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Australia’s Electronics Magazine SILICON SILICON CHIP CHIP SEPTEMBER 2001 ISSN 1030-2662 6 $ 60* INC GST 09 NZ $ 7 50 INC GST PRINT POST APPROVED - PP255003/01272 9 771030 266001 siliconchip.com.au 21 PAGES OF MP3: What’s W hat’s in in MP3 MP3 for for you? you? Rippers Rippers and and Encoders Encoders MP3 MP3 I-R I-R Jukebox Jukebox To To Build Build PLUS: Noise N oise M Masking asking Aid Aid for for Tinnitus Tinnitus SSnooper nooper LLong ong RRange ange Mic Mic PPC-Controlled C-Controlled PPower ower SSwitch witch Notebooks SSony’s ony’s VVAIO AIO N otebooks IImproving mproving ’’Net Net SSecurity ecurity Newsgroup Codes EEmail mail & N ewsgroup C odes SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings.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.dominion.net.au Contents Vol.14, No.8; September 2001 www.siliconchip.com.au FEATURES 6 MP3: Changing The Way You Listen To Music MP3 is the new music buzzword. Find out how it works and what’s in it for you – by Jim Rowe 12 Making MP3s: Rippers & Encoders Want to make your own MP3s? We show you how with this comprehensive guide – by Greg Swain 16 Sony’s VAIO Notebook Computer We wanted to keep it but Sony asked for it back – by Ross Tester 88 Writing Articles For Silicon Chip Do we accept contributed articles? Yes, we do. Here are some general guidelines to increase your chances of success – by Leo Simpson 92 Newsgroups: Common Terms & Abbreviations Everything on newsgroups that you wanted to know but were afraid to ask. Our article lists the terms and the abbreviations. PROJECTS TO BUILD 24 Build Your Own MP3 Jukebox; Pt.1 Here’s a fantastic way to play your MP3s. It’s based on a PC and features infrared remote control and an LCD to display track titles – by Peter Smith Build Your Own MP3 Jukebox – Page 24. 36 PC-Controlled Mains Switch Build this project and team it with an old PC to control external devices. It works on anything from a 386 up! – by Trent Jackson & Ross Tester 62 Personal Noise Source For Tinnitus Sufferers Portable device generates soothing pink or white noise to mask out unwanted sounds – by John Clarke 70 The “Sooper Snooper” Listen in on conversations, bird calls, noisy engine bearings or even the sounds of termites munching into your home – by Ross Tester COMPUTERS PC-Controlled Mains Switch – Page 36. 12 Making MP3s: Rippers & Encoders Want to make your own MP3’s? We show you how with this comprehensive guide – by Greg Swain. 77 Using Linux To Share An Internet Connection, Pt.4 Final article shows how to improve security by shutting down unnecessary services – by Greg Swain SPECIAL COLUMNS 57 Serviceman’s Log From here, there & everywhere – by the TV Serviceman 84 Vintage Radio The Healing R401E/S401E mantel radio – by Rodney Champness DEPARTMENTS 2 Publisher’s Letter 4 Mailbag 46 Products Showcase www.siliconchip.com.au 68 Circuit Notebook 83 Subscriptions Form 98 Ask Silicon Chip The “Sooper Snooper – Page 70. 101 Notes & Errata 102 Market Centre 104 Advertising Index September 2001  1 PUBLISHER’S LETTER www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Peter Smith Ross Tester Rick Walters Reader Services Ann Jenkinson Advertising Enquiries David Polkinghorne Phone (02) 9979 5644 Fax (02) 9979 6503 Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Julian Edgar, Dip.T.(Sec.), B.Ed Jim Rowe, B.A., B.Sc, VK2ZLO Mike Sheriff, B.Sc, VK2YFK Philip Watson, MIREE, VK2ZPW Bob Young 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, Dubbo, NSW. Distribution: Network Distribution Company. Subscription rates: $69.50 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial & advertising offices: Unit 8, 101 Darley St, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9979 5644. Fax (02) 9979 6503. E-mail: silchip<at>siliconchip.com.au ISSN 1030-2662 MP3 format will change our music listening This month we have put a big effort into producing articles on MP3. The first is the general article on the MP3 format written by Jim Rowe and starting on page 6. The second, written by Greg Swain and starting on page 12, is more into the nitty-gritty of down-loading .WAV files and converting them into MP3 format. Finally, the third article by Peter Smith and starting on page 24, is the first of a series on building an MP3 player based on an old computer – not too old mind you, since it needs to be a 133MHz Pentium or better, with a big hard disk. In spite of the vast amount of work that we have put into the MP3 articles in this issue, I have mixed feelings about MP3. On the one hand it is growing enormously in popularity as people use it to download and copy all sorts of music in a format which is potentially high quality, very compact and easy to play, although currently available portable MP3 players are an expensive item. On the other hand, in the form that most people appear to use it, MP3 is the garbage music medium. In effect, it is the digital equivalent of the old tape cassette where ease of use won out over sound quality. In fact, most tape cassettes were recorded without the aid of Dolby noise reduction which was able to greatly improve the sound quality. And so it is today. MP3 is a potentially very good sound recording medium but is mostly used in the more mediocre modes where people get more recording time and less quality. Partly, people are forced into this situation by the limitations of the hard disk in their computer and the lack of speed of the internet. So while some people will accuse me of being elitist, I hate the idea of a recording medium being used at far less than its optimum. So in spite of there being rough equivalence between the better modes of MP3 and CDs, CDs ARE much better than the more compressed forms of MP3. We also have the interesting situation where audio manufacturers are pushing the CD medium to new highs with the development of SACD (Super Audio Compact Disc) and the DVD manufacturers are pushing the development of DVD Audio (ie, with six channels of digitally recorded audio). In the meantime, most of the population is supposedly quite happy to live with much more mediocre sound