May 2004 - Silicon Chip Online

Outer Front Cover
Contents
Publisher's Letter: High-priced power cords another fraudulent product
Feature: The Robocup – Robots Play Soccer by David Perry
Feature: Amplifier Testing Without High-Tech Gear by Julian Edgar
Project: Component Video To RGB Converter by Jim Rowe
Feature: Fly Rabbit Fly - Right Up To The Sky
Project: StarPower: A Switching Supply For Luxeon Star LEDs by Peter Smith
Project: Wireless Parallel Port by Nenad Stojadinovic
Vintage Radio: Cataloging & disposing of your collection by Rodney Champness
Feature: Fluid Lenses – The New Way To Focus by Silicon Chip
Project: Poor Man's Metal Locator by Thomas Scarborough
Book Store
Advertising Index
Outer Back Cover

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siliconchip.com.au May 2004 1 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings.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.17, No.5; May 2004 FEATURES 8 The Robocup – Robots Play Soccer www.siliconchip.com.au Amplifier Testing Without High-Tech Gear – Page 18. Robots playing soccer? You’d better believe it and there’s more than one league to play in – by David Perry 18 Amplifier Testing Without High-Tech Gear You don’t need expensive gear to check out the performance of your hifi amplifier. Here’s how to do it for peanuts – by Julian Edgar 38 Fly Rabbit Fly – Right Up To The sky Yes, rabbits really can fly, especially when strapped into a rocket. But there’s no fur, cotton tails or long ears involved here 78 Fluid Lenses – The New Way To Focus Unique variable-focus optical lens system has no moving parts and could revolutionise digital cameras and security systems PROJECTS TO BUILD 24 Component Video To RGB Converter Does your TV have RGB instead of component video inputs? This project lets you get the best possible pictures from your DVD player – by Jim Rowe 58 StarPower: A Switching Supply For Luxeon Star LEDs It’s based on a switching regulator IC, runs of 12V and is just the shot for powering 1-5W Luxeon Star LEDs – by Peter Smith 66 Wireless Parallel Port Low-cost design uses a 433MHz UHF data link and can be used to control an 8-channel relay board – by Nenad Stojadinovic 80 Poor Man’s Metal Locator It uses just five circuit components, is easy to build and works on the “beat balance” principle for good sensitivity – by Thomas Scarborough Build A Component Video To RGB Converter – Page 24. StarPower: For Luxeon Star LEDs – Page 58. SPECIAL COLUMNS 33 Circuit Notebook (1) Exit Sign With Battery Protection; (2) One ADSL Filter Serves Several Phones; (3) PICAXE-Based Home Security Project; (4) PICAXE-Based Car Speed Alarm; (5) Low-Cost Low-Intensity Alarm 40 Serviceman’s Log Nothing succeeds like a good whinge – by the TV Serviceman 73 Vintage Radio Cataloging & disposing of your collection – by Rodney Champness DEPARTMENTS 2 4 44 53 57 Publisher’s Letter Mailbag Order Form Product Showcase Silicon Chip Weblink siliconchip.com.au 85 89 94 96 Ask Silicon Chip Notes & Errata Market Centre Ad Index Wireless Parallel Port – Page 66. Poor Man’s Metal Locator – Page 80. May 2004 1 PUBLISHER’S LETTER www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Peter Smith Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Reader Services Ann Jenkinson Advertising Enquiries Leo Simpson Phone (02) 9979 5644 Fax (02) 9979 6503 Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Julian Edgar, Dip.T.(Sec.), B.Ed 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: $76.00 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial & advertising offices: 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 ISSN 1030-2662 * Recommended and maximum price only. 2 Silicon Chip High-priced power cords another fraudulent product Every now and again a reader will send me a letter highlighting the fact that high-priced speaker leads and other hifi accessory products continue to be sold by hifi retailers. In fact, there is a letter on this topic in this month’s Mailbag pages. These days I just tend to shake my head in continuing amazement at the apparently endless ignorance and gullibility of customers and the completely shameless exploitation of this credulousness by some hifi retailers. We’ve seen it all before: oxygen free speaker cables with long grain copper; Litz-wound cables to avoid high frequency skin effect; directional interconnects; special video cables and so on. All wrapped up with technical-sounding mumbo-jumbo designed to confuse the already muddle-headed customer with money burning a hole in his pockets. Considering their willingness to sell this high-priced rubbish, some hifi retailers make car salesman and real estate agents look like honest people. I will go further: How can you trust the recommendations of any hifi dealer who sells these accessories? One recent “innovation” involves interconnect cables with a 12V or 24V battery or 48V supply to supposedly bias the cable’s dielectric. You can also have biased speaker cables, ranging from $1415 to $14,715 a pair. The shyster who promotes this nonsense maintains that the “reason your equipment and cables sound better when you leave the power turned on...is because you are partially biasing the dielectric material in every component.” What can I say? It leaves me speechless. The whole product category should probably be referred to Consumer Affairs. They could have a field day with it. In their defence, hifi retailers will probably state that all their customers who buy these high priced cables are highly satisfied, with no complaints. Of course that is to be expected, isn’t it? If an ignorant person buys a technical product with an expectation that it will sound better, it is no surprise that he thinks it does sound better. And if it doesn’t, he is not likely to admit that he has been dudded. But perhaps the worst example of hucksterism has to be the recent emphasis on special power cords, as produced by companies such as Shunyata Research. We are talking real money here; hundreds of dollars for a power cord! I really think the principal of the company must be laughing up his sleeve (and all the way to the bank) at his feckless customers. Shunyata, usually translated as “emptiness”, “voidness”, “nothingness” or even “relativity”, is a key technical and philosophical term in the Mahayana Buddhist tradition. You don’t believe me? Just do a Google search on “shunyata”. To top it off, all the product lines are named after snakes. Is that “snake oil” or what? Even worse, there is an Australian company in on the act. Just goes to show that when it comes to making a buck, Aussie companies are right up there. Worst still, overseas “hifi” magazines such as the “Absolute Sound” give ringing endorsements to these products. It makes you wonder what special medication they are taking. Or what kickbacks? Perhaps the final comment should come from my good friend Poul Kirk at Elan Audio, specialist audio manufacturer. As a joke, he has put together a power cord which passes through a black plastic box. The box is supposedly filled with specially imported elephant poo. He says that poo from Australian elephants just isn’t good enough. Perhaps the imported elephant poo has added impurities from wildebeest (Gnu poo?) for special dielectric doping effect. Whatever. But you can bet that Poul Kirk’s special power cord would “sound” at least as good, and possibly even better, than anything from Shunyata Research. I will leave you to draw your own conclusions. Leo Simpson siliconchip.com.au Computer bits? We’ve got the lot! LCD Monitor Arm Holds 14”, 15” & 17” LCD monitors. Supports up to 8kg. 3 in 1 design desktop, wall and clamp mounting. Standard VESA mounts. Cat 4666-7 Monitor Arm $99 Cat 4666 DVI KVM Switches A KVM switch to share a DVI monitor, PS/2 keyboard & mouse with two computers. Cat 11663-7 2 way DVI PS/2 - KVM Switch $169 This USB connected phone allows free calls across the internet using third party software. Just plug into a USB port, no drivers needed. Operates with NetMeeting, MSN Messenger, Skype etc. Cat 10129-7 USB Net Phone $89 Cat 17074 Cat 1149 This very small footprint computer measures only 330x280x100 and utilises a standard ITX motherboard Cat 1149-7 $499 Micro Footprint PC For mobile or remote site applications, this computer only needs a 12 Volt suppply Cat 1150-7 $749 12 Volt Embedded PC Cat 11907 Go hands free with your bluetooth phone. Cat 11907-7 Head Set $199 Lets your computer receive information and control a large range of external devices even from a remote location. Cat 17074-7 8 CH Opto DI 8 CH Relay Output PCI Dec $399 Micro Computers/PXE Terminals USB Net Phone Bluetooth Head Set Opto In Relay Out PCI VGA Splitters Bluetooth Serial Cable Replacement Cash Drawer This module is unique! Turn any serial device into a wireless device with this bluetooth adapter for the device end Cat 11908-7 Serial Cable $459 Replacement Device A robust metal construction casing with adjustable dividers for four or five compartments, and a separate coin tray. Compatible with Star, Epson and Citizen POS printers Cat 8897-7 Cash Drawer $199 Pole Displays Front Access PC Card Drive This unit is an ATA Flash card drive which connects to the IDE connector of a standard PC. It reads full size ATA flash cards and supports Win98/ME/2000/XP. Cat 6668-7 PC Card Drive Hot Swap $99 Front Access PCMCIA Drive Cat 6482 This “drive” supports two type I or one Type II card with full PCMCIA compatibility. Cat 6482-7 PCMCIA Drive Front Access $321 Cat 6523 PC CardBus Sockets Transfer your PC CardBus (32 bit) and PCMCIA (16 bit) based data to your desktop PC. This “drive” has two rear slots and supports Type I, Type II and Type III PC Cards. Cat 6523-7 PC CardBus Drive $199 These customer displays are designed for POS application and are driven from a serial port. Cat 8728-7 POS customer display 11.2mm $359 $269 Cat 8907-7 POS customer display 9mm Cat 4658 Cat 8907 POS LCD Monitors When space is at a premium these POS displays will do the job. With a resolution of 800 x 600 they connect directly to a VGA output. An integrated touch screen is optionally available. Cat 4658-7 12.1” LCD Monitor $969 $999 Cat 4683-7 10.4” LCD Monitor Citizen POS Receipt Printers These quality Citizen printers offer a reliable solution for the most demanding POS situations. Bi-directional and available in both Serial and Parallel. Cat 5694-7 IDP3420 with tear bar - Serial $479 IDP3420 with tear bar -Parallel $479 Cat 5695-7 Cash Registers Affordable Registers for small retail and speciality stores, with highly visible operator displays. Cat 1008129-7 Sharp XE-A101 $289 $589 Cat 1008138-7 Sharp XE-A202 USB Smart Card Reader/Writer The package includes API Library, Demo Program and Demo Source code and is suitable for applications in security control, loyalty programs, EDI, Kiosks, PKI and eCommerce etc. Cat 8981-7 Smart Card Reader/Writer - USB Fast POS Thermal Printer $139 Dual Video Capture Card Cat 1008138 A very fast thermal printer with extremely easy paper loading. It literally churns out the receipt at 180 mm/s. Comes with a parallel Interface. Gray or Black available. Cat 9177-7 POS Thermal Printer $799 Watch Dog Timer If your application program locks up, these watch dogs will apply a hardware reset to the computer after a selectable period. Cat 17070-7 Watch Dog Timer Card PCI $332 $199 Cat 17084-7 USB Auto reset - Watchdog Touch Screen Overlay for 15in LCD This touch screen fits over the front of an LCD display and connects to the PS/2 port of a pc. Mouse software drivers are included. Cat 4353-7 Monitor Touch Screen PS/2 $699 Throw away your old fashioned keys...use RFID $199 $259 $379 Cat 1008079 RFID (Radio Frequency Identification) is the new contactless way of opening doors, tracking goods, etc. Cat 1008082-7 Electrically operated door lock Cat 1008081-7 All in one controller & sensor Cat 1008079-7 Stand alone controller Cat 1008080-7 RFID reader 80mm range Cat 1008057-7 RFID reader 200mm range Cat 1008108-7 RFID reader RS232 connection Cat 1008083-7 RFID card 0.8mm thick Cat 1008058-7 RFID card 1.8mm thick Cat 1008059-7 RFID key-tag $189 $349 $269 $209 $269 $199 $4.50 $3.25 $6.50 RFID & Finger Print Readers Control access to your premises and maintain a record of all comings and goings. Virtually any combination of Keypad PIN, RFID tag and/or fingerprint reader can provide the level Cat 1008142 of security you choose. Optional access managment software allows control via an RS232 or RS485 link to a PC.. Cat 1008142-7 RFID & Finger Print Reader/Controller $1,999 Cat 1008143-7 RFID Reader/Controller - LCD Display $549 $399 Cat 1008145-7 Access Control Software Cat 9177 Cat 5448 Bar Code Laser Gun An integrated DV (digital video) and AV (analog video) input all-in-1 PCI interface card. Cat 3526-7 Two in One - DV and AV $249 These splitter modules enable multiple monitors to share the same information off a host PC simultaneously. The units also boost the VGA signal allowing distances up to 75m from the local machine. Cat 3070-7 VGA Splitter 2 way Max Distance 75m VGA Splitter 4 way Max Distance 50m Cat 3055-7 VGA Splitter 8 way Max Distance 50m Cat 3056-7 A very competitivey priced laser bar code reader with excellent performance - and it looks the part too. It will interface as a keyboard Cat 1008039 wedge, USB or serial device by simply changing the configuration and the cable. Cat 1008039-7 Bar Code Laser Gun $399 Omni-Directional Laser Scanner Get the same bar code reading capability as the big super markets! An affordable, vertically mounted, small footprint, omni-directional laser scanner. It is ideally suited to checkouts of all types, eg newsagents, convenience stores etc. Cat1008085-7 Omni-Directional Laser Scanner $999 Business Card Cutter Design, print and cut your own business cards. Our kit consists of Business Card Design Software, 50 sheets of high quality business card paper (500 business cards) and a business card cutting machine. Cat 5448-7 Business Card Cutter $249 Cat 3496 Surveillance Equipment Keep an eye on things with our range of surveillance equipment. Cat 3429-7 4 Camera Input Kit $899 Cat 3491-7 Dome Style colour camera $249 $96 Cat 3489-7 Dome Style B&W camera Cat 3496-7 B&W camera - IR Illumination $114 IP Addressable Cameras Run an ethernet connection straight from the camera to monitor your video feeds locally or remotely. Cat 3487-7 Cat 5 connected camera $669 $1099 Cat 3475-7 Wireless camera Thin Client Terminals! We’ve got them for Serial, Ethernet, Windows Based and Linux applications MicroGram Computers Ph: (02) 4389 8444 FreeFax: 1800 625 777 Vamtest Pty Ltd trading as MicroGram Computers ABN 60 003 062 100, info<at>mgram.com.au 1/14 Bon Mace Close, Berkeley Vale NSW 2261 All prices subject to change without notice. For current pricing visit our website. Pictures are indicative only. See all these products & more on our website...www.mgram.com.au SHOREAD/MGRM0304 Dealer inquiries welcome MAILBAG Digital TV has aspect ratio problems Being the owner of a wide-screen TV connected to a digital set top box probably puts me in the minority for the moment among TV viewers. This may be the reason why a current problem with digital TV aspect ratio is receiving no comment from the viewing public. The problem is that some TV programs and commercials on all channels, when viewed on a wide-screen TV, are wide-screen (16:9) but are shrunk, meaning that there is a black border all the way around. It is as if you need a zoom control to zoom in on the picture so it will fill the complete screen. After considerable contact with SBS, who have this situation more than other channels, the answer was figured out. It took some doing, as my original queries were not understood and I received a lot of information about aspect ratios but not about the problem. After photographing my analog 4:3 and digital 16:9 TV pictures when this condition existed, the problem was understood (by SBS). TV in Australia is in transition, not just with analog to digital but also 4:3 to 16:9 and this change of aspect ratio is a difficult one when the TV stations have to try and satisfy two different consumer demands. Only the Nine and Ten networks have full 16:9 studio capabilities, while the others have limited 16:9 studio capabilities or none. For example, some two years on, only channels Nine and Ten transmit their news in 16:9 on the digital service. When a program is fundamentally 4:3 but with inserts of 16:9 material, there are two options: (1) crop off the sides of the 16:9 picture; or (2) show the 16:9 material in letterbox format. This means that the 4:3 analog viewer sees the studio-based picture (for example, the presenter) in 4:3, filling the screen with no missing picture. When the 16:9 inserted material is then shown, the analog viewer sees this material in letterbox with a black bar at the top and bottom. This is 4 Silicon Chip because the program people want the analog viewer to see all of the 16:9 picture. But what happens for the digital viewer? The digital viewer sees the studio-based program (the presenter) in 4:3, meaning a black bar on the left and right but not on the top and bottom. However, when the 16:9 inserted material is shown, which is now treated as letterbox, the picture remains “4 units” wide (black bar on left and right) but now has a black bar at the top and bottom as well in order to maintain a 16:9 aspect ratio (ie, it gives a small 16:9 picture). It may be difficult to get your head around the problem, as it is a complex mix of different aspect ratios. There is a solution, other than convert the studio to 16:9, and that is an aspect ratio converter on the digital transmission feed that is switched to convert letterbox to 16:9. This however has its own problems, one of them being cost. By the way, owners of 4:3 TV sets connected to a set-top box and set up for 16:9 viewing on the set top box and the TV experience the same problem. So if you have wondered why you have a brand new wide-screen TV but with a shrunken picture, it is because of the difficulty of mixing 4:3 and 16:9 during this transition phase. Will McGhie, Lesmurdie, WA. Uninsulated wiring a hazard for current clamp adaptor I am assembling the current clamp adaptor for DMMs, as described in the September 2003 issue. It occurred to me that the insulation of the supplied battery clip (as used in the original project) may not be adequate when measuring current in high voltage AC/ DC circuits. As an industrial electrician, I frequently use a “clip-on” in control cabinets, etc where there is a possibility of contact with the 240VAC mains. Employer provided clamp-meters have insulated jaws. There appears to be no mention of the possibility of an electric shock or creating an arc when using this type of clip. The toroid ring provided is also conductive. I have purchased another larger all-insulated battery clip from Jaycar that should be safe. I will shift the Hall Effect sensor to the pivot end of the clip. Can it be mounted in-line with the toroid ring? The original setup is mounted at 90° to the toroid. I. J. McPherson, via email. Comment: we should have mentioned that the clamp adaptor is not suitable for use with 240VAC mains when the wiring is uninsulated. The Hall Effect sensor detector can be rotated 90° as you suggest. If cars were priced like VCRs . . . Recently, I bought a $98 Dick Smith branded VCR from Tandy. I can’t believe that this good-looking, feather-light 14W 4-head machine could be had for one-sixteenth the dollar price I paid for my first VCR over 20 years ago! And it comes with a crystal-locked 30-odd channel UHF modulator – no stupid “Video/TV” switches required. If car pricing went the same way, we’d be able to buy a basic sedan now for around $1,000! Peeping inside, it’s obviously been built by robots and as for more than basic repairs, forget it! But at that price who cares? What I was curious about is whether you’ve heard if there has been some sort of relaxation of the RF standards required for the importation of TV receivers into Australia. When just about all of Europe standardised on a video IF of 38.9MHz in siliconchip.com.au the early 60s, the Australian authorities decided upon the oddball frequency 0f 36.875MHz. The theory behind this seemed sound enough at the time: nobody in Australia would transmit anything on that frequency, reducing the possibility of mutual interference. Back when TV sets used valves, this may have been a valid concern but such problems have long since vanished with the proliferation of SAW filters and compact IC IF amplifiers. However, at least in the early days of colour TV, it no doubt served as a convenient excuse to make things just that little bit more difficult for importers, since TVs would have be specifically made in smallish batches for the Australian market! Recently I’ve noticed that all seems to have gone out the window, and even bargain-basement TVs and VCRs seem to be able to be set up to work anywhere in the PAL world! A $148 14-inch TV I also recently bought worked faultlessly on PAL, NTSC (both 4.43MHz and 3.58MHz) and PAL-M! There are no glass delay lines, coils or filters either, just one big SMD IC and two crystals. It’s all done by switchedcapacitor filters and delay lines. And done very well! And with none of your fancy subcarrier-multiple crystals either, just bog-standard 4.43MHz and 3.58MHz rocks! They don’t even have trimmer capacitors! And where I can actually get a look at the IF SAW filter, they all now seem to be the Euro-standard 38.9MHz. In most cases now, the IF and tuner are all in one unit which makes prying a trifle difficult these days. It says something about economies of scale, doesn’t it? Already, most DVD players can be set up to operate as PAL or NTSC machines. In a few years I can see TVs and VCRs becoming truly “international” with tuners that can handle just about any VHF or UHF transmission, or standard, whether digital or analog. It’s also been some years since I’ve seen a TV or VCR that doesn’t work perfectly with a mains supply anywhere from 80VAC to over 260VAC (which is as high as my Variac goes). Keith Walters, via email. Comment: we don’t know of any specific relaxation but it occurs to us that siliconchip.com.au provided a TV, VCR or whatever met the various safety standards and could be demonstrated to “work” satisfactorily on Australian transmissions, then local distributors would have no compunction about releasing the product on our market. 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 Expensive loudspeaker cables are a con It was interesting to read the Publisher’s Letter in the February 2004 issue, about the cons of electronic corrosion control. Another con that I feel is being promoted by some hifi and electronic component stores relates to the use of “monster cable” for speaker connections. In a normal home situation I cannot see the justification for using such expensive cable when possibly good twin-core flex (say 7.5A rating) would suffice. I would defy anyone (with good or poor hearing) to pick the difference in sound quality between one system using “monster cable” and another using good twin-core flex. Trevor Butler, Hadfield, Vic. Comment: 7.5A twin-core cable is not good enough for a really good highend system. You really do need thick copper cables to get the speaker cable resistance down to a fraction of an Ohm. The more copper, the better. The low resistance is needed to maintain the high damping factor of modern amplifiers but more importantly, it does have a measurable and audible effect on the upper treble response of speakers, particularly those that have a falling impedance at high frequencies. That said, it does not justify the huge cost of some speaker cables. Vintage Radio restorers should replace capacitors I am very concerned at the following statement in the Vintage Radio article in the January 2004 issue: “most of the capacitors in this design can be quite leaky without causing any harm”. In fact, there are many places in a radio circuit where a leaking capacitor will cause problems, ranging from distortion to the destruction of other components and, in some cases, fire. It was indeed unfortunate that nonleaking capacitors were not available 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 progamming 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 outs, 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. 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 May 2004 5 Mailbag: continued to the radio trade until the advent of the Philips Polyester capacitors in the late 1950s. Up until this time, paper capacitors were commonly used and these were notorious for becoming leaky. In other words, they became the equivalent of a capacitor with a resistor across it. Every old paper capacitor left in radio is a potential problem with perhaps the exception of the RF and IF cathode bypass ones. It makes good sense to replace all these old capacitors as a matter of course. The point is that this leakage increases with time. A radio may work in a fashion now but trouble can be expected in future. The modern replacements appear to be everlasting and therefore well worth the trouble. The article states it is essential to replace the audio coupling capacitor. This is certainly an important one but why only in a set without AGC? Surely a leaking capacitor in this position is going to play havoc regardless. AGC has nothing to do with it (was this a typo?). I believe a well-restored radio will be around for many years to come so we owe it to posterity to make as good a job as possible of the restoration. The following is a list of some of the points in a typical radio circuit where a leaky capacitor could cause trouble: (1). The screen bypass. Leakage here lowers the screen voltage and overloads the screen-dropping resistor which may go up in value or even burn out. (2). As above with the B+ supply to the heterodyne oscillator. (3). Most sets have a RF bypass from the B+ line to earth, usually 0.1µF or more. This item is prone to failure after restoration. A dead short here could (and has) caused the power transformer to catch on fire. (4). Leakage in AGC bypass capacitors will cause overload distortion on local stations. (5). Some sets use an audio driver such as a 6B6G with a 10MΩ grid leak resistor to develop a small amount of grid bias. The coupling capacitor here isolates the grid for DC thereby keeping the valve working in the straight por6 Silicon Chip tion of its characteristic curve (class A). Leakage in the capacitor will cause distortion. (6). As mentioned, no leakage can be tolerated in the audio coupling capacitor between the driver stage plate and grid of the output valve. A typical radio circuit will therefore have very few paper capacitors that could safely be left in the set. Most restorers simply replace them all as a matter of course. Replacing the electrolytic capacitors as a matter of course is also good insurance. I do leave the mica capacitors in place as they rarely give trouble. All resistors should also be checked and those out of tolerance replaced. Ted Baker, VK2ABW, via email. Rodney Champness replies: I agree with Ted Baker’s statement in the last sentence of his first paragraph and I agree with all of the second paragraph. However, I feel he has gone overboard in his almost blanket condemnation of paper capacitors, as many are still usable with acceptable leakage resistance. While replacing every paper capacitor may be an easy approach, the question could then be asked “How many 1930s sets had polyester capacitors?” We are taking away the authenticity of our restoration projects and no one will know what a paper capacitor looks like! I think this is important too, don’t you? I know one restorer who takes the old capacitors out of a set, removes the insides and then inserts polyester capacitors. If a restorer has the time and patience to do this, the set will look original. A set converted this way would then need to have a placard in it pointing out that “The capacitors in this set ARE POLYESTER therefore do not replace unless definitely proven faulty”! In a set without AGC the most important capacitor to have little or no leakage is the audio coupler. I did not say that I didn’t replace it in a set with AGC, as I was only talking about a set with no AGC. Previous articles show that I replace the audio coupler AND the AGC bypass capacitors as a matter of course. An audio coupler should, in my opinion, have no less than 50MΩ leakage resistance, and higher resistance in some circuits. A paper capacitor would automatically be replaced as it is unlikely to meet this requirement, when tested as I suggested on page 88 of the article. I agree with the six points Ted Baker makes on possible consequences of faulty capacitors. Now let’s look at how bad paper capacitors really are. In the critical spots that I consistently mention in my articles, no leakage below the 50MΩ mark can be tolerated. Nor would I consider using a capacitor with below 5MΩ leakage in other locations in a set, with rare exceptions. The RF bypass on the HT line needs care in assessing its suitability to remain in the set. I would measure it as I have indicated in the article. However, if the test indicates the capacitor is OK, I would then put it back into the set, turn the set on and keep an eye on it. I would then touch the capacitor after a short time (after switching off!) to see if there is any build-up of heat in it. If there is, the capacitor is removed as it will short out or explode after a little while. Screen bypass capacitors can’t be checked in the same way. In this case, measure the voltage across them and if it drops more than a few volts, the capacitor is suspect and should be given the heave-ho. After a restoration job, any set should be left running under supervision for quite a few hours to make sure ANY component (capacitor, resistor, transformer, valve, etc) that breaks down is caught before significant damage is done. Paper capacitors ARE the most troublesome components in vintage radios but some brands are better than others. In my experience, the worst were the 1940s and 1950s Ducons and UCCs. Many of the old Chanex capacitors and some of the AWA “moulded mud” capacitors are OK, despite their age. I do however, suggest checking all of them. Old scopes were built to last I recently bought two Tektronix 475 analog 200MHz oscilloscopes from Oatley Electronics for the princely siliconchip.com.au sum of $500 each plus 10% GST. I used to use these when I was serving our country in the RAAF from 19721992. I think we saw these about the later part of the 1970s. Before that we were using Tektronix 545s which contained so many valves that you could just about keep your tea hot sitting on top of it. The scope was so large that it had to be wheeled around on a trolley especially designed for the task. By contrast, the 475 was compact and fully solid-state except for the CRT. It weighed about 11kg so it was easily moved about. Looking inside these 475s, one can see the quality of manufacture, with gold plating on switch contacts and connectors everywhere. Not just a flash either but quite thick gold plating judging by the colour of it. High quality components too, for the time; no planned obsolescence that we see in equipment these days. This was a piece of test equipment made in 1974, built to last with no cost spared in the manufacture. Thirty years on there were a few faults of course; mainly noisy pots. This was rectified by injecting Servisol contact cleaner and lube into the pots concerned. The only major fault I found was in channel one’s attenuator in one of the instruments. It manifested itself as an increase in gain in the 0.5 to 5V divisions. Either the x100 attenuator circuit module was faulty or the switch contacts that brought it into use were dirty. By just touching the x100 attenuator plug-in module the fault would clear itself. I swapped this module with the one in channel two and the fault cleared. So there it was, one faulty x100 module. Not repairable according to the service manual – thank the Internet. What did techs do for information before it was born? As they say, nothing ventured, nothing gained. I very carefully prised the top off it and under a maggylamp saw a very brittle solder joint. I resoldered it with a 1mm tip soldering iron and 0.35mm 3% silver solder (I repair camcorders too), refitted the module and it all works well. It’s a pleasure to work on equipment that was built with quality in mind rather that the mostly poorly built gear that comes out of China. But that is the main-stay of consumer siliconchip.com.au electronics these days and most is just throw-away; not worth repairing. I think anyone requiring test equipment would do well seeking out the used quality equipment offered by Oatley and others, rather than buying new but inferior items. By the way, the Tektronix 475 oscilloscopes cost about $3900 (US dollars) new in 1974. I don’t think I was being paid that much a year then. Bob Scott, via email. How much light from LED driver? I have a few observations regarding the LED driver article in the March 2004 issue. I understand it’s an Oatley Electronics creation but even so, I would expect you to have had access to the finished result for long enough to test it and most importantly give some idea of its output. I tend to be cautious about time and money, not seeing the value in building something that is going to (possibly) have noticeably less performance than a “bought one”. Often, I’ve seen a kit costing close to or even more than a finished product from one of your regular advertisers. I foresee a few more LED projects in the pipeline, seeing as one of your advertisers is selling a near “equivalent” of the Luxeon Star at half the price, so it would seem timely and very useful to have some repeatable standard for rating these projects. Might I suggest as an example, a 5W or 10W festoon automotive lamp, either bare or against a 75mm round white card, to simulate the effect of a “typical” (no such thing!) interior vehicle light fitting. Or even use the genuine article. You could express the output in Lumens, candelas or simply as “usable” or “heaps brighter” or “able to read the fine-print on a politician’s promise”! Obviously SILICON CHIP is a hobby/interest magazine, so ISO standards need not apply but some repeatable, approximate idea would be appreciated. So the question remains: how bright are the 10, 20 and 30-LED versions compared to, say, a car interior lamp? Personally, I’d rather pay $50 or so for a twin compact high-efficiency fluoro from Jaycar, knowing it IS much brighter, than risking $34 (plus cost of housing) on something that might be even better still or the same. James Longmire, via email. Comment: light measurements along the lines you propose are not all that easy because we are not comparing like with like. Subjectively, the 10-LED “lamp” of the 30-LED array is about as bright as a 10W festoon lamp but the colour and light distribution are quite different, as you would expect. Electronic corrosion control debunked Thanks for writing the February 2004 Publisher’s Letter on electronic corrosion control units for automobiles. The same sceptical opinion was expressed by the late Harry Webster in a Viewpoint editorial entitled “Cars and Cathodic Protection – Watch Out For Fraudulent Gadgets” which appeared on page 8 of the June 2001 issue of Materials Performance magazine. That magazine is put out by NACE International (formerly known as the National Association of Corrosion Engineers) in Houston, Texas. Harry had been the president of NACE and was an expert on cathodic protection. Richard Garber, Portland, Oregon, USA. Valve equipment gave that warm feeling I agree with your editorial comments about the “mediocre” performance of valve amplifiers compared to today’s technology using silicon based devices. However, some of us remember the cold days of winter in far-off regions servicing radio navigation and communications type equipment, consisting of many racks of electron tubes/valves circuitry – there was never a problem staying warm. Of course, in the summer time it was a different story! There’s one other advantage of valve technology – which we all hope never comes to fruition. In the event of a “big bang” of the nuclear variety, there’ll be more valve amplifiers left standing than the semiconductor species after the EM pulse hits them. John Bond, via email. May 2004 7 Roboc Machines playing soccer? Better believe it! Since 1997, teams from across the world have been competing to build the perfect soccer-playing robots, in hope of one day developing the technology to such a level that it may compete against, and beat, the human world cup champions. 