds, PO Box 139, Collaroy, NSW 2097. Alternatively, fax the details to (02) 9979 6503 or send an email to silchip<at>siliconchip.com.au Taxation Invoice ABN 49 003 205 490 _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Enclosed is my cheque/money order for $­__________ or please debit my o Bankcard   o Visa Card   o Master Card Card No. Signature­­­­­­­­­­­­__________________________ Card expiry date______/______ Name _____________________________________________________ Street _____________________________________________________ Suburb/town ___________________________ Postcode______________ Phone:_____________ Fax:_____________ Email:__________________ siliconchip.com.au by government departments, farmers, pilots and weather enthusiasts. Other models with barometric pressure, humidity, dew point, solar radiation, UV, leaf wetness, etc. Just phone, fax or write for our FREE catalog and price list. Eco Watch phone: (03) 9761 7040; fax: (03) 9761 7050; Unit 5, 17 Southfork Drive, Kilsyth, Vic. 3137. ABN 63 006 399 480. 18 YEARS OF SILICON CHIP WITH BINDERS: First edition to end 2005. Enquiries to (07) 3201 4976. MORE CONTROL SOLUTIONS for you: Netiom Link – automatically transfer digital inputs and outputs between two cards over an Ethernet link. Labjack USB Data Acquisition Module features 8 12-bit analog inputs, 20 digital I/O, 2 analog outputs and high speed counter. Free software DaqFactory Express, Labview driver and ActiveX component. Signal Conditioners non isolated and isolated – convert thermocouples, RTDs to 4-20mA or 0-10V. Fully programmable. Pixel Programmable Controller with 4 analog inputs, 8 digital inputs and 8 relay outputs. Uses a Picaxe 28X. Programmed in BASIC. Temperature and humidity sensors N1500 universal process indicator. Budget-priced displays thermocouple, RTD, 4-20mA and 0-5V readings. Fully programmable. Box of Connectors – choose BNC, UHF, N Type or RS232 gender changers and converters together. Serial and Parallel port relay controller cards. Pump and Trip Alarm Controller card. Duty-Standby operation. MicroProgrammers for Atmel and PIC chips. 2, 4 & 8 Relay Cards suitable for TTL and Open Collector Outputs DC, Stepper and Servo Motor controller kits. Switch-Mode, Battery Chargers and DC-DC converters. Full details and credit card ordering available at www.oceancontrols.com.au Helping to put you in control. November 2005  109 New New New Mark22-SM Slimline Mini FM R/C Receiver Wi-Fi 2.4GHz Antennas Directionals Omnis We also stock: • • • • • Panel Antennas Ceiling Antennas Low-loss 50 Ω cable Connectors Pigtails Access Points Masts Amplifiers Power-over-Ethernet External Enclosures Everything you need for WiFi! 6 Channels 10kHz frequency separation Size: 55 x 23 x 20mm Weight: 25gm Modular Construction Price: $A129.50 with crystal Electronics PO Box 580, Riverwood, NSW 2210. Ph/Fax (02) 9533 3517 email: youngbob<at>silvertone.com.au Website: www.silvertone.com.au FREENET-ANTENNAS Web: www.freenet-antennas.com Email: sales<at>freenet-antennas.com Tel: (08) 9319 3275 (int +618 9319 3275) Fax: (08) 9319 1720 (int +618 9319 1720) Select your microcontroller kit and get started... Fax a copy of Foam surrounds,voice coils,cones and more Original parts for Dynaudio,Tannoy and others Expert speaker repairs – 20 years experience Australian agents for products Trade welcome – email for your user ID Phone (03) 9647 7000 From $295* RCM3400 this ad and receive a 5% discount on your order! CLEVERSCOPE USB OSCILLOSCOPES 100MSa/s 10bits each channel 4M samples per input 100MHz bandwidth 8 digital inputs Sig-gen option Spectrum analyser Windows 98/Me/NT/2k/XP GRANTRONICS PTY LTD PO Box 275, Wentworthville. 2145. Ph: 02 9896 7150 www.grantronics.com.au • Prices exclude GST and delivery charges. Tel: + 61 2 9906 6988 Fax: + 61 2 9906 7145 www.dominion.net.au PCBs MADE, ONE OR MANY. Any format, hobbyists welcome. Sesame Electronics Phone (02) 9593 1025. sesame<at>sesame.com.au www.sesame.com.au USB KITS: GPIB Interface, Thermostat Tester, LCD Module Interface, Stepper Motor Controller, PIO Interface, DTMF Transceiver, Thermometer, DDS HF Generator, Compass, 4 Channel Voltmeter, I/O Relay Card, USB via LabVIEW. Also available: Digital Oscilloscope, Temperature Loggers, VHF Receivers and USB ActiveX (and USBDOS.exe file) to control our kits from your own application. www.ar.com. au/~softmark 110  Silicon Chip AV-COMM P/L, 24/9 Powells Rd, Brookvale, NSW 2100. Tel: 02 9939 4377 or 9939 4378. Fax: 9939 4376; www.avcomm.com.au Feature rich, compiler, editor & debugger with royalty free TCP/IP stack speakerbits.com.au ImageCraft C Compilers: 32-bit Windows IDE and compiler. For AVR, 68HC­08, 68HC11, 68HC12, 68HC16. from $330.00 Atmel Flash CPU Programmer: Handles the 89Cx051, 89C5x, 89Sxx in both DIP and PLCC44 and some AVR’s, most 8-pin EEPROMS. Includes socket for serial ISP cable. $220, $11 p&p. SOIC adaptors: 20 pin $132.00, 14 pin $126.50, 8 pin $121.00. Full details on web-site. Credit cards accepted. GRANTRONICS PTY LTD, PO Box 275, Wentworthville 2145. (02) 9896 7150 or http://www.grantronics. com.au Satellite TV Reception International satellite TV reception in your home is now affordable. Send for your free info pack containing equipment catalog, satellite lists, etc or call for appointment to view. We can display all satellites from 76.5° to 180°. 4007 S-Video . . . Video . . . Audio . . . VGA distribution amps, splitters, standards converters, tbc’s, switchers, cables, etc, & price list: www.questronix.com.au SPICE UP YOUR PARTS DRAWER! RF, Microwave and Audio parts by MiniCircuits, HP, Motorola, Vishay, Infineon and many more. Vintage & modern, rare Best high end DIY audio kits on the planet! www.aksaonline.com & unusual. http://rfplus.jonwright.org or ‘rfplus’ on Ebay. Limited quantities. Come take a look before they’re gone! RCS RADIO/DESIGN is at 41 Arlewis St, Chester Hill 2162, NSW Australia and has all the published PC boards from SC, EA, ETI, HE, AEM & others. Ph (02) 9738 0330. sales<at>rcsradio. com.au, www.rcsradio.com.au NOKIA LCD SCREENS: DIY replacement for all Nokia models with tools and instructions at www.idatic.com.au Ph 0407 902 600. WANTED WANTED: EARLY HIFIs, AMPLIFIERS, Speakers, Turntables, Valves, Books, Quad, Leak, Pye, Lowther, Ortofon, SME, Western Electric, Altec, Marantz, siliconchip.com.au Do You Eat, Breathe and Sleep TECHNOLOGY? Opportunities for full-time and part-time positions all over Australia & New Zealand Jaycar Electronics is a rapidly growing, Australian owned, international retailer with more than 39 stores in Australia and New Zealand. Our aggressive expansion programme has resulted in the need for dedicated individuals to join our team to assist us in achieving our goals. We pride ourselves on the technical knowledge of our staff. Do you think that the following statements describe you? Please put a tick in the boxes that do: Knowledge of electronics, particularly at component level. Assemble projects or kits yourself for car, computer, audio, etc. Have empathy with others who have the same interest as you. May have worked in some retail already (not obligatory). Have energy, enthusiasm and a personality that enjoys helping people. Appreciates an opportunity for future advancement. Have an eye for detail. Why not do something you love and get paid for it? Please write or email us with your details, along with your C.V. and any qualifications you may have. We pay a competitive salary, sales commissions and have great benefits like a liberal staff purchase policy. Send to: Retail Operations Manager - Jaycar Electronics Pty Ltd P.O. Box 6424 Silverwater NSW 1811 Email: jobs<at>jaycar.com.au Jaycar Electronics is an equal opportunity employer and actively promotes staff from within the organisation. Advertising Index 555 Electronics.............................67 Altronics........................ loose insert Aspen Amplifiers........................110 ATA...............................................97 Av-Comm...................................110 Delta Audio...................................35 Dick Smith Electronics........... 20-25 Dominion Electronics..........105,110 Eco Watch..................................110 Elexol...........................................67 • • •           TAIG MACHINERY Micro Mini Lathes and Mills From $489.00   Evatco........................................105 Farnell Electronics....................OBC FreeNet Antennas......................110 Furzy Electronics........................111 Grantronics.................................110 Harbuch Electronics.....................99 Instant PCBs..............................111   Jaycar ...............IFC, 49-64,101,111 JED Microprocessors..............5,101 Laceys TV..................................111  Microbric......................................17   Microgram Computers....................3 • • • • •     MicroZed Computers....................95 NewTek Instruments.......................7 Ocean Controls..........................109 Ozitronics.....................................97 Prime Electronics.........................69 Measure DTV S22 Quest Electronics................101,111 Radiometrix....................................6 RCS Radio.................................109 Stepper motors: 200 oz in $89.00, 330 oz in $110.00 Digital verniers: 150mm $55.00, 200mm $65.00 59 Gilmore Crescent (02) 6281 5660 Garran ACT 2605 0412269707 RF Modules................................101 FOXTEL APPROVED RF Probes....................................97 SC Perf Elect. For Cars................98 Silicon Chip Binders................87,89 McIntosh, Goodmans, Wharfedale, Tannoy, radio and wireless. Collector/ Hobbyist will pay cash. (02) 9440 1267. johnmurt<at>highprofile.com.au WANTED: ONE OR MORE light dependent resistors type RPY20. Advise price and availability to 08 8339 2330. FERGUSON OPM7A ULTRALINEAR VALVE PUSH-PULL AUDIO OUTPUT TRANSFORMER: one only required, must be in full working condition (no opens or shorts), will pay up to $100. Contact Rod on (0400) 945 152, 08301700 Eastern Summer Time, Mondays to Fridays. siliconchip.com.au Silicon Chip Bookshop........112,IBC Silicon Chip Subscriptions...........48 42 Brunel Rd Seaford VIC 3198 Tel (03) 9776 9222 Fax (03) 9776 9766 web:www.laceys.tv e-mail:info<at>laceys.tv branches: Sydney Ulverstone Woolgoolga Silvertone Electronics................110 Siomar Batteries..........................35 Speakerbits................................110 Taig Machinery...........................111 KIT ASSEMBLY NEVILLE WALKER KIT ASSEMBLY & REPAIR: • Australia wide service • Small production runs • Specialist “one-off” applications Phone Neville Walker (07) 3857 2752 Email: flashdog<at>optusnet.com.au Telelink.......................................101 ____________________________ PC Boards Printed circuit boards for SILICON CHIP projects are made by: RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. November 2005  111 ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. PRACTICAL RF HANDBOOK AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* Alternative fuel expert Carl Vogel gives you a hands-on guide with A guide to RF design for engineers, technicians, students and enthusiasts. the latest technical information and easy-to-follow instructions Covers key topics in RF: analog design principles, transmission lines, for building a two-wheeled electric vehicle – from a streamlined couplers, transformers, amplifiers, oscillators, modulation, transmitters and scooter to a full-sized motorcycle. 384 pages in soft cover. receivers, propagation and antennas. 279 pages in paperback. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. PRACTICAL RF HANDBOOK AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* Alternative fuel expert Carl Vogel gives you a hands-on guide with A guide to RF design for engineers, technicians, students and enthusiasts. the latest technical information and easy-to-follow instructions Covers key topics in RF: analog design principles, transmission lines, for building a two-wheeled electric vehicle – from a streamlined couplers, transformers, amplifiers, oscillators, modulation, transmitters and scooter to a full-sized motorcycle. 384 pages in soft cover. receivers, propagation and antennas. 279 pages in paperback. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST