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SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au Contents Vol.20, No.2; February 2007 SILICON CHIP www.siliconchip.com.au Features 11 Viganella: Solar Power With A Twist Imagine living in a village with no sunlight for 84 days straight. The Italian village of Viganella solved the problem using a giant mirror – by Ross Tester 14 New “Naked” WiFi Distance Record Think WiFi is only good for 100 metres? Well the record for a non-amplified signal is now 280km! Here’s how they did it – by Ermanno Pietrosemoli 40 Review: Teac GF350 Turntable/CD Burner You’ll love this unit if you have lots of old vinyl records – by Barrie Smith Remote Volume Control & Preamp Module – Page 24. 42 Review: Jaycar Gets Into Wireless Microphones Jaycar enters the wireless microphone market with three attractively-priced models – by Ross Tester 57 Mater Maria College Scoops Technology Prize Pool Two students from Mater Maria Catholic College, Warriewood, win our inaugural “Excellence in Education Technology” awards Pro jects To Build 24 Remote Volume Control & Preamplifier Module; Pt.1 This digital unit works with any universal remote control and features an attractive blue LED readout and an optional rotary encoder – by Peter Smith 36 Simple Variable Boost Control For Turbo Cars Variable Boost Control & Fuel Cut Defeater – Pages 36 & 38. Simple circuit “intercepts” and stretches the standard boost control signal for even greater engine performance – by Denis Cobley 38 Fuel Cut Defeater For The Boost Control Use this with the Variable Boost Control to eliminate the standard factory fuel cut to the injectors at boost levels of 16-17psi – by Denis Cobley 58 Low-Cost 50MHz Frequency Meter; Mk.2 Review: Teac GF350 Turntable/CD Burner – Page 40. Updated project can run from internal batteries and now includes a 10kHz rounding mode for measuring 36MHz PPM R/C transmitters – by John Clarke 78 Bike Computer To Digital Ammeter Conversion Stan takes a cheap bike computer and turns it into a digital amp-hour meter with the aid of the mighty Picaxe! – by Stan Swan Special Columns 44 Serviceman’s Log Customers and their strange antics – by the TV Serviceman 70 Circuit Notebook (1) 4-Channel RF Remote Switch; (2) Sinewave-To-Digital Clock Shaper; (3) Tachometer & Elapsed Time Accumulator; (4) Picaxe-Controlled MP3 Doorbell 88 Vintage Radio The quirky Breville 801 personal portable – by Rodney Champness Departments   2   4 76 83 Publisher’s Letter Mailbag Product Showcase Order Form siliconchip.com.au 98 Ask Silicon Chip 101 Notes & Errata 102 Market Centre Low-Cost 50MHz Frequency Meter, Mk.2 – Page 58. February 2007  1 SILICON CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Editor Peter Smith Technical Staff John Clarke, B.E.(Elec.) Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Reader Services Ann Jenkinson Advertising Enquiries Glyn Smith Phone (02) 9939 3295 Mobile 0431 792 293 glyn<at>siliconchip.com.au Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Kevin Poulter 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: $89.50 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial office: Unit 1, 234 Harbord Rd, Brookvale, NSW 2100. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9939 3295. Fax (02) 9939 2648. E-mail: silicon<at>siliconchip.com.au ISSN 1030-2662 * Recommended and maximum price only. 2  Silicon Chip Publisher’s Letter Let’s not vacillate on nuclear power Just over a year ago, in the January 2006 issue, I wrote in the Publisher’s Letter that Australia should build nuclear power stations. Furthermore, I advocated that it be used to power the proposed desalination plant in Sydney. Well, the political climate has certainly changed since then! The New South Wales Government has back-tracked on the desalination plant, in the forlorn hope that it would rain enough to fill the dams. Didn’t happen, did it? But on a more positive note, the Federal Government commissioned a report from Ziggy Switkowski, on “Uranium Mining, Processing and Nuclear Energy”. This 294-page report has just been released and the omens are generally favourable to nuclear power. Having read the report, I can summarise it in the following way: Uranium mining is generally safe and worthwhile for Australia and we should produce more of it; Uranium processing is very expensive and we shouldn’t touch it with a barge pole and finally, Nuclear Power is safe but much more expensive than Australia’s existing coal-fired power stations. It will never be competitive with coal-fired power stations unless a substantial carbon tax is levied on them. There seems to be little doubt about the first part: we should export more uranium to other countries. The second part also seems indubitable – so don’t process in Australia. The third part is more questionable – should we bother with nuclear power if we have to artificially make coal power more expensive to make nuclear power viable? I suggest that is the wrong question. The Federal Government is unlikely to bring in a carbon tax on all coal-fired power stations just to make nuclear power stations viable and nor should it. Rather, if nuclear power stations are to be built, to reduce Australia’s greenhouse gas emissions, the Government should make a policy decision that nuclear power stations will be part of the national grid and will be able to sell their higher-cost electricity to it – just as higher-cost wind power already is. Consumers will pay more but they are likely to pay more in the future, whether we have nuclear power stations or not. Having said that, some of the assumptions in the Report seem questionable. For example, Australia’s electricity demand is estimated to double by 2050, even though energy consumption per unit of GDP is declining. Furthermore, as stated in the Report, “consumption is expected to grow at around 2 per cent per year to 2030. The bulk of the electricity will continue to used in industry and commerce but domestic consumption is also expected to increase”. In effect, the Report says that electricity consumption will continue to grow inexorably and there will be no real drive for businesses and households to reduce their power use. So will we continue to waste ever more power? I suggest that if water consumption in all Australian cities can be drastically curtailed by stringent restrictions but little in the way of economic sanctions (ie, price rises), then there must be enormous scope for reductions in electricity consumption over the next 40-odd years, with no reduction in economic output or living comfort. Think about it: the majority of households could undoubtedly be re-designed to provide just as much, if not more, living comfort while using substantially less energy. This has been done on a very large scale in Europe and the USA. And undoubtedly, most businesses could affect major savings in electricity consumption if they really had to, because of higher prices or restrictions. So by all means let’s build some nuclear power stations to provide base load power while reducing our overall greenhouse gas emissions. But let’s not just continue to use electricity wastefully. Surely, we are more clever than that. Leo Simpson siliconchip.com.au Performance on-the-move Strength in the palm of your hand Say hello to the next generation of Agilent Technologies; the new handheld digital multimeters and oscilloscopes From only $586 + GST ($645 inc. GST) NEW U1250A series handheld DMMs place versatility at your fingertips! that are built to test and designed to save. • 50,000 count resolution, dual displays and innovative new features and over-mould casing for • Unlimited data logging from DMM to PC protection in the toughest conditions. • Programmable square wave generator If you need a test instrument that offers the ultimate • Temperature, Capacitance, Maths functions portable test capabilities, Agilent’s range of handheld • 20MHz frequency counter NEW U1600A series handheld scopes bring high performance on the move! • Scope-DMM-Recorder - all-in-one • 4.5-inch LCD colour display • FFT, Zoom and Math functions • 200MSa/s sampling rate From only $2,006 + GST ($2,207 inc. GST) • 125kB/ch memory depth Distributed in Australia by Featuring built-in battery charging capability, exciting digital multimeters and oscilloscopes are the right choice. “At last, high performance handhelds designed specifically for Electronics Professionals, at a very affordable price.” • Hi-performance functions specifically for electronics • Free PC connectivity software (optional cables required) • Extremely rugged and robust construction • Calibration certificate included • 3-year Australian warranty Download product brochures, view online demos and purchase online at . . . www.measurement.net.au Measurement Innovation Pty Ltd Tel: 1300 726 550 VisaTM, MastercardTM and PayPalTM accepted www.measurement.net.au info<at>measurement.net.au Agilent Technologies MAILBAG Comments on suggested projects In your November 2006 editorial you asked whether people were in favour of the development of a new valve amplifier project. May I come in with a resounding no! Valves are passe and I don’t believe a progressive magazine like SILICON CHIP should waste resources on retro projects. All your golden-eared readers might be disappointed but they will both soon get over it. May I suggest that you look at some of the modern stage-lighting equipment which has been developed in the last few years. There is an opportunity to describe some of the modern moving head lights which are full of servos and electronics (and some of which use 22 control channels to control all the functions they have). You could cover the DMX512 standard which is used to control them and perhaps do a review of modern lighting control techniques (a historical retrospective could be interesting). This could then lead to a couple of projects, Power consumption in large-screen LCD TVs I would like to comment on the amount of power consumed by some large screen LCD TVs. I was surprised to learn that my recently purchased LG 42LC2D (42-inch) did not state the amount of power it draws from the mains. The current is stated to be 2A but no wattage rating is listed. Hence I did a little checking with a power meter loaned from my local TAFE College where I teach Industrial Electronics. The measured power consumption was around 250W, give or take around 20W depending on sound output, picture brightness, etc. Comparing this to a 70cm CRT-based LG TV, which measured around 60W, is a little disturbing. I am assuming the bulk of this power must be taken by the fluorescent tubes that provide the backlighting to the LCD screen. It makes 4  Silicon Chip one being a digitally controlled dimmer (or perhaps two, each using a PLC and one using phase control and the other using high speed PWM switching) and perhaps a DMX decoder. Another aspect is the use of LEDs for lighting. This could lead to another project to build a 3-colour mixing light for party effects. I love the magazine and read it assiduously. I have just been re-reading the 1994 issues and am amazed at the changes which have occurred since then. Bob Lions, via email. USB-UP revisited I recently built the USB-UP kit from the November 2004 issue of SILICON CHIP; it works great. On reading the Notes & Errata for the original publication, it seemed that there were only two ways you could get around the problem of your PC not powering down the USB ports when in “soft off” mode. These involved either buying a PCI USB card and using it you wonder how long these tubes will last at such high light output levels. It seems consumers are not aware of these hidden costs. True, the LCD screen is nice to watch, especially in widescreen highdefinition format but at what price? All this extra power is placing additional burdens on home air conditioning systems and may be compared to a similar problem caused by using quartz-halogen ceiling downlights. Someone had previously installed 12 of these 50W units in our living room. I soon replaced most of these with two modern high frequency 36W circular fluorescent lights and directly saved around 500W, while indirectly at least a kilowatt, considering air conditioning in the summer has to remove this extra heat. I also eventually found equivalents to the remaining 12V/50W quartz halogen lights such as the Megaman GU10 based 240V with that or switching the PC off at the mains/PSU. For those lucky enough, there is a third option. A number of motherboards allow you to choose where the power for the USB/PS2 ports comes from. There might be a jumper, (usually located near the PS2 ports), that you can use to select either +5VSB (5V Standby supply) or +5V (normal 5V supply). For ASRock motherboards, the default is +5VSB; moving it to +5V will remove power from the USB/PS2 ports when the computer is put into “soft off”. Of course, doing this will remove the ability to turn on the computer via keyboard or mouse. Dave Clarke, via email. CFL 11W units, giving a similar light output. In this energy-wasting consumerbased society, surely we should be looking at means of reducing energy waste. In short, I was disappointed at the relatively large power requirements of my LCD TV and certainly won’t be using it to provide background music on the many radio channels provided, especially if I cannot turn off the backlighting! I believe TV manufacturers should be made to display the power consumption of their products, as is required of white goods manufacturers; it may well lead to more energy efficient products. Heinz Harle, Liverpool, NSW. Comment: we commented on the amount of power used by plasma sets in the March 2006 editorial but it seems that LCD sets have a similar problem. siliconchip.com.au Electric drills and rechargeable batteries I agree entirely with your editorial in the December 2006 issue regarding portable drills. Unfortunately, as long as the portable drill market is profit-driven and rechargeable batteries are vulnerable, I suspect the situation won’t change very much. Of course making the public aware of the problem is important. A project like the charger controller must certainly help to do this but I think that the number of people who would actually build this controller, compared to the number of people who use portable drills, is in the minority. That puts the ball squarely in the court of the manufacturers – both the ones who make the drills and those who make the batteries for the drills. If the drill manufacturers aren’t motivated to fix this problem then I would call on the battery manufacturers to come to the party. I believe that the technology already exists whereby overcharging of their rechargeable batteries could be prevented – and fairly cheaply. For example, I can see no reason why a simple thermal cutout, such as a Advances in cars are real I was disappointed by Julian Edgar’s article “Electronic Advances in Cars?” in the December 2006 issue, since he fails to acknowledge the significant electronic advances in hybrid electric cars. His comments about the Prius could create an incorrect perception about hybrid vehicles and their role in reducing greenhouse gases. His article in June 2006 on “Allison’s Hybrid Drive Bus” was very good and appears to be factually correct, whereas his statements about the Toyota Prius suggest a lack of relevant research. His statement that “the NiMH battery pack is heavy and requires such a huge amount of energy to produce that it is doubtful if the energy savings in fuel over the life of the car outweighs the production energy input” prompted me to do some internet research on life cycle assessment and the hybrid battery technology. Firstly, the Australian Greenhouse siliconchip.com.au bimetallic strip, could not be incorporated in all rechargeable cells. The question then is what might induce the battery manufacturers to fix this problem, for which they are at least partly responsible? One solution might be for national standards bodies to require that some kind of protection be implemented in such products. They could justify this on the grounds that, without protection, a rechargeable battery cannot reasonably be expected to survive for the expected lifetime claimed by the manufacturer. All sorts of consumer products right now are provided with various means of protection to minimise harm or damage in the event of misuse or failure. They are provided with such protection because they are required by law to be so protected. So why should batteries be an exception? The bottom line is that neither the manufacturers nor the regulatory bodies will act if the consumers – we the public – don’t complain. If we do nothing then most likely nothing will be done. Herman Nacinovich, via email. Office published a report in May 2004 “Life-Cycle Emissions Analysis of Fuels for Light Vehicles,” that includes a 1998 Life Cycle Assessment prepared by Toyota on its hybrid vehicle versus a typical gasoline vehicle. The hybrid vehicle uses about 37% less energy over its life compared to a typical petrol vehicle. If Julian has documentation to the contrary could you please provide it? Secondly, would Julian explain why he thinks the Prius battery is too heavy? The battery pack in the Generation III Prius weighs only 45kg versus 57kg for the original Prius and its specific power is about 50% greater than what a panel of industry experts predicted in 1999 would be available in NiMH batteries by 2005 (“The Prospects for Hybrid Electric Vehicles, 2005-2020: Results of a Delphi Study”, Henry K. Ng, Anant D. Vyas, and Danilo J. Santini, Center for Transportation Research, Argonne National Laboratory). Atmel’s AVR, from JED in Australia JED has designed a range of single board computers and modules as a way of using the AVR without SMT board design The AVR570 module (above) is a way of using an ATmega128 CPU on a user base board without having to lay out the intricate, surface-mounted surrounds of the CPU, and then having to manufacture your board on an SMT robot line. Instead you simply layout a square for four 0.1” spaced socket strips and plug in our pre-tested module. The module has the crystal, resetter, AVR-ISP programming header (and an optional JTAG ICE pad), as well as programming signal switching. For a little extra, we load a DS1305 RTC, crystal and Li battery underneath, which uses SPI and port G. See JED’s www site for a datasheet. AVR573 Single Board Computer This board uses the AVR570 module and adds 20 An./Dig. inputs, 12 FET outputs, LCD/ Kbd, 2xRS232, 1xRS485, 1-Wire, power reg. etc. See www.jedmicro.com.au/avr.htm $330 PC-PROM Programmer This programmer plugs into a PC printer port and reads, writes and edits any 28 or 32-pin PROM. Comes with plug-pack, cable and software. 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 February 2007  5 Mailbag: continued Thirdly, based on my reading about hybrid electric cars and future plug-in hybrid electric vehicles, I would say the automotive industry has made substantial advances in electronic technology that would be the subject of an interesting article in SILICON CHIP. For example, the Panasonic battery used in the Prius battery is capable of over 10,000 charge cycles. Compare that to the 500 or so cycles we can get from consumer NiMH batteries. How about an article on the battery charging technology used in the Prius? The US Department of Energy sponsors research on renewable technology and I have found over a dozen very interesting publications about the Prius and hybrid vehicles at http://www.osti. gov/bridge. For example, researchers at the Oak Ridge National Laboratory have performed exhaustive tests on the battery packs in the Prius and Honda hybrids and the Prius engine and electronic controls. They even revealed the secret about how Toyota has increased the Prius motor output from the 33kW of the Prius Generation II to 50kW in the Prius Generation III using the same windings. I also want to comment on your editorial and article about the environmental wastefulness of cheap battery powered tools. Since Julian Edgar has implied that production of NiMH bat- teries requires huge amounts of energy, I’d like to suggest more articles on battery technology and the implications on greenhouse emissions. Robin De Vore, Myponga, SA. Comment: Julian Edgar owns a previous model Prius and is very familiar with the technology used in the car. In general, the thrust of the article is correct. For example, the latest Toyota Aurion is slightly smaller than the original Toyota Avalon that it replaces yet is heavier, has a more powerful engine but is no more economical. And yet the Toyota Avalon design is more than 10 years old. Sensationalistic journalism For many years, I have eagerly awaited each issue of SILICON CHIP. At times I have been tempted to write in for various reasons, usually for positive comments on excellent articles. However, as is usually the case with correspondence, I am writing with a complaint instead. I have read many articles over the years by Julian Edgar and have sometimes wondered about the integrity of his facts. The latest article titled “What’s Happened To Electronics In Cars?” has compelled me to write. I found it to be the most disgraceful piece of sensationalistic journalism that I have ever read in your magazine. I have been involved in the automotive field for many years, specifically in electrical and electronic systems, including spending time with a luxury vehicle importer, and also with a research team at Melbourne University. I am currently teaching to apprentice Mechanics and Automotive Electricians and feel that it is important to keep up to date with the latest trends in technology. The claim that “the only significant development in cars over the last decade has been the widespread fitting of stability control” is about a decade too late, as this was introduced nearly 20 years ago, by the very manufacturer shown in the first photo of the article. The advances in technology have not slowed down in the slightest. Just a quick search on the internet will show that there are manufacturers with various forms of direct petrol injection using a stratified charge (extremely lean mixtures) already in production, claiming excellent fuel usage reduction. This is not a piece of technology that falls in their laps but takes many millions of dollars and years of research to bring to market. There are definite limits to the current technology available, as was so well shown, but not expressed in the “Honda Insight” insert. Here was a FREE REMOTE CONTROL CAR * * See website for further details RS220 When you place your NEXT order online www.rsaustralia.com 6  Silicon Chip siliconchip.com.au SURPLUS ELECTRONIC COMPONENTS $1.00 SHARP 10mm Super Bright LEDs Lens: Clear Device: GLOZJ042BOS Colour: Red Lumin: 18500mcd W/Length: 618~627nm Typ. Voltage: 2.1~ 2.6V #27498 Device: GLOZV042BOS Colour: Yellow Lumin: 16900mcd W/Length: 588~591nm Typ. 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Clayton P.O Box 1189 Huntingdale Web Address: www.rockby.com.au ABN# 3991 7350 807 Victoria 3168 Email: salesdept<at>rockby.com.au ACN# 006 829 821 Victoria 3166 siliconchip.com.au February 2007  7 Ph: (03) 9562-8559 Fax: (03) 9562-8772 * Stock is subject to prior sale ROCKBY ICS ELECTRON ROCKBY ICS ELECTRON 5x7 Dual Colour Dot Matrix Display Y And Other Products See Y KB KB CSite: For C On-line Ordering Web www.rockby.com.au O RO ROur RONICS RONICS Mailbag: continued Car speedos can be wrong while odometer is correct The Speedo Corrector project from the December 2006 issue is a great idea for those with gearing/tyre size changes, etc. As you know, the error factor relates to both indicated speed versus real speed but also includes the odometer differences as well. In the middle of this comes a potential problem, as a result of recent changes to our Australian Design Rules. This has allowed a greater error percentage of speedo accuracy and it seems that some manufacturers have taken deliberate advantage of this or used lower spec instrument panels in some cars. This translates to the speedo indi- car maker that did everything that Mr Edgar claimed would save the automotive world but it was simply rejected by consumers for various reasons. As far as all of the gadgets and gimmickry being a waste of money, I for one enjoy those little comforts that make motoring that little more pleasing. As far as using LCD displays for “looking” behind the vehicle when reversing, yes they are available. Another advancement manufacturers have been using is the integration of multiplexed wiring systems. While the reasoning is not purely to reduce the weight of wiring looms, this is one of the benefits being exploited as the price of raw copper continues to rise. Another major advancement, while not brand new, is the increasing versatility of on-board diagnostics to reduce down times and the cost of diagnosing the majority (not all) of the faults which may occur in a motor vehicle. One of the contributions that electronic throttles have made to the motor vehicle is not just to minimise “kangaroo hopping” but to also improve exhaust emissions. Advancements in lighting are continuous. LEDs are used on many vehicles for lighting. The use of gas discharge lighting for headlamps has made great improvements in the reliability and safety aspects of night driv8  Silicon Chip cating a higher speed than the car is actually doing on the road. My 2005 Toyota Yaris indicates about 108-9km/h for an actual road speed of 100km/h. Toyota has replaced the speedo once and the problem is still there. Interestingly, the odometer is accurate to within 100 metres over a 10km test run, confirmed with two GPS units; about a 1% error. Now if a Speedo Corrector was installed in my case, the speedo could be made accurate but the odometer would be registering low by 8-9% or so. This raises a problem with the legality of tampering with an odometer (by fitting the kit) to record LESS than the actual distance travelled. Could this lead to big fines? ing. Research continues into the use of LED lighting for headlamps and we can expect to see it in the near future. Electric power steering has helped reduce the weight and cost of vehicles using it, braking systems are continually advancing for added safety, and enormous amounts of research continues in the field of batteries for the eventual possibility of fully electric vehicles. The amount of research carried out in the automotive sector runs into billions of dollars yearly. In conclusion, I was bitterly disappointed with the article and I feel that it completely lacked even the most basic of research. Petar Maksimovic, Redwood Park, S.A. Comment: we don’t dispute that there have been many technological developments in cars over the years and in fact we have covered most of them in the magazine. However, in spite of those developments, today’s cars are becoming very heavy and while engines are certainly more refined, the weight gains have mitigated against better fuel economy. By the way, multiplexed wiring is not new. We wrote about multiplexed wiring in the Jaguar XJ-40 in the February 1988 issue of SILICON CHIP and we covered Direct Petrol Injection in August 2005. However, cars with this I also have to ask why a Government would allow such error margins in new car speedos. As my wife discovered, she was being regularly tail-gated on the highway when driving at an indicated 100km/h, when in actual fact she was only travelling at 92km/h road speed. How safe is that? Funnily enough, our Yaris uses the same digital instrument technology as our previous Toyota Echo, which had a speedo accurate to just within than 2%. Jack Chomley, via email. Comment: thanks for the warning Jack. People using the Speedo Corrector to correct a speedo in an otherwise unmodified car should be aware that it could lead to odometer error. latter feature, such as Alfa Romeos, do not appear to be any more economical than cars without it. Nor are cars with electric power steering necessarily any lighter than cars with conventional power steering. No doubt cars could be designed to be much lighter and economical – but they are not! SLA batteries for portable drills I read with interest your article on cheap electric drills. Often when you contact the manufacturer you will find that the replacement battery pack is worth more than a new drill. My solution is to pick up several 12V 7.7Ah sealed cell batteries and hook the drill up to them with a cable. Sure it is not cordless but it is still portable. With some Nylon strapping and Araldite, it’s easy to put a carry handle on the battery for additional portability. I now have three drills modified like this and the 12V batteries last far longer than the original units. David Boccabella, via email. Bringing a dead cordless drill back to life I liked the article on reviving cordless drills in the December 2006 issue siliconchip.com.au Valve amplifiers not wanted “Do People Really Want a High-Performance Value Amplifier”? God NO! Is this the legacy of “Electronics Australia” and “ETI”? This letter has been building in me for some time but your November 2006 editorial has finally convinced me to write. Can we please at least try to drag SILICON CHIP out of the 1950s, full of old fogey’s memories of Vintage Radio and the dawn of television? Comparing SILICON CHIP to, say, the US-based “Circuit Cellar” or the UK’s “Elektor” is truly disheartening. Isn’t this the descendant of the magazine which brought us the EDUC-8? The Playmaster? Miniscamp? And what do we have now? A PIXaxe Web server? Modchipping an Xbox? Programmable Christmas Star? Tachometer kits! In the 1970s and 1980s Australia was the backwater of electronics, where local monopoly component suppliers weren’t even interested in you without a 1000+ component order and ordering overseas was a hideous experience. Despite this, ETI and EA managed to produce some fascinating designs and projects and built a market around those limitations. Today, we can order pretty much any part from anywhere in the world. We have FPGAs which can implement designs orders of magnitude more complex than the largest 80s-era ASIC. Surface mounting can be done by hobbyists and regularly is (in other magazines anyway). We can easily order multi-layer PCB boards over the internet for affordable prices and have them couriered to our homes. We can download free SDKs and silicon compilers over the internet . . . but we don’t. We talk about valve amplifiers and articles which include PICaxes with 20-line “firmware”. There should be a mix of the complex and the simple, the cutting edge and the pedestrian, the risky and the straightforward. So why does SILICON CHIP only include simple, pedestrian and straightforward? What’s happened? Where is the legacy of EA and ETI? Does it still live, or is it RIP? Ian Farquar, via email. Comment: SILICON CHIP does produce projects which do require a lot of development. An example is the Digital Volume Control in this issue. And we have produced designs with surface-mount components such as the UHF Prescaler in the October 2006 issue. Interestingly, none of the kit suppliers has so far seen fit to make a kit available for this project. but I think that it is the most expensive way to go; ie, buying more expensive Nicad cells which maybe will last for a couple of years. I have been doing a similar thing by using SLA batteries. I take the original battery pack apart as you have done and then make a dummy battery pack with wood dowelling inside to hold the contacts and then wire them siliconchip.com.au Save Up To 60% On Electronic Components Great New ET-AVR Stamp Only $26.47 * Includes ATMega128 Microcontroller * Up to 53 I/O Points * 8-Channel 10-bit A/D * Direct In-Circuit Programming * Ideal as a Removable Controller Exciting New ET-ARM Stamp * Includes LPC2119 Microcontroller * High-Speed Operation * Heaps of I/O plus CAN, UART, I2C * In-Circuit Programming * Supporting Board Also Available Only $33.12 Save Heaps on Components Only $7.85 We carry a wide range of Integrated Circuits, Microcontrollers, Capacitors, LEDs and LCDs. All at very competitive prices. We are your one-stop shop for Microcontroller Boards, PCB Manufacture and Electronic Components. www.futurlec.com.au “MERLIN” Safe External Switchmode Power Supply Practical and Versatile Mini Broadcast Audio Mixer Broadcast Quality with Operational Features and Technical Performance identical to full sized Radio Station Mixing Panels Permanent Installation is not required, the “Merlin” is as easy as a Stereo System to “Set Up”,all connections via Plugs and Sockets The “Merlin” originally designed for Media Training use in High Schools and Colleges is a remarkably versatile Audio Mixer Applications: Media Training - Basic Audio Production - News Room Mixer - Outside Broadcasts - Radio Program Pre Recording On-Air Mixer in small Radio Stations - “Disco Mixer” The “Merlin” is an Affordable Professional Audio Product Buy one for your School, College, Community Radio Station, Ethnic Radio Broadcast Association or for yourself For Details and Price, please contact us at ELAN Phone 08 9277 3500 AUDIO Fax 08 9478 2266 2 Steel Court. South Guildford email sales<at>elan.com.au www.elan.com.au Western Australia 6055 February 2007  9 Mailbag: continued PICs and the changing face of electronics I’ve just finished reading the December 2006 magazine - congratulations on another great issue! But it made me think: are PICs (and small microcontrollers in general) taking the “electronics” out of modern electronics? I admit that this is a bit rich coming from someone who has contributed a PIC-based project! I admire ingenious electronic design and I like to pick up design tips by closely examining the circuits you publish, and reading the “How it works” section of each project, even if I have no real interest in the project’s application. But increasingly, we see for example, in the Power Tool Charger Controller “apart from the PIC, there is not really much else to the circuit”. The CPR Trainer also consists of little more than a PIC there is very little the article can say about how it works. to a microphone line plug (Dick Smith Electronics Cat. P-1820) which is polarised so you cannot make a mistake when connecting them together. These work best with 12V, 18V and 24V drills, as you can best match the voltage with these. I have found that the charge will last about twice as long as the Nicad packs. By having two or more of these packs, when one is charging you can use the other and always have plenty of charged, batteries on hand. The only drawback is that you have to carry the SLA battery with you when you are working. I put the SLA battery into an aluminium box or a sealed polycarbonate box and then put a strap onto it to sling it over my shoulder. A. Prince, via email. Vintage TV needs a good home I have a 1974-76 Philips colour TV, 68cm with working remote. It’s still working with a good picture and is 10  Silicon Chip Then there’s the Super Speedo Corrector - a little more electronics of interest, giving some scope for explanation about being configurable to different voltage levels, noise filtering, etc but what would be really interesting would be to know how the frequency conversion is performed. To say “[the PIC] is programmed to alter an incoming frequency” isn’t really a satisfying explanation. On the other hand, we see circuits such as the Auxiliary Battery Controller which features just the sort of hard-wired logic that a small PIC could replace very easily and cheaply. All the NOR and NAND gates, and associated diodes, resistors and capacitors could be readily replaced with a little 8-pin PIC – lowering cost, reducing board space, and increasing reliability. And yet there does seem a loss of the “art” about that. It seems somehow more clever to build an oscil- in very good condition. I would like to sell it to someone willing to clean up/restore but can’t find anyone interested. Can you help? Colin McIntosh, Melbourne, Vic. Phone 0407 333 838. Recycling microwave oven components Readers of the “Salvage It” article on microwave ovens and your editorial on the wastefulness of electronic equipment being dumped (December 2006) may like to know that a lot of electronic scrap is recyclable. While microwave oven transformers may have no other safe purpose in electronic projects, they are recyclable, due to the amount of steel and copper in them. Many scrap metal yards will pay 20-40 cents per kilogram for them, and will happily take the steel chassis of the appliance too. Most of these transformers weigh 5-7kg each; maybe not worth it for one or two of them but worth checking out for repair workshops who have lots of lator to flash a LED out of a NAND gate and a few passive components, than it is to write a few lines of code. It’s similar to the feeling I get looking at the Vintage Radio column and trying to follow the circuit descriptions, with my limited knowledge of valves. It seems very clever, the way a single valve can accomplish several tasks at once. Such design seems to be a lost art. Yet again, looking at the remote watering system described in Circuit Notebook (December 2006, page 4243), I see a bunch of counters and gates, all cleverly laid out, and yet there are four chips that could effectively be replaced with a single PIC. In fact, make that six chips, because the PIC could also provide the delays produced by the 555s. So I guess I am saying the PICs are taking over and deservedly so but I say that with some regret. What to do? No use fighting the tide. But I’d like to see more explanation of what the PIC code is doing. David Meiklejohn, via email. scrapped microwave ovens to dispose of. My local scrap yard also buys scrap computer/electronic circuit boards at 20c/kg and computer hard drives at 20c/kg as Fe-Aluminium. Save money on tip fees, help the planet and make a few dollars at the same time. Andrew Peters, Rockhampton, Qld. Loved the Boony story Our company did the software development for the Boonanza II online promotion. I loved your article on this year’s talking figurines in the January 2007 issue but thought you might be interested to know that the website FAQs do point out that they wouldn’t respond to the television like the first Boonanza promotion. See: http://www.boonanza.com.au/dpages/ faq.html#faq11 By all accounts the original figurines did respond to the TV and as I understand it was done via an audible tone broadcast with the TV signal. James Macpherson, SC www.nextstudio.com.au siliconchip.com.au Viganella: solar power with a twist! Let there be light – and there is! by ROSS TESTER D eep in Italian Alps lies the tiny town of Viganella. It’s about as far north as you can get in Italy before you cross into Switzerland. But the Bishop who founded Viganella in the early 13th century made a fundamental error in siting the town. It didn’t occur to him at the time – midsummer 1217 – that the idyllic location between two streams near the bottom of a deep valley would also be the cause of eight centuries of winter misery. For most of the year, Viganella is beautiful. Picture postcard, even. But for 84 days in winter (November 11 to February 2) the village is completely in the shadow of a 1100m high peak to the south and receives no sunlight whatsoever. While that doesn’t translate to darkness, it does – or at least did – mean a gloomy existence, making Viganella very much less than ideal during winsiliconchip.com.au The concept is delightfully simple: place a mirror high enough up a south-facing mountain so that it can “see” the sun, normally hidden behind a tall mountain to the south. Angle the mirror so that it reflects the sun back down into the shadows and . . . ecco! (that’s Italian for voila!). But it took some seven years and 100,000 euros (approx. $AU165,000) to bring the concept to fruition. February 2007  11 For most of the year, Viganella is an idyllic place to live, nestled high in the Italian Alps (above). But come late November, it used to be plunged into gloom and perpetual cold until the sun reappeared in February – the most frustrating part was the brilliant sunshine only a couple of hundred metres away on the mountains above. ter. Temperatures plummeted, flowers died and laundry took an eternity to dry naturally, if at all. It seemed so unfair. The villagers could see brilliant blue sky above, could see the bright sunlight on the mountains overhead – yet they were destined to live in shadow. Most of the town’s 185 residents didn’t venture outside during the days of perpetual gloom. They re-emerged only for one of the town’s main festivals, held early February to mark the return of sunshine to Viganella. Many, especially the younger ones simply left town, leaving only the elderly behind. Fewer and fewer children were born, until Viganella faced the threat of extinction. Even the health of those residents that remained in Viganella suffered with a condition known as SAD – “Seasonal Affective Disorder”, whereby the lack of sunshine reduces a person’s production of melatonin, a natural hormone, making them depressed. Today, though, it’s different. While ever there is a cloudless sky, Viganella is bathed in sunshine for up to six hours each day. That mightn’t sound like much to plains dwellers but it certainly does to Viganellans! So what has changed? In a classic twist to the old proverb about moving Mohammed and mountains, Viganella resident – and now From the Viganella council’s files, this diagram shows the concept diagram for the heliostat system. The final execution looks slightly different . . . 