fare on MP3 and so on. I suppose there is a parallel here between high definition TV and the poor quality pictures that most of the population seem quite happy to watch. I hope that as time goes on, MP3 will continue to be developed and that people gradually raise their listening standards to the full potential of the medium. It can provide a great listening experience – why not use it to the fullest? Leo Simpson * Recommended and maximum price only. 2  Silicon Chip www.siliconchip.com.au .. AS AS In fact, SILICON CHIP is now the ONLY truly electronics-oriented magazine published in Australia. But if you want SILICON CHIP to continue to thrive; to continue as YOUR magazine, we need YOUR support. WE NEED YOU TO JOIN US – AS A SUBSCRIBER! You’ll not only save money, you’ll get your copy earlier than the newsstands, you’ll never miss an issue because it’s sold out . . . and if you’re in the electronics industry, it could be 100% tax deductible. CALL SILICON CHIP NOW ON (02) 9979 5644 OR TURN TO P83! September 2001  3 MAILBAG Practical electric vehicle wanted I wish to congratulate you all on a mighty fine magazine. I am wondering if you would ever consider designing a project for a practical electric vehicle, using an ordinary 3-phase AC induction motor and an inverter power supply, possibly with IGBTs and controlled by a PIC. AC induction motors have the advantage of having no brushes and are easily obtained. PICs have all the advantages that you already know about! Ian Horacek, Melbourne. Comment: we have often mulled over the idea of a designing an electric vehicle using, as you suggest, a 3-phase induction motor and a variable frequency/variable voltage supply, possibly running from a 240V battery bank (no inverter required and we’d use an American 220V 3-phase motor, rated at several horsepower). Even so, this would be a major engineering exercise, and more so if you wanted to incorporate dynamic braking and regener­ation. That’s why we have only thought about it, rather than actually doing anything. The approach used in golf buggies etc, using a DC motor, is much more practical. Widescreen on DVD, PAL vs NTSC and DVD Zoning As consumers, are we being conned with the hype of widescreen format, especially on DVD? Why I am asking this is because I was at a friend’s place a few weeks ago watching ‘What Women Want’ on video. It was in 4:3. A week later I hired it on DVD. I accepted the fact that this was presented in 16:9 wide-screen format but as the movie progressed I realised it wasn’t widescreen at all. It was just the 4:3 picture with black bars top and bottom. When I returned the DVD to the video store I had a few words to say to the staff, not at them, but about the indus­try. I then asked if I could get a comparison done in store and they saw what I saw. Out of curiosity, when Channel 7 screened Titanic recently, I did the 4  Silicon Chip same test as the DVD is in 2.35:1. Again the DVD had less picture top & bottom; ie, foreheads chopped off, etc. I thought widescreen was supposed to give more picture on the sides, not less picture top and bottom. On the point of 2.35:1, is there something special about 4:3 as 16:9 is [4:3]2 and 2.35:1 is very close to [4:3]3? Getting back to my gripe, as a result of this cropping we appear to be losing 25% of the DVD picture to black bars in 16:9 and 44% to 2.35:1, so am I correct in saying that when a 2.35 picture is enlarged to fit on a wide­ screen TV, the resolution would be 56% of the supposed 500 lines or about 281 lines? On another issue, in broadcasting, PAL is 625 lines while NTSC is 525 lines and claims are made of how superior the PAL picture is. When it comes to DVD or Standard VHS, how can the same claims be made. With DVD, 500 lines is 500 lines, be it PAL or NTSC, and 250 for VHS. Wouldn’t that give NTSC the edge, as it has 30 frames per second to PAL’s 25? Australia is a PAL country, though I am noticing more and more DVDs for sale in the NTSC format. Is this because Zone 4 includes Mexico, which uses NTSC, and we are receiving their overflow? Maybe I’m missing the point and require therapy, or am I right and brave enough to speak out? Simon Kareh, via email. BWD 820 oscilloscope schematic wanted My faithful BWD 820 oscilloscope which must be late 70s vintage refuses to sync to any source, even its own calibration square wave. On inspection, it is easy enough to identify the relevant section although a quick meter check of components reveals no culprit. Before I embark on the arduous task of tracing the circuit, I wonder if any SILICON CHIP reader has a schematic or know where I could get one? John Hansen, 12 Maskells Hill Rd, Selby Vic 3159. vcontrol<at>ozemail.com.au Unnecessary licensing is not the answer I have just read the discussion in your magazine for July on electric wiring and thought I would submit my view. If Austra­lia is ever to become the “Clever Country”, it must be through education of the population in the correct techniques and safety procedures in multi-discipline fields which include electrical wiring. In my opinion, unnecessary licensing is not the answer to accident prevention in the gamut of “Occupational Health and Safety”. We license those that drive motor vehicles, marine licensing and pilots to fly aircraft, etc and accidents still occur in abundance in all of these areas. It is in the education of the people in correct procedures as in New Zealand and other countries and not by restrictive licensing. If we continue down the let’s “license everything” path, Australia will not be known as the “Clever Country” but as the “cow’s tail” of the world – always behind. C. Bird, Anstead, Qld. Electrical regulations are highly discriminatory Let’s hope the campaign to change the electrical regulation works so that the discrimination ends! Personally, this is a very big threat, being qualified in electronics and having received extensive training locally and overseas to handle LV, MV and HV systems (from 6V to 32MeV) as part of the job when working on medical diagnostic imagining equipment. I have in my time worked on substations, computers, radio, rewound 6.6kV DC and AC motors