8 Silicon Chip siliconchip.com.au cup by David Perry T he challenge for roboticists is developing machines that may think and act autonomously, able to analyse sensory data and act in a meaningful way, as a human would. It was once thought that getting robots to act intelligently in the real world would be a fairly trivial step beyond computer simulations of such an environment. Several decades later, we now appreciate the complexity of the tasks that nature manages with such apparent ease. Despite millions of dollars, countless postgraduate students, academics and corporations, robots can only begin to operate intelligently within a tightly controlled environment. Any attempt to generalise a vision or learning algorithm into something mildly human-like is met with little success and a great amount of frustration. There are several factors which are making this technology evolve slower than we’d like. One is the inter-disciplinary nature of robotics and A-I (henceforth just called intelligent robotics). Robotics researchers may have a background in any number of engineering and scientific fields: computer science, cognitive sciences, mechanical, electrical or software engineering. Everything breaks – and interacts! I like to think that robotics involves Murphy’s Law cubed. The mechanics break, the electronics break and the software breaks! There are all kinds of interactions within and between these systems, challenges spanning multiple fields of engineering and sometimes aspiring to emulate the natural world. Computer-based systems can evolve because there is some standardisation amongst hardware and software. Everyone knows about C++ and has access to (and uses) PCs. But complete off-the-shelf solutions are not common in robotics. Researchers often begin by building their own mechanical platform, selecting and designing wheels, legs, motors, the chassis... Then they build motor controllers, select batteries, design controllers or work out how to use a PC or notebook computer in their design. Only a handful of companies build wheeled robots (or humanoid robots) for sale to researchers. And then they tend to be expensive and not optimal for particular research interests. In building robots, there are just too many design considerations, technology that needs to be implemented but which is not yet mature. Everybody goes off on their own research tangent and, as such, tend to develop everything from scratch, by themselves. Soccer is the equaliser One aim of the RoboCup Federation is to overcome these difficulties by providing a standard, scalable problem. That standard is the game of soccer, with a number of “leagues”. The challenge begins with playing soccer in simulation and in well lit environments with well-defined, coloured markings. The rules slowly evolve so that as the environment rules become less stringent, the robots become more robust, adaptable and, hopefully, more intelligent. Every year, the rules of each league are reviewed with aim of encouraging innovation. Field walls have been removed in some leagues and eventually colouring and lighting requirements will be relaxed. The idea is, once the ultimate challenge is fulfilled, robots will have matured to such a state that they will be feasible in everyday life. Of course, there is some way to go. The most developed robotic league in RoboCup is called the F-180 or small-size league. The ‘180’ denotes that robots may have a footprint no larger than 180cm2 – although the siliconchip.com.au May 2004 9 The F-180 league is relatively mature, games are extremely fast and teams implement complex behaviours including passing and blocking. Middle-size league Depending on the league, control can be as simple as one notebook computer – or a computer for every robot. Most work on wireless LANs. actual sizing requirements are now more complex. The game is played on a greencarpeted field about the size of a pingpong table. One goal is yellow, the other blue and the field is surrounded by a small ramped barrier which will keep a ball in play, provided it hasn’t been struck too hard. This league allows teams to use an overhead camera, connected to as much computing power as a team cares to bring with them. The computer can see the ball (an orange golf ball), the goals and every team member at all times. Local on-board vision is also allowed, although teams that use this exclusively tend to be not all that competitive. The robots themselves may have a few sensors on board (for example infrared beam sensors to detect when the robot is in possession of the ball) and some low-level control electronics. The robots are commanded by RF from the host computer which outputs the behaviour for all of the robots. The robots are in teams of five, including a goal keeper. The drive system typically entails either a differential drive (like a tank), or (more recently) omnidrive, which allows the robot to move in any direction, from any orientation. So where a robot with differential drive has to turn to the direction it wishes to travel, omnidrive can move in that direction instantaneously. It achieves this using three or four omnidirectional wheels. As well as turning like a normal wheel, these 10 Silicon Chip have rollers that allow the wheel to move in the direction of its wheel axle. By varying the speeds of the wheels, the resultant drive and slip of the rollers allows the robot to move in any direction. These robots also often include ball manipulation devices, including a kicker (usually a spring-loaded or solenoid mechanism) and ball dribbler (a rotating rubber coated bar on the front of the robot that induces a back spin on the ball, keeping it close to the robot even when travelling backwards). It would be a reasonable assumption that a computer controlled F-180 team could defeat a team of humans playing with joysticks (at least until the humans got in a great deal of practice). The F-2000, or middle-size league is less mature. Like the F-180 league, the ‘2000’ denotes that the robots may have footprints no larger than 2000cm2. Their basic physical construction is similar to that of the F180 league, only scaled up. Bigger batteries, motors and beefed-up control electronics are required to deal with this additional load. This increases cost dramatically. Their game is played on a larger field (8 x 12 metres) with a similar colouring scheme to the F-180 league. There is now only a white line at the field’s edge, so the ball can be kicked out of play easily. At each corner of the field is a coloured post. What makes this league far more challenging is the requirement for all sensors and processing to be onboard (an off-field ‘coach’ computer is permitted). The robots must now play soccer, not always having a view of the ball, team-mates, nor the goals. With the F-180 league, you could get by with one cheap desktop computer but F-2000 needs one for each robot, powered by batteries – either modified desktops, single board computers, or laptop computers. Vision consists of one or more cameras on each robot. Some use cameras aimed at a convex mirror This close-up give a good idea of the complexity involved in a soccer robot. siliconchip.com.au mounted above the robot, providing a panoramic view of the field. While this has the advantage of giving the robot the ability to see in all directions, the detail that can be viewed in a particular direction, especially at a distance, is reduced. The standard of play in this league is much lower. Given the size of the field, robots seem to move more slowly. They tend to get caught on things, run out of bounds and can’t manipulate the ball with the same agility as smaller robots. The robots lack localisation (working out where they are) to the same accuracy and thus are limited in the complexity of strategies able to be taken. Successful robots in this league tend not to be the fastest or most clever but well tuned to guarding their own goal and able manoeuvre a ball around obstacles towards the opponent’s goals. Humanoid league The challenge takes a final step up in the humanoid league. These will be the robots that will hopefully face humans in a full-scale match in 46 years (2050 is the RoboCup organisation’s target date). At the moment, however, they’re quite primitive. Robots can be in a number of size classes, some over 2m tall. The tasks they must complete include subsets of skills needed for an actual game (walking, penalty kicks, standing on one leg) and a one-on-one competition. These robots can be enormously expensive to build. While wheeled robots need only a few actuators, humanoids can have dozens. The power requirements are considerable, as are the computational requirements (humanoid robots require very high speed control systems that can deal with balancing the robot in real time). The development of humanoid robots is a story in itself. Honda spent decades and hundreds of millions of dollars developing their humanoid robots, ASIMO being the latest. These intensely engineered robots can make the whole task seem easy. They’re often described as looking and walking like men in space suits. Some robots in this league do have this level of agility and apply it in playing soccer. Game play at its best, however, is still very slow and delicate. The robot’s foremost concern is siliconchip.com.au This shows the long and the short of it: some of the humanoid-class robots stand 2m tall and cost a fortune to build . . . staying upright so any attempt to kick or block a soccer ball comes second to maintaining balance. Other leagues There are four other leagues in the competition which complement the F-180, F-2000 and humanoid competitions. The first of which is a simulation league, where competitors create teams entirely in software. Unhindered by hardware, they can focus on creating intelligent agents which are able to perceive environmental data provided by the ‘soccer server’ and formulate the necessary actions to be taken. Software teams are played off against each other in the “virtual arena” of the soccer server and the game is shown on large screens throughout the competition. The rescue league diverts completely from the game of soccer, aiming to provide an immediate practical application. There are two components to this league. The first is a simulation league where the behaviour of emergency responses (for example fire fighters) is simulated on a large scale. It is hoped this research will provide data to assist emergency services in best distributing resources in disaster scenarios. The second consists of real rescue robots that may be sent into a disaster zone that is either inaccessible or too dangerous for human rescuers to reach. The robots are varied, some having on-board sensors and intelligence. Others are tele-operated, either by radio or a cable dragged behind. In competition robots are sent through a . . . on the other hand, there are little fellas in the RoboCup competition too. May 2004 11 They’re cute to watch: the four-legged league is based on Sony’s “AIBO” robot dogs and creates a level hardware playing field. course of unknown configuration, and must avoid obstacles to find and map the location of potential survivors. The ‘survivors’ are plastic mannequins which may have actuated limbs that shake, or heating pads to give the impression of a warm, alive body. The robots detect the survivors through vision, thermal detection or motion sensing. Similar robots were deployed at the World Trade Centre to search through the debris for survivors, unfortunately without success. The scoring is dependent on the quality of data acquired and the amount of human assistance. In the future, the league will be expanded so that robots can perform additional rescue functions, such as administering first aid or reinforcing unstable structures. Perhaps the cutest robots belong to the four-legged league. Sony AIBO robotic dogs are programmed to play soccer, on a field similar to that of the F-180 league. Sony is a major sponsor of RoboCup so the league is good publicity. But the fixed hardware also forces teams to deal entirely in software. In some ways it creates a fairer competition, as teams can’t simply buy more powerful motors or computers to defeat the competition. Every effort is made to extract maximum performance from the fourlegged dogs. Extensive fine tuning of the walking gait ensures maximum speed and the robots often walk with their heads low to the ground and legs spread out to block or intercept the ball. The Sony AIBO ERS-210A robot, 12 Silicon Chip one of the newer versions, has 20 degrees of freedom (DOF) throughout its four legs, head, ears and tail. The computing power on-board is roughly equivalent to a small PC or PDA, with its 64 bit RISC processor running at 384MHz. The robots typically make use of wireless networking, as with other leagues, to communicate and also take game start/stop instructions. The legged league may be cute and fun to watch but the game-play is still of relatively low quality. Despite the valiant efforts of their programmers, the robot’s hardware is limited. The single on-board CMOS camera has limited resolution (176x144), the motors have limited torque and speed, and the computer has limited power and memory. The situation will improve, with the latest version of AIBO, the ERS-7. This robot should make its debut at RoboCup 2004. It may well be that the league advances along with Sony’s periodical release of newer, more advanced robots. As with the main competition there are several leagues, including soccer, rescue and dance, each with set age groups. The soccer league is either 1-on-1 or 2-on-2. Several changes are made from the grown-up version to simplify the technology required to compete. For example, the field has a monochrome gradient, rather than green carpet. By reading the field with a light sensor, a robot can judge its position along the length of the field. The goals are black at one end, and white at the other, also allowing them to be found with a simple light sensor rather than an expensive camera. There are 140mm high walls around the edge of the field. Finally, the ball itself is a clear plastic shell with several infrared LEDs inside. Thus the ball can be found by scanning for the unmodulated infrared light emitted, using a filtered light sensor like a photodiode. The junior rescue league is essentially a scaled down version of the parent. The course is smaller and has less obstacles. There is a line that a robot may follow that will lead it through all the various sections of the course, without the need for complex navigation. The survivors are denoted by either a green or silver patch on the floor of the course. These colours can be differentiated with a light sensor, aimed at the floor. In the dance league, aimed at younger students, robots are constructed and Who’s playing – and paying? The majority of participants in RoboCup are universities, with a small number of companies also putting forth teams. The costs of parts, travel and registration don’t leave much room for the hobbyist. However there is a concession in the form of RoboCup Junior, a branch of the competition for primary and secondary school students. Where RoboCup focuses on fostering research, RoboCup Junior is about encouraging education in science and technology. In every RoboCup competition arena you’ll find a “pit” area set up for last minute tweaks and of course repairs. siliconchip.com.au programmed to dance to a song for up to two minutes. Some have clever motorised limbs and timing, others are simply dressed up. Robots were at first solely constructed using Lego Mindstorms. These Lego systems have sensors and controllers well suited to the junior soccer, rescue and dance leagues. Drive systems are also quite easy to construct. Advanced teams now use more customised hardware, including microcontroller boards and ultrasonic sensors. Melbourne Uni team I was involved with the University of Melbourne mid-size team, within the Department of Electrical and Electronic Engineering. We competed at RoboCup2003 in Padua, Italy. It was the first year we had competed. This, combined with our extreme under-preparedness, proved extremely challenging. Due to delays in manufacture, much of the hardware was untested, up to the point that we were assembling things for the first time, just days prior to the competition (even on the plane to Italy!). The MU-Wallabies, as we were known, had several design criteria in mind. One was the need for small, highly manoeuvrable robots. Also, an omnidirectional kicking device was designed. It consisted of a ‘leg’ which was able to be rotated about the robot’s circular body. Unfortunately, a number of problems arose. In order to fit in a kicking device that protruded from the robot’s body, the body had to be quite small. This required that the wheels (we used differential drive) be close together and that the laptop computer used to control the robot be mounted vertically. Ooops! The first question we were asked about our robots, after being asked whether they could participate in “Robot Wars” (instead of Robocup!), is whether they will tip over. We were hoping software algorithms would prevent this from happening, although sometimes collisions or malfunctions would cause a robot to turn too tightly and fall over in competition – much to the opposing teams delight. Also, the aim of having fast robots has yet to be fulfilled. The cheap motors and gearing used failed to perform to expectation and we’ve been forced siliconchip.com.au to move to much more expensive precision Swiss-made motors with planetary gearboxes. Our entire drive system, despite requiring custom CNC machined parts, only cost around $1500 per robot. The new motors alone will cost $1200 per robot. Additional problems included faulty wiring and overheated battery packs. All of these things were quite preventable but we simply lacked the time to catch all the bugs. The laptops run a Slackware Linux distribution, and the C++ control code is compiled with GNU (open source) tools. Inexpensive Logitech webcams are used for vision, through the USB port. They run on the Video4Linux drivers that are compatible with the Philips webcam chipset. Images of 320 x 240 pixels are captured and processed at a speed of about 10 frames per second. This maximum speed is a limitation of the webcam, and not the software or laptop. The software classifies regions in the image based on colour and makes a determination as to what the corresponding object is. It needs to be calibrated, as colours can vary depending on lighting conditions. The vision software provides polar coordinates (angle and distance) for each object in view on the field. The next step in processing is either acting directly on this data, or using it for localisation. This process determines where a robot is in relation to the entire field. For instance, it may output a cartesian x-y co-ordinate, where the origin is in the centre circle. Through the 802.11b wireless network, robots can collate this information and build a detailed model of where everything is on the field. Artificial intelligence software takes this information about the environment and works out what actions to take. In 2003, this software was extremely simple. That said, it did work surprisingly well and our main source of problems was hardware breakdown. Australia is a strong, competitive participant in the RoboCup competition. Other institutions competing include the University of Queensland, University of NSW, University of Newcastle and University of Technology, Sydney. In 2003, researchers from Australia took out both the Engineering Challenge Awards. rUNSWift from the University of New South Wales took first place in the Sony legged league, with the Nubots from the University of Newcastle coming in third. One of the most exciting matches saw the RoboRoos of the University of Queensland facing BigRed from Cornell University in the US, in the F-180 final. Cornell has enormous financial and human backing, including Microsoft and NASA, and they have dozens of students and staff assisting. Despite this, they were defeated in an earlier round-robin match by the University of Queensland. Unfortunately, Cornell managed a 1-0 defeat of the RoboRoos in the final, with the match having gone into overtime. RoboCup 2004 is to be held in Lisbon, Portugal, from June 27 to July 5. If you would perhaps like to get involved, or just watch these robots in action without the expense of overseas travel, there may be a local alternative. RoboCup Junior has state and national competitions every year. For the more ambitious, the University of Melbourne mid-size RoboCup team is aiming to set up a wider robotics competition later this year that will SC be open to all. Weblinks: www.robocup.org/ – RoboCup Official website www.robocup2004.pt/ – RoboCup2004 ww.robocupjunior.org.au/ – RoboCup Junior Australia robocup.ee.mu.oz.au/ – University of Melbourne mid-size team May 2004 13 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 You don’t need fancy gear to check out audio amplifiers: just an input signal from a PC sound card, a multimeter, a loudspeaker, a wirewound resistor and a dummy load made from some electric jug elements suspended in water. You don’t need a bench full of expensive equipment to test audio amplifiers. Here’s how to go about it using gear that’s readily to hand. By JULIAN EDGAR Amplifier Testing without high-cost gear I F YOU’RE ANYTHING like me, you can’t resist picking up a bargain – especially when it’s a cheap piece of electronics that someone in their, er, wisdom has decided no longer has the right fashion look. Take audio hifi amplifiers, for example. Visit (in declining order of salubriousness) secondhand stores, garage sales, roadside rubbish collections and the tip and you’ll find a host of amplifiers that are available at ridiculous cost (as in, ridiculously low . . .). Consider, for example, the Rotel 712 integrated stereo amplifier shown 18 Silicon Chip on these pages. It cost me just $8.00. Yes, that’s right . . . eight bucks. What was wrong with it, you ask? Answer: nothing. Similar bargains can be had in lots of places. Recently, I bought a Rotel (yep, I like that brand) RX-203 stereo receiver for . . . wait for it . . . $3. So what was wrong with that one? Well, I haven’t tested it yet but I’ll wager that it also works fine. Talking about testing, until recently I thought that any meaningful testing of an amplifier needed stuff like oscilloscopes, standalone frequency generators and specialised audio test gear that I didn’t even know about. But then, through the advice of three learned men, I saw the light – the amplifier “test light”, so to speak. Those three wise men advised me that all I needed was a digital multimeter, my trusty PC, a few cheap resistors . . . and a jug element! A jug element? It all sounded so crazy that it might just work. But do the figures really matter? After all, the reason that you buy an audio amplifier is to listen to it. The answer is yes, especially if you’ve siliconchip.com.au Fig.1: all the tests require a set-up like this. The PC’s sound card output is connected to the amplifier’s input, while the amplifier’s output drives both the dummy load (the jug elements immersed in water) and the monitoring speaker (via a 150Ω resistor). The multimeter is used to measure the AC voltage at the amplifier’s output. heard the distorted sound that some appear people to like. What’s required The first things that you need for amplifier testing are your ears – both to assess the purity of a quiet test tone and also to listen for any background noise that might exist when there shouldn’t be any. You’ll also need a decent digital multimeter. These days “decent” applies down to multimeters costing from about $60, so almost any recent meter will do. It also helps if it can measure frequency in addition to the usual AC volts and resistance. However, that’s not vital – it’s just a good check. A cable that connects your PC’s sound card output to the amplifier inputs will also be needed. Typically, this will be a cable with a 3mm stereo plug at one end and two RCA plugs at the other. On the output side of the amplifier, you’ll need to connect a monitoring speaker. This will only ever be used at low volumes (no test tones will destroy it), so it can be one of your normal hifi speakers. To reduce the power into the speaker (so that you won’t be deafened), you’ll need to connect a 150Ω 5W wirewound resistor in series with it. That will set you back about 30 cents – or nothing if you can salvage one from your junkbox (I got one from an old photocopier). And now we come to the jug elesiliconchip.com.au ment, or elements. Yes, you’ll need one or two electric jug elements (ie, the 240V sort that you can buy at any supermarket) and a Pyrex or hightemperature glass bowl that you can fill with water before suspending the elements within it. If you haven’t already guessed, this is our amplifier load – and a beauty it is, too. Making the load Turning the jug elements into the load is easy. If you use two (as I did), gradually unwind turns of wire from each element until the remainder left on each ceramic former has a resistance of 16Ω, as measured with your multimeter. Then, when you wire the modified elements in parallel, you’ll have a very high power load with a total resistance of 8Ω. Alternatively, you can make each element 4Ω and then wire them in series for an 8Ω load. It really doesn’t matter how you do it – you just want lots of windings and a resistance that matches the load the amplifier expects to see. This secondhand amplifier – bought for just $8.00 – was the guinea pig for much of the testing described here. Using just simple tools and techniques, its power output, frequency response and signal-to-noise ratio were all measured, along with the response of its tone controls. May 2004 19 The amplifier test load is formed by two slightly modified electric jug elements suspended in a jug of cooling water. This load can sink very large power outputs – if the water starts getting hot, simply swap it for some cold water. You can also make 2Ω and 4Ω loads, just by modifying the above procedure. Next, place the elements in that bowl of water and then use heavygauge wire to connect the jug elements together and to the amplifier. Warning: if you are testing a highpower amplifier, this water can become hot enough to burn. Ensure that small children, pets, local religious proselytisers and the like cannot come in contact with it. Generating the test tones To generate pure sinewave test tones, you’ll need to download some frequency generator software off the web. This is available either free of charge or with a 30-day free trial period. We used PAS Products Frequency Generator version 2.6 (from www.pasproducts.com) but there are plenty of other programs around – a web search will soon find them. Practice playing with the generator while monitoring the sound through your normal PC speakers until you are able to do two things: (1) generate sinewave signals over a 20Hz to 20kHz (20,000Hz) range; and (2) vary the volume level. The latter requirement is important – some frequency generators make it difficult to vary the 20 Silicon Chip amplitude (volume) of the test tones and so you should check that this function exists. Measuring power This one’s really exciting – everyone knows about amplifier power and being able to measure the output with your own eyes, hands and ears is great fun. Here’s how you do it: (1). Ensure that the load is covered by water, then connect it to one channel of the amplifier. (2). Wire the monitoring speaker in parallel with the load – ie, connect it to the same channel. Don’t forget that you need to install a 150Ω 5W resistor in series with the feed to this speaker – see Fig.1. (3). Set your multimeter to “VOLTS AC” and connect it across the same channel. (4). Connect the line-level output from the sound card to the corresponding input of the amplifier. (5). Start the frequency generator software on your PC and select a frequency of 1000Hz. (6). Set the volume control on the frequency generator software to give an amplifier input voltage of 1V (you can measure this at the input to the amplifier). If the sound card’s output won’t go that high, set it to a lower value that you carefully note. Fig.1 shows the complete test setup. When you turn up the amplifier’s volume control (you did remember to switch it on?), you should hear a faint 1000Hz test tone coming from the speaker. At the same time, there should also be an AC voltage level on the multimeter. If everything is working as it should, turn up the amplifier volume, listening intently to the test sound and watching the changing figures on the multimeter. When the volume reaches a certain point – called “clipping” – the sound from the speaker will suddenly and clearly distort. Take note of the multimeter reading and then quickly turn the volume back down. On my $8.00 Rotel unit, the lefthand channel yielded a result of 19.6V before clipping. So how do we turn this into a maximum power figure? It’s easy – just square the number (ie, multiply it by itself) and then divide that by the resistance of your dummy load. The formula is: P = V2/R. In this case, we have 19.6 x 19.6 ÷ 8.5 = 45 watts (45W). I then repeated the test for the other channel and got a figure of 48W. Not bad, eh? My $8.00 amplifier has a bit of punch! Checking frequency response A 150Ω 5W wirewound resistor is wired in series with the loudspeaker so that the test tones can be monitored at full amplifier power. This resistor can be bought off-the-shelf for about 30c or better still, salvaged for nothing from discarded equipment. Now you might be saying that it’s great that this amplifier has 45-odd watts per channel, but that’s only at 1000Hz. What about over the rest of the frequency range? This introduces the idea of frequency response – just how flat is the response of the amplifier across its frequency range? Testing this is again very easy and siliconchip.com.au the set-up is the same as shown in Fig.1. Leave everything in place as it was for the previous test but wind the wick down to about “2” or “3” on the volume dial (ie, adjust it to what normally would be a quiet listening level). Now decrease the test tone frequency to 20Hz (you will no longer be able to hear it from your speaker – the frequency is too low). Make sure that all the tone controls are set to flat (zero adjustment) and switch off the loudness button. Next, measure the input voltage to the amplifier – it should be the same as it was for the previous test – ie, 1V (or your nominated figure). If the input voltage has changed, adjust the output of the frequency generator until it is again 1V (or the nominated test figure), then measure the output voltage of the amplifier and note this value. Next, change the input frequency to 100Hz and adjust the generator until the input signal is the same as for the previous measurement. As before, measure the output voltage from the amplifier and note this value. Keep doing this right through the frequency range, up to 20,000Hz. Of course, you don’t need to do the measurements all in small increments. Table 1 shows the results of this testing on the Rotel amplifier. As you can see, with a constant input voltage, the highest output from the right channel was 2.2V while the lowest was 2.1V. So it doesn’t vary much, does it? But how do we express this variation in that unit beloved of audio engineers – decibels or dB? Again, it’s easy: simply divide the highest figure by the lowest, take the logarithm of the result, then multiply by 20. So, from the table of data: [log (2.2/2.1)] x 20 = 0.4dB So between 20 and 20,000Hz the biggest variation away from a ruler flat response for this channel is just 0.4dB. The other channel measured a little worse at 0.5dB. Those are very good specifications for an amplifier – those eight dollars are looking better and better all the time! Signal-to-noise ratio The signal-to-noise ratio is a measure of how quiet an amplifier by itself is: for example, when all the sound stops, you shouldn’t be able to hear anything – no hiss and no hum. Well, not because of the amplifier, anyway. siliconchip.com.au Fig.2: this audio frequency generator software is available for a 30-day free trial period via a web download. Just about any frequency generator software is suitable for the amplifier testing procedure described in this article. Table 1: Frequency Response Measurements Frequency 20Hz 100Hz 1kHz 5kHz 10kHz 15kHz 20kHz R-Channel Output 2.17V 2.15V 2.20V 2.10V 2.10V 2.12V 2.10V L-Channel Output 2.23V 2.15V 2.12V 2.14V 2.18V 2.10V 2.15V This table shows the output voltages measured for both the left and right channels at seven different input frequencies. As can be seen, the left channel of the old Rotel amplifier has a slightly wider variation than the right channel. However, simple calculations (see text) show that even this varies by only about 0.5dB. Note: input signal voltage held at a constant 1V. Remember how when we tested the maximum power output on the Rotel, we achieved a maximum output before clipping of 19.6V? That’s one of the figures we need for this test. The other is gathered by again measuring the voltage output with the volume control wound almost fully up but this time with zero signal input. However, if we simply pull the signal input lead out of the amplifier, it’s likely that electrical noise will be picked up from the surroundings. To overcome this, we wire a 1kΩ resistor across the input. As well as preventing noise pickup, this also keeps the amplifier “happy” as it’s seeing some input resistance. Again the dummy load, speaker and multimeter can be left connected as we had them before. Now wind up the volume control to the level at which clipping previously occurred Table 2: Bass Control Response Frequency 20Hz 50Hz 100Hz Bass Control Max. 11.1V 9.9V Bass Control Min. 0.40V 0.48V 0.67V 7.3V As shown here, the Rotel amplifier’s bass control has its maximum effect at just 20Hz. These are the “raw” voltage outputs when the bass control is turned and some simple calculations show the adjustment range to be about ±14dB. Note: input signal held at 1V; output signal is 2.16V with control “flat” (ie, centred). (eg “8” on the knob) and read the noinput-signal output voltage. It will be very low. In the case of the Rotel, it was 2.6mV. So at full power, the output was 19.6V (that’s 19,600mV) while with no input, the output is 2.6mV at the May 2004 21 Another Secondhand “Bargain” Amplifier computer fans constantly humming away in the background – I can never hear any noise from the it, anyway. (Well, that’s my excuse!) And that brings us to another simple testing technique. Connect the amplifier to its normal speakers (no resistor needed) and make sure that there is no input signal. That done, turn the volume right up and listen intently to the speakers. The more noise that you can then hear, the poorer the signal-tonoise ratio of the amplifier. Bass & treble controls It was another “cheapy” buy although not in the same class as the Rotel covered in the main text. I bought this Bose professional amplifier by tender (so no extensive testing was allowed prior to purchase) for just $480. That’s pretty good when the new price is US$2000 and the thing can develop no less than a claimed 450W per channel into 8Ω loads! Unfortunately, once I’d got it home, I found that my new purchase wouldn’t develop any watts into any channels. Instead, it just blew the circuit breaker on the external power board. Inside the case, the transformer was simultaneously getting hot and it proved very expensive to replace. The replacement fixed the problem and I was ready to do some testing. So how much power output did it deliver? Well, with one channel driven, try 560W into an 8.5Ω load! And that’s with no apparent clipping (this amplifier incorporates internal soft clipping circuitry). Its signal-to-noise ratio wasn’t as impressive though and measured just 88dB – way below the best of SILICON CHIP’s designs. same volume control position. To turn this into the signal-to-noise ratio, we do the same sort of calculation as for frequency response, ie: [log (19,600/2.6)] x 20 = 77.5dB Now a 77.5dB signal-to-noise ratio isn’t wonderful – in fact, one of the three wise men told me that it’s about par for the course for FM radio. But where I’m using this amplifier – with Important Points To Note (1) The frequency response tests in this article assume that the digital multimeter has a frequency response up to at least 20kHz. Many DMMs are not this good and may have a frequency not much in excess of 1kHz. Such meters can be used for the power test at 1kHz but not the frequency response or treble control checks. (2) When doing power output tests on valve stereo amplifiers, both channel outputs must have dummy loads. Operating a valve amplifier without a load may cause serious damage. (3) The power tests in this article are equivalent to the continuous (RMS) power output of an amplifier, even though 22 Silicon Chip they are carried out for a short duration. Running an amplifier continuously under these conditions may cause damage. (4) If you want to experiment further with Internet software for audio testing, including having your PC operate as an audio oscilloscope, refer to “Digital Instrumentation Software For Your PC” and “Sound Card Interface For PC Test Instruments”. Both these articles were published in the August 2002 issue of SILICON CHIP. The printed edition of this magazine is available for $8.80 including postage within Australia or on-line for the same price from siliconchip.com.au Measuring the action of the bass and treble controls is very similar to measuring the frequency response – except this time you’re the one causing the change in the response. To begin, set the amplifier test system up as for testing frequency response – ie, dummy load, monitoring speaker, constant input signal level, and your multimeter in parallel with the load and speaker. Most bass and treble controls are centred around 100Hz and 5000Hz respectively, so start testing with those frequencies. As an example, let’s look at the action of the bass control. With a 100Hz input signal (say at 1V level), the output might be 2.16V with the bass control flat, 7.3V with it at maximum, and 0.67V with it at minimum. Note these figures, then repeat the procedure for 50Hz and 20Hz input signals. Table 2 shows the results for my Rotel amplifier. This reveals that the maximum effect of the bass control is at 20Hz – an unusually low frequency. It also shows that it can boost the signal output from a “flat” 2.16V level to 11.1V, or reduce it to just 0.4V. Expressing these as dB figures uses the same old equation: [log (11.1/2.16)] x 20 = 14dB gain Similarly, the bass cut was almost symmetrical at 14-15dB, while the treble (centred around a high 15kHz) proved to be ±12dB. Conclusion It’s possible to gain a lot of information about the performance of an audio amplifier with very little effort and just a few basic test tools. Give it a go some time – you’ll quickly find out just how good (or bad) that bargain really is. 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The component video outputs are the ones to use. But what if your TV can only accept “RGB” video signals? This easy-to-build converter solves the problem, with no discernible picture degradation. T By JIM ROWE HE PICTURE AND sound quality available from DVD video discs is streets ahead of what’s available from VHS tapes. That’s no doubt why sales of DVD players, widescreen TVs and surround sound systems have rocketed ahead in the last couple of years. DVDs have also 24 Silicon Chip generated tremendous interest in setting up home theatres, so enthusiasts can watch movies at home with a presentation almost as good as that in their local cinema. At the same time, the very high picture and sound quality available from the best movie DVDs has raised consumer expectations. And it has motivated enthusiasts to find out how they can achieve the best possible results from their home theatre set-ups. For example, most people are now aware that the highest picture quality from a DVD can be achieved only by using a player fitted with “component video” outputs, connected in turn to the corresponding inputs of a widescreen TV or video projector. This is because the video is actually recorded on DVDs in digital component format, so component video output signals have undergone less processing than those from S-video or composite video outputs. As a result, component video signals provide cleaner and sharper pictures than the other signal formats. However, some widescreen TVs (particularly those of European siliconchip.com.au Fig.1: block diagram of the Component Video To RGB Converter. IC1b is used to produce the G-Y colour difference signal, while IC2a, IC3a & IC4a produce inverted RGB signals which are then buffered and fed to the outputs. origin) and some projectors don’t have component video inputs. Instead, they may be fitted with “RGB” (red, green, blue) video inputs, made either via RCA connectors or a European-style SCART connector – these in addition to the usual composite video and Svideo inputs And that’s where problems can arise – RGB inputs are not compatible with component video signals (and most DVD players don’t have RGB outputs). This means that you need a converter box to change the signal format if you want to drive your TV’s RGB inputs from the component video outputs on your DVD player. And that’s exactly what this lowcost project is designed to do. As shown in the photos, it’s housed in a small instrument case and has three RCA sockets on the front panel to accept component video signals from a DVD player. The circuitry inside then processes these signals to produce the corresponding RGB video and sync signals, which are provided via four RCA sockets on the rear panel. These output signals can then be fed to the RGB video inputs of a TV set or video projector, either via RCA-to-RCA siliconchip.com.au cables or via a SCART adaptor cable if necessary. The complete converter is easy to build and runs from a 9V AC plugpack supply, drawing less than 150mA (1.3W). How it works To understand how the converter works, you need to know that the component video format used on DVDs consists of three video signals or “components”. These are the “Y” or luminance signal and two other signals called “R-Y” (or “Cr” or “Pr”) and “B- Y” (or “Cb” or “Pb”). The Y signal is basically the high-bandwidth black and white picture information, while the R-Y and B-Y signals are described as the colour difference signals (these have a lower bandwidth than the Y signal). As the R-Y and B-Y labels suggest, these two colour difference signals actually correspond to the red (R) and blue (B) colour signals from the colour TV camera (or film scanner) that’s used to produce the video signals in the first place, but with the Y luminance signal subtracted from them. The RGB output signals are accessible via RCA sockets at the rear of the unit, along with a composite sync output signal (see text). Also accessible from the rear is the power socket. May 2004 25 Parts List 1 PC board, code 02105041, 117 x 102mm (double sided) 1 plastic instrument case, 140 x 110 x 35mm 7 RCA sockets, 90° PC-mount (2 red, 2 black, 1 yellow, 1 green, 1 white) 1 2.5mm concentric power socket, PC-mount 8 4G x 6mm self-tapping screws 2 M3 x 6mm machine screws with nuts & lock washers 4 stick-on rubber feet Semiconductors 4 MAX4451ESA dual wideband op amps, SOIC-8 (IC1-IC4) 1 LM1881 video sync separator (IC5) 1 7805 +5V regulator (REG1) 1 7905 -5V regulator (REG2) 1 3mm green LED (LED1) 2 1N4004 diodes (D1,D2) Capacitors 2 2200µF 16V or 25V RB electrolytic 2 100µF 10V RB electrolytic 2 10µF tantalum 2 2.2µF tantalum 9 100nF multilayer monolithic 2 100nF MKT polyester 1 470pF disc ceramic Resistors (0.25W, 1%) 1 680kΩ 19 510Ω 1 7.5kΩ 1 470Ω 1 4.3kΩ 1 180Ω 1 3.6kΩ 1 100Ω 1 2.7kΩ 1 91Ω 1 1kΩ 4 75Ω 1 620Ω 1 24Ω If you’re wondering where the green or “G” colour signal is hiding, it’s inside the Y signal. That’s because the Y signal is itself produced by processing or “matrixing” the three original colour camera signals, according to this standard formula: (1). Y = 0.3R + 0.59G + 0.11B So a more expanded way of expressing the R-Y and B-Y signals is: (2). R-Y = 0.7R - 0.59G - 0.11B (3). B-Y = -0.3R - 0.59G + 0.89B Now since the two colour difference component signals simply consist of the Y “mixture” signal subtracted from the original R and B signals, it’s not very difficult to convert them back 26 Silicon Chip again. All that needs to be done is to add the Y signal to them again; ie: (4). R-Y + Y = R (5). B-Y + Y = B It’s slightly harder to restore the original green signal, because this involves two steps. First we have to recreate the G-Y signal and this is done by dematrixing the R-Y and B-Y signals according to this expression: (6). -(0.51(R-Y) + 0.186(B-Y)) = G-Y You can check this out for yourself by expanding the lefthand side using the full expressions for R-Y and B-Y given in equations (2) and (3). The G signal can then be recovered by adding in the Y signal, as follows: (7). G-Y + Y = G Block diagram Just how we do all of this is shown in the block diagram of Fig.1. The first step is to reconstruct the G-Y signal, by combining 0.51 of the R-Y signal with 0.186 of the B-Y signal. This is done using a wideband inverting adder stage based on IC1b. We now have all three colour difference signals (the other two are fed in directly from the DVD player), so these are then added to the Y luminance signal using inverting adder stages IC4a, IC3a and IC2a. The outputs of these stages are thus inverted versions of the R, G and B colour signals, so all we have to do after that is pass each one through an inverting output buffer. These output buffers – IC4b, IC3b & IC2b – then drive 75Ω video cables and the 75Ω inputs of a TV receiver (or video projector). Note that each output buffer stage has a 75Ω “back termination” resistor in series with the output. Because of this, each buffer is given a voltage gain of two (+6dB), to compensate for the 6dB loss that is introduced by these resistors. But why does the converter also have a sync separator stage using IC5? Well, we’ve included this because there’s some variation in the way TVs and video projectors with RGB inputs handle the video sync signal. Some extract the sync signal from the green (G) video signal, a technique known as “sync out of green”, while others expect to receive the video sync signal via a separate composite sync (CS) input line. The green output from the converter automatically contains the sync signals (as do the red and blue signals), so there’s no trouble driving a set with “sync out of green” circuitry. However, so that you can also drive a set which needs separate composite sync, we’ve included the sync separator as well. This is derived by first feeding the Y signal to a low-pass filter to remove the colour information. The signal is then fed to a sync separator stage based on IC5 and the CS output from this stage then fed through unity gain buffer stage IC1a, so that the sync signal can be fed along a 75Ω cable. Circuit details If you’ve followed the description so far from the block diagram, you shouldn’t have any problems following the full circuit – see Fig.2. As shown, all the video adder and output buffer stages are designed around MAX4451ESA dual wideband (210MHz) op amp ICs from Maxim Integrated Products. Despite its low cost, the MAX4451 is a very impressive device. Each of its two op amps has a -3dB bandwidth of 210MHz, a gain flat to 55MHz within 0.1dB, and an output slew rate of 485V/µs. This is in a device which comes in an 8-lead SOIC package, and draws a quiescent current of just 6.5mA per amplifier from a ±5V supply. In short, it is ideal for this type of video processing circuit. The nominal resistor value shown as R1 in the block diagram becomes 510Ω in the full circuit, so this is the value of most of the resistors in the converter. The main resistors with different values are the input resistors for IC1b – which are values chosen to give the correct fractions of R-Y and B-Y to reconstruct G-Y – and the load resistors for the R-Y, Y and B-Y inputs. These may seem to have rather strange values but they’ve been chosen to bring each input resistance as close as possible to 75Ω (for good cable termination) while allowing for the inputs of the various adder circuits. The back termination resistors for each of the four converter outputs are of course 75Ω, as shown in the block diagram. Note that although sync output buffer IC1a is a unity gain “voltage follower”, the MAX4451 requires a 24Ω resistor in series with the link back to the negative input to ensure stability. The low-pass filter that’s used to remove the colour information (prior to the sync separator stage) consists of siliconchip.com.au siliconchip.com.au May 2004 27 Fig.2: the complete circuit if the Component Video To RGB Converter. The video adder and output buffer stages are all based on MAX4451 dual wideband op amps, while an LM1881 sync separator is used to provide the sync output (via buffer IC1a). from +5V and -5V, while the LM1881 also runs from +5V. This allows the converter to be operated from a very simple power supply. As shown, this supply uses an external 9V AC plugpack and this feeds two half-wave rectifiers (D1 & D2) and two 2200µF capacitors to give ±13.5V DC rails. Regulators REG1 and REG2 are then used to provide stable ±5V rails for the converter circuitry. In addition, the +5V rail is used to power the green pilot LED via a 470Ω current-limiting resistor. Construction All the video converter circuitry is built on a double-sided PC board coded 02105041 and measuring 117 x 102mm. This in turn is housed in a small instrument case measuring 140 x 110 x 35mm, to produce a very compact and neat unit. There’s no off-board wiring at all, because all the input and output connectors are mounted directly on the PC board along the front and rear edges. As a result, they are all accessed through holes in the front and rear panels, when the case is assembled. Note, however, that although the PC board is double-sided, the board supplied in kits will probably not have plated-through holes (unless one of the kit suppliers decides to provide it in this more expensive form). As a result, you’ll need to solder many of the component leads to the copper on the top of the board, as well as underneath. You’ll also need to solder short lengths of tinned copper wire (such as resistor lead offcuts) through a small NOTE: RED DOTS INDICATE WHERE COMPONENT LEADS AND PIN-THROUGHS ARE SOLDERED TO BOTH THE TOP AND BOTTOM COPPER Fig.3: install the parts on the top of the PC board as shown here. The red dots indicate where component leads and “pin-throughs” have to be soldered on both sides of the board. a 620Ω resistor and 470pF capacitor. From there, the signal is fed to pin 2 of the sync separator (IC5) via a 100nF capacitor. A standard LM1881 device is used for the sync separator and its output at pin 1 is fed to pin 3 of the unity-gain output buffer (IC1a). Power supply All the MAX4451 amplifiers run Table 1: Resistor Colour Codes o o o o o o o o o o o o o o o No. 1 1 1 1 1 1 1 19 1 1 1 1 4 1 28 Silicon Chip Value 680kΩ 7.5kΩ 4.3kΩ 3.6kΩ 2.7kΩ 1kΩ 620Ω 510Ω 470Ω 180Ω 100Ω 91Ω 75Ω 24Ω 4-Band Code (1%) blue grey yellow brown violet green red brown yellow orange red brown orange blue red brown red violet red brown brown black red brown blue red brown brown green brown brown brown yellow violet brown brown brown grey brown brown brown black brown brown white brown black brown violet green black brown red yellow black brown 5-Band Code (1%) blue grey black orange brown violet green black brown brown yellow orange black brown brown orange blue black brown brown red violet black brown brown brown black black brown brown blue red black black brown green brown black black brown yellow violet black black brown brown grey black black brown brown black black black brown white brown black gold brown violet green black gold brown red yellow black gold brown siliconchip.com.au Will It Work Backwards? Can this circuit be made to work backwards – ie, convert RGB video to component video? Unfortunately, the answer to this question is “no”. RGB to component video conversion requires a PAL encoding circuit, which is much more complicated than the relatively simple unit described here. number of “via” holes, to make connections between some of the top and bottom tracks. These points are all indicated on the “top-side” PC board overlay diagram (Fig.3) with red dots. As shown in Fig.3, most of the components fit on the top of the board in the usual way. The only exceptions are the four MAX4451ESA broadband op amps (IC1-IC4), which are in surfacemount SOIC packages and must be mounted on the bottom of the board. Begin the board assembly by fitting the short wire links which form “vias” between some of the top and bottom copper tracks. There are only five of these, all in the central area of the board around IC5. Fitting these first will ensure you don’t forget them! Next, fit the resistors, making sure you solder their “earthy” leads on both sides of the board where indicated. That done, install the RCA sockets and the 9V AC input socket, using a small drill to enlarge their mounting holes if necessary. The small monolithic and MKT capacitors, plus the solitary 470pF disc ceramic, can go in next, followed by the four TAG tantalum capacitors and the larger electrolytics. Make sure that the polarised components are all orientated correctly, as shown on Fig.3, and don’t forget to solder their leads to the top copper as well where this is indicated. Next, fit the two diodes in the power supply (D1 & D2), again watching their polarity. Follow these with the two regulators, making sure that you fit each one in the correct position. REG2 is the 7905 and goes on the lefthand side; REG1 is the 7805 and mounts to the right of REG2. Note that both regulators are mounted horizontally on the top of the board, with all three leads bent downwards siliconchip.com.au This view shows the fully assembled PC board. Be sure to use the “correctcolour” RCA socket (or a near equivalent) at each location, so that you can easily identify their functions. Fig.4: the four MAX4451 dual op amps are soldered to the underside of the PC board as shown here. Make sure you install them the correct way around. May 2004 29 5mm from the body so that they pass down through the board holes. Their device tabs are then fastened against the board’s top copper using 6mm x M3 machine screws and nuts. Once the regulators have been fitted, the next step is to install IC5, the LM1881 sync separator chip. This comes in an 8-pin DIL package and mounts on the top of the board in the usual way. Take care with its orientation, though, and note that its earth pin (pin 4) is soldered to the copper on the top of the board as well as underneath. Fitting the surface-mount ICs Use a fine-tipped soldering iron when installing the four MAX4451 dual op amps on the underside of the board. Once they’re in, check your work carefully using a magnifying glass, to ensure there are no solder bridges. You should now be ready to fit the four surface-mount ICs (IC1-IC4), which are the only parts mounted under the board. These are in an 8-lead SOIC package, with 1.25mm lead spacing – so they’re not too small for manual handling and soldering, provided you’re careful and use a soldering iron with a fine-tipped bit. To fit these ICs, invert the board and find the four mounting locations using the underside diagram as a guide – see Fig.4. You’ll find two sets of four small The PC board is secured inside the case using eight 6mm-long self-tapping screws – four along the front edge and four along the rear. 30 Silicon Chip siliconchip.com.au rectangular pads in each position. That done, remove the four devices from their packaging and examine each one with a magnifying glass so that you can identify the small chamfer along one side – this is used to identify pins 1-4 of the device. All four devices are mounted on the board with this chamfered side towards the front – ie, downwards in Fig.4. Each device is installed by first placing it on its set of pads (with the correct orientation) and holding it there using a vacuum pick-up tool or toothpick while you press down gently on one of its eight leads with the tip of your soldering iron. This will usually make a weak solder joint between the lead and the tinning on the board copper – enough to hold the device in place while you solder the rest of its leads to their pads. That done, you can then go back and solder the first lead properly, to complete the job. Completing the PC board The final component to fit is the power LED (LED1). This fits from the top of the board, with its longer anode lead towards the right (ie, towards CON1). Solder the leads in place with the body of the LED about 17mm above the top of the board (a strip of cardboard makes a handy spacer). Bend both leads down together at right angles after soldering, at a point 9mm above the board (ie, 8mm from the LED body). The LED will then be pointing forward horizontally, ready to protrude through the matching hole in the front panel when it is fitted. Fig.5: this is the full-size etching pattern for the top side of the PC board. Drilling the panels At this stage, your converter board assembly should be complete, so place it aside while you prepare the front and rear panels of the case. These each involve drilling and reaming a small number of holes for the various connectors and the LED, using a photocopy of the panel artwork as a drilling guide. Additional photocopies of the artworks can then be cut out and attached to the outside of each panel, to make them look professional, as on the prototype. The way to do this is to first make a copy of the artwork on adhesivebacked “A4 label sheet” paper. The labels are then trimmed, peeled off the backing and attached to the panels. A siliconchip.com.au Fig.6: the full-size etching pattern for the bottom of the PC board. Check both sides of the PC board for etching defects before installing any parts. length of clear packaging tape (ie, wide adhesive tape) is then applied over each panel, to protect it from dirt and finger grease. Finally, the excess tape can be trimmed off around the panels and the holes cut out using a sharp hobby knife. May 2004 31 Fig.7: these full-size artworks can be used as drilling templates for the front and rear panels. Of course, if you buy a complete kit, you probably won’t have to do any of this. Instead, the panels will most likely be supplied pre-punched and with screened lettering for a really professional finish. Now for the final assembly. This is done by first fitting the panels over the connectors on each side of the board (and over the LED in the case of the front panel) and then lowering this assembly into the bottom half of the case – ie, by sliding each panel into its mating slot. It’s then simply a matter of fitting eight small 6mm long selftapping screws (four along the front edge and four along the rear) to hold the PC board in place. Finally, the top half of the case can be fitted and secured from the bottom using the two long countersink-head self-tappers provided. Your Component Video To RGB Converter should now be complete and ready for use. There are no adjustments to make – all you have to do is connect a suitable 9V AC plugpack and it should spring to life. Troubleshooting If it doesn’t work, the first step is to go back over your work and check that all components are correctly positioned and orientated. Check also for missed solder joints, especially where leads have to be soldered on both sides of the PC board. Next, check the power supply rails. There should be +5V at the output of REG1 and -5V at the output of REG2. If you don’t get this, check the two regulators and diodes D1 and D2. You should also be able to measure +5V (with respect to ground) on pin 8 of all ICs and -5V on pin 4 of IC1-IC4. Finally, if LED1 fails to light and the +5V rail is correct, check that the LED has been installed correctly. Check also that its 470Ω current limiting SC resistor is correct. Car Projects, Volume 2 THE PROJECTS: High-Energy Universal Ignition System; High-Energy Multispark CDI System; Programmable Ignition Timing Module; Digital Speed Alarm & Speedometer; Digital Tachometer With LED Display; Digital Voltmeter (12V or 24V); Blocked Filter Alarm; Simple Mixture Display For Fuel-Injected Cars; Motorbike Alarm; Headlight Reminder; Engine Immobiliser Mk.2; Engine Rev Limiter; 4-Channel UHF Remote Control; LED Lighting For Cars; The Booze Buster Breath Tester; Little Dynamite Subwoofer; Neon Tube Modulator. Available from SILICON CHIP Mail order prices: Aust: $14.95 (incl. GST & P&P) NZ/Asia Pacific: $18.00 via airmail Rest of World: $21.50 via airmail Or 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. 32 Silicon Chip siliconchip.com.au 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. Exit sign with battery protection This circuit substitutes two white Luxeon 1W Star LEDs for the inverter and fluorescent tube in a standard battery-backed illuminated exit sign, as used in commercial premises. While the Luxeons have less light output than a standard small fluorescent tube, their directional light is quite adequate for the purpose and they do result in less current drain from the battery. However, the use of a 6V SLA battery for this application means that it can be completely discharged if the 240VAC mains supply is absent for a long period, as can happen when the power to vacant premises is switched off. Such a complete discharge will effectively destroy the battery and must be avoided. This circuit achieves this by switching off Q1 & Q2 when the battery voltage falls below 5.5V, as set by trimpot VR1. For voltages below 5V, the current drain falls to below 200µA. Brad Sheargold, Collaroy, NSW. ($30) the ringer equivalent number (REN) of three allowed on a line. The normal solution to this is to install a splitter and an amplifier at a cost of $170 -$200. This method involves splitting the line as it comes in, having a dedicated socket for the modem and then running all the phones via the one filter. The filters have RJ 12 sockets at each side so the setup can be run with suitable cables and modular wall sockets. Julian James, Coledale, NSW. ($25). One ADSL filter serves several phones In a typical broadband ADSL internet installation, an ADSL filter is required for each telephone or fax machine. This can be an expensive proposition for a home with four or more phones. This method avoids the need for separate filters by having one filter installed in the fixed phone wiring. A typical installation requires a separate filter for each phone and three filters is the recommended maximum, set by Telstra’s limit of CONTRIBUTE AND WIN! As you can see, we pay good money for each of the “Circuit Notebook” contributions published in SILICON CHIP. But there’s an even better reason to siliconchip.com.au send in your circuit idea: each month, the best contribution published will win a superb Peak Atlas LCR Meter valued at $195.00. So don’t keep that brilliant circuit secret any more: sketch it out, write a brief description and send it to SILICON CHIP and you could be a winner! May 2004 33 Circuit Notebook – continued PICAXE home security project This home security project is based on a PICAXE-08 which monitors two infrared light beams, at the top and bottom of a flight of stairs. At the bottom of the stairs, an IR transmitter diode is mounted in the stair column and an IR receiver (sensor A) is installed in its opposite number. Therefore the 38kHz modulated IR beam is broken when a person enters the flight of stairs. A similar arrangement is installed at the top of the stairs (sensor B). An LDR (light dependent resistor) determines whether it’s day or night (ADC numbers) and the program then changes the action of both IR sensors. When a person comes up the stairs during the day, sensor A triggers two wireless remote door bells, one in the house and one in the back shed via a relay, while sensor B is inactive. A person going down the stairs in daylight triggers sensor B to put a 20-second hold on sensor A so that the bells don’t ring. At night, a person going up the stairs triggers sensor A to cause the bells to sound as well as switching on two floodlights to illuminate the front of the house for three minutes. When the B sensor beam is broken by a person going down the stairs at night, the floodlights come on again for three minutes and the doorbell is again inhibited for 20 seconds. There are two other optional input devices: a pushbutton switch inside the house and an LDR circuit that detects car headlights coming up the driveway. The pushbutton will not ring the bell unless the headlight monitor is triggered. Both turn on the floodlights. The circuit works as follows: IC1 is a 555 timer configured as an astable oscillator operating at around 38kHz to drive both IR diodes via 150Ω resistors. When either sensor A's or B’s beam is broken, its respective IR receiver (IRRX1,2) goes high. The respective PICAXE input pin 3 or 4 is also pulled high via diodes D1 or D2. 34 Silicon Chip PROGRAM LISTING main: Readadc 1,b0 if b0 >75 then daylight if b0 <=75 then night daylight: low 2 low 0 if pin3 = 1 then bell if pin4 = 1 then break goto main night: low2 low 0 if pin3 = 1 then both if pin4 = 1 then light goto main both: high 2 high 0 pause 1000 low 0 wait 60 wait 60 wait 60 low 2 goto main 'output 2 is light 'output 0 is bell 'pin3 is A bottom/car headlight sensor 'pin4 is B top/push button sensor 'bell & light 'turn on light & ring doorbell at night '1 sec pause to allow relay on 'keep light on for 3min break: wait 20 goto main 'pauses doorbell in day-lets you walk 'downstairs without triggering doorbell bell: high 0 pause 1000 low 0 goto main 'ring doorbell in day light: high 2 wait 60 wait 60 wait 60 low 2 goto main ‘relay on 1 second 'light on at night, pause doorbell 'to walk down without triggering doorbell These input pins can also be pulled high by pushbutton switch S1 or the headlight sensor, via their respective diodes (D3 or D4) and 4.7kΩ resistors. In fact, D1 & D3 and D2 & D4 and their respective 4.7kΩ resistors comprise OR gates to control the PICAXE inputs. The program determines the continued next page siliconchip.com.au Paul W is this m alsh o winner nth’s o Peak At f the las LCR Meter output state of PICAXE outputs 2 and 0. When driven high, output 2 switches the solid-state relay on via transistor Q1. When output 0 goes high, it switches RELAY1 via transistor Q2 to drive the door bells. The LDR type and series resistor used in the headlight sensor are a matter of choice, as outlined in the PICAXE article in the March 2003 issue of SILICON CHIP. It depends on where the control box is installed, as does the ADC numbers for the determination of day and night. Another important point to remember is if you are programming your PICAXE on a separate board to your project, you may need to tie the serial pin input to ground via a 27kΩ resistor (or thereabouts) on the project board. Paul Walsh, Montmorency, Vic. siliconchip.com.au May 2004 35 Circuit Notebook – continued PICAXE-based car speed alarm This circuit monitors the speed of a vehicle using a Hall Effect sensor and magnets attached to a driveshaft or half shaft, (as described in the Digital Speed Alarm for Cars, November & December 1999). When the magnets go past the Hall sensor, an input signal is fed to IC1 which is a TL071 op amp connected as a comparator. Trimpot VR1 sets the threshold and the output signal is a square wave fed to one half of a 4013 D-type flipflop, IC2. The output of IC2 equates to half a revolution of the wheel, assuming the Hall Sensor is monitoring a vehicle’s half shaft. The PICAXE-08 (IC3) measures the pulse width in milliseconds. It does this four times which equates to four revolutions of the wheel. IC3 stores that information in a memory location. This stored value has a direct relation to the speed of the car. After that, it just keeps comparing the next four readings with the first value stored. If the value is higher, the car is going slower. If lower, the car is going faster. Therefore, it turns on the green or red LED. It also calculates the 5% over-speed value which turns on the piezo buzzer. VR2, the LDR and transistor Q1 control the brightness of the LEDs, to suit the ambient light. To set the speed, turn the unit on (via S1) when the vehicle is doing the desired speed. For a different speed, switch the unit off and then back on again when the desired speed is reached. Power for the circuit comes from the vehicle’s battery via the ignition switch. Diode D1 provides reverse polarity protection, while REG1 provides a stable 5V supply for the ICs. Henri W. Klok, Algester, Qld. ($50) this is enough to attract attention, without the likelihood of waking the whole household. In effect, this circuit simply powers the smoke alarm at 6.8V, as derived from a zener diode (ZD1), so that it sounds its low battery warning. Apart from the zener diode, the smoke alarm draws only a few microamps, with a brief current spike during the “chirp”. Smoke alarms are now very cheap to buy so this is a good alternative to a piezo siren. More information on a common Smoke Alarm chip made by Motorola can be obtained at: http://e-www.motorola.com/files/ sensors/doc/data_sheet/MC144671.pdf Michael Jeffery, Eurobin, Vic. ($25) Low-cost low-intensity alarm Ever needed an alarm to monitor something but you didn’t want to annoy the neighbours or scare the hell out of the family in the middle of the night? Using a feature found in most smoke alarms these days, this little circuit may do the trick for you. When the 9V battery level drops to about 7.4V in most smoke alarms, they emit a brief chirp at around 40 second intervals. In most cases, 36 Silicon Chip siliconchip.com.au PROGRAM LISTING 'w2 'w3 'w4 'get speed reading 'store speed setting 'compare speed value 'start program for b0 = 1 to 4 high 2 pause 100 low 2 pause 100 next 'time to settle 'after switch on 'green led flashing 'get speed setting again: w3 = 0 for b0 = 1 to 4 pulsin 3,1,w2 if w2 >15800 then again w3 = w3 + w2 'take four readings 'prevent over run in w3 'store speed setting next 'start to compare speed chkspd: w4 = 0 for b0 = 1 to 4 pulsin 3,1,w2 if w2 = 0 or w2 > 15800 then error w4 = w4 +w2 next if w4 > w3 then green if w4 < w3 then red red: w5 = w3/20 w5 = w3 – w5 if w4 < w5 then alarm high 4 go to chkspd error: for b0 = 1 to 4 alarm: high 1 high4 low 2 pause 100 low 1 w5 = 0 goto chkspd green: high 2 low 4 w5 = 0 goto chkspd siliconchip.com.au 'again four readings 'speed below range 'actual speed reading 'below speed 'overspeed Silicon Chip Binders REAL VALUE AT $12.95 PLUS P & P '5% of speed limit 'just over speed '5% more over 'speed limit 'check again 'turn on green 'turn off red 'check again pause 500 HIGH 2 Pause 500 Low 2 next w2 = 0 goto chkspd H SILICON CHIP logo printed in gold-coloured lettering on spine & cover H Buy five and get them postage free! Price: $A12.95 plus $A5.50 p&p. Available only in Australia. 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. May 2004 37 Using a Rabbit isn’t rocket science… or is it? FLY FLY Run, Rabbit, Run Remember the RABBIT RCM2100 microprocessor module we introduced to SILICON CHIP readers back in October 2001? Seems lately its brother, the RCM2300, has been soaring to new heights . . . T he Amateur Spaceflight Association (ASA) of Houston, Texas has a mission: “Promote space-related activities in such a manner that safely challenges the technical limits of amateur space flight.” Breaking the world record for amateur rocket altitude would help accomplish this goal but the ASA needs more than a bottle of liquid oxygen, a box of matches and a really long ruler. Given a payload of opportunity, Nicolaus Radford, Chief Avionics Engineer for ASA, went ballistic with the Rabbit RCM2300 Microprocessor Core Module. “I got into Rabbit about 3½ years ago, basically just looking for an 38 Silicon Chip embedded processor that would fit the form factor and capability I was after. I came across the Rabbit Semiconductor web site, bought one and haven’t looked back since,” he said. The ASA’s most recent rocket launch was about 5.6m in length and 230mm in diameter. It pulled about 8.5G on takeoff, broke the sound barrier and flew up to about 3500m. The rocket had video, telemetry, GPS and full dynamical analysis of the rocket, all in real time. To measure all vehicle parameters, including acceleration, velocity, pressure and position, they built a custom data acquisition board that had all the components on it. It used the Rabbit and an I2C bus to read and store data in the Rabbit’s flash memory. At the same time, the Rabbit was also serially interfacing to a terminal node controller and a GPS unit on two serial ports. The Rabbit ran on the I2C bus and read all the different sensors around the rocket, then formatted the data and sent it to the terminal node controller. This in turn formatted the data for packet radio and transmitted it on an amateur radio frequency. GPS readings were also being sent via a telemetry band to the ground. According to Radford, it was very simple to string up multiple I2C controllers and talk to them to get all the data back. “It was great because on a long rocket you have sensors in the nose cone and the body and it was nice to interface with these sensors with two wires instead of a string of wires. We used two of the four serial ports on the Rabbit to interface to a terminal node controller, which interfaced to an amateur radio. We also interfaced to a GPS receiver.” “When you look at how small the RCM2300 is compared to what it does, I don’t think there is anything siliconchip.com.au Getting an 18.5ft rocket ready for launch is not quite as simple as placing it in a large bottle and lighting a long wick! Some idea of the size of the craft can be gleaned from these two photos, courtesy of ASA. on the market that can beat it. You’ve got 40 I/O pins, four serial ports, flash memory to store data – you don’t need any external interface to it to run our system except the core module. The size and space saving is just tremendous for the capability. And it has got relatively low power consumption –110mA at 5V is pretty small!” Critical components of Dynamic C helped Radford get to the launch pad. “We probably could not have done the project in the timeframe and ease that we did if we didn’t have the costate construct. It was just phenomenally easy to use. It basically simulates a multi-threaded environment with hardly any overhead whatsoever. The way Dynamic C time-slices and the way the event control is set up is just amazing. If you were to try to write out and code out to simulate a multi-thread yourself, you would be bogged down in months of coding. I don’t think as a programmer I could make a better utilisation of processing time than what the Rabbit did using the costatement. And I have yet to see this anywhere else.” The development time to completely get the system up and running was eight months. “Had we not had the development kit and protoboard to easily interface the programming pins of the Rabbit, had we used some Front view of the payload/electronics section of the rocket (red section at top). siliconchip.com.au other processor where we would continuously have to fabricate our own ways to interface to the processor, it wouldn’t have been nearly as fast. It was really nice that the pins were broken out to individual headers on the protoboard – that made development tremendously easy. The readyto-go protoboard surface mount pads helped significantly as well. My best guess is that our development time would have been twice as long if we hadn’t gotten these benefits in the development kit.” During flight, the rocket performed perfectly. It wasn’t until on the way down that ASA had a scare in the form of a failed main parachute. Upon landing, their data told revealed a 61G impact. Even though the backup parachute successfully protected the entire rocket, it was pretty impressive that the Rabbit withstood the shock. Commercial spin-off There has already been a product spin-off from the project: a data acquisition system aimed toward the high-powered rocketry community. The rocketry community is all about size – how small can you get it? The Rabbit will enable a product which can be taken to market that will be superior to anything currently available for a data acquisition system in high-powered rocketry applications. The first thing that struck the ASA designers was how small the RCM2300 was for what it did. That was extremely important because there was not a lot of space to work with. The benefit over say, a PIC processor, is that the Rabbit not only has three times the processing power but also has all the extra overhead and the flash memory interfaces that need to be added onto a PIC. So what is in store for ASA? The launch described here is in preparation for a space shot to be attempted early next year, using a 12m liquid motor vehicle. It will enter space, reach 120km and return. There will be many Rabbits on that flight. With the design calling for throttle control ability, one Rabbit will be used for liquid motor throttling and data acquisition of the liquid motor; another to analyse power usage and to turn things on and off as they are needed to conserve power. For more information on ASA, visit: www.asa-houston.org Dominion Electronics are the Australian distributor for all Rabbit products. Ph 9906 6988. Watching the data coming back to earth, courtesy of the Rabbit and an amateur radio link. Photos: ASA. May 2004 39 SERVICEMAN'S LOG Nothing succeeds like a good whinge Some people really are born whingers. Couple that with someone who also refuses to accept responsibility for his own negligence and you’ve got the classic “difficult” customer – especially when they try to shift the blame elsewhere. We had a guy bring in a 3-year old Philips TV, claiming that the set had suddenly stopped working and that it was under warranty. Fair enough. I was the muggins who was allocated to fix the set. When I switched it on, it was dead. I removed the back and found that the cause was pretty obvious – there was a 130mm crack in the main PC board around the flyback transformer. This crack was open by over 5mm in some sections and the set had obviously been dropped from quite a height. There were also several cracks and scratches in the case, again consistent with the set being dropped. In view of this, it was quite likely that the 51cm flat picture tube had also been damaged internally – especially the shadow mask which is easily dislodged and gives major uncorrectable colour purity errors. We had a little meeting and it was decided to confront the client. After all, the purpose of a warranty is to guarantee that the product is fit for its purpose and free of any manufacturer’s defects. It is not there for people to claim free repairs if they damage the product through their own negligence! After all, a TV set is not a football. Well, despite the overwhelming evidence that this set had been dropped from a considerable height, possibly from a wall stand, the client insisted that the set had failed all by itself and that we were negligent and had probably dropped it afterwards! We couldn’t get through to him that the only course of events consistent with the facts was that the set was working 40 Silicon Chip and that it had stopped working only after it was dropped. I even repaired the crack to show him that that was the only electrical fault with the set, apart from the damaged picture tube which indeed had horrendous purity errors. A Philips insurance company assessor was called in and, even more amazingly, decided to give the client the benefit of the doubt. And as the 3-year old set was beyond economic repair, it was written off and the client given a new one! I guess no matter how illogical you are, if you are good enough at whinging, you will win out in the end. Frankly, I have little time for such people and he really should have been told to go take a running jump. Now what’s the address of that whinging school? Third cab off the rank I had never even heard of AEA Skysonic TV sets, let alone seen one, until the day George Western brought his CTV-8298S 68cm unit in. I was Items Covered This Month • • AEA Skysonic CTV-8298S Philips 29PT5783/79R TV set (A8.0A chassis) • Sony KV-EX29M39 TV set (SCC-V41B-A, AG-3E chassis) • Panasonic TX-68X02A TV set (MX10A chassis) • Grundig M70-575/90 TV set (CUC5836 chassis) about third cab off the rank in the list of people he had tried to get to fix his TV and I took it on more out of interest than anything else – especially as the fault was only in the east-west correction circuits. As it turned out, none of the three preset controls – VR2000 Pincushion, VR2001 Width and VR2002 Trapezium – worked on the E-W Module. I could see from the fresh soldering that a lot of work had already been done around the flyback transformer, horizontal output transistor and east-west modulator diodes but it all had to be checked again. This I did by removing each component to be tested from the circuit but everything checked OK. I also removed the east-west module and checked the output transistor but this was also OK. As I looked at the chassis, it slowly dawned on me that I had seen this Chinese-built set before. But where? I tried looking at Akai and Teac service manuals but there was no similarity at all. I was about to give up on this approach when I suddenly remembered Masuda. I went through the file on that brand to find a pretty good match with the Masuda S25TXS. Now that I had a circuit diagram the job had suddenly become a lot easier. I checked all the transistors on the east-west module and then began checking and replacing the electrolytic capacitors. I replaced C330 and C328 on spec but it was C329, a 4.7µF 50V bipolar capacitor, that made all the difference. Despite measuring OK on the capacitance meter, replacing it fixed all the symptoms. Finally, I realigned the three controls using a crosshatch generator and Mr Western was a happy chappie! The green Philips I had another Philips TV (29PT5783/79R using an A8.0A chassis) come in with no picture. The sound was fine but there was only a very dull green raster on the screen. It took siliconchip.com.au some considerable time to examine the EHT “Info” line (as Philips call it) and the ABL (automatic beam limiter) and video circuits to finally establish that the fault was in the picture tube (A68ESF003X11) itself. Next, I connected my ancient SWE-CHECK analyser onto the tube with an upgraded adaptor. The neon indicators suggested that there was an unspecified short in the blue gun. I say “unspecified”, as the display was not shown in the user’s guide for the analyser. I then tried to measure the emission but there was none at all on the blue gun While I was doing this, the phone rang and I had to answer it, inadvertently leaving the analyser switched on and connected. When I got back, I was amazed to see that the short had cleared and that the emission was fully restored. Anyway, I reconnected the tube to the set and switched it on. The tube started up as before – a dull green, then a brighter blue and finally a full colour picture. Unfortunately, the greyscale was not only poor but kept changing all the time by itself. I kept it on test and every so often the short would reoccur but treating it again with the SWE-CHECK always fixed it. However, the repair just wasn’t siliconchip.com.au good enough to guarantee, no matter how hard I tried. Eventually, I recognised that it had to be abandoned and I had to inform the client that the set was beyond economic repair as it needed a new picture tube. He was fairly philosophical about this and promptly went out and bought a new set. The dead Sony A 2000 Sony KV-EX29M39 (SCCV41B-A, AG-3E chassis) came into the workshop marked “dead”. However, it wasn’t totally dead – the standby LED was flashing twice, indicating overcurrent protection. ELAN Audio The Leading Australian Manufacturer of Professional Broadcast Audio Equipment A quick check revealed that the line output transistor and flyback transformer were short circuit. It all seemed straightforward and so the client was quoted just to replace these two items, which he grudgingly accepted. But, quelle horreur! After replacing them, the set was still dead and the LED was now flashing six times, denoting horizontal deflection failure. Testing the deflection board more thoroughly with the ohmmeter, I found that the 9V rail impedance was down to only 87Ω. This rail was only released when board D1 was removed. Examining this board more closely, I eventually found that op amp IC6107 2 Steel Court South Guildford Western Australia 6055 Phone 08 9277 3500 Fax 08 9478 2266 email poulkirk<at>elan.com.au www.elan.com.au RMA-02 Studio Quality High Power Stereo Monitor Amplifier Designed for Professional Audio Monitoring during Recording and Mastering Sessions The Perfect Power Amplifier for the 'Ultimate' Home Stereo System For Details and Price of the RMA-02 and other Products, Please contact Elan Audio May 2004 41 Serviceman’s Log – continued (CA0005A, P. BAL CONT) was the culprit. Replacing it was easy and fixed the set. The difficult part was re-quoting the client. An unusual Panasonic I had an unusual problem with a brand new Panasonic TX-68X02A employing an MX10A chassis. This uses a very small chassis which is tucked under the tube on a plastic frame. The problem seemed straightforward – there was no sound on the right channel on the AV1 and AV3 inputs. By contrast, AV2 and TV were both OK. Most sets nowadays have a neat little circuit that automatically ensures that the sound also comes out of the right channel when you connect a mono input into the left channel. This MX10A uses microprocessor IC2101 and IC3007 to control all the AV switching and this circuit was working correctly. The only problem was when using the two rear AV inputs and the monitor output mirrored the sets symptoms. I started by going to the “Self Check Mode” via the market mode – ie, by reducing the volume level to zero, pressing the OFF TIMER to 30 minutes and then pressing the RECALL 42 Silicon Chip on the remote and VOLUME “–“ on the TV simultaneously. Everything looked OK, including the options. I then swapped the output AV-Module H-board with one from another set but it made no difference. By now, it looked to me as though it was the 80-pin surface mounted microprocessor (IC2101, MSP3410GQABB) on the underside of the main board. This was confirmed as being a likely suspect when I spoke to the Panasonic Technical Officer, so I ordered one in and removed the main board from its plastic frame to gain access to the copper side. Actually, replacing the IC was an interesting exercise, involving a new Hakko 852 ESD SAFE SMP Rework Station air-gun. Hot air was applied for a few minutes via a specially fitting IC tip and, after a gentle rotating action, the IC eventually fell off when the glue gave way (you can get an extra heater that melts the glue faster). The beauty of this was that all the heat was applied directly to the IC pins and did not affect surrounding components. The pads were then cleaned with Soderwick and alcohol. Next a flux pen was applied over the nice clean solder pads before fitting the new IC. The new IC was then anchored and adjusted into an exact position by soldering just two pads at opposite ends. That done, the solder was melted and allowed to flow all over the pads simultaneously until each leg was soldered. Finally, any shorts left were sucked up with Soderwick and the flux removed using alcohol. The completed result looked just like the original! After I had reassembled the set and switched on, I was horrified (again!) to find I now had no sound at all from any source. It took a long time to realise that the fault had to lie with the new IC and so it had to be removed and resoldered. Of course, you wouldn’t have been able to do that with an ordinary desoldering station! As it turned out, there was a short due to a solder “dag” underneath the IC. This was located well behind the legs and so couldn’t be seen from the top or side. Oh well, practice makes perfect! Unfortunately, all this effort with the new microprocessor left me with same symptoms I had started with! But at least I now knew that it wasn’t causing the problem. The problem with using oscilloscopes for checking sound is that it is easy to mistake noise and distortion for sound. The best way is to use a small amplifier probe and your own ears will tell you what you should be getting. I have quite a few of these probes but the downside of this equipment is that it is so easy to blow them up by con- siliconchip.com.au necting them to the wrong rails. I am constantly either repairing or making new ones. Anyway, I was now doing what I should have done right at the beginning and that was trace the input from the right channel, no matter how difficult access was to the miniature copper pattern underneath the board. With great difficulty, I eventually found the sound was getting to A11 (pin 5) of the microprocessor but was not arriving at pin 57 of IC2101. I then traced the sound to C2005, a surface mounted capacitor, but no further. A careful examination of the capacitor showed the cause of the whole problem. One end of the capacitor was dry jointed and a quick resoldering job fixed it. Grunting Grundig Mr Bayer brought his Grundig TV set in, complaining that it was “grunting”. Being a small man, I wasn’t quite sure at first whether it was him or the set which he had just carried from his car that was suffering these symptoms. Anyway, I was grateful that he had done so, as I didn’t think it likely it could be fixed in his home. The Grundig M70-575/90 uses a CUC5836 chassis and this was not so much grunting as pulsating, with no sound or picture. I removed the back and went straight to the horizontal deflection stages where I suspected the problem to lie. First, I unsoldered the separate tripler and tried again. I was not surprised when I next found that the horizontal output transistor (T541, BU508AG) was short circuit. I had never heard of a BU508AG and none of the catalogs had any data on the ‘G’ version. Fortunately, I did have a service manual which showed the 2SD1432 and 2SD1884 types as equivalents, neither of which I had in stock. However, I had an uprated 2SD1887 which I slipped in. Before switching the set back on, I removed the flyback transformer (TR529) and checked it with the shorted turns tester. I also checked the tuning capacitors and diodes and all around the horizontal deflection stage, just in case these destroyed the new transistor. Finding nothing wrong, I switched it on again – it was still pulsating but it didn’t immediately destroy the new transistor. I next concentrated on the horizonsiliconchip.com.au tal drive circuit and replaced IC500 TDA8140, as well as electrolytic capacitors C507 (1000µF 25V) and C541 (220µF 40V). This time, the set rose from the dead with both sound and picture. The only trouble was that the picture was terrible. First, there was pincushion distortion and severe “cogging” (as I call it). This is a line tearing effect, where the edges of the picture are serrated like a gear cog, especially on bright scenes. Anyway, I decided to deal with the east-west pincushion problem first. I removed and examined the module where two ICs handle all the picture correction and it didn’t take too long to find that D7012, a 36V zener diode, was almost completely short circuit. Replacing this diode didn’t make any difference until I also replaced R546 (4.7Ω) which feeds the horizontal deflection yoke. All I had left to deal with now was the “cogging”. This “smelled” of dried out electrolytics causing ripple on the supply rails. However, after spending a lot of time investigating this – both by using a CRO and by hanging additional electrolytics on the noisier rails – I decided that this was the wrong track. Most rails are noisy anyway and it is difficult to know what is significant and what isn’t, especially as there are no details in the service manual. Back to the start In the end, I went back to where I started and checked the waveforms around IC500, the horizontal driver. Everything was sweet except for the output on pin 1 and the feedback on pin 3, where the waveforms were unstable. There wasn’t much in this circuit which I hadn’t already replaced or tested, so I had to repeat my previous work, but this time more accurately measure the components out of circuit. I had already checked R544 (0.12Ω) in circuit with the DVM and it seemed pretty well right. The circuit I had for a CUC5880 states that it is 0.1Ω but the one in this set was 0.12Ω. I checked it using the ESR low ohms meter and found that it actually measured 0.09Ω. This doesn’t seem significant but it is actually about a 25% error. Anyway, replacing this low-value resistor finally fixed the set. Mr Bayer grunted quite a bit when I gave him SC the bill. May 2004 43 SILICON SILIC CHIP siliconchip.com.au YOUR DETAILS NEED PCBs? 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Books: Aust. $10 per order; NZ: $AU12 per book; Elsewhere $AU18 per book OR PAYPAL (24/7) OR Use PayPal to pay silicon<at>siliconchip.com.au PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with your credit card details *ALL ITEMS SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES IN AUSTRALIAN DOLLARS AND INCLUDE GST WHERE APPLICABLE. OR MAIL This form to PO Box 139, Collaroy NSW 2097 siliconchip.com.au 5/04 AUTUMN BARGAINS Component Video to RGB Converter Kit The ultimate toy for the bathtub, pool, or fish-tank. They have full manoeuvrability with forward, back, left, right, and also a power dive button to dive quickly to the bottom. They feature and LED headlight, so they can even drive in the dark! Use two different frequency models to have underwater battles and races! Two frequencies available: 40MHz Blue Cat. GT-3045 27MHz Yellow Cat. GT-3044 NEW MODEL Both Types $ .95 Each Ref: Silicon Chip May 2004. Top quality home cinema is increasingly common in many houses. The super high quality of Component Video is the best on offer - but what if your projector or plasma TV etc only has RGB inputs? This unit converts the Component signal to RGB format with minimal signal degradation. Kit supplied with PCB, case, silk-screened and punched panels, colour coded RCA sockets, 9VAC plugpack, all electronic components. 29 Large measures 235(L) x 40(dia)mm Cat. ST-3342 OUR MASSIVE 424 PAGE CATALOGUE IS NOW AVAILABLE! 1168 South Rd. Clovelly Park. OPENS SA. 5042. Ph: (08) 8276 6901 MAY Our Gore Hill Store is moving to 96 Pacific Highway, St. Leonards. NSW. 2065 You can still call us on (02) 9439 4799 Multi Purpose Ear Thermometer A great product to have on hand for the unexpected illnesses that may arise. It uses infra red technology to provide quick and accurate temperature readings on the LCD in just 1 second. It is a versatile instrument which not only can be used for the body but also other circumstances such as testing the temperature of a baby’s bottle, bath water or measuring room temperature. •Temperature range: 0 -100°C (32 - 212°F). •20 disposable probe covers (included). •158(L) x 40(W) x 54(D)mm. You can find it in store for $3.95, or get it FREE when you purchase the May issue of Silicon Chip magazine NEW LARGER MODEL NEW STORE IN ADELAIDE We’re Moving GRAB YOUR COPY NOW High Definition Digital Terrestrial TV Card for PC’s This state-of-the-art VisionDTV Terrestrial Card allows you to watch both standard and high definition digital TV through your PC. The card fits into a spare PCI slot and gives you some amazing features. See our website for features & specs. Widescreen (16:9) and standard (4:3) aspect ratios supported. Was $299 Cat. XC-4819 199 $ 49 .95 18 0 0 0 2 2 8 8 8 Freecall For Orders SAVE $100 Flickering Electronic Candle SAFE, INTIMATE ILLUMINATION WITH NO FLAMES Enjoy the charm and intimate glows of a candle without the messy wax residue and danger of fire. The secret is an electronic candle module (shown) with a special glass diffuser screen. The module has rechargeable batteries which will last for ages and never need replacing. A “slave” candle will work from the same charger via a discrete cable. Works up to 10 hours. •Both the ST-3922 and ST-3920 include a shade each. Cat. $ .95 Candle with Charger ST-3922 29 Cat. $ QM-7227 99.95 Cat. $ KC-5388 OUR NEW 2004 CATALOGUE IS HERE Faraday Hand Powered LED Induction Torches No batteries required! To use one of these torches, you simply shake it up and down. The internal mechanism charges a small battery which in turn, powers the torch. If the torch starts to dim, just shake it up again to restore full brightness! They are waterproof and lightweight, made from strong ABS plastic. You won’t be caught with a powerless torch again! Two sizes available: Cat. $ .95 Small measures 165(L) x 37(dia)mm ST-3340 14 $ 24.95 MAINS PLUGPACK INCLUDED May 2004 Power Dive Radio Controlled Submarines •Spare Candle Cat ST-3920 $14.95 •Glass Frosted Shade Cat ST-3923 $5.50 •Glass Frosted Shade Metal Trim Cat ST-3924 $5.95 Digital Hand Shower / Tap Thermometer This thermometer is designed to be fitted inline with your hand shower or tap and helps prevent scalding by displaying the actual water temperature coming through the spout. It measures between 0 to 50°C (32 - 122°F) in 0.1° steps. See website for details. Cat. GH-1350 14.95 $ 4 Litre Peltier Effect Cooler / Warmer This 4 litre cooler and warmer has it all it’s compact, portable and environmentally friendly. It features Hot/Cold operation, On/Off switch and a Red/Green LED indicating warming or cooling. Store your drinks (up to 6 x 375ml cans) and sandwiches. It cools 20-25 degrees below ambient and warms to + 65 degrees. It can be powered from 12VDC or 240VAC. •248(D) x 185(W) x 265(H)mm. 29 49 Cat. $ GH-1375 .95 Wireless Stereo Earphones with Auto-Scan FM Radio This radio headset comes with an FM transmitter that can be plugged into any audio source with left and right RCA connections. All you need to do is tune the radio to pick up the transmitted signal. The earpiece has a clip to secure it to your ear, making it a great wireless headphone for around the house and a portable radio in one. 39.95 Cat. $ AA-2100 9.95 79 Digital Map Distance Calculator Take the guesswork out of map measurements by simply rolling the tip of this handy pen style measure along the desired route. Matching the measure to the map is as simple as entering the map scale on the unit's keyboard. Once calibrated, the distance covered by the wheel is displayed on the screen in either miles or kilometres. •125(L) x 30(H) x 20(D)mm. AA Kingcell Alkaline Batteries Bulk 40 Pack Our AA Kingcell batteries sell for 99c ea in a pack of 4. These are just 50c ea. THAT’S ALMOST HALF PRICE! 19.95 Cat. $ SB-2332 29 It produces a maximum 5 watt output. It features a comfortable pistol grip, and a 435mm shoulder strap which makes it portable and comfortable for long periods of use. It is the ideal instrument for sporting events, crowd control and group gatherings. •Instruction manual included. •Requires 8 x AA batteries (not inc) •Weight: 1 kg •195 (W) x 320 (L) mm More than just a USB powered FM Radio. It can be programmed for unattended recording of your favourite programs and uses an ultra stable Phase-locked-loop PLL tuning system to eliminate station drift. Cat. $ .95 See website for details. XC-4880 $ Wake up to the sound of funky beats with this disco alarm clock. It is retro silver and features a dual time and alarm function. There are seven upbeat tunes you can choose from, to personalise your alarm wake up call. When the alarm goes off, the clock flashes red, blue and orange disco lights. In addition, the clock hands glow in the dark, the volume level is adjustable and the stereo speakers will ensure that you do look forward to hearing the alarm go off! •155 x 130 x 125 mm Cat. $ .95 XC-0160 Hand Held 5W Megaphone with Strap Extreme USB Radio with Remote Control FM Automatic Scan Radio This FM automatic scan radio searches for radio stations with the touch of a button. It has a brushed aluminium finish which gives it that stylish look. •44(L) x 44(W) mm •Freq range: 88-108MHz (FM) Cat. AR-1770 Disco Alarm Clock Electronic Airplane Skywriter Just spin the airplane around in a circle and a message will appear in mid-air before your very eyes! The skywriter has 15 preset messages ranging from "I Love You" to "Happy Birthday" to "Let’s Party." It is also accompanied with an appropriate melody to match the message! You can easily program a message of your own using the alphabets or symbols. Great at parties, special events or sporting event. Suitable for ages 5 and up. Cat. $ .95 XC-0196 79.00 Cat. $ AM-4056 Laptech Personal Coach for Lap Swimming The Laptech is a fantastic aid to anyone who swims laps for competition or fitness. This waterproof timer is simple to use, just tap the face at the end of each lap. In addition to the features you would expect, it records the times of your last 50 laps showing total time and best lap time, best ever 3 laps, and much more. Cat. $ XC-0210 59.95 Commercial Grade Doorway Beam This commercial grade doorway beam is perfect for use across gateways or garage doors; basically anywhere you need a longer range than our standard model. Importantly, this unit has been designed to be used in genuine commercial environments such as warehouses and parking lots where a more robust unit is required. The enclosures are IP66 rated for use in damp or dusty environments. •Max range: 30m •Voltage: 10 to 24V DC Cat. $ LA-5196 95 Cat. XC-0375 19 $ .95 Alcohol Breath Tester with Readout Budget Personal Breath Analyser Unlike many other personal alcohol detectors available, this pocket sized unit is both accurate, and easy to use. It will detect blood alcohol levels as low as 0.01%. Cat. $ QM-7292 Gives a simple Go or No Go indication of blood alcohol. An LED illuminates at over 0.05% blood alcohol. See website for details. Was $29.95 SAVE $10 Cat. $ .95 QM-7290 19 59.95 It offers a good indication of blood alcohol levels, but should not be relied upon and you should never drink and drive. It offers a good indication of blood alcohol levels, but should not be relied upon and you should never drink and drive. www.jaycar.com.au Online Internet Ordering Turbo Camping Shower Anti Fog Shaving Mirror with Radio Add a touch of luxury to that outback adventure. Use a bucket of warm water, and your vehicles battery, and enjoy a shower no matter how far from civilisation you are. 2003 Cat. Price $27.50 This splash proof radio is designed to hang on the shower head and isn't bothered by steam or the occasional splash of soapy water. The radio also has a fold-out anti-fog mirror so you can actually shave in the shower (blade only - of course). Actual model is white. SAVE $7.55 19.95 Cat. $ YS-2800 29.95 Cat. $ GH-1059 7" TFT LCD Colour Monitor for Cars Novelty Farting Man Watch high resolution pictures in widescreen format. A truly versatile monitor with low power consumption, wide viewing angle, NTSC and PAL compatibility. Includes IR remote control Cat. $ QM-3752 Endless fun for all jokers old enough to understand. This animated man turns his head, drops his pants and lets off a series of rip-roaring farts when someone passes by. Uses 3 x AA batteries, included. Cat. $ .95 GT-3100 24 399 The Amazing Flygun The Amazing Flygun is a spring powered gun that kills flies and mosquitos! It is fun, safe, and easy t o use. You can become a hunter in your own home! Simply push the swatter onto the gun and you are ready to swat flies. A 1 metre long string is attached so the swatter doesn’t get lost, you can then reload, aim and fire again. Its fun and effective, and really does work! Cat. YS-5545 9.95 $ Safe for Kids 8 Litre Collapsible Bucket This great 8 litre bucket collapses down to pack away, so it’s ideal for camping, hiking or any situation where storage space is an issue. Supplied with a great storage pouch. Measures 255 x 35mm when folded, 255 x 230 when open. Cat. GH-1260 14.95 $ Superbright SMD LEDs for Mobile Phones These surface mount LEDs are used to illuminate the keypad and display of many popular mobile phones. They do require surface mount soldering skills to mount them, but the results are fantastic. Supplied as a pack of 6, but two packs or more may be required. Phone not Cat. $ .95 Blue included ZD-2020 Cat. $ .95 Pink ZD-2022 Cat. White ZD-2024 $ .95 14 24 19 Willy the Flashing Man For the Practical Joker's bar... He looks to see who’s watching, then opens his coat and drops his pants while playing a great mix of tunes. Hilariously funny. 24.95 Cat. $ GT-3102 GREEN MACHINES! - SELF POWERED DEVICES Dynamo and induction powered devices for endless power (with a little help from you). The torches are great for emergency or backup situations because as long as you can pump or wind them, they will never run out of power. See also the Faraday torches on the front page! Dynamo Wind-Up LED Torch It features 3 super bright LEDs, side cushion grips, and switch selection between 1 and 3 LEDs. One minute’s winding will give you about 30mins of light. It is water resistant and made from ABS plastic. Measures: 130(L) x 50(W) x 45(D)mm. 29.95 Cat. $ ST-3337 Hand Powered Dynamo Torch Ever been caught in the dark with a torch but no batteries that work? This torch has a small dynamo inside that powers the globe when you pump the handle. A torch that lasts forever, no batteries required! Measures just 145(L) x 65(W) x 58(D)mm. Cat. ST-3335 14.95 $ 18 0 0 0 2 2 8 8 8 Freecall For Orders Faraday Hand Powered 8 Digit Calculator The battery free calculator is powered by shaking the calculator side to side. If the screen starts to fade, you won’t lose your information - just shake it again for more power. Functions include ON/C, CE , +, -, X, ÷, % M+, M-, and MRC. •135(L) x 85(W) x 20(D)mm. 14.95 Cat. $ QM-7275 4 in 1 Dynamo Powered Universal IR Remote Control This attractive universal remote control is pre-programmed and has a built in dynamo that charges the internal cell which runs the unit. Just a few easy turns per day is all that is needed to keep the remote fully charged.•210(L) x 55(W) x 30(H)mm. 59.95 Cat. $ AR-1718 Remote Controlled Flying Saucer A fantastic toy for kids of all ages. This untethered, radio controller flying saucer soars into the air as you pull the trigger on the pistol-grip remote controller. Flying height can be varied and you can climb and descend at will. Flying time depends on how vigorously you fly the saucer and varies up to several minutes. The launch pad/charger can be powered by the supplied mains adaptor or fitted with optional 'AA' batteries and will re-charge the saucer in less than 10 minutes. The flying saucer is fitted with its own rechargeable battery. Recommended for indoor use only. •Saucer diameter 230mm. DUE LATE MAY 69.95 Cat. $ GT-3004 FANTASTIC NEW ADDITIONS TO OUR RANGE OF BOOKS We have a great new selection of books available. For full details and information, see our new 2004 catalogue or website. Computing Technology for the Older Generation A great range of books to help explain and guide the older generation around modern technology. A range of useful instructional and troubleshooting books for computing. Windows XP for Beginners Computing for the Older Generation Cat. BB-7070 Cat. BB-7060 Internet for the Older Generation Windows XP Explained ESPECIALLY WRITTEN FOR THE OVER Cat. BB-7062 Find Anything on the Internet for the Older Generation Cat. BB-7064 Digital Photography & Computing for the Older Generation Cat. BB-7066 Creative Gardening with a Computer for the Older Generation Cat. BB-7068 Internet Banking and Shopping for the Older Generation Any Book $ Cat. BB-7072 Easy Windows XP Troubleshooting 50’s Cat. BB-7069 (Each) Cat. BB-7074 Easy Internet Troubleshooting Cat. BB-7076 Easy PC Troubleshooting Cat. BB-7078 Easy PC Website Construction Cat. BB-7080 29 .95 Digital Photography with a Computer Cat. BB-7082 Electronics Using Photoshop 7 Great additions to our range of Electronics references. Cat. AVR an Introductory Course $ BT-1372 Cat. BB-7084 89.95 Easy PC Peripheral Troubleshooting Cat. BB-7086 World's Transistors Diodes Thyristors & IC's Comparison Tables Vol.1 A - Z Cat. $ BM-4594 World's Transistors Diodes Thyristors & IC's Comparison Tables Vol.2 1n…60,000…u PC Interfacing Using USB 39.95 Cat. BB-7088 Easy PC Interfacing Cat. BB-7090 39 Cat. $ BM-4595 .95 Any Book (Each) 19.95 $ Robotics These robotics books are so great - they each deserve a special mention. Further information can still be found in our 2004 catalogue, or on the website. Robotics, Mechatronics, and Combat Robots - Everything You Robot Builder’s Sourcebook Artificial Intelligence Need to Build, Compete and Win If you are going to really get This book, written by Robot Wars veteran Chris Hannold goes into considerable detail on the core subjects you need to master to understand this discipline. Covered are subjects like Electronics and Wiring, Remote Control by RF, Servos, Wheels, Batteries, Motors, Weapons systems, 3 actual robot designs with CD-ROM Plans, and much, much more. Once you have read this book, you are ready to rumble! •Softcover 230 x 180mm, over 300 pages. 49.95 Cat. $ BT-1363 USB 2.0 Video Capture Box This great device can be used to preview, record, or playback your movies from VCR, camcorder, or DVD on your PC. Video can be captured using MPEG1 or MPEG2 format which can be edited and burnt. Use the snapshot feature to capture still images for an electronic photo album. Compatible with Windows 98/Me/2000/XP. •Includes capture and editing software. •InterVideo WinProducer 3 to edit & burn as VCD or DVD disc. •Snapshot capability. •High resolution up to DVD quality. •Supports resolution up to 720x480(NTSC) / 720x576(PAL). •Max frames per second: 29.2. 99.00 Cat. $ QV-3090 serious about robot construction, you must have this massive book! It is so good, Jaycar is even listed in it!! It lists suppliers of all the bits-inpieces you are ever likely to need to pursue the construction of your dream machine. It also includes lists of relevant books, societies, help groups, services, you name it. You not only get component sources, you get materials sources, as well as manufacturing facilities. In all, over 2,500 sources for robot parts. OVER 700 PAGES!!! We have never seen a book before that encapsulates a subject from beginner to serious constructor in one volume. This book encompasses all of the basic control systems – along with the philosophy behind them. The format is extremely practical in that the author provides - literally - hundreds of useful circuits, which are invaluable to practical design. Indeed the components specified are mostly available from Jaycar. •Softcover 230 x 150mm 297 pages 110.00 49.95 Cat. $ BT-1370 Cat. $ BT-1365 Video Enhancer and Stabiliser for S-Video 4 Channel BNC to RJ45 Video Balun TX/RX Connect up to 4 CCD cameras to a single CAT 5 cable. It simplifies surveillance cabling and increases transmission distance by converting from coaxial to Cat 5 cable. Cat 5 cable is low cost, easy to install and commonly used in computer, tele-communications and data industries. One of these devices is required on each end. Transmission Distances (approx.) Solid Wire: B/W video signal - 500m By adding a small high frequency boost to the Colour video signal - 300m video signal, this degradation can be reduced and a better copy obtained. The system will also remove Stranded Wire: B/W video signal -360m Colour video signal - 180m some copy protection information including 'Macrovision 4' which can degrade quality. Cat. $ .95 QC-3427 Mains plug pack and RCA cable supplied. Cat. $ .95 AR-1822 Home VCRs are not designed to produce high quality copies of video tapes and you will usually get poor results when making copies of your favourite tapes. 79 129 www.jaycar.com.au Online Internet Ordering JC80 Double 8" Speaker Kit This brand new speaker kit includes 2 fabulous Vifa 8" Woofers and a Vifa D26 tweeter. The woofers include 30oz magnets, long throw butyl rubber surround, mineral filled mica polycone supported on a very rigid die cast magnesium basket. The tweeter is a high power Vifa D26 which provides accurate response and high performance. The crossovers are pre-built. This kit is based on the ever popular JV60 kit, which we sold for a number of years, and outperformed speakers costing twice the price and more. Power handling is 100WRMS, and impedance is 4 ohms. Limited quantities available, so be quick to avoid disappointment. Speaker Kit - Pair 179 30 WRMS 6.5”Home Unit Sub-Woofer 379 OUR MASSIVE 424 PAGE CATALOGUE IS NOW AVAILABLE! Find it in store for $3.95, or get it FREE when you purchase the May issue of Silicon Chip 89 Universal Amplifier Modules Suitable for a number of applications, they feature flexible input voltage, and suit a range of speaker impedances. Great value. See website for details. 3.5 Watt Cat. $ .95 AA-0223 12 Watt Cat. $ .95 AA-0225 17 23 44.95 $ Compact System Supplied with a 9V battery for power. SAVE Was $49.95 $5 Cat. $ .95 AM-4054 44 Deluxe Rechargeable System SAVE Supplied with $10 charger, requires 6 x AA rechargeable batteries. Was $99.00 Cat. $ .00 AM-4052 89 Now you can have a great sounding, powered subwoofer, even if you live in a home unit of flat. It uses a 6.5" sub, powered by a 30WRMS subwoofer amplifier. Excellent sounding bass. Was $169 SAVE Cat. $ $20 AA-0512 149 3 Piece Add On for Surround Speaker Systems 3 Way Weather Resistant Speakers - Pair These great speakers house a 4" polycone mid, 2" mylar mid tweeter and a 3/4" cloth tweeter. The cabinet is made from high impact black plastic, with a metal perforated grill. 90dB sensitivity, 4 ohm impedance, and 25WRMS power handling. Limited quantity available. BARGAIN Cat. $ .95 CS-2432 Size: 203 x 133 x 127mm 18 0 0 0 2 2 8 8 8 139 $ 120WRMS power handling, 15" woofer, 3 x piezo tweeters, and a wide dispersion piezo horn. Was $209 SAVE Cat. $ $30 CS-2515 These are fully built with a light wood grain finish. Grills supplied with speaker cloth mounted. You simply solder the crossover wires and screw the speakers in. Cat. $ CS-2582 Freecall For Orders Great New Low Prices 15” - 120WRMS Power Handling Cabinets - Pair Designed to be worn around the waist. Both systems are surprisingly loud for their size, and are great for small PA applications such as in-store demonstrations, tour guides and lecturers etc. Allows hands free operation. 100WRMS power handling, 12" woofer, 2 x piezo tweeters, and a wide dispersion piezo horn. Was $159 Cat. CS-2512 589 Personal PA Systems 12” - 100WRMS Power Handling SAVE $20 Includes 4 woofers, 2 tweeters, 2 crossovers with polyswitches, rear terminals, ports, innerbond, and self tapping screws for mounting speakers and crossovers. Cat. $ CS-2580 40 Watt Cat. AA-0227 Party Speakers These specialised party speakers don’t claim to be HiFi speakers, but they do provide good performance in difficult locations such as backyards, tents, party rooms, and halls etc. This kit includes a shielded centre speaker, containing a 4" mid woofer and 2" tweeter, and a set of satellite speakers, each with a 4" heavy duty full range driver. They have black ABS cabinets with cloth grills. Sizes: Centre: 286x184x127mm 6-8 ohm impedance, and Satellites: 181x89x127mm 25WRMS power handling. Limited quantity available. BARGAIN Cat. $ .95 CS-2465 99 Analogue VU & Voltage Meter for Cars This great DIN mounting display features 3 analogue meters. It has 2 x VU meters, which require a line level throughput to your head unit, and 1 x voltage meter, so you can always keep an eye on your car’s battery condition. The blue meters look great providing some old-school style relief from the digital meters we so commonly see. The case is standard 1u Cat. $ .95 DIN mount. QP-5035 See website for details. 89 Stereo Camcorder Microphone Shotgun Video Camera Microphone This high quality electret condenser Improve the sound quality of your home microphone video recordings with this uni-directional is designed to pickup sounds from a long distance away, as well as close up (with the flick of a stereo microphone. Great in many switch). See website for details.. environments, see website for details. Was $59.95 SAVE Was $49.95 $10 Cat. VE $ .95 SA Cat. $ .95 AM-4085 0 $1 AM-4083 39 49 MASSIVE METER REDUCTIONS See website for all details and specifications. Mini Low Cost Digital Multimeter •10A Current •Transistor Test •Limited Quantity Was $11.95 Low Cost DMM Data Hold DMM Backlit Temp DMM •10A Current •Transistor Test •Diode Test Was $14.95 •10A Current •Low Battery Indicator •Includes Holster Was $19.95 •Professional Look •Continuity Tester •Data Hold Was $29.95 SAVE $5 SAVE $5 Cat. QM-1495 6.95 $ 9.95 Cat. QM-1500 Low Cost Auto Ranging Digital Multimeter $ 24.95 Cat. $ QM-1526 Inductance DMM •Temperature •Capacitance •Auto Power Off Was $59.95 •Capacitance •Temperature •Transistor Tester Was $59.95 SAVE $10 SAVE $10 SAVE $5 25 49.95 34.95 Cat. $ QM-1320 Cat. $ QM-1535 •Capacitance •Frequency •Temperature •Data Hold •Backlight •Limited Quantity Was $79.95 Cat. $ .95 QM-1450 Cat. $ QM-1445 Auto-Ranging DMM Extra Large Digit Digital Multimeter SAVE $20 •Capacitance •Bargraph •Data Hold •Frequency •Continuity Tester •Transistor Tester Was $79.95 •Data Hold •Relative Measurement •Duty Cycle •Frequency •40M Ohm Resistance •Capacitance Was $89.95 SAVE $20 Cat. $ QM-1530 Autoranging RS-232 Digital Multimeter •4000 Count •Cat III 1000V •RS-232 Interface •Includes Temperature Probe •Includes Holster Was $169.95 DIGITECH Cat. $ .95 QM-1460 139 SAVE $30 10MHz Single Trace Budget CRO with Probe This unit is ideal for the professional or dedicated enthusiast, who only needs the occasional use of a CRO. It features a powdercoated steel case, 75mm CRT with 5mm square graticule and more. It has standard sensitivity of 5mV/DIV to 5V/DIV,with sweep from 0.1µS/DIV to 0.1S/DIV. See website for details. Was $379 SAVE Cat. $ $50 QC-1910 49.95 True RMS Auto-Ranging DMM 59.95 59 329 14.95 $ Frequency DMM •Capacitance •Relative Measurement •Frequency Was $39.95 •Peak Hold •Data Hold •Transistor Tester Was $29.95 Cat. $ .95 QM-1534 •Duty Cycle •Frequency •Dual Temperature •Capacitance •Continuity Buzzer •Diode Tester •Backlit LCD Cat. QM-1520 Auto Ranging DMM SAVE $4 SAVE $5 SAVE $5 SAVE $10.95 79.00 Cat. $ QM-1536 Protek 506 - Auto Ranging Computer Connect •Dual Display •True RMS •Capacitance •Continuity •Auto Power Off •Bargraph •Relative Measurement •Data Hold •Inductance •4000 Count •20A Current •Includes •Logic Tester Temperature •10MHz Probe Frequency •Includes Holster •Temperature •Diode Tester Was $299 •Recording (Min, Max, Avg) SAVE $69.05 .95 229 Cat. $ QM-1290 10MHz Velleman Handheld LCD Oscilloscope The Velleman Handheld Oscilloscope is a complete, portable unit, all at the size and cost of a good multimeter. Features include a high contrast LCD with wide viewing angle, full automatic setup, true RMS and sound level measurement. See our website for full details. Was $349 SAVE Cat. $ $40 QC-1916 309 www.jaycar.com.au Online Internet Ordering 1500W (2500W Surge) Electrically Isolated 24VDC to 230VAC Pure Sine Wave Inverter With an input of 24V DC, this inverter can be used in trucks, buses, semi trailers or fixed installation 24V battery banks. It bristles with protection circuits including battery over/under voltage alarm, over temperature alarm, overload and short circuit protection and much more. See our 2004 Cat. catalogue or website for details. Note: MI-5089 Remote control sold separately Cat MI-5086. 75Ω Inline Fixed Attenuators Fixed attenuators are a handy way to resolve ghosting and reflections caused by too higher signal F type shown strength created by RF or Video signals. BNC, F-Type and RCA fixed attenuators will address this problem. •Bandwidth: 5MHz to 1GHz. •All are inline (socket to plug). -3dB RCA Cat. LT-3051 -3dB BNC Cat. LT-3053 -6dB BNC Cat. LT-3055 -12dB BNC Cat. LT-3057 -3dB F Cat. LT-3052 -6dB F Cat. LT-3054 -12dB F Cat. LT-3056 7 All Types (Each) $ .95 F Type 75Ω DC Blocking Module DC Blocking modules stop the DC voltages from powered RF Amplifiers travelling into TV sets or other devices. It is a low cost protection for expensive TV sets or equipment. Cat. $ .95 LT-3070 16 Stereo RF Modulator for Audio/Video This stereo modulator converts a Video, Left and Right Audio signal to an RF or 'Antenna' type signal to connect directly into a TV which only has a TV aerial socket. This is commonly required for older TV sets.•Channels 0 and 1. Mono version shown •Requires 12VDC <at> 100mA. Cat. $ .95 •Use Plugpack MP-3002 LM-3873 19 Professional Quality Earth First Gold RCA Connectors "Earth First" RCA connectors use a retractable earth sleeve which ensures the earth path is connected before the signal. Very important when working with powered equipment. Pro quality with gold plating. Red Cat. PP-0222 Each Black Cat. PP-0224 Colour 18 0 0 0 2 2 8 8 8 Freecall For Orders 1.5 - 30VDC <at> 1A Switchmode Lab Power Supply 999 $ Lascar has taken its panel meter and power supply expertise and fused it together to produce this stylish compact switchmode power supply. It features a backlit dual 3 digit LCD display, which indicates output voltage and current. Cat. $ MP-3095 199 3-28V Wireless Automotive Voltage Tester This professional grade wireless voltage tester is designed for use on modern cars. It will light up, buzz, and vibrate when positive voltage is detected. It is safe to use with ECU’s, air bags, sensors, transducers etc. Cat. $ .95 QP-2212 29 Neon Spark Plug Tester Have you ever found yourself paying a motor mechanic to rectify a faulty spark plug because you did not know what the problem was? Well now you can test this yourself by using this spark plug tester. Ideal for the mechanic, auto electrician, auto club member or just the average motorist. 5.95 Cat. QP-2264 $ 6.95 100:1 Oscilloscope Probe Kit Suitable for use with all CRO’s in our range. Attenuation Ratio: 100:1. Bandwidth: DC to 250MHz. 29 90-300VAC/DC Voltage Tester This small circuit tester allows you to test for live circuits between 90V to 300V. A neon light illuminates to indicate voltage detection. It also has a pocket clip to prevent it from falling out while getting into those awkward places. Cat. $ .95 QP-2240 3 Stud/Metal/Volt Tester This easy to use 3-in-1 detector can show the location of metal, voltage, and wooden studs behind walls, plywood, or flooring up to 3/4 inch thick. It is a very versatile and portable tool that fits into the pocket of a renovator, builder or just the average handyman ready for use. Cat. $ .95 QP-2282 Surface Mount Rework Flux Pen This SMD Rework Flux is a quick drying, no-clean flux for use when removing or replacing surface mount components. Handy 12ml pen with chisel tip. Cat. $ .95 NS-3035 12 59.95 Cat. $ QC-1903 SPDT 60A Horn Relay This relay is ideal for any high current switching application eg, Amplifiers, ignition cutout, transmitters, car spotlights, and more. 12V nominal coil voltage. Cat. $ .95 SY-4074 8 These handy cable tie mounts make it possible to use cable ties in runs along walls and ceilings made of brick or concrete. UL 94V-2 approved Nylon. Cat. Pk 20 $ .50 HP-0795 Pk 100 This handy set will compliment any workshop. It features a compact design so you can add it to your existing tool case without losing too much space. The metal storage case is strong and durable, ideal for people on move. See 2004 Cat. $ .95 catalogue/website TD-2029 for full details 29 Concrete Cable Tie Mounts $ 23 Piece Ratchet and Bit Set 4 18.95 Cat. $ HP-0796 BLOWER FANS 76mm x 75mm 12VDC Blower Fan Standard Air Volume: 0.27(m3/min), 9.5(CFM) Bearing System: Sleeve Speed: 2,700 RPM Current: 200mA Cat. $ .95 YX-2530 17 97mm x 94mm 12V DC Blower Fan Ball Bearing Air Volume: 0.74 (m3/min), 26(CFM) Noise: 51dB(A) Bearing System: Ball Speed: 3,600 RPM Current: 860mA Cat. $ .95 YX-2532 29 Luxeon Star LED Driver Kit Ref: Silicon Chip May 2004 This great kit allows you to power 1W, 3W, or 5W Luxeon Star LEDs from a 12V power source. This means that you can take advantage of what these super high power devices have to offer, and utilise them in your car, boat, or caravan. Kit supplied with PCB, and all electronic components. Cat. $ .95 KC-5389 29 AC/DC Current Clamp Meter Kit for DMM’s Ref: Silicon Chip Sept 2003. A great low cost alternative to expensive current clamp meters. It uses a simple hall effect sensor and iron ring core setup and connects to your digital multimeter. It will measure AC and DC current and has a calibration dial to allow for any magnetising of the core. Much cheaper than pre-built units. Kit supplied with PCB, clamp, case, silkscreened front panel and all electronic components. WAS $34.95 Cat. $ .95 KC-5368 26 Studio 350 - High Power Amplifier Kit Ref: Silicon Chip Jan/Feb 2004. This fantastic new amplifier kit will deliver 200WRMS into a 8Ω load, or 350WRMS into a 4Ω load. It is super quiet, with a signal to noise ratio of 125dB(A) at full 8Ω power. Harmonic distortion is a fantastic 0.002% and frequency response is almost flat between 15Hz and 60kHz. Kit supplied in short form including PCB & all electronic components. Kit requires heatsink and +/-70V power supply. See in store for our great deal on power supply components for Cat. $ KC-5372 this kit! 175 YOUR LOCAL JAYCAR STORE NEW SOUTH WALES Albury •Ph (02) 6021 6788 Bankstown •Ph (02) 9709 2822 Bondi Junction •Ph (02) 9369 3899 Brookvale •Ph (02) 9905 4130 Campbelltown •Ph (02) 4620 7155 Erina •Ph (02) 4365 3433 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 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 NEW ZEALAND 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 Serial PIC Programmer Kit SAVE $8 Valve Audio Pre-Amp Kit 89 Valve Preamp Add-On Kit Ref: Silicon Chip November 2003. Add to KC-5370 for a stereo valve preamp. Powered from KC-5370, so no extra power is required. Kit supplied with PCB, valve and all electronic components. 27.95 "Quick Brake" - Emergency Brake Light Trigger Kit Ref: Silicon Chip March 2004. Now you can put on your brake lights even before you touch the brake pedal! It triggers when you rapidly lift your foot off the throttle, as you would to put it on the brake, so following motorists are warned that you're stopping much earlier! Works with standard throttle position sensors. Kit supplied supplied with PCB, wire and all electronic components. 24.95 59.95 Cat. $ KC-5371 50MHz Frequency Meter Kit Ref: Silicon Chip Oct ‘03. Very accurate, large 8 digit display. Kit supplied with PCB, laser cut silk screened panel, preprogrammed micro, and all specified electronic components. Cat. $ .95 KC-5369 Ref: Silicon Chip April 2004. We have sold thousands of mixture display kits over the years, providing many enthusiasts with a great meter for their car. This new version incorporates new and improved features such as better circuit protection, a dimming function for night driving, and an emergency lean-out alarm. Supplied with PCB & all electronic components. Car must be fitted with air flow and EGO sensors. Cat. $ KC-5374 $ 44 Ref: Silicon Chip Nov 2003. AT LAST! A valve based preamp kit! It uses a 12AX7 valve and offers excellent performance. Kit supplied with PCBs, case, valve, ferrite cores, bobbin and clips and all electronic components. Requires 12VDC <at> 250mA. Cat. $ .95 These include all KC-5370 components for the Hi-Fi conversion described in Feb Silicon Chip ‘Smart’ Fuel Mixture Display Kit for Cars Cat. KC-5373 Ref: Silicon Chip Sept. 2003. This great little programmer features a portable, robust design and has provisions for In Circuit Serial Programming (ICSP) for micros which support this programming feature. This avoids the need to unplug a PIC from it's circuit to make and test changes to the code. It simply connects to your PC's serial port. Kit supplied with PCB and all electronic components. ZIF socket, serial cable. Battery not supplied. Cat. $ .95 KC-5367 69 LO O K I N G F O R A N O LD K I T ? If you are, we may have it in our Kit Back Catalogue. The 'Kit Back Catalogue' range is listed on the Jaycar website (under Kits & Projects) and can only be purchased via the website “www.jaycar.com.au” or Techstore (i.e. not the Jaycar stores). Deluxe Solar Education Kit A series of experiments to acquire a basic knowledge of solar energy. Includes Solar cell, musical unit, plastic lamp, motor accessories and plastic adaptors. 24.95 Cat. $ KJ-6694 MAIL ORDERS - FREE POST TO: Reply Paid 6424. Jaycar Techstore Mail Orders. PO Box 6424, Silverwater NSW 1811 PRICES VALID TO 31ST MAY 2004 www.jaycar.com.au Online Internet Ordering PRODUCT SHOWCASE Knock, Knock . . . Who’s There . . . It’s Me . . . Every now and then, a product comes along which is so simple, yet so clever in solving a problem, that you wonder why it hasn’t been thought of before. Knock-In-Key is such a product. It’s sole purpose is to ensure you are never locked out of your car again (a staggering 950,000 people last year alone in Australia are estimated to have locked their keys in their car). With no external devices or traditional keys, Knock-In-Key allows you to operate the vehicle’s central door locks by simply knocking a predefined code on the vehicle’s glass or panel. Now you can throw away the coat hanger or packaging tape! And no more waiting around for an hour or more for road service to arrive. And if you happen to have broken your key off in the lock, you’re no longer in trouble. It’s a simple idea but not simplistic when it comes to security. Knock-In Key requires the user to pick their own sequence of 5 to 12 “knocks” (such as knock-knock-knock, knock-knock- knock-knock, knock). Knock the right combination and the doors unlock! It won’t allow simple combinations of more than two repeated numbers at a time and three failed attempts at the code will block the knock access to the vehicle for one hour. It also requires the user to input a new code after it has unlocked the doors in case anyone saw them enter. This all means that your vehicle’s security is not compromised by this ingenious little helper. The unit measures just 52 x 37 x 20mm and features easy installation – well within the capabilities of anyone with auto electrical and/or traditional car security knowledge. With a recommended retail price of $129.00, Knock-In-Key is being currently being launched in NSW with a national launch to follow soon. Dealer enquiries are welcome. Contact: Aggeggi 64 Beresford Ave, Greenacre NSW 2019 Tel: (02) 9707 4933 Fax: (02) 9707 4805 Website: www.knockinkey.com.au Computer books for the annually challenged We’ve lost count of the number of times here at SILICON CHIP we talk to older people about using computers and the internet and the response is “Oh, I’m too old to start learning those things” or somesuch nonsense. Well now there really is no excuse with these two new titles from Jaycar: “The Internet for the Older Generation” and “Digital Photography and Computers of the Older Generation” are written especially for the over 50s (not that there aren't a few young’uns who’d get a lot from them as well!). They feature easy-to-understand language and large, clear type. Both are around 200 pages and have a recommended retail price of $29.95. They’re available at all Jaycar Electronics stores. If you’ve never wanted to get into PCs – here’s your big chance! Contact: Jaycar Electronics PO Box 6424, Silverwater NSW 1811. Tel: (02) 9741 8555 Fax: (02) 9741 8500 Website: www.jaycar.com.au 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 siliconchip.com.au May 2004 53 Two new stores makes 35 for Jaycar Electronics As part of an ongoing expansion program, Jaycar Electronics has opened two new stores, one in Taren Point (southern Sydney) and another in Albury (on the NSW/Victorian border), bringing the total number of Jaycar stores to 35 Australia-wide. Jaycar brings to the areas many years of retail experience and a proven product range covering home and car alarm systems, test equipment, video surveillance, car audio, electrical & electronic tools, wire, cable and accessories along with an extensive range of electronic equipment and kits. Each store will employ up to 5 local staff in a combination of full time and casual positions. The Taren Point store is located at 49A Captain Cook Drive (Ph 95317033) and is open 7 days. The Albury store is at 565 Hume Street (Ph 6021-6788). Contact: Jaycar Electronics PO Box 6424, Silverwater NSW 1811. Tel: (02) 9741 8555 Fax: (02) 9741 8500 Website: www.jaycar.com.au Two new Nikon digitals for advanced photographers Maxwell Optical Industries P/L, Australian Nikon Imaging Company distributor, has announced the immediate local availability of two high-end digital cameras - the D70 digital SLR and the Coolpix 8700, Nikon’s flagship 8 Megapixel digital compact. Nikon D70 Digital SLR At under $2000 (body only), the Nikon D70 employs the Nikon DX format 6.1 megapixel sensor and Nikon F lens mount design. This maintains seamless compatibility with all AF Nikkor lenses while allowing photographers to take full advantage of high quality DX Nikkor lenses designed exclusively for Nikon’s D-series digital SLR cameras. Developed concurrently and designed as a perfect match for daily use with the D70 and to deliver top performance and outstanding value, the new AF-S DX Zoom-Nikkor 1870mm f/3.5-4.5G IF-ED is also ready to join the lineup. The D70 is also backwards-compatible with most Nikkor lenses, meaning that owners of Nikon film SLRs can use their existing optics with the new digital model. The Nikon D70 body is priced at $1999 and $2299 with the new ZoomNikkor 18 - 70mm lens. Nikon Coolpix 8700 With an impressive 8.0 effective megapixels and a powerful 8x zoom lens, the COOLPIX 8700 is positioned as Nikon’s flagship digital compact The camera primarily targets users 54 Silicon Chip Adding USB support Elexol’s low cost USBIO24 module is one of the fastest ways you can add input and output USB support to any device. These development modules provide an interface between the USB port of a PC and external circuitry. The module features 24 5V level signal lines individually programmable as input or output as well as capabilities for further expansion via the expansion port. As the module connects to the USB port, multiple modules can be connected to a single PC by the use of a USB hub or hubs. Each module features a serial number and the PC can identify each module uniquely allowing for multiple modules to be connected for a single application. The outputs of the module are able to source or sink up to 30mA per I/O. Contact: Elexol Pty Ltd PO Box 5972, GCMC, Bundall, Qld 4217. Tel: (07) 5574 3988 Fax: (07) 5574 3833 Website: www.elexol.com who already explore advanced forms of photographic expression, but are looking for something more in a compact digital camera. The professional-quality 8x ZoomNikkor has 8.9 - 71.2mm focal range (equivalent to 35 - 280mm in 35mm format), the lens incorporates two ED (Extra-low Dispersion) lens elements to minimize chromatic aberration and deliver clear and crisp image reproduction. The Coolpix 8700 has an RRP of $1999. Both the D70 and 8700 are available at leading camera retailers. FOOTNOTE: SILICON CHIP has had the chance to play with a Nikon D70 over the past two weeks. We'll tell you all about it in the June issue! Adelaide electronics suppliers merge Adelaide-based Tytronics and Tekelek have merged their businesses to be known as Tekstream. The new organisation plans on becoming a major competitor in the specialist electronics service sector. Tekelek was Australia’s largest producer of advanced electronic controls for air-conditioners and heaters, supplying industry leaders such as Carrier, Honeywell, Climate Technologies and Seeley International, while Tytronics was also involved in the HVAC market and is a global leader in electronic gas ignition systems, with wide experience in contract manufacturing and supply services. Contact: Contact: Locked Bag 2055, Lidcombe NSW 1825. Tel: (02) 8748 5200 Fax: (02) 8748 5220 Website: www.maxwell.com.au PO Box 2220 Port Adelaide SA 5015 Tel: (08) 8268 5400 Fax: (08) 8268 2503 Website: www.tytronics.com.au Maxwell Optical Industries Pty Ltd Tytronics/Tekstream siliconchip.com.au A look inside Altronics new Sydney Distribution Centre Back in the January 2004 issue we mentioned that Altronics Distributors were opening a new distribution centre in Auburn, in Sydney's western suburbs, to better service the company’s Easter States customers. The new centre was opened amid much fanfare and celebration on February 27 and we went on the Cook’s Tour, snapping some shots of this modern facility as we went. The new warehouse (above and below) was designed for maximum efficiency and speed in the movement of goods. Service hasn’t been forgotten, with a service centre able to tackle warranty and general service work. The retail centre is also state-of-theart, with superbly lit shelves to make component selection easy and certain. The full range of Altronics catalog products are carried in the retail store. COMING NEXT MONTH . . .* “Open Sesame” RFID Wot? What Watts? much power are you really using? Build Door Security Module How this handy energy meter and you'll probably be Tired of fumbling around in the dark for your keys? Can’t surprised. If you're wanting to save energy (and find the keyhole on a moonless night? Or perhaps you’re power bills) this project will be one of the best injust irritated by vestments having to punch in of the year. a code each time Multi-funcyou want to arm or tion digital disarm your security readout will system. End all these little tell you usannoyances and age, actual more with the wave power cost of your hand and our and much modern-as-tomorrow more. RFID Security Module! * These articles are amongst those planned for publication in the June issue of SILICON CHIP siliconchip.com.au May 2004 55 Hot-Swappable SATA removable HDD kit The simplest way to make sure all your data is safe from theft or fire is to take it with you. The easiest way to do this is with a mobile HDD rack. Serial ATA Hard Drives are now available and you can take advantage of this extra speed while keeping your data portable. With no drivers required, the hard drive appears as if it is plugged normally into the motherboard. Hot-swapping with these cases has native support in Windows 98/SE/ME/2K/XP and Linux. The case itself is made out of aluminium, this gives the drive extra protection from the bumps and knocks of everyday life. Contact: Microgram Computers 1/14 Bon Mace Close, Berkeley Vale, NSW 2261 Tel: (02) 4387 8444 Freefax: 1800 625 777 Website: www.mgram.com.au CASIO enters data projector market CASIO, a familiar name in office technology products, has launched two new high-luminosity mobile projector models (XJ-350 and XJ-450) in its entry into the competitive data projector market. To complete this new line, CASIO also introduced a new 4-megapixel CCD multi-functional document copy stand (YC-400). The XJ-350 and XJ450 mobile projectors employ an original new condenser lens and light source lamp that deliver high-brightness images that can be clearly viewed under normal lighting conditions, in a compact, highly portable configuration. The XJ-350 delivers an amazing 2200 ANSI lumens from a minuscule 230mm x 55mm x 171mm 56 Silicon Chip Maxwell’s new 350F ultracapacitor No, that’s not a misprint. Three hundred and fifty FARADS! Using industry-standard “D” cell battery dimensions, Maxwell’s new BOOSTCAP BCAP0350 is a big step forward in ultracapacitors. The 350F, 2.5V device provides system designers a lower-cost, highly reliable, and standard-sized energy storage and power delivery component for seamless and rapid integration in a variety of applications. It is the first in a series of new ultracapacitors to be standardized on battery-sizing to drive down costs and ease integration of the technology. As with all BOOSTCAP ultracapacitors, the BCAP0350 can supply bursts of high power and recharges rapidly from any energy source over hundreds of thousands of cycles without significant performance degradation. The BCAP0350 offers particular benefit to the transportation market where designers can us it to power initial acceleration, operate electrical subsystems and recapture energy from braking for cleaner, more fuel-efficient hybrid electric/internal combustion buses, trucks and automobiles. For industrial systems, the BCAP0350 provides a simple, solid state, highly reliable solution to buffer short-term mismatches between the power available and the power required. Contact: Maxwell USA 9244 Balboa Ave, San Diego CA 92123 Tel: (0011) 1 858 503 3300 Fax: (00011) 1 858 503 3301 Website: www.maxwell.com Tektronix MyScope custom control windows With MyScope custom control windows and intuitive context-sensitive right-click menus, the TDS5000B Series of DPO oscilloscopes from Tektronix is said to be the easiest to use, most customizable midrange oscilloscope available. It has standard built-in spectral analysis, equation editor and histogram statistics. The TDS5000 series captures greater than 100,000 waveforms per second. It has a multi-view zoom with lock and scroll and has 4M/2M/1M standard record length on 1/2/4 channels (optional 16M/8M/4M). size configuration, while the XJ450 with its letter-sized footprint delivers 2800 ANSI lumens. Both models come with a 2X optical zoom lens, by far the highest zoom level available for any micro-portable data projector, which makes it possible to project onto a screen as close as 0.8 meters. This means that these projectors can be used with ease in environments where meeting space is limited. The new YC-400 Document Copy Stand & Digital Camera has a high-resolution 4-megapixel CCD and an automatic adjustment feature that automatically corrects the positioning between the camera and subject so that it appears squarely on the screen. It can be used for instantly projecting images of white board contents, 3-dimensional objects, as a digital scanner and as a fully functioning, stand-alone digital camera. Contact: NewTek Sales 11 Lyon Park Rd, North Ryde NSW 2113 Tel: (02) 9888 0100 Fax: (02) 9888 0125 Website: www.newteksales.com Contact: Shriro Australia 23-27 Chaplin Dve, Lane Cove NSW 2066 Tel: (02) 9415 5040 Fax: (02) 9415 5044 Website: www.casio.com.au siliconchip.com.au SILICON CHIP WebLINK How many times have you wanted to access a company’s website but cannot remember their site name? Here's an exciting new concept from SILICON CHIP: you can access any of these organisations instantly by going to the SILICON CHIP website (www.siliconchip.com.au), clicking on WebLINK and then on the website graphic of the company you’re looking for. It’s that simple. No longer do you have to wade through search engines or look through pages of indexes – just point’n’click and the site you want will open! Your company or business can be a part of SILICON CHIP’s WebLINK . For one low rate you receive a printed entry each month on the SILICON CHIP WebLINK page with your home page graphic, company name, phone, fax and site details plus up to 50 words of description– and this is repeated on the WebLINK page on the SILICON CHIP website with the link of your choice active. Get those extra hits on your site from the right people in the electronics industry – the people who make decisions to buy your products. Call SILICON CHIP today on (02) 9979 5644 We specialise in providing a range of Low Power Radio solutions for OEM’s to incorporate in their wireless technology based products. The innovative range includes products from MK Consultants, the world-renowned specialist manufacturer. TeleLink Communications Tel:(07) 4934 0413 Fax: (07) 4934 0311 WebLINK: telelink.com.au BitScope is an Open Design Digital Oscilloscope and Logic Analyser. PC software drives BitScope via USB, Ethernet or RS232 to create a powerful Virtual Instrument. BitScope is available built and tested or in kit form. Extensive technical details are available on the website. Great for hobbyists, university labs and industry. BitScope Designs Designs BitScope Contact: sales<at>bitscope.com Contact: sales<at>bitscope.com WebLINK: bitscope.com WebLINK: bitscope.com We endeavour to provide a range of technical books of interest to the Radio Amateur as well as electronics enthusiasts, at competitive prices. Special discounts are offered to WIA members. We are the only bookshop of this type in Australia. Wireless Institute of Australia (VK2) siliconchip.com.au Tel:(02) 9689 2417 Fax: (02) 9633 1525 WebLINK: wiansw.org.au/bookshop/ · Hifi upgrades & modification products - jitter reduction and output stage improvement. · Danish high-end hifi kits - including pre- amps, phono, power amps & accessories. · Speaker drivers including Danish Flex Units plus a range of accessories. Soundlabs Soundlabs Group Group JED designs and manufactures a range of single board computers (based on Wilke Tiger and Atmel AVR), as well as LCD displays and analog and digital I/O for PCs and controllers. JED also makes a PC PROM programmer and RS232/RS485 converters. Jed Microprocessors Pty Ltd Tel: (03) 9762 3588 Fax: (03) 9762 5499 WebLINK: jedmicro.com.au 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°. Av-COMM Pty Ltd Tel:(02) 9939 4377 Fax: (02) 9939 4376 Tel:(02) WebLINK: avcomm.com.au WebLINK: avcomm.com.au A 100% Australian owned company supplying frequency control products to the highest international standards: filters, DIL’s, voltage, temperature compensated and oven controlled oscillators, monolithic and discrete filters and ceramic filters and resonators. Our website is updated daily, with over 5,500 products available through our secure online ordering facility. Features include semiconductor data sheets, media releases, software downloads, and much more. Hy-Q International Pty Ltd JAYCAR JAYCAR ELECTRONICS ELECTRONICS Tel: Tel: 1800 1800 022 022 888 888 Syd: (02) 4627-8766 Melb: (03) 9859-0388 Syd: (02) 9660-1228 Melb: (03) 9859-0388 Tel:(03) 9562-8222 Fax: (03) 9562 9009 WebLINK: www.hy-q.com.au WebLINK: www.jaycar.com.au WebLINK: PIC chip specialists – microEngineering Labs and others. Easy to learn, easy to use, sophisticated CPU based controllers & peripherals. RCS Radio has available EVERY PC Board ever published in SILICON CHIP, EA, ETI and AEM (copyrighted boards excepted). Many late boards are available ex stock, others can be made to order within a few days.Custom & production boards too! For everything in radio control for aircraft, model boats and planes, etc. We also carry an extensive range of model flight control modules including GPS, altitude and speed, interfaces, autopilot and groundstation controllers. More info on our website! WebLINK: WebLINK:soundlabsgroup.com.au soundlabsgroup.com.au See our website for new range of ATOM products! MicroZed Computers Tel: (02) 6772 2777 Fax: (02) 6772 8987 WebLINK: microzed.com.au Silvertone Electronics RCS Radio Tel:(07) Fax:(02) (07)4639 1275 Tel: (02) 4639 9738 1100 0330 Fax: 9738 0334 WebLINK: www.silvertone.com.au WebLINK: cia.com.au/rcsradio Silvertone Silvertone Electronics Electronics M ay 2004 57 Tel:(07) 4639 1100 Tel/Fax: (02)Fax: 9533(07)4639 3517 1275 WebLINK: www.silvertone.com.au WebLINK: silvertone.com.au The photo at left shows the completed power supply module. Position the inductor (L1) so that it’s well clear of surrounding components and secure it to the PC board using small cable ties. At right is a 5W Luxeon star LED, shown about 50% larger than actual size. STARPOWER High-efficiency supply for Luxeon Star LEDs Based on a switching regulator IC, this simple project is just the shot for powering 1W to 5W ultrabright Luxeon Star LEDs. It’s easy to build, runs off 12V DC and can be easily tailored to suit your requirements. By PETER SMITH B ACK IN THE December 2003 issue, we presented a simple linear power supply for powering 1W Luxeon Star LEDs from a 12V supply. Predictably, we’ve already received requests for a version that will drive the newer, brighter 3W Stars. In addition, many constructors want a higher efficiency supply for use in boats, caravans and cars. This new design fits the bill and includes low battery cutout as well. Unlike the original design, which is based on a linear regulator, this new supply employs a step-down switching regulator. The advantages of this method include much improved efficiency and significantly reduced heat generation. In fact, when driving a single 3W Star, this supply is at least twice as ef58 Silicon Chip ficient as a linear supply or simple current-limiting resistor. Obviously, this means longer battery life. Lower heat generation also means that you can build the supply into a case without the need for additional heatsinking. The project can be powered from any 12V DC (nominal) supply and can be set up to source 350mA, 700mA or 1000mA of regulated current to suit all of the Luxeon Star LED range. Block diagram The circuit is based around a Motorola MC34063 DC-DC converter IC. This chip contains all of the functions necessary to construct a complete low-power step-down switchmode regulator – see Fig.1. A simplified block diagram of the step-down regulator appears in Fig.2. Essentially, when transistor Q1 switches on, current though the series inductor (L1) increases with time, storing energy in its magnetic field. When Q1 is switched off, the magnetic field collapses and the energy is discharged into the output filter capacitor and load via diode D3. A free-running sawtooth oscillator in the MC34063 determines the maximum switch “on” time. The “on” time of the switch (Q1) versus its “off” time determines the fraction of the input voltage that appears at the output. IC1 controls the “on” time by monitoring the voltage on its feedback pin. As this voltage falls below 1.25V, Q1’s “on” time increases. Conversely, as the feedback voltage increases, the “on” time decreases. Complete “on” cycles are skipped if the feedback voltage remains above the 1.25V set point for the duration of the “on” period. In a typical implementation, the feedback pin would be connected to the output via a voltage divider to regulate the output voltage. However, our design regulates output current instead. Current through the LED(s) is sensed via resistor R1 and amplified by op amp IC2. The result is applied to the siliconchip.com.au Main Features • • • • • • Powers one or two 1W or 3W Stars, or a single 5W Star High efficiency for minimum battery drain Low battery cutout (11.5V) Input polarity & transient protected Output short-circuit protected Ideal for use in boats, caravans & cars feedback pin of IC1 via a trimpot, allowing accurate current adjustment. Simply put, the output current is regulated by maintaining the voltage across the sense resistor at about 100mV. In practice, the actual sense voltage depends on the value of R1 and the position of the trimpot. Fig.1: inside the MC34063 DC-DC Converter IC. It contains the circuitry to build a step-up, step-down or inverting switching regulator. Circuit details The complete circuit diagram appears in Fig.3. Following the circuit from the input voltage side, diode D1 provides reverse-polarity protection. A Schottky type is used here to reduce voltage losses. Next, a 24V zener diode (ZD1) clamps input transients to less than the maximum voltage rating of downstream components. A 470µF capacitor then filters the input and provides a low-impedance source for the highfrequency switching circuitry. As described above, transistor Q1 acts as a switch in series with the inductor (L1). A Zetex low VCESAT (collector-emitter saturation voltage) type was chosen for Q1 to improve efficiency and reduce heat dissipation. The performance of the switching circuit is further enhanced by a turnoff speed-up circuit, which operates as follows: During an “on” cycle, transistors internal to the MC34063 switch on, bringing pins 1 & 8 towards ground. This forward-biases the base-emitter junction of Q1 via D4 & L2, switching the transistor on. When the “on” cycle ends, pins 1 & 8 go open circuit and the current through L2 abruptly ceases. The magnetic field around L2 collapses, generating a voltage of opposite polarity to the charge voltage. This forward-biases the baseemitter junction of Q2, momentarily switching it on and connecting the siliconchip.com.au Fig.2: the basic block diagram of the step-down switching regulator section. A fraction of the input voltage is transferred to the output under control of an MC34063 switching regulator IC. The LED current is regulated by sensing the voltage drop across a small series resistance (R1). base of Q1 to its emitter. This results in significantly faster turn-off of Q1 than is possible with a resistive pull-up alone. By minimising the transition time between saturation and turn-off, collector power dissipation, and therefore switching losses, are effectively reduced. When Q1 switches off, diode D3 provides a discharge path for the inductor (L1) to the output filter capacitor and load. Again, a Schottky diode is used for its fast switching and low forward voltage characteristics. Note that we’ve specified high current (3A) devices in order to withstand a continuous shortcircuit condition at the output. In normal operation, the peak current that flows in the transistor and inductor during each switching cycle is well within the limits of the component ratings. However, with an overloaded or short-circuited output, or with excessively high input voltages, the peak current could increase to destructive levels. To counteract this problem, IC1 senses peak current via a 0.15Ω resistor in series with the input. When the peak voltage across this resistor nears 330mV, the MC34063 progressively reduces the maximum “on” time of the switch by shortening the positive ramp of the oscillator. Current sensing A resistor in series with the LED provides a means of sensing output current. The voltage developed across R1 is amplified by one half of a dual op amp (IC2b), which is configured as a differential amplifier. With the resistor values shown, the sense voltage is amplified by a factor of 15 and applied to one end of VR1. Effectively, trimpot VR1 provides a May 2004 59 Fig.3: the complete circuit diagram for the power supply module. A low VCESAT transistor (Q1) is used for the switching circuit to minimise heat dissipation and improve efficiency. Output current is selectable in three ranges by choosing an appropriate value for R1. means of adjusting the voltage drop across R1. As the wiper is moved towards the top (clockwise), less voltage is required across R1 to satisfy the feedback loop, so the output current decreases. The opposite occurs when the wiper is moved downwards, attenuating the op amp’s output and thus increasing the output current. During construction, R1 is selected from Table 3 to suit the desired LED current. These values were chosen such that close to 100mV will be present across the resistor at the listed LED current level. It’s then just a matter of adjusting VR1 to get the precise current level. To reduce harmonics in the switching circuit, a novel scheme is used to “feed forward” a small portion of the switching signal into the feedback circuit. This is achieved with a 680pF capacitor between the ISENSE and FB pins. Low battery cutout IC2a is used as a simple voltage comparator for the low battery cutout circuit. It works as follows. Zener diode ZD2 provides a clean +7.5V supply for this op amp. This 7.5V rail is also divided in half by two 47kΩ resistors and to provide a reference voltage for the comparator on pin 3. Similarly, the power supply input voltage is divided down by 18kΩ and 9.1kΩ resistors and applied to the negative input (pin 2). When the voltage on pin 2 falls below that on pin 3 (corresponding to less than 11.5V at the supply input), the output swings towards the positive rail, forcing IC1’s feedback input above the 1.25V set point. This stops IC1 from switching and reduces the input current drain to quiescent levels (less than 10mA). A 1MΩ resistor between the op amp output (pin 1) and its positive input ensures fast switching and provides a few hundred millivolts of hysteresis. In addition, a 1µF capacitor at the inverting input filters out any momentary transients and ensures that 60 Silicon Chip siliconchip.com.au Parts List 1 PC board, code 11105041, 105mm x 60mm 1 powered iron toroid, 28 x 14 x 11mm (L1) (Jaycar LO-1244) 170cm (approx) 0.8mm enamelled copper wire 1 10µH RF choke (Altronics L-7022, Jaycar LF-1522) 2 2-way 5mm (or 5.08mm) terminal blocks (CON1, CON2) 1 2-way 2.54mm SIL header (JP1) 1 jumper shunt (JP1) 1 8-pin IC socket 2 M205 PC mount fuse clips 1 M205 3A slow blow fuse 4 M3 x 10mm tapped spacers 4 M3 x 6mm pan head screws 2 small cable ties 1 heatsink for 3W or 5W LEDs (see text) 1 2kΩ miniature horizontal trimpot (VR1) Semiconductors 1 MC34063 DC-DC converter (IC1) or 1 On Semiconductor (Motorola) the negative input remains below the positive input during power up. Note that despite this filtering, the LED will flash momentarily at power on and power off. This is because unlike the LM358 op amp, the MC34063 operates right down to 3V. Finally, a series diode (D10) and 7.5V zener diode (ZD3) connected between the output and the feedback circuits prevents the output voltage rising much above 9V if the LED is inadvertently disconnected. This helps to reduce the peak current flow that occurs if the output is reconnected with power applied. Construction The assembly is straightforward, with all the parts mounted on a PC board coded 11105041 and measuring 105 x 60mm. The parts are all installed on the board in the conventional manner except for switching transistor Q1, a surface-mount (SMT) device which is installed on the copper side. The first job is to mount Q1. Although this is an SMT device, it has relatively large pins with ample spacing that are easy to solder. siliconchip.com.au branded part 1 LM358 dual op-amp (IC2) 1 FZT1151A PNP transistor (Q1) (Farnell 935-499) 1 2N3904 NPN transistor (Q2) 2 1N5822 Schottky diodes (D1, D3) 1 1N4004 diode (D2) 3 1N4148 small signal diodes (D4 - D6) 1 24V 5W zener diode (ZD1) 2 7.5V 0.5W (or 1W) zener diodes (ZD2, ZD3) 1 or 2 1W or 3W Luxeon Star LEDs; or 1 5W Luxeon Star LED (see text) Capacitors 2 470µF 50V low-ESR PC electrolytic (Altronics R-6167) 1 100µF 50V low-ESR PC electrolytic (Altronics R-6127) 1 100µF 16V PC electrolytic 1 1µF 16V PC electrolytic 2 100nF 50V monolithic ceramic 1 1.2nF 50V ceramic disc (or polyester) 2 680pF 50V ceramic disc To install it, place the copper side of the board up and position Q1 precisely as shown on the overlay diagram (Fig.6) before soldering the leads. With Q1 in place, turn the board over and install the two wire links using 0.7mm tinned copper wire or similar. One of the links (shown dotted) goes underneath IC2, so it’s important that it goes in first! Next, install all the low-profile components, starting with the 0.25W resistors and diodes. All the diodes, including the zeners, are polarised 1 560pF 50V ceramic disc 1 330pF 50V ceramic disc Resistors (0.25W 1%) 1 1MΩ 2 4.7kΩ 2 47kΩ 1 3.6kΩ 1 18kΩ 4 1kΩ 2 15kΩ 1 750Ω 1 9.1kΩ 1 390Ω 1W 5% 2 0.15Ω 5W (or 3W) 5% (Farnell 347-2693) 1 0.1Ω 5W (or 3W) 5% 1 0.27Ω 5W (or 3W) 5% Additional resistors for testing 1 10Ω 5W 5% (350mA test) 1 4.7Ω 5W 5% (700mA test) 1 3.3Ω 5W 5% (1000mA test) Note: parts shown with a Farnell catalog number can be ordered on-line direct from Farnell at www.farnellinone.com.au or phone 1300 361 005. The 0.15Ω 5W resistors are also available from WES Components, phone (02) 9797 9866. devices and are installed with their banded ends oriented as shown. An IC socket can be installed for IC2. However, IC1 should be soldered directly to the board (no socket!) to eliminate the effects of contact resistance. Be sure to align the notched (pin 1) ends as indicated. All remaining components can now be installed except for the electrolytic capacitors. It’s easier to leave these until after the inductor (L1) is in place. Select appropriate values for C1 & R1 from Tables 3 & 4. It’s very impor- Fig.4: this scope shot shows the switching waveform present on the cathode of D3 (top trace) versus the MC34063’s on-board oscillator on pin 3 (bottom trace). Note that the switching frequency will vary significantly according to LED type and number and will not necessarily equal the oscillator frequency. May 2004 61 Table 2: Capacitor Codes Value 100nF 1.2nF 680pF 560pF 330pF wound using the specified toroidal core and about 170cm of 0.8mm enamelled copper wire. Play out the wire into a straight length, removing any kinks before you begin. It’s easier to wind one half at a time, so start by feeding about half of the wire through the centre of the core. Wind on the first half using firm even tension and keep the turns as close as possible without overlapping. Now repeat this procedure with the second half of the wire. In total, the core will accommodate 50 turns if there are no gaps between adjacent turns on the inside of the core. Now count the total number of turns. With a bit of luck, you should have 49 or 50 (one less is OK!). Trim and fashion the ends of the wire so that the assembly slips home easily into the holes in the PC board with a few millimetres protruding out the opposite side. Next, scrape the enamel off the ends of the wire, tin them and reposition the inductor on the PC board. Don’t solder the wires just yet though. It’s important to first attach the inductor to the board using small cable ties. Position the inductor so that it is well clear of surrounding components before tightening up the ties. That done, solder and trim the wire ends. Fig.5: follow this layout diagram when installing the parts on the PC board and don’t forget the link under IC2. Fig.6: the mounting details for transistor Q1. It’s soldered on the copper side of the board using a fine-tipped soldering iron. tant that these match your intended application (type of LED and one or two LEDs in series). The parts list includes all of these parts, so you will have an extra three ceramic capacitors μF Code EIA Code IEC Code 0.1µF 104 100n .0012µF 122 1n2 – 681 680p – 561 560p – 331 330p and two 5W (or 3W) resistors left over once assembly is complete. Winding the inductor The inductor (L1) must be hand- Table 1: Resistor Colour Codes  o o o o o o o o o o No. 1 2 1 2 1 2 1 4 1 1 62 Silicon Chip Value 1MΩ 47kΩ 18kΩ 15kΩ 9.1kΩ 4.7kΩ 3.6kΩ 1kΩ 750Ω 390Ω 5% 4-Band Code (1%) brown black green brown yellow violet orange brown brown grey orange brown brown green orange brown white brown red brown yellow violet red brown orange blue red brown brown black red brown violet green brown brown orange white brown gold 5-Band Code (1%) brown black black yellow brown yellow violet black red brown brown grey black red brown brown green black red brown white brown black brown brown yellow violet black brown brown orange blue black brown brown brown black black brown brown violet green black black brown not applicable siliconchip.com.au Finally, install all the electrolytic capacitors to complete the job. Take particular care with orientation – their positive leads must go in as indicated by the “+” markings on the overlay diagram. you may be able to hear a low level “squeal” coming from the inductor (L1). This is completely normal and is due to the harmonics caused by the gated oscillator architecture of the MC34063 switching regulator IC. Setup & testing Fault-finding Before connecting an LED to the output for the first time, the supply should be checked for correct operation. During the test, we’ll also set the output current to an initial value to suit the type of LEDs being used. The test involves inserting a 5W test resistor in the LED output terminals. The resistor value to use depends on the output current level selected during assembly. For 350mA of current, use a 10Ω test resistor, for 700mA a 4.7Ω value and 1000mA a 3.3Ω value. Don’t cut the resistor leads short. It should be screwed into the LED output terminal block and suspended in midair, such that it’s not in contact with anything; it will get very hot! With this in mind, the circuit should not be powered up for more than a few minutes with the test resistor in place. Remove the jumper shunt on JP1 if you installed it earlier and rotate VR1 fully clockwise. Connect a 12V DC (1A or higher) power source to the input terminals and power up. Monitor the voltage across R1 (not the test resistor) with your multimeter and adjust VR1 to get the desired current level. The correct sense voltage for each current level is listed in Table 3. For example, if you want 700mA for a 3W LED, you will have installed a 0.15Ω resistor for R1, so adjust VR1 to get a 105mV reading on your meter. If all checks out, you’re almost ready to go. Remove the test resistor and replace it with the LED leads. That done, power it up again and check that the voltage across R1 is as previously set. If necessary, readjust VR1 to get the listed reading. Note: the light output from these LEDs could damage your eyesight. Do not stare directly into the LED beam at close range! If you have a variable DC bench supply, you can also test the low battery cutout circuit by slowly reducing the input voltage. At about 11.5V, the LED should switch off. Remember to install the jumper shunt on JP1 to enable this function. Note: in a quiet environment, If your meter reads way off the mark and/or adjusting VR1 has no effect, then there is a fault on the board. Switch off and remove the test resistor, then power up again with nothing connected to the output. With your meter set to read volts, first measure between pins 1 & 8 of IC2. These are the op amp supply pins, so you should get close to 7.5V. If not, look for problems around ZD2 and its associated circuitry. Next, measure between pins 6 & 4 of IC1. Again, these are the supply pins of the IC but this time, expect about 0.3V less than the input voltage. If you have an oscilloscope, you can check that the oscillator in the MC34063 is working by examining the waveform on pin 3. You should see a clean sawtooth waveform like that shown in Fig.4. Assuming the above measurements are OK, then it’s back to basics. Examine the board closely for correct component placement and soldering defects, especially around IC1, IC2 and the 100µF 16V capacitor. It’s easy to siliconchip.com.au Bend and shape the ends of the winding so that the assembly slips easily into the holes in the PC board. This shot of the underside of L1 shows the general idea, although this core doesn’t have the full 50 turns! This larger-than-life size view shows how transistor Q1 is mounted on the underside of the PC board. Table 3: Selecting Resistor R1 LED Type LED Current R1 Sense Voltage 1W Star 350mA 0.27Ω 94.5mV 3W Star 700mA 0.15Ω 105mV 3W Star 1000mA 0.1Ω 100mV 5W Star 700mA 0.15Ω 105mV Table 4: Selecting Capacitor C1 LED Type No. of LEDs in Series Colour C1 1W Star 1 Red, Red-Orange, Amber 330pF 1W Star 2 Red, Red-Orange, Amber 680pF 1W Star 1 White, Green, Cyan, Blue, Royal Blue 560pF 1W Star 2 White, Green, Cyan, Blue, Royal Blue 1.2nF 3W Star 1 All 560pF 3W Star 2 All 1.2nF 5W Star 1 All 1.2nF May 2004 63 Where To Get Luxeon Stars Luxeon Star LEDs and the heatsinks mentioned in the text can be purchased from one or more of the following sources: (1). Alternative Technology Association, phone (03) 9388 9311, www.ata.org.au (2). Altronics, phone 1300 780 999, www.altronics.com.au (3). Jaycar Electronics, phone 1800 022 888, www.jaycar.com.au (4). Oatley Electronics, phone (02) 9584 3563, www.oatleye.com (5). Prime Electronics, phone (02) 9746 1211, www.prime-electronics.com.au Detailed technical information on Luxeon Star LEDs can be obtained from the Lumileds web site at www.lumileds.com get solder bridges between the closely spaced tracks in these areas. The completed power supply module can be mounted without an enclosure if a protected location is available. Alternatively, it can be housed in a UB3-sized “Jiffy” box for ruggedness. Jaycar Electronics has a range of flanged ABS boxes that would be ideal for the job. For marine applications, the entire assembly will need to be conformally coated or installed in a sealed enclosure to keep corrosion at bay. The power input and LED output wiring must be run using heavy-duty (7.5A) cable. We recommend no more than about 25cm of cable length between the power supply output and the LEDs. by far the easiest to use because of its relaxed heatsinking requirements. In fact, when operated in low ambient temperatures, no additional heatsinking is necessary for versions with board mounted optics (Star/O). However, in most real-world applications, a small heatsink will help to keep the LED junction temperature within specs, as well as prevent heat damage to the acrylic lens. This can often be as simple as a flat metal panel or the lid of a metal case, for example. Unlike the 1W types, the 3W & 5W Stars require careful attention to heatsinking, particularly when reliability and long service life are important. Despite this requirement, the excellent “lumens per buck” rating of the new 3W Stars definitely makes them worth a look. So how is the heatsink size determined? Let’s find out! Keeping your LEDs cool Heatsink basics This project can be used to power any of the 1W, 3W or 5W Luxeon Star range. Out of these, the 1W version is As with any power semiconductor device, we can calculate the required heatsink thermal resistance once we Mounting & wiring Fig.7: this is the full-size etching pattern for the PC board. 64 Silicon Chip A heatsink intended for one of the later model processors (such as the AMD Athlon) would be more suitable in high ambient temperatures and will extend LED life. Simply remove and discard the fan & retaining clip before drilling the mounting holes. Recycled heatsinks may have an old sticky heat transfer pad in the centre, which must be removed with solvent before attaching your LED. know the maximum junction temperature, ambient temperature and power dissipated. As only about 10% of the input power to the LED is emitted as light, it is disregarded in the following calculations. Assuming a nominal LED forward voltage of 3.6V, power dissipation can be found using Ohms law: PD = V/I = 3.6V/1A = 3.6W Using the absolute maximum LED junction temperature of 135°C and an ambient temperature of 25°C, the junction to ambient thermal resistance is: RTHJ-A = TJ - TA / PD = 135°C - 25°C / 3.6W = 30.5°C/W Next, subtract the junction to board resistance (RTHJ-B) listed in the datasheet to find the board to ambient thermal resistance. For most boardmounted Stars, this is 17°C/W: RTHB-A = RTHJ-A - RTHJ-B = 30.5°C/W - 17°C/W = 13.5°C/W The result is the maximum allowable heatsink resistance needed to keep the LED junction temperature at or below the maximum rating at 25°C ambient. The 48 x 48mm finned heatsink shown in the adjacent photo was originally designed for cooling Intel 486 and Motorola 68000 series microprocessors but works equally well siliconchip.com.au here. According to our rough calculations, it has a thermal resistance of about 8°C/W when operated in free air in the vertical position. So far, we’ve assumed operation up to the maximum LED junction temperature of 135°C. However, when operated continuously at this maximum, LED light output decreases quite markedly over time. To achieve the 20,000 hours at 50% lumen maintenance figure shown in the datasheets, Lumileds specifies a lower maximum junction temperature of 90°C. Reworking the figures for this lower temperature, you can see that a heatsink resistance of 1°C/W would be required. This would be difficult to implement in practice, necessitating a bulky heatsink, perhaps even with forced-air cooling. For maximum life with a realistic heatsink size, the answer is to drive the LEDs at reduced current. For this reason, Lumileds also characterises the 3W Star for operation at 700mA, stating lumen maintenance of 70% after 50,000 hours at the lower temperature figure. The maximum heatsink resistance needed in this case is 8.8°C/W at 25°C ambient, meaning our chosen heatsink barely makes the grade. If operation in the horizontal position is required or higher ambient temperatures are likely, then a lower resistance heatsink will be needed. The above information is also applicable to the 5W Star, although it’s life versus junction temperature figures are radically different to the 3W version. Note also that it’s rated for a maximum of 700mA forward current and has a higher forward voltage than the 3W device. Refer to the individual device datasheets for more information. To learn all about heatsinking, check out the “Thermal Design using Luxeon Power Light Sources” application brief, available from the Lumileds website at SC www.lumileds.com Silicon Chip Binders $12 REAL VALUE A T .95 PLUS P& P H S ILICON C HIP logo printed in gold-coloured lettering on spine & cover H Buy five and get them postage free! We mounted our 3W Star on a 48mm square heatsink pinched from an old 486 motherboard. Drill two 3mm mounting holes in line with the slot between the fins and then deburr the holes to obtain a smooth mounting surface. A thin smear of heatsink compound between surfaces will aid heat transfer. You’ll need to use nylon washers under the heads of the screws to prevent short circuits to the solder pads on the Star PC board. Don’t be tempted to run the 3W or 5W Stars without a heatsink – they’ll quickly self-destruct! Wide, narrow and elliptical beam lenses similar to that shown here can be fitted to suit most applications. siliconchip.com.au Available only in Australia. Buy five & get them postage free! 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. Silicon Chip Publications, PO Box 139, Collaroy 2097 May 2004 65 Wireless Parallel Port Low-cost design uses a 434MHz UHF data link Incorporating a UHF data link, this Wireless Parallel Port is just the shot for computer control of irrigation systems, solenoids, robots, lights or just about anything. It’s based on pre-built UHF radio modules and is low in cost. By NENAD STOJADINOVIC T HE NOVEMBER 2003 issue of SILICON CHIP included an article entitled “Smart Radio Modem for Microcontrollers”. This was basically a low-cost data link that could send up to 16 bytes of data at a time across the radio “ether” over a range of 150-200 metres. The project described here expands on that basic concept by serving up the received data in parallel format. This makes it much easier for the novice to use and opens up a world of ap- plications that were designed for the parallel port. Fig.1 shows the basic scheme for the Wireless Parallel Port. It’s based on a transmitter and receiver pair using Laipac brand 433.92MHz UHF modules, with PIC microcontrollers handling the “smarts”. As shown in Fig.1, the transmitter is exactly the same as used for the Smart Radio Modem. For those who haven’t seen it before, the modem transmitter can be driven by any microcontroller Fig.1: the basic scheme for the UHF Wireless Parallel Port. It’s based on pre-built UHF transmitter and receiver modules. 66 Silicon Chip such as a PICAXE, Stamp, etc. Alternatively, it can be attached to a computer COM port via an RS232-TTL adapter (also described in the November 2003 issue) and will accept the download of up to 16 bytes of data at a time. The downloaded data bytes are subsequently sent on their way by simply pulling the transmitter’s SEND pin low for a short period (eg, 0.25s). The modem receiver then outputs the data, giving the effect of a serial cable that can be up to 200m long. The parallel port receiver differs slightly in that it only receives and then outputs one byte of data per transmission. This data byte is latched on the output pins until the next byte comes along. Basic functions We will assume here that you have read the November 2003 article, so we won’t cover the same material again. If you don’t have a copy, it is available as a back issue for $8.80 (including postage). Basically, this unit is designed to be as easy to use as possible. For example, to transmit data to the Wireless Parallel Port using a communications program such as Hyperterminal, you simply send the number of the receiver pin that you want to turn on (ie, raise to +5V or logic “high”). You then briefly pull the SEND pin low on the transmitter module. Unfortunately, Hyperterminal (which comes standard with Windows) will not allow you to directly control the SEND pin (connected to the COM port’s RTS line), so using it requires a pushbutton switch between the SEND pin and ground. As a result, siliconchip.com.au Fig.2: this is the complete circuit for the receiving end of the UHF Wireless Parallel Port. PIC microcontroller IC1 receives data from the UHF receiver, decodes it and outputs the data (D0-D7) to pins 2-9 of a DB25F connector. LED1 flashes to indicate when data is being received. it’s more convenient to use a COM port test program which can drive the port directly. I use “Simple Term” which is available from www.ptronix.com. This program allows you to load the data, toggle the SEND (RTS) pin and watch the BUSY (DSR) pin all from the comfort of the computer screen – very convenient. Thus, to turn on pins 3, 4 & 5, you simply type in 345 (ie, no spaces) and toggle the SEND pin. In Simple Term, you type 345 in the blue bar, click Send and then change the RTS radio button to light green and back to dark. Sending 128 (for example) would then turn off the above pins and turn on pins 1, 2 & 8. Sending “0” turns all the pins off. Using a password The ability to use a password is a useful option with this unit and there are a couple of reasons why you might want to do this. If your neighbour has a similar unit, for example, the use siliconchip.com.au of a password will prevent interference between them. Alternatively, you might want to have a number of receivers, each responding to its own password. The password allowed is rudimentary. It simply consists of a single character but it does give you up to 256 different choices. To load a password, you simply type in “P” (without the quotes) and then the password; eg, P*. Note that you must use a capital P and the “learn link” must be in place on the board during this procedure – see Fig.2. Once that’s done, the receiver will only respond to commands prefaced by the password; eg, *145. To remove the password, just send the character “X” with the learn link in place. For advanced users Sending a byte to switch each of the pins is all very well but it can also be very useful to simply send a single byte that will be transferred to the port as binary data. To do this, simply send the “B” command followed by the binary data. Thus, B<01h> will set the port’s D0 pin high. Similarly, B<FFh> will set them all high. This function works in conjunction with a password if you have one in place. Circuit details The complete receiver circuit is shown in Fig 2. Apart from the UHF receiver module, it uses a PIC16F84 microcontroller (IC1) and a few other bits and pieces. The circuit essentially emulates a parallel port and outputs its data to D0-D7 (these are pins 2-9 on a standard DB25 connector). Pins 11, 12 & 13 of the DB25 connector are also connected to the microcontroller and may be used in future projects. In addition, an RX (received) data indicator is fitted, consisting of a LED connected to pin 13 via a 560Ω resistor. This LED May 2004 67 Fig.3: the PC board should only take you 30 minutes to assemble. Take care to ensure that the receiver module is correctly oriented – see photo. The PC board pattern at right is shown full size. lights and the pin goes high briefly when ever a valid data transmission has been received. The previously mentioned “learn link” is connected to pin 17 (RA0) of IC1. Fitting this link pulls pin 17 high (it’s normally pulled low via a 10kΩ resistor) and places the microcontroller in the “learn” mode. Parts List 1 PC board, code 07105041, 60 x 60mm 1 4MHz 3-pin ceramic resonator (CR1) 1 DB25 female PC-mount connector 1 18-pin IC socket 1 2-way connector 1 2-pin SIL header plus jumper shunt 1 8-pin straight SIL header 1165mm length of light-duty hookup wire Semiconductors 1 Laipac RLP-434 UHF receiver module 1 PIC16F84 programmed microcontroller (IC1) 1 1N4004 diode (D1) 1 5mm LED (LED1) 1 78L05 voltage regulator (REG1) Capacitors 2 0.1µF monolithic Resistors (0.25W, 1%) 2 10kΩ 1 560Ω 68 Silicon Chip All outputs to the port can be monitored via connector CON1, while a 4MHz ceramic resonator (CR1) provides the clock signals. The unit can be powered by an DC supply from 8-15V (eg, a plugpack). Diode D1 provides reverse polarity protection, while regulator REG1 provides a stable +5V rail to power IC1 and the UHF receiver module. Construction & testing With only a handful of components, the construction is not challenging. Fig.3 shows where all the parts go. Install the smallest components first and watch the orientation of everything except the resistors. Don’t forget the wire link and be sure to use a socket for IC1. Note that the UHF receiver module is installed with its red coil facing towards IC1 – see photo. The antenna consists simply of a 165mm length of insulated hookup wire. If you are using the receiver to control a board (eg, a relay board) that doesn’t have its own power supply, you will need to organise power to both. The DB25 connector is tied to ground, so you will probably only need to connect a positive lead from one board to the other. If you have any doubts about how it all goes together, you can leave out the PIC and the UHF receiver module until the power supply is sorted out. That way, they cannot be damaged if you make a mistake. In fact, it’s a good idea to check that there is +5V on pin 14 of IC1’s socket before switching off the power and installing the microcontroller and the receiver module. Testing simply involves sending data to the receiver and checking that the LED blinks. You can then check which pins have been set (ie, taken high) by using a multimeter to measure the voltages on CON1. Practical applications The accompanying photo shows the receiver connected to an 8-channel relay board, as sold by Oatley Electronics (see SILICON CHIP, September 2000). Basically, you can use any board which only requires eight data inputs (D0-D7) and requires no control lines. With six standard and two heavy duty relays, driving just about any load is no problem and password activation means you can selectively drive up to 256 separate relay boards. This view shows the transmitter board plugged into its companion RS232 interface board (see SC, Nov. 2003). siliconchip.com.au The UHF Wireless Parallel Port is ideal for controlling this 8-Channel Relay Board, as sold by Oatley Electronics. You can control any board which only requires eight data inputs (D0-D7) and requires no control lines. That’s a lot of relays! I’ve been using these boards in the garden to control irrigation solenoids and currently the back and front yards have one each, controlled by their own password. I had what is essentially a PIC-based alarm clock left over from another project and I simply set the start and stop times during the day for each relay. For example, in pseudo code: At 10:35 am: Send *1 ;Turn on relay 1 on card with the password “*” At 11:20 am: Send *0 ;Turn off all relays on card with the password “*” I imagine that this would be a very simple program for the PC, perhaps with a scheduling grid to show what SC is on and off at what time. siliconchip.com.au Where To Get The Parts Kits plus individual parts for this project are available from the author. Prices are as follows (kit prices include the PC board plus on-board parts only): (1). Wireless Parallel Port Receiver ................................................... $46.00 (2). Matching Transmitter Kit ............................................................. $28.00 (3). Transmitter/Receiver Kit Package Deal ....................................... $69.00 (4). RS232 Interface Kit For Transmitter ............................................ $25.00 (5). Programmed Microcontroller With Resonator ...... Rx $18.00; Tx $15.00 (6). Rubber Duck Antenna (see November 2003 article) ......... $19.00 each All prices include postage within Australia and GST. To order, write or email the author as follows: Nenad Stojadinovic, PO Box 320, Woden, ACT 2606. email: vladimir<at>u030.aone.net.au The Laipac UHF transmitter and receiver modules are also available from Commlinx Solutions at www.commlinx.com.au May 2004 69 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.altronics.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: www.altronics.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: www.altronics.com.au/ Vintage Radio By RODNEY CHAMPNESS, VK3UG Cataloging & disposing of your vintage radio collection Keeping records and other information is an important part of vintage radio collecting. It’s also important to sort and store spare parts in an orderly manner, otherwise you’ll never be able to find anything when you want it! From time to time, individual collectors and groups (such as the Historical Radio Society of Australia and the New Zealand Vintage Radio Society) organise special functions for displaying vintage radio collections and other artefacts associated with vintage radio. This equipment now forms a valuable part of our radio history, the more so when additional information from the era is included. Literature and signs and any other artefacts pertaining to the hobby all help to enhance any collection in an historical sense. Why keep records? Keeping records and other informa- Plastic bags can be used to protect vintage radio sets when they are not in use or on display. Be sure to store them in a cool dry place, away from direct sunlight. siliconchip.com.au tion about our vintage collections is an important part of the hobby. However, some collectors find that their interests change after a number of years and may therefore wish to dispose of their collection. Another likely scenario is that the collector may wish to move to a retirement village and may no longer have the necessary space to store vintage radios. Obviously, all the hard work involved in putting a vintage radio collection together will come to nothing if it is just carted to the local rubbish tip when you can no longer accommodate it. And that would be a great shame. An article in the NZVRS Bulletin for February 2002 by George Newlands titled “Some Ideas and Advice On The Disposal of a Collection” got me thinking about what will happen to my collection when I eventually move to a retirement village (or die). What would my kids do when I can no longer take an interest in my collection? They certainly don’t share my interest in vintage radio and I would hate to think that my collection would be taken to the tip because it is “just so much old junk”! Recently, I saw the collection amassed by a (now deceased) hobbyist in South Australia and was asked to give an indication as to its value. Unfortunately, his wife had no idea where to turn for assistance in disposing of the collection. Her husband had died some time back and in the meantime, some so-called “helpers” had helped themselves to quite a few pieces of equipment, which left a nasty taste in the lady’s mouth. Going from what is left, there must have been some quite valuable pieces in the collection which are now gone. May 2004 73 A spreadsheet program is ideal for keeping details of your vintage radio collection. Don’t have Excel? – try the spreadsheet that’s included in OpenOffice (it’s free). And in some cases, the prices paid were so low as to be considered an insult. She has been offered $3000 for what’s left, which fills a shed around 15 metres square. However, just five items that I recognise are worth almost $3000 – never mind the rest of the gear! That said, there are a couple of good reasons why the collection is worth much less than it should be. First, the collector had dismantled many sets in the course of his restoration work and they are still in bits. Second, he had no record of the items in his collection. With sets in bits, it would take weeks to find out which pieces belonged together. Even then, with such a large collection, it may not be possible to be sure what belonged with what. Identifying makes and models is not easy when they are in pieces and spread around the storage area. Unfortunately, the restorer had been struck down with a stroke in the middle of his work, hence the chaos. as a chore to be avoided. However, keeping accurate records doesn’t have to be a chore, as even quite simple systems can be quite effective. For example, one of the members of our local vintage radio club does keep very good records and these are a good example of just how useful they can be to the hobby. Every set in his collection is given a number and a label is attached to each set with that number. The number is then recorded in a book and on a file folder. The file folder includes all the information he has on the set and the work done to bring the set up to standard. He also knows where each set is located in his collection. Can I do this? Well, not really, although I do know where the important (to me) sets What do we do? Most of us who start out in this hobby are initially so enthusiastic that we rarely organise our collections properly. Instead, when we come across all those “beaut” vintage radios out there, we tend to grab them and hoard them but we generally have no idea which way our hobby is going. The result is a garage or room full of equipment that we’ve collected and stored in all sorts of odd places. To make matters worse, if you are like me, you tend to forget what you have and where you have put it. Keeping accurate records of what we have, where the items are and the spares that we have for restoration is usually not done – mainly because we think of it 74 Silicon Chip An old chest of drawers makes a handy storage cabinet for vintage radio parts. Self-adhesive labels make the parts easy to find. are located. I also know if they have been restored and I keep circuits and other information in various folders. However, I am like most other collectors, where record-keeping takes a back-seat compared to other activities of the hobby. On the other hand, the article by George Newlands and my recent experience of seeing a potentially wonderful collection in disarray has really got me thinking. Most collectors, including me, really need to look at cataloging their collections. We also need to better protect restored receivers and become more methodical in our methods of storing and accessing spare parts. This column has covered the restoration of many fine radios from the early 1900s to the 1970s. But once we’ve restored them, what do we do with them? Do we store them in the damp and dusty garage with junk in boxes put on top of them or do they have pride of place in the lounge room as they did many years ago? It really is a shame if we leave the elements to once again wreak havoc on a set that required so much effort to restore to working order. Cataloging your equipment Keeping a record of the equipment you have can be done in a couple of ways and need not be arduous. I simply use a large exercise book, suitably ruled up to keep track of my equipment and what has been done to it. Alternatively, computer-literate restorers could use a spreadsheet program to record equipment information and, in fact, I’ve recently started transferring some of my own records to a computerbased system. What sort of data should be in such a catalog? The information can be as simple or as complex as will satisfy your own needs. Here are a few column headings that you could use. (1). Set Number: this is needed so that individual sets can be easily identified. This number can be attached to the set with a removable label in an inconspicuous location. (2). Date Acquired: this is often handy to know. (3). Make: this helps identify and catalog brand names. (4). Model Number: so that you can quickly check what you already have. (5). Year of Manufacture: so that you siliconchip.com.au 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 Multi-drawer parts cabinets (available from electronics retailers) are ideal for storing smaller components. can quickly check a set’s age. (6). Restored – Yes/No: let’s you check whether or not the set has been restored to working order. (7). Date Restored: so that you know how long ago the set was restored. If the set hasn’t been given a run for some time, it should be “fired up” to make sure nothing has deteriorated since restoration. (8) Condition When Acquired: this is purely so that you can look back and remember how much work was put into the restoration task. (9). Brief Details On The Set: this information can include whether it is dual-wave, 4-valve or 5-valve, battery or AC operated, etc. (10). Cabinet: wooden, Bakelite, plastic or other. (11). Cabinet Type: console, table, mantel, portable, other. (12). Work Done on Set: briefly indicates the work that was necessary to restore the set to working order. (13). Where Located: in the garage, in the lounge room, etc, or loaned out to someone. (14). Approximate Unit Value: this can be filled in when the prices of sets at auction and elsewhere become known. (15). General: a column to record other bits and pieces of information about the set. Reference can also be made to suitable spares that may be stored in your workshop (wrecked chassis are a good source of parts). Of course, you may need more or siliconchip.com.au less columns than this but that’s up to you. Cataloging other items Having cataloged your complete equipment, it is also desirable to have a catalog of wrecked chassis, new and used components, and any literature and circuits that you have. Although I don’t have a catalog as such for my new components, I do have them sorted in a logical manner. For example, capacitors are sorted into values and voltages, and the physically smaller ones stored in small, re-sealable plastic bags (available from supermarkets, etc). A black marker pen is used to record the capacitor 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 KALEX • High Speed PCB Drills • PCB Guillotine Laser Labels • PCB Material – Negative or Positive Acting • Light Boxes – Single or Double Sided; Large or Small • Etching Tanks – Bubble • Electronic Components and Equipment for TAFEs, Colleges and Schools • Prompt Delivery We now stock Hawera Carbide Tool Bits A ring-back binder is used to keep the author’s vintage radio catalog neat and tidy. It lists all the sets in the my collection and their location, along with other relevant details. 718 High Street Rd, Glen Waverley 3150 Ph (03) 9802 0788 FAX (03) 9802 0700 Website: www.users.bigpond.net.au/kalex Email: kalexpcb<at>bigpond.net.au ALL MAJOR CREDIT CARDS ACCEPTED May 2004 75 Photo Gallery: 1934 Eclipse Radio “Endeavour Midget” This collection has proven to be very useful, as restoration is much easier if you have the relevant information (particularly circuits). Additionally, these sources are invaluable for crosschecking the accuracy of the information in my vintage radio articles. The storage of books and other printed matter is an art in itself and large libraries go to quite a bit of trouble to preserve their collections. Many will have noticed that some editions of their Australian Official Radio Service Manuals have paper that has discoloured and is very easy to tear. I understand that this is due to the type of paper used, which had quite a high acid content. I’m no expert on how to look after printed material but I usually store valuable books in re-sealable plastic bags. If you’re really keen, any really useful information can be scanned into a computer and stored on a disc to give fast access. Protecting vintage radios Manufactured by Eclipse Radio, Melbourne, in 1934, the Endeavour Midget was housed in a small, ornate wooden cabinet. It employed a 5-valve superhet circuit and tuned the medium-wave band. Its valve line-up was as follows: 77 (autodyne mixer), 6D6 (IF amplifier), 77 (anode bend detector), 89 (audio output stage) and a 280 (rectifier). Photo: Historical Radio Society of Australia, Inc. values on the outside of each bag and the bags are all then placed in order in a suitably marked box. It may sound like a lot of bother but it isn’t really – not when compared to searching for a particular value among hundreds (or thousands) of other parts. Similarly, my resistors are all sorted into values and wattage ratings and are housed in a number of multidrawer parts cabinets. These cabinets are readily available from electronics stores, some of which advertise in SILICON CHIP. I also keep a list of all the valves I have and whenever I acquire or use some, I note this down on my valve list. As a result, I can quickly check which valves types are in my collection and I also know how many of each particular type I have. Once again, all the valves of a particular type are placed in a plastic resealable bag which is marked on the outside with a marker pen. A lot of my valves are “pre-loved” and so I can’t 76 Silicon Chip identify them by their boxes – because they don’t have any. Those items that aren’t really suitable for cataloging can be stored in boxes that are suitably labelled with the contents. If you can obtain a number of boxes of the same size, it can make storage much easier as they can be easily stacked. In fact, I have been able to obtain a number of boxes that contained six reams of A4 paper, so I have a relatively uniform storage system. I also have some of my shelves labelled to indicate what items are stored on them. If possible, try to keep your vintage radio parts in one area, as it makes finding things just that bit easier. And be methodical with your records as you will not be able to remember where everything is located. Books & circuit diagrams I’ve always been a bit of a magpie and so I have accumulated many radio/ electronics books, magazines, circuits and other literature over the years. The first thing to be aware of here is that ultraviolet radiation from the Sun can be quite harmful to the cabinet and general finish of vintage radios. After all, when the sets were made, it was not anticipated that they would still be around 50-80 years later. Keeping vintage radios out of direct sunlight and in a dry room will greatly increase the longevity of the cabinet finish and the internal works. An example of the damage ultraviolet rays can do can be seen in the way that the red paint on many signs fades over time. Remember too how the clear 300-ohm ribbon feeder used on TV antenna systems many years ago would disintegrate within about a year when exposed to the Sun. So keep your vintage radios out of the Sun. Dust and household airborne chemicals can be harmful too. I remember years ago having to service a TV set in a household of heavy smokers. The whole of the set was covered in a brown sticky goo, including the chassis components, the cabinet and the screen. In that set, simply cleaning the screen made quite a difference to the brightness of the picture! In addition, the tuner contacts needed cleaning, along with many other things. Of course, I’m not suggesting that your vintage sets will suffer like this TV did. However, they will suffer to some extent if there are smokers in the siliconchip.com.au These cardboard boxes once held reams of paper but are now used to store the author’s valve collection. Each box is clearly labelled to show contents. house (as will the smokers). One thing is certain: the lounge room will be a cleaner environment than the kitchen, with its cooking fumes. If a receiver is going to be used in the kitchen, a build up of muck can be expected over a period of time and this will need to be cleaned off occasionally. If the radio is only used rarely in the home, it can be protected using plastic sheeting or, in the case of console sets, using a blanket. Ideally, though, sets should be stored in glass display cases to exclude dust but this is hardly practical in 99% of cases. Disposing of your collection Several members of our local club have disposed of either part or all of their collections in recent years. In fact, one member decided to auction his entire collection after losing interest in the hobby. Before doing so, he advertised his collection widely and, when auction day rolled around, there were buyers from interstate. Another decided to auction his col- lection as he was terminally ill and didn’t want to leave the task of disposing of his collection to his wife. He hadn’t kept a listing of his collection and several people were involved in cataloging it as best they could. This wasn’t complete by auction day but it was still a successful auction, despite a few items being left unsold. A third member decided to rationalise his collection and he arranged for it to be auctioned at a local hall. Fortunately, he kept very meticulous records which made it relatively easy to compile an accurate catalog. His collection was also extensively advertised and again there were buyers from interstate at the auction. Another way of disposing of individual items is to see if any of your relatives or friends would like to have them. Local museums may also be interested in individual items from your collection, so keep them in mind. In summary, well kept records will make your collection much more enjoyable, both for you and anyone visiting who may be interested in vintage radio. Additionally, it is wise to have your collection cataloged for insurance purposes. You may even need proper valuations to fully insure any really valuable items. Finally, regardless of the circumstances, when it comes to disposing of your vintage radios, try to make sure that they are passed on to those who appreciate their historical value. SC Limited Stock Electronics TestBench Electronics TestBench is a valuable 128-page collection of 20 top test equipment projects from the pages of SILICON CHIP. Includes: Power Supplies, Semiconductor Testers, Inductance Meter, Cable & Wiring Tester, Pink Noise Source, Zener Diode Tester, Crystal Checker, Sound Level Meter, Insulation Tester, Logic Probes, Low Ohms Tester, Remote Control Tester, Telephone Exchange Simulator, High-Voltage Insulation Tester. SPECIAL PRICE: $9 (INC P&P & GST). Note: may be shop-soiled. 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. siliconchip.com.au May 2004 77 FLUID LENSES: bringing things into focus At this year’s CeBIT Exhibition in Hannover, Germany, Philips Research demonstrated FluidFocus: a unique variable-focus optical lens system that has no mechanical moving parts. S uited to a wide range of optical wall and one of its end caps are coated focal length of the lens. By increasing the applied electric imaging applications including with a hydrophobic (water-repellent) such things as digital cameras, coating that causes the aqueous solu- field, the surface of the initially convex camera phones, endoscopes, home tion to form itself into a hemispherical lens can be made completely flat (no security systems and optical storage mass at the opposite end of the tube, lens effect) or even concave. As a result it is possible to make drives, the FluidFocus system mim- where it acts as a spherically curved lenses that transition smoothly from ics the action of the human eye using lens. The shape of the lens is adjusted being convergent to divergent and a fluid lens that alters its focal length by applying an electric field across back again. by changing its shape. In the FluidFocus technology demThe new lens, which lends itself the hydrophobic coating such that it to high-volume manufacturing, over- becomes less hydrophobic – a process onstrator exhibited at CeBIT 2004, the comes the fixed-focus disadvantages called ‘electro-wetting’ that results fluid lens measured 3mm in diameter of many of today’s low-cost imaging from an electrically induced change by 2.2mm in length, making it easy in surface-tension. to incorporate into miniature optical systems. As a result of this change in surface pathways. The FluidFocus lens consists of The focal range provided by the two immiscible (non-mixing) fluids tension, the aqueous solution begins to of different refractive index (optical wet the sidewalls of the tube, altering demonstrator extends from 5cm to inproperties). One is an electrically con- the radius of curvature of the meniscus finity and it is extremely fast: switching between the two fluids and hence the over the full focal range is obtained in ducting aqueous solution and the other less than 10ms. an electrically nonControlled conducting oil, both by a DC voltcontained in a short age and presenttube with transparing a capacitive ent end caps. load, the lens The internal surfaces of the tube Shapes of a 6-mm diameter lens taken at different applied voltages. Photo: Philips consumes virtu78 Silicon Chip siliconchip.com.au At left: researchers show the miniature variable lens along with the camera that contains the lens. Photo: Philips ally zero power, which for battery powered portable applications gives it a real advantage. The durability of the lens is also very high, Philips having already tested the lens with over one million focusing operations without loss of optical performance. It also has the potential to be both shock resistant and capable of operating over a wide temperature range, suiting it to mobile applications. Big Brother may soon be watching you . . . in focus! SC siliconchip.com.au A) Schematic cross section of the FluidFocus lens principle. (B) When a voltage is applied, charges accumulate in the glass wall electrode and opposite charges collect near the solid/liquid interface in the conducting liquid. The resulting electrostatic force lowers the solid/liquid interfacial tension and with that the contact angle and hence the focal distance of the lens. Diagrams: Philips. May 2004 79 Poor Man’s Metal Locator By Thomas Scarborough This unique metal locator contains just five components – a low-cost IC, a variable capacitor, two search coils and a crystal earpiece. And believe it or not, despite the apparently simplicity it is capable of surprisingly good results. T HIS CIRCUIT represents a brand new genre of metal locator. Although it borrows from other kinds of locators/detectors, its basic principle of operation is new. And while this may seem to stretch one’s credulity, the performance matches that of a budget Induction Balance (IB) detector. Build it – and you will see! During testing, it detected an old English penny at 150mm (6”) in air. However, I would only put my neck on the block for 125mm (5”), since a number of factors influence sensitivity. It roughly matches the performance of the now sadly misnamed Matchless Metal Locator (SILICON CHIP, June 80 Silicon Chip 2002), while using just one-fifth of the components. This locator may therefore represent the writing on the wall for budget IB types and even puts paid to most of the advantages (the few remaining ones) of Beat Frequency Operation (BFO) detectors. Overview Instead of using a search and a reference oscillator (as in the BFO type), or transmit and receive coils (as in IB), this detector uses two transmitters (or search oscillators) with IB-style coil overlap. As will be seen from Fig.1 and our photographs, these are extremely simple in design. Each oscillator comprises just one-quarter of a common quad op amp IC plus the search coil! The frequencies of the two oscillators are then mixed (in similar fashion to a BFO) to produce an audible heterodyne. On the surface of it, this design would seem to represent little more than a twinned BFO metal locator. However, what makes it different above all else (and significantly increases its range) is that each coil modifies the frequency of the adjacent oscillator through inductive coupling. This introduces the “balance” that is present in an IB metal locator and boosts sensitivity well beyond that of a BFO. siliconchip.com.au Beyond this, all that is required is a means to control the mixer output frequency, so that the metal locator can be tuned. This could be accomplished in a number of ways but the method chosen here is a variable capacitor (a standard 100pF AM radio tuner) wired between the two oscillator outputs. Since the concept borrows from both BFO and IB, we shall give a nod to each of these by naming the principle “Beat Balance”. Characteristics The main characteristics of beat balance (BB) are as follows: • Depending on the way it is designed, a BB metal locator potentially offers the same sensitivity as IB. • It requires no receiver amplifier or level detector, thus vastly simplifying design and reducing cost. The present circuit uses just two main components, while matching the performance of a budget IB metal locator (which would probably have 10-20 parts). • Both search oscillators are identical, therefore BB offers high immunity to voltage and temperature variations. This obviates the need for compensation circuits, including voltage reg-ulation. • Each search coil has the opposite response to metal, thus BB has a high degree of immunity to ground mineralisation. At the same time, it offers good discrimination at the point where the two search coils overlap This view inside the box shows the WHOLE circuit (with the exception of the coils, of course, and the tuning capacitor hidden under the PC board). output (pin 1) is delayed during transfer to inverting input pin 2. An approx. 8V/µs slew rate further delays switching of IC1a, thus setting up a rapid oscillation. One end of the search coil is further wired to the non-inverting input (pin 3), which stabilises operation. While pin 3 could be left “floating”, this would be a less satisfactory arrangement. Since different ICs have different slew rates, as well as different input impedances, they are unlikely to work in this circuit. However, the TL074CN IC is widely available and there should be no sourcing problems. The search coil is a critical part of the oscillator and needs to be suitably designed to achieve oscillation and to obtain the required frequency. While this frequency needs to be high, it should not be so high that noise or instability are introduced. Both the characteristics of IC1 and the inductance of the coil influence oscillator frequency, which lies around 260kHz without a Faraday shield. The Faraday shield approximately doubles the inductance of the coil, thus roughly halving the frequency. IC1b is wired in exactly the same The circuit The design is based on the simplest of inverter oscillators. As far as I am aware, this two-component op amp oscillator also represents a first. Let us focus first on IC1a. Since an inductor resists rapid changes in voltage (called reactance), any change in the logic level at IC1a’s Fig.1: the complete circuit – it could hardly be any simpler, could it? siliconchip.com.au May 2004 81 Fig.2: construction of the oscillator section could hardly be simpler. Follow the diagram and photograph above and you can’t go wrong! way as IC1a, except that its search coil is connected in opposite phase. As the search head is swept over the ground, the presence of metal increases the inductance of L1 and then L2, or vice versa, thus bringing about a dip in the oscillator frequencies. A third op amp, IC1c, is used to mix the output of the oscillators, thus creating an audible difference frequency, or beat frequency. This leads us to the one distinctive feature of BB. Not only does the presence of metal alter the frequency of a search oscillator but as in the case of IB, it also influences the adjacent coil. In fact, both coils influence each other through mutual induction, thus greatly enhancing the sensitivity of the system. Beyond this, we only need to find a method of tuning the metal locator. This is achieved using variable capacitor VC1, which further couples the two inductors (the search coils), thus offering a means of controlling balance. Almost any variable capacitor should work in this position, although it should preferably have a smaller value; eg, 47pF to 100pF. A small value capacitor (eg 47pF) can be wired in series with VC1 to reduce a larger value. A crystal earpiece is used for sound output. While a piezo sounder may be used (without integral electronics), this is not likely to offer good volume. If the volume in the earpiece is too high, use a suitable series resistor to 82 Silicon Chip reduce it. An inductive sounder or earpiece is not recommended, because it could overload IC1c. Current consumption is around 15mA. Therefore an 8 x AA battery pack should last around 70 hours. Construction There’s so little on the PC board that it would be difficult to make a mistake. OK, so you could put the IC in back-to-front, likewise the search coils’ starts and ends could be inadvertently swapped. Apart from that, there’s precious little to worry about. Fit the 12 stakes to the PC board and solder them into place, then solder the two jumper wires as shown. Normally we would say use resistor lead offcuts for this – but there aren’t any! You’ll have to use some tinned copper wire instead. Now comes the challenge of popu- lating the PC board! Since this is a sensitive, high-frequency circuit, I would recommend that IC1 be soldered directly to the PC board (ie, not socketed). So long as you insert this component the right way round, there would appear to be little to go wrong! The TL074CN is a fairly “tough bird”– but be reasonably quick with the soldering iron. Wire up the variable capacitor VC1, the socket for the crystal earpiece and the battery and switch (carefully note the polarity of the battery leads – an error here could destroy the circuit). It’s usual to insert the on-off switch in the positive battery lead. Some battery holders have solder tags, others (such as the one we used) need a 9V battery snap to connect them. Again, watch the polarity! Now mount the on-off switch and the jack socket (for the crystal earpiece) Two overlapping coils are wound using 30SWG wire and fastened to a non-metallic base. Fig.8 microphone cable connects the coils to the oscillator. siliconchip.com.au on the case. I used long bolts to clamp VC1 underneath the PC board and found this an easy and effective way of fixing the variable capacitor to the case. I used a slice of non-conductive rubber to isolate VC1 from the back of the PC board. Winding the coils Next, wind the two search coils. They are 70 turns of 30SWG (0.315mm) enamelled copper wire on 120mm diameter formers. Faraday electrostatic shields are essential for circuit stability. These are connected to 0V and should use balanced (figure-8) screened microphone cable. Winding of the coils is not critical and a little give and take is permissible. However they should be as close as possible to identical. Wind the coils around the formers, temporarily holding them together by passing stubs of insulating tape under them and pressing them together over the top. Once you have wound the coils, bind them tightly with insulating tape around their entire circumference. Scrape the enamel off the ends of the coils’ enamelled copper wires to solder them to the microphone cables. Now add Faraday shields. Prepare some long, thin strips of aluminium or tin-foil. Twist a 100mm length of bare wire around each coil, over the insulating tape. This wire provides electrical contact with the foil and is soldered to the microphone cable screens. Beginning at the base of the bare wires, wind the foil around the circumference of the coils, so that no insulating tape is still visible under the foil – but the foil should not complete a full 360°. Leave a small gap (say 10mm) so that the foil does not meet after having done most of the round. Now again tightly bind the coils with insulating tape Parts List – Poor Man’s Metal Locator 1 PC board, code 04105041, 51 x 64mm 1 plastic case, 150 x 90 x 50mm 1 TL074CN quad op amp (IC1) 1 10-100pF variable (tuning) capacitor, with knob 1 crystal earpiece 1 3.5mm mono earphone socket 1 8 x AA battery holder and batteries 1 battery snap (if required by holder) 1 SPST power switch 55m (approx.) 30SWG enamelled copper wire 2 lengths twin shielded balanced microphone coax (fig.8), approx. 2m long hookup wire 2 20mm lengths tinned copper wire (for PC board links) 2 lengths of aluminium foil, approx. 20mm wide (for shield) 1 length PVC conduit to suit (handle) 4 20mm M3 screws and nuts Suitable cable ties Clear polyester resin around their entire circumference. Attach the coils to the circuit by means of the specified microphone cables, being careful to identify the beginning and end wires correctly as shown. If these are not correctly identified, there could be a 20% loss of sensitivity. The Faraday shields should be connected to the cable screens and to 0V on the PC board as shown. Hardware The “hardware” construction is just as simple as the rest of the design. The two search coils are fixed to a plate of Masonite or similar, with a single PVC electrical conduit shaft attached. The control box, containing all of the electronics apart from the coils, attaches to the shaft via a pair of cable ties. The top of the shaft is then held in the hand just above the control box, while its upper length rests against the back of one’s forearm. Use a stiff, non-metallic plate for the search head. Masonite is both stiff and easy to work with (I cut up an old Masonite clipboard for the purpose). Before the coils (or anything else) are attached to the base plate, their best operating position needs to be determined. Begin by placing the two coils on the search head plate, directly on top of one another (that is, “meshed”), with their beginning and end wires positioned as shown. Turn VC1 to its mid-position. Switch the detector on, then slowly move the coils apart. When the coils have all but been separated from one another, a tone will be heard in the crystal earpiece. Adjust the coil positions so that this is a fairly low tone – then drill holes and use cable ties (several for each coil) to fasten them in this position on the plate. Once the cable ties have been tightened, carefully bend the coils until a low tone is again heard in the crystal earpiece. To lower the tone, create a greater overlap of the two coils (ie, a larger segment in the middle), and vice versa. To construct a shaft, saw the end off a length of PVC piping at a 25° angle. Drill holes through the pipe close to its bottom end and holes through the centre of the search plate. Then bind the pipe to the search plate with cable ties. The pipe (or shaft) will later be fixed permanently to the search plate The lid is secured to the PVC pipe by means of a couple of cable ties. When these are pulled tight, they really grip well! Then the lid (which is effectively now the base) is screwed onto the box – and presto! siliconchip.com.au May 2004 83 The “works” box (left) is mounted near the top of the PVC tube. This view shows the front of the box, with the earpiece socket, tuning capacitor and on/off switch. We haven’t put a fancy label on this project – it would sort of ruin the effect, wouldn’t it? Besides, the label would be on the underside. At right is the coil end, showing how it mounts to the PVC tube. with clear polyester resin (see below). The two coils need to be set rigidly in position on the search head, so that they will not move even slightly when the metal locator is in use. I would recommend that they be potted in clear epoxy resin, which is available from most hardware stores, together with the necessary hardener or catalyst. A section of one coil should be left exposed where the two coils intersect, so as to enable final fine adjustment. This section of coil may be temporarily protected with Blu-Tac. Be sure to plug the holes beneath the search head before pouring the resin, since it is very runny and sticks faster than many glues! The detector’s PVC shaft is bound to the search head with the resin. I tied the control box to the shaft with cable ties and used a little allpurpose glue to assist. Cable ties were further used to bind the cables to the shaft. No hand grip was attached to the prototype but the shaft was kept long at the top, so as to rest against the back of my forearm as I gripped the shaft with my hand. Checking it out Once construction is complete and everything checked, switch on The Patent That Came Close – But No Cigar! US Patent 4,196,391 of 1980, by Harold J Weber, was a good piece of original thinking that makes fascinating reading. It came so close to Beat Balance – but no cigar! The patent describes a metal locator which uses two transmitters, as does ours, balanced by a variable capacitor. However, the patent seeks “least interaction between the inductors”, while ours is almost entirely dependent on such interaction. In the patent, a variable capacitor is used to balance the frequencies of the two transmitters. Ours, on the other hand, uses variable capacitor VC1 to obtain a beat frequency. The patent mixes the two transmitter frequencies with a third frequency from a Beat Oscillator. The purpose of this is to provide binaural location of metal objects, which is the “primary object” of the patent. Ours obtains an audible heterodyne by mixing the two transmitter frequencies directly, its primary object being to boost sensitivity. Harold J. Weber states in his patent that he is “surprised” to find “pronounced improvement” by alternating the signals in the ears – for which he employs a Gate Oscillator and a Gate Switch Driver. Why the expression of surprise? It is hardly scientific language. My hunch is that the pronounced improvement lay not in the ears but in the coils. He considered that he had merely invented another “beat frequency detector type”, thus missing a significant breakthrough by a whisker. 84 Silicon Chip and tune VC1 until a clear difference frequency or heterodyne is heard in the crystal earpiece. This should ideally be a low tone of just a few tens of Hertz. It will be found that sensitivity is dependent to some extent on tone and some experimentation will yield the best frequency. If necessary, further adjust the coils, moving them further apart if the circuit is silent, or closer together if the frequency is too high. Bring a metal item close to the coils. It will be found that one coil causes the tone in the crystal earpiece to rise, while the other causes it to fall, with the overlapping segment offering discrimination between ferrous and non-ferrous metals. The detector should pick up a large coin (eg, 50c) at up to 150mm in air (125mm is a sure bet), while large metal objects (eg, a cake tin) will be detected at half a metre. At close range, it is capable of picking up a pin. When in use, hold the search head close to the ground, sweeping it to and fro. Unlike IB, the two coils give opposite responses to metal, which one soon becomes accustomed to. While the detector is unusually stable, readjustment by means of VC1 will inevitably be required, particularly immediately after switch-on. That said, I found this to be a very “well-behaved” metal locator. It was easy to build, easy to set up and is a SC joy to use. siliconchip.com.au 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 Power supply for hot wire cutter I would like details for making a power supply for cutting polystyrene, for foam core wings and floats for model float-planes, etc. At present I use a 240VAC to 50V transformer, with a slightly modified light dimmer on the secondary side, which works OK but is not particularly stable. I would like to try using an AT-type computer power supply as the power source. Output voltage would need to be about 26V at a current of about 3A to 5A, with either the voltage or current being adjustable to regulate the temperature of the cutting wire. Could you make some recommendations for the way in which this could be achieved? Would it require a different winding on the transformer and/ or could the output be taken between the +12V and -12V terminals? Output filtering would not be critical. (T. T., Tamworth, NSW). • Have a look at the Hot Wire Cutter we described in the April 2000 issue. We show you how to use the 12V or 5V outputs of a computer power supply with different types of resistance wire. Does PIC Programmer do high-end PICs? I have just successfully built the Portable PIC Programmer kit published in the September 2003 issue. I note that nowhere in the article is it explicitly stated which PIC parts are supported by this hardware and which are not. I am interested in using the InCircuit Serial Programming feature with a variety of PIC models. Can the PIC 18FXXX parts be programmed with this unit? If not, what modifications would be necessary? Does the high 13V programming voltage pose a problem for some chips? Any advice on this would be appreciated. (N. R., Gosford, NSW). • In the “Main Features” box on page 29 of the article, we mentioned that the programmer handles: (1) PIC16F84/A, 16F627/A, 16F628/A, 12F629 and 12F675 micros; and (2) PIC16F87X Power Transformer For Stereo Amplifier I have some questions about your SC480 amplifier module. I am thinking of making a stereo amplifier with two modules. However, I have not been able to find a transformer with the right voltage and current (Jaycar recommend their MM-1095 56V CT 134VA transformer). The problem is that the MM-1095 does not have enough power output to drive the two amplifiers in their worst-case load at once. I could use two of them but there are space and cost considerations. All of the more heavily-rated transformers that could be suitable have 25V secondaries. What sort of transformer would you recommend to supply power to both at the same time? Would a siliconchip.com.au 160VA 25V toroid (Jaycar Cat. MT2114) be suitable? Does the fact that the output would be 25V (vs 28V) matter? (B. M., Wellington, NZ). • While the specified Jaycar transformer is a little light on for a stereo power amplifier driving 8-ohm loads, it is not that far off and would be perfectly adequate if it is just to power a domestic stereo system playing normal program material. On the other hand, if you want to use it with 4-ohm loads and intend using it with a musical instrument, the power rating should be up around 300VA and the voltage should be 28V a side, as specified. Reducing it to 25V a side will reduce the ultimate power output by about 20%. & 24CXX EEPROMs with user-wired adapters. However, IC-Prog does support a number of PIC18F parts (check the drop-down list on the main menu and the help file). In theory, you can program these using ICSP and a similar wiring scheme to that shown in Figs.11 & 12. The programmer is primarily intended as a low-cost beginner’s programmer, so use with the highend micros was deemed unnecessary. As a result, we didn’t test any of the PIC18F parts with the programmer & software. In addition, the large memory sizes in these micros makes programming over an RS232 serial link rather slow. A better choice might be the USBconnected programmer, featured in the April 2003 edition. As far as we’re aware, high-voltage (13V) programming is supported by most devices for backward compatibility reasons. Check the programming specs for your particular device(s), available from www.microchip. com/1010/suppdoc/specs/index.htm Query on amplifier input earthing I recently built an ETI480 power amplifier as well as purchasing a spare SC480 (January & February 2003). This was as a consequence of the demise of my faithful ETI413 guitar amplifier which failed recently after many years of reliable use. The preamp module, complete with vibrato and reverb add-ons, was based on an ETI419 preamp and was intended to be used with the new power amplifiers. This preamp uses the 40V bipolar power supply divided to 15V. This is the same output arrangement as the SILICON CHIP 4-Channel Guitar Mixer from January 1992. I note the later model amplifiers, including the new Studio 350, have a 10Ω resistor which means that the input screen is above ground. If one of these is connected to a preamp usMay 2004 85 Converting A TV To An Oscilloscope Quick suggestion: maybe you could do a feature or article on converting a cheap or old television set into a crude oscilloscope – not a professional tool, by any means, but just an interesting exercise (educational?) in the workings of a TV, a permanent audio “visualiser” or something to entertain the kids. It can be done easily, especially as the power supply, etc are already present. In fact, here is a website for a home-built CRO: http://www.dansworkshop.com/ Homebuilt%20oscilloscope.shtml Thanks for the great magazine. Actually, I’m a kid but I would really like the article. (J. H., via email). ing the same power supply (common 0V), the signal is now applied between input and ground rather than across the input capacitor and resistor plus the 10Ω resistor. What are the issues (if any) of using the preamps described above? Are any modifications required? (P. E., via email). • If you only intend using a single 350W module in your proposed guitar amplifier, then the 10Ω resistor can be replaced with a link. The 10Ω resistor has only been included to improve separation between channels in a stereo setup. Crystal for 50MHz frequency counter I have recently purchased and constructed your “Low-Cost 50MHz Frequency Counter” from the October 2003 issue. It works but I can’t say “no worries”. On opening the kit of parts, I was somewhat surprised at the crystal that was supplied. It was a bulk supplied computer crystal not a Hy-Q unit as specified and it certainly does not work like a Hy-Q unit. It cannot be adjusted any closer than 340kHz above 4MHz and no amount of fiddling with extra capacitance will move it more than a few kilohertz. I rang the kitset supplier and queried the use of such a cheap and nasty crystal for a frequency counter – they may as well be lapped in a concrete mixer for the accuracy that they achieve. For 86 Silicon Chip • We have produced a number of projects which would interest you. First, to convert a VGA monitor to an oscilloscope, have a look at a series of articles in the July, August & September 1996 issues. Second, have a look at the Sound Card Interface article in August 2002. Finally, if you want to convert a TV to an oscilloscope, you could look at the Large Screen TV Storage CRO Adaptor published in the February 1982 issue of Electronics Australia. We can supply the SILICON CHIP back issues for $8.80 each, including postage, or the EA article for the same cost. most computer applications it doesn’t matter but for a counter timebase the requirement is a bit better than that. Apart from this aberration, it is great but lacks one thing. It needs to have the low frequency hi-res range extended to about 300Hz to enable the checking of sub-audible tones as they all require the 0.1Hz to be able to be read to ensure that they are correct as some decoders are pretty fussy as to what they will decode. (D. B., via email). • We suspect that you have a problem with your particular frequency meter. It is either a faulty PIC or faulty software, or the MC10116 is oscillating. The standard crystal will give far better results than the 350kHz error above 4MHz you are obtaining. At most, a 50 ppm crystal (as supplied) would be 2.5kHz out at 50MHz and this would be before any calibration. After calibration to a known frequency, the meter should be better than 10 ppm (ie, within 500Hz at 50MHz). This has been verified using test equipment (using the low-spec crystal) up to 50MHz. We recommended a low drift crystal so that it would not alter with temperature, however, most kit suppliers are providing a low-cost crystal instead. Readers wanting a better crystal can obtain these from Farnell Electronics or Hy-Q Electronics. Speech processor for transceivers I’m attempting to find out about a “Speech Processor for Transceivers” project that was published in the September 1991 issue of “Electronics Australia”. Does it provide gain, compression and an “over” beep? I vaguely remember someone doing a project such as this. Can you provide copies of this article? I’m mainly interested in gain as I’ve changed to a noise-cancelling mike (DSE product) in the tractor cab and the output seems too low. (D. P., Auckland, NZ). • It does provide gain, compression and beep. We can supply a photocopy of the article for $10, including airmail to New Zealand. Hot glue as high-voltage insulation I’ve just finished building the Remote Touch Lamp Dimmer project from the January & February 2002 issues and would like to ask about the necessity for the suggested “neutral cure silicone sealant” to presumably insulate metal nuts on the PC board. I’m reluctant to purchase a fresh tube because I’ll probably not use it again for some time – if at all. However, I do have some Selleys “No More Gaps” product as well as a hot-glue gun. There’s no info as to the make-up of the Selleys product on the label, so I’m not sure if what I have will suffice for the job of insulating the indicated areas on the dimmer’s PC board. If “No More Gaps” isn’t good enough, will glue from a hot glue gun be OK? (T. R., via email). • Hot glue will be fine. Query on SC480 output transistors If the SC480 was intended as a replacement for the ETI480 50W model, why does it have two output transistors per rail? It is more like the 100W upgrade of the ETI480, as described by ETI magazine. And then why also are the fuses for the unit more like the value needed for the 100W module. The reason I ask is that I have two damaged ETI480 50W modules I want to replace and I am concerned that the power supply I have will not be adequate for 100W modules. (B. J., via email). • The SC480 was always intended as a 100W (nominal) module. If you only wanted to drive 8-ohm loads, you could undoubtedly get away with just siliconchip.com.au two output transistors (and reduce the quiescent current accordingly) but we have not done any tests along these lines. Having the four output transistors also results in lower harmonic distortion when driving 8-ohm loads. Regulated power supplies in series I was wondering if it is possible to connect two 0-15V 25A variable regulated power supplies in series to produce a 0-30V 25A variable regulated power supply? (P. J., via email). • If both power supplies have outputs that are isolated from mains earth, it is probably possible to connect them in series but they must be identical otherwise any current limit will be determined by the smaller supply. If they have earthed outputs and you connect them in series, you run the risk of burning them out. Battery monitor for can cooler I am planning on building a can cooler using a Peltier assembly from Oatley Electronics. I would like to add a Car Battery Monitor (December 2003), to keep an eye on the battery voltage so (hopefully) the cooler can be turned off before the battery voltage is too low to start the car. Would it be possible to connect a relay across LED7 (<11.5V) – eg, Jaycar Cat. KG-9142 – to turn off the cooler should the battery voltage fall below 11.5V? Also, will 11.5V be enough to start the car? (J. H., Ipswich, Qld). • The LED output of the PIC chip will not drive a relay. You will need an NPN transistor and some other components to drive a relay with contacts suited to the current drain of the Peltier device. 11.5V is about the right setting although it might be too low for some of the latest cars. For a more elegant approach to this circuit problem, have a look at the Battery Guardian in the May 2002 issue. Speed alarm for a bus I’m looking to install the Digital Speedometer/Speed Alert kit in a bus which is pretty much all 24V. I was wondering if this would work as it is or would I need to change either or both the 1W resistor or the zener siliconchip.com.au Different capacitors in RIAA preamps A neighbour wants me to build the RIAA version of the Universal Stereo Preamplifier (April 1994). I recalled the same PC board being used in the Studio Twin-Fifty Stereo Amplifier (April 1995) so I went through my library of SILICON CHIP and noted that the value of the bipolar capacitor in series with R4 is 47µF in the first case and 22µF in the latter. Also, the Universal Preamplifier has a 0.33µF MKT capacitor to output whereas the version in the Twin Fifty amplifier has a 10µF bipolar capacitor. The configuration in the March 2002 RIAA Preamplifier diode that are in the circuit before the 5V regulator. (B. W., via email). • You will need to change the 16V zener diode to a 33V 1W type. Also, the 5V regulator will run hot and will either need a larger heatsink or must be mounted externally on an aluminium sheet. is also subtly different, as is the preamplifier stage in the LP Doctor (January 2001). My neighbour will use the preamplifier between his turntable and the SoundBlaster card in his computer and I’m hoping that you can advise which circuit is the preferred one. (J. H., Falmouth, Tas). • The feedback capacitor can be 22µF or 47µF. We specified the larger value in the universal design because its also used in the other preamp configuration. Similarly, for your application, the output capacitor can be 0.33µF or 10µF. We used the larger value in the later designs because the following stages have some low bass losses. Regarding the Li’l Pulser Train Controller from the February 2001 issue, can I adapt this to operate a 9V Lego train instead of 12V trains? (P. H., via email). • Yes, you can run 9V trains. The speed control will need adjusting to limit the maximum average voltage supplied to the motor. You can do this by increasing the 12kΩ resistor in series with the VR1 speed pot. This can be achieved by trial and error, using a 20kΩ trimpot in its place and adjusting so that the output maximum to the motor is 9V or less (average as measured with a multimeter set to DC volts) when a train is running on the tracks. ule as well. I am planning to use the systems on an “odd fire” V6 such as that used in Peugeot, Volvo, Renault, etc. I will have to check it but I think the Volvo V6 distributor has a Hall Effect trigger. Will both of the systems mentioned previously operate with a signal that is being supplied at 90-150 degree intervals? You also mention that one should not use this ignition system with EFI. If the engine has an EFI-only computer then I can’t see why it should not all work together, provided that the tacho signal is clean. (T. S., via email). • If the car runs two coils, you may need two separate ignition systems. If it uses only one coil, then it can be operated from the Hall Effect sensor. The crankshaft angle differences will be catered for with the trigger signal from the car. The ignition can be run with EFI but we took the view that the original ignition system would be best. The High Energy Ignition was intended for replacing the old Kettering (points/ coil) system or cars with Hall or reluctor triggers that did not run full computerised EFI and ignition. Ignition for Volvo V6 Woofer Stopper won’t work on deaf dogs I am considering using the Universal High-Energy Ignition System published in Electronic Projects for Cars, Vol.2. I may also need to use the Programmable Ignition Timing mod- I have just successfully completed a Woofer Stopper Mk2 (February 1996). I now wish to increase the output. I have only one piezo tweeter (KSN 1005A) connected at present but the Controller for 9V Lego trains May 2004 87 2-way crossover problem I’ve run into a problem with my bookshelf speakers currently being built. They are 2-ways and the mid-woofer I am using is 8Ω, while the tweeter is 6Ω. The sensitivity of the woofer is 88dB and the tweeter sensitivity is 91dB. The crossover frequency is 3.5kHz. I will be running these off a Pioneer VSX-D409 receiver. I have asked many people on how to attenuate the tweeter and bring the sensitivity closer to the woofers. One person with the same speakers recommended to put a 2.2Ω 10W resistor before the tweeter but Jaycar says “No, if the tweeter is drawing effect on the dogs doesn’t seem to be enough. Should I be considering the KSN 1177A TD? Any advice would be greatly appreciated. (P. L., via email). • You can use several KSN1005A tweeters in parallel (ie, connect the red plus terminal of one tweeter to the red terminal on each of the other tweeters. Similarly connect the negative terminal on each tweeter together). You can use three or four units for more sound level. Note that if the dog does not respond to the noise at close range then it may not respond even if the noise is made louder with more tweeters. This is because some dogs are deaf to ultrasonic frequencies. Many old dogs are completely deaf. Voltage hysteresis in Battery Guardian I have constructed a Battery Guardian kit (May 2002). The main question is how can I decrease the hysteresis of the “reset” value? The reset value I would like to achieve is about 1.1V. The closest I can get at the moment is 1.6V. I have tried increasing the 2.2MΩ but this hasn’t given me the desired result. I realise it would be a “ratio” situation but I can’t figure out which resistors are involved. A friend has also constructed this kit and has suggested that an “input” diode on the positive leg would protect the circuitry against accidental wrong connection. (P. C., via email). • An input diode will affect the volt88 Silicon Chip 100W, the amplifier may blow”. Information on the Mid-Woofer is available at: http://www.advanceae.com.au/ car/prod395.htm Information on the tweeter is at: http://www.advanceae.com.au/ car/prod385.htm I need your help! (P. W., via email). • The series resistor is the correct approach but since there is a 3dB difference in sensitivity, the resistor should be close to 6Ω rather than 2.2Ω. However, since this changes the tweeter circuit impedance, it will also change the crossover frequency so you will also have to reduce the tweeter capacitor to bring it back to 3.5kHz (or whatever). connected to a PC when it’s powered up. The two relays energise for the same reason. So there shouldn’t be a problem with your programmer when it’s used in the normal way. Avoid the use of sports coils age measurement and this would need to be accounted for in the setting up. The hysteresis can be reduced by changing the 220kΩ resistor between pins 1 and 3 of IC2a to 470kΩ. This should reduce the voltage sensing hysteresis to around 1V. I have a Hall Effect or reluctor ignition system (standard on 1986 Nissan Bluebird). The local auto electrician does not want to sell me a sports coil because he thinks the electronics cannot handle it. Can you give me an opinion on this and how one might ensure the electronics can cope or maybe how to upgrade them? (G. K., Stratford, NZ). • Your auto electrician is correct. We also do not recommend sports coils for use with our High Energy Ignition system. The primary coil current is significantly higher than with standard coils and the output voltage higher. This leads to less reliability. Generally sports coils can only be used with ignition systems designed to use them or they can be used with points although points life will be short. Windows-based EPROM programmer query Mains tone interference to PA amplifier I have just recently complete the EPROM Programmer project (November & December 2002, February 2003). I find that when power is applied to it, REG3 and Q15 get fairly hot. By looking at the circuit diagram I can’t see how these components could possibly draw excessive current. The output of REG3 is 12.9V and the power LED is glowing. I have not inserted an EPROM chip nor have I attempted to connect the programmer to a computer. Both of the relays switch when power is applied. Could you please help me? (G. H., via email). • If you run the EPROM Programmer without connecting it to a PC, this tends to turn on both Q15 and Vpp pass transistor Q5 at the same time – something that normally doesn’t happen when the programmer is connected to a PC. As a result, Q15 can draw significant current from the Vpp supply and both it and REG3 will get quite warm. This isn’t a fault, just something that happens when the programmer isn’t I am having a problem with the control tones put on the mains by the electricity supply authority breaking into a PA amplifier. I think the frequency is 1050Hz. I understand that the problem can be cured by winding the supply flex through and around a toroid but I am not sure what size toroid or the number of turns. Can you help? (K. C., via email). • It is extremely doubtful whether any simple filtering on the mains input to your PA amplifier is going to solve the problem. The problem is more likely to be radiation from the mains wiring in the building directly into the mic input wiring. Balanced mics will certainly help, as well as routing the mic cables away from any mains wiring, cables or transformers. DIY car amplifier not economic I am looking for a circuit for my major project for Year 12. Does SILICON CHIP have an amplifier which can be used to decently run a 12-inch subsiliconchip.com.au woofer in a car? Also do you have any kits which can be hooked up to a sub equaliser? I know Jaycar has a kit but I don’t know if it can be hooked up to an amplifier kit in a car system. Any help would be appreciated. (J. D., Port Macquarie, NSW). • We have described a number of modules which could be used to drive a subwoofer, with the recent Studio 350 being a good example. However, to run this amplifier you would need a high power DC-DC inverter and by the time you built both, it would be much cheaper to buy a car subwoofer amplifier from Jaycar. As an alternative, you might like to consider building a project or two from our “Electronic Projects for Cars” handbook. 10-cell Nicad charger wanted Having joined the radio control fraternity over the last 12 months, it is apparent that batteries and battery chargers have improved dramatically. You can buy very small chargers that will handle Nicads, NiMH, SLA and Li-ion that run from a car battery. The added advantage seems to be that you can charge packs of greater voltage than the car battery can supply; eg 10 NiMH cells, at up to 3A. Have you published a design that can charge eight 1.2V cells from a car battery? With the growth of electric flight and the demands for charging batteries, a 12V-based project that can handle the newer battery packs would be greatly appreciated by many modellers out there. (A. B., via email). • We have published a 12V Nicad charger which will cater for up to 10 cells, in the October 1995 issue. It uses Notes & Errata 3-Way Active Crossover, January 2003: the equation for the crossover frequency shown in Fig.4 is incorrect. It shows the whole bottom line within the square root symbol whereas only the 2 should be within the square root. Simple DC Power Supply, March 2004: a track is missing on the PC board layout between the anode of D5, cathode of D6 and the output of REG1. The corrected PC board pattern is shown at right. This error was also present in the PSU.ZIP design files mentioned in the article. An updated version can be downloaded from www.siliconchip.com.au Current Clamp Adaptor For DMMs, September 2003: as presented, the clamp adaptor is not suitable for use a Philips TEA1100 chip. You should make sure you can obtain that chip before you purchase the other major parts. We can supply the October 1995 issue for $8.80 including postage. Battery backup for cordless phones Recently, a storm passed over the Riverina which blacked out the area for an hour or so. During this time, I was unable to use my only phone which derives its power from the mains. If a fire had started, I would have been unable to report it. Has SILICON CHIP ever printed an article on a low-power 230VAC inverter (say 5-10W and with sinusoidal with 240VAC mains when the wiring is uninsulated. To make it safe, both the metal clip and the toroid must have insulating coatings. waveform) which could be used as a “no break” power supply for essential services? If not, would you consider giving it a run? (D. V., via email). • We would not produce a low power sinusoidal DC-AC inverter, as we don’t think its sales would justify the work required. However, you might like to look at the project entitled “Backup Battery For Cordless Phones” which does address your problem, in the October 1999 issue. This was followed in the December 1999 issue (Circuit Notebook pages) with a version for AC-powered cordless phones. More simply, you might also want to have a conventional phone installed so that you can still dial out in these SC circumstances. 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. siliconchip.com.au May 2004 89 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* 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. 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. 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. 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 PRACTICAL RF HANDBOOK by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* A guide to RF design for engineers, technicians, students and enthusiasts. Covers key topics in RF: analog design principles, transmission lines, couplers, transformers, amplifiers, oscillators, modulation, transmitters and receivers, propagation and antennas. 279 pages in paperback. Alternative fuel expert Carl Vogel gives you a hands-on guide with the latest technical information and easy-to-follow instructions for building a two-wheeled electric vehicle – from a streamlined scooter to a full-sized motorcycle. 384 pages in soft cover. *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* 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. 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. 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. 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 PRACTICAL RF HANDBOOK by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* A guide to RF design for engineers, technicians, students and enthusiasts. Covers key topics in RF: analog design principles, transmission lines, couplers, transformers, amplifiers, oscillators, modulation, transmitters and receivers, propagation and antennas. 279 pages in paperback. Alternative fuel expert Carl Vogel gives you a hands-on guide with the latest technical information and easy-to-follow instructions for building a two-wheeled electric vehicle – from a streamlined scooter to a full-sized motorcycle. 384 pages in soft cover. *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 Silicon Chip Back Issues Voice Operated Relay; AM Radio For Weather Beacons; Dual Diversity Tuner For FM Mics, Pt.2; Electronic Engine Management, Pt.12. April 1989: Auxiliary Brake Light Flasher; What You Need to Know About Capacitors; 32-Band Graphic Equaliser, Pt.2. March 1992: TV Transmitter For VHF VCRs; Thermostatic Switch For Car Radiator Fans; Valve Substitution In Vintage Radios. November 1994: Dry Cell Battery Rejuvenator; Novel Alphanumeric Clock; 80-M DSB Amateur Transmitter; 2-Cell Nicad Discharger. May 1989: Build A Synthesised Tom-Tom; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference. April 1992: IR Remote Control For Model Railroads; Differential Input Buffer For CROs; Aligning Vintage Radio Receivers, Pt.1. July 1989: Exhaust Gas Monitor; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm; The NSW 86 Class Electrics. June 1992: Multi-Station Headset Intercom, Pt.1; Video Switcher For Camcorders & VCRs; IR Remote Control For Model Railroads, Pt.3; 15-Watt 12-240V Inverter; A Look At Hard Disk Drives. December 1994: Car Burglar Alarm; Three-Spot Low Distortion Sinewave Oscillator; Clifford – A Pesky Electronic Cricket; Remote Control System for Models, Pt.1; Index to Vol.7. September 1989: 2-Chip Portable AM Stereo Radio Pt.1; High Or Low Fluid Level Detector; Studio Series 20-Band Stereo Equaliser, Pt.2. October 1989: FM Radio Intercom For Motorbikes Pt.1; GaAsFet Preamplifier For Amateur TV; 2-Chip Portable AM Stereo Radio, Pt.2. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY & Morse); FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM Stereo Radio, Pt.3; Floppy Disk Drive Formats & Options. January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR; Active Antenna Kit; Designing UHF Transmitter Stages. February 1990: A 16-Channel Mixing Desk; Build A High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2. March 1990: Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16-Channel Mixing Desk, Pt.2; Using The UC3906 SLA Battery Charger IC. April 1990: Dual Tracking ±50V Power Supply; Voice-Operated Switch With Delayed Audio; 16-Channel Mixing Desk, Pt.3; Active CW Filter. June 1990: Multi-Sector Home Burglar Alarm; Build A Low-Noise Universal Stereo Preamplifier; Load Protector For Power Supplies. July 1990: Digital Sine/Square Generator, Pt.1 (0-500kHz); Burglar Alarm Keypad & Combination Lock; Build A Simple Electronic Die; A Low-Cost Dual Power Supply. August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Mains Appliances (9 Minutes); Horace The Electronic Cricket; Digital Sine/Square Generator, Pt.2. October 1994: How Dolby Surround Sound Works; Dual Rail Variable Power Supply; Talking Headlight Reminder; Electronic Ballast For Fluorescent Lights; Electronic Engine Management, Pt.13. October 1992: 2kW 24VDC - 240VAC Sinewave Inverter; Multi-Sector Home Burglar Alarm, Pt.2; Mini Amplifier For Personal Stereos; A Regulated Lead-Acid Battery Charger. February 1993: Three Projects For Model Railroads; Low Fuel Indicator For Cars; Audio Level/VU Meter (LED Readout); An Electronic Cockroach; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.5. March 1993: Solar Charger For 12V Batteries; Reaction Trainer; Audio Mixer for Camcorders; A 24-Hour Sidereal Clock For Astronomers. April 1993: Solar-Powered Electric Fence; Audio Power Meter; ThreeFunction Home Weather Station; 12VDC To 70VDC Converter; Digital Clock With Battery Back-Up. June 1993: AM Radio Trainer, Pt.1; Remote Control For The Woofer Stopper; Digital Voltmeter For Cars. May 1995: Guitar Headphone Amplifier; FM Radio Trainer, Pt.2; Transistor/Mosfet Tester For DMMs; A 16-Channel Decoder For Radio Remote Control; Introduction To Satellite TV. September 1993: Automatic Nicad Battery Charger/Discharger; Stereo Preamplifier With IR Remote Control, Pt.1; In-Circuit Transistor Tester; +5V to ±15V DC Converter; Remote-Controlled Cockroach. August 1995: Fuel Injector Monitor For Cars; Gain Controlled Microphone Preamp; How To Identify IDE Hard Disk Drive Parameters. October 1993: Courtesy Light Switch-Off Timer For Cars; Wireless Microphone For Musicians; Stereo Preamplifier With IR Remote Control, Pt.2; Electronic Engine Management, Pt.1. December 1993: Remote Controller For Garage Doors; LED Stroboscope; 25W Audio Amplifier Module; A 1-Chip Melody Generator; Engine Management, Pt.3; Index To Volume 6. November 1990: Connecting Two TV Sets To One VCR; Build An Egg Timer; Low-Cost Model Train Controller; 1.5V To 9V DC Converter; Introduction To Digital Electronics; A 6-Metre Amateur Transmitter. January 1994: 3A 40V Variable Power Supply; Solar Panel Switching Regulator; Printer Status Indicator; Mini Drill Speed Controller; Stepper Motor Controller; Active Filter Design; Engine Management, Pt.4. January 1991: Fast Charger For Nicad Batteries, Pt.1; Have Fun With The Fruit Machine (Simple Poker Machine); Two-Tone Alarm Module; The Dangers of Servicing Microwave Ovens. February 1994:90-Second Message Recorder; 12-240VAC 200W Inverter; 0.5W Audio Amplifier; 3A 40V Adjustable Power Supply; Engine Management, Pt.5; Airbags In Cars – How They Work. March 1991: Transistor Beta Tester Mk.2; A Synthesised AM Stereo Tuner, Pt.2; Multi-Purpose I/O Board For PC-Compatibles; Wideband RF Preamplifier For Amateur Radio & TV. March 1994: Intelligent IR Remote Controller; 50W (LM3876) Audio Amplifier Module; Level Crossing Detector For Model Railways; Voice Activated Switch For FM Microphones; Engine Management, Pt.6. May 1991: 13.5V 25A Power Supply For Transceivers; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1. April 1994: Sound & Lights For Model Railway Level Crossings; Dual Supply Voltage Regulator; Universal Stereo Preamplifier; Digital Water Tank Gauge; Engine Management, Pt.7. July 1991: Loudspeaker Protector For Stereo Amplifiers; 4-Channel Lighting Desk, Pt.2; How To Install Multiple TV Outlets, Pt.2; Tuning In To Satellite TV, Pt.2. May 1994: Fast Charger For Nicad Batteries; Induction Balance Metal Locator; Multi-Channel Infrared Remote Control; Dual Electronic Dice; Simple Servo Driver Circuits; Engine Management, Pt.8. September 1991: Digital Altimeter For Gliders & Ultralights; Ultrasonic Switch For Mains Appliances; The Basics Of A/D & D/A Conversion. June 1994: A Coolant Level Alarm For Your Car; 80-Metre AM/CW Transmitter For Amateurs; Converting Phono Inputs To Line Inputs; PC-Based Nicad Battery Monitor; Engine Management, Pt.9. ORDER FORM April 1995: FM Radio Trainer, Pt.1; Balanced Mic Preamp & Line Filter; 50W/Channel Stereo Amplifier, Pt.2; Wide Range Electrostatic Loudspeakers, Pt.3; 8-Channel Decoder For Radio Remote Control. July 1995: Electric Fence Controller; How To Run Two Trains On A Single Track (Incl. Lights & Sound); Setting Up A Satellite TV Ground Station; Build A Reliable Door Minder. October 1990: The Dangers of PCBs; Low-Cost Siren For Burglar Alarms; Dimming Controls For The Discolight; Surfsound Simulator; DC Offset For DMMs; NE602 Converter Circuits. December 1991: TV Transmitter For VCRs With UHF Modulators; IR Light Beam Relay; Colour TV Pattern Generator, Pt.2; Index To Vol.4. March 1995: 2 x 50W Stereo Amplifier, Pt.1; Subcarrier Decoder For FM Receivers; Wide Range Electrostatic Loudspeakers, Pt.2; IR Illuminator For CCD Cameras; Remote Control System For Models, Pt.3. August 1993: Low-Cost Colour Video Fader; 60-LED Brake Light Array; Microprocessor-Based Sidereal Clock; Satellites & Their Orbits. November 1993: High Efficiency Inverter For Fluorescent Tubes; Stereo Preamplifier With IR Remote Control, Pt.3; Siren Sound Generator; Engine Management, Pt.2; Experiments For Games Cards. November 1991: Build A Colour TV Pattern Generator, Pt.1; A Junkbox 2-Valve Receiver; Flashing Alarm Light For Cars; Digital Altimeter For Gliders, Pt.3; A Talking Voltmeter For Your PC, Pt.2. February 1995: 2 x 50W Stereo Amplifier Module; Digital Effects Unit For Musicians; 6-Channel Thermometer With LCD Readout; Wide Range Electrostatic Loudspeakers, Pt.1; Oil Change Timer For Cars; Remote Control System For Models, Pt.2. June 1995: Build A Satellite TV Receiver; Train Detector For Model Railways; 1W Audio Amplifier Trainer; Low-Cost Video Security System; Multi-Channel Radio Control Transmitter For Models, Pt.1. July 1993: Single Chip Message Recorder; Light Beam Relay Extender; AM Radio Trainer, Pt.2; Quiz Game Adjudicator; Antenna Tuners – Why They Are Useful. September 1990: 3-Digit Counter Module; Simple Shortwave Converter For The 2-Metre Band; Taking Care Of Nicad Battery Packs. October 1991: A Talking Voltmeter For Your PC, Pt.1; SteamSound Simulator For Model Railways Mk.II; Magnetic Field Strength Meter; Digital Altimeter For Gliders, Pt.2; Military Applications Of R/C Aircraft. January 1995: Sun Tracker For Solar Panels; Battery Saver For Torches; Dual Channel UHF Remote Control; Stereo Microphone Preamplifier. September 1995: Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.1; Keypad Combination Lock; The Vader Voice; Jacob’s Ladder Display. October 1995: 3-Way Loudspeaker System; Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.2; Fast Charger For Nicad Batteries. November 1995: Mixture Display For Fuel Injected Cars; CB Transverter For The 80M Amateur Band, Pt.1; PIR Movement Detector. December 1995: Engine Immobiliser; 5-Band Equaliser; CB Transverter For The 80M Amateur Band, Pt.2; Subwoofer Controller; Knock Sensing In Cars; Index To Volume 8. January 1996: Surround Sound Mixer & Decoder, Pt.1; Magnetic Card Reader; Automatic Sprinkler Controller; IR Remote Control For The Railpower Mk.2; Recharging Nicad Batteries For Long Life. April 1996: 125W Audio Amplifier Module; Knock Indicator For Leaded Petrol Engines; Multi-Channel Radio Control Transmitter; Pt.3. May 1996: High Voltage Insulation Tester; Knightrider LED Chaser; Simple Intercom Uses Optical Cable; Cathode Ray Oscilloscopes, Pt.3. June 1996: Stereo Simulator (uses delay chip); Rope Light Chaser; Low Ohms Tester For Your DMM; Automatic 10A Battery Charger. July 1996: VGA Digital Oscilloscope, Pt.1; Remote Control Extender For VCRs; 2A SLA Battery Charger; 3-Band Parametric Equaliser;. August 1996: Introduction to IGBTs; Electronic Starter For Fluorescent Lamps; VGA Oscilloscope, Pt.2; 350W Amplifier Module; Masthead Amplifier For TV & FM; Cathode Ray Oscilloscopes, Pt.4. September 1996: VGA Oscilloscope, Pt.3; IR Stereo Headphone Link, Pt.1; High Quality PA Loudspeaker; 3-Band HF Amateur Radio Receiver; Cathode Ray Oscilloscopes, Pt.5. July 1994: Build A 4-Bay Bow-Tie UHF TV Antenna; PreChamp 2-Transistor Preamplifier; Steam Train Whistle & Diesel Horn Simulator; 6V SLA Battery Charger; Electronic Engine Management, Pt.10. August 1994: High-Power Dimmer For Incandescent Lights; Dual Diversity Tuner For FM Microphones, Pt.1; Nicad Zapper (For Resurrecting Nicad Batteries); Electronic Engine Management, Pt.11. September 1994: Automatic Discharger For Nicad Batteries; MiniVox October 1996: Send Video Signals Over Twisted Pair Cable; 600W DC-DC Converter For Car Hifi Systems, Pt.1; IR Stereo Headphone Link, Pt.2; Multi-Channel Radio Control Transmitter, Pt.8. November 1996: 8-Channel Stereo Mixer, Pt.1; Low-Cost Fluorescent Light Inverter; Repairing Domestic Light Dimmers; 600W DC-DC Converter For Car Hifi Systems, Pt.2. Please send the following back issues:________________________________________ Enclosed is my cheque/money order for $______or please debit my:  Bankcard  Visa Card  Master Card Card No. Signature ___________________________ Card expiry date_____ /______ Name ______________________________ Phone No (___) ____________ PLEASE PRINT Street ______________________________________________________ Suburb/town _______________________________ Postcode ___________ 92 Silicon Chip 10% OF SUBSCR F TO IB OR IF Y ERS OU BUY 10 OR M ORE Note: prices include postage & packing Australia ............................... $A8.80 (incl. GST) Overseas (airmail) ..................................... $A10 Detach and mail to: Silicon Chip Publications, PO Box 139, Collaroy, NSW, Australia 2097. Or call (02) 9979 5644 & quote your credit card details or fax the details to (02) 9979 6503. Email: silchip<at>siliconchip.com.au siliconchip.com.au December 1996: Active Filter For CW Reception; Fast Clock For Railway Modellers; Laser Pistol & Electronic Target; Build A Sound Level Meter; 8-Channel Stereo Mixer, Pt.2; Index To Vol.9. September 1999: Autonomouse The Robot, Pt.1; Voice Direct Speech Recognition Module; Digital Electrolytic Capacitance Meter; XYZ Table With Stepper Motor Control, Pt.5; Peltier-Powered Can Cooler. May 2002: 32-LED Knightrider; The Battery Guardian (Cuts Power When the Battery Voltage Drops); Stereo Headphone Amplifier; Automatic Single-Channel Light Dimmer; Pt.2; Stepper Motor Controller. January 1997: How To Network Your PC; Control Panel For Multiple Smoke Alarms, Pt.1; Build A Pink Noise Source; Computer Controlled Dual Power Supply, Pt.1; Digi-Temp Monitors Eight Temperatures. October 1999: Build The Railpower Model Train Controller, Pt.1; Semiconductor Curve Tracer; Autonomouse The Robot, Pt.2; XYZ Table With Stepper Motor Control, Pt.6; Introducing Home Theatre. June 2002: Lock Out The Bad Guys with A Firewall; Remote Volume Control For Stereo Amplifiers; The “Matchless” Metal Locator; Compact 0-80A Automotive Ammeter; Constant High-Current Source. February 1997: PC-Controlled Moving Message Display; Computer Controlled Dual Power Supply, Pt.2; Alert-A-Phone Loud Sounding Telephone Alarm; Control Panel For Multiple Smoke Alarms, Pt.2. November 1999: Setting Up An Email Server; Speed Alarm For Cars, Pt.1; LED Christmas Tree; Intercom Station Expander; Foldback Loudspeaker System; Railpower Model Train Controller, Pt.2. July 2002: Telephone Headset Adaptor; Rolling Code 4-Channel UHF Remote Control; Remote Volume Control For The Ultra-LD Stereo Amplifier; Direct Conversion Receiver For Radio Amateurs, Pt.1. March 1997: Driving A Computer By Remote Control; Plastic Power PA Amplifier (175W); Signalling & Lighting For Model Railways; Build A Jumbo LED Clock; Cathode Ray Oscilloscopes, Pt.7. December 1999: Solar Panel Regulator; PC Powerhouse (gives +12V, +9V, +6V & +5V rails); Fortune Finder Metal Locator; Speed Alarm For Cars, Pt.2; Railpower Model Train Controller, Pt.3; Index To Vol.12. April 1997: Simple Timer With No ICs; Digital Voltmeter For Cars; Loudspeaker Protector For Stereo Amplifiers; Model Train Controller; A Look At Signal Tracing; Pt.1; Cathode Ray Oscilloscopes, Pt.8. January 2000: Spring Reverberation Module; An Audio-Video Test Generator; Picman Programmable Robot; Parallel Port Interface Card; Off-Hook Indicator For Telephones. August 2002: Digital Instrumentation Software For Your PC; Digital Storage Logic Probe; Digital Thermometer/Thermostat; Sound Card Interface For PC Test Instruments; Direct Conversion Receiver For Radio Amateurs, Pt.2; Spruce Up Your PC With XP-Style Icons. May 1997: Neon Tube Modulator For Light Systems; Traffic Lights For A Model Intersection; The Spacewriter – It Writes Messages In Thin Air; A Look At Signal Tracing; Pt.2; Cathode Ray Oscilloscopes, Pt.9. February 2000: Multi-Sector Sprinkler Controller; A Digital Voltmeter For Your Car; An Ultrasonic Parking Radar; Safety Switch Checker; Sine/Square Wave Oscillator. June 1997: PC-Controlled Thermometer/Thermostat; TV Pattern Generator, Pt.1; Audio/RF Signal Tracer; High-Current Speed Controller For 12V/24V Motors; Manual Control Circuit For Stepper Motors. March 2000: Resurrecting An Old Computer; Low Distortion 100W Amplifier Module, Pt.1; Electronic Wind Vane With 16-LED Display; Glowplug Driver For Powered Models; The OzTrip Car Computer, Pt.1. November 2002: SuperCharger For NiCd/NiMH Batteries, Pt.1; Windows-Based EPROM Programmer, Pt.1; 4-Digit Crystal-Controlled Timing Module; Using Linux To Share An Optus Cable Modem, Pt.1. July 1997: Infrared Remote Volume Control; A Flexible Interface Card For PCs; Points Controller For Model Railways; Colour TV Pattern Generator, Pt.2; An In-Line Mixer For Radio Control Receivers. May 2000: Ultra-LD Stereo Amplifier, Pt.2; LED Dice (With PIC Microcontroller); Low-Cost AT Keyboard Translator (Converts IBM Scan-Codes To ASCII); 50A Motor Speed Controller For Models. August 1997: The Bass Barrel Subwoofer; 500 Watt Audio Power Amplifier Module; A TENs Unit For Pain Relief; Addressable PC Card For Stepper Motor Control; Remote Controlled Gates For Your Home. June 2000: Automatic Rain Gauge; Parallel Port VHF FM Receiver; Switchmode Power Supply (1.23V to 40V) Pt.1; CD Compressor. December 2002: Receiving TV From Satellites; Pt.1; The Micromitter Stereo FM Transmitter; Windows-Based EPROM Programmer, Pt.2; SuperCharger For NiCd/NiMH Batteries; Pt.2; Simple VHF FM/AM Radio; Using Linux To Share An Optus Cable Modem, Pt.2. October 1997: 5-Digit Tachometer; Central Locking For Your Car; PCControlled 6-Channel Voltmeter; 500W Audio Power Amplifier, Pt.3. November 1997: Heavy Duty 10A 240VAC Motor Speed Controller; Easy-To-Use Cable & Wiring Tester; Build A Musical Doorbell; Replacing Foam Speaker Surrounds; Understanding Electric Lighting Pt.1. December 1997: Speed Alarm For Cars; 2-Axis Robot With Gripper; Stepper Motor Driver With Onboard Buffer; Power Supply For Stepper Motor Cards; Understanding Electric Lighting Pt.2; Index To Vol.10. January 1998: Build Your Own 4-Channel Lightshow, Pt.1 (runs off 12VDC or 12VAC); Command Control System For Model Railways, Pt.1; Pan Controller For CCD Cameras. February 1998: Multi-Purpose Fast Battery Charger, Pt.1; Telephone Exchange Simulator For Testing; Command Control System For Model Railways, Pt.2; Build Your Own 4-Channel Lightshow, Pt.2. April 1998: Automatic Garage Door Opener, Pt.1; 40V 8A Adjustable Power Supply, Pt.1; PC-Controlled 0-30kHz Sinewave Generator; Build A Laser Light Show; Understanding Electric Lighting; Pt.6. May 1998: Troubleshooting Your PC, Pt.1; 3-LED Logic Probe; Automatic Garage Door Opener, Pt.2; Command Control For Model Railways, Pt.4; 40V 8A Adjustable Power Supply, Pt.2. June 1998: Troubleshooting Your PC, Pt.2; Universal High Energy Ignition System; The Roadies’ Friend Cable Tester; Universal Stepper Motor Controller; Command Control For Model Railways, Pt.5. July 1998: Troubleshooting Your PC, Pt.3; 15W/Ch Class-A Audio Amplifier, Pt.1; Simple Charger For 6V & 12V SLA Batteries; Auto matic Semiconductor Analyser; Understanding Electric Lighting, Pt.8. August 1998: Troubleshooting Your PC, Pt.4; I/O Card With Data Logging; Beat Triggered Strobe; 15W/Ch Class-A Stereo Amplifier, Pt.2. September 1998: Troubleshooting Your PC, Pt.5; A Blocked Air-Filter Alarm; Waa-Waa Pedal For Guitars; Jacob’s Ladder; Gear Change Indicator For Cars; Capacity Indicator For Rechargeable Batteries. October 1998: AC Millivoltmeter, Pt.1; PC-Controlled Stress-O-Meter; Versatile Electronic Guitar Limiter; 12V Trickle Charger For Float Conditions; Adding An External Battery Pack To Your Flashgun. November 1998: The Christmas Star; A Turbo Timer For Cars; Build A Poker Machine, Pt.1; FM Transmitter For Musicians; Lab Quality AC Millivoltmeter, Pt.2; Improving AM Radio Reception, Pt.1. December 1998: Engine Immobiliser Mk.2; Thermocouple Adaptor For DMMs; Regulated 12V DC Plugpack; Build A Poker Machine, Pt.2; Improving AM Radio Reception, Pt.2; Mixer Module For F3B Gliders. January 1999: High-Voltage Megohm Tester; A Look At The BASIC Stamp; Bargraph Ammeter For Cars; Keypad Engine Immobiliser. March 1999: Getting Started With Linux; Pt.1; Build A Digital Anemometer; Simple DIY PIC Programmer; Easy-To-Build Audio Compressor; Low Distortion Audio Signal Generator, Pt.2. April 1999: Getting Started With Linux; Pt.2; High-Power Electric Fence Controller; Bass Cube Subwoofer; Programmable Thermostat/ Thermometer; Build An Infrared Sentry; Rev Limiter For Cars. May 1999: The Line Dancer Robot; An X-Y Table With Stepper Motor Control, Pt.1; Three Electric Fence Testers; Heart Of LEDs; Build A Carbon Monoxide Alarm; Getting Started With Linux; Pt.3. June 1999: FM Radio Tuner Card For PCs; X-Y Table With Stepper Motor Control, Pt.2; Programmable Ignition Timing Module For Cars, Pt.1; Hard Disk Drive Upgrades Without Reinstalling Software? July 2000: Moving Message Display; Compact Fluorescent Lamp Driver; Musicians’ Lead Tester; Switchmode Power Supply, Pt.2. August 2000: Theremin; Spinner (writes messages in “thin-air”); Proximity Switch; Structured Cabling For Computer Networks. September 2000: Swimming Pool Alarm; 8-Channel PC Relay Board; Fuel Mixture Display For Cars, Pt.1; Protoboards – The Easy Way Into Electronics, Pt.1; Cybug The Solar Fly. October 2000: Guitar Jammer; Breath Tester; Wand-Mounted Inspection Camera; Subwoofer For Cars; Fuel Mixture Display, Pt.2. October 2002: Speed Controller For Universal Motors; PC Parallel Port Wizard; Cable Tracer; AVR ISP Serial Programmer; 3D TV. January 2003: Receiving TV From Satellites, Pt 2; SC480 50W RMS Amplifier Module, Pt.1; Gear Indicator For Cars; Active 3-Way Crossover For Speakers; Using Linux To Share An Optus Cable Modem, Pt.3. February 2003: PortaPal Public Address System, Pt.1; 240V Mains Filter For HiFi Systems; SC480 50W RMS Amplifier Module, Pt.2; Windows-Based EPROM Programmer, Pt.3; Using Linux To Share An Optus Cable Modem, Pt.4; Fun With The PICAXE, Pt.1. March 2003: LED Lighting For Your Car; Peltier-Effect Tinnie Cooler; PortaPal Public Address System, Pt.2; 12V SLA Battery Float Charger; Little Dynamite Subwoofer; Fun With The PICAXE, Pt.2 (Shop Door Minder); SuperCharger Addendum; Emergency Beacons. November 2000: Santa & Rudolf Chrissie Display; 2-Channel Guitar Preamplifier, Pt.1; Message Bank & Missed Call Alert; Protoboards – The Easy Way Into Electronics, Pt.3. April 2003: Video-Audio Booster For Home Theatre Systems; Keypad Alarm; Telephone Dialler For Burglar Alarms; Three Do-It-Yourself PIC Programmer Kits; PICAXE, Pt.3 (Heartbeat Simulator); Electric Shutter Release For Cameras. December 2000: Home Networking For Shared Internet Access; White LED Torch; 2-Channel Guitar Preamplifier, Pt.2 (Digital Reverb); Driving An LCD From The Parallel Port; Index To Vol.13. May 2003: Widgybox Guitar Distortion Effects Unit; 10MHz Direct Digital Synthesis Generator; Big Blaster Subwoofer; Printer Port Simulator; PICAXE, Pt.4 (Motor Controller). January 2001: How To Transfer LPs & Tapes To CD; The LP Doctor – Clean Up Clicks & Pops, Pt.1; Arbitrary Waveform Generator; 2-Channel Guitar Preamplifier, Pt.3; PIC Programmer & TestBed. June 2003: PICAXE, Pt.5; PICAXE-Controlled Telephone Intercom; PICAXE-08 Port Expansion; Sunset Switch For Security & Garden Lighting; Digital Reaction Timer; Adjustable DC-DC Converter For Cars; Long-Range 4-Channel UHF Remote Control. February 2001: An Easy Way To Make PC Boards; L’il Pulser Train Controller; A MIDI Interface For PCs; Build The Bass Blazer; 2-Metre Groundplane Antenna; The LP Doctor – Clean Up Clicks & Pops, Pt.2. March 2001: Making Photo Resist PC Boards; Big-Digit 12/24 Hour Clock; Parallel Port PIC Programmer & Checkerboard; Protoboards – The Easy Way Into Electronics, Pt.5; A Simple MIDI Expansion Box. April 2001: A GPS Module For Your PC; Dr Video – An Easy-To-Build Video Stabiliser; Tremolo Unit For Musicians; Minimitter FM Stereo Transmitter; Intelligent Nicad Battery Charger. May 2001: 12V Mini Stereo Amplifier; Two White-LED Torches To Build; PowerPak – A Multi-Voltage Power Supply; Using Linux To Share An Internet Connection, Pt.1; Tweaking Windows With TweakUI. June 2001: Universal Battery Charger, Pt.1; Phonome – Call, Listen In & Switch Devices On & Off; Low-Cost Automatic Camera Switcher; Using Linux To Share An Internet Connection, Pt.2; A PC To Die For, Pt.1. July 2001: The HeartMate Heart Rate Monitor; Do Not Disturb Telephone Timer; Pic-Toc – A Simple Alarm Clock; Fast Universal Battery Charger, Pt.2; A PC To Die For, Pt.2; Backing Up Your Email. July 2003: Smart Card Reader & Programmer; Power-Up Auto Mains Switch; A “Smart” Slave Flash Trigger; Programmable Continuity Tester; PICAXE Pt.6 – Data Communications; Updating The PIC Programmer & Checkerboard; RFID Tags – How They Work. August 2003: PC Infrared Remote Receiver (Play DVDs & MP3s On Your PC Via Remote Control); Digital Instrument Display For Cars, Pt.1; Home-Brew Weatherproof 2.4GHz WiFi Antennas; PICAXE Pt.7; A Digital Timer For Less Than $20. September 2003: Robot Wars; Krypton Bike Light; PIC Programmer; Current Clamp Meter Adapter For DMMs; PICAXE Pt.8 – A Data Logger; Digital Instrument Display For Cars, Pt.2. October 2003: PC Board Design, Pt.1; JV80 Loudspeaker System; A Dirt Cheap, High-Current Power Supply; Low-Cost 50MHz Frequency Meter; Long-Range 16-Channel Remote Control System. November 2003: PC Board Design, Pt.2; 12AX7 Valve Audio Preamplifier; Our Best Ever LED Torch; Smart Radio Modem For Microcontrollers; PICAXE Pt.9; Programmable PIC-Powered Timer. August 2001: DI Box For Musicians; 200W Mosfet Amplifier Module; Headlight Reminder; 40MHz 6-Digit Frequency Counter Module; A PC To Die For, Pt.3; Using Linux To Share An Internet Connection, Pt.3. December 2003: How To Receive Weather Satellite Images; Self-Diagnostics Plug For Cars; PC Board Design, Pt.3; VHF Receiver For Weather Satellites; Linear Supply For Luxeon 1W Star LEDs; MiniCal 5V Meter Calibration Standard; PIC-Based Car Battery Monitor; PICAXE Pt.10. September 2001: Making MP3s; Build An MP3 Jukebox, Pt.1; PCControlled Mains Switch; Personal Noise Source For Tinnitus; Directional Microphone; Using Linux To Share An Internet Connection, Pt.4. January 2004: Studio 350W Power Amplifier Module, Pt.1; HighEfficiency Power Supply For 1W Star LEDs; Antenna & RF Preamp For Weather Satellites; Lapel Microphone Adaptor FOR PA Systems; PICAXE-18X 4-Channel Datalogger, Pt.1; 2.4GHZ Audio/Video Link. November 2001: Ultra-LD 100W/Channel Stereo Amplifier, Pt.1; Neon Tube Modulator For Cars; Audio/Video Distribution Amplifier; Build A Short Message Recorder Player; Useful Tips For Your PC. December 2001: IR Transceiver For PCs; 100W/Ch Stereo Amplifier, Pt.2; Pardy Lights Colour Display; PIC Fun – Learning About Micros. January 2002: Touch And/Or Remote-Controlled Light Dimmer, Pt.1; A Cheap ’n’Easy Motorbike Alarm; 100W /Channel Stereo Amplifier, Pt.3; Build A Raucous Alarm; FAQs On The MP3 Jukebox. February 2002: 10-Channel IR Remote Control Receiver; 2.4GHz HighPower Audio-Video Link; Assemble Your Own 2-Way Tower Speakers; Touch And/Or Remote-Controlled Light Dimmer, Pt.2; Booting A PC Without A Keyboard; 4-Way Event Timer. July 1999: Build A Dog Silencer; 10µH to 19.99mH Inductance Meter; Audio-Video Transmitter; Programmable Ignition Timing Module For Cars, Pt.2; XYZ Table With Stepper Motor Control, Pt.3. March 2002: Mighty Midget Audio Amplifier Module; The Itsy-Bitsy USB Lamp; 6-Channel IR Remote Volume Control, Pt.1; RIAA Pre-Amplifier For Magnetic Cartridges; 12/24V Intelligent Solar Power Battery Charger; Generate Audio Tones Using Your PC’s Soundcard. August 1999: Remote Modem Controller; Daytime Running Lights For Cars; Build A PC Monitor Checker; Switching Temperature Controller; XYZ Table With Stepper Motor Control, Pt.4; Electric Lighting, Pt.14. April 2002:Automatic Single-Channel Light Dimmer; Pt.1; Water Level Indicator; Multiple-Output Bench Power Supply; Versatile Multi-Mode Timer; 6-Channel IR Remote Volume Control, Pt.2. siliconchip.com.au September 2002: 12V Fluorescent Lamp Inverter; 8-Channel Infrared Remote Control; 50-Watt DC Electronic Load; Driving Light & Accessory Protector For Cars; Spyware – An Update. February 2004: Hands-On PC Board Design For Beginners, Pt.1; Simple Supply Rail Monitor For PCs; Studio 350W Power Amplifier Module, Pt.2; Using The Valve Preamp In A Hifi System; Fantastic Human-Powered LED Torches; Shorted Turns Tester For Line Output Transformers; PICAXE-18X 4-Channel Datalogger, Pt.2. March 2004: Hands-On PC Board Design For Beginners, Pt.2; Build The QuickBrake For Increased Driving Safety; 3V-9V (or more) DC-DC Converter; The ESR Meter Mk.2, Pt.1; Power Supply Demo Design; White LED Driver; PICAXE-18X 4-Channel Datalogger, Pt.3. April 2004: Hands-On PC Board Design For Beginners, Pt.3; Loudspeaker Level Meter For Home Theatre Systems; Shut That Mutt (Electronic Dog Silencer); Smart Mixture Display For Cars; The ESR Meter Mk.2, Pt.2; PC/PICAXE Interface For UHF Remote Control. PLEASE NOTE: issues not listed have sold out. All other issues are in stock. We can supply photostat copies from sold-out issues for $8.80 per article (includes p&p). When supplying photostat articles or back copies, we automatically supply any relevant notes & errata at no extra charge. A complete index to all articles published to date can be downloaded free from our web site: www.siliconchip.com.au May 2004 93 MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. CLASSIFIED ADVERTISING RATES Advertising rates for this page: Classified ads: $20.00 (incl. GST) for up to 20 words plus 66 cents for each additional word. Display ads: $33.00 (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  Bankcard  Visa Card  Master Card Card No. Signature__________________________ Card expiry date______/______ Name _____________________________________________________ Street _____________________________________________________ Suburb/town ___________________________ Postcode______________ Phone:_____________ Fax:_____________ Email:__________________ 94 Silicon Chip FOR SALE UNIVERSAL DEVICE PROGRAMMER: Low cost, high performance, 48-pin, works in DOS or Windows incl. NT/2000. $1100. Universal EPROM programmer $374.00. Also adaptors, (E)EPROM, PIC, 8051 programmers, EPROM simulator and eraser. Dunfield C Compilers: Everything you need to develop C and ASM software for 68HC08, 6809, 68HC11, 68HC12, 68HC16, 8051/52, 8080/85, 8086, 8096 or AVR: $198 each. Demo disk available. 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 PCBs MADE, ONE OR MANY. Any format, hobbyists welcome. Sesame Electronics (02) 9593 1025. sesame777<at>optusnet.com.au http://sesame_elec.tripod.com MAGGYLAMPS: We have a full range of magnifying lamps, ex-stock, Australianmade and imported. Ask for catalogue. Ph 1300 788 239. AUDIO COMPONENTS from Original Manufacturers: Toshiba, Sanken, Hitachi, Wima factory-direct. Guarantee cheapest prices across Australia. Call James, Praise! Audio 0422 125 998. Email: jyung<at>maths.uwa.edu.au S-Video . . . Video . . . Audio . . . VGA distribution amps, splitters, standards converters, tbc’s, switchers, cables, etc, & price list: www.questronix.com.au siliconchip.com.au Circuit Ideas Wanted Do you have a good circuit idea? If so, sketch it out, write a brief description of its operation & send it to us. Provided your idea is workable & original, we’ll publish it in Circuit Notebook & you’ll make some money. We pay up to $60 for a good circuit so send your idea to: Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. MEGABRIGHT LEDS! 5mm superbright whites, blues and greens, from 60 cents each. 5mm RGB LEDs $1.25 each. 4-chip (80mA) megabright LEDs from $1.25 each. Lithium batteries from 40 cents each. www.ledsales.com.au sPlan Windows electronic schematic software and Sprint Layout Windows PCB layout software are feature packed but low in price. Pixel Programmable Controller with 4 analog inputs, 8 digital inputs and 8 relay outputs. Can use a 28A or 28X Picaxe. Programmed in Basic or Flow chart. Labjack USB Data Acquisition Module features 8 12bit analog inputs, 20 digital I/O, 2 analog outputs and high speed counter. Free software, Labview driver and ActiveX component. DAS005 Parallel Port Data Acquisition Module features 8 12bit Analog inputs, 4 Digital I/Ps & 4 Digital O/Ps. Free windows software and source code. Dual Relay Modules suitable for TTL and Open Collector Outputs. Programmers for Atmel and PIC microcontrollers. Stepper Motor and Servo Motor controller kits. Switch Mode and Linear Power Supplies and DC-DC convertors. Full details and credit card ordering available at: www.oceancontrols.com.au KITS KITS AND MORE KITS! Check ’em out at www.ozitronics.com 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 by government departments, farmers, pilots and weather enthusiasts. Other models with barometric pressure, humidity, dew point, solar radiation, UV, siliconchip.com.au New New New 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) 9682 2487 Mark22-SM Slimline Mini FM R/C Receiver speakerbits.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°. 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 • • • • • 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 TAIG MACHINERY Micro Mini Lathes and Mills From $489.00 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 Silicon Chip Binders H Each binder holds up to 12 issues H SILICON CHIP logo printed in goldcoloured lettering on spine & cover Price: $A12.95 plus $A5 p&p each (Australia only; not available elsewhere). Buy five and get them postage free. REAL VALUE AT $12.95 PLUS P & P Just fill in & mail the handy order form in this issue; or fax (02) 9979 6503; or ring (02) 9979 5644 & quote your credit card number. 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. USB KITS: Stepper Motor Controller, USB PIO Interface, DTMF Transceiver, Thermometer, DDS HF Generator, Compass, 4-Channel Voltmeter, I/O Relay Card. Also available: Digital Oscilloscope, Temperature Loggers, VHF Receivers and USB Active X (and USBDOS.exe file) to control our kits from your application. www.ar.com.au/~softmark May 2004 95 Do You Eat, Breathe and Sleep Technology? Management & Sales Positions We are a rapidly growing, Australian-owned international retailer with more than 30 stores in Australia and we have a growing expansion program to open many more, so we need dedicated individuals to join our team to help achieve our goals. If you are customer focused, have an eye for detail, empathy for the products we sell and have recently completed a TAFE of University degree in electronics, we want to meet you. Career opportunities with full training are available now if you have the drive and ambition to make your future with Jaycar. We offer a competitive salary, sales commission and many other benefits. To apply for these positions please send your C.V. indicating the role you are interested in to the address shown below. Jaycar Electronics is an equal opportunity employer and actively promotes staff from within the organisation. Retail Operations Manager Jaycar Electronics Pty. Ltd. P.O. Box 6424 Silverwater NSW 1811 Fax: (02) 9741-8500 Email: jobs<at>jaycar.com.au Advertising Index Acetronics....................................94 Altronics................................. 70-72 Av-Comm.....................................95 Carba-Tec Tools...........................96 Dick Smith Electronics........... 14-17 Eco Watch....................................95 Elan Audio....................................41 Elexol...........................................43 Evatco..........................................75 Gadget Central...........................IFC Grantronics...................................94 Harbuch Electronics.....................55 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 and others. Tel (02) 9738 0330. sales<at>rcsradio.com.au, www.rcsradio.com.au Building speaker boxes? Mounting electrical components onto solid timber? You may need the Carba–tecTOOLS FOR WOOD catalogue!! We have Australia’s largest range of woodworking handtools & machinery. Please contact us for your FREE 220 page colour catalogue or come in & see us at: 113 STATION RD, AUBURN 2144 NEW ADDRESS! PH: 9648 6446; FAX 9648 6443; www.carbatec.com.au KIT ASSEMBLY Hy-Q International........................57 Instant PCBs................................96 Jaycar .......................... 45-52,57,96 JED Microprocessors................5,57 Kalex............................................75 Microgram Computers....................3 MicroZed Computers...............13,43 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 Newtek Sales...............................65 Oatley Electronics........................23 Ozitronics................................37,43 Prime Electronics.........................79 WANTED ntosh, Goodmans, Wharfedale, Tannoy, radio and wireless. Collector/Hobbyist will pay cash. (02) 9440 1267. johnmurt<at>highprofile.com.au EARLY HIFI’S, AMPLIFIERS, Speakers, Turntables, Valves, Books, Quad, Leak, Pye, Lowther, Ortofon, SME, Western Electric, Altec, Marantz, McI- HISTORIC RT&H “Transporta” 4, 6 or 7 portable kitset radios, comp. or incomp. Fair price paid. Laurie (03) 5968 4856 after 8pm. Quest Electronics....................57,95 RCS Radio...................................96 RF Probes....................................75 Silicon Chip Back Issues........ 92-93 Silicon Chip Binders................65,69 Silicon Chip Bookshop........... 90-91 SC Car Projects Book...........32,IBC Silicon Chip Subscriptions...........44 NOW AVAILABLE FROM SILICON CHIP www.siliconchip.com.au SC Electronics Testbench............77 Silvertone Electronics..................94 Soundlabs Group.........................57 Speakerbits..................................95 Taig Machinery.............................95 Telelink Communications.... OBC,57 WIA..............................................57 Project Reprints – Limited Back Issues –Limited One-Shots If you’re looking for a project from ELECTRONICS AUSTRALIA, you’ll find it at SILICON CHIP! We can now offer reprints of all projects which have appeared in Electronics Australia, EAT, Electronics Today, ETI or Radio, TV & Hobbies. First search the EA website indexes for the project you want and then call, fax or email us with the details and your credit card details. Reprint cost is $8.80 per article (ie, 2-part projects cost $17.60). SILICON CHIP subscribers receive a 10% discount. We also have limited numbers of EA back issues and special publications. Call for details! visit www.siliconchip.com.au or www.electronicsaustralia.com.au 96 Silicon Chip ____________________________ PC Boards Printed circuit boards for SILICON CHIP projects are made by: RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. siliconchip.com.au siliconchip.com.au May 2004 97