12  Silicon Chip Mayor – Pierfranco Midali brought the sunshine to the village by erecting what is believed to be the world’s first, and only, heliostat (or mirror if you like) intended specifically for light. It’s mounted high on the 1100 metre Mount Scagiola on the northern side of the valley, catching the sun’s rays from the south and reflecting them back down into the depths of the valley – and Viganella. The village is illuminated (and warmed!) by the reflected sun rays for between five and six hours each day – assuming, of course, that the sun is shining! It’s centred on the town square or piazza. The villagers call the square “Il Cuore di Viganella” – the heart of Viganella. . . . and this is it, perched about 500m above the town on Mt Scagiola. The 5 x 8m mirror is made of steel and computercontrolled motors allow it to track the sun’s movement. siliconchip.com.au Viganellans waiting for the sun to, umm, rise? The mirror gives about 5-6 hours of sunlight in the village each day. The heliostat, made of steel, is about 40 square metres (8 x 5m). It tracks the sun’s progress across the sky with the aid of computer-driven motors so the sunlight is always aimed at the village. Architecht Giacomo Bonzani did some experiments in his back garden to prove the theory. And the mirror on Mt Scagiola is the end result. “On a clear day it produces five hours of sunlight in the piazza even in midDecember,” he said. “In theory, it could be snowing in the village but so long as the sun was out further up the valley, Power Supplies Here’s another view of the system on the mountain. Presumably this photo was taken during construction. Viganella’s piazza could have snow and sunshine at the same time.” The giant mirror was ferried to the site by helicopter and installed last November. A big inauguration party was held on December 17, close to the Winter Solstice. Residents wore sunglasses in commemoration of the event and the vision of their mayor. Midali, a former railwayman, took seven years to raise the 100,000 euros to bring the idea into reality, getting himself elected Mayor of in the process. Oscilloscopes RF Generators As this issue of SILICON CHIP goes to press, Viganella is in the old “gloom” period but latest reports have the residents – especially the elderly – sitting outside in Il Cuore di Viganella enjoying the winter sun and warmth. Interest in the Viganella sunshine project has come from many other similarly-affected villages in The Alps, on both sides of the Italian/ Swiss border. Mayor Midali might just have spawned a whole new SC industry! Frequency Counters Spectrum Analysers HAMEG Instruments have always been recognised for the consistent quality and nocompromise value of German engineering. And now the news is even better! With more new products, an attractive educational discount scheme and lower prices for 2007 you owe it to yourself to find out more. Call us please on 1-300-853-407 Test Equipment: Sales, Service and Calibration siliconchip.com.au 1-300-853-407 www.triosmartcal.com.au February 2007  13 “Naked” WiFi World Record If, like many WiFi users, you’re struggling to get garden-variety, unamplified WiFi signals to reach the other end of your house (despite the manufacturers’ 100 or 200m claims!) you might be interested to know that a group in Venezuela has raised the WiFi distance bar a tad – without using amplifiers or other cheats! by Ermanno Pietrosemoli With the sleet stopped and the fog lifted, the 2.7m dish on top of Pico del Aguila stands ready for its part in the world record. The fine rope seen coming from the centre of the dish was used to help aim it towards El Baul, 280km away. 14  Silicon Chip siliconchip.com.au The Radio Link window showing the 280km path parameters overlaying the map of Venezuela showing the world-record distance. The two sites stayed in contact via cell phones. There has been a longer 2.4GHz link but it used amplifiers and a stratospheric balloon! T he world record for 802.11 data transmission (WiFi) is (at time of going to press) 310km. However this record was set by the Swedish Space Agency using 6W amplifiers and a stratospheric balloon. Using “naked” out-of-the-box equipment (albeit into dish antennas) and a ground-to-ground link, US radio amateurs achieved a distance of some 200km back in 2005. Thanks to a favorable topography – high mountains with plains in between – Venezuelans have already achieved some long-range WiFi links, such as the 70km between Pico Espejo and Canagua and a trial 100km link between Maracaibo and Machiques in Zulia State. But the record books have been rewritten by a group in Venezuela with a distance of some 280km. To put it in an Australian perspective, that’s roughly the distance from Sydney to Canberra! siliconchip.com.au Here’s how they did it. To break the record, the first step was to find a clear link path, ideally between two elevated areas with no peaks or other obstructions in between. Many sites in the Guayana region were looked at – even though the famous “tepuys” (tall mesas with steep walls) looked promising there were always obstacles in the middle ground. Attention was then turned to the mighty Andes mountains whose steep slopes, rising abruptly from the plains, looked adequate to the task. First examined was Pico Espejo (at 4765m above sea level) and several sites in the Amazonas State but there were again obstacles in the path. Using the free software Radio Mobile, (available at www.cplus.org/ rmw/english1.html), there appeared to be no obstruction along the whole 300km path between Pico Espejo and the town of El Baul, in Cojedes State. However, Pico Espejo can only be reached by cable car, making the transportation of a 2.4m dish rather difficult. An alternative mountain, Pico del Aguila, has road access to the summit, so this peak was chosen instead. Several sites were considered possible on and around this peak. Antennas While it would have been easiest to use 30dBi gain commercial antennas the group decided instead to recycle parabolic reflectors formerly used for satellite service, replacing the feed with a 2.4GHz one. The concept was proved with an 80cm dish but the gain was way too low, so they next tried an offset-fed 2.4m reflector. This offered ample gain, albeit with some difficulties in the aiming of the February 2007  15 Accordingly, it was not difficult to persuade Dr Sandro Radiciella, the head of the Aeronomy and Radio Propagation Laboratory at ICTP, to support Carlo Fonda’s trip in early April to Venezuela in order to participate in the experiment. Back home, Ermanno noticed a 2.75m parabolic centre-fed mesh antenna at the home of a neighbour, who graciously lent it for the experiment. Action Plan All smiles after the new world record was confirmed and the dish dismantled. The author of this article, Ermanno Pietrosemoli, is at the left in this photo, alongside Javier Triviño. 3.5° beam. The 22.5° offset also meant that the dish appeared to be pointing downwards when it was horizontally aligned. Several tests were performed with cantennas as feeds and also using a 12dBi Yagi. They were able to establish a link with the Base Station at Aguada but efforts to measure the gain of the setup using Netstumbler were not successful. There was too much fluctuation on the received power values of live traffic. Evidently, for a meaningful measurement of the gain, a signal generator and spectrum analyser were required and would also be needed for the field trip in order to align the antennas properly. While waiting for the required equipment, they looked for an antenna to be used at the other end, as well as for a pointing system better suited to the narrow radio beam. In February 2006, Ermanno travelled to Triest to partake in an annual wireless training event. While there he mentioned the project to colleague Carlo Fonda who was thrilled and eager to participate. The collaboration between the Latin American Networking School (EsLaRed) and the Abdus Salam International Centre for Theorethical Physics (ICTP) in the wireless field goes back to 1992, when the first Net16  Silicon Chip working School was held in Mérida with ICTP support. Since then, several activities in which members of both institutions have participated have taken place, notably the yearly training in wireless networking at ICTP and the ones dedicated to computer networks in general organised by EsLaRed in several countries of Latin America. Once satisfied with the existence of a suitable path, the group looked at the equipment needed to achieve the goal. Well-known Orinoco 802.11 (WiFi) cards have been used for a number of years. They are robust and trustworthy, sporting an output power of 15dBm and receive threshold of -84dBm. The free space loss at 282km is 149dB, so to compensate 30dBi antennas would be needed at both ends and even that would leave very little margin for other losses. On the other hand, the popular Linksys WRT54G wireless router runs Linux and the Open Source community has written several firmware versions that allow for a complete customisation of every transmission parameter. In particular, OpenWRT firmware allows for the adjustment of the acknowledgment time of the MAC Conditions atop the 4100m Pico del Aguila were not particularly pleasant. Here the team led by Carlo Fonda assembles the 2.7m mesh antenna in the middle of driving sleet and fog. siliconchip.com.au Transporting a 2.7m dish on the roof of a large 4WD is not without its perils . . . beware of low-flying trees! This was the dish taken to the top of Pico del Aguila. layer, as well as the output power. Another firmware, DD-WRT has a GUI interface and a very convenient site survey utility. Furthermore, the Linksys can be located closer to the antenna than a laptop, so they decided to go with a pair of these boxes, one as an AP (access point) and the other as a client. The WRT54G can operate at 100mW with good linearity and can even be pushed up to 200mW – but at this value non-linearity is very severe and spurious signals are generated, so this is discouraged. Although this is consumer-grade equipment and quite inexpensive, after years of using them the group felt confident that they could serve the purpose, provided a spare set was kept handy. By setting the output power at 100mW (20dBm), the Linksys still had a 5dB advantage compared with the Orinoco, so a pair of them was used. previously surveyed area at Pico del Aguila in a truck carrying the 2.7m mesh antenna. The Aguila team was able to install and point the mesh antenna before the fog and sleet began, as is common at this altitude of 4100m above sea level. Power for the signal generator was supplied from the truck by means of a 12 V DC to 120V AC inverter. Communication between the two sites was maintained via cell (mobile) phones – both ends have cell phone towers. At 11am in El Baul they were able to observe a -82dBm signal at the agreed 2450MHz frequency on the spectrum analyser. To be sure, they asked Carlo to switch off the signal and indeed the trace on the spectrum analyser showed only noise, confirming that they were really seeing a signal that originated some 280km away. After again turning on the signal generator they performed a fine pointing in elevation and azimuth at both ends. When they were satisfied that had attained the maximum received signal, Carlo removed the signal generator and replaced it with a Linksys WRT54G wireless router configured as an Access Point, while Javier connected another WRT54G at the opposite end, configured as a client. At once, they started receiving “beacons” but the ping packets did not get through. This was expected, since the propagation time of the radio wave over a 300km link is 1ms and therefore it takes at least 2ms for an acknowledgment to reach the transmitter. Fortunately, Open-WRT firmware allows for tinkering with the ACK timing and after Carlo adjusted for the three orders of magnitude increase in delay above what the standard Wi-Fi link expects they began receiving packets with delays above 5ms. Several .pdf file transfers from Carlo’s to Javier’s laptops were made to prove the world-record-breaking SC link. Doing it! Javier Triviño and Ermanno Pietrosemoli travelled to Baúl with a 4-wheel-drive truck loaded the offset antenna. Early next morning the antenna was installed and pointed in the direction of Pico del Aguila. The Garmin III plus GPS showed a total path length of 279km. At the same time, the other team, comprising Carlo Fonda and Gaya Fior from ICTP, with assitance from Franco Bellarosa, Lourdes Pietrosemoli and José Triviño, rode to the siliconchip.com.au Proving it: screenshot of Javier’s laptop showing details of .PDF file transfer from Carlo’s laptop 280km away, using two WRT54G wireless routers and no amplifiers. Note the ping times as well. February 2007  17 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: dicksmith.com.au Remote Volume Control & Preamplifier Module This up-to-date control module works with any universal infrared remote and features a blue LED readout and an optional rotary encoder. Its ability to both attenuate and amplify means that it can operate as a simple volume control or as a highperformance stereo preamplifier! S INCE THE PUBLICATION of our previous general-purpose remote volume control project (June 2002), a number of readers have requested a comparable unit with digital, rather than analog, attenuation. In other words, they want to dispense with the potentiometer, citing the short operational life and poor channel-tochannel tracking of these mechanical components. For those that haven’t seen the 24  Silicon Chip earlier project, a dual-gang motorised potentiometer was driven by a microcontroller to selectively attenuate the incoming audio signal. The advantage of this approach is simplicity and (depending on the pot used) relatively low cost. We used this method again in the Studio Series Preamplifier Control Module (April 2006), where we showed how it is possible to achieve both reliability and high performance using a more expensive motorised potentiometer. Nevertheless, we con-tinued to receive requests for a digitally attenuated version – so here it is! Now you’ve no excuse not to do away with that noisy old pot and upgrade to this state-of-the-art digitally controlled module – which should never wear out! Main features The Remote Volume Control & Preamplifier Module allows volume and balance adjustments to be made with any universal infrared remote control. Adjustments can also be made via an optional up-front rotary encoder. The encoder we’ve selected has 20 detents per revolution and a positive, professional feel. The volume and balance levels are displayed on a blue or red 2-digit read­ out, which can be set to “go blank” shortly after each adjustment for less siliconchip.com.au Pt.1: By PETER SMITH Also featured is a new, low-noise power supply module that includes its own on-board transformer. If the long slim board layout doesn’t suit your case, then the PC board has been designed so that you can slice off the transformer and juggle the two modules about to your heart’s content. But wait – there’s more! For those who already have a suitable chassis-mount transformer, we’ve also included a version of the supply without the transformer to save you having to cut the board apart in the first place! OK, so this new design uses a digital rather than analog volume adjustment method. To understand how this works, let’s look briefly at a basic attenuator and then compare this to the internals of the PGA2310. Digital control invasive operation. Muting is also supported via remote control. Due to its universal nature, the module can be used in-line in just about any hifi audio system. For example, it could be inserted between your CD/ DVD player and power amplifier – and would be ideal for use with several of our past audio amplifier projects, such as the SC480 (Jan./Feb. 2003) and the Studio 350 (Jan./Feb. 2004). The design is essentially a 2-chip solution, with the audio side handled by a high-performance Burr-Brown PGA2310 stereo audio volume control IC. An Atmel ATmega8515 microcontroller manages the user interface, which comprises the rotary encoder, two optional selection switches, an infrared remote control receiver and two 7-segment displays. It also communicates with the PGA2310 over a 3-wire serial interface to set the device’s volume levels. The two displays mount on their own small PC board and are wired back to the module via ribbon cable. All other components mount on the main board, which is designed to fit directly behind the front panel of a metal enclosure. This arrangement affords flexibility and simplifies construction for the majority of case assembly options. siliconchip.com.au Digital attenuation of an audio signal is quite straightforward in concept. In its simplest form, an attenuator might consist of resistive voltage divider whose elements can be selectively switched in and out of circuit under digital control. A basic representation of such an attenuator appears in Fig.1. With neither of the switches (S1 & S2) closed, the attenuation of the circuit can be expressed as: VOUT/VIN = (RB1 + RB2 + RB3)/(RA + RB1 + RB2 + RB3). Applying a digital logic “high” level to the control input of either switch causes it to close, bypassing a branch of the string. For example, if S1 closes, resistors RB2 & RB3 are bypassed, so the expression becomes: VOUT/VIN = RB1/(RA + RB1). As you can see, the circuit has three possible states or levels of attenuation. To increase the number of states, it’s just a matter of adding more resistors and switches. For audio use, the resistor values would be chosen so that each state change results in a logarithmic change in the attenuation level. Why the op amp? It acts as a buffer, isolating the circuit from output loading effects and generating a constant output impedance regardless of attenuation level. Programmable gain As mentioned, this design is based around the PGA2310 IC from BurrBrown (Texas Instruments) – see Fig.4. It integrates a digitally programmable attenuator that operates in much the same way as our example in Fig.1. However, this device is a little different in that the gain of its op amp is also digitally programmable. This means that it can be programmed to operate as an attenuator or an amplifier. Its overall adjustment span is 127dB, ranging from -95.5dB to +31.5dB in 0.5dB steps. Gain changes are effected during audio signal zero crossings, eliminating the audible “clicks” that typically occur without this feature. Two identical channels are included, labelled (not surprisingly) “left” and “right”. The level of each channel is set by a 16-bit serial data word that is transferred via the device’s digital Fig.1: this simplified circuit represents the basics of a digitallycontrolled analog attenuator. Two analog switches (S1 & S2) are opened and closed under digital control to select the inputto-output attenuation level of the circuit. February 2007  25 26  Silicon Chip siliconchip.com.au Fig.2: the complete circuit diagram for the module, minus the display board. All analog functions are handled by the PGA2310 volume control chip (IC1), while microcontroller IC2 deals with the user interface. When a volume change is requested by the user – either via the infrared receiver (IC3) or the rotary encoder – the microcontroller interprets the request and sends the new data down a serial pipe to IC1. interface. The PGA2310 was designed specifically for professional audio work, boasting high dynamic range and very low noise and distortion. How it works We’ve endeavoured to keep construction as simple as possible, hence the use of just three ICs (see Figs.2 & 3). The microcontroller (IC2) handles all aspects of the user interface, which comprises the rotary encoder, infrared receiver IC3, the LED displays and pushbutton switches S1 & S2. In response to user commands, the micro sends the desired volume level to the volume control chip (IC1) via a “3wire” serial interface. The serial interface consists of the signal lines SDI (Serial Data In), SDO (Serial Data Out), SCLK (Serial Clock) and CS (Chip Select). Each serial data transfer from the micro to the PGA2310 (IC1) consists of a complete 16-bit word, comprising one byte for each channel. Those interested in the specific timing details will find them in the relevant datasheet, available from www.ti.com. The micro can immediately mute both channels by driving the MUTE input of IC1 low. It can also determine how a new gain setting is applied to the device’s control registers by controlling the ZCEN input. If this input is high, the gain is updated on the second zero crossing of a channel’s input signal. This minimises audible glitches on the output. Conversely, if ZCEN is low, the update is performed as soon as it’s received. Note that with high volume levels and no input signal, it may well be possible to hear clicks when altering the volume level. This occurs because the PGA2310 waits only 16ms for the two zero crossings and if not detected, the new gain setting will take effect with no attempt to minimise audible artifacts. siliconchip.com.au The analog interface side is extremely simple, consisting of just a handful of resistors, capacitors and RCA sockets (CON4-CON7). The left and right channel inputs are arranged so as to be as far apart as practically possible, with obvious benefits in the channel crosstalk performance (see performance panel). As shown, the signal inputs are capacitively coupled to prevent DC currents from flowing in the PGA2310’s attenuator circuits. The 100W series resistors provide a small amount of protection from input over-voltages and also interact with 100pF capacitors to ground to filter out high-frequency noise. Note that larger resistor values cannot be used here because they would degrade the PGA2310’s distortion performance. On the output side, 100W resistors isolate the PGA2310’s drivers from cable and amplifier input capacitance, thereby ensuring stability. They also provide a measure of protection from short-circuit signal lines. Again, coupling capacitors prevent DC currents flowing in the output circuit. Keeping noise at bay Apart from minimising external logic, the use of a large 40-pin microcon- Fig.3: there’s not a lot to the display board – just two commoncathode 7-segment displays and a 20-way header socket. Resistors in series with each segment (on the main board) limit LED current to less than 5mA; an important requirement, as IOH current for ports A & C must not exceed 100mA in total! Fig.4: this block diagram shows the internal functions of the PGA2310 volume control IC. Both the input attenuation level and op amp gain are digitally controlled. The attenuation/gain levels are set via the on-board serial control port logic, which receives its data from the microcontroller. February 2007  27 Fig.5(a): a basic representation of a rotary encoder. This also shows how the switch inputs are pulled up via resistors internal to the microcontroller. The program in the micro filters out switch contact bounce and interprets the ‘A’ and ‘B’ signals to detect shaft rotation and direction. troller also allowed us to dispense with the need for display multiplexing, as each LED segment can be driven by one port pin. This is an important element of the design because it eliminates a potential source of switching noise. The other area that requires careful design to keep noise at bay is the power supply. As you can see, we’ve used RC filters comprising 10W resistors and 1000mF capacitors on the ±15V rails to reduce noise to a minimum. Strictly speaking, these are not required when the module is powered from the supply described here. However, they ensure consistent performance if the Fig.5(b): the two out-of-phase switch signals from the rotary encoder generate a 2-bit Gray code, defining one complete electrical cycle. Some encoders will have more than one detent per cycle unit is to be powered from the auxiliary outputs of a power amplifier’s supply, for example. Conducted noise from the microcontroller is reduced by the inclusion of an LC filter in its 4.7V supply, made up of a 100mH choke (RFC1) and an associated 100mF capacitor. In additional, digital ground is connected to analog ground at one point only – ie, at the power input connector (CON1). To ensure that this strategy is effective, you must use heavy-duty hook-up wire for the power supply wiring, as described in Pt.2 next month. Schottky diodes (D1-D3) in series Performance • • Frequency response......................................... flat from 10Hz to 150kHz • • • • • • • • • Input impedance............................................................................ ~10kW Maximum input signal...................... 9.7V RMS (0dB gain), 250mV RMS (+31.5dB gain) Output impedance........................................................................... 100W Harmonic distortion .......................................typically .002% (see Fig.9) Signal-to-noise ratio..............................-120dB (20Hz-22kHz bandwidth) Channel crosstalk.............................. -126dB <at> 1kHz, -123dB <at> 10kHz Adjustment range.............. 127dB (-95.5dB attenuation to +31.5dB gain) Step size....................................................... 0.5dB or 1.5dB (selectable) Gain matching............................................................................. ±0.05dB Display resolution........................................................................... 1.5dB Note: except where noted, all measurements were performed with a 600mV RMS input signal at 0dB (unity) gain with the output driving a 50kW load. For crosstalk measurements, the non-driven input was back-terminated into 600W. 28  Silicon Chip with all inputs help to reduce the chances of blowing something up if the input wiring is accidentally reversed. With the excellent dynamic range of the PGA2310, the loss of 300mV or so in the supply rails has little effect on performance. Despite this protection, it’s still possible to make a mistake – such as feeding +15V into the +5V input. In this case, ZD1 will conduct and rapidly collapse the rail, while sending up smoke signals. Assuming that you spot these early on, disaster may well be averted! No special interfacing logic is required for the switches or rotary encoder, because the entire switch debouncing and decoding sequence is carried out in firmware. The same applies to the output of the infrared receiver module (IC3). Its serial data stream is interpreted in line with the Philips RC5 infrared protocol, using an accurately timed, high-speed sampling algorithm to ensure excellent long-range performance. Encoder basics If you’ve never used a rotary encoder, you may be wondering how they work. The simplest encoders consist of a multi-lobed cam that is used to operate two microswitches (Fig.5a). When the shaft connected to the cam is rotated, one of the switches opens and closes in advance of the other, depending on the direction of rotation. This generates a 2-bit Gray code at the switch output terminals, which can be interpreted by a microcontroller or other digital logic to determine shaft position and direction of rotation (see Fig.5b). siliconchip.com.au Fig.6: the low-noise power supply uses common 3-terminal regulators and features an on-board toroidal transformer. This transformer generates less radiation than larger chassis-mount units so it should be possible to build the whole lot into a relatively small case without having problems with induced mains noise. As you can see, the four Gray code states describe one complete cycle, with the detents occurring when both switches are off. The encoder used in this project has 20 cycles (or “pulses”) and detents per revolution, so the cycle repeats every 18° of rotation. Its direction of travel is indicated by the phase of the two signals, which are always 90° apart. The timing diagram applies to most 2-bit encoders that utilise one detent per cycle (equal pulses and detents per revolution). In fact, the microcontroller program expects this configuration, so if you’re thinking of sourcing an alternative part, be sure that it meets this criteria. Also, get a unit with 20 or more detents – any less will result in unnecessary knob winding! Many other configurations are available; two and four detents per cycle are common. For example, an encoder specified with 4 cycles/rev and 16 detents/rev has 4 detents/cycle and is unsuitable for use here – it would take four clicks (1/4 revolution) to make a single change to the volume or balance! Note also that some encoders have built-in switches. Such a device would be ideal for this project, because it would be possible to wire the BALANCE switch input (at CON3) to the encoder’s switch terminals, thereby dispensing with the need for a separate switch to select balance adjustment mode. Low-noise supply To ensure the best possible performance, we’ve designed a separate, low-noise power supply to match the Remote Control & Preamp module. It provides regulated ±15V and +5V outputs and could be used with a variety of other audio projects. As mentioned above, it even includes an on-board toroidal transformer to further simplify construction. As shown on the circuit diagram (Fig.6), the transformer’s two 15VAC secondary windings are connected in siliconchip.com.au February 2007  29 Fig.7: follow this diagram when assembling the control board. Fig.8: it should only take a few minutes to assemble the display board. Note how the decimal points go at the top of the readouts, rather than at the bottom. series to form a 30VAC centre-tapped configuration. Note the fuses in the secondary outputs – these are included because the voltage regulators’ builtin current limiting may be too high to protect a small 10VA transformer in the event of an output overload. Diodes D1-D4 and two 2200mF capacitors rectify and filter the secondary output to create ±21V DC (nominal) rails. The following LM317 and LM337 adjustable regulators then generate the complementary positive and negative supply rails. Their outputs are programmed to ±15V by virtue of the 100W and 1.1kW resistors connected to their “OUT” and “ADJ” terminals. We’ve used adjustable regulators in this design because the “ADJ” terminals can be bypassed to ground to improve ripple rejection, which we’ve done using 10mF capacitors. The associated diodes (D6 & D9) provide a discharge path for the capacitors should an output be accidentally shorted to ground. Two reverse-connected diodes Table 1: Resistor Colour Codes (Control Board) This is the completed display PC board assembly. The LED readouts plug into two single in-line header strips. 30  Silicon Chip o o o o o o o o o o Value 100kW 10kW 4.7kW 1.1kW 1kW 560W 330W 100W 10W 4-Band Code (1%) brown black yellow brown brown black orange brown yellow violet red brown brown brown red brown brown black red brown green blue brown brown orange orange brown brown brown black brown brown brown black black brown 5-Band Code (1%) brown black black orange brown brown black black red brown yellow violet black brown brown brown brown black brown brown brown black black brown brown green blue black black brown orange orange black black brown brown black black black brown brown black black gold brown siliconchip.com.au Fig.9: the noise and distortion sits at around .002% with a 600mV input signal. The datasheets quote a smaller THD+N figure but use a much larger input signal – so we’ve plotted a second line to show the difference with a 5V input signal. Watch the orientation of the diodes, IC sockets, polarised capacitors and shrouded headers (CON8 & CON9). Use only the resistor values specified for the LED displays – lower values could lead to damage to the microcontroller ports. (D7 & D10) across the output prevent their respective rails from being driven to the opposite polarity (eg, if a regulator fails). A 7805 3-terminal regulator (REG4) is used to generate the +5V rail. To reduce power dissipation in REG4, a second fixed regulator (REG3) is positioned “upstream” to reduce the DC input from 21V to 15V. While we could have just added a series resistor or even a transistor-based pre-regulator to achieve similar results, this arrangement is inexpensive and includes the regulator’s protection features in the case of an overload. Because the +5V supply draws power from only the positive side of the unregulated DC rail, a 390W resistor (R1) across the negative input is included to help balance the rails, so that they decay at similar rates at power off. Fig.10: the frequency response is – well – flat! Construction We’ll assemble the main PC board (code 01102071) first – see Fig.7. Begin by installing the three wire links using 0.7mm tinned copper wire, then install the resistors. Note that the 330W resistor values adjacent to CON9 on the overlay diagram are for blue displays only. If you’ve decided to use red displays instead, then substitute 560W values for 16 of the 330W parts as indicated. All of the diodes (D1-D5 & ZD1) can go in next, taking care to orient their cathode (banded) ends as shown. That done, all remaining components can be installed siliconchip.com.au Fig.11: channel-to-channel crosstalk could hardly be better. The left & right signal inputs are located at opposite ends of the chip – and we took maximum advantage of this in the PC board layout. February 2007  31 Fig.12a: follow this diagram when assembling the power supply board. Most constructors will not want to cut the board into two sections, so terminal blocks CON1 & CON4 won’t be required. The transformer should be secured to the PC board via the central mounting hole before its pins are soldered. Below: this view shows the fully-assembled power supply board. Don’t forget to fit the cover over the mains fuse. Table 2: Capacitor Codes in order of height, with attention to the following points: • Be sure to insert the 1000mF and 100mF electrolytic capacitors around the right way, following the “+” markings on the overlay. The 47mF units are non-polarised and can go in either way. • The notch in the IC sockets must match that shown on the diagram, as must the polarising notch in the two shrouded headers (CON8 & CON9). 32  Silicon Chip Do not plug the ICs into their sockets until after the power supply has been cabled in and tested (see the “Testing” section in Pt.2 next month)! • The terminal blocks (CON1-CON3) and RCA connectors (CON4-CON7) must be seated squarely on the PC board surface before soldering. • Seat the crystal (X1) all the way down on the board before soldering. Once in place, connect its metal case to ground via a short length of tinned copper wire (see photo). • The lead length and bend of the two LEDs and infrared receiver (IC3) Value mF Code IEC Code EIA Code 220nF 0.22mF 220n 224 100nF 0.1mF 100n 104 100pF NA 100p 101 22pF NA   22p   22 can be determined by trial fitting the assembly into its intended position. Display board There’s not a lot to the display board – just a socket for the two displays and a 20-way header (see Fig.8). The socket can be made by cutting down a longer single-in-line (SIL) header strip into two 10-pin sections. Make sure siliconchip.com.au Fig.12b: this alternative version of the power supply board is available for those who prefer to use a chassis-mounted toroidal transformer. This board is essentially an upgrade to the low-noise supply featured in the October 2005 issue and will run cooler than its predecessor thanks to larger heatsinks. This view shows the mounting arrangements for the heatsinks and the regulators at one end of the PC board. Be sure to fit the heatsink tabs through their matching board holes, so that the heatsinks cannot touch each other. that these are sitting perpendicular to the PC board before soldering. When plugging in the display modules, note that the decimal points go at the top, not the bottom of the readout. Also, make sure that you’ve got the polarising notch of the header (CON10) facing inwards towards the displays. Power supply The power supply can be constructed in a number of different ways. If you’ve elected to build the version with an on-board transformer, then you have the option of separatsiliconchip.com.au ing the transformer section from the remainder of the board before commencing construction (see Fig.12a). Most constructors will not need to do this – check your chassis layout for compatibility before reaching for a hacksaw! If using a chassis-mount transformer, then you may optionally choose the second (smaller) power supply board, which omits the on-board transformer, fuses and associated connectors (Fig.12b). However, the following text assumes that you are assembling the on-board transformer version. As before, install all of the low- Fig.13: here’s how to assemble the regulators to their heatsinks. The 7805 regulator (REG4) presents a special case; its screw should be inserted from the opposite side to that shown so that the screw head isn’t obscured by REG3’s heatsink. The PC board holes for the heatsink tabs should be drilled to 2.5mm. If this proves to be marginally too small to accept the tabs, you can use a jeweller’s file to remove just enough of the tabs to get a neat fit. The 390W 5W resistor should be mounted about 2mm off the PC board. profile components first, starting with the single wire link. Note that we’ve specified a singlepiece fuseholder assembly with cover February 2007  33 Parts List 1 main PC board, code 01102071, 109 x 78mm 1 display PC board coded 01102072, 49mm x 34mm 1 rotary encoder, 20 pulses/ detents per rotation (Altronics S-3350) (optional, see text) 1 2-way 5mm/5.08mm pitch terminal block (CON2) 2 3-way 5mm/5.08mm pitch terminal blocks (CON1, CON3) 1 10-way boxed header (CON8) (Altronics P-5010, Jaycar PP1100) 2 20-way boxed headers (CON9), (CON10) (Altronics P-0144A) 2 PC-mount RCA sockets, red insert (CON4, CON5) (Altronics P-0144A) 2 PC-mount RCA sockets, black insert (CON6, CON7) (Altronics P-0145A) 1 40-way or 2 x 32-way 2.54mm SIL header socket(s) (Altronics P-5400, Jaycar PI-6470) 1 7-way 2.54mm SIL header (JP1JP3) 3 jumper shunts 1 100mH choke (RFC1) 1 16-pin gold-plated IC socket 1 40-pin IC socket 4 M3 x 6mm pan head screws 4 M3 x 10mm tapped spacers 0.7mm diameter tinned copper wire for links Semiconductors 1 PGA2310PA stereo volume control IC (IC1) (Farnell 1212339) 1 ATmega8515-8P (or –16P) microcontroller (IC2) (Jaycar ZZ-8765) programmed with DAVOL.HEX 1 TSOP4838 (or equivalent) infrared receiver module (IC3) for the mains fuse (see parts list) – so be sure to fit this in the correct (F1) position. The other two fuses (F2 & F3) use low-cost fuse clips. Position the small retaining lug on each clip towards the outer (fuse end) side; otherwise proper fuse installation will be impossible. The 390W 5W resistor mounts vertically (see photos) and should sit about 34  Silicon Chip (Altronics Z-1611, Jaycar ZD1952, Farnell 491-3190) 1 4MHz crystal, HC49S package (Y1) (Altronics V-1219) 3 1N5819 Schottky diodes (D1D3) 2 1N4148 small-signal diodes (D4, D5) 1 1N4735A 6.2V 1W zener diode (ZD1) 2 127mm common-cathode 7-segment LED displays, blue (Jaycar ZD-1856) or red (Jaycar ZD-1855, Altronics Z-0190) 2 3mm red LEDs (LED1, LED2) Capacitors 2 1000mF 16V PC electrolytic 3 100mF 16V PC electrolytic 4 47mF 35V/50V non-polarised PC electrolytic (max. 8mm dia.) 4 100nF 50V monolithic ceramic 2 100pF ceramic disc 2 22pF ceramic disc Resistors (0.25W 1%) 3 100kW 16 560W (red displays) 1 10kW 1 330W 2 4.7kW 16 330W (blue displays) 4 1kW 10 100W 1 560W 2 10W Additional items 2 20-way IDC cable-mount sockets (Altronics P-5320, Jaycar PS-0986) 20-way IDC ribbon cable (Altronics W-2620) Pushbutton switch (optional – see text) Universal remote control (see text) Power Supply 1 PC board, code 01102073, 168 x 61mm (on-board transformer) 2mm proud of the PC board surface to aid in cooling. If the board has been cut into two parts, then you’ll need to run an insulated wire link between points ‘A’ & ‘B’ to reconnect the ground end of this resistor back into circuit. On a similar note, terminal blocks CON1 & CON4 need only be installed if the board was cut apart. Due to its size and weight, the –or1 PC board, code 01102074, 80 x 61mm (off-board transformer) 4 Micro-U 19°C/W TO-220 heatsinks with tabs (Altronics H 0637, Jaycar HH-8504) 2 3-way 5mm/5.08mm terminal blocks (CON1, CON2) 1 2-way 5mm/5.08mm terminal block (CON3) 4 M3 x 10mm tapped spacers 8 M3 x 6mm pan head screws 4 M3 nuts & flat washers 0.7mm diameter tinned copper wire for link Heavy-duty hook-up wire for lowvoltage wiring Heatsink compound Semiconductors 1 LM317T adjustable positive regulator (REG1) 1 LM337T adjustable negative regulator (REG2) 1 7815 +15V regulator (REG3) 1 7805 +5V regulator (REG4) 11 1N4004 diodes (D1-D11) Capacitors 2 2200mF 25V 105°C PC electrolytic 2 100mF 16V 105°C PC electrolytic 3 10mF 16V 105°C PC electrolytic 1 220nF 50V metallised polyester (MKT) 2 100nF 50V metallised polyester (MKT) Resistors (0.25W 1%) 2 1.1kW 2 100W 1 390W 5W 5% Additional items for on-board transformer version 1 15V+15V 10VA PC-mount toroidal transformer (Altronics M-4330) transformer must be firmly attached to the board using an appropriate self-tapping screw via the provided mounting hole before its pins are soldered. If this is done in reverse order, the PC board pads may delaminate! You have been warned. Leave the four regulators (REG1REG4) until last. These must be attached to TO-220 heatsinks before siliconchip.com.au 1 M205 250VAC PC-mount fuseholder w/cover (F1) (Altronics S-5985) 4 M205 fuse clips (F2, F3) (Altronics S-5983, Jaycar SZ2018) 2 3-way 5mm/5.08mm terminal block (CON4, CON5) 1 100mA 250VAC M205 slow-blow fuse (F1) 2 250mA M205 slow-blow fuses (F2, F3) Self-tapping screw for transformer mounting Mains connection hardware to suit Additional items for off-board transformer version 1 15V+15V 20VA (or larger) toroidal transformer (eg, Jaycar MT-2086) Mains connection hardware to suit Notes Note 1: the low-voltage version of the microcontroller is also compatible with this project and is available from Futurlec at www.futurlec.com. au, part number ATmega8515L-8PI (or –8PU). Note 2: The 100mA and 250mA slow-blow fuses can be had from Wiltronics Research, stock Nos. FU0312 & FU0314. Check them out at www.wiltronics.com.au. Rockby Electronic Components also carry the fuses, stock Nos. 14740 & 14743 – see www.rockby.com.au for more details. Note 3: to avoid assembly difficulties and ensure long-term reliability, all the 3-terminal regulators (REG1-REG4) used in the power supply should be recognised name-brand devices, such as On Semiconductor/Motorola, STMicroelectronics, National Semiconductor or Fairchild. being installed on the PC board. First, smear a thin film of heatsink compound to both the rear (metal) area of each device as well as the mating areas of the heatsinks. That done, fasten them to the heatsinks using M3 screws, nuts and washers as shown in Fig.13 but don’t fully tighten the screws just yet. Note that insulating pads should siliconchip.com.au Universal Infrared Remote Controls The volume control module is designed to work with most universal (“onefor-all”) infrared remotes. It recognises the RC5 protocol that was originally developed by Philips, so the remote must be programmed for a Philips (or compatible) appliance before use. Most universal remotes are provided with a long list of supported appliances and matching codes. To set the remote to work with a particular piece of gear, it’s usually just a matter of entering the code listed for the manufacturer (in this case, Philips), as detailed in the instructions. You’ll also note that different codes are provided for TV, CD, SAT, and so on. This allows two or more appliances from the same manufacturer to be operated in the same room and even from the same handpiece. This multiple addressing capability can be useful in our application, too. Normally, we’d program the remote to control a TV, as this works with the control module. But what if you already have a Philips TV (or a Chinese model that uses the RC5 protocol)? Well, in this case, you’d simply use a CD or SAT code instead – the control model can handle any or these! Let’s look at an example. To set the AIFA Y2E remote to control a Philips TV, you’d first press and hold “SET” and then press “TV”. This puts the remote in programming mode, as indicated by the red LED, which should remain illuminated. Now release both keys and punch in one of the listed Philips TV codes. For this project, code 191 works well. The red LED should now go out and the remote is ready for use. All universal remotes can be programmed in a similar manner but when in doubt, read the instructions! If the first code listed doesn’t work with the control module, then try another. Once the remote has been programmed, the control module must be set up to recognise the particular equipment address that you’ve chosen (TV, CD, SAT, etc). Details on how to do this are in the setup and testing section. Although this project should work with any universal remote, we’ve tested the following popular models: AIFA Y2E (Altronics A-1013), AIFA RA7 (Al­tronics A-1009) and BC3000 (Jaycar AR-1710, pictured). For all these models, the setup codes are as follows: TV = 191, CD = 651 (but not for BC3000 remote), SAT1 = 424 and SAT2 = 425. Note that the “mute” button doesn’t work for all codes and in the case of the AIFA Y2E, is missing anyway! In these cases, you may be able to use the “12” or “20+” buttons instead. not be used here, as they will impede heat transfer. Now slip each assembly into place in its PC board holes, taking care not to mix up the different regulator types. The tabs of the heatsinks should fully engage the holes in the PC board, such that all of the heatsink edge contacts the PC board surface. You may find that the PC board holes are fractionally too small to allow this to happen – if this is the case, use a jeweller’s file to remove just enough of the tab to get a neat fit in the holes (see photo). Finally, push the regulators all the way down the slots in the heatsinks and then tighten up the screws. The regulator leads can now be soldered, taking care that the assemblies remain in place when the board is turned over. Note that you’ll find it easier if the devices are mounted in a specific order, as follows: REG2 first, then REG1, REG3 & REG4. That’s all we have space for this month. Next month, we will complete the construction and describe the setSC up and test procedures. February 2007  35 CAR PROJECT 1: Simple Variable Boost Control For Cars With Turbochargers Note: early prototype board shown. Quite a few cars have turbochargers these days and these can provide even more performance if the turbo boost pressure is increased. However, you don’t want permanently increased turbo boost as it increases wear on the engine, so you need a variable boost control, as presented here. Design by DENIS COBLEY Fig.1: the circuit is based on just two transistors and a couple of diodes. It intercepts the standard boost signal from the car’s engine management computer (ECU) and stretches it so that the signal to the boost control solenoid has a longer duty cycle T HIS VARIABLE Boost Control is a simple circuit to modify the factory boost levels. It was designed in the first instance to suit a Subaru WRX but it could be adapted to many cars and FWDs fitted with turbochargers. It employs a small PC board and requires only four wire connections to the car’s electrical system. Before we go any further we should 36  Silicon Chip warn that if you want to fit this project, you must have a turbo boost gauge permanently fitted. Operating variable boost above factory set levels can blow your engine if you don’t know what the boost level is. How it works The Variable Boost Control is a simple interceptor – it “intercepts” the standard boost signal to the Boost Control Solenoid from the car’s engine management computer (ECU) and stretches it so that the solenoid signal has a longer duty cycle. Most factory boost control systems use a variable width pulse signal to control the boost solenoid. This operates at about 14Hz to suit a Subaru WRX (1998 model). While the circuit of Fig.1 looks simple, it works quite well and has been fitted to several cars. The ECU boost pulse waveform is fed to the input which has a 180W 1W pull-up resistor. This is sensed by the ECU as the boost solenoid’s coil. From there, the signal is fed via a 4.7kW resistor to the base of transistor Q1 which inverts the signal at its collector. The inverted signal charges a 2.2mF capacitor via a 1kW resistor and diode D1 only to be discharged via 10kW trimpot VR1 each time the signal at the collector of Q1 is pulled down to 0V. The net result is a roughly sawtooth waveform with a slightly rounded leading edge and gently sloping trailing edge, the steepness of slope being dependent on the setting of VR1. This fairly rudimentary pulse signal siliconchip.com.au is fed to the BD681 Darlington transistor (Q2) via a 22kW resistor which drives the boost control solenoid. Fast recovery diode D2 is connected from the collector of Q2 to the +12V line. It is included to damp the spike voltages generated each time Q2 is turned off. Incidentally, Q2 inverts the signal back to the same polarity as the input, so that it drives the boost control solenoid correctly. A BD681 Darlington transistor is specified for Q2 since it has a high collector voltage, high gain and an adequate collector current rating (4A) to carry the currents of typical boost control solenoids. Note that in some cases Q2 may need a small flag heatsink. Note also that this circuit has no protection against reversed supply voltage so if you connect the supply leads the wrong way, both diode D2 and the Darlington transistor are likely to be instantly destroyed. The current path will be via the Darlington’s internal reverse diode and D2. You have been warned! The circuit operation is clearly demonstrated in the scope waveforms of Fig.2. The top waveform (yellow trace) is the input signal, a series of negative-going pulses. The middle waveform (purple trace) is present at the cathode of D1 while the bottom trace (cyan) is the output waveform at the collector of Q2. Note that the negative going pulses of the output waveform are substantially longer than those of the input waveform. Our test waveforms were made while the circuit was driving a resistive load rather than a boost solenoid but the operation was otherwise the same as would occur in a car. Building it The Variable Boost Control is assembled onto a small PC board measuring Fig.2: the top waveform (yellow trace) is the input signal (a series of negativegoing pulses). The middle waveform (purple trace) is the signal at the cathode of D1 while the bottom trace (cyan) is the output waveform at the collector of Q2. 38 x 30mm. The wiring diagram is shown in Fig.3. Note that the BD681 should be laid flat down on the PC board so that the whole assembly can be sheathed in a piece of heatshrink sleeving. Apart from two wires being needed to connect the 10kW potentiometer (VR1), you will need four wires to connect the Variable Boost Control to your car. These are as follows: • +12V IGN – Red • Earth (chassis) – Black • Boost wire from ECU – Green • Output to Boost Solenoid – Blue The +12V IGN wire can be tapped from any point which is switched by the ignition switch. The Earth wire can be run to any convenient point on the car’s chassis. Then you will need to identify the wire from the continued next page Fig.3: here’s how to install the parts on the PC board. Take care with the polarity of the transistors and diodes. siliconchip.com.au Parts List 1 PC board, code 05102072, 38 x 30mm 1 BC547 NPN transistor (Q1) 1 BD681 NPN Darlington power transistor (Q2) 1 1N4148 small signal diode (D1) 1 FR307 3A fast recovery diode (D2) 1 2.2mF 16V PC electrolytic capacitor 1 10kW potentiometer (VR1) Resistors (0.25W, 1%) 1 22kW 1 4.7kW 1 1kW 1 180W 0.5W Fig.4: this is the full-size etching pattern for the PC board. February 2007  37 CAR PROJECT 2: A Fuel Cut Defeater For Cars With Variable Boost Control Note: prototype board shown. Are you intending to build the Variable Boost Control described earlier? If so, you will need to built this simple Fuel Cut Defeater (FCD) to eliminate the standard factory fuel cut which typically occurs at boost levels about 16-17psi. The unit is not adjustable, so no external controls are required. Design by DENIS COBLEY T HE FUEL CUT DEFEATER is another simple “interceptor” design. It modifies the signal from the engine’s MAP (Manifold Absolute Pressure) sensor and stops it from exceeding a particular level before feeding to the ECU. Therefore, the ECU does not sense the over-boost condition brought about by the Variable Boost Control and hence does not cut the fuel supply via the injectors. The circuit is built on a small PC board and there are just four external connections: ie, +12V, 0V (chassis), MAP sensor and the output to the ECU. The circuit (Fig.1) is very simple and is based on a TL072 dual FET-input op amp package. IC1a is connected as a unity gain buffer (with its output connected directly to the inverting input) so that there is negligible loading of the MAP sensor signal. Input protection for IC1a is provided by the series 10kW resistor and by diodes D1 & D2 which clamp any large signal transients. Level clamp IC1b and diode D3 act as a level clamp once the output signal from IC1a exceeds the threshold at pin 5 of IC1b, as set by the three resistors and 5.6V zener diode ZD1. In fact, IC1b works as an inverting comparator, with the voltage at pin 5 set to around +3.9V. For output signals from IC1a of less than +3.9V, the output of IC1b will be close to +12V and diode D3 will be reverse-biased. Hence, IC1b has no effect on the output signal from IC1a and it passes unmodified to the ECU, via the 1kW and 680W resistors. However, once the signal at pin 6 of IC1b exceeds +3.9V, IC1b’s output goes low (0V) and diode D3 will be forward biased and it will conduct to shunt the output signal to the ECU, clamping Variable Boost Control – continued from page 37 ECU to the boost control solenoid and cut it. This should be done around 50cm or more from the ECU to make it difficult to detect. The end going to the ECU goes to the green wire on the Variable Boost Control, while the end going to the boost solenoid goes to the blue wire on the Variable Boost Control. Note that these connections should be made with male and female bullet or quick connect crimp 38  Silicon Chip connectors to ensure the integrity of the connections. Using these also means that you can quickly restore the standard boost connection, if you need to. The Boost control pot VR1 needs to be installed on your car’s instrument panel. Setting the boost level As already noted, you MUST have a boost gauge fitted at all times to monitor the boost levels. Drive the car up a long hill in third gear and set VR1 to provide the required boost level. Warning: exceeding factory boost levels can reduce the life of the engine and transmission. Finally, note that you may need the companion Fuel Cut Defeater, described in this issue, to remove the factory fuel cut which is typically set to activate at boost levels above SC about 16 or 17psi. siliconchip.com.au Fig.1: the circuit is based on a TL072 dual op amp (IC1a & IC1b). IC1a operates as a unity gain buffer, while IC1b works as an inverting comparator. it to a level of about 1.4V. Thus the ECU does not see MAP signals above a certain threshold and so it cannot cut fuel as it normally would in an over-boost situation. This last factor means that it is extremely important to ensure that you always monitor the turbo boost on your car if you are using this Fuel Cut Defeater in conjunction with the Variable Boost Control. Assembly & fitting Assembling the PC board (see Fig.2) is straightforward but make sure that you install op amp IC1 and the diodes the right way around. When you have finished the assembly, check all your work and then connect a 12V supply to the PC board. Make sure that you connect the supply with the correct polarity otherwise you are likely to damage diodes D1 & D2 and the op amp. Check that the voltage at pin 8 of IC1 is +12V (or close to it), with respect to pin 4. The voltage at pin 5 should be close to 3.9V. Note that this setting is designed to suit a Subaru WRX and may possibly need adjustment to suit the MAP sensors in other vehicles. When installing the PC board in your car, the +12V wire can come from any point which is switched by the ignition switch. The Earth wire can be run to any convenient point on the car’s chassis. You will then need to identify the wire from the MAP sensor to the ECU solenoid. The one to use has about 1.4V on it at idle. Cut this wire at around 50cm or more from the ECU to make it difficult to detect. The end going to the MAP sensor ECU goes to the green wire on the Fuel Cut Defeater (FCD). The end going to the ECU goes to the blue wire on the FCD. Note that these connections should be made with male and female bullet or quick connect crimp connectors to Fig.2: follow this parts layout diagram to build the Fuel Cut Defeater. Note that diodes D1 and D2 face in opposite directions. siliconchip.com.au ensure the integrity of the connections. Using these also means that you can quickly restore the standard boost SC connection, if you need to. Parts List 1 PC board, code 05102071, 50 x 33mm 1 TL072 dual FET-input op amp (IC1) 3 1N4148 small signal diode (D1,D2,D3) 1 5.6V 400mW zener diode 1 100mF 16V PC electrolytic capacitor 1 100nF MKT polyester or monolithic (code 104 or 100n) Resistors (0.25W, 1%) 1 10kW 1 3.9kW 3 1kW 2 680W Fig.2: this is the full-size etching pattern for the PC board. Check the board for etching defects before installing the parts. February 2007  39 Teac GF350 Turntable/CD Burner For those people who don’t want to bother with a separate turntable, a computer and software, Teac has produced a single box solution for the chore of dubbing vinyl records to CDs. By BARRIE SMITH T EAC CALLS ITS NEW system a “Multi Music Player/CD Record­ er”, which I guess is par for the course in the 21st century. After all, who among the young set would know a turntable as anything but a rotating platter thing in a Chinese restaurant? But this Teac does have a record turntable that plays 331/3, 45 and 78 RPM records albeit unfortunately all with the one stylus! It also has a fairly decent AM/FM radio and an internal CD burner that accepts CD-R/RW blanks as well as replaying pre-recorded CDs. The whole shebang is attractively packaged into a desktop cabinet made of real wood … well, MDF actually. The styling is retro black, including the car radio-like front control panel, which has an attractively lit fascia with knobs! It displays the radio station frequency setting, current status (Phono, AM, FM, etc) and recording level. Unfortunately, the all-black colour has flowed into the top mounted turntable/pickup arm section, so re40  Silicon Chip cord playing is quite an effort in low light. A small lamp would have been a nice touch here. If you have become immersed, as I have recently, in dubbing those old records onto CD, this could well be your saviour, liberating you from the PC as well as the tangles with software, letting you shift the task over to a more user-friendly domestic appliance that would look at home in the average living room. In use The GF350 has been well thought out and its functions easily understood. If you want to dub an LP, you turn on the power, place a disc on the turntable, then load a blank CD into the tray. You then select Phono, lower the stylus onto the record, press the Record button and a display of the audio level appears. You set the recording level via the bargraph display. Next, reset the stylus onto the leadin grooves of the LP and let her go, then tap the Forward button and the recording to CD task begins. But an LP may last only 20-25 minutes per side, while a CD can run to 80 minutes. The Teac GF350 copes with this with the Pause button, allowing you to halt the CD burning while you flip the record over or replace it with another disc, allowing you to completely fill a CD. It’s even possible to separate and identify the tracks on the final CD. These you can insert manually while the dubbing is in progress or you can set up an auto task, allowing the unit to insert a track division when the replay level drops below -20dB, -30dB or -40dB for more than two seconds. However I believe that few of us will baby-sit an LP to CD dub just to drop in place markers and for the record, I had little luck with the auto ID mode either. I sometimes ended up with 18 tracks from a 7-track LP! I think the dynamic range of LP recordings is such that an auto identifying routine will never work. I have found that this is siliconchip.com.au also the case with otherwise “clever” software that handles the same task on a computer. Dubbing finished, you have to finalise the CD with a Table of Contents on the disc, otherwise it will not play on a domestic CD player. I had success with my very first LP-to-CD copying effort, using a CD-R blank but had no luck with any of my CD-RW blanks. Teac recommends the use of “Digital Audio” blanks: I found that CD-Rs could be used but it may be the reason why the CD-RWs would not work. There is an auxiliary input at the unit’s rear, so you can dub from an outboard CD player, cassette deck or even from a VCR. Oddly, there is no provision for you to make a CD copy of a radio broadcast, even though the quality of the unit’s AM/FM section is quite acceptable. Comment The Teac GF350 is a unique product and for what it attempts to do, it succeeds. In terms of audio reproduction, you can’t expect too much from a pair of 70mm speakers in a lightlyconstructed wooden cabinet. There is virtually no bass and the physical speaker separation is only 35cm, so the stereo listening sweet spot is an unrealistic 20cm from the front of the unit! The turntable is lightweight, as is the pickup arm, so my advice is to place it on a sturdy cabinet, isolated from footsteps in the room. There is no adjustable counterweight for the tonearm, so there is no provision for the stylus tracking weight to be adjusted, nor is there an adjustment for the anti-skating setting be fine-tuned. Worse, the cartridge is a ceramic unit, so reproduction is far from 21st century standard. And given that it is ceramic cartridge, you would think that Teac might have fitted it with a turnover stylus so that you could play 78 RPM records correctly. (Editor’s note: this is a throwback to the old portable record players of the 1960s. These units always had a restricted bass response to avoid the acoustic feedback from speakers to turntable that would otherwise result. The turntable and ceramic cartridge will also give poor reproduction compared to a good quality turntable, balanced tonearm and magnetic cartridge with the correct stylus.) Aside from the mode which idensiliconchip.com.au The Teac GF350’s smart looking, car radio-like control panel has an attractively lit fascia – and knobs! Among other things, it displays radio station frequency setting, the current status (Phono, AM, FM, etc) and recording level. tifies tracks for burning a CD from a record, there is little else to please the audiophile: no method to de-click noisy records; no way to precisely cue in the start of a track when dubbing. It is also highly probable that dubbing to CD from a quality external turntable and magnetic cartridge with preamplifier pickup arm would give a superior result than using the unit’s own player. It’s a pity the unit has no stereo output so you could hook it into your hifi to replay the golden oldies on a decent set of speakers. In spite of these cautions, let’s hope Teac takes the idea further and introduces some features in a future model to make the LP/78 copying task an easier and more elegant one: a better quality turntable and cartridge as well as a de-clicker built into the firmware would be a good start. Vinyl records, it seems, just won’t die! In spite of the above criticisms, the Teac GF350 is presently the only turntable/CD burner available. For many people it will no doubt give an acceptable result, allowing them to play 33s, 45s and 78s and make CD SC copies as well. Specifications: Teac GF350 • • • • • • • • • • Amplifier: 2 x 3.5 watts. Frequency response: 60Hz to 20kHz. Amplifier/tuner section: AM/FM stereo tuner. Record turntable/pickup: 33-1/3, 45, 78 RPM. DC servo motor, belt drive with ceramic cartridge. CD recorder: drawer type. CD-R/CD-RW. Speakers: 2 x 70mm, 4 ohms. In/outputs: headphone output, stereo RCA inputs. Accessories: manual, remote control and 2AA batteries, stereo RCA leads, 45 RPM adaptor. Price: $599 including GST. Distributor: Teac Australia 03 8336 650 or www.teac.com.au February 2007  41 Jaycar gets into wireless microphones W ith the possible exception of TV reception hardware, Jaycar Electronics have never been really big in radio frequency (RF) spectrum equipment. However, their first foray into radio (wireless) microphones is certain to set the proverbial feline amongst the grey winged creatures . . . The first thing we noticed about the new “Digitech” Wireless Microphone range from Jaycar was the prices. “Surely there is some mistake,” we thought. “A complete wireless mic system for not much more than others charge for the microphone alone?” No, Jaycar assured us. The prices were correct. “So are they toys?” we asked? (Yes, we’ve seen some of the junk being flogged on eBay and at the markets). “Most definitely not – they’re pro- fessional UHF systems. Would you like to have a look at one?” So it was that a day or so later not one but two of the three Digitech wireless microphone systems arrived at SILICON CHIP (the missing one was already out of stock!). Here’s what’s in the range: At the lower end, for want of a better word, is the AM4078 two microphone system. This is not a diversity system (see separate panel) – each microphone effectively has its own receiver. Claimed range is 60m – a figure which we were easily able to confirm during a field test. These units operate on the 740865MHz UHF band. Some of this band is occupied by band V TV (TV channels 59-69) but with 16 channels to choose from, there should be no problems finding an empty slot. The most important part of the equation, the price, we’ve left to last: it’s a very pleasant surprise at $199.00! Remember, this includes the two handheld mics (with batteries!), a plugpack adaptor (it operates on 14V DC) and a 1-metre 6.5mm to 6.5mm lead. The output to your amplifier can be separate (ie, one line per mic) or mixed to a single line out, while mic levels are individually adjustable. Audio quality sounds very natural (we’re not sure what the mic insert is – we didn’t have the heart to disassemble it). Receiver dimensions are 210 x 170 x 42mm. This type of system would be ideal for hall, club and church use. Middle of the range is a slightly more “upmarket” model, the AM4077. It too is a 16-channel system but this time features full diversity. “Hands-on” review by ROSS TESTER 42  Silicon Chip siliconchip.com.au However, it suits (and has supplied) just one microphone. Speaking of what is supplied, this system comes in a professional-style aluminium road case, so is obviously intended for professional applications. The LCD panel on the front of the receiver also gives you the received signal level in dB, making it very easy to find signal holes before they find you (in the middle of a performance or speech, for example!). The price of the AM-4077 is also another pleasant surprise at $249. If you’re looking for an all-round excellent performer, this one would be very hard to go past. Finally, the top-of-the-range AM4079 is virtually a combination of both the other systems. It’s a dual mic, dualdiversity, 32-frequency system (each mic can be selected to one of 16 channels) with a claimed range of 80-100m. As can be seen from our photo, there are four antennas (and each is removable for remote/powered antenna mounting). That’s because as a diversity system, there are two antennas for each channel and there are two channels. The twin LCD panels display channel selected, frequency and signal strength, so in a multiple-mic installation (eg, a theatre), channel conflicts between this and other brands can be avoided. Output is either via a separate balanced line for each channel, or via an unbalanced 6.5mm mono line with Jaycar’s “Digitech” AM4077 single channel diversity system comes complete with a quality microphone and an aluminium road case, as shown here. 16 user-selectable frequencies ensure there will be a vacant channel somewhere, UHF TV notwithstanding! On the opposite page is the top-ofthe-range AM4079 dual channel (ie two microphones) diversity system. the two channels signals mixed. The system includes two microphones with batteries, receiver unit in 19-inch rack-mount chassis, 14VDC plugpack and a 1-metre 6.5 mono plug to 6.5 mono plug lead. This system is also very attractively priced at $399 and there are generous discounts for multiple units. In use As we mentioned above, we gave both units a field test – more accurately, a “baptism of fire” using them for volunteer commentators at a major sports event. In the three areas most important to a commentator – range/dropouts, clarity and ease-of-use – the two Jaycar systems that we trialled performed as well as, or better than, we expected (the AM4079 easily spanned 150m). As we said before, audio quality was as good as any wireless mic system we have used in the past – and that includes some very expensive brands! If we can make one criticism, it is in the inclusion of 6.5mm audio cables. There is little point. XLR output sockets are provided on the receivers and the vast majority of amplifiers and mixers use either XLR or RCA sockets, so a different lead (or adaptor) is required anyway. SC What is Diversity? Wireless microphones are right behind the eight-ball when it comes to operating conditions. For a start, they are “flea power” – just a few tens of milliwatts maximum – so their range is going to be severely curtailed anyway. Second, the antenna orientation is all important. As with any transmitting and receiving antennas, the wireless microphone (which contains the transmitting antenna) and the receiver antenna should be aligned in the same plane for maximum performance. They seldom are. It’s natural for users to hold the microphone at any angle other than vertical! Some years ago, Shure published a chart of losses as the angle between the antennas increased – and they were a real eye-opener. The moral of the story: keep the microphone as vertical as possible! Third, with rare exception these days, radio mics use UHF – up around the 800MHz area. Lots of things – human bodies included – absorb UHF radio signals, so dropouts can be a real problem. Slightly changing position, or even changing the way the microphone is held, can suddenly siliconchip.com.au result in a mute performer. And multipath (reflected signals) can also cause receivers real angst! One of the most widely-used ways to minimise the effects of these (and other!) problems is to use a diversity receiver system. In this, just about everything from the antenna to the receiver output is duplicated. A monitoring system (these days, probably microprocessor controlled) continuously samples the output from both receivers and automatically and seamlessly switches to the best reception. Even if the antennas are not the desired wavelength (or greater) apart, invariably at any given instant one will be pulling in more, or better quality, signal than the other. On the front panel of a diversity receiver there are usually two LEDs, one for each diversity channel, which turn on as that receiving channel is selected. You can see them switch back and forth as you move the microphone around. Usually, as far as the audio output is concerned, it is impossible to detect which receiver is in use or when they switch. Nor is there any difference in output level between diversity receivers. February 2007  43 SERVICEMAN'S LOG Customers & their strange antics Recently, at a pre-Christmas dinner with some colleagues, we got to talking about some of the strange (and sometimes dumb) things customers get up to. You won’t believe some of these stories. Every so often, and even more so nowadays, one has to have a chuck-out to get rid of the sets that are dumped on you. A colleague recently hired a large skip (and believe me, that isn’t cheap) and loaded it to overflowing with sets that customers had either not picked up or had been dumped on him when the repair quote was rejected. The amazing thing was that by next morning, it was nearly half empty again. But even more incredible was the queue of people bringing the scrounged sets back in to be repaired or quoted for repair, each one of course being subject to a quote fee. My colleague explained the situation to each new customer but several still insisted that he go ahead. And because the job labels were still stuck to the backs of the sets, it was often just a case of looking up the job number on the computer to retrieve the details from the original estimate! In the end, he found this recycling extremely profitable – nearly enough to pay for the skip, in fact! And several sets were repaired that would otherwise have become landfill. The “faulty” cassette deck One old dear went to a garage sale many years ago where she spied a Items Covered This Month • • • Teac CTM519 TV set Teac PC-D800SR tuner/CD player JVC AV-25PX TV set (JK chassis) 44  Silicon Chip beautiful cassette deck for only $10. Delighted with her purchase, she took it home, plugged it and loaded it with her favourite music. The lights came on and the tape moved but no sound could be heard. “Oh well”, she thought, “I only paid $10 for it; I will take it in and get it repaired”. My colleague could see that it needed cleaning and lubricating, plus new belts and tyres, so he quoted accordingly. A week later, our little old lady picked the cassette deck up and took it home to try it out. Well, she was back again the very next day, still complaining that there was no sound. My colleague apologised and said he would check it out for her by the end of the day. He soon found that the unit was working perfectly and the sound was just great. What’s more, he could do nothing to make the unit misbehave. He told our heroine that he could find nothing wrong with it and advised her to take it home and try again. If there was any problem, he invited her to call and he would help her over the phone. Sure enough, she called a few hours later and said that there was still no sound. And by now, she was beginning to become rather agitated. My friend was quite perplexed by this. He was fairly sure there was nothing wrong with the unit, so what could she be doing wrong? He made various suggestions – such as turning up the volume control and pressing play, etc – but she assured him that she was doing all these things. Finally she brought it back in and my colleague connected it all up again. And as before, the sound was perfect. There was only one way to resolve this and so he invited madam to come in to the workshop and listen for herself. When she arrived, he turned the volume up for her and the workshop filled with sound. What happened next was quite unexpected. The little old lady pointed to the amplifier on which he had adjusted the volume and asked what it and the external loudspeaker were for. And she wanted to know why he was adjusting “that box” rather than the controls on the cassette deck. After a little confusion, the penny dropped. Our old dear thought that the cassette deck was complete with its own amplifier and speakers. She didn’t realise it was just a deck to be used as an accessory in a hifi system! Speaker pyrotechnics On another occasion, a young man came into the showroom to purchase some speakers. He spied a pair which had white cones and was rather taken by them, so he asked the salesman to give a demonstration. A brand new high-power amplifier had just arrived in the store, so the salesman connected it to the switching console, along with the loudspeakers. He then switched the amplifier on and turned the volume up. At first, everything sounded fantastic and the young man was really impressed by the quality. However, it was at this moment that there was a loud thud and the sound went dead. And then, right in front of their eyes, the voice coils in the loudspeakers began to glow a beautiful orange colour, this quickly changing to a red glow, in turn followed by smoke. “Wow”, he exclaimed, “I love it! Does it come in any other colours?” The amplifier had not only failed in both channels but the protection circuit had also failed. The result was a high DC output from each channel siliconchip.com.au which had fried the speakers. And to add insult to injury, the salesman’s last sighting of the young man was of him leaving for another store, to see if he could get some speakers which glowed a different colour! Reversed brain cells It’s not always the client that is lacking in the old brain power. Yours truly occasionally stuffs up too. The other day I had to repair an electronic distance measuring device. The repair was straightforward and when I had finished I fitted all the batteries for a final test. I then discovered that although the machine was trying to work, it was struggling and barely giving any sort of output. I dismantled it and checked all my work thoroughly again but could find nothing wrong except that the power supply was low. It took far too long before I realised I had actually fitted two of the batteries the wrong way around. Duh! The caring facade We live in a world where, superficially at least, it seems as though every­ one is extremely concerned for our safety and well being. Of course, this is all really a facade and the level of genuine concern is usually in inverse proportion to the rhetoric. For example, you enter one of our leading hardware stores and are met by one of the “team” with a jolly “how are you?”. That’s then followed by the now obligatory “have a nice day” as you are siliconchip.com.au leaving. Do they really care whether I have a nice day, an indifferent day or a rotten one? Want another example? Well, we’ve all seen the “For Your Safety” blurb that appears in the instruction manual for just about any piece equipment we buy these days. Call me a cynic if you like but I think it’s there mainly to save the manufacturer from litigation. Ever tried to get help for a software problem or other types of help over the phone? A common response from the software companies is that it is a third party’s responsibility for the problem – just uninstall, reformat or start again. I had a frustrating experience many years ago with a help-desk operator who worked for a cable TV company. In this particular case, I wanted to know the default RF output channel that the company’s cable box was set to, so that I would have some idea where to find it when tuning the TV. And the answer from the help-desk operator? “The box is not set to any channel – it’s on ALL channels and all you have to do is tune your TV into it.” I held my temper and tried rephrasing my question in several different ways but kept getting the same answer. Eventually, I said “well, how do I go about tuning my TV to your cable box?” “Sorry, can’t help you with that”, was the answer. “You will have to February 2007  45 Serviceman’s Log – continued get the TV manufacturer’s technician to show you how as they are all different”. In the end, I asked a colleague who immediately told me what the default channel was. He also told me how to change it to avoid co-channel interference, if necessary. French arrogance We had an arrogant Frenchman drop his Teac CTM519 TV into the workshop for repair. He told us it was dead and he wanted an immediate quote. There was no “s’il vous plait” either – this was an order. We looked at the set, gave him a quote, repaired the power supply and were happy to see the back of him when he picked the set up and left. However, a few weeks later, he returned, complaining that we hadn’t fixed his set properly and accusing us of incompetence. We asked what the problem was and were told that there was no colour on AV playback. Unfortunately, he no longer had the remote control or the instruction book. He insisted again that we fix it immediately and this time he wanted it done for free. We said that we would look into the problem and advise him – when we got the chance. We also explained that all we had done was repair the power supply and that our warranty covered this repair only. Furthermore, that was all he had paid for and we hadn’t been advised of any other symptoms when he first brought the set in. He really didn’t want to know about this and stalked out in a huff, leaving us with the set. Eventually, when we had a spare minute, we connected the set and tried it out. All TV channels came up in full colour but when the set was switched to AV1, there was no colour although the OSD displayed PAL as the selected colour system. Unfortunately, not having either the remote control or the instruction book meant that we were unable to immediately confirm whether it was a hardware or software problem. The AV signal went directly to the jungle IC inside the set, so it could have been the IC or one of its periph- eral components, or it could have been the EEPROM and/or the microprocessor IC. We didn’t have the correct remote control for this set but we did notice that the RC747 remote for the Teac CTM342HWQ controlled some of the functions. Each time you pressed the relevant button, it would cycle between each system – ie, NTSC1, NTSC2 and PAL. And when we cycled it back to PAL, the colour came on and no matter what we did, we couldn’t make it disappear again. This proved that there was nothing wrong with the set or the repair we had done on it. Rather, it showed the customer to be not only arrogant but stupid as well, as he had continued to abuse us over the phone and was even threatening to call the police because “we were ripping him off”. As it turned out, it was his own incompetence that had caused the problem. He sure didn’t say much when he picked the set up, although he could have at least tried an “excusezmois” or a “pardon monsieur”, or even a “je regrette” – not that we really expected it! The spooky Teac A good friend of mine purchased a Another Warranty Story: The Hard Disk Drive With Green Paint The September 2006 issue’s Serviceman’s warranty sagas prompted me to share one of my own. I used to be “Technical Manager” for a PC distribution group. We dealt mainly with large corporate customers. In the mid-1980s most PCs would be lucky if they had a 20MB hard drive, so external large capacity devices (up to a staggering 140MB) were popular for early “servers”. One well-known maker of these devices often combined them with tape drives (which no-one used) and the high-priced units (often two or three times the cost of the PC) went to the biggest companies in the country. Unfortunately, they were also supremely unreliable. To cut a short story long, one Monday morning, one of my wellknown customers arrived at my office with a box containing said drive which appeared to have exploded. Furthermore, it had patches 46  Silicon Chip of bright green paint on it. The story went that they were moving equipment in the office over the weekend and a junior was delicately carrying the unit from one side of the office to it’s new location. It seems that he caught his foot on the fixed cable coming out of the unit and tripped. The drive flew several metres across the office bounced off a desk and hit an outside window. The window shattered (these units weighed 6 – 8kg) and the whole device fell six storeys to the carpark below, where it landed on a Datsun. My first comment was “I bet it was a green Datsun”. Apparently it was. Unfortunately there was no way we could help them under warranty, since they freely admitted that the unit was not being carried in its protective packaging. Perhaps their insurance company might be able to assist? Then I re-checked the device. The fixed cable would be around 20cm long and was still perfectly intact (about the only thing that was I should add) The customer eventually confessed that this unit had given one too many “device not ready” errors and he’d thrown it across the room. The window and height above street level had been a severe miscalculation on his part. Chris Moran, via email. Comment: we feel sympathy for the guilty party. One of the SILICON CHIP staff members, who shall remain nameless, once threw a printer down the stairs when it misbehaved once too often. There was no chance of repair – it disintegrated into (seemingly) thousands of bits. It gave him great satisfaction sweeping it up because he knew it would give him no more irritation. siliconchip.com.au Teac PC-D800SR Tuner/CD Player which worked fine for years. But then, one day, the CD motor stopped turning and the player started making a loud “clicking” noise. He asked me to have a look and after I removed the lower shell, it didn’t take long to find the cause. The sled assembly was jammed and the clicking noise was caused by the motor jumping a gear tooth every so often. But what was really strange was that the sled assembly was jammed against a fixed electro on the PC board. This electro was normally bent out of the way but somehow this one had got bent the wrong way and was now hitting the sled. The owner assured me that no-one else had ever been inside the machine. So who or what had caused the capacitor to move? Spooky . . . One man’s burden A rather haughty “lady” brought in an old amplifier with one channel out of action. The fault turned out to be quite straightforward and was due simply to a faulty (noisy) balance control. We replaced it and soak tested the amplifier before returning it to the customer. A week later, the woman phoned up to say the amplifier sounded terrible and had “never been so bad”. And she was none too polite about it and didn’t hold back on the bad language either. We naturally apologised and tried to explain that it was fine when we checked it after the repair. We also told her that she was more than welcome to bring it back and we would check it out again for her at no cost. So she brought it back and we connected it up for her and demonstrated it. She still complained that it used to have a lot more bass, so we turned the bass up and the treble down. Whereupon she really threw a hissy fit. “Why did you move those controls?”, she fumed. “You have ruined it by adjusting them! You had absolutely no right to touch those controls”! And on and on and on . . . When she calmed down, we did our best to explain that in order to service the unit, they had to be adjusted. After all, they were “consumer” controls and it was up to the consumer to set the bass and treble controls to their liking. siliconchip.com.au February 2007  47 Serviceman’s Log – continued But it was no good and she continued to rant and rave. Finally, she picked up the amplifier and walked out, warning us that we would be hearing from her husband. We did, the very next day, but far from giving us a rocketing, he humbly apologised for her rude behaviour, intimating severe oestrogen-fuelled psychological problems! Furthermore, he went on, we were not the only people he was having to phone that day! Unfortunately, we can’t fix faulty customers. A bizarre story Finally, here is another slightly bizarre story. A JVC AV-25PX TV (JK chassis) came in under warranty five years ago with a picture tube problem. This particular set was manufactured in 2000 and there was an intermittent heatercathode short inside the green gun. The 60cm set was considered a write-off and so the customer was given a new TV. We kept his old set as a possible source of spare parts and it remained undisturbed in a corner of our workshop for five years. Recently, however, I wanted to demonstrate my old picture tube rejuvenator and tester and so this set was chosen as the guinea pig. After a few blasts from my machine, the picture tube was as good as new, the set now giving a consistently good clear picture with perfect greyscale, purity and convergence. However, the colours were incorrect, as though the incorrect TV colour system had been selected. However, this wasn’t the case as the correct CCIR B/G PAL D had been selected and there were no Hanover blinds. Furthermore, the OSD (on-screen display) menus all had the correct colours and a monitor connected to the output of the TV was also giving the correct colours. I quickly isolated the problem to be somewhere around IC251 (CXA2039M-X), a 24-pin surface-mounted IC costing over $60. In fact, by running my fingers over the IC pins, I could get the set to display the correct colours. But that was as far as I could go, because no-one could justify the extra cost of repairing this television even though it was otherwise in mint condition. The cost of replacing this IC – if indeed it did fix the fault – could not be recovered from the sale of this set in today’s market. So the set remains on death row as SC a donor for any similar set. Looking for real performance? Completely NEW projects – the result of two years research & development 160 PAGES • Learn how engine management systems work 23 CHAPTE • Build projects to control nitrous, fuel injection and turbo boost systems RS • Switch devices on and off on the basis of signal frequency, temperature and voltage • Build test instruments to check fuel injector duty cycle, fuel mixtures and brake & temperature Mail order prices: Aust. $A22.50 (incl. GST & P&P); Overseas $A26.00 via airmail. Order by phoning (02) 9939 3295 & quoting your credit card number; or fax the details to (02) 9939 2648; or mail your order with cheque or credit card details to Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. I SBN 09585 2294 9 78095 8 5229 From the publ ishe rs of Intelligent turbo timer -4 46 $19.80 (inc GST) NZ $22.00 (inc GST) 48  Silicon Chip TURBO BO OST & nitrous fuel con trollers How engin e management works siliconchip.com.au 2 Channel USB Oscilloscope Using the Plug 'n Play USB technology and providing full optical isolation from the computer, this oscilloscope is easy to setup and use, as well as providing protection for the computer. The software (developed in Europe) is a fully featured chart recorder, function generator, logic generator, logic analyser, and spectrum analyser all in one easy to use package. Supplied with interface module, software and probe. Cat. QC-1930 00 $ 299. Vernier Caliper - Tradesman Tough This carbon composite digital caliper is ideal for use where the cost of our precision stainless steel tool is not justified. The digital display is calibrated in imperial and metric units and a corresponding vernier scale is etched onto the caliper slide. Excellent value for money and tradesman tough. SUPER PRICE! Cat. TD-2081 95 $ 19. Fuel Cut Out Defeater Ref: Silicon Chip February 2007 Many factory turbo fitted cards have a limit to which the boost level can reach before a 'fuel cut' is activated by the vehicles ECU. This simple kit enables you to eliminate this factory fuel cut and go beyond the typical 15-17psi factory boost limit. The kit intercepts the MAP sensor signal and trims the signal voltage cutting the fuel supply. Kit supplied with PCB and all electronic componemts. Cat. KC-5439 Note: Prototype 95 $ 19. shown Combine the KC-5439 Fuel Cut Defender with the KC-5438 Simple Variable Boost Control kit to get the best dollar per kilowatt performance increase on the market! Simple Variable Boost Controller Designed for any turbocharged engine that uses an electronic solenoid to control boost levels via the ECU. This kit intercepts that signal and stretches it so that the signal to the solenoid has a larger duty cycle - that means more boost thus more power! Kit supplied with PCB and all electronic components. Note: a turbo boost gauge must be fitted to ensure boost levels aren't increased to a point that will destroy your engine. Cat. KC-5438 Note: 95 $ Prototype 19. shown Weather Stations Never before has the forecasting and viewing of local weather been this easy! XC-0292 This outdoor light is made from marine-grade, rustresistant stainless steel and is battery powered. Its 25mm clamping jaw and 480mm gooseneck will allow it to be position on a table, fence or BBQ. • Requires 4 x AA batteries (not included) • Spare 4W fluorescent Cat. SL-2806 tube available 95 $ separately. SL-2807 29. 32 Channel UHF Wireless Microphone with Diversity Receiver SAVE $50 XC-0291 These advanced, computer interface weather stations monitor the indoor environment and receive data from the outdoor sensors. The data is then displayed on the LCD screen and can be uploaded to a computer. The outdoor sensors are simple to install and will transmit up to 60 Measure: indoor/outdoor temperature and humidity, rainfall, metres to the wind speed, wind direction, chill indoor unit. factor and dew point Two models available: XC-0291 Weather station Cat. XC-0291 with PC interface 00 $ Was $399.00 XC-0292 Weather station with Cat. XC-0292 PC interface and touch screen 00 $ Was $499.00 349. 449. Indoor Weather Station It can be either wall or desk mounted and features a large LCD with full clock and calendar functions, dual in/out temperature readings, humidity, barometric pressure and weather trend. Supplied with an external transmitter to measure outdoor temperature, pressure and humidity. • Batteries included • Size: 110(W) x 110(H) Cat. XC-0335 95 $ x 37(D)mm 49. Weather Station with Clock, Wireless Sensors, and Doorbell The system consists of two wireless outdoor sensors, a wireless doorbell and an indoor receiver. The device will measure indoor and two outdoor temperatures, humidity, barometric change as well as the respective maximum / minimum temperatures and humidity. The indoor receiver has a large LCD which shows full clock, calendar and weather functions well as an audio and visual annunciation when the doorbell is pressed. Display is 260mm high. Cat. XC-0336 95 $ 99. FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 Stainless Steel Flexible BBQ Lamp INTERNET> www.jaycar.com.au Suitable for professional and stage use, this UHF wireless microphone system features 16 userselectable channels on each microphone input to provide interference-free transmission. It also has phase locked loop (PLL) circuitry for frequency stability. Two microphones Diversity included! Type! Cat. AM-4079 00 $ 399. Solar Powered Garage LED light Ideal for garages, gazebos and greenhouses, the 360° adjustable solar panel will allow for custom positioning. It's waterproof, features a cord-switch to operate, and is simple to install. Pack includes solar panel and mounting bracket, 2.4m cable and rechargeable enclosed Ni-Cd battery. Cat. SL-2715 95 $ Right Angle Ratchet Driver with 9 Bits A handy right-angle ratchet driver for hard-to-reach places. It comes with 9 bits, and can take any standard 1/4" hex driver bit. 39. Cat. TD-2013 95 $ 7. Digital Multimeter Kit Learn everything there is to know about component recognition and basic electronics with this comprehensive kit. From test leads to solder, everything you need for the An outstanding construction of this meter educational kit! is included. All you'll need is a soldering iron! • Meter dimensions: 67(W) x 123(H) x 25(D)mm Cat. KG-9250 95 $ 19. 1 8-in-1 Universal Remote Control with LCD SAVE $10 PA Solutions Operate up to 8 different devices at once including TVs, DVDs, VCRs, air conditioning units & more. This remote comes pre-programmed for easy set up, quick search and works with over 100 brands of electrical devices. Was $39.95 • Batteries included Cat. AR-1725 • Measures 55(W) x 95 $ 210(H) x 30(D)mm 5 Watt Megaphone For clear effective voice amplification, get your message across with this 5 watt megaphone. Works effectively up to a distance of 200m. • Requires 8 x AA batteries (not included) • Weight: 1 kg • Dimensions: 195(W) x 320(L)mm 29. 10W version also available AM-4058 Low Cost Stereo Amplifier This 18W per channel transistor amplifier is protected from accidental speaker wiring shorts and has a front panel microphone input, bass and Cat. AA-0472 treble controls as well as a 95 $ master volume control. Cat. AM-4056 00 $ 79. Dual Channel Wireless UHF Microphone 39. Visitor Door Chime Alarm with Counter USB Keychain Bible SAVE $5 Perfect for the shop or office. When passed it gives a pleasant 'Ding-Dong' alert and records the customer in it's digital tally count. Cat. LA-5009 • Effective for up to 5 metres 95 $ • Batteries not included Was $19.95 14. It features two separate channels, one for each microphone. Output is either via separate balanced XLR sockets, one for each channel, or via an unbalanced line with the two channels mixed. The system includes 2 microphones and batteries, receiver unit, 14VDC plugpack and one metre 6.5 mono plug to 6.5 mono Diversity plug lead. Type! Magic Wave FM Radio This futuristic radio is controlled by your hand movements. The sensor on the righthand side scans or changes the FM radio station and the left-hand sensor controls the volume. The face of the Cat. GH-1025 radio can also be set as a 95 $ colour-changing mood light. Cat. AM-4078 00 $ 199. 79. Wireless Audio Video Senders With a AV signal range of 60m (line of sight), transmit clear video and sound from sources such as you set-top box, TV, DVD or security cameras to anywhere in your home without the need for cables. 2.4GHz Wireless Audio and Video Sender It features phase-locked loop (PLL) electronic circuit that constantly adjusts, locking onto any input signal and avoiding any reception drift. Pack includes a transmitter, receiver, AV leads, power supplies and instruction manual. Cat. AR-1842 Additional receivers available 95 $ AR-1843 $44.95 69. Two Channel Input 2.4GHz Wireless Audio Video Sender SAVE $29.05 This unit supports two AV devices connected to the transmitter and allows you to switch between them. With this unit you can feed as many receivers as you like. Includes built-in IR remote control repeater, selector switch, AV leads, power supplies and instruction manual. Was $129.00 Note: This unit does not simultaneously broadcast two signals Cat. AR-1846 95 $ 99. Additional receivers AR-1847 $69.95 2 This tiny electronic bible plugs into your computer's USB port and contains the complete King James version of the Old and New Testaments in both English and Spanish. It also has a Cat. GE-4015 search function to help you 95 $ find your favourite verse. 39. 2 Channel Wireless Intercom 64. Electronic Photo Frame SAVE Plug in your data card and choose how $50 you want your photos displayed: multiple images in a slide show, a single image or thumbnails. You can also play a sound track for accompaniment, show video clips or print your photos on a compatible printer. The frame has a brushed silver-like finish and can be wall mounted. Remote control with battery and 12VDC plugpack included. • Holds as many pics as the Was $299.00 capacity of your data card Cat. QM-3759 • Dimensions: 238(L) x 184(H) $ 00 x 40(D)mm 249. Home Theatre Mounting Equipment Ceiling Mount Projector Bracket A heavy-duty bracket with swivel and tilt adjustment. • Maximum weight: 20kg • Mounting system: Universal top mount • Vertical arm Cat. CW-2817 measures: 95 $ 110mm 69. Projector not included Our amplifiers have taken pole position for two consecutive years in Car Stereo Australia’s Product of the Year Awards. We have an amp to suit every application. See our website for all the great features! 2 x 80WRMS Response Car Amp 2 x 80WRMS <at> 4 ohms 2 x 100WRMS <at> 2 ohms 1 x 200WRMS <at> 4 ohms This bracket does not affix to the top of the projector like many models but provides a secure platform for ANY projector with a width of 34cm to 47cm and a weight of not more than 15kgs. • Vertical arm measures: 500mm adjustable to 700mm Cat. CW-2818 95 $ 99. TV Wall Bracket It revolves through 90° and tilts 15° and can handle weight up to 30kgs or less. Shelf width is 300mm, depth 280mm. Cat. CW-2810 Was 95 $ $42.95 Car Amplifiers Car Amplifiers Heavy Duty Ceiling Projector Mount 32. SAVE Plugs into a 240V power point and sends $10 audio signals to another room. Both units need to be on the same channel to communicate. The intercom has a built-in monitor function and additional units can be added to the system to provide a Cat. AI-5500 multi-point intercom system. 95 $ • Sold as a pair Was $74.95 Cat. AA-0420 95 $ 169. Response Car Amp Class D 800WRMS 1 x 400WRMS <at> 4 ohms 1 x 700WRMS <at> 2 ohms 1 x 820WRMS <at> 1ohm Cat. AA-0428 00 $ 399. 4x100WRMS Full Range Car Amplifier • 4 x 100WRMS <at> 4ohms • 4 x 150WRMS <at> 2ohms • 2 x 300 WRMS <at> 4ohms "A recommended buy - thanks to its price, efficiency and useful preamp functions" - Car Stereo Australia Magazine Cat. AA-0425 00 $ 399. 1500WRMS Class D Amplifier SAVE $10 • 1 x 800WRMS <at> 4 ohms • 1 x 1000WRMS <at> 2 ohms • 1 x 1500WRMS <at> 1 ohm "The Class D 1500W amp with its great build, mega grunt, awesome preamp and excellent connectivity, forged further ahead than all others nominated" - Car Stereo Australia Magazine SUB-WOOFER AMPLIFIER JAYCAR AA-0429 Cat. AA-0429 00 $ 699. FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Mains Timer with LCD A switching contact rated at 30 amps! Featuring 8 on/off programmes across 16 combinations of days or blocks of days for unrivalled flexibility. The unit also has a one touch 'summertime' button to convert from daylight savings time when it ends. for Great , security s ic n o h p hydro ng and muc lighti more Cat. MS-6110 95 $ 29. 12 Volt 1.26 Watt Solar Battery Charger Ideal for charging sealed lead acid batteries, this 12V 1.26 watt solar panel is tough enough to be walked on and can be mounted on a flat surface or on its brackets so it can be moved to follow the sun. • Current (max): 70mA • Panel size: 159 x 175 x Cat. ZM-9016 17mm 95 $ • Size: 159 x 175 x 17mm Replace and Save Provides a stable current with a regulated output voltage which is adjustable from 0 to 30VDC. Output current is adjustable from 0 to 3 amps. The unit features an uncluttered control panel with LCD, voltage and current adjustment knobs. See our website for full Cat. MP-3086 specifications. 00 $ SUB C 1800mAh Our ultra-high drain Ni-Cd battery is designed and manufactured for high capacity and high current performance. Rated at 1800mAh, these cells are ideal for power tool replacement packs. r Drill Pack SUB Cs Needed See ouool 12VDC 10 Cat. SB-2468 Powertontrol C 95ea $ 14VDC 12 Charge page 8 4 Pack of Rechargeable Kit on 18VDC 15 Modern digital devices require high current, high drain iPod Replacement Batteries performance cells. Buy in Once your iPod starts to fade it is probably the packs of 4 and save! internal rechargeable battery. We can supply 1st to 4th generation iPod and SB-1735 2400mAh iPod mini battery replacements. AA $15.95 Includes instructions, and tools SB-1737 2000mAh to safely open your iPod. AA $13.95 SB-2570 1st / 2nd generation SB-1739 900mAh SB-2572 3rd generation All Types (ea) AAA $11.95 SB-2574 4th generation 95 $ SB-2576 Mini 199. 6. Key Fob Learning Remote Controls Dual Battery Isolator Cat. MB-3670 95 $ 89. These learning remote controls can program up to 4 different frequencies. They can be programmed for the car alarm, central locking, garage roller doors or even some home alarms. • Supplied with full instructions and battery • Not suitable for code hopping alarms LA-8990: Frequency range 290MHz - 410MHz Both Types (ea) 95 $ LA-8992: Frequency range 250MHz- 450MHZ 39. Power - when you need it Inverters 12VDC to 230VAC Inverters Inverters are available from 150W to a massive 1500W. All have a LED power indicator, electrical isolation between the battery and secondary voltages for safety, and the higher power inverters feature fan assisted cooling. 24V inverters also available. Power (W) Surge (W) 150 450 300 1000 400 1200 600 1500 800 2000 1000 2500 1500 3500 Price $48.95 $99.95 $159.95 $249.95 $299.95 $399.95 $599.95 Can Sized 150W 12VDC Inverter Utilising the existing drink holders in cars, this inverter is held in place and doesn't need any modifications to vehicles. Featuring a 150W power output, this unit has the capability to run a laptop computer or other equipment. Cat. MI-5121 95 $ * Colour may vary. 49. If has a built-in 17Ah battery to jump-start your car, a cigarette lighter outlet for use as a auxiliary power source, test button with voltmeter and a work light. Recharging this power pack is via the supplied plugpack. • Extra long 850mm heavy-duty cables • Dimensions: 330(W) x 380(H) Cat. MB-3596 95 $ x 100(D)mm 12V Notebook Power Supplies They have a 12 to 13.8V input voltage, feature a recessed voltage selector to eliminate accidental changes to the selected voltage, high efficiency, low power consumption, LED power indicator and are supplied with 7 output connectors for all major laptop brands (see website or in-store for listing). • Terminates to a fused 10 amp automotive cigarette lighter socket Cat. MP-3463 MP-3463: 15/16/18/19/20/ 95 $ 22/24VDC <at> 3.5amps MP-3467: 15/16/18/19/20VDC Cat. MP-3467 <at> 6 amps 95 $ 22/24VDC <at> 5 amps SAVE Was $69.95 39. 49. $20 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au 0-260VAC Variable Autotransformer (Variac) 500VA It will enable the AC input to a mains powered appliance to be varied from 0 to full line voltage (or greater). Encased in a heavyduty steel housing, it has an outputvoltage meter, mains lead and is supplied with a fuse. See website or catalogue for full specifications. Was $199.00 Cat. MP-3080 00 $ 179. SAVE $20 Outdoor Gadgets Rechargeable LED Work Light High-End Jump Starter Power Pack with Light 79. Cat No MI-5102 MI-5104 MI-5106 MI-5108 MI-5110 MI-5112 MI-5114 Ni-MH Batteries 29. 39. This unit will direct alternator charge current to your main and auxiliary battery when the engine is running. When you are stationary and drawing battery power (for fridges etc), the unit will isolate one battery before both SAVE batteries go flat. $10 Was $99.95 Regulated Variable Lab Power Supply It has a strong magnetic mount, twisting handle and hanging hook. This robust unit has two lighting options, 1W LED for use as a torch, 30 LEDs for use as a lamp and is supplied with mains and car chargers. • Measures at 360 x 45 x 55mm Cat. ST-3024 95 $ 39. Magic Ratchet Driver with 6 Bits Takes 1/4" hex bits and features a shaft that extends from 60 to 165mm. It can be locked in at lengths of 80, 100, 120 and 140mm and releases at the push of a button. • Includes 2 each slotted, Phillips and Posidriv bits • Dimensions: 220mm closed, 320mm extended Cat. TD-2057 95 $ 14. Foldable Binoculars & 6 in 1 Survival Tool Contained within its ABS housing is a compass, mirror, retractable 4 x binoculars, LED torch, and magnifying glass attached to a key chain. Use the mirror to attract attention in case of an emergency, the LED torch can be used as an reading lamp and the magnifier can Cat. GH-1114 95 $ assist in building a fire if needed. 9. 3 Wireless 6 Zone Remote Control Alarm Kit Control up to 6 zones with 2 sensors in each zone. Monitors the system status by receiving signals from the sensors at one hour intervals. Includes control panel with keypad, remote control, PIR sensor and a reed switch. Wireless installation - ideal for tenants. Batteries and power supply included. Additional PIRs, reed switches and remote controls are available and sold separately. See website for full Cat. LA-5135 00 $ features and specifications. 199. 2.4GHz Colour Mini Wireless Camera Kit The camera transmits audio and video up to 100m (line of sight) to the receiver. It can be powered by a plugpack or by its in-built rechargeable battery, and has 4 transmission channels to minimise interference. The receiver has composite video out and is powered by the supplied plugpack, Kit includes camera with bracket, power supplies, AV lead and receiver unit. • Camera size 67(L) x 22(W) mm Cat. QC-3569 • Receiver unit size 78(L) x 68(W) x 00 $ 16(D)mm 199. 2.4GHz Transmitter for Video Cameras This compact transmitter simply plugs in-line with an ordinary security camera and turns it into a wireless unit which can broadcast on one of four Cat. QC-3594 standard channels. 95 $ Was $69.95 SAVE $10 59. Solar Powered LED Lighting When darkness falls, these spotlights switch on automatically. They have high-intensity LEDs and a built-in solar panel to charge the internal batteries during the day. Three styles are available including constant illumination and a PIR operated motion-sensing model. Stainless Steel Solar LED Spotlight • 11 LEDs • Illumination duration: 10 hours Cat. SL-2714 95 $ 49. Solar LED Spotlight • 30 LEDs • Illumination duration: 10 hours • Polycrystalline solar panel Cat. SL-2716 00 $ 129. Solar LED Spotlight with PIR Motion Sensor • 30 LEDs • Illumination duration: 20, 40, or 90 sec. PIR controlled • PIR Sensing range: 15 metres Cat. SL-2718 00 $ 99. 4 DVR and Camera Kit DVR with Dome and Weatherproof Colour Cameras The DVR is fitted with a 250GB hard drive, can accommodate up to 4 cameras with power derived from the DVR and will allow you to record BUY THE DEAL AND and view up SAVE! to 4 cameras simultaneously.This package includes the DVR with a dome and outdoor IR camera with bracket, mounting hardware, power supply, 14m camera connect cable, software, USB interface Cat. QV-3085 00 $ lead and user manual. 999. Colour Weatherproof IR Camera Replacement or additional camera for the DVR and camera kit QV-3085 (Shown Above) This 380 TV line camera features a 1/4' Sharp CCD sensor and is weatherproof. • Dimensions: 75(L) Cat. QC-3086 x 52(dia)mm 00 $ 199. Colour Mini Dome Camera Replacement or additional camera for the DVR and camera Kit QV3085 (Shown Above) The 380 TV line camera has a 1/4" Sharp CCD sensor and is intended for indoor use. Cat. QC-3087 • Dimensions: 86(dia) 00 $ x 60(H)mm 149. Colour CCD Variable Focal Length Camera This 380TV line camera features a Sony HDD CCD sensor, flicker reduction technology, auto iris and auto white balance, back light compensation and operates on 12VDC or 24VAC. • 160(L) x 52(W) x 48(D)mm The vast array of features include 250GB HDD, MPEG-4 compression for image clarity, motion detection, covert recording, alarm trigger recording, time/date stamp, image water marks and more! Connect the device to a network and utilise your recording system from anywhere with web access. The 16 channel unit also supports GPRS that will allow a mobile phone to control PTZ motion and to access images. See our website or catalogue for full specifications. Available in a 4 and 16 channel. 4 Channel QV-3071 Was $899.00 SAVE Cat. QV-3071 $100 00 $ 799. 16 Channel QV-3076 Cat. QV-3076 Was 00 $2399.00 $ 2299. SAVE $100 4 Channel DVR with Weatherproof Colour IR Cameras View and record 4 video channels at once. The 4 colour cameras have IR illuminators for night use and are weatherproof. Comes fitted with a 250GB HDD, but supports up to 400GB hard drives and the cameras are all powered from the DVR. The pack includes 4 colour IR cameras, power supply and all cables. See website for full specifications. Was $1299 Cat. QV-3070 00 $ SAVE $200 1099. 299. Vandal Resistant Colour CCD Dome Camera This 520TV line camera is made of extremely durable materials and will survive impacts that would destroy other cameras. Features a Cat. QC-3290 Sony HAD CCD sensor, 3 axis 00 $ movement (pan 180°, tilt 180° and rotate 170°) and operates from 12VDC. 299. Digital PCI Cards with MPEG 4 They incorporate high speed real time compression and digital motion detection, alarm event recording and logging, variable compression, and mixed frame rate recording. The surveillance images can be accessed remotely via a LAN, WAN or the Internet. Available in 4 and 8 channel: 4 Channel 8 Channel Cat. QV-3080 Cat. QV-3082 00 00 $ $ 249. 399. Surveillance February Security Clearance Huge Reductions on Multiplexing Digital Video Recorders Cat. QC-3518 00 $ 5.5" B&W Monitor with Camera & Dummy Camera Pack Consisting of a 5" B&W surveillance monitor, two cameras, and two dummy cameras, you can keep an eye on your premises. The real cameras simply plug in with their 10m lead, and the dummy cameras Cat. QC-3446 look identical. 00 $ Was $149.00 SAVE $20 129. Surveillance Camera with DV Capture A surveillance camera with an incorporated digital recorder. The 380TV line VGA camera has composite video out and can be either mains or battery powered. It has continuous or motion-detection record options and includes 64MB of flash memory. Cat. QV-3092 00 $ Mains power supply and all mounting hardware included. 349. Mini Portable Security Recorder With a built-in sensor just connect this unit to a standard camera with composite video and the unit will record audio and video to an SD card. The AV input/output sockets connect to an external monitor (not included) and the front panel of the unit has full playback functions. • 5VDC plugpack and AV cables included • Requires 2 x AA batteries for portable use SD card not included Cat. QV-3094 00 $ 399. FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Digital Voice Recorder with MP3 Player SAVE $20 This sleek digital voice recorder has it all! The batteries will last up to a massive 22hrs and the unit features ID3TAG technology, multi-language support and a large backlit LCD. The recorder also servers as an MP3/WMA player and USB storage device. • Required 2 x AAA batteries (included) • Earphones, lanyeard, software and Cat. XC-0256 USB interface cable supplied 95 $ Was $219.95 199. 12VDC & 240VAC Battery Charger with LCD The Short Circuits Learning System The Short Circuits learning system is a great way to learn electronics. It is fun, informative, and you build great projects along the way. Here are just three examples of projects in the Short Circuits series. FM Microphone Endless uses! This transmitter could be used as a baby room monitor, a wireless microphone or as a spy bug. It can be picked up on any FM radio. Kit includes PCB, electret microphone and Cat. KJ-8078 electronic components. 95 $ Features in Short Circuits #3. 9. Recharge up to 4pcs of AA or AAA Ni-Cd or Ni-MH batteries with this handy charger. With Delta V voltage detection, the batteries are charged to their optimal level. Charge state can be monitored on the integrated LCD that is backlit. Cat. MB-3543 • Supplied with mains 95 $ and car chargers What is that Cricket Noise? 49. Smart Dog USB Hub Radio A cute and byte-sized multi-function companion. Unclip his head from his body and he turns into a portable radio that you can take anywhere. Attach his head back and his body turns into a speaker and USB hub. • Length 110mm • Batteries not included Cat. XC-4844 95 $ 19. This fun project makes the distinct sound of a cricket when triggered by a hidden microphone. Hours of fun. PCB and all other electronics including microphone supplied. Cat. KJ-8224 Requires 9V battery. 95 $ Features in Short Circuits #2. 12. An elementary learning system, this pack includes the project book, plastic baseboard, spring connectors and all components needed to Cat. KJ-8502 complete 95 $ every project. 36. Make international phone calls at the cost of a local call. VoIP technology is a form of communication from internet calls to landline phones. This unit plugs straight into a spare USB port on your computer and has a hands-free function. It is compatible with Skype, MSN, Yahoo Messenger, Xten and Cat. XC-4966 more. * Please consult your 95 $ telephone provider for pricing. USB Missile Launcher 49. Connected to your USB port the software will allow you to navigate the missiles trajectory, pan 180°, tilt up to 45° and provide realistic sound effects. The missiles are made from soft foam so it's safe to use at home or in the office. • Not suitable for children. • Replacement missiles available Cat. GE-4072 95 $ GE-4073 $6.95 pkt 3 49. Binoculars with AM/FM Radio 179. 1000VA Uninterruptible Power Supply 34. Twin-Pack 38 Channel UHF Mini CB Radios This pack of 2 mini UHF CB communicators can keep you clearly in touch up to 3km. They feature electronic volume control, monitor functions and an integrated blue LED torch. Each unit requires 3 x AAA batteries (not included) Cat. DC-1005 See our full 95pr $ 49. INTERNET> www.jaycar.com.au Golf Cart Pen Holder This miniature golf caddy pen holder includes three pens in red, blue, and black which are cleverly shaped as real golf clubs. Cat. GH-1884 95 $ 19. Golf Ball Mouse and Mouse Pad With 8 x magnification and an AM/FM radio these binoculars are ideal in the grandstand or at the track. Lightweight, compact with waterproof casing and includes a belt hook, lens cloth and earphones. • Batteries not included Cat. GG-2127 95 $ • Measures 95(L) x 65(W) x 28(H)mm FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 All you need is water and sunshine. This palm-sized car has an on-board TIME Magazine's hydrogen storage tank, a fuel 2006 product of cell system connected to the car's the year! electric motor, and a hydrogen refueling system linking the car's storage tank to the solar-powered refueling station. Includes Hydrogen Cat. KT-2529 Fuel Cell! 95 $ For the Desktop 19. USB VoIP Phone with LCD and Hands Free Option H-Racer Hydrogen Car Kit with Solar Refueling Station Gadgets The razor is housed in a sturdy case that is easily removed to reveal the razor and a compact illuminated mirror. Great for planes, trains, and automobiles. • Cleaning brush and Cat. GH-1515 batteries included 95 $ • Dimensions: 62(W) x 103(H) x 25(D)mm 39. 9. 199. Travel Shaver It features a standard calculator with functions for financial calculations and connects to your laptop or workstation for use as an external numerical keypad. It's also a passive 3 Cat. XC-4846 95 $ port USB hub. Just plug this little beauty into your computer’s USB port, put the pencil into the hole for sharpening and voila! - the perfect point! Great for office and home use. Cat. GG-2269 • Flashing LED while in use 95 $ • Batteries not included • Unit measures 75(L) x 65(W) x 72(H)mm Protect your valuable computer system from power failures, preventing data loss or corruption. The included software can be set up to save your data and close down your computer automatically if the power fails. The UPS is supplied with two 12V 7Ah SLA batteries, USB interface cable and software. • 600VA UPS also available Cat. MP-5202 00 $ MP-5200 $129.00 Short Circuits 1 Project and Book PC Companions Solar Powered Calculator with 3 Port USB Hub USB Pencil Sharpener range of UHF CB radios in-store! The set comes with 3 miniature golf balls, a removable flag and a miniature putter for you to practice your skills in those office 'quiet' times. The mouse connects to your computer via the USB port and has a 1.5m lead for easy placement. Cat. XM-5129 95 $ 24. Miniature Golf Buggy with LCD Alarm Clock This miniature 1:18 scale golf buggy has a LCD screen as a windshield which has full clock functions with a calendar and temperature setting. • Includes battery and 2 sets of miniature golf clubs • Measures 140(L) x Cat. GH-1880 95 $ 75(W) x 100(H)mm 24. 5 Professional Cat IV Multimeter Probes 1200mm extra long leads, Cat 1V rated for safety, features a finger guard and can handle 20A of current. The probes are suitable for inserting into a standard Cat. WT-5338 4mm banana socket and 95 $ includes probe covers. 14. 3 in 1 Stud Detector with Laser Level This unit indicates proximity when you are near a stud via its large LCD and shows a target graphic when you're spot on. The unit also features voltage detection and a built-in laser level. • Battery included Cat. QP-2288 95 $ 49. 79. Test and Measure 10MHz Velleman Personal LCD Handheld Oscilloscope 299. Auto Current Tester Simply plugs into any standard blade type fuse holder and provides an easy-to-read LCD of the circuits performance. The unit will measure up to 48V max, current 20A. With 400mm cable length. • Supplied with 12V A23 type battery • Measures 86(L) x 37(W) x Cat. QP-2251 95 $ 28.5(D)mm 199. 29. 19. Includes just about every driver bit you could want. • Metric and Imperial sizes • Even has a 'Wing Nut' driver • Driver handle to suit Cat. TD-2038 95 $ TD-2032 $5.55 Inductance / Capacitance / Frequency DMM Ideal for audio enthusiasts designing their own crossovers. This meter features a large LCD and has auto power off. Supplied with holster, battery and temperature and test probes. 16. 1000V 7 Piece Screwdriver Set GS and VDE tested and approved. Soft rubber grip handles, with insulation right to the tip. See our extensive DMM range in-store CHECK THIS GREAT PRICE! Cat. TD-2022 95 $ Megohmmeter 19. Megohmmeters generate high voltage, low current signals for testing the breakdown strength of electrical insulation. Despite the low price, it still includes a rubber holster, test leads with alligator clips, 200M and 2000M ohm ranges and simple, one button, 'push Cat. QM-1492 to test' operation. 95 $ Resistance Wheel Convenient resistance selection. Select from 36 values from 5 ohms to 1M ohms. • Comes complete with leads and insulated crocodile clips. • Uses 0.25W resistors with Cat. RR-0700 5% tolerance 95 $ 99. Tool Kits The pistol grip on this driver gives you maximum control and allows your fingers to fall naturally on the forward/reverse control switch. It has an LED lamp, magnetic bit holder and a battery level indicator. Mains charger and 4 bits included. • Bit holder size: 6.35mm • Belt pouch now available Cat. TD-2498 95 $ TD-2499 $5.95 "The Casino" 100 pc Driver Bit Set 24. 18 Piece Pink Tool Kit The Velleman Personal Oscilloscope is ideal for hobbyists, students, service people, automotive applications & general development. SAVE Ask in store for full details. $50 Was $349.00 Cat. QC-1916 00 $ Cat. QP-2290 00 $ A excellent, accurate meter that is Cat II rated. It features diode, frequency and capacitance test, duty cycle, continuity, relative measurement and includes battery, probes and holster. SAVE Cat. QM-1535 Was $5 95 $ $29.95 39. This clever device will allow you to use an ordinary IDE or SATA disk drive on a USB-2 interface. The adaptor can be powered from the existing computer power supply or from the supplied mains adaptor. The adaptor has plug and play support for Windows ME, 2000, and XP. • Win98 supported via downloaded Cat. XC-4833 software 95 $ • Interface cables included Tests all common low voltage cabling systems found in today's automated homes such as Voice, Data, and Video Networks. Comes with remote unit. Autoranging DMM Cat. QM-1324 95 $ USB to IDE and SATA Hard Drive Adaptor VDV Multimedia Cable Tester Get a New Meter for the Job Cordless 4.8V Screwdriver 19. Bonus bandana, gloves & a 20 page DIY manual Includes: hammer, 2 x flat-bladed screwdrivers, 2 x Phillips SAVE screwdrivers, pliers, tape $10 measures, driver bit handle, extension bar, 2 x jewellers & tweezers. Supplied in a pink attaché metal case. Cat. TD-2068 • 338(W) x 84(H) 95 $ x 305(D)mm Was $59.95 Service Aids Desk Clamp Magnifier Lamp This is a high quality, all metal frame construction magnifier which features a 22 watt circular fluoro built inside the magnifier head. SAVE The magnifier itself is a 3 dioptre $10 lens. Total extended length 990mm. (Replacement fluoro Cat. QM-3525 tube QM-3523 $13.95) 00 $ Was $109.00 99. 49. Anti-Static Field Service Kit Computer Service Tool Kit Included in this service kit is an IC inserter/extractor, pearl catch, tweezers, 1/4" nutdriver, 3/16" nutdriver, double ended 10/15 TorxTM driver, parts tube for storage, #1 Phillips screwdriver, #0 Phillips screwdriver, 1/8" slotted screwdriver, 3/16 slotted screwdriver in a black zipper case. Cat. TD-2040 95 $ • Case measures 220 x 155 x 38mm 24. Tool Kit with Carry Case 23 Piece Tools included are, a driver bit handle, 2 x Phillips, Pozi, and slotted screwdriver bits, an adaptor for hex to a square drive, 10, 9, 8 and 7mm nut drivers, a telescopic Cat. TD-2063 pickup tool, tape measure, and a 95 $ set of long nose pliers with cutter. • Case:160 (L) x 115 (W) x 35 (H)mm 19. SAVE The mat folds out to reveal a work $10 area of approximately 600 x 600mm. At one end there are 2 pouches, a ground lead and wrist strap Cat. TH-1776 and at the other end there are 2 95 $ more pouches 200 x 300mm. Was $41.95 31. Dry Lubricant Spray - 175g This water displacing Teflon® lubricant is formulated to provide a dry, lubricating film that is perfect for use with electronic and mechanical assemblies etc. Cat. NA-1013 95 $ Bench Top Work Mat 13. This durable A3 size PVC cutting mat is just the thing to protect your workbench top. You can cut on it, solder and write on it. It is 3mm thick, 450 x 300mm. it is ruled with a centimetre spaced grid for easy referencing. Cat. HM-8100 95 $ 9. 6 FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Breadboard Mounted on a metal plate with rubber feet this breadboard features, 1680 tie points, 400 distribution holes, 1280 terminal holes and 3 banana terminals. Cat. PB-8816 • Board size: 130(W) 95 $ x178(H)mm Don't Work in the Dark 24W HID Rechargeable Torch 40. Breadboard Jumper Lead Kit This kit consists of a single core sturdy wire, which has been stripped on each end and bent at right angles. Cat. PB-8850 • 5 packs each of 14 95 $ different lengths 8. 36 Way Pluggable PCB Connectors Easy to use pluggable connector. Supplied as 36 way but can be easily separated into the number of contacts required. PCB mounting. Cat. HM-3270 HM-3270 - 36 Way Socket 95 $ HM-3272 - 36 Way Plug Cat. HM-3272 90 $ 14. 5. 4. 12. 28. Cat. PT-4420/22/24 175 Amp Cat. PT-4424 $ 95 37. Duratech Temperature Controlled Soldering Station It features a high quality SAVE ceramic heating element for $20 accurate temperature control, adjustable between 200° to 480°C. The soldering pencil is lightweight so it is comfortable for long periods. It is a great station, so check our website for details. Was $99.00 Cat. TS-1560 A Great Entry-Level 00 $ Soldering Station 79. Lead Free Soldering Station This is an industrial quality product. If your work requires compliance with 'Reduction of Hazardous Substance' (RoHS) directives, you must use lead free solder. This quality Japanese made station will go from cold to 350°C in six seconds! See our website for full specifications. Was $499.00 Cat. TS-1490 00 $ 449. Rechargeable 5M Candle Power Spotlight It has an integrated multi-position rubber grip, and a dual LED complimentary light. • Replacement globe Was $34.95 SL-3222 $8.95 • 6V SLA battery and Cat. ST-3303 95 $ chargers supplied Includes 3 LEDs and a fourphase switch that allows the user to select between using 1 or 3 LEDs. One minute's worth of winding will give you 30 minutes of light. Cat. ST-3337 95 $ Was $19.95 SAVE $5 14. They have side cable entry, solder termination and meaty finger grips on the side. The piggyback design allows for another banana plug to be inserted in the rear and being fully insulated, they're ideal where OH&S and safety are a concern. • 125VAC <at>10A • Cable entry - 4.5 mm dia. PP-0385 - Red PP-0386 - Black PP-0387 - Green PP-0388 - Blue PP-0389 - Yellow Price - Each $ 78 Panel mount sockets to suit Cat. PS-0420-24 $1.78ea 1. High Power Ultrasonic Cleaner Its massive 100W transducer produces millions of microscopic bubbles that are small enough to penetrate the most microscopic of crevices, cleaning them thoroughly. Use this cleaner for automotive injectors, jewellery, Cat. YH-5410 glasses, circuit boards and more. $ 00 The unit features a large display with real time count down and an easy to operate cleaning duration setting at 5 minute increments. 299. Non-Contact AC Voltage Tester with Torch About the size of a marking pen, this non-contact tester detects AC voltages from 100 - 600V. It can be used for detecting live mains in outlets, powerboards or insulated wiring. It also has an LED torch and a handy pocket clip. Cat. QP-2271 • Requires 2 x AA batteries (not 95 $ included) 18. Portasol Gas Soldering 50 Gas Soldering Iron It has a run time of around 30 minutes. Ignition is via the flint ignitor in the cap, and tip temperature is fixed, reaching an impressive 350°C. See website for spare tips. Cat. TS-1300 95 $ 29. Technic Gas Soldering Iron Soldering Pencils Soldering Starters Pack The kit includes our Duratech 25W 240V soldering iron, a quality metal stand with sponge, a length of solder and a roll of desolder braid. Cat. TS-1650 95 $ 19. It offers a run time of around 60 minutes, and the tip temperature is adjustable up to 450°C. See website for spare tips. Cat. TS-1305 95 $ Mini Gas Soldering Iron Super Pro Gas Soldering Tool Kit Great for soldering, cutting plastic, or heat shrinking plastic. Dimensions: 210(L) x 20(dia)mm 49. SAVE $10 It features an adjustable tip temperature up to 580°C and ignition is achieved by the internal piezo crystal mechanism. Run-time is around 2 hours on a 30 second refill. The protective end cap also acts as a safety gas shut off when replaced. The kit includes a quality storage case, cleaning sponge and tray, 2.4mm double flat tip, 4.8mm double flat tip, hot knife tip and a hot air deflector. Cat. TS-1328 • Replacement tips available 00 $ Was $139.00 129. FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 SAVE $5 Dynamo Wind-up LED Torch Soldering Stations SAVE $50 499. 29. High Current Anderson Type Power Connectors You'll find these 2 pole connectors in many 4WD applications, boating, automotive and other industries. Supplied individually with a pair of contacts and rated to 600V. Cat. PT-4405 30 Amp 50 Amp 120 Amp Cat. PT-4405 Cat. PT-4420 Cat. PT-4422 $ 50 $ 95 $ 95 Utilisng the same technology used in expensive European car headlights, no other torch is capable of such intensity in such a small More HID package. It can illuminate Torches in-store! up to a kilometre away. It has a burn time over a 100mins and is housed in a sturdy weatherproof aluminium casing. Supplied with car and mains chargers, lanyard and filters. Cat. ST-3362 00 $ • Light output: 1800 Lumens • Size: 72(Dia.) x 3/2(L)mm 4mm Piggyback Banana Plugs INTERNET> www.jaycar.com.au A low cost alternative for the DIY person, this butane gas soldering iron features adjustable tip temperature and a fold-out stand. Remove the soldering tip and you IMPROVED MODEL! have a flame torch for heatshrink etc. 46W Cat. TS-1111 95 $ 19. Soldering Pencil This soldering iron offers exceptional heat recovery. With its high insulation and low current leakage, soldering of precision flat ICs and CMOS is a breeze. Cat. TS-1430 95 $ 59. 7 Theremin Synthesiser MKII Kit Speedo Corrector MkII Refer: Silicon Chip December 2006 When you modify your gearbox or change to a larger circumference tyre, it will result in an inaccurate speedometer. This kit alters the speedometer signal up or down from 0% to 99% of the original signal. With this improved model, the input setup selection can be automatically selected and it also features an input LED indicator. Kit supplied with PCB with overlay and all electronic components. Cat. KC-5435 95 $ 49. Ref: Silicon Chip July 2006 By moving your hand Improved between the metal Model! antennae, create unusual sound effects. The Theremin MkII improves on its predecessor by allowing adjustments to the tonal quality and providing a better waveform. With a multitude of controls this instrument's musical potential is only limited by the skill and imagination of it's player. Kit includes stand, PCB with overlay, machined case with silkscreen printed lid, loudspeaker, pitch and volume Cat. KC-5426 antennae and all specified 95 $ electronic components. Magnetic Cartridge Preamp Kit Refer: Silicon Chip August 2006 This kit is used to amplify the 3-4mV signals from a phono cartridge to line level, so you can use your turntable with the CD or tuner inputs on your Hi-Fi amplifier. The design is suitable for 12" LPs, and also allows for RIAA equalisation of all the really old 78s. Kit includes PCB with overlay and all electronic components. Note: Only suitable for moving-magnet cartridges. • Power: 12VAC • Recommended magnetic cartridge AM-4020 $45.00 Cat. KC-5433 $ 95 39. 149. Darwin Store now Open until 7.30pm Protect and Extend the Life of Your Power Tool Rechargeable Batteries on Fridays! Ref: Silicon Chip December 2006 Ph (08) 8948 4043 Enhance the performance of the charger supplied with your power YOUR LOCAL JAYCAR STORE Freecall Orders: Ph 1800 022 888 NEW SOUTH WALES Albury Ph (02) 6021 6788 Alexandria Ph (02) 9699 4699 Bankstown Ph (02) 9709 2822 Blacktown Ph (02) 9678 9669 Bondi Junction Ph (02) 9369 3899 Brookvale Ph (02) 9905 4130 Campbelltown Ph (02) 4620 7155 Erina Ph (02) 4365 3433 Gore Hill Ph (02) 9439 4799 Hornsby Ph (02) 9476 6221 Newcastle Ph (02) 4965 3799 Parramatta Ph (02) 9683 3377 Penrith Ph (02) 4721 8337 Silverwater Ph (02) 9741 8557 Sydney City Ph (02) 9267 1614 Taren Point Ph (02) 9531 7033 Tweed Heads Ph (07) 5524 6566 Wollongong Ph (02) 4226 7089 VICTORIA Coburg Ph (03) 9384 1811 Frankston Ph (03) 9781 4100 Geelong Ph (03) 5221 5800 Melbourne Ph (03) 9663 2030 Ringwood Ph (03) 9870 9053 Springvale Ph (03) 9547 1022 Sunshine Ph (03) 9310 8066 QUEENSLAND Aspley Ph (07) 3863 0099 Mermaid Beach Ph (07) 5526 6722 Townsville Ph (07) 4772 5022 Underwood Ph (07) 3841 4888 Woolloongabba Ph (07) 3393 0777 AUSTRALIAN CAPITAL TERRITORY Belconnen Ph (02) 6253 5700 Fyshwick 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 Maddington Ph (08) 9493 4300 Northbridge Ph (08) 9328 8252 NORTHERN TERRITORY Darwin Ph (08) 8948 4043 NEW ZEALAND Christchurch Ph (03) 379 1662 Dunedin Ph (03) 471 7934 Glenfield Ph (09) 444 4628 Hamilton Ph (07) 846 0177 Manukau Ph (09) 263 6241 Newmarket Ph (09) 377 6421 Wellington Ph (04) 801 9005 Freecall Orders Ph 0800 452 9227 8 tools with this fantastic controller. It incorporates charge timeout, min and max temperature monitoring, Delta V charge detection, power and charge LED indicator and more. Suits both Ni-Cd and Ni-MH cells. Kit includes PCB with overlay, case and all electronic Cat. KC-5436 components. 95 $ 39. Two-Way SPDIF/Toslink Digital Audio Converter Kit Ref: Silicon Chip June 2006. This kit converts coaxial digital audio signals into optical or vice-versa. Use this bit stream converter in situations where one piece of equipment has an optical audio input and the other a coaxial digital output. Kit includes Toslink optical modules, PCB with overlay, case with screen printed lid and all electronic components. Cat. KC-5425 95 $ • Requires 9 - 12VDC power (use MP-3030 $32.95 not incl.) 24. DC Relay Switch Kit Ref: Silicon Chip November 2006 An extremely useful and versatile kit that enables you to use a tiny trigger current - as low as 400µA at 12V to switch up to 30A at 50VDC. It has an isolated input, and is suitable for a variety of triggering options. The kit includes PCB with overlay Cat. KC-5434 and all electronic components. 95 $ 14. USB Experimenter's Interface Kit Interface your computer to the real world. There are five digital and two variable gain analogue inputs. Eight digital and two analogue outputs are available. Supplied with all components, silk screened PCB, Cat. KV-3600 assembly manual, and software. 95 $ 69. IR Remote Extender MKII Kit Improved Ref: Silicon Chip October 2006 Model! Operate your DVD player or digital decoder using its remote control from another room. It picks up the signal from the remote control and sends it via a 2-wire cable to an infrared LED located close to the device. This improved model features fast data transfer, capable of transmitting Foxtel digital remote control signals using the Pace 400 series decoder. Kit supplied with case, screen printed front panel, PCB with overlay and all electronic components. Cat. KC-5432 • Requires 9 VDC power 95 $ and 2-wire cable 24. Voltage Monitor Kit Ref: Silicon Chip May 2006 This versatile kit will allow you to monitor the battery voltage, the airflow meter or oxygen sensor in your car. The kit features 10 LEDs that light up in response to the measured voltage, preset 9-16V, 0-5V or 0-1V ranges complete with a fast response time, high input impedance and auto dimming for night time driving. Kit includes PCB with overlay, LEDs and all electronic components. • 12VDC • Recommended box: Cat. KC-5424 UB5 HB-6015 $2.50 95 $ 19. HIGH PERFORMANCE ELECTRONIC PROJECTS FOR CARS BOOK There are 16 projects in total, ranging from devices for remapping fuel curves, to nitrous fuel mixture controllers, and more! The book includes all instructions, component lists, colour pictures, and circuit layouts. There are also chapters on engine management, advanced systems and DIY modifications. 150 pages! Nitrous Fuel Mixture / Motor Speed Controller It makes a great motor controller, to control an electronic water pump, additional fuel pump, cooling fans and more. It is suitable for use with most fuel injectors, or pumps and motors up to 10 amps. Kit supplied with PCB and all electronic components. PRICES VALID TO 28/02/07 19. Frequency Switch Kit Cat. KC-5382 95 $ 24. Cat. BS-5080 80 $ Relay activation! Switch a relay on or off depending on the frequency of the input. This could be used as a shift-light, over speed warning & more. Kit includes PCB and all electronic components. Cat. KC-5378 95 $ 35. FOR INFORMATION AND ORDERING TELEPHONE> 1800 022 888 INTERNET> www.jaycar.com.au Mater Maria College Scoops Technology Prize Pool SILICON CHIP has rewarded two students from Mater Maria Catholic College, Warriewood, with its inaugural “Excellence in Education Technology” awards, and the college itself with more than $6000 worth of electronics laboratory equipment. The awards had two divisions, both worth $5000. One was for any secondary school or college with an electronics curriculum and the other for universities and TAFEs. In the schools division, there were two awards made of $1000 each to the students submitting their major works for electronics in the Higher School Certificate, with $3000 going to the winning school/ college for electronic test and construction equipment. As it turned out, the judges awarded Mater Maria students with both individual prices and the college took out the major award. Leo Simpson, publisher of SILICON CHIP, said that with the magazine’s connections, the $3000 was turned into $6000 worth of gear. “We obtained gear from Jaycar Electronics, Altronics and Dick Smith Electronics, as well as bullet-proof digital multimeters from Yokogawa Australia” (see review this issue). “We believe that with this equipment, Mater Maria electronics laboratory will be the best-equipped in the state,” he said. “The teacher of electronics, Dave Kennedy, was speechless when he saw what he would be working with next year.” The $1000 cash prizes were awarded to two students, Lauren Capel and Matt McDonald. Lauren sourced a non-working 1940s vintage battery-operated valve radio receiver, restored and repaired it, then added a mains power supply and brought it into the twenty-first century with an MP3 player and miniature radio transmitter so she could play her MP3s through the radio. Matt’s project was a complete home security system, complete with SMS text messaging service to warn of intruders and mobile-phone operated remote control. Unable to find the alarm control he wanted in Australia, Matt sourced and imported a unit from Great Britain. Leo Simpson said that both projects demonstrated a great deal of ingenuity and were markedly different from the majority of Higher School Certificate major works entered. “Most students chose projects such as high power audio amplifiers for the home or car,” he said. “They reflect the interests of students of that age.” “But the projects Lauren and Matt produced showed that they thought outside the square. Much more research and documentation was needed in their projects than the majority, who in the main build SC their projects from kits of parts.” Our photo shows Dave Kennedy, electronics teacher at Mater Maria College, Leo Simpson and the two schools division winners, Matt McDonald and Lauren Capel. siliconchip.com.au February 2007  57 Low-Cost 50MHz Frequency Meter; Mk.2 By JOHN CLARKE This update of our very popular compact 50MHz Frequency Meter now has an internal battery pack or can run from a DC plugpack supply. It also incorporates a 10kHz rounding mode to enable 36MHz R/C transmitters using pulse position modulation (PPM) to be measured with an unambiguous reading. 58  Silicon Chip siliconchip.com.au measure radio control transmitters, the modulation used will often result in an incorrect value. More information on this feature is detailed in an accompanying panel. As before, the design is easy to build, since it uses the programmed PIC microcontroller to perform all the complex logic. Apart from that, there’s an LCD readout, a couple of low-cost ICs, two transistors, the 3-terminal low dropout regulator and a few sundry bits and pieces. Note that although we have specified this Frequency Meter at 50MHz maximum, typical units will be capable of measuring frequencies somewhat higher than this. In fact, our prototype meter was good for measurements to above 64MHz. LCD readout S INCE MANY of our readers will not be familiar with the 50MHz Frequency Meter presented in the October 2003 issue, we are presenting the design in full. No doubt kitset suppliers will bring out the updated version of the kit but many readers will want to update a kit they have already built. This is easy to do because there are only a few circuit and hardware changes and the PC board itself is unchanged. As far as the circuit is concerned, the major change is in the PIC microcontroller. We have used a PIC16F628A instead of the originally specified PIC16F84P, because we needed a larger memory. Other changes include an LM2940CT-5 low dropout regulator instead of the 78L05, an additional toggle switch on the front panel and the aforementioned internal battery pack. In other respects, the circuit is unchanged. Frequency meters are used in virtually all areas of electronics and are invaluable for servicing and diagnostics. Among other things, they are ideal for checking the operation of oscillators, counters and signal generators. This unit is auto-ranging and displays the frequency in Hz, kHz or MHz. This makes it easy to read, as it automatically selects the correct range for any frequency between 0.1Hz and 50MHz and inserts the decimal point in the correct place for each reading. Provision for prescaler If you want to measure frequencies siliconchip.com.au Main Features • Compact size (130 x 67 x 44mm) • • 8-digit reading (LCD) Automatic Hz, kHz or MHz indicator units • Prescaler kHz, MHz and GHz indicator units • Three resolution modes including 10kHz rounding • • • • 0.1Hz resolution up to 150Hz 1Hz resolution up to 16MHz 10Hz resolution above 16MHz Battery or DC plugpack supply above 50MHz you will need a prescaler that divides the input frequency to a range that the frequency meter can accept. A good example is our UHF 1000:1 Prescaler, presented in the October 2006 issue. Accordingly, our updated version of the 50MHz Frequency Meter includes a prescaler switch which changes the units from MHz to GHz, kHz to MHz and Hz to kHz. As already mentioned, for radio control modellers, the 50MHz Frequency Meter Mk.2 can be set to display the reading in 10kHz steps for frequencies above 16MHz. This is an important feature because when a standard frequency meter is used to A 2-line 16-character Liquid Crystal Display (LCD) shows the frequency reading. This has several advantages over LED displays, including much lower current consumption. In addition, the LCD can show all the units without resorting to the use of separate annunciators, as would be required with a LED display. Resolution modes Three resolution modes are available: (1) a low-resolution mode with fast updates, suitable for most measurements; (2) a high-resolution mode for greater precision when required; and (3) the 10kHz rounding up feature. In low-resolution mode, the resolution is 1Hz for frequencies from 1-999Hz and 10Hz for frequencies above this. The corresponding display update times are 1s from 1-999Hz and 200ms from 1kHz-50MHz. High-resolution mode provides 1Hz resolution for frequencies from 150Hz16MHz. Above 16MHz, the resolution reverts to 10Hz. The display update time is 1s. Below 150Hz in the high-resolution mode, the display has 0.1Hz resolution and a nominal 1s update time for frequencies above 10Hz. This 0.1Hz resolution makes the unit ideal for testing loudspeakers, where the resonance frequency needs to be accurately measured. Note that the update time is longer than 1s for frequencies below 10Hz. The three resolution modes are selected by pressing the Resolution switch. The meter displays “LOW”, February 2007  59 Parts List 1 PC board, code 04110031 for Dick Smith Electronics version; code 04110032 for Altronics version; 04110033 for Jaycar version – 121 x 61mm 1 plastic case, 130 x 67 x 44mm 1 front panel label to suit version, 125 x 64mm 1 LCD module (DSE Cat. Z 4170, Altronics Cat. Z 7000A or Jaycar Cat. QP 5515) 1 SPST toggle switch (S1) 1 pushbutton momentary contact switch (S2) 1 miniature SPDT toggle switch (S3) 1 panel-mount BNC socket 1 low-drift 4MHz crystal (Hy-Q HC49/U 4000.00kHz GG03E) (X1) 1 PC-mount 2.5mm DC socket 1 18-pin dual-wipe contact DIP socket (for IC3) 1 28-pin dual-wipe contact DIP socket (for DSE & Altronics LCD modules; see text); OR 1 14-pin dual-wipe contact DIP socket (for Jaycar LCD module) 1 14-way SIL pin header for the LCD sockets 4 M3 x 10mm countersunk screws 4 M3 nuts 4 M3 x 6mm cheesehead screws 4 M3 x 12mm tapped Nylon spacers 4 M3 Nylon washers 10 PC stakes 1 300mm length of 0.7mm tinned copper wire “HIGH” or “LOW 10kHz<at>>16MHz” to indicate which mode is currently selected. In addition, the selected resolution mode is stored in memory and is automatically restored if the meter is switched off and on again. In the 10kHz rounding mode, the frequency is rounded up to just show the next 10kHz frequency band for frequencies between 16MHz and 50MHz. When the display is showing frequency rounding the second line of the display indicates this with a “(10kHz Rounding)” indication. In low-resolution mode, the display will show 0Hz if the frequency is below 1Hz. By contrast, in the high60  Silicon Chip 1 60mm length of 75W coax 1 100mm length of hookup wire 1 1kW horizontal trimpot (code 102) (VR1) 1 10kW horizontal trimpot (code 103) (VR2) Semiconductors 1 MC10116N triple ECL differential line receiver (IC1) 1 74HC132 quad Schmitt trigger (IC2) 1 PIC16F628A/P microcontroller programmed with freqenc2. hex (IC3) 1 LM2940CT-5 low dropout regulator (REG1) 1 2N5485 N-channel VHF JFET (Q1) 1 BF450 PNP transistor (Q2) 3 BAW62 diodes (D1-D3) 1 1N4004 1A diode (D4) Capacitors 2 100mF 16V PC electrolytic 3 10mF 16V PC electrolytic 1 470nF MKT polyester 1 100nF MKT polyester 8 10nF ceramic 1 470pF ceramic 1 33pF NP0 ceramic 1 22pF ceramic 1 10-60pF trimmer (VC1) Resistors (1%, 0.25W) 1 910kW 7 470W 1 100kW 1 330W 1 47kW 4 100W 2 10kW 1 15W1W (optional) 2 2.2kW resolution mode, the display will show “No Signal” for frequencies below 0.1Hz. If the frequency is below 0.5Hz, the display will initially show an “Await Signal” indication before displaying the frequency. If there is no signal, the display will then show “No Signal” after about 16.6s. The 0.1Hz resolution mode for frequencies below 150Hz operates in a different manner to those measurements made at 1Hz and 10Hz resolution. Obtaining 0.1Hz resolution in a conventional frequency meter normally means measuring the test frequency over a 10s period. And that means that the update time is slightly longer than 10s. This is a long time to wait if you are adjusting a signal generator to a precise frequency. However, in this frequency meter, the display update period is 1s for frequencies above 10.0Hz, increasing gradually to 10s for frequencies down to 0.1Hz. So for normal audio frequencies, the display will update at 1s intervals. Just how this is achieved is explained below, when we discuss the block diagrams for the unit. The Prescaler switch causes the display to show the prescaler units in the LOW and HIGH resolution selections. When selected, the words “Prescaler units” are shown on the second line of the LCD. The prescaler units feature is not available for the 10kHz rounding feature because it is not required and would confuse the reading. Block diagrams Fig.1 shows the general arrangement of the frequency meter. It’s based mainly on the microcontroller (IC3). In operation, the input signal is processed and applied directly to a divide-by-256 prescaler inside IC3. The divided signal then clocks timer TMR0 which counts up to 256 before clocking Register A, an 8-bit register that counts up to 256 before returning to zero. Combining all three counters (the prescaler, TMR0 and register A) allows the circuit to count up to 24 bits, or a total of 16,777,216. By counting over a 1s period, it follows that the unit can make readings up to about 16.7MHz. However, if the frequency is counted over a 100ms period, the theoretical maximum that can be measured is just over 167MHz. As shown in Fig.1, the input signal is amplified (by Q1, IC1 & Q2) and fed to gating stage IC2a. This drives clocking stage IC2b which is controlled by IC3’s RA3 output. Normally, IC2b allows the signal to pass through to the prescaler at IC3’s RA4 input. IC3’s RB2 output controls gating stage IC2a so that signal passes through for either a 100ms period or a 1s period. During the selected period, the signal frequency is counted using the prescaler, timer TMR0 and register A. Initially, the prescaler, the timer and register A are all cleared to 0 and the RB2 output is then set to allow the input signal to pass through to the prescaler for the gating period (ie, for 100ms or 1s). siliconchip.com.au Fig.1: the block diagram of the 50MHz Frequency Meter for “normal” frequency measurements. The incoming signal is first amplified, then fed through a gating circuit to clocking stage IC2b. This then drives a divide-by-256 prescaler inside PIC microcontroller IC3 (ie, at the RA4 input). Fig.2: this is the alternative configuration for making high-resolution (ie, to 0.1Hz) measurements below 150Hz. In this case, the input signal is applied to the RA4 input as before. However, the prescaler is no longer clocked by the RA4 input but by an internal 1MHz clock instead. During this period, the prescaler counts the incoming signal applied to RA4. Each time its count overflows from 255 to 0, it automatically clocks timer TMR0 by one count. Similarly, whenever the timer output overflows from 255 to 0, it sets a Timer Overflow Interrupt Flag (TOIF) which in turn clocks Register A. At the end of the gating period, IC3’s RB2 output is cleared, thus stopping any further signal from passing through to the prescaler. The value of the count in TMR0 is now transferred to Register B. Unfortunately, the value in the prescaler cannot be directly read by IC3 and so we need to derive the value. This is done by first presetting register C with a count of 255. That done, the RA3 output is taken low to clock the prescaler and timer TMR0 checked siliconchip.com.au to see if it’s count has changed. If TMR0 hasn’t changed, the prescaler is clocked again with RA3. During this process, register C is decreased by 1 each time the prescaler is clocked. The process continues, with RA3 clocking the prescaler until timer TMR0 changes by one count. When this happens, it indicates that the prescaler has reached its maximum count. The value in Register C will now be the value that was in the prescaler at the end of the counting period. The processing block now reads the values in registers A, B and C. Based on this information, it then decides where to place the decimal point and whether to show Hz, kHz or MHz. The required value is then written to the LCD via the data and control lines (RB4-RB7 and (RA0-RA2). For the Prescaler units selection, the Hz units are shown as kHz, the kHz units are shown as MHz and the MHz units are shown as GHz. In the 10kHz rounding mode, frequencies above 16MHz are rounded up to the next 10kHz band. So for example a 36.44659MHz signal is rounded up to 36.450MHz. Alternative configuration If the input signal frequency is greater than 16MHz and the gating period is 1s, register A will initially have overflowed. In this case, the gating period is automatically changed to 100ms. Alternatively, if the high-resolution mode is selected and the frequency is below 150Hz, the frequency meter changes its configuration to that shown in Fig.2. In this case, the input signal is applied to the RA4 input as before. February 2007  61 Specifications • Input sensitivity: typically less than 20mV RMS from 1Hz to 100kHz rising to 50mV at 20MHz and 85mV at 50MHz. • • • • • Input Impedance: 1.1MW in parallel with about 10pF Frequency range: 0.1Hz to 50MHz or better Untrimmed accuracy: ±20ppm equivalent to 1000Hz at 50MHz Trimmed accuracy: ±10ppm from -20°C to 70°C Resolution: High Resolution Mode: 0.1Hz from 0.1-150Hz; 1Hz from 150Hz-16MHz; 10Hz from 16-50MHz. Low Resolution Mode: 1Hz from 1-999Hz; 10Hz from 1kHz-50MHz • Update time (approx.): 200ms for 10Hz resolution; 1s for 1Hz resolution; 1s for 0.1Hz resolution down to 10Hz, increasing to 10s at 0.1Hz • Display units: Hz from 0.1-999Hz; kHz from 1-999.999kHz; MHz from 1-50MHz • Current consumption: 65mA with 7.5-12V input Fig.3 (right): the circuit is based on microcontroller IC3. This processes the signals from the preceding amplifier stages and drives the LCD. Power comes either from a 9-12V DC plugpack or from a 7.5V battery. at the source. This loss is more than compensated for in the following amplifier stages. Next, the signal is AC-coupled to pin 4 of amplifier stage IC1a via a 100mF electrolytic capacitor and a parallel 10nF capacitor. The 100mF capacitor is sufficiently large to allow for a low frequency response of less than 1Hz. However, this capacitor loses its effectiveness at higher frequencies due to its high internal inductance and the signal is coupled via the 10nF capacitor instead. Differential line receivers However, the prescaler is no longer clocked by the RA4 input but by an internal 1MHz clock. Basically, what happens is that the RA4 input is monitored for a change in state – ie, from a low voltage to a high voltage – which indicates a signal at the input. When this happens, the prescaler is cleared and begins counting the 1MHz internal clock signal. The overflows from the prescaler and timer TMR0 are carried to register A as before. Counting continues until the input signal goes low and then high again, at which point counting stops. If the counting causes register A to overflow, then the display will show no signal (this will happen after 16.7s if the signal does not go low and high again). Conversely, if the counting is within range, the prescaler value is determined by clocking IC2b using the RA3 output as before. From this, it follows that if the input frequency is 1Hz (ie, a 1s period), the value in the A, B and C registers will be 1,000,000. That’s because the prescaler is clocked at 1MHz for 1s. Similarly, the count will be 100,000 for a 10Hz signal and 10,000 for a 100Hz input signal. Finally, the value in the registers is divided into 10,000,000 and the decimal point placed immediately to the left of the righthand digit. This gives a direct readout in Hz with 0.1Hz resolution on the LCD. 62  Silicon Chip This technique cannot be used for measuring very high frequencies because the value in the counter becomes smaller as the frequency increases and so we begin to lose accuracy. For example, at 500Hz, the counted value would be 2000 and at 500.1Hz the counted value would be 1999. The result of the division of 1999 into 10,000,000 would be 500.2 instead of the 500.1 required. The 0.1Hz resolution has therefore been restricted to readings below 150Hz to ensure accuracy of the calculation. Circuit details Refer now to Fig.3 for the full circuit details. The input signal is AC-coupled to the unit via a 470nF capacitor to remove any DC component. This signal is then clipped to about 0.6V peak-to-peak using diodes D1 & D2, with current limiting provided by the 100kW series resistor. The 22pF capacitor across the 100kW resistor compensates for the capacitive load of the diodes. From there, the signal is fed to the gate of Q1, a 2N5485 JFET. This transistor provides high input impedance, which is necessary to ensure a wide frequency response. Q1 is self-biased using a 910kW resistor from gate to ground and a 470W source resistor. It operates with a voltage gain of about 0.7, which means that the signal is slightly attenuated IC1a is one of three differential line receivers in an MC10116N IC. It’s biased via the DC output at pin 11 and this is decoupled using a 10mF electrolytic capacitor and a paralleled 10nF ceramic capacitor. The voltage is then applied to the wiper of trimpot VR1 (Offset Adjust) and this allows adjustment of the input bias voltage. In operation, IC1a is run open-loop (ie, without feedback) so that it provides as much gain as possible. Even so, it only operates with a voltage gain of about seven times. It’s differential output signals appear at pins 2 & 3 and are applied to the differential inputs (pins 12 & 13) of IC1b. Note that the differential outputs have 470W pull down resistors, as they are open emitters. In fact, the MC10116 IC is an emitter-coupled logic (ECL) device. Unlike IC1a, IC1b has negative feedback provided by the two associated 100W resistors. This reduces the gain of this stage to just below two. The third stage using IC1c employs positive feedback and so it functions as a Schmitt trigger rather than as an amplifier. Its hysteresis is around 450mV and this means that the signal swing on its differential inputs must be greater than this in order to provide an output. In operation, the output signal at pins 6 & 7 swings from 4.3V when high to 3.4V when low. This needs to be level-shifted to provide normal CMOS input levels to the gating cirsiliconchip.com.au siliconchip.com.au February 2007  63 Fig.4: follow this layout diagram to build the Altronics version. Note that trimmer capacitor VC1 mounts on the track side of the board – see photos. 3 output remains high and the input signal is blocked. So, in summary, the signal is allowed through to IC2b when RB2 is high and is blocked when RB2 is low, as described previously. IC2b normally has its pin 5 input held high via IC3’s RA3 output, so that the signal from IC2a is again inverted at pin 6. When RB2 is brought low, pin 3 of IC2a remains high and so pin 4 of IC2b is also high. This allows RA3 to clock the RA4 input via IC2b. Fig.5: this is the layout to follow if you are building the Jaycar version. Fig.6: this is the layout for the Dick Smith Electronics version. Note that DSE may not be offering a kit for the new Mk.2 unit. However, this layout lets you upgrade existing Mk.1 versions of the DSE kit. cuit (IC2a) and this is done using PNP transistor Q2. IC2a is a Schmitt NAND gate. It inverts the signal on its pin 1 input 64  Silicon Chip when pin 2 is held at +5V by IC3’s RB2 output (ie, the signal passes through to the pin 3 output but is inverted). Conversely, when RB2 is at 0V, IC2a’s pin Driving the LCD IC3’s RA0-RA2 outputs drive the control inputs to the LCD module and select the line and the position of the character to be displayed. Similarly, RB4-RB7 drive the data inputs (DB4DB7) on the LCD module. A 470pF capacitor on the E-bar (enable control line) is included to slow down the rise and fall times of the square wave from IC3. A 4MHz crystal connected between pins 15 & 16 of IC3 provides the clock signals for IC3. The recommended crystal has low drift but a standard 4MHz crystal could be used if accuracy is not critical. The capacitors at pins 15 & 16 provide the necessary loading for the crystal, while VC1 allows the clock frequency to be “tweaked” slightly to provide calibration. Power supply Power for the circuit is derived from either a 9-12V DC plugpack or a 7.5V battery made up using five AA cells. siliconchip.com.au The LCD module is secured to the lid of the case using four M3 x 6mm cheesehead screws, four M3 nuts and four M3 x 10mm tapped Nylon spacers. Make sure that all polarised parts on the counter board are correctly orientated. You can choose to operate from batteries or a DC supply but not both. Diode D4 protects the circuit against reverse polarity protection when using a plugpack supply, while regulator REG1 provides a +5V supply rail to power the circuit. The specified regulator is a low dropout type so that the meter will still operate when the batteries have dropped to 5V. If a battery is used, it connects to the cathode side of D4; ie, it bypasses the reverse polarity protection. This means that D4 can be left out of circuit (along with the DC socket) if the unit is to be battery powered. If you wish to use rechargeable cells, then it is recommended to use an extra cell to obtain more voltage. In this case you could replace D4 with a 15W 1W resistor to enable charging. Make sure you get the polarity correct. If you are concerned about polarity, a Schottky diode (1N5819) could also be included in series with the resistor. LM2940CT-5 low dropout regulator. In addition, you will need to drill an extra hole in the front panel to accommodate the additional switch. Each LCD plugs directly into its intended PC board, which means that there are no external wiring connections except to the BNC input socket, Construction The SILICON CHIP 50MHz Frequency Meter Mk.2 can be made in one of three versions, depending on where you buy the kit. That’s because the LCD modules available from Dick Smith Electronics (DSE), Altronics and Jaycar are all different and so a different PC board has been designed to suit each module. These boards are coded 04108031 (DSE), 04108032 (Altronics) and 04108033 (Jaycar). If you are buying a kit, make sure you get the updated version and not the original version described in October 2003. If you decide to purchase the earlier kit or you are modifying an existing kit, you will need a new programmed PIC16F628A, a miniature SPDT toggle switch and an Table 2: Capacitor Codes Value 470nF 100nF 10nF 470pF 33pF 22pF mF code EIA Code 0.47mF 474 0.1mF 104 .01mF 103 NA 471 NA   33 NA   22 IEC Code 470n 100n   10n 470p   33p   22p Table 1: Resistor Colour Codes o o o o o o o o o o siliconchip.com.au No.   1   1   1   2   2   7   1   4   1 Value 910kW 100kW 47kW 10kW 2.2kW 470W 330W 100W 15W 4-Band Code (1%) white brown yellow brown brown black yellow brown yellow violet orange brown brown black orange brown red red red brown yellow violet brown brown orange orange brown brown brown black brown brown brown green black brown 5-Band Code (1%) white brown black orange brown brown black black orange brown yellow violet black red brown brown black black red brown red red black brown brown yellow violet black black brown orange orange black black brown brown black black black brown brown green black gold brown February 2007  65 Fig.7: this diagram shows how the unit is installed inside the case. Be sure to use Nylon spacers and washers where indicated. switch S3 and to the battery holders. The unit is housed in a plastic case measuring 130 x 67 x 44mm, with the LCD module protruding through a cutout in the front panel. The Dick Smith version has the power switch on the righthand side and the signal input applied to the BNC socket at the top left of the box. By contrast, both the Altronics and the Jaycar versions have the power switch at the top left, while the input socket is mounted on the top right of the box. This difference comes about because the display readout for the DSE LCD module is upside down compared to the other two modules in relation to the input terminals. Note that the unit shown in the photos is the Jaycar version but both the Altronics and DSE modules were fully tested. Figs.4-6 shows the PC board layouts for the three versions. Begin by check- ing that you have the correct PC board for the LCD module you are using. That done, check the mounting holes for the LCD module against those on the PC board (the holes must be 3mm in diameter). Check also that holes are large enough to mount switch S2 and the DC input socket. Next, install all the wire links and resistors, using the accompanying resistor colour code table as a guide to selecting each value. It’s also a good idea to check the resistors with a digital multimeter just to make sure. IC1 and IC2 can go in next, taking care to ensure that they are correctly oriented. Then install a socket for IC3 but don’t install the microcontroller yet. The diodes and capacitors can now all be installed, followed by REG1 and transistors Q1 & Q2. Note that REG1 mounts using PC stakes and is mounted horizontally to cover IC3. Note also that some of the parts must sit with their bodies parallel to the PC board. These include crystal X1, its adjacent 470pF capacitor and the 10mF capacitor adjacent to switch S1 on the Jaycar version (so it doesn’t later foul S3), plus the 10mF and 100mF capacitors on the Altronics version (so that they don’t foul the LCD module). It’s just a matter of bending their leads at right angles before installing them on the board. Similarly, the top of transistor Q2 must be no higher than 10mm above the PC board so that it doesn’t interfere with the LCD module (all versions). The next step is to install the socket for the LCD module. Both the DSE and Altronics versions use a 28-pin DIL IC socket that is cut in half to obtain a 14-way strip socket which is then soldered in place. By contrast, the Jaycar Here’s another view of the completed PC board. Note how regulator REG1 is mounted face down over IC3 and the adjacent 100nF capacitor, with its three leads soldered to PC stakes. 66  Silicon Chip siliconchip.com.au version uses a 14-pin IC socket which is cut into two 7-way strips which are then installed side-by-side. Once the sockets are in, install PC stakes for the “+” and “-” supply connections (near D4) and for the signal input and GND connections. These PC stakes should all be installed from the copper side of the board. PC stakes are also used to mount switch S1. These should be trimmed so that when the switch is mounted, its top face is 20mm above the top surface of the PC board. Be sure to orient S1 with its flat section facing towards the right, as shown in Figs.4-6. The remaining parts can now be installed on the board. These parts include switch S2, the DC socket, trimpots VR1 & VR2, crystal X1 and trimmer capacitor VC1. Note that VC1 is mounted on the underside of the PC board, so that it can be adjusted without having to remove the LCD module. Front panel The front panel (ie, the case lid) must be drilled and a cutout made to accommodate the three switches and the display. However, if you have purchased a kit, then you probably won’t have to worry about this. It will also be necessary to drill the mounting holes for the LCD module. Note that these should be countersunk so that the intended screws sit flush with the surface of the lid – see Fig.7. That done, the adhesive label can be attached to the panel with the cut-outs made using a utility knife. Kit versions are supplied with screen-printed labelling. In that case, countersunk screws will not be necessary. BNC SOCKET NYLON WASHER NYLON WASHER TRIMMER VC1 The PC board is secured by plugging it into the matching header pins on the LCD module and installing four screws to fasten it to the spacers. Note the Nylon washers under the top two screw heads – these are necessary to prevent shorts to adjacent tracks. The inset at top-left shows an enlarged view of VC1. Now press the Resolution switch – the display should show “HIGH”. It should then show “Await Signal” when the switch is released. If the switch is then pressed again, the display should show “LOW”. A third press will bring up the LOW 10kHz<at>>16MHz mode. Final assembly Refer to Fig.7 for the final assembly details. As shown, the LCD module is secured to the case lid using four M3 x 10mm CSK screws, four M3 nuts (used as spacers) and four 12mm-long tapped Nylon spacers. The PC board is then secured to the bottom ends of the four spacers. Use Nylon washers for the underside of the PC board to prevent shorting any tracks with the screws (see above photo). You will have to drill a 9mm dia­ Testing Now for an initial test before IC3 or the LCD are plugged in. Apply power and check that +5V is present on pin 16 of IC1, pin 14 of IC2 and pins 4 & 14 of IC3. If this is OK, disconnect power and install IC3 in its socket, taking care to ensure it goes in the right way around. Plug the LCD module into its matching socket and temporarily fit a couple of 12mm tapped Nylon spacers to support it on the PC board. Apply the power again and check that the display shows either 1Hz or 0Hz. If not, adjust VR2 for best display contrast. VR1 should be adjusted so that the display shows 0Hz when the signal input terminals are shorted. siliconchip.com.au Fig.8: the two battery holders (4 x AA and 1 x AA) must be wired in series as shown here. Add an extra AA holder if you are using rechargeables. February 2007  67 Checking The Frequency Of Radio Control Transmitters W HEN MODEL ENTHUSIASTS get together they often want to fly their radio-controlled aeroplanes (or drive their radio-controlled cars or boats) in a competition-based meet. With so many radio controls being used they must each operate on a different band to avoid interference between the controllers. Having a device that can immediately check each transmitter’s operating frequency is a great asset because it can tell immediately if there is going to be a frequency conflict. In that case, they can change the crystal frequency on one of the transmitters and for its receiver. Radio transmitters operate on the 27MHz band, 29MHz band, 36MHz band and 40MHz band. However, the synthesised modules (crystal controlled) are only available on the 36MHz band and this is by far the most popular band. On this band, there is PPM (pulse position modulation) and PCM (pulse code modulation) used for the transmission. With PCM the frequency reading on a meter will be correct since the modulation is symmetrical and the frequency swings will average out. For PPM the frequency reading on a meter will be a few kHz low because of the asymmetrical dwell times on the high low parts of the modulation. The PPM frequency reading can be most confusing at times. To understand why let’s consider an example. The 36MHz band runs in 10kHz steps from 36.010MHz to 36.590MHz. If we have a crystal in the transmitter that is set at 36.450MHz, the reading on a standard frequency meter will show a lower value at say, 36.44646MHz. But with our frequency meter in 10kHz rounding mode, it converts the 36.44646MHz count to 36.450MHz. There is no need to connect the RC transmitter directly to the frequency meter for these readings. Just bring the transmitter’s antenna close to an antenna that’s connected to the meter as shown in one of the photos. We made our antenna from an old Ethernet cable. Just cut the cable so that you have a length of 200mm or so from the BNC socket, then strip off the other sheath insulation and the woven shield, leaving just the inner insulated wire. This can then be covered with a length of heatshrink sleeving to provide extra stiffening and protection. The battery holders are attached to the bottom of the case using epoxy adhesive. 68  Silicon Chip meter hole in one side of the box to provide access to the DC socket if you are powering the unit from a plugpack. This hole should be positioned midway along one side and about 10mm down from the top edge of the case. If the unit is to be battery-powered, you will need to solder the battery leads to the supply PC stakes on the underside of the board. The batteries can be secured to the bottom of the case by mounting them in suitable holders. We used a 4 x AA holder and a single AA holder – see Fig.8. Use an extra AA holder if you are using rechargeables. The BNC input socket is mounted in a slot in the top side of the case (see photo below) and is wired using 75W cable to the two signal input PC stakes on the underside of the PC board. In practice, the slot must be made so that the socket can be either slid in or out, along with the PC board and display assembly. We made the slot just wide enough to allow the “flat” side of the BNC socket to fit. This prevents the socket from turning in the slot when an input connector is attached. Finally, switch S3 is wired to its terminals as shown using hookup wire. Calibration The completed 50MHz Frequency Meter can be calibrated against the 15.625kHz line oscillator frequency in a colour TV set. Fortunately, you don’t need to remove the back of the set to do this. Just connect a long insulated wire lead to the input socket and dangle it near the back of the TV set. It’s then just a matter or adjusting VC1 so that the meter reads 15.625kHz when the resolution is set to “High”. Note: the TV must be showing a PAL program, not NTSC (15.750kHz). If there is insufficient adjustment on VC1 to allow calibration, the 33pF capacitor at pin 15 of IC3 can be altered. Use a smaller value if the frequency reading is too high and a larger value if the frequency reading is too low. Usually, the next value up or down from 33pF will be sufficient; use either 27pF or 39pF. If you require greater accuracy, the unit can be calibrated against the standard 4.43MHz colour burst frequency that’s transmitted with TV signals. The best place to access this frequency is right at the colour siliconchip.com.au Fig.9: this front-panel artwork suits both the Altronics and the Jaycar versions. Fig.10: use this artwork to upgrade an existing Dick Smith Electronics Mk.1 version. burst crystal inside a colour TV set. This crystal will usually operate at 8.8672375MHz (ie, twice the colour burst frequency), although some sets use a 4.43361875MHz crystal. Be warned though: the inside of a colour TV set is dangerous, so don’t attempt to do this unless you are an experienced technician. There are lots of high voltages floating around inside a colour TV set and you could easily electrocute yourself if you don’t know what you are doing. In particular, note that much of the circuitry in a switchmode power supply circuit (as used in virtually all late-model TV sets) operates at mains potential (ie, many of the parts operate at 240VAC). In addition, the line output stages in some TV sets also operate at mains potential – and siliconchip.com.au that’s in addition to the lethal EHT voltages that are always present in such stages. Note too that some TV sets (particularly older European models) even have a “live” chassis, in which all the circuitry (including the chassis itself) operates at mains potential (ie, 240V AC). Usually, there will be a label on the back of the set advising of this but don’t take it for granted. Don’t even think of messing about with this type of set. In short, don’t attempt the following calibration procedure unless you are very experienced and know exactly what you are doing. Assuming that you know what you are doing (and the set has a grounded chassis), you will need to make up an insulated probe with a 10MW resistor in series with the input plus a ground lead. This probe is then connected to one side of the colour burst crystal and VC1 adjusted so that the meter reads either 8.867237MHz or 4.433618MHz (resolution set to high mode). Make sure that the probe has no effect on the colour on the TV screen when it is connected to the colour burst crystal. If it does, it means that the probe is loading the crystal and altering its frequency. In that case, try connecting the probe to the other terminal of the crystal. That’s it – your new 50MHz Frequency Meter Mk.2 is now calibrated SC and ready for action. Footnote: a complete kit of parts for the 50MHz Frequency Meter MK.2 is available from Jaycar Electronics (Cat. KC-5440). February 2007  69 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. PICAXE 4-channel RF remote switch As described in the “Reliable 4-Channel RF Switch” (September 2006), the outputs from low-cost RF remote control modules often need to be conditioned to eliminate noise-induced effects. For basic applications, this might consist of 70  Silicon Chip a simple monostable circuit and “set-reset” latch in line with each output. To simplify construction, these functions can be integrated into a PICAXE microcontroller (IC1) running some simple BASIC code, as demonstrated by this design. It uses an Oatley Electronics (www. oatleye.com) 4-channel receiver module (RX7) and matching transmitter (TX7). After a short power-up delay, the program scans for a logic high level on any of its four inputs, which may originate from the UHF module outputs or a pushbutton switch (S1-S4). When an input goes high, the matching output is immediately toggled. A short (100ms) delay is siliconchip.com.au Program Listing: Remote Control Switch ' RF Remote Control Switch let pins = 0 pause 200 main: if input0=0 then test1 toggle 0 check0: if input0=1 then check0 goto delay test1: if input1=0 then test6 toggle 1 check1: if input1=1 then check1 goto delay test6: if input6=0 then test7 toggle 3 check6: if input6=1 then check6 goto delay test7: if input7=0 then main toggle 2 check7: if input7=1 then check7 Sinewave-to-digital clock shaper This circuit can be used to step up a sinewave at its input to sufficient amplitude to drive an ACMOS Schmitt trigger (IC1a) to produce a CMOS-level clock signal output. Trimcap VC1 is adjusted to minimise the detector output voltage at “Vnull”. While the circuit Q is low, the phase shift between the input sine­ wave and the input to the 74AC14 Schmitt trigger varies significantly when the tuned circuit is adjusted through resonance. For precision applications, low temperature coefficient, high Q inductors and capacitors must be used to minimise the phase shift variation over time and temperature. The circuit was used as a clock shaper in a GPS timing circuit, where the output signal was divided down to 1Hz for comparison with the receiver’s PPS output. The PPS signal from a modern timing GPS receiver (after correction for known pulse quantisation errors) will have an error of a few nanoseconds RMS. To preserve the accuracy of the measurement, the phase shift through the clock shaper must be stable to better than 1ns. With an observation time of around 1 day, a frequency error of a few parts in a trillion is easily measured. To achieve this level of stability, the propagation delay through the divider chain (not shown) must also be sufficiently stable. Bruce Griffiths, Hamilton, NZ. ($35) ' Short delay for switch debounce. ' Increase delay significantly if load ' switching causes unreliable operation. delay: pause 100 goto main then executed before scanning the inputs again. As noted in the program listing, the pause value (towards the end of the program) can be increased as necessary to eliminate false signalling that may occur when switching inductive loads. The circuit was used to remotely control overhead lighting but is equally applicable to many other remote switching tasks. Claude Zambelli, Nunderi, NSW. ($45) siliconchip.com.au Contribute And Choose Your Prize As you can see, we pay good money for each of the “Circuit Notebook” items published in SILICON CHIP. But now there are four more reasons to send in your circuit idea. Each month, the best contribution published will entitle the author to choose the prize: an LCR40 LCR meter, a DCA55 Semiconductor Component Analyser, an ESR60 Equivalent Series Resistance Analyser or an SCR100 Thyristor & Triac Analyser, with the compliments of Peak Electronic Design Ltd www.peakelec.co.uk So now you have even more reasons to send that brilliant circuit in. Send it to SILICON CHIP and you could be a winner. You can either email your idea to silchip<at>siliconchip.com.au or post it to PO Box 139, Collaroy, NSW 2097. February 2007  71 Circuit Notebook – Continued Tachometer & elapsed time accumulator This design was produced for use with a vehicle-mounted weed sprayer unit, which is powered by its own 9BHP petrol engine. The addition of a tachometer and engine run-time logger ensures that the spray pump is run at the correct speed and the engine serviced at the recommended intervals. The unit is designed for 2- or 4-stroke single-cylinder petrol engines. It can simultaneously display the engine speed and the session and total engine run times in hours and minutes. The session run time is the sum of the interval(s) in which the engine has been operating since the unit was last switched on. The total run time is stored in IC2’s EEPROM and is simply the sum of all the session run times, including the present one. An LCD readout is used to ensure visibility in bright sunlight. The prototype uses a 16-character x 2-line module from Jaycar Electronics, Cat. QP5515 (check for pin-out variances if other brands are substituted). The displayable speed range is 472-999 RPM, while run time range is 0-999 hours 59 minutes. Run time inaccuracy should not be worse than 0.0064% of reading, not accounting for tolerances in the 72  Silicon Chip 4MHz crystal. The display refresh rate is every second. Transformer T1 is wound on a powdered iron toroidal core (Jaycar Cat. LO-1244 or similar) using 0.63mm-diameter enamelled copper wire. The primary has 11 turns and an inductance of about 10mH. Each secondary has 22 turns and an inductance of about 40mH. The primary winding of T1 is capacitively coupled to the engine spark plug lead by using a couple of plastic cable ties to bind the latter to a pickup wire over a length of about 10-15cm. Doubling the pickup lead back once over this length was found to give a consistent RPM reading. This sensor comprises a tuned circuit, which is energised when the HT voltage on the spark plug lead drops very suddenly just after the spark is initiated. A damped oscillation at about 8MHz (with a decay time constant of about 2ms) is generated in the secondary of T1, which is full-wave rectified by diodes D2 & D3. The 7555 monostable has an output pulse width of about 5.2ms and acts to filter out any unwanted excitations of the tuned circuit during any single spark interval. Note that many small 4-stroke engines use a “wasted-spark” ignit­ion system and these must be treated as 2-stroke engines as far Alexand er is this m Radford onth’s winne Peak At r of a las Instrum Test ent as this tacho­meter is concerned. Unfortunately the alternating useful and wasted sparks vary greatly in strength due to the differing pressures in the engine cylinder and this makes it more difficult to obtain a consistent trigger signal. An optical sensor or one deriving its signal from a battery charging coil in the engine may give better results if the unit is fitted permanently to a specific engine. Switch S1 selects either 2- or 4-stroke operation. Switch S2 is used to reset the total engine run time counter to zero. To perform this reset, it is necessary to switch on the tachometer after S2 has been set to the closed position. As soon as the run time reads 000:00, move S2 back to the open position. The unit works by counting and recording the arrival time of positive-going edges at the RB0/INT input (pin 6) of PIC microcontroller IC2 during a 508.416ms gating period. Over the remainder of each operating cycle, which lasts almost 1s, the micro’s program calculates and displays the RPM reading and the session and total run times. The source code for the PIC micro is available for download from the SILICON CHIP website. Alexander Radford, Putney, NSW. siliconchip.com.au r ur list plie o Y cia up e s sp less re wi 01010101 Telelink Communications  Quality radio products Commercial product design capability  Engineering services and support What are you looking for in wireless data comms? Cheap and nasty imports that will probably let you down when you can least afford it. . . or quality, world-renowned wireless products that can not only be relied on, but have the technical backup and stock guarantees that you need. Telelink Communications have been in the Wireless business since 1986 and are now proud to distribute world-famous Circuit Design Inc products (from Japan) throughout Australia. We offer full technical support and backup - and are happy to advise YOU on the best wireless solution for your particular problem. Full range of MU-1 434MHz Embedded Low Power Radio Modem Australasian Distributors products immediately available * Is designed and made in Japan * 64 channels programmable within the 433MHz ISM band * Has standalone full data repeater functionality, built in. * Has line-of-sight range in excess of 1km Telelink tested – see www.cdt21.com/products/ modem/mu1/mu1_06.asp * Low current consumption * Is designed and made in Japan * 6 digital I/O straight out of the box! * Stand by mode in TX module * 4 operation modes in RX * Low voltage and consumption current * Compact body * MSK modem equipped * Long range control Telelink Communications CDT-RX / TX-01 UHF Narrow Band Single Channel Telemetry Module Australasian Distributors PO Box 5457, North Rockhampton, Qld 4702 Phone (07) 4934 0413 Fax (07) 4934 0311 Web: www.telelink.com.au email: sales<at>telelink.com.au TAKE YOUR PIC Picaxe.com.au DISTRIBUTOR: MicroZed.com.au Developed for students, & professional performance makes PICAXE the most easy-to-use micro ever: PICAXE “programmer" is two resistors and a 4.5V battery! PHONE 1300 735 420 FAX 1300 735 421 24 Hours ALL PICAXE ITEMS ON OUR SHELVES! STOCKISTS siliconchip.com.au In AUSTRALIA: altronics.com.au (Retail and Mail Order) oatleyelectronics.com School Electronic Supplies In NEW ZEALAND sicom.co.nz surplustronics.co.nz (School orders only – John - 03 8802 0628) February 2007  73 Circuit Notebook – Continued Picaxe-controlled MP3 doorbell Here’s how to add custom doorbell music and sound effects to your home using an old Philips USB-stick MP3 player (KEY006) or similar. In this design, multiple sound clips can be uploaded to the stick and replayed with the aid of a PICAXE microcontroller. To keep costs low, the audio output from the player is amplified by a discarded cassette deck, which feeds several speakers about the house, including one at the front porch. When a visitor presses the doorbell switch, the PICAXE micro powers up the deck and “presses” the play button on the MP3 player. The left channel plays on the inside speakers and the right channel plays on the outside speaker. When the sample has finished playing, the PICAXE fast-forwards the player to the next track and pauses it ready for the next push of the doorbell. In more detail, five pushbutton switches (S2-S6) give control over the MP3 player’s basic functions (pause/ play, fast-forward, rewind, volume up & volume down) with the aid of a simple resistive ladder. The end of the ladder (labeled “CONTROL”) is wired to the player via one contact of a 4-way jack. Mosfets (Q2 & Q3) in parallel with two of the switches allow PICAXE IC1 to control the pause/play and fastforward functions via two port outputs (P2 & P4). A third output (P0) controls Mosfet Q1, which in turn controls a relay (RLY1) to switch power to the cassette deck. Op amp IC1 buffers the audio signal from the player’s 74  Silicon Chip left signal output and in conjunction with trimpot VR1 acts as an adjustable voltage comparator. Its output is peak detected by D1 and a 22mF capacitor and the result fed into one of the microcontroller’s two inputs (P1). This arrangement is used to detect when a track has finished playing and to ensure that it operates relisiliconchip.com.au Program Listing: MP3 Doorbell userwait: for bcounter = 1 to 200 if pushbutton = 1 then playtrack pause 100 next bcounter 'MP3 Doorbell symbol pauseplay = 4 symbol pushbutton = pin3 symbol fastforward = 2 symbol peakdetin = 1 symbol powerout = 0 high fastforward pause KEYDOWNMS low fastforward pause KEYUPMS goto userwait symbol wcounter = w0 symbol bcounter = b2 symbol peaklev = b3 symbol KEYDOWNMS = 200 symbol KEYUPMS = 1000 start: input pushbutton input peakdetin low pauseplay low fastforward low powerout pause 2000 'duration of a button push 'duration of the delay after a button push playtrack: high powerout high pauseplay pause KEYDOWNMS low pauseplay 'startup delay ' Hold pause/play button down for several seconds to start. poweron: high pauseplay pause 3000 low pauseplay pause 3000 for wcounter = 1 to 5000 readadc peakdetin, peaklev if peaklev > 0 then playbackstarted pause 1 next wcounter ' No audio detected, so the mp3 player is probably off - try to restart. goto start ' Press fastforward then pause again immediately. advancetrack: high fastforward pause KEYDOWNMS low fastforward pause KEYUPMS high pauseplay pause KEYDOWNMS low pauseplay pause 3000 ' Powerup the output amp, unpause the track, start playing ' and wait for non-silence. If silence lasts for 5 seconds ' then reset system. playbackstarted: ' Allow to keep playing until at least 1s of continuous silence. waitforsilence: 'takes awhile to catch up for wcounter = 1 to 1000 readadc peakdetin, peaklev if peaklev > 0 then waitforsilence pause 1 next wcounter ' Powerdown the output amp, reset to next track. ' Wait for user input, press fastforward every 20s ' to prevent auto powerdown. ably, an inaudible, low-level 20Hz tone can be superimposed over all recordings. The micro’s second input (P3) is wired to the doorbell switch (S1) via a low-pass filter. While waiting for the doorbell switch to be pressed, the micro “pushes” the fast-forward button every 20s to prevent the player from automatically powering down – see the accompanying program flow chart for details. Power can be provided by a 9V DC plugpack. Diode D1 affords siliconchip.com.au low powerout goto advancetrack reverse polarity protection. A 7805 3-terminal regulator (REG1) reduces the input to +5V to power the majority of the circuit as well as the MP3 player, which is hooked up via a USB receptacle. All the tracks on the MP3 player have the left channel recorded with the internal doorbell sound plus 20Hz control tone, while the right channel carries the sound heard by the visitor. As it turns out, pausing MP3-formatted files chops a random amount off the front of the sample (up to 2s), which was judged unacceptable. Fortunately, there was no such problem when using WMA files. About 40 doorbell sounds are used on the prototype – from steam trains and fanfares through to Darth Vader and Monty Python. Changing them is a simple matter of unplugging the MP3 player, connecting it to the PC and downloading the correctly formatted WMA files. Richard van Wegen, Adelaide, S.A. ($50) February 2007  75 PRODUCT SHOWCASE Yokogawa’s “bulletproof” 734/02 true RMS DMM A few weeks ago, as we were assembling (with optional probe) (-50° to 800°C range); the prizes for Mater Maria College as part of capacitance (5nF to 50mF ranges); continuity their win in the SILICON CHIP Awards for Excel(buzzer) to 500W); diode check and even duty lence in Education Techology, we had a visit cycle (10-90%). from a sales rep from Yokogawa Australia, exUnlike most modern meters, it will also tolling the virtues of their new 734/02 DMMs. handle an AC voltage with DC component (or I was recounting to him a story of my days vice versa!); Decibels; relative values from the in early high school (just a few hundred short reference measurement; minimum, maximum months ago) when I knew even less about elecand average values; there are buttons for tricity and electronics than I do now. I knew range, data, peak and auto hold and you can that there were 240 volts in a power point but I also save a value to memory. wanted to know how many Ohms. So I pushed in The meter users ∆Σ modulation for A/D the multimeter probes and turned the power on. conversion, which enables fast and more Ummm – lots! Certainly more than enough to accurate measurement. The display updates wrap the pointer around the stop on the 200H three times per second and accuracy is and also let lots of smoke out . . . outstanding: on the 50 to 100V DC ranges, The guy from Yokogawa laughed and said “here, for example, it’s 0.03% +2. Accuracy of the watch this.” He proceeded to switch the DMM AC voltage ranges depends on frequency onto its Ohms range and plug the probes into a but from 20Hz to 10kHz it’s 0.4% +30. nearby (live!) power outlet.The multimeter didn’t With an optional commueven blow a fuse. Or anything else. In fact, it didn’t nications pack (with or much react at all. without RS-232C cable) “These things are bulletproof,” he said. “They’re you can also download perfect for schools and colleges where you don’t measurement data to know what they’re going to be subjected to, a personal computer or also for apprentices and juniors who printer. You can also get a take great delight in blowing up carrying case, UL-listed fuses, spare test gear in the hope that they’ll test leads, etc. get a day off work.” Physically, it’s 85 x 191 x 40mm and weighs in at “They’re’s also safety-shutterabout 450g. The meter is housed in what appears to be a ed so you can’t try to measure current when on any other tough ABS case (itself rated at 5.5kV insulation). settings and vice-versa.” The pack includes a set of quality shrouded probes and That sold us. We added some Yokogawa meters to the a 44-page manual which not only gives full operating inschool prize list! structions but also a detailed calibration procedure, if and OK, so let’s have a closer look at this quite remarkable when required. instrument: And the price? It’s a 5 -digit (50000 maximum reading) instrument with At $403 +GST (RRP), this is not a cheap meter. With the both digital and bargraph readouts and boasting a very quality, features, versatility and ruggedness it offers, you wide selection of automatic measurement functions. As you couldn’t expect it to be. But with that quality, features, would expect, these cover volts versatility and ruggedness, it’s and amps DC and AC (600V Cat III Contact: great value for money. and 1000V Cat II), and resistance. Yokogawa Australia Pty Ltd Put it this way: buy the Like many modern meters, it Tower A, 112-118 Talavera Road, Macquarie Park, NSW 2113 Yokogawa 734/02 and you’ll will also handle frequency (2Hz- Tel: (02) 8870-1100 Fax: (02) 9888-1844 probably never have to buy 99.9kHz ranges); temperature Website: www.yokogawa.com.au another DMM again! (RT) Final reminder: Central Coast Field Day is on this month Just in case you missed last month, here’s a reminder: the Central Coast Field Day, Australia’s largest Amateur Radio exhibition, is on again at the Wyong Race Course on Sunday, February 18th. There are always bargains to be had at the flea market where, along with individuals trad- 76  Silicon Chip ing their treasures, many suppliers unload excess stocks, samples and other goodies at prices you will never find in their retail stores. You can also view exhibits by amateur and communications clubs and groups with interests ranging from vintage radio through to satellite communications – and everything in between. Wyong Race Course is a one-hour drive north of Sydney (with a good train service too!) and gates open at 8.30am. If it’s anything like previous years, there will be a queue at the gate waiting to rush in and bag the best bargains! For more information contact (02) 4340 2500 or via their website, www.ccarc.org.au siliconchip.com.au 1000Ms/s USB scope from Wavecom The $1099 Velleman PCSU1000 from Wavecom is an innovative and space-saving portable 1000Ms/s Oscilloscope which plugs into your computer’s USB port. The stylish vertical design measures just 205 x 55 x 175mm. There is no need for external power (it’s also supplied by the USB port) and the software features zoom screens and long recording times for data logging. A DLL is supplied to Horn relays with fuses Now available from all Jaycar Electronics stores, resellers and online are these SPST horn relays with integral spade fuses. As well as for horns, they’re ideal for a wide range of automotive and other low voltage projects. Both have 12V coils and offer either 15A contacts (Cat SY4076 <at> $8.95) or 30A (Cat SY4077 <at> $12.95) contacts. allow you to create your own applications. It offers two input channels (with probes supplied) one external trigger, a bandwidth of DC to 60MHz (±3dB) and input coupling is either DC, AC or GND. With sampling at 1000Ms/s, the PCSU 1000 provides fast, accurate readings and measurements and suits most process applications and general electronics. Wavecom Instruments 275A Grange Rd, Findon, SA 5023 Tel: (08)8243 3500 Fax: (08) 8243 3501 Website: www.wavecom.com.au New ISM-band modules from TeleLink TeleLink Communications, agents in Australia for renowned Japanese company Circuit Design, Inc, will shortly have available the CDP-TX-02F-R transmitter and CDP-RX-02F-R receiver as upgrades of the CDP-02 series industrial use radio modules. Both are R&TTE and RoHS compliant. The CDP-02 series channel select- Contact: Jaycar Electronics PO Box 6424, Silverwater NSW 1811. Tel: 1800 022 888 Fax: (02) 9741 8500 Website: www.jaycar.com.au Projecting the right image With home theatre taking off in a huge way, ugly mounting brackets often detract from otherwise great systems. Just released is a range of projector mounts from Skunkworks, one of Australia’s leading flat screen mount manufacturers. The Fellini ‘M’ series projector mounts are designed for use in professional and high quality installations. They are used in many home theatres, boardrooms, conference centres, hotels and other areas where flexibility and aesthetics are a priority. They are light weight aluminium with exceptional tensile strength. A universal ‘X’ type flexible mounting head is fitted to a hexagonal-shaped base and a lever enables quick adjustment. There are three models: the compact Fellini 1391-M, which has a short pole measuring a neat 15cm and two models with poles that can be telescopically extended. The Fellini 1392-M has an extension range of 70 -130 cm and the Fellini 1393-M with an unusually long extension of 110 – 200cm. They all have a weight rating of 25kg and Contact: are highly flexible. The ‘M’ series enable the The Novita Group projector to be tilted 60° and rotated 360°. PO Box 1239, South Perth WA 6951 They are finished in a Euro-style silver sheen Tel: (08) 9313 4667 Fax: (08) 9313 4887 and are supplied with mounting hardware Website: www.skunkworks.com.au and accessories. siliconchip.com.au Contact: able TX and RX modules are used in the most popular 434MHz ISM band for short range devices. There are two types of the 128-channel model. One uses the DIP switches for changing channels, while the other is externally controlled through connector pins. Increasing the usable channels from 32 in the earlier model to 128 allows the operation of more nodes within the same area. They offer improved frequency temperature characteristics, from -20 to +60°C. RF output of TX complies with the European ISM band RF power limit and you can select between 10mW and 1mW. Selecting 1mW enables continuous transmission in all 128 channels. Contact: TeleLink Communications PO Box 5457, Nth Rockhampton, Qld 4702 Tel: (07) 4934 0413 Fax: (07) 4934 0311 Website: www.telelink.com.au STEPDOWN TRANSFORMERS 60VA to 3KVA encased toroids Harbuch Electronics Pty Ltd 9/40 Leighton Pl. HORNSBY 2077 Ph (02) 9476-5854 Fx (02) 9476-3231 February 2007  77 Off Ya Bike & Onto Ya... PICAXE! More words of wisdom from STAN SWAN Electronics is just as much about adaptation as it is invention. Here Stan takes a cheap bike computer and turns it into a digital amphour meter with the aid of his No.1 favourite chip, the mighty Picaxe! T he white-hot rate of change in technology may leave many gasping but one spin-off is that “leading edge” soon becomes “old hat”, often begging for enterprising use in other fields. Well, I’ve yet to see any MP3 players being used as audible fishing lures but it’s rapidly becoming “suck it and see” when it comes to persuading even last year’s hi-tech to work with “engines” such as the ever-appealing Picaxe family. I was reminded of this when overhearing a competitive mountain bike rider saying “Magnetic pickup bike computers are so 1990s. . .” His handlebars were so festooned with electronic devices, including a mapping GPS, that he looked more like a low-flying jumbo jet pilot. Probably even the average pedestrian now sports more computing power than the entire western world had 30 years ago and it is becoming increasingly 78  Silicon Chip common to see hikers with handheld GPS units as part of their portable electronics payload. But . . . bike computers? Although some are Hall effect or wireless, these traditionally used a magnet attached to a wheel spoke to trigger a fork-mounted reed switch as the wheel spun, with a display then showing, at least, speed (both peak and average) and distance travelled. The unit’s internal clock, following formulas such as speed = distance/ time, handles the basic calculation for you. No doubt others have pondered adapting these little gadgets in the past for windspeed, water flow, battery drain and the like but with recent attractively lowered prices (we’ve seen them for around $15) they now appeal for all manner of microcontroller work. Their even-cheaper pedestrian mate, the near ubiquitous pedometer, offers fewer display options but with today’s “10,000 daily steps for health” era, it won’t be long before they turn up in cornflakes packets. Prior to investigating these devices, it was considered that connection to a Picaxe would need replication of the magnetic make and break circuitry, along with possible de-bouncing and pulse shaping for reliable operation. All manner of classic switching techniques were pondered but to my delight it transpired that the hard work had already been done and that just standard Picaxe High/Pause/Low/ Pause generation was adequate. Ladies and gentlemen, it couldn’t be easier! Here’s sample code for an output at Picaxe-08M pin 4: Bikepedo: High 4 Pause 200 Low 4 Pause 200 Goto bikepedo siliconchip.com.au A solar cell charger being monitored with Stan’s Picaxe ammeter. You could also charge small SLA batteries (as shown at top) and even use one of Jaycar’s small wind generators (just visible top right of photo) instead of the solar cells. A paralleled red LED (with dropping resistor) allows visual pulse verification as well. Naturally the Pause value could be replaced with a b0, b1, etc variable (perhaps a DS18B20 style Readtemp b1?) that related to the condition being monitored. Direct Picaxe output pin connection looked dubious, so after some exploring with dropping resistors it was found that signals could be sensed siliconchip.com.au via just a 100nF capacitor. Usefully, this blocks any errant DC – it was noted several volts from the inbuilt battery were on the bike computer’s sensing leads. Pedometer After unscrewing and removing the small swinging magnet arm, a pair of wires can be simply soldered across the reed switch and run to the Picaxe driving circuit. The minimum pulse duration looked around a quarter of a second (250ms), which is consistent with a very brisk walk. Each time the Picaxe “high” transits “low” the pedometer counter advances by one. Hence with an upper display limit of 99,999 if an event provides a high/low transition every 10 seconds then 360 will occur hourly, and the counter can handle 99,999/360 = 277 hours worth (nearly 12 days). February 2007  79 CON2 DB9 2 22k 3 5 10k 1 2 3 7 IC1 PICAXE-08M 4 (TO PC SERIAL PORT) IO CHANNELS 0 6 1 5 2 8 PEDOMETER 00031 3 100nF 4 LED λ 330Ω The circuit for the simple Picaxe Pedometer adaptation, with a photo of the breadboard layout below. Connection to the Pedometer is simply across the internal reed switch, as shown at the bottom of the page. 80  Silicon Chip Cyclo (“bike”) computer 3--5V SUPPLY The bargain (but well thought of) Cat Eye Velo 1 bike computer simply had its magnetic pickup twin leads cut and inserted in the Picaxe circuit where the pedometer had previously been. Although wheel diameter can be adjusted, the unit was used straight out of the box. Incidentally, if you’re not familiar with the Velo 1, it’s from the Japanese firm CatEye, the worlds largest bike computer manufacturer (see www. cateye.com). Their products are available in most bike shops. I’ve not checked other bike computers but it’s possible that other brands might be just as easily adapted and driven. Cateye also have the Velo 5 which should be just as easily driven as the budget Velo 1. In fact the Velo 5 apparently reads to 300km/h which will even better suit Ah meter applications. The display, toggled to km/h, showed speeds inversely related to the High/Low pause length. Hence Pause 1000 (about as long as was possible before the displayed “zeroed”) equated to 3.6km/h stroll, while Pause 100 gave 36km/h, and Pause 40 (about the upper speed limit) showed 90km/h. Note this clearly meant the product of pause (ms) x speed (km/h) was 3600, so Pause 50 related to 72km/h and Pause 200 a slower 18km/h. These values may need calibrating in your own application of course, especially with a more involved program. It was naturally tempting to exploit the bike computer’s integration (summation over time) feature, particularly measuring a solar panel’s DC charging current in Amps as speed and accumulated amp-hours as distance (distance = speed x time of course). A range of monitoring techniques were explored (opto-coupling, thermal and Hall Effect, etc) but Picaxe–08M processing delays gave non linearity at higher currents (and thus shorter pauses), somewhat frustrating more elegant circuitry and time consuming on-board look-up tables. Hall-effect sensors, such as the Allegro UGN3503U, offer an attractive benefit in that they can monitor current both coming (+ve) or going(-ve) from a supply. There are extensive Halleffect, “Picaxable” insights at Glenn’s DIY wind site www.thebackshed.com A possible solution is to use TWO siliconchip.com.au Picaxes, with one doing the slow decision making and number crunching while the other (fed by a suitable Serout/Serin) handles the Pauses. Each Picaxe will need separate programming, so a very clear head will be in order. Don’t try this after a big day out celebrating the cricket wins! Amp and Amp-hour meter Frustration with more enhanced (and costly) current sensing techniques eventually lead to considering just measuring the voltage drop across a low value series resistor in the PV supply line. This classic technique, well known in automotive electrical work, exploits the fact that when currents are large (such as in a car with tens or even hundreds of Amps being drawn) a measurable voltage drop will develop across the very-low-resistance battery earthing strap. If, say, 10A passes through a .01W cable then Vacross= Ipassing x Rvalue = 10 x .01 = 0.1V = 100mV will be “dropped”. That’s a value now easily measured with a DMM (or Picaxe - see below). As this bike computer has an upper reading of 100km/h, user convenience should ideally give a direct readout of current so that “50” will mean 50mA is passing. If 12V solar panels are used this allows use of the abundant 12V 1W solar car battery trickle chargers, as even in very bright sun their output will be under 100mA. Furthermore, a 1W 1W series resistor being read as a shunt will easily handle the power and develop a bright sun maximum of Vacross = Ipassing x Rvalue = 0.1A x 1W = 100mV across it. Although the resistor is somewhat wasteful in series with the battery, most 12V solar (photovoltaic) cells deliver outputs up to 18V and therefore its effectwill be negligible. NB: larger panels will naturally deliver higher currents and this resistor should be suitably rated for the task, perhaps with a group in series parallel to present the right resistance but handle the higher currents. Ten 10W 1W resistors in parallel will present 1W but now handle 10W and be adequate for a larger 10W photovoltaic cell. Reading this mV-level voltage In contrast to the original Picaxe-08, which had only a 4-bit low-res ADC feature, the Picaxe-08M can read to siliconchip.com.au CON2 DB9 +4.5V 2 22k 3 10k 5 2 3 7 IC1 PICAXE-08M 4 (TO PC SERIAL PORT) IO CHANNELS 1 0 6 1 5 2 8 + RECHARGEABLE BATTERY – EG, 10x AA Nicad/ NiMH (12V) OR SMALL 12V SLA SMALL SOLAR PANEL OR WIND TURBINE GENERATOR 10kΩ 1Ω 1W 100nF 3 100nF 4 _ 1N4004 etc 12.34 LED λ LED ZENER + K A SC 2007 8 CAT EYE VELO 1 330Ω 4 1 BIKE COMPUTER Picaxe BIKE COMPUTER AMMETER Extending the idea of the Pedometer circuit on the facing page and using a popular Bike Computer we come up with this Picaxe Ammeter. A breadboard layout is shown below (note there are several differences between this and the photo overleaf). BIKE COMPUTER V+ SOLAR PANEL (+) 100nF 22kΩ A PICAXE08M LED K 4.5V (3x “AA” ALKALINE) * SOLAR PANEL (--) RECHARGEABLE BATTERY (+) K 10kΩ 330Ω 1N4004 10kΩ 0V * OR 4.8V (4x NiCd OR NiMH) 0 1 2 3 4 I/O CHANNELS 100nF 3 2 5 TO PC RS232 PORT (FOR PROGRAMMING) 10 bits as “word” (w) variables. With a 5V supply this means 210 = 1024 steps, allowing resolutions to 5V/1024 = ~ 5mV. Although the dropped voltages across our 1W resistor will be very low (pleasingly), this means the Picaxe-08M can read them directly under readadc10 and an otherwise traditional op amp circuit will not be needed. The downside to this simplicity however is that the display accuracy is influenced by the Picaxe supply voltage, although at 4.5V (3 x AA) it was found to be acceptably close to a series ammeter over a wide PV current range. In conjunction with a Zener regulator (3.3V was used here) higher Picaxe supply voltages showed 1Ω 1W RECHARGEABLE BATTERY (--) BIKE BIKE COMPUTER COMPUTER acceptable readings which actually improved as the batteries aged, but naturally a stable supply (perhaps using a 7805 for 5V) and software w2 tweaking should eliminate this drift. Calibration The charging of a wide variety of secondary batteries can be monitored by this set up, and since the sun (or wind) is an erratic energy source the “fuel gauge” will be particularly revealing of energy actually gathered over a period. Do you suspect your PV has seagulls perching on it some days? Dirt and leaves on the panel? Weather cloudy while you were elsewhere? This will tell you! Naturally, indoor (ie, mains-based) charging can enjoy a steady supply. February 2007  81 battery charging is rather a black art, as significant “wastage” arises with battery heating and self-discharge. The mAh rating on many Nicad & NiMH batteries is best viewed as indicative only – just because a NiMH “AA” cell is branded as 2500mAh it doesn’t mean this is sacred! Even if correct when new (!) it’ll decrease with age, storage and use. Traditionally, AA NiCd/NiMHs need to be over-filled anyway, with a 10-hour theoretical charge typically needing 14 hours to ensure full capacity. The winking LED used initially has been retained in this conversion, since it’s pulsing usefully shows the charging rate at a glance. Extension: Here’s a photo of the Picaxe/Bike Computer ammeter, albeit with a few components removed for simplicity. With 600mAh Nicad cells readily available from gutted solar garden lamps, it’s suggested that these be used in the test bed. However, small 12V SLAs could fit the bill – just keep in mind that larger batteries will take much longer to charge at low currents. Hence a 7Ah SLA may theoretically take 70 bright sun hours, meaning perhaps a fortnight or more with nonideal solar conditions. A 600mAh Nicad could be charged in a sunny day or two – a particularly attractive benefit for educators. A simple “known good” series ammeter in the PV supply line will allow verification of the bike computer’s reading as charging occurs. If display inconsistencies arise, perhaps due to an unusual solar PV or bike computer, then try altering pause w2 values to suit. It’s worth keeping in mind that 82  Silicon Chip This second circuit is again built on breadboard, following the now well established Picaxe-08M layout, since it still offers considerable scope for further investigation, perhaps as part of an educational project. Enthusiasts are advised to consider unified power supplies at least, since the bike computer “coin cell” will probably not last long if subject to extended use. The option switch built into the computer could probably also be brought out to a more convenient larger type. The Hall Effect approach mentioned earlier potentially offers a more versatile design of course, but this “1W” method is certainly cost effective and easy to get working! SC BIKEAMPH.BAS code listing (also downloadable at www.picaxe.orcon.net.nz/bikeamph.bas) ‘bikeamph.bas for Picaxe-08M driven ‘CATEYE Velo1’ bike computer conversion. ‘Suits educational output current monitoring of small 1W PV or wind gene ‘via simple 1W 1 Ohm supply shunt resistor, with voltage readadc10 measured. ‘Schematic (draft)=> www.picaxe.orcon.net.nz/bikeamph.gif -suits breadboard! ‘Initial solderless small PV layout =>www.picaxe.orcon.net.nz/bikeamph.jpg ‘Thanks to Glen’s A1 wind gene site => www.thebackshed.com for initial ideas ‘For ‘Silicon Chip’ article Feb. 2007. Via=> stan.swan<at>gmail.com 23/12/2006 shunt: readadc10 1, w1 ‘sertxd (#w1,13,10) if w1 <=1 then shunt ‘ approx w1 range 1 at 5mA to 30 at 100mA thru’ 1 Ohm ‘ useful w1 ‘F8’ check point-comment in/out as need be ‘ gives bike comp. zero reading on very low I (~<5mA) w2=600/w1 ‘ adjust top ‘600’for Picaxe supply calib. (600=~4.5V) high 4 pause w2 low 4 pause w2 ‘ Output pulse code for bike computer,fed to pin 4 ‘ via 100nF capacitor & parallel LED. Some scope for ‘ tweaking,but bike comp.times out if pause >~1000ms ‘ and upper detection range ~30mS (~100km/hr) goto shunt siliconchip.com.au SILICON CHIP Order Form/Tax Invoice Silicon Chip Publications Pty Ltd ABN 49 003 205 490 www.siliconchip.com.au PRICE GUIDE: SUBSCRIPTIONS YOUR DETAILS (Note: all subscription prices include P&P). 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Please feel free to visit the advertiser’s website: www.altronics.com.au Vintage Radio By RODNEY CHAMPNESS, VK3UG This view shows the Breville 801 prior to restoration. The “D” cell gives some idea of its size. The quirky Breville 801 personal portable Based on miniature 1.4V filament valves, compact portable radios such as the Breville 801 enjoyed a brief period of popularity during the late 1940s and early 1950s. Their performance was rather mediocre, however. S OME OF THE FIRST battery portables used a 2V wet cell and either two or three 45V batteries to power them. They were awkward, heavy sets and were ill-suited for portable use – not surprising considering that they were no more than adapted domestic home sets. 88  Silicon Chip However, the public was keen to really get “with it” in those halcyon days of radio development. Experimenters and manufacturers could see that there was a market for compact, portable receivers and they set about producing specialised designs. The advent of valves specifically de- signed for use with 1.5V dry batteries and 90V high-tension (HT) rails meant that the battery size and cost could be reduced. As a result, a new range of battery-powered portable radios appeared in the 1930s using octalbased valves, such as types 1P5GT, 1A7GT and 1D8GT. These sets were more convenient to transport, smaller and less costly to run than their predecessors. But that wasn’t the end of the improvements. At the end of World War II, the appearance of miniature 1.4V filament valves such as the 1T4, 1R5, 1S5, 3S4 and 3V4 meant that portable receivers could be made just that little bit smaller again. In addition, the intermediate frequency (IF) transformers were now more compact thanks to the use of improved ferrite materials and iron dust cores and shields. Batteries like the Eveready No.482 45V unit were also introduced around this time. This unit featured a layer method of construction for the individual 1.5V cells, resulting in a battery that was more compact than its predecessors. By the late 1940s, the manufacturers were producing portable 5-valve receivers that generally performed extremely well. However, the quest for “smaller is beautiful” led many manufacturers to design and build even smaller receivers. Two No.482 batteries were necessary for a 90V rail and although still reasonably compact, they were still too big for the “small is beautiful” brigade. This subsequently resulted in the development of the smaller No.467 67.5V battery, as the new miniature valves still worked quite well with a 67.5V HT rail. This meant that a single No.467 67.5V battery could now supply all the HT requirements of a dry battery receiver. The 1.5V battery used in the full-size portables was a No.745 which consisted of eight F-cells in siliconchip.com.au To operate the set, the shutter was moved away from the speaker and when the loudspeaker was fully exposed, the edge of the shutter closed two sets of contacts which applied power to the receiver’s filament and plate circuits. One of the accompanying photographs shows how this was done. The tuning and volume controls consist of two recessed knobs and these are turned by finger along their exposed edges. There is no likelihood of damage to the knobs due to the way they have been mounted. The batteries are easily replaced by removing two 3mm screws from the base of the set and then slipping off the bottom section of the case. The set was dismantled so that the cabinet could be repaired. Note the switch contacts on the shutter piece. parallel. It was reasoned that if the HT battery supply could be reduced in size, albeit with a reduced (but still useful) life, the same could be done with the 1.5V battery. This was achieved by using two “D” cells (No.950) in parallel. So that was the way manufacturers tapped into the “miniature” personal portable market in the late 1940s and early 1950s. The result was a range of quirky little four and 5-valve portable receivers that were popular with those on higher-than-average earnings. However, the popularity of these receivers waned fairly quickly. Basically, they suffered two serious limitations: (1) high battery consumption (and high replacement cost); and (2) unsatisfactory performance on anything other than local radio stations. In addition, these sets were usually subjected to a relatively hard life which meant that failures were common. And due to their compact construction, they were not easy to service. By contrast, full-size valve portables were a much better proposition when it came to receiving distant signals. They were also much easier to service and their larger batteries lasted much longer. Breville 801 receiver For its time, the Breville (1948) was siliconchip.com.au Circuit details probably the most compact of the Australian personal portables, the receiver measuring just 120 x 120 x 160mm (W x D x H). The case is a 2-piece Bakelite construction made by Marquis. The 75mm (3-inch) loudspeaker faces upwards and a roller type shutter, similar to that fitted to the writing bureaus of old, was slipped over it to protect the speaker when down at the beach. Fig.1 shows the circuit details of the Breville 801. It’s a fairly conventional superheterodyne receiver covering the range from 550-1500kHz. The front-end consists of a 1T4 RF stage, a 1R5 frequency converter and a 1T4 455kHz IF stage. A 1S5 is used as a combined detector, AGC diode and first audio amplifier, while a 3V4 acts as the second audio stage which then drives the loudspeaker. The RF stage is different to most valve portables of the era in that the antenna consists of an untuned loop This above-chassis view shows just how tightly the various parts are packed together, making the valves difficult to remove. February 2007  89 Above: the four oversize capacitors restricted access to other parts under the chassis. Right: this view shows the inductance tuning system used in the Breville 801. which doubles as a carrying strap. The output of this loop is coupled into the first tuned circuit. This tuned circuit is also different in that both it and the local oscillator (1R5) are inductance tuned. The coupling between the RF amplifier and the 1R5 frequency converter is aperiodic (ie, no tuned circuit). As shown, it uses an RF choke and a 20kW resistor as the load across which the RF signal is developed. This configuration saves using another tuned circuit at the expense of performance. In fact, the Philips 111 of 1948 uses a similar circuit to the Breville but it is designed to give a more even response across the broadcast band. The Philips 111 wasn’t a brilliant performer either! The frequency converter stage (1R5) is conventional and, as stated, uses inductance tuning rather than the more commonly used capacitance tuning. The IF amplifier has two double-tuned IF transformers and the 455kHz IF signal is amplified by the 1T4. As mentioned earlier, the detector and AGC diode is located in the 1S5. AGC is applied to the RF and IF stages but not to the converter. The audio from the detector is applied to the 1S5 pentode section and its output is then further amplified by the 3V4 audio output stage. Note that the screen of the 1S5 is fed via a voltage divider, although I’m not sure why the designers found this necessary. Bias of around -3.5V to -4V for the 3V4 is obtained from the voltage developed across a 350W resistor and 25mF capacitor. Cleaning up Unfortunately, the set featured here had had a hard life. The case was cracked at the top and a set of batteries that had been left in had leaked corrosive muck over quite a bit of the set. Initially, I sprayed the rusted terminals and metal work with Inox (WD40 could also be used) to soften the corrosion. I then used either used fine wet and dry paper or the blade of a screwdriver on the affected areas, periodically wiping away the loosened material with a cloth. Eventually, I was able to clean the set reasonably well but it still isn’t pristine. Part of the problem here is that the compact nature of the set restricts access to some areas. So the set isn’t as clean as I would have liked. Fixing the circuit This close-up shows the switch contacts at the end of the roller shutter. They close when the shutter is fully open. 90  Silicon Chip The next step was to get the set working. First, the valves were removed and a multimeter used to check that their filaments were intact. That done, I sprayed each valve socket with Inox and then replaced the valves. Once again, the compact nature of the set makes valve removal and replacement a difficult job. In fact, to remove the valves, I had to first wriggle them in their sockets to ease them out slightly and then siliconchip.com.au Fig.1: the Breville 801 employs a fairly conventional superheterodyne circuit based on miniature 1.4V filament valves. A single No.467 battery provided the 67.5V HT rail, while the filament voltage was provided by two “D” cells (No.950) in parallel. use a screwdriver to lever them out completely. The set had been worked on over the years and most of its original paper capacitors had been replaced with polyester types. However, the serviceman who did the work must only have had 630V units because that is what he fitted. They are bulky and made access almost impossible in some areas. The originals would have been 200V (and possibly 400V) types and would have been smaller. As a result, I removed all the 630V units and replaced them with 50V and 100V ceramic or polyester types which fitted in easily. The 8mF electrolytic capacitor across the HT rail was a 500V unit and I replaced this with a smaller 100V unit, which was much closer to the required rating. The 25mF electrolytic across the back-bias resistor was also changed. Although many parts were replaced with smaller equivalents to improve access, this wasn’t the only reason they were changed. Most were also changed in an effort to eliminate potential problems. However, one problem did eventuate, unfortunately – the AGC bypass capacitor had been incorrectly wired as well. Its earthy end is supsiliconchip.com.au posed to go to the chassis but it was connected to the screen of the 1T4 IF valve instead. Cabinet repairs Unfortunately, the top section of the Bakelite cabinet had broken along one edge and a piece had gone missing. Repairing this meant that the cabinet first had to be separated from the chassis. This simply involved removing the four screws that hold the chassis and the Bakelite top section together. Removing the top section of the cabinet also gives access to the speaker (which is an extremely tight fit into the case) and allows the slide shutter switch mechanism to be removed. The disassembled receiver can be seen in one of the accompanying photographs. With the set disassembled, the Bake­ lite top section could now be worked on. Back in July 2001, I described various methods for repairing Bakelite cabinets and I simply followed the techniques outlined in that article. First, I used 5-minute Araldite to glue the cracked section together. This wasn’t all that easy as the Bakelite had distorted over time, so keeping the two sides aligned proved to be rather difficult. Once the glue had set, I used a blunt file to smooth out the join in the cabinet. I then obtained a piece of thin plastic from a shirt box and securely taped and clamped it in position to form a mould for the fibreglass which I intended to use to replace the missing piece. Having secured the mold, some tinted fibreglass was poured into it and allowed to set. This was then followed with a second layer and this proved to be enough. The clamps were then removed and the fibreglass trimmed so that the cabinet now looked almost as good as new. Finally, the top section of the cabinet was re-attached to the chassis. Getting it going With the set still out of its cabinet, I powered it up via my dry-battery eliminator. But first I made sure that the filament voltage was set to 1.4V and the HT voltage to 67.5V. I was also careful not to transpose the connections – the filaments in these valves are very delicate and will not withstand having high voltages applied to them. As the set warmed up. I gradually adjusted the volume control to maximum only to be greeted by silence. I then turned the volume “down” but this time there was noise from the loudspeaker. The explanation is simFebruary 2007  91 The fully-restored receiver almost looks new, at least from the outside. Note the antenna wire wrapped around the strap. ple: the volume control markings on the cabinet are the wrong way around! Alternatively, the control could be rewired to make it work correctly. There was quite a bit of noise and it varied as I tuned across the broadcast band. The set appeared to be unstable, with audible whistles that varied in intensity and frequency as the set was tuned. What’s more, I couldn’t hear any stations. It was time for some troubleshooting, so I coupled my signal generator to the antenna strap and found I could force a signal through the set. I then decided to check the antenna strap for continuity. It proved to be open circuit but what was really strange was that both ends of the strap were earthed! There was no way the set could work like this. I also found that the antenna coil input winding went to a terminal that had nothing attached to it. Someone had certainly been busy with this set – it’s just a pity that they didn’t know what they were doing. Because the loop was open circuit I decided the best thing I could do was to loosely wind a piece of thin hook-up wire over the antenna strap and connect it into circuit the way it should have been connected. I’m not sure how the strap was originally made other than the fact that it uses “tinselled” wire. Whether it was woven as a flat strap or just used as a circular wire I don’t know (the set isn’t mine, so I didn’t feel inclined to cut into the strap). Some readers may not be familiar with tinselled wire. Headphones and similar items that required leads to be repeatedly flexed without breaking have this type of wire. Basically the centre of the cable consists of cotton (or similar) with a fine metal strip wound along it. It is difficult to solder so it is usually clamped to the termination point. With the new antenna wire in place, the set was now receiving a couple of stations but it was still oscillating in the RF stage. My suspicion was that the RF choke may have been coupling signal from the plate circuit back into the grid so I replaced it with a more compact unit. I also noticed that the 1T4’s grid lead was rather close to its plate lead. As a result, I replaced the existing grid lead with a longer piece of wire and dressed it well away from the plate circuit. I also decided to fit a tin plate shield around the 1R5 and earthed it alongside the valve to make the set more stable. These measures proved successful and the receiver is now stable in its operation. Alignment The set has no frequency markings on its simple dial scale, so I didn’t attempt to make sure it only tuned from 550kHz to 1500kHz (it actually tuned to 1550kHz at the high-frequency end of the dial). However, I did peak the Looking for real performance? NOT A REPRINT – Completely NEW projects – the result of two years research & development • • • • 160 PAGES 23 CHAPTE RS Fr om th e pu bli sh Learn how engine management systems work Build projects to control nitrous, fuel injection and turbo boost systems Switch devices on and off on the basis of signal frequency, temperature and voltage Build test instruments to check fuel injector duty cycle, fuel mixture and brake and coolant temperatures Mail order prices: Aust. $A22.50 (incl. GST & P&P); Overseas $A26.00 via airmail. Order by phoning (02) 9939 3295 & quoting your credit card number; or fax the details to (02) 9939 2648; or mail your order with cheque or credit card details to Silicon Chip Publications, PO Box 139, Collaroy, NSW 2097. 92  Silicon Chip er s of Intellig I SBN 9 780 9 $19.80 (inc turbo tient mer 095 852 294 - 4 58 5 229 GST) 46 NZ $22.00 (inc GST) TURBO & nitrou BOOST s fuel cont rollers How en g managemine ent work s siliconchip.com.au Photo Gallery: STC A141 Bantam (1947) Introducing the new and exciting range of Hot Devil Soldering Irons and Gas Torches BONUS PACK 2 FOR 1 UNDER $36.00 R.R.P. RELEASED BY STANDARD TELEPHONES & CABLES PTY LTD in 1947, the Bantam A141 was a miniature 4-valve superhet that measured just 230mm wide by 150mm high. In fact, it was so compact that it was necessary to remove the chassis in order to replace the 6AG6 output valve! The mottled green cabinet example illustrated here is uncommon. The valve line-up was as follows: 6K8-G frequency changer; 6G8-G IF amplifier/detector/AVC rectifier; 6AG6 audio output; and 6X5-GT rectifier. Photo: Historical Radio Society of Australia, Inc. tuning of the antenna coil at around 1400kHz by adjusting the trimmer across this coil. That done, the IF adjustments were checked and they all appeared to be correctly tuned, so I left it at that. Summary In operation, this receiver is rather noisy when tuned to a station, as the signal pick-up is not good with the antenna system used. However, the performance may have been better when the original loop antenna was still in good order. Some of the lead and component layout also leaves a bit to be desired and can cause instability in the RF stages (hence the need for modifications). The coupling between the RF and converter stages is also inefficient, resulting in less sensitivity than otherwise. The IF and audio stages are conventional and these parts of the receiver work quite well. Another problem with this set is siliconchip.com.au that it is difficult to work on, due to its compact design. In fact, the layout and construction is rather amateurish in many ways. That said, the controls are easy to use and they are well-protected against damage. The dial scale is nothing more than a 0-120 designation, rather like the sets from the 1920s. It probably doesn’t matter as the set won’t receive many stations anyway. In the end, these little miniature four and 5-valve sets from the 1940s and 1950s enjoyed a very short period of popularity and then only in areas of high signal strength. Like almost all sets of this type, the performance of Breville 801 is mediocre to say the least and the battery life is short. Would I have bought one of these sets when they were new? I doubt it. However, it is a good example of a type of set that deservedly only enjoyed a short period of fame and for that reason alone it is worthy of restoration SC and display. Temp to 1300 oC Supplied with Bonus Pocket Torch valued at $12.95 R.R.P. Model No. MT6000SB MICRO TORCH The smallest ever Butane Gas MicroTorch and Soldering Iron with Auto Ignition UNDER $25.00 R.R.P. Model No. PT16TS GAS TRIGGER TORCH & SOLDERING IRON o Soldering up to 400 C Torch to 1300 oC o Hot Blow to 500 C Anti-Flare Wind Resistant R.R.P. Free Standing Auto Ignition UNDER $59.00 Model No. HT882 For your nearest stockist visit: www.hotdevil.com.au or phone: (03) 9775 0713 February 2007  93 Silicon Chip Back Issues 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. 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. Railways, Pt.1; Keypad Combination Lock; Jacob’s Ladder Display. October 1995: 3-Way Loudspeaker System; Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.2; Nicad Fast Charger. May 1998: 3-LED Logic Probe; Garage Door Opener, Pt.2; Command Control System, Pt.4; 40V 8A Adjustable Power Supply, Pt.2. November 1995: Mixture Display For Fuel Injected Cars; CB Trans­verter For The 80M Amateur Band, Pt.1; PIR Movement Detector. 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. 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. April 1994: Sound & Lights For Model Railway Level Crossings; Dual Supply Voltage Regulator; Universal Stereo Preamplifier; Digital Water Tank Gauge; Engine Management, Pt.7. May 1996: High Voltage Insulation Tester; Knightrider LED Chaser; Simple Intercom Uses Optical Cable; Cathode Ray Oscilloscopes, Pt.3. 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. February 1998: Telephone Exchange Simulator For Testing; Command Control For Model Railways, Pt.2; 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; Understanding Electric Lighting; Pt.6. 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 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. January 1998: 4-Channel 12VDC or 12VAC Lightshow, Pt.1; Command Control For Model Railways, Pt.1; Pan Controller For CCD Cameras. 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. June 1996: Stereo Simulator (uses delay chip); Rope Light Chaser; Low Ohms Tester For Your DMM; Automatic 10A Battery Charger. 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. July 1996: VGA Digital Oscilloscope, Pt.1; Remote Control Extender For VCRs; 2A SLA Battery Charger; 3-Band Parametric Equaliser;. 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. 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; HF Amateur Radio Receiver; Cathode Ray Oscilloscopes, Pt.5. 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. 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. 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. 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. September 1994: Automatic Discharger For Nicad Batteries; MiniVox Voice Operated Relay; AM Radio For Weather Beacons; Dual Diversity Tuner For FM Mics, Pt.2; Electronic Engine Management, Pt.12. 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. January 1999: High-Voltage Megohm Tester; A Look At The BASIC Stamp; Bargraph Ammeter For Cars; Keypad Engine Immobiliser. 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. 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. November 1994: Dry Cell Battery Rejuvenator; Novel Alphanumeric Clock; 80-M DSB Amateur Transmitter; 2-Cell Nicad Discharger. January 1997: Control Panel For Multiple Smoke Alarms, Pt.1; Build A Pink Noise Source; Computer Controlled Dual Power Supply, Pt.1; Digi-Temp Thermometer (Monitors Eight Temperatures). 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. 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. January 1995: Sun Tracker For Solar Panels; Battery Saver For Torches; Dual Channel UHF Remote Control; Stereo Microphone Pre­amp­lifier. February 1995: 2 x 50W Stereo Amplifier Module; Digital Effects Unit For Musicians; 6-Channel LCD Thermometer; Wide Range Electrostatic Loudspeakers, Pt.1; Remote Control System For Models, Pt.2. 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. 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. 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. 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. March 1999: Build A Digital Anemometer; DIY PIC Programmer; Build An Audio Compressor; Build A 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; Carbon Monoxide Alarm. 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. 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. March 1997: 175W PA Amplifier; Signalling & Lighting For Model Railways; Jumbo LED Clock; Cathode Ray Oscilloscopes, Pt.7. 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. 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. 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. 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. 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. 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. 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. 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. 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. October 1997: 5-Digit Tachometer; Central Locking For Your Car; PCControlled 6-Channel Voltmeter; 500W Audio Power Amplifier, Pt.3. 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. 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. 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. August 1995: Fuel Injector Monitor For Cars; A Gain Controlled Microphone Preamp; Identifying IDE Hard Disk Drive Parameters. December 1997: Build A 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. September 1995: Railpower Mk.2 Walkaround Throttle For Model ORDER FORM January 2000: Spring Reverberation Module; An Audio-Video Test Generator; Parallel Port Interface Card; Telephone Off-Hook Indicator. February 2000: Multi-Sector Sprinkler Controller; A Digital Voltmeter For Your Car; Safety Switch Checker; Sine/Square Wave Oscillator. Please send the following back issues:________________________________________ Enclosed is my cheque/money order for $­______or please debit my: o Bankcard o Visa Card o Master Card Card No. Signature ___________________________    Card expiry date_____ /______ Name _____________________________    Phone No (___) ____________ PLEASE PRINT Street _________________________ Suburb/town ____________________ Postcode ________ Email Address _________________________________ 94  Silicon Chip 10% OF SUBSCR F TO IB OR IF Y ERS OU 10 OR M BUY ORE Note: prices include postage & packing Australia ............................... $A9.50 (incl. GST) Overseas (airmail) ..................................... $A13 Detach and mail to: Silicon Chip Publications, PO Box 139, Collaroy, NSW, Australia 2097. Or call (02) 9939 3295 & quote your credit card details; or fax the details to (02) 9939 2648. Email: silicon<at>siliconchip.com.au siliconchip.com.au March 2000: Resurrecting An Old Computer; 100W Amplifier Module, Pt.1; Electronic Wind Vane With 16-LED Display; Glowplug Driver. Amplifier Module, Pt.1; Gear Indicator For Cars; Active 3-Way Crossover For Speakers; Using Linux To Share An Optus Cable Modem, Pt.3. A MIDI Theremin, Pt.1; Bass Extender For Hifi Systems; Sports Scoreboard, Pt.2; SMS Controller Add-Ons; A $5 Variable Power Supply. May 2000: Ultra-LD Stereo Amplifier, Pt.2; LED Dice (With PIC Microcontroller); 50A Motor Speed Controller For Models. February 2003: PortaPal PA System, Pt.1; 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. May 2005: Getting Into Wi-Fi, Pt.1; Build A 45-Second Voice Recorder; Wireless Microphone/Audio Link; MIDI Theremin, Pt.2; Sports Scoreboard, Pt.3; Automatic Stopwatch Timer. March 2003: LED Lighting For Your Car; Peltier-Effect Tinnie Cooler; PortaPal PA System, Pt.2; 12V SLA Battery Float Charger; Little Dynamite Subwoofer; Fun With The PICAXE, Pt.2 (Shop Door Minder). June 2005: Wi-Fi, Pt.2; The Mesmeriser LED Clock; Coolmaster Fridge/ Freezer Temperature Controller; Alternative Power Regular; PICAXE Colour Recognition System; AVR200 Single Board Computer, Pt.1. August 2000: Theremin; Spinner (writes messages in “thin-air”); Proximity Switch; Structured Cabling For Computer Networks. April 2003: Video-Audio Booster For Home Theatre Systems; Telephone Dialler For Burglar Alarms; Three PIC Programmer Kits; PICAXE, Pt.3 (Heartbeat Simulator); Electric Shutter Release For Cameras. 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. May 2003: Widgybox Guitar Distortion Effects Unit; 10MHz Direct Digital Synthesis Generator; Big Blaster Subwoofer; Printer Port Simulator; PICAXE, Pt.4 (Motor Controller). July 2005: Getting Into Wi-Fi, Pt.3; Remote-Controlled Automatic Lamp Dimmer; Lead-Acid Battery Zapper; Serial Stepper Motor Controller; AVR200 Single Board Computer, Pt.2; Salvaging & Using Thermostats; Unwired Modems & External Antennas; PICAXE in Schools, Pt.3. October 2000: Guitar Jammer; Breath Tester; Wand-Mounted Inspection Camera; Subwoofer For Cars; Fuel Mixture Display, Pt.2. 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. June 2000: Automatic Rain Gauge; Parallel Port VHF FM Receiver; Switchmode Power Supply (1.23V to 40V) Pt.1; CD Compressor. July 2000: Moving Message Display; Compact Fluorescent Lamp Driver; Musicians’ Lead Tester; Switchmode Power Supply, Pt.2. 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. 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. 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. 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; 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. 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. 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. December 2005: Good Quality Car Sound On The Cheap; Pt.2; Building The Ultimate Jukebox, Pt.1; Universal High-Energy Ignition System, Pt.1; Remote LED Annunciator For Queue Control; Build A MIDI Drum Kit, Pt.2; 433MHz Wireless Data Communication. 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. 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. 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. 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. 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 High-Power Audio-Video Link; Touch And/Or Remote-Controlled Light Dimmer, Pt.2; Booting A PC Without A Keyboard; 4-Way Event Timer. March 2002: Mighty Midget Audio Amplifier Module; 6-Channel IR Remote Volume Control, Pt.1; RIAA Pre­-­Amplifier For Magnetic Cartridges; 12/24V Intelligent Solar Power Battery Charger. 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. 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. August 2002: Digital Instrumentation Software For PCs; Digital Storage Logic Probe; Digital Therm./Thermostat; Sound Card Interface For PC Test Instruments; Direct Conversion Receiver For Radio Amateurs. September 2002: 12V Fluorescent Lamp Inverter; 8-Channel Infrared Remote Control; 50-Watt DC Electronic Load; Spyware – An Update. February 2004: PC Board Design, Pt.1; Supply Rail Monitor For PCs; Studio 350W Power Amplifier Module, Pt.2; Shorted Turns Tester For Line Output Transformers; PICAXE-18X 4-Channel Datalogger, Pt.2. March 2004: PC Board Design, Pt.2; Build The QuickBrake For Increased Driving Safety; 3V-9V (or more) DC-DC Converter; ESR Meter Mk.2, Pt.1; PICAXE-18X 4-Channel Datalogger, Pt.3. April 2004: PC Board Design, Pt.3; Loudspeaker Level Meter For Home Theatre Systems; Dog Silencer; Mixture Display For Cars; ESR Meter Mk.2, Pt.2; PC/PICAXE Interface For UHF Remote Control. May 2004: Amplifier Testing Without High-Tech Gear; Component Video To RGB Converter; Starpower Switching Supply For Luxeon Star LEDs; Wireless Parallel Port; Poor Man’s Metal Locator. January 2006: Pocket TENS Unit For Pain Relief; “Little Jim” AM Radio Transmitter; Universal High-Energy Ignition System, Pt.2; Building The Ultimate Jukebox, Pt.2; MIDI Drum Kit, Pt.3; Picaxe-Based 433MHz Wireless Thermometer; A Human-Powered LED Torch. February 2006: Electric-Powered Model Aircraft, Pt.1; Do-It-Yourself Electronic Servicing; PC-Controlled Burglar Alarm System, Pt.1; Build A Charger For iPods & MP3 Players; Picaxe-Powered Thermostat & Temperature Display; Build A MIDI Drum Kit, Pt.4; Building The Ultimate Jukebox, Pt.3. March 2006: The Electronic Camera, Pt.1; PC-Controlled Burglar Alarm System, Pt.2; Low-Cost Intercooler Water Spray Controller; AVR ISP SocketBoard; Phone/Fax Missed Call Alert; Build A Low-Cost Large Display Anemometer. April 2006: The Electronic Camera, Pt.2; Studio Series Remote Control Module (For A Stereo Preamplifier); 4-Channel Audio/Video Selector; Universal High-Energy LED Lighting System, Pt.1; Picaxe Goes Wireless, Pt.1 (Using the 2.4GHz XBee Modules). May 2006: Lead-Acid Battery Zapper & Condition Checker; Universal High-Energy LED Lighting System, Pt.2; Passive Direct Injection (DI) Box For Musicians; Remote Mains Relay Box; Vehicle Voltage Monitor; Picaxe Goes Wireless, Pt.2; Boost Your XBee’s Range Using Simple Antennas; Improving The Sound Of Salvaged Loudspeaker Systems. June 2006: Television – The Elusive Goal, Pt.1; Electric-Powered Model Aircraft, Pt.2; Pocket A/V Test Pattern Generator; Two-Way SPDIF-toToslink Digital Audio Converter; Build A 2.4GHz Wireless A/V Link; A High-Current Battery Charger For Almost Nothing. June 2004: Dr Video Mk.2 Video Stabiliser; Build An RFID Security Module; Fridge-Door Alarm; Courtesy Light Delay For Cars; Automating PC Power-Up; Upgraded Software For The EPROM Programmer. July 2006: Television – The Elusive Goal, Pt.2; Mini Theremin Mk.2, Pt.1; Programmable Analog On-Off Controller; Studio Series Stereo Preamplifier; PC-Controlled Mains Switch, Mk.2; Stop Those Zaps From Double-Insulated Equipment. July 2004: Silencing A Noisy PC; Versatile Battery Protector; Appliance Energy Meter, Pt.1; A Poor Man’s Q Meter; Regulated High-Voltage Supply For Valve Amplifiers; Remote Control For A Model Train Layout. August 2006: Video Projector Survey; Television – The Elusive Goal, Pt.3; Novel Picaxe-Based LED Chaser Clock; Build A Magnetic Cartridge Preamplifier; An Ultrasonic Eavesdropper; Multi-Throttle Control For PC Flight Simulators; Mini Theremin Mk.2, Pt.2. August 2004: Video Formats: Why Bother?; VAF’s New DC-X Generation IV Loudspeakers; Video Enhancer & Y/C Separator; Balanced Microphone Preamp; Appliance Energy Meter, Pt.2; 3-State Logic Probe. September 2004: Voice Over IP (VoIP) For Beginners; WiFry – Cooking Up 2.4GHz Antennas; Bed Wetting Alert; Build a Programmable Robot; Another CFL Inverter. October 2004: The Humble “Trannie” Turns 50; SMS Controller, Pt.1; RGB To Component Video Converter; USB Power Injector; Remote Controller For Garage Doors & Gates. November 2004: 42V Car Electrical Systems; USB-Controlled Power Switch (Errata Dec. 2004); Charger For Deep-Cycle 12V Batteries, Pt.1; Driveway Sentry; SMS Controller, Pt.2; PICAXE IR Remote Control. December 2004: Build A Windmill Generator, Pt.1; 20W Amplifier Module; Charger For Deep-Cycle 12V Batteries, Pt.2; Solar-Powered Wireless Weather Station; Bidirectional Motor Speed Controller. October 2002: Speed Controller For Universal Motors; PC Parallel Port Wizard; Cable Tracer; AVR ISP Serial Programmer; 3D TV. January 2005: Windmill Generator, Pt.2; Build A V8 Doorbell; IR Remote Control Checker; 4-Minute Shower Timer; The Prawnlite; Sinom Says Game; VAF DC-7 Generation 4 Kit Speakers. 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. February 2005: Windmill Generator, Pt.3; USB-Controlled Electrocardiograph; TwinTen Stereo Amplifier; Inductance & Q-Factor Meter, Pt.1; A Yagi Antenna For UHF CB; $2 Battery Charger. 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. March 2005: Windmill Generator, Pt.4; Sports Scoreboard, Pt.1; Swimming Pool Lap Counter; Inductance & Q-Factor Meter, Pt.2; Shielded Loop Antenna For AM; Cheap UV EPROM Eraser; Sending Picaxe Data Over 477MHz UHF CB; $10 Lathe & Drill Press Tachometer. January 2003: Receiving TV From Satellites, Pt 2; SC480 50W RMS April 2005: Install Your Own In-Car Video (Reversing Monitor); Build siliconchip.com.au October 2005: A Look At Google Earth; Dead Simple USB Breakout Box; Studio Series Stereo Preamplifier, Pt.1; Video Reading Aid For Vision Impaired People; Simple Alcohol Level Meter; Ceiling Fan Timer. November 2005: Good Quality Car Sound On The Cheap; Pt.1; Microbric – Robotics For Everyone; PICAXE In Schools, Pt.5; Studio Series Stereo Headphone Amplifier; Build A MIDI Drum Kit, Pt.1; Serial I/O Controller & Analog Sampler; Delta XL02 Tower Loudspeaker System. 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. 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. September 2005: Build Your Own Seismograph; Bilge Sniffer For Boats; VoIP Analog Phone Adaptor; Mudlark A205 Valve Stereo Amplifier, Pt.2; PICAXE in Schools, Pt.4. 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. December 2003: How To Receive Weather Satellite Images; SelfDiagnostics Plug For Cars; PC Board Design, Pt.3; VHF Receiver For Weather Satellites; Linear Supply For Luxeon 1W Star LEDs; 5V Meter Calibration Standard; PIC-Based Car Battery Monitor; PICAXE Pt.10. 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. August 2005: Mudlark A205 Valve Stereo Amplifier, Pt.1; Programmable Flexitimer; Carbon Monoxide Alert; Serial LCD Driver; Enhanced Sports Scoreboard; Salvaging Washing Maching Pressure Switches. September 2006: Thomas Alva Edison – Genius, Pt.1; Transferring Your LPs To CDs & MP3s; Turn an Old Xbox Into A $200 Multimedia Player; Picaxe Net Server, Pt.1; Build The Galactic Voice; Aquarium Temperature Alarm; S-Video To Composite Video Converter. October 2006: Thomas Alva Edison – Genius, Pt.2; Review – The CarChip E/X (Logs All Sorts Of Data); LED Tachometer With Dual Displays, Pt.1; UHF Prescaler For Frequency Counters; Infrared Remote Control Extender; Picaxe Net Server, Pt.2; Easy-To-Build 12V Digital Timer Module; Build A Super Bicycle Light Alternator. November 2006: Sony Alpha A100 Digital SLR Camera (Review); Build A Radar Speed Gun, Pt.1; Build Your Own Compact Bass Reflex Loudspeakers; Programmable Christmas Star; DC Relay Switch; LED Tachometer With Dual Displays, Pt.2; Picaxe Net Server, Pt.3. December 2006: Bringing A Dead Cordless Drill Back To Life; Cordless Power Tool Charger Controller; Build A Radar Speed Gun, Pt.2; Heartbeat CPR Training Beeper; Super Speedo Corrector; 12/24V Auxiliary Battery Controller; Picaxe Net Server, Pt.3. January 2007: Versatile Temperature Switch; Intelligent Car AirConditioning Controller; Remote Telltale For Garage Doors; Intelligent 12V Charger For SLA & Lead-Acid Batteries. PLEASE NOTE: issues not listed have sold out. All other issues are in stock. We can supply photostat copies of articles from sold-out issues for $A9.50 each within Australia or $A13.00 each overseas (prices include 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 February 2007  95 ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. PRACTICAL RF HANDBOOK AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* Alternative fuel expert Carl Vogel gives you a hands-on guide with A guide to RF design for engineers, technicians, students and enthusiasts. the latest technical information and easy-to-follow instructions Covers key topics in RF: analog design principles, transmission lines, for building a two-wheeled electric vehicle – from a streamlined couplers, transformers, amplifiers, oscillators, modulation, transmitters and scooter to a full-sized motorcycle. 384 pages in soft cover. receivers, propagation and antennas. 279 pages in paperback. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST ALL S ILICON C HIP SUBSCRIBERS – PRINT, OR BOTH – AUTOMATICALLY QUALIFY FOR A REFERENCE $ave 10%ONLINE DISCOUNT ON ALL BOOK OR PARTSHOP PURCHASES. CHIP BOOKSHOP 10% (Does not apply to subscriptions) SILICON For the latest titles and information, please refer to our website books page: www.siliconchip.com.au/Shop/Books PIC MICROCONTROLLERS: know it all SELF ON AUDIO Multiple authors $85.00 The best of subjects Newnes authors have written over the past few years, combined in a one-stop maxi reference. Covers introduction to PICs and their programming in Assembly, PICBASIC, MBASIC & C. 900+ pages. PROGRAMMING and CUSTOMIZING THE PICAXE By David Lincoln (2nd Ed, 2011) $65.00* A great aid when wrestling with applications for the PICAXE See series of microcontrollers, at beginner, intermediate and Review April advanced levels. Every electronics class, school and library should have a copy, along with anyone who works with PICAXEs. 300 pages in paperback. 2011 PIC IN PRACTICE by D W Smith. 2nd Edition - published 2006 $60.00* Based on popular short courses on the PIC, for professionals, students and teachers. Can be used at a variety of levels. An ideal introduction to the world of microcontrollers. 255 pages in paperback. PIC MICROCONTROLLER – your personal introductory course By John Morton 3rd edition 2005. $60.00* A unique and practical guide to getting up and running with the PIC. It assumes no knowledge of microcontrollers – ideal introduction for students, teachers, technicians and electronics enthusiasts. Revised 3rd edition focuses entirely on re-programmable flash PICs such as 16F54, 16F84 12F508 and 12F675. 226 pages in paperback. by Douglas Self 2nd Edition 2006 $69.00* A collection of 35 classic magazine articles offering a dependable methodology for designing audio power amplifiers to improve performance at every point without significantly increasing cost. Includes compressors/limiters, hybrid bipolar/FET amps, electronic switching and more. 467 pages in paperback. SMALL SIGNAL AUDIO DESIGN By Douglas Self – First Edition 2010 $95.00* The latest from the Guru of audio. Explains audio concepts in easy-to-understand language with plenty of examples and reasoning. Inspiration for audio designers, superb background for audio enthusiasts and especially where it comes to component peculiarities and limitations. Expensive? Yes. Value for money? YES! Highly recommended. 558 pages in paperback. AUDIO POWER AMPLIFIER DESIGN HANDBOOK by Douglas Self – 5th Edition 2009 $85.00* "The Bible" on audio power amplifiers. Many revisions and updates to the previous edition and now has an extra three chapters covering Class XD, Power Amp Input Systems and Input Processing and Auxiliarly Subsystems. Not cheap and not a book for the beginner but if you want the best reference on Audio Power Amps, you want this one! 463 pages in paperback. DVD PLAYERS AND DRIVES by K.F. Ibrahim. Published 2003. $71.00* OP AMPS FOR EVERYONE By Bruce Carter – 4th Edition 2013 $83.00* This is the bible for anyone designing op amp circuits and you don't have to be an engineer to get the most out of it. It is written in simple language but gives lots of in-depth info, bridging the gap between the theoretical and the practical. 281 pages, A guide to DVD technology and applications, with particular focus on design issues and pitfalls, maintenance and repair. Ideal for engineers, technicians, students of consumer electronics and sales and installation staff. 319 pages in paperback. by Sanjaya Maniktala, Published April 2012. $83.00 Thoroughly revised! The most comprehensive study available of theoretical and practical aspects of controlling and measuring EMI in switching power supplies. Subtitled Exploring the PIC32, a Microchip insider tells all on this powerful PIC! Focuses on examples and exercises that show how to solve common, real-world design problems quickly. Includes handy checklists. FREE CD-ROM includes source code in C, the Microchip C30 compiler, and MPLAB SIM. 400 pages paperback. By Garry Cratt – Latest (7th) Edition 2008 $49.00 Written in Australia, for Australian conditions by one of Australia's foremost satellite TV experts. If there is anything you wanted to know about setting up a satellite TV system, (including what you can't do!) it's sure to be covered in this 176-page paperback book. See Review Feb 2004 SWITCHING POWER SUPPLIES A-Z PROGRAMMING 32-bit MICROCONTROLLERS IN C By Luci di Jasio (2008) $79.00* PRACTICAL GUIDE TO SATELLITE TV See Review March 2010 ELECTRIC MOTORS AND DRIVES By Austin Hughes & Bill Drury - 4th edition 2013 $59.00* This is a very easy to read book with very little mathematics or formulas. It covers the basics of all the main motor types, DC permanent magnet and wound field, AC induction and steppers and gives a very good description of how speed control circuits work with these motors. Soft covers, 444 pages. NEWNES GUIDE TO TV & VIDEO TECHNOLOGY By KF Ibrahim 4th Edition (Published 2007) $49.00 It's back! Provides a full and comprehensive coverage of video and television technology including HDTV and DVD. Starts with fundamentals so is ideal for students but covers in-depth technologies such as Blu-ray, DLP, Digital TV, etc so is also perfect for engineers. 600+ pages in paperback. RF CIRCUIT DESIGN by Chris Bowick, Second Edition, 2008. $63.00* The classic RF circuit design book. RF circuit design is now more important that ever in the wireless world. In most of the wireless devices that we use there is an RF component – this book tells how to design and integrate in a very practical fashion. 244 pages in paperback. PRACTICAL RF HANDBOOK AC MACHINES By Jim Lowe Published 2006 $66.00* Applicable to Australian trades-level courses including NE10 AC Machines, NE12 Synchronous Machines and the AC part of NE30 Electric Motor Control and Protection. Covering polyphase induction motors, singlephase motors, synchronous machines and polyphase motor starting. 160 pages in paperback. PRACTICAL VARIABLE SPEED DRIVES & POWER ELECTRONICS Se e by Malcolm Barnes. 1st Ed, Feb 2003. $73.00* Review An essential reference for engineers and anyone who wishes to design or use variable speed drives for induction motors. 286 pages in soft cover. Feb 2003 BUILD YOUR OWN ELECTRIC MOTORCYCLE by Carl Vogel. Published 2009. $40.00* by Ian Hickman. 4th edition 2007 $61.00* Alternative fuel expert Carl Vogel gives you a hands-on guide with A guide to RF design for engineers, technicians, students and enthusiasts. the latest technical information and easy-to-follow instructions Covers key topics in RF: analog design principles, transmission lines, for building a two-wheeled electric vehicle – from a streamlined couplers, transformers, amplifiers, oscillators, modulation, transmitters and scooter to a full-sized motorcycle. 384 pages in soft cover. receivers, propagation and antennas. 279 pages in paperback. *NOTE: ALL PRICES ARE PLUS P&P – AUSTRALIA ONLY: $10.00 per order; NZ – $AU12.00 PER BOOK; REST OF WORLD $AU18.00 PER BOOK To Place Your Order: INTERNET (24/7) PAYPAL (24/7) eMAIL (24/7) www.siliconchip. com.au/Shop/Books Use your PayPal account silicon<at>siliconchip.com.au silicon<at>siliconchip.com.au with order & credit card details FAX (24/7) MAIL (24/7) Your order and card details to Your order to PO Box 139 Collaroy NSW 2097 (02) 9939 2648 with all details PHONE – (9-5, Mon-Fri) Call (02) 9939 3295 with with order & credit card details You can also order and pay for books by cheque/money order (Mail Only). Make cheques payable to Silicon Chip Publications. ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST 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 Increased load current rating Regarding the “Versatile Electronic Load” in “Circuit Notebook” in the March 2006 issue, how can I make a 100mH inductor (L1 in the circuit) to take as much as 17A current? (G. C., Ballarat, Vic). • First up, the circuit is not capable of sinking 17A without major modifications. Increasing the power handling capability while maintaining reliability may prove to be a difficult proposition. Multiple Mosfets in parallel with the existing device will increase power handling but it is not easy to get the devices to share the load equally. If you want to experiment with paralleled devices, Mosfets specified for audio power amplifiers might be the best option. These are designed for use in their linear regions, so are likely to work better in this application. In use, check the temperature of each device using an infrared thermometer or thermocouple to determine load sharing. You could also use a single, larger Mosfet (such as a “DICE” packaged device). Regarding the 100mH inductor, you’ll probably need to customwind your own unit. Suitably large “Amidon” iron-powder toroids are available locally from RJ & US Imports (http://users.catchnet.com. au/~rjandusimports/index.html) and Rockby Electronics (www.rockby. com.au) Connecting a cassette player to a computer I have quite a few audio cassette tapes which are now longer available or have irreplaceable voices of family members no longer with us, that I would like to transfer to CD. Unfortunately I no longer have a cassette deck and suitable secondhand units at Cash Converters are still at the hundreddollar mark. I have looked at the headphone socket on my portable stereo but this, I believe, is unsuitable for the audio input on my computer. What do I need to do so I can use the headphone socket on my portable stereo? I’m sure I’m not the only person with irreplaceable audio cassettes decaying in a drawer; perhaps you could make it a project. Maybe you could make it a unit that would take the audio from the headphone socket, clean the tape noise, maybe even convert it from analog to digital (though my TV card already does that) and then take it to the “Audio In” on a computer. If the headphone socket is non-optimum, perhaps you could design it to take the signal directly from the heads? (J. W., via email). • Your headphone outputs should drive your computer’s audio input without problems but you may need to load each of the outputs with a 32W resistor to ensure that the headphone stages work correctly. Making labels for SILICON CHIP projects I am building some projects from SILICON CHIP and would like to print my own panel labels. Would you know which PC software would be best for this? (C. W., Werris Creek, NSW). • The quickest and easiest way to produce front-panel labels for our projects is to make use of the original artwork published in the magazine or posted on our website. Magazine artwork can be photocop- Class-A Headphone Amplifier Wanted Having built the SC480 amplifier with great results, along with several of your smaller projects, I have one suggestion and one question. Suggestion: how about a Class-A headphone amplifier design of high quality? I am sure that the recent class-B design is very good, with almost unmeasurable distortion but class-A seems ideally suited to a situation where not much power is needed and has an allure for audio­philes, similar to tube power! Question: would it be possible to use the 15W class-A design from 1998 (available from Altronics) as a headphone amplifier and if so, what resistor configuration would 98  Silicon Chip be needed? Alternatively, would it be possible to reduce the power of this amplifier so it is more suited to drive headphones; eg, in the 50 to 100-ohm region? (R. R., Auckland, NZ). • Your questions pose an interesting paradox. In fact, if all you want to do is to drive headphones (via say 100W resistors) then the SC480 would probably be equally as good as the 15W class-A amp. The reason for this is that most well-designed class-B amplifiers have very low distortion when they are lightly loaded. This is partly because the amplifiers are actually running in class-A at low power (ie, at the fixed quiescent current) and partly because output stage non-linearity is far less significant under light loading. While we have not performed specific tests under these conditions, we would expect the SC480 to perform virtually the same as the class-A 15W amplifier, provided you build Version 1, with TO-218 transistors So the quick answer is, if you want a high-quality headphone amplifier, just build the SC480. Furthermore, since it is not going to deliver much power, you will not need a big heatsink for the output transistors. siliconchip.com.au Malignant Moggie Mutilates Motor Vehicle I have a question for you regarding cats and cars. Recently, we replaced our 16-year-old car with a new one. This has created a serious problem with the family cat, as he has taken a liking to it. He sleeps on the new car and spends a great deal of time on it. He jumps on the car and because it is new and shiny, he uses his claws for traction and has left scratches on it. Has SILICON CHIP ever done an article or project on a cat repeller? I have used the Woofer Stoppers but they don’t work with cats. Have you any suggestions on how to keep the damn cat off our new car? (C. L., via email). • Putting the car in a garage or under a car cover may be the only practical answers. Woofer stoppers do work with some cats but your cat may be old and deaf. There is no simple electronic answer that we know of. Perhaps a PIR sensor could be set up to detect when the cat climbs on the bonnet and then an alarm could be triggered. However, that may not solve the problem of scratches on the car’s paint. Our readers could probably suggest any number of more permanent and drastic solutions not involving electronics but the editorial team at SILICON CHIP is sensitive, humane and caring. Serial-to-TCP/IP Converters from TRUSYS Trusys BF-430 & BF-450 universal serial device servers allow your industrial serial devices – such as PLCs, flow meters, gas meters, CNC machines and biometric identification card readers – to be monitored from your network. They support web management & firmware upgrade, while PPPoE & DDNS protocol allows Internet connection without static IP. Event alarm trigger is supported using e-mail & SMS (Short Message Service) to do real-time management for your system. Applications: ] Factory automation ] Hospital automation ] PLC instrument control ] Access control and security ] Time recording system For more information, call, fax, email or visit our website! ied onto high quality stock and then laminated. For even better results, try printing the EPS version from our website onto photographic quality inkjet paper. Again, lamination can be used for lasting protection. Good results can also be obtained with the “Scotchmark” laser labelling system. Silver and white polyester sheets are available from Wiltronics at http://www.wiltronics.com.au/ catalogue/shop.php?cid=262 They also have laminates that don’t require a special applicator. Yet another method was described in the April 2002 edition of SILICON CHIP, where we showed how to use the three-part “Quick-Mark” system from Computronics (see http://www. computronics.com.au/quickmark). If you want to design your own labels, then any graphics package that allows you to work in physical dimensions (eg, mm) would be suitable. We use CorelDraw (you don’t need the latest version for panel artwork). Coolmaster temperature controller for incubator I have ordered a Coolmaster Fridge/ Freezer Temperature Controller (SIL­ ICON CHIP, June 2005) to use as a controller for an incubator. Can you confirm that I only need to reverse the inputs to pins 2 & 3 on the LM311 comparator and adjust the values of the 3kW and 6.8kW resistors for the range siliconchip.com.au I require to make this work? I believe the positive feedback should still work correctly. (S. B., via email). • The answer is yes. Reviving an old Geiger counter A friend has asked if I could renovate an old Geiger counter for him. It uses a number of now unobtainable batteries in series but with those missing, it is hard to ascertain what they could be. Obviously, if the supply voltage could be emulated to see if it is easily fixable/operational, it’s worth doing. I would appreciate if any readers could shed any light on it. It is branded Ratec, model 115F. (B. B., via email). Nulling the Galactic Voice I purchased a Galactic Voice kit (SILICON CHIP, September 2006) as a present for my son. I had a pleasant afternoon assembling it and I found your instructions easy to follow and the detailed content very good. When I switched it on it appeared to be working. I had feedback coming out of the speaker which I could control and I could hear myself quite easily when I spoke into it. But I don’t think I am getting the full range of sound out of it. I followed your set-up instructions concerning VR1 & TRUSYS 95 McCanns Rd Mt Duneed Vic 3216 Tel: 0428 282 222 Fax: 03 5264 1275 Email: sales<at>trusys.com.au www.trusys.com.au Silicon Chip Binders REAL VALUE AT $13.95 PLUS P & P These vinyl binders will protect your copies of SILICON CHIP. They hold 12 issues & will look great on your bookshelf. Price: $A13.95 plus $A7 p&p per order. Available only in Aust. Buy five & get them postage free. Silicon Chip Publications PO Box 139 Collaroy Beach 2097 Or call (02) 9939 3295; or fax (02) 9939 2648 & quote your credit card number. February 2007  99 SC480 Amplifier Housing & Power Requirements I am looking at mounting four SC480 Version 1 amplifier modules into a 2U rack-mounting enclosure to make a 4-channel amplifier. I have several questions regarding the power, fuses, ergonomics and heat issues. (1) Seeing as the transformers used are of the laminated type and not toroidal, will there be any effect if four are placed within close proximity of each other (ie, 10mm separation)? I have heard that lam­ inated transformers generate a magnetic field eight times stronger than their toroidal counterparts. (2) If four of the SC480 amplifiers and their respective power modules are mounted in a metal chassis (Jaycar 2U Pro grade Rackmount Enclosure), will there be any thermal issues? Would installing an exhaust/blower fan help? (3) When earthing the chassis using spade lugs, is it necessary to mount a spade on every panel or is the conduction through the screws VR4 and checked the power supply to IC1, IC2 & IC4. You say to adjust VR4 so that the tone heard when there is no noise present at the microphone is at minimum. What tone? Am I expecting too much from the kit or do I have a possible problem? (G. B., via email). • The tone is the frequency emanating from IC2 that is not fully nulled in IC3. VR4 is adjusted to minimise this. Set the depth (VR1) fully clockwise and VR3 about half way. Then you may need to rotate the effect (VR2) one way or the other to hear any tone. If the Galactic Voice appears to work and you can get the modulated voice effect with the depth control set clockwise, rather than a clear voice sound, then the unit is probably working correctly. PC IR remote control under Linux I bought the PC IR Remote Control kit from Jaycar a year or so ago and it works great in Windows. However, I am trying to migrate to a Linux system at the moment and the only thing I 100  Silicon Chip sufficient? Also, is an automotive type crimper suitable for these earth connections or is a ratchet crimper required? (4) The chassis IEC power connector has a built-in fuse. Should I use this as a “master” fuse instead of four separate 3A fuses? If so, what value should be used? Or do the four fuses need to be installed as well? Alternatively, can you forgo the four internal fuses and use the “master” fuse only? (N. K., via email). • It would be best to power all amplifiers from a common power supply. This could be constructed from a 300VA toroidal transformer with dual 25V secondaries, two 10,000mF 50V capacitors and a 35A metal bridge rectifier. Using separate power transformers, rectifiers and filter capacitors is a recipe for hum and circulating earth current problems. We strongly recommend against that approach. Mount the bridge rectifier on a metal plate (eg, the chassis) for cool- haven’t been able to get going so far is the remote control kit. I have looked on the site and on the net in general for any information that may assist me on getting this device to work in Linux but to no avail. I am trying to set up the unit to work with lirc (http://www.lirc.org) and even though I have followed the installation instructions as precisely as I can, there is no output at all when I “cat /dev/lirc/0” or “cat /dev/ttyS0” (after re-enabling kernel support for the port). I also tried “cat /dev/ttyS0 | od -t x2” to convert it to hex but seeing as it’s not getting anything from the device, it shows up blank too. In girder I have the device set as follows: Baud Rate: 9600 Parity: None Word Size: 8 Stop bits: 1 Handshaking: None Character Events: Enabled, Fixed Length <at> 4 characters, Translate bin->hex enabled I was wondering if you could supply any information that would assist me ing and keep the leads between it and the transformer as short as possible. Altronics offer a convenient mounting board for snap-in capacitors (Cat K-3010). Note that the slight reduction in supply voltage (35V versus 40V) will reduce the maximum RMS output power by up to about 10-12W, which would hardly be noticeable. If you mounted each amplifier on its own heatsink inside the case, then some sort of ducted cooling would certainly be required. The earth wiring must be crimped with a ratchet crimper. If you can’t afford one of these, then use solderable spade lugs such as the DSE H-5012 and matching plastic cover H-5022. Mount the main earth point on the base of the chassis. The other panels may have to be individually wired back to this point if they do not make reliable contact through their mounting points. in getting lirc up and running with this device, as I cannot find anything that would let me set these settings. In Windows, I found that setting the baud rate to anything other than 9600 tends to either get nothing from the device or a constantly changing value. I believe this is my problem in lirc (I think lirc tries talking to the device at the highest speed the port is able to go). Thanks in advance. (A. T., via email). • We have no expertise with Linux serial ports. However, it appears that the PC Infrared Remote Receiver should work with recent releases of lirc, given the appropriate configuration. Your serial port must be configured for a speed of 9600 baud with 8 data bits, no parity and 1 stop bit (8N1). When used with an RC5-compatible remote, the receiver generates a string of four bytes for each key press, composed as follows: byte 1 – start record (always $FE) byte 2 – equipment address byte 3 – key code byte 4 – checksum (two’s complement) of bytes 2 & 3 For a Sony Playstation remote, the siliconchip.com.au Headphone Amplifier For Serious Hearing Loss In common with many others of advanced years I find that my hearing has deteriorated considerably. Response seems to be about -40dB at 10kHz and I don’t like to think what it might be at 15kHz. I have tried hearing aids with somewhat disappointing results. Since my main concern is listening to TV audio, I find that using headphones improves comprehension as much as the hearing aids. Is there a headphone amplifier capable of treble boost to compensate for the hearing loss? Ideally, it would have selective boost at (say) 2kHz, 5kHz & 10kHz of +40dB. (W. B., via email). • We don’t have good news. If your response is -40dB at 10kHz, there will be no response at all at 15kHz key code is two bytes long, for a total of five bytes per key press. You can see this for yourself by using a serial terminal such as RealTerm (for Windows), available from http:// realterm.sourceforge.net Set your terminal program to convert the incoming hexadecimal codes to ASCII. In RealTerm, you’d do this by setting “Display As” to “Hex[space]”. Modifying the V8 doorbell Some months ago, I built the V8 doorbell kit (SILICON CHIP, January 2005) and it sounds great. Now I want and no amount of treble boost will make it audible. This is a classic “brick wall” response. Nor is boosting the response by +40dB at 10kHz a practical proposition since it means that the power delivered at 10kHz needs to be 100 times more than at 1kHz. In practice also, applying a lot of boost at frequencies much above 5kHz or 6kHz does not really improve intelligibility by very much. Applying large amounts of tone boost also can lead to amplifier instability and possibly damage to the headphone drivers. In short, the news is not good. You have already discovered the most effective approach – use a good pair of headphones. We regret we cannot offer a more constructive answer. to be able to control the effective engine speed by an external voltage or TTL pulse input. I have had a look at the PIC controller code but don’t understand what I need to do yet. Any pointers in the right direction would be appreciated. I’d like to hear how it sounds when the acceleration rate is slowed down and controlled by external means (a potentiometer?). (C. C., via email). • The rate can be adjusted to some extent with IC4. You can also experiment with changing the 33kW resistor at pin 3 of IC4. A 100kW trimpot can be used to alter the frequency. You can also slow the acceleration rate a little by changing the 10mF ca- Notes & Errata Power Tool Charging Controller, December 2006: the paragraph on page 37 under “Adjustments” should say: “Trimpot VR4 is adjusted so that the voltage between TP4 and TP GND is 2.5V when the thermistor is at 25°C. Alternatively set the trimpot for 2.2V at 30°C or 2.8V at 20°C”. Note also that this controller cannot be used to control the 240VAC mains input to any drill charger. As clearly indicated in the article, it must only be used to control low-voltage circuits. Mains Frequency Monitor, Circuit Notebook, July 2006: pins 5 & 6 of the LM311 voltage comparator (IC6) should be connected together to prevent spurious noise pick-up. 3-digit LED Stopwatch (Circuit Notebook, January 2007): the PICAXE program has been updated to eliminate a bug that occurs at each minute interval. The update (version 1.1) can be downloaded from our website in the file “Stopwatch.bas”. pacitor following the 1kW resistor at pin 9 of IC1. A much larger value will reduce the acceleration effect. The software code is commented, particularly at the points where you can make changes. You would need to read the comments to find out where SC the changes can be made. 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 February 2007  101 MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. CLASSIFIED ADVERTISING RATES Advertising rates for these pages: Classified ads: $27.00 (incl. GST) for up to 20 words plus 80 cents for each additional word. Display ads: $49.50 (incl. GST) per column centimetre (max. 10cm). Closing date: 5 weeks prior to month of sale. To book your classified ad, email the text to silicon<at>siliconchip.com.au and include your credit card details, or fax (02) 9939 2648, or post to Silicon Chip Classifieds, PO Box 139, Collaroy, NSW, Australia 2097. _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Enclosed is my cheque/money order for $­__________ or please debit my o Bankcard   o Visa Card   o Master Card Card No. Signature­­­­___­­­­­­­­__________________________ Card expiry date______/______ Name _________________________________________________________ Street _________________________________________________________ Suburb/town ______________________________ Postcode______________ Phone:______________ Fax:______________ Email:___________________ 102  Silicon Chip FOR SALE More control solutions for you! NEW Netiom UDP: a budget priced Ethernet card ($225) which you can use for control and monitoring. NEW Protocol Gateways: Lonworks to Modbus, Profibus to Modbus, Can(J1939) to Modbus, AB-DF1 to Modbus and more NEW Range of serial LCD displays and touch screens. Easily connected to a range of PLCs. NEW Low Cost Dual DC Amplifier Kit: perfect for Data Acquisition. Amplify signals from 1.5 to 10 or reduce signals by a factor of 0.7 to 0.1 Serial Stepper Motor Controller card will now control motors up to 7500pps Motor Controllers from Pololu: we have a range of DC motor and servo motors.These motor controllers have been designed for robotic applications. Electronic Thermostats with digital temperature display; 2 control relays can be used in heating and cooling. NTC thermistor or J T/C or Pt100 sensors. Isolated and Non Isolated RS232 to RS485 converters. USB to RS422/RS485 converter with 1500V Isolation, RTS or Auto Data Flow control. Signal Conditioners non-isolated and isolated: convert thermocouples, RTDs to 4-20mA or 0-10V. Fully programmable. Stepper Motors: we have a selection of stepper motors for hobby and high torque CNC applications. DC Motors for both hobby and high torque applications. DC, Stepper & Servo Motor controller kits. Serial and Parallel Port relay controller cards. PIC MicroProgrammers: serial and USB port operated. Switch Mode, Battery Chargers and DC-DC converters. Full details and credit card ordering available at www.oceancontrols.com.au Helping to put you in control. CENTRAL COAST FIELD DAY, Sunday 18th Feb. Don’t miss Australia’s biggest siliconchip.com.au ELNEC IC PROGRAMMERS High quality Realistic prices Free software updates Large range of adaptors Windows 95/98/Me/NT/2k/XP VIDEO - AUDIO - PC distribution amps - splitters digital standards converters - tbc's switchers - cables - adaptors genlockers - scan converters bulk vga cable - wallplates CLEVERSCOPE USB OSCILLOSCOPES 2 x 100MSa/s 10bit inputs + trigger 100MHz bandwidth 8 x digital inputs 4M samples/input Sig-gen + spectrum analyser Windows 98/Me/NT/2k/XP IMAGECRAFT C COMPILERS ANSI C compilers, Windows IDE AVR, TMS430, ARM7/ARM9 68HC08, 68HC11, 68HC12 DVS5c & DVS5s High Performance Video / S-Video and Audio Splitters MD12 Media Distribution Amplifier QUEST ® Quest AV® HQ VGA Cables GRANTRONICS PTY LTD www.grantronics.com.au Satellite TV Reception SPK360 3/5/06 1:10 PM Page 1 20 years experience! 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 HI-FISPEAKER REPAIRS SPK360 YOUR EXPERT SPEAKER REPAIR SPECIALISTS Specialising in UK, US and Danish brands. Speakerbits are your vintage, rare and collectable speaker repair experts. Foam surrounds, voice coils, complete recone kits and more. Original OEM parts for Scan-Speak, Dynaudio, Tannoy, JBL, ElectroVoice and others! 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°. tel: 03 9647 7000 www.speakerbits.com Amateur Radio exhibition and sale of new and used radio and communication equipment at Wyong Race course, just 1 hour north from Sydney. Gates open 8.30am. Special Field Day bargains from traders and tons of disposals gear in the flea market. Exhibits by clubs and groups with interests ranging from vintage radio, packet radio, scanning, amateur TV and satellite. www.ccarc. org.au. Ph (02) 4340 2500. AMPLIFIER BUILDERS; ezChassis® pre-punched cabinets make all your DIY amplifier projects easier and professional looking. Matching heatsinks, handles and sockets. www.designbuildlisten.com siliconchip.com.au DOWNLOAD OUR CATALOG at www.iinet.net.au/~worcom WORLDWIDE ELECTRONIC COMPONENTS PO Box 631, Hillarys, WA 6923 Ph: (08) 9307 7305 Fax: (08) 9307 7309 Email: worcom<at>iinet.net.au CLEARING ALL STOCKS of throughhole ICs for free. You pay $2.00 for post & pack. Limit 10 per customer. Go to www.lazar.com.au INSTRUMENTS: precision multimeter & manuals HP3458A $2,500, 1 Meg GW audio oscillator $75, frequency counter HP5135 $275, Tektronix 224 oscilloscope $650. Allan 0408 622 371 VGA Splitter VGS2 AWP1 A-V Wallplate Come to the specialists... ® Quest Electronics® Pty Limited abn 83 003 501 282 t/a Questronix Products, Specials & Pricelist at www.questronix.com.au fax (02) 4341 2795 phone (02) 4343 1970 email: questav<at>questronix.com.au www.dontronics.com has 300 selected hardware and software products available from over 40 world wide manufacturers, and authors. Olimex Development Boards & Tools: ARM, AVR, MAXQ, MSP430 and PIC. Atmel Programmers And Compilers: STK500, Codevision C, Bascom AVR, FED AVIDICY Pro, MikroElektronika Basic and Pascal, Flash File support, and boot loaders. PICmicro Programmers And Compilers: microEngineering Labs USB programmers, adapters, and Basic Compilers, DIY (Kitsrus) USB programmers, MikroElektronika Basic, Pascal, DSpic Pascal Compilers, CCS C, FED C, Hi-Tech C, MikroElektronika C, disassembler and hex tools. CAN: Lawicell CANUSB, CAN232 FTDI: USB Family of IC ‘s. FT232RL, FT2452RL, also BL and others. 4DSystems LCD/Graphics: Add VGA monitor, or OLED LCD to your micro. Simple Serial I/F. Heaps And Heaps Of USB Products: TTL, RS-232, RS-485, modules, cables, analyzers, CRO’s. Popular Easysync USB To RS-232 Cable: Works when the others fail. Only one recommended by CBUS. Money back guarantee. www.dontronics-shop.com February 2007  103 Do You Eat, Breathe and Sleep TECHNOLOGY? Opportunities for full-time and part-time positions all over Australia & New Zealand Jaycar Electronics is a rapidly growing, Australian owned, international retailer with more than 39 stores in Australia and New Zealand. Our aggressive expansion programme has resulted in the need for dedicated individuals to join our team to assist us in achieving our goals. We pride ourselves on the technical knowledge of our staff. Do you think that the following statements describe you? Please put a tick in the boxes that do: Knowledge of electronics, particularly at component level. Assemble projects or kits yourself for car, computer, audio, etc. Have empathy with others who have the same interest as you. May have worked in some retail already (not obligatory). Have energy, enthusiasm and a personality that enjoys helping people. Appreciates an opportunity for future advancement. Have an eye for detail. RFMA Why not do something you love and get paid for it? Please write or email us with your details, along with your C.V. and any qualifications you may have. We pay a competitive salary, sales commissions and have great benefits like a liberal staff purchase policy. Send to: Retail Operations Manager - Jaycar Electronics Pty Ltd P.O. Box 6424 Silverwater NSW 1811 Email: jobs<at>jaycar.com.au Jaycar Electronics is an equal opportunity employer and actively promotes staff from within the organisation. Advertising Index 555 Electronics............................. 47 Agilent Technologies...................... 3 Altronics.................................. 84-87 Amateur Scientist CDs............... IBC Av-Comm................................... 103 Dick Smith Electronics............ 18-23 Dontronics.................................. 103 Ecowatch.................................... 103 RF Modules Australia Low Power Wireless Connectivity Specialists Applications: BIM1-151.300-10 Rural VHF FM Transceiver UHF FM Transceiver Utilities In Stock NOW! In Stock NOW! Industrial Range: 5km+ Range: 250m Commercial Power: 100mW Power: 10mW Data rate 10kbps Government Data rate: 64kbps Also: 151.275 & 151.6MHz BiM2T & BiM2R coming Meter Reading RADIOMETRIX: Low Power, Licence Exempt Radio Modules BIM2-433-64-5V RF Modules Australia. P.O. Box 1957 Launceston, TAS., 7250. Ph: 03-6331-6789. Email: sales<at>rfmodules.com.au. Web: rfmodules.com.au Elan Audio...................................... 9 Futurlec.......................................... 9 Grantronics................................. 103 Harbuch Electronics..................... 77 Instant PCBs.............................. 103 Jaycar ....................... IFC,49-56,104 JED Microprocessors..................... 5 LN Marketing................................ 93 MicroZed Computers.................... 73 Ocean Controls.......................... 102 Quest Electronics....................... 103 RCS Radio................................. 104 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. RCS RADIO/DESIGN is at 41 Arlewis St, Chester Hill 2162, NSW Australia and has all the published PC boards from SC, EA, ETI, HE, AEM & others. Ph (02) 9738 0330. sales<at>rcsradio. com.au, www.rcsradio.com.au PCBs MADE, ONE OR MANY. Any format, hobbyists welcome. Sesame Electronics Phone (02) 9593 1025. sesame<at>sesame.com.au www.sesame.com.au SWITCHMODE 5V reg. module kit just $6, or $7 built. 10.5 inch 7-segment dis104  Silicon Chip Parallax Basic Stamps The awesome simultasking 8-core Propeller Chip. Lots of sensors and Development kits + Robots. Ultrasonics, PIR accelerometer. Serial LCD display, serial keypads. Stepper Motor Controllers & Motors Micro stepping up to 25,600 fully protected industrial grade controllers at incredible prices. PCB mount units with full 32 bit indexer capability. DIN rail mount controller for factory applications. See our website for details and PDF file. Call or email us for application assistance. ron<at>nollet.com.au R T Nollet: Ph (03) 9338 3306; fax (03) 9338 4596; mobile 0407 804 712. www.nollet.com.au play kit from $30. LEDs, nixies, kits, lots of other stuff. www.ledsales.com.au KIT ASSEMBLY NEVILLE WALKER KIT ASSEMBLY & REPAIR: • Australia wide service • Small production runs • Specialist “one-off” applications Phone Neville Walker (07) 3857 2752 Email: flashdog<at>optusnet.com.au RF Modules................................ 104 Rockby Electronics......................... 7 RS Components............................. 6 RTN............................................ 104 Sesame Electronics.................. 104 Silicon Chip Back Issues......... 94,95 Silicon Chip Binders..................... 99 Silicon Chip Bookshop............ 96-97 Silicon Chip Subscriptions........... 83 SC Perf. Elect. For Cars.......... 48,92 Speakerbits................................ 103 Telelink......................................... 73 Trio Smartcal....................... 13,OBC Trusys........................................... 99 WES Components........................ 45 Worldwide Elect. Components... 103 PC Boards Printed circuit boards for SILICON CHIP designs can be obtained from RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. siliconchip.com.au