used for railway locos www.siliconchip.com.au – the complete range of “volts” – and I am aware of the “bite” you can get. Yet I see it as discriminatory that I am effectively not allowed to do what I have been trained to do, because of some less than sensibly thought out legislation. This borders on the ridiculous, just the same as I faced trying to get an electrical licence. I asked the chief Electrical Inspectors office how I could get registered as an electrician and was sent packing, as I am too old to do an apprenticeship. Apparently this is the only way I can get a licence! How discriminatory, as I wanted to set up my own business and felt I would “do the right thing” and get licensed. No go. I can do the work but have to have a registered electrician come and check it over. Some of them have never seen the inside of 66kV substation let alone gone in and cleaned up the mess after one of the switch racks blew up! I hope your campaign bears fruit. T. Bradley, Ferntree Gully, Vic. People should not do their own wiring I have been reading your publication for 15 years. Nothing struck me as being quite so silly as the idea of people undertak­ing their own house wiring and repairing their own appliances. In the time I have been an electrician, I have witnessed some amaz­ingly dangerous handywork after someone has” had a go” at someth­ing and then brought it to me for correct repair. As for the service technicians, just because you work on TVs and videos does not mean you can work on consumer power safely. To become an electrician, as you know, takes four years of study and practice and I can assure you that there is much to learn. This is not withstanding industrial electrics, which is another world entirely. I feel a bent towards slander at some of the replies I have read toward electricians from your tech read­ers but I can assure you if you don’t know what you’re doing, as with anything, you can come unstuck badly. What I would also like information about is the insurance company’s point of view on an unqualified person doing the wiring. Will they cover you? I for one would not undertake any work on a premises that had been wired by an unlicensed person, insurance and personal safety being foremost to my mind. Just in closing, my personal favourite is the one where Joe Bloggs makes his own extension leads and gets the Active/Neutral around the wrong way. He claims it’s fine as the lead works anyway. If you want to work on certain things, at least get a restricted electrical licence for that purpose, so you are at least conversant with what you’re doing. Before you techs jump up and down, remember that dealing with 0.5A requires a different mindset than dealing with 50A. Bet you don’t print this. Peter Raffaelli, via email. Comment: 12 months ago, we would have mostly agreed with you but the fact that New Zealand, most of Europe and the US allow people to do their own wiring shoots your whole argument to pieces. Subscribe & Get this FREE!* *Australia only. Offer valid only while stocks last. THAT’S RIGHT – buy a 1- or 2-year subscription to SILICON CHIP magazine and we’ll mail you a free copy of “Computer Omnibus”. Includes articles on troubleshooting your PC, installing and setting up computer networks, hard disk drive upgrades, clean installing Windows 98, CPU upgrades, a basic introduction to Linux plus much more. Subscribe now by using the handy order form in this issue or call (02) 9979 5644, 8.30-5.30 Mon-Fri with your credit card details. MINI SUPER DRILL KIT IN HANDY CARRY CASE. SUPPLIED WITH DRILLBITS AND GRINDING ACCESSORIES $61.60 GST INC. www.siliconchip.com.au September 2001  5 MP3 Changing the way you listen to music MP3 is the new music buzzword. It “crunches” bloated audio tracks into compact files, for playback via your PC or a dedicated MP3 player. What’s in it for you? – read on and find out! By JIM ROWE D ESPITE THE JARGON, there’s nothing magical about MP3; it’s simply a technique for compressing digital audio, so that it needs less storage space and is faster to transmit from one place to another – via the Internet, for example. In many ways, MP3 is rather like the JPEG format that’s used to compress digital image files, so that more of them can be stored on your PC’s hard disc. In fact, the MP3 version of a piece of music can be 12-14 times smaller than 6  Silicon Chip the equivalent WAV file but still sound almost identical. You can get an even better appreciation of just how effec­tive MP3 is by looking at file sizes. Typically, a 4-minute CD-quality music track occupies about 45MB of disk space in WAV format but this shrinks to only about 4MB in MP3 format for near-CD sound quality. That’s a saving of about 40MB per track or 800MB for a 20-track CD! If necessary, even greater file compression ratios are achievable – it all depends on how much sound quality you’re willing to sacrifice. Is it legal? Being able to use a technique like MP3 to “shrink wrap” music into much smaller electronic packages has made it easier for people to swap music files over the Internet. It’s this aspect that the music industry doesn’t like, because the popular­ity of MP3 and other digital compression techniques has resulted in a dramatic increase in music “piracy”. However, just because people use MP3 to illegally obtain (or distribute) copyright music doesn’t mean there’s anything illegal about MP3 itself. MP3 is really nothing more than a file format and a lot of MP3s that are available via the Internet are quite legitimate. MP3s are often posted on the Internet by new bands as a means of self-promotion, for example. You can also make MP3s from your own audio CDs, LPs and tapes although, technically speaking, this can constitute a breach of copyright. However, many people take the view that it’s OK to copy provided they own the recordings and the MP3s are for personal use only. There are plenty of software tools available for “ripping” tracks off an audio CD and storing them on your hard disk in WAV format. After that the audio data has to be encoded in MP3 for­mat. Some programs only do ripping while others only do encoding but there are also plenty of combination ripper/encoders avail­able. www.siliconchip.com.au Microsoft’s “Windows Media Player 7” can play MP3s, conventional audio CDs and a host of other audio formats as well. It includes a playlist editor, supports extracting track titles from a CDDB and there are a number of interesting “visualisation” effects to choose from during playback. You can also customise the appearance of the player by applying different “skins”. Many of these software tools are available as freeware or shareware and can be readily downloaded from various sites on the Internet. You’ll also find MP3 rippers/encoders on computer magazine cover CDs. We’ll take a closer look at making your own MP3s later on. Why compress? As you’re probably aware, audio CDs and other digital media store music as a stream of binary numbers (ie, 1s and 0s). Each number specifies the amplitude of the original analog audio signal at a particular sampling instant. In the case of an audio CD, the sampling rate is 44.1kHz – ie, there are 44,100 samples every second – for each of the two stereo channels and each sample is stored as a 16-bit binary number. This means that for every second of a stereo recording, 88,200 of these 16-bit numbers must be stored on the CD. So when you’re playing the CD, the digital music “data” has to be read off the CD at the rate of 1,411,200 (16 x 88,200) bits per sec­ond, or about 1.33Mb/s (megabits per second). In practice, the total data rate when you’re playing a CD is actually about three times this, or about 4.3Mb/s, because additional “housekeeping” www.siliconchip.com.au data is needed for error correction, etc. After decoding and error correction, the 16 bits for each audio sample are fed through digital to analog converters (DACs), to deliver the two analog audio signals for a stereo amplifier. This type of digital recording is known as “linear pulse-code modula- The Creative Nomad IIc personal MP3 player connects to your PC’s USB port, comes with 32MB of RAM and costs $299 from Dick Smith Electron­ics. Also available from DSE is the deluxe Nomad II model for $398.00. tion” (or LPCM), because of the way it saves the sam­ples as “code” numbers whose binary value corresponds directly to the amplitude of the original audio at the sampling instant. LPCM certainly delivers excellent audio quality but this comes at a fairly heavy price in terms of data storage space and transmis­sion time. Even in its “raw” form as a WAV file on a computer hard disk, 16-bit/44.1kHz LPCM needs 1,411,200 bits or 176,400 bytes of storage space for every second of stereo audio. That’s just over 10MB (megabytes) per minute, which is why you need a big hard disk if you use your PC to make your own audio CDs. You can also see why LPCM isn’t really suitable for carry­ing the audio for digital TV or radio, or for sending music over the Internet. Even a 3-minute pop song would involve over 30MB of data, which would take about 93 minutes to download using your 56.6KB/s modem! Packing it in There are two different ways of compressing digital data. One method simply involves analysing the data for redundancy (ie, data repetition) and then encoding it more efficiently. In other words, it “packs” it more tightly and efficiently. At the other end, mirror-image decoding techniques are used to expand it again, restoring the original data exactly. This is known as “lossless” compression and it’s the kind of compression used for squeezing computer data into “zip” files. Lossless compression can achieve fairly large reduction factors with data that has a lot of redundancy, such as video (where one field image is often almost identical to the one before). But it’s not as effective with data that doesn’t have much redundancy, like music or speech. That brings us to so-called “lossy” digital compression. It is called “lossy” because it prevents the data from being re­stored exactly to what it was before – just “near enough” for practical purposes. These techniques are based on the idea of “perceptual coding”, which involves analysing the data on the basis of what we know about human perception (sight and hearing) and looking for content that either won’t be perceived or is unlikely continued on page 10 September 2001  7 Psychoacoustics: Fooling The Ear A Sound Pressure Level (dB rel. 0.2nBar <at> 1kHz) S YOU MAY already know, a typical normal ear’s frequency response varies considerably over the audio range and is also quite dependent on the volume of the sound. Our hearing is most sensitive at about 2-5kHz and least sensitive at frequencies below 100Hz. The response also varies a lot more at low volume levels than at high levels. In other words, our ears are quite non-linear and have a rather bumpy frequency response to boot. More recently, it’s also been discovered that because of the way our hearing receptor “hair cells” work inside the ear’s cochlea, the ear isn’t very good at hearing all of the components of a complex sound. In particular, a loud sound at one frequency tends to dominate our perception of all sounds in a band of frequencies, extending either side of the lound sound. This is called “masking” and is illustrated in Fig.1. What happens is that a relatively loud sound (signal A) “pulls up” the ear’s hearing threshold at frequencies on either side, so that if there are other sounds present in that frequency band at a lower level (like sound B), they simply won’t be heard. Essentially, the lower level sounds are “masked out”, because of the way our hearing receptors are desensitised at frequencies on either side of sound A. In practice, the width of this masking effect varies loga­rithmically with frequency. For example, a loud sound at 100Hz masks out other sounds from 50-150Hz, while another at 1000Hz masks out sounds from 5001500Hz and one at 10kHz masks frequen­ c ies from 5-15kHz. The higher the frequency, the wider the mask­ing curve in Hertz – see Fig.2. The width of these masking curves also varies with the volume. At low levels, only frequencies quite close to the main sound are masked but the masking widens as the sound level is increased – Fig.3. This means that the ear is best at distin­guishing adjacent sound frequencies at low volume levels. There’s another aspect of masking, too. As well as varying with frequency and volume, masking also varies with time. So when a fairly loud sound A starts at time T1 and ends at time T2, its masking effect doesn’t just last while it’s present but fades away relatively slowly after it ends (Fig.4). It can even start slightly before the loud sound is perceived – called “pre-mask­ing”. This “temporal masking” effect +120 +100 +80 Masking sound A +60 Masking threshold +40 Masked sound B +20 0 10Hz Normal hearing threshold in quiet 1kHz 100Hz 10kHz Frequency Fig.1: when you’re listening to a reasonably loud sound, you can’t really hear quieter sounds nearby — due to the masking effect. 8  Silicon Chip also varies with the dura­tion of the masking sound. The masking fades relatively quickly after brief loud sounds but takes longer to fade after long-duration loud sounds. So it’s been established that weak sounds at frequencies close to louder sounds simply can’t be heard. In addition, the masking effect varies with frequency, volume and time duration in a fairly predictable way. It’s this knowledge that is used to program the operation of perceptual encoders, like those used for MP3. Encoder operation Without going into things too deeply, the encoders operate in two main ways. First, they decide which audio components can safely be removed, because they’ll be masked and inaudible anyway – so they’re perceptually redundant. Second, they make decisions regarding how many (or how few) bits need to be used to encode the audio, on a dynamic “instant by instant” basis. To allow this to be done, the analog signal is not converted to digital samples as a single entity but is first filtered into a set of frequency sub-bands – typically 32 – with bandwidths of about 1/3 of an octave. The signal components in each sub-band are then sampled independently and the encoder then analyses each of their amplitudes. Then, by predicting the way the ear will handle each of these sub-band signals and the interaction between them, the encoder decides how many bits are needed to convey each one with sufficient accuracy and clarity. Louder sub-band components will be encoded with a larger number of bits and softer components with a smaller number of bits. Sub-bands where the signal level is below the threshold of hearing aren’t even encoded at all. This is called “adaptive sub-band coding”. What’s the point But what’s the point? Well, you’ll recall that LPCM uses a brute-force www.siliconchip.com.au Varying the bits On the other hand, by combining sub-band coding with a knowledge of the ear’s behaviour, it becomes possible to vary the number of bits used to encode each of the signal components, so that the quantising noise in each sub-band is still kept below the ear’s threshold of hearing (taking into account the effects of masking). This is done dynamically, so that the number of bits needed to convey the signal is not fixed but varies up and down, depending at any time on the signal itself. The net result is a dramatic reduction in the total number of data bits needed to store or transmit the audio, but with almost no “perceptible” difference in the sound of the signal decoded at the other end. Note that the decoded audio signal may well end up lacking many components or details that were in the original and may also have quite a bit of additional noise due to the cruder sampling of quieter signal components. But the crucial point is that these shortcomings are near enough to inaudible. If all this sub-band filtering, analysis and adaptive coding sounds pretty complicated, that’s because it is. In fact, this whole approach to signal compression only became feasible in the last 15 years or so, with the development of digital filter­ing and www.siliconchip.com.au Sound Pressure Level (dB rel. 0.2nBar <at> 1kHz) +120 +100 Masking thresholds +80 +60 +40 +20 0 10Hz Normal hearing threshold in quiet 1kHz 100Hz 10kHz Frequency Fig.2: the width of the masking threshold “skirts” varies logarithmi­cally with frequency. Sound Pressure Level (dB rel. 0.2nBar <at> 1kHz) approach, with fixed-length 16-bit numbers to repre­sent every sample of the signal regardless of its amplitude. This gives low “quantising noise” (theoretically -96dB below maximum level, for 16-bit sampling) and hence a large dynamic range. If we reduce the number of bits used to represent each sample, this lowers the amount of digital data being sent but the sampling would be cruder – ie, the quantising noise would increase. In fact the noise increases by 6dB each time we use one less bit, so if we drop to only 8-bit sampling we get a signal-to-noise ratio of only 48dB. So although 8-bit LPCM gives half the file size and trans­mission time of 16-bit LPCM, it also sounds pretty terrible. And 4-bit LPCM would be even worse. +120 +100 100dB +80 +60 80dB +40 60dB +20 0 40dB Normal hearing threshold in quiet 20dB 10Hz 1kHz 100Hz 10kHz Frequency Fig.3: the shape of the masking curve also varies with the volume of the masking sound, being much wider for loud sounds. Fig.4: masking also varies with time, taking quite a while to fade after a loud masking sound ends. signal processing techniques. It certainly wasn’t possible back in the old analog days but now it can all be done digitally by some dedicated LSI chips or software running on a PC. September 2001  9 MP3 Changing the way you listen to music – ctd from page 7 to be missed if it’s removed. The data that’s judged as “perceptually redundant” is then removed, allowing the remaining data to be compressed considerably. In other words, some of the audio information is “thrown away” on the basis that you won’t be able to hear the difference. By the way, lossy and lossless compression aren’t mutually exclusive – you can use them both together, for even more effi­cient data reduction. It’s this kind of “double shot” compression that’s used to squeeze up to two hours of digital video and 5.1-channel audio on a DVD and to pack up to 74 minutes of high quality stereo on a MiniDisc. It also happens to be the kind of compression used in MP3, to crunch down digital audio files by a factor of 10-14 times or more. But how does the perceptual encoding part of lossy compres­sion actually work? And how does the audio encoder decide which parts of the data can be safely chopped out, without being missed? Take a look at the accompanying panel on psychoacoustics to find out more on this subject. MPEG-1, Layer 3 Now we’ve looked at the broad principles on which digital audio compression are based, let’s turn our attention to MP3 itself. By the way its full official name is “MPEG-1 Layer 3”, which reveals that it’s one implementation of the group of digi­tal data compression technologies known as MPEG-1, developed and standardised by the Motion Picture Experts Group. MPEG-1 began as a technology to compress digital audio and video so they could be stored on CDs – ie, for video CDs. As such, MPEG-1 audio encoding was developed from two earlier tech­nologies called MUSICAM (Masking-pattern Universal Sub-band Integrated Coding And Multiplexing) and ASPEC (Adaptive Spectral Perceptual Entropy Coding). There are essentially three “layers” of MPEG-1 audio encod­ing, each involving a different level of processing complexity and offering a different degree of compression or “data reduc­ tion”. Layer 1 is the least complex in 10  Silicon Chip terms of processing and is designed for applications that don’t need a huge amount of data reduction. It reduces the audio data by about 4:1 and needs a data rate of about 384kb/s to give stereo reproduction of near-CD quality. Layer 2 involves more complex processing but reduces the audio data by between 6:1 and 8:1. It gives near-CD stereo repro­ duction at data rates of 192kb/s and above. Layer 2 is used for the audio on video CDs and for digital TV audio. Layer 3 (ie, MP3) involves the most complex processing, but also achieves the highest degree of data reduction – between 10:1 and 12:1. This allows it to provide near-CD stereo reproduction at data rates of 112kb/s or 128kb/s, or “FM stereo” quality at 64kb/s (21:1 reduction). Even a data rate of just 32kb/s can give respectable “AM mono” quality, with 15kHz sampling and a band­width of about 7.5kHz –see Table 1. Obviously, the big appeal of MP3 is this ability to give near-CD quality stereo with files only 1/12 the size of LPCM files, or FM stereo quality with files half that size again. That’s why it’s become so popular for down­loading music files over the Internet – because an MP3 file of a typical 3-minute song might take only seven or eight minutes to download, instead of 90 minutes or so for the equivalent WAV file. This also makes MP3 files very attractive for storing music on a PC Looking for MP3 music software? If so, www.mp3.com is the place to go. Iomega’s HipZip MP3 player uses 40MB PocketZip disks as the storage medium. hard disk or in the memory chips of a portable MP3 music player. As stated earlier, MP3 lets you cram a complete 4-minute track into just 4MB for nearCD quality but if you’re happy with lower quality, it can be even smaller. MP3 for all How can you take advantage of MP3 yourself? Well, there’s two fairly easy ways to get MP3 music files. One way of getting MP3s is to download them from the Internet, from the many web sites that specialise in making MP3 files available. Popular sites for this are www.mp3.com, www. scour.net and www.riffage.com but be warned – they’re often very busy and your browser may not be able to access them. One obvious drawback here is that the web sites may not have the particular pieces of music you want. They’re a bit of a lucky dip in this regard. The other main way to get MP3s is to make them yourself (see “Making MP3s”), by converting the tracks on existing audio CDs, LPs and tapes. This involves using a PC with a CDROM drive plus some readily available software. It’s a two-step process: you first turn the music into a WAV file (known as “ripping”), then encode it into an MP3 file (the “encoding” stage). To convert a track from an audio CD, for example, you first need to read the track and save it on your hard disk as a WAV file. This can be www.siliconchip.com.au done using either one of the common music editing programs (like Cool Edit, Sound Forge or CD Spin Doctor) or a ripper program. Many of these can be downloaded from the Internet, from sites like www.mp3.com Similarly, with a track from a tape or LP record, you again have to use one of the music editing programs to record it through your sound card. Once you have the music on your hard disk in WAV file form, you then use an MP3 encoding program to produce the MP3 equival­ent file. Again there are many MP3 encoding programs that you can download from the net. Alternatively, you can get a combined ripper/encoder that does everything in one seamless operation. Silicon Chip’s MP3 Jukebox Our MP3 Jukebox is basically a standard PC fitted with an infrared remote control receiver and an LCD screen to display the track titles. The universal remote control handpiece lets you select from up to 99 playlists, each containing up to 199 songs – just by pressing the buttons. Playing MP3s Once you have the music you want in MP3 form, there are various ways you can play it. One way is to play it on your PC via its sound card and amplifier/speakers, using an MP3-capable software program. If you’re running Windows 98/Me/NT, the latest Windows Media Player will play MP3 files directly (as well as conventional audio CDs). Alternatively, you can use a freeware MP3 player such as “Winamp”. As before, you can download these players from web sites like www.mp3.com or from a computer magazine CD-ROM. Another approach is to record the MP3 files on a CD-R disc, using your CD-writer drive and a program like “Easy CD Creator”. You can then play the files from the disc, either on your PC using Windows Media Player or Winamp, or on one of the latest DVD players that can play CD-R discs with MP3 files. MP3 on the move Yet another approach is to download the MP3 files from your computer into one of the shirt-pocket sized portable MP3 players, like the Diamond Rio 500 or 600, or the Creative Labs Nomad II. Many of these players have a USB port, so you can download the files into the player’s memory chips or card quite quickly. Most of the players can store up to an hour or so of high-quality 128kb/s stereo. In short, MP3 is quite a useful tool for making digi­tal audio widely available in surprisingly compact form. No wonder it’s become so popular! SC www.siliconchip.com.au H ERE’S A FANTASTIC WAY to play your MP3s. What we’ve done is design a remote control receiver and LCD display that plugs into the serial (RS232) port of your PC and is controlled by a universal remote control. An accompanying software program interfaces the unit with Winamp. With this setup, you can play your MP3s by remote control and all the track data is displayed on the LCD. The remote can select between 99 playlists, each listing up to 199 songs. You can either build the remote control receiver directly into your PC or mount it externally. In fact, it doesn’t even have to be in the same room as your PC. Instead, you could mount the remote control in your loungeroom and connect it via a serial (RS232) cable to a PC located in an adjacent room – eg, a bedroom or study. Of course, you would also have to run audio cables to con­nect the output from your PC’s soundcard back to your amplifier. You have to keep these cables short, though – any more than 4-5 metres and you could quickly run into hum and stability problems (not to mention high-frequency losses). One neat solution is to use a dedicated PC as an MP3 Juke­box. This could be sprayed charcoal gray and mounted next to your existing hifi gear. Once it’s working, you don’t really need a keyboard, mouse or monitor, since our remote control setup lets you power the unit down when not in use (provided you have an ATX motherboard, that is). In short, it’s up to you how you use the remote control unit. The first article on our MP3 Jukebox is on page 24 of this month’s issue. September 2001  11 Making MP3s: Rippers & Encoders By GREG SWAIN I N ORDER TO MAKE your own MP3s you’ll need ripping and encoding software. A combined ripper and encoder that can extract tracks from a CD and convert them into MP3 format in one seamless operation is usually the most convenient. However, there’s noth­ing to stop you from using one program to rip the tracks to WAV files and then using another program to convert them to MP3 format, if that’s what you prefer. You’ll also need a reasonably fast PC with a modern CD-R that’s capable of digital audio extraction (these CDRs are normally branded DA). If the CD-R doesn’t offer digital audio extraction, the sound must be sampled via the sound card and this gives somewhat lower quality (depending on the card itself). The main factor to consider when making MP3s is the bit rate. Higher bit rates produce better sound quality but they also create larger files. Table 1 on page 6 shows the bit rate options that are commonly available and the resulting sound quality. Generally, the settings to go for are: 128kb/s bit rate, 44.1kHz sampling and stereo – see Table 1. This will give good-quality sound but at the same time keep file sizes down, with a compression ratio of about 10.5:1. By contrast, a bit rate of 192kb/s gives a compression ratio of about 7:1, which means that the file sizes are about 50% bigger than at 128kb/s. That mightn’t sound like a lot but it can be important if you’re trying to squeeze the maximum number of tracks into the memory of a portable MP3 player. If file size isn’t critical, try increasing the sampling rate from 128kb/s to 160kb/s. This will give slightly better sound quality for only slightly larger file sizes. There can also be variations between different MP3 encoders, so you might like to experiment here. The Lame, Fraunhofer and Blade encoders are all reputed to produce good results. Most encoders set the sampling according to the bit rate selected. However, some of the fancier encoders give you a choice of sample rates – eg, 16kHz, 24kHz, 32kHz, 44.1kHz and 48kHz. Audio CDs have a sample rate of 44.1kHz, so there’s usually nothing to be gained by going higher than this. Lower sampling rates will reduce the file size but high-frequency losses quickly become noticeable. Some encoders also have a variable bit rate (VBR) option. When selected, this allows the program to automatically vary the bit rate according the frequencies present, so that the file size is kept to a minimum. Encoders with this feature also often let you set the minimum bit rates. Typical ripper/encoders Not looking to spend any money? Then take a look at CDex v1.40 (Beta6) – see Fig.1. This freeware MP3 ripper/ encoder offers all the functions you could want, including the ability to rip tracks off a CD and save them in WAV or Fig.1: CDex 1.4 (Beta 6) is a freeware ripper/encoder program that’s easy to drive and has lots of features. You can bring up the track titles by querying the CDDB over the Internet or by manually editing each track title in turn. 12  Silicon Chip www.siliconchip.com.au Fig.2: Audiograbber 1.8 is a comprehensive ripper/encoder but it will cost you $US25 for the non-crippled version. MP3 format in one operation. It can also convert existing WAV files on your hard disk to MP3s and even convert MP3s to WAV files, in case you want to record your MP3s in a format that can be read on a conventional audio CD player (eg, in your car). There’s also support for different bit rates (including VBR) and there’s a selection of inbuilt encoders (CODECs) to choose from. The default is the Lame MP3 encoder which gives excellent results. An interesting option is the inclusion of the Windows WMA encoder, which produces compressed files that can be played on the Windows Media Player. It’s easy to use. To rip files off an audio CD, you simply load the program and place the CD into the drive. This brings up a list of tracks as shown in Fig.1, after which you can select one of more tracks and convert them to WAV or MP3 format. The track titles in Fig.1 are shown as AudioTrack 01, AudioTrack 02 and so on but you can rename them before ripping by right-clicking each file in turn and typing in the correct track title. If that sounds like a lot of work (and it is), there’s an easy way out. In common with many other ripper/encoders, CDex supports a feature called “CDDB”, or CD Database. This is basi­cally an Internet database that identifies the CD and automati­cally supplies the track titles, the CD title and the name of the artist. In fact, there are two CD databases that you can use – cddb and freedb – and CDex uses the latter by default. Of course, you need an Internet connection in order to query a database. And that’s where there’s a trap – if you enable the “auto-connect” feature in CDex, the program will automatically dial out and connect as soon as the CD is loaded. Unless you have a perma­ nent connection, you’re much better off just clicking the “CDDB” button on the righthand edge of the window when you’re ready. An alternative is to use the CDDB that’s supplied with some CD-ROM burning software. In the case of Nero 5, for example, you just copy the cddb.zip file to your hard disk, unzip it (you’ll need about 130MB of free disk space) www.siliconchip.com.au Fig.3: Audiograbber’s “MP3 Settings” dialog lets you adjust the bit rate and choose the encoder to be used. If you want an internal encoder, just copy lame_enc.dll to the same folder as “audiograbber.exe”. Fig.4: this dialog appears during the MP3 conversion process in Audiograbber. and then enter the path to this file in the relevant setup window of your MP3 encoder. ID3 tagging Another feature offered by CDex is ID3 tagging. This allows you to enter in text information about each track – eg, the track title, artist, year and comments – which is then subsequently displayed by the MP3 player. The ID3 tags are written to the end of each MP3 file. Creating a playlist How do you get you MP3 player to automatically play a list of MP3s? Answer – you need to create a “playlist”. This is nothing more than a text file that contains a list of MP3s and you can add or delete tracks from the playlist simply by editing this file using a text editor such as Notepad. You can also rearrange the order in which the tracks are played and change the track title information that’s displayed by the MP3 player. You can also pull some rather neat tricks with the playl­ist. Want the MP3 player to repeat a particular track September 2001  13 several times? That’s easy – just add multiple entries of this track into the playlist. As with many other MP3 encoders, CDex can automatically generate a playlist for you at the end of the MP3 conversion process. This creates a file called “playlist. m3u” (all playlist files have a .m3u extension) that lists all the files that you’ve just converted. The playlist is automatically updated if addi­tional tracks are subsequently ripped and encoded as MP3s. You don’t have to use a text editor to edit the playlist, by the way. Some MP3 players, such as Winamp, include a playlist editor that makes the job easy. It’s also possible to edit the track titles before ripping using the MP3 encoder software, as pointed out previously. Audiograbber Another excellent MP3 encoder is Audiograbber v1.8 – see Fig.2. This offers all the features of CDex and a few more be­sides, although it doesn’t include an inbuilt MP3 encoder. That’s easily overcome by downloading and copying LAME’s freeware MP3 encoder DLL file (lame_enc. 14  Silicon Chip dll) to the same folder as “audiograbber.exe”. You will then have an internal MP3 encoder that goes all the way to 320kb/s. Lame_enc.dll is available from www.dkutsanov. chat.ru or you can simply download and unzip CDex.zip (see panel) to obtain a copy. Alternatively, you can use an external encoder such as BladeEnc. This is available as freeware from www.bladeenc.mp3.no – just point Audiograbber’s encoder settings to the folder that contains the BladeEnc.exe file. Unfortunately, the trial version of Audiograbber has been crippled so that you can rip only half the tracks on a CD in a single session. These tracks are randomly selected each time you insert the CD. It’ll cost you $US25 for the full working version. AudioCatalyst is essentially an updated version of Audio­grabber and includes its own MP3 encoder. Once again, the trial version is crippled but $US29 restores all the features. There are lots of other MP3 ripper/encoders available, in­cluding Earjam IMP, Easy MP3, Sonique, Easy CD-DA, www.siliconchip.com.au Fig.5: Winamp is a clever media player (MP3, CD audio, etc) that comes for free! Handy features include support for CDDB and a Playlist Editor (bottom). Fig.6: want to give Winamp a different appearance from the standard fare? Easy – just download and apply a new “skin”. This one is called “Spilt Milk”. Musicmatch Jukebox, Audio Converter and MP3 Creator, to name just a few. MP3 players You can use the Windows Media Player for playing back MP3s on your PC but our favourite is the freeware program Winamp (Fig.5). This versatile program boasts a Playlist Editor, an Equalizer, an inbuilt spectrum analyser and even a Minibrowser that lets you search web sites for MP3 files. Naturally, all the “normal” CD player controls are these, along with a volume control, a balance control and a shuffle control (oh yes, it also plays audio CDs). You can even change the look of the graphics by downloading and applying “skins” – see Fig.6. Using Winamp to replay MP3s is a “no-brainer” – just click the Play button and navigate to the folder where your MP3s are stored. Once there, you can either choose to play a single MP3 file or you can load a playlist (.m3u) file so that all the tracks in the playlist are played automatically. Alternatively, double-clicking on an MP3 file or on a playlist (.msu) file automatically starts the Play function. Clicking the little sinewave symbol at the top left of Winamp brings down a menu that also lets you Play files and launch the Playlist Editor, the Equaliser and the Minibrowser windows. These windows cleverly snap together and both the Playl­ist and Minibrowser windows can be resized by dragging. The Winamp and equalizer panels can be shown www.siliconchip.com.au Fig.7: there are lots of easy-to-follow options when it comes to configuring your copy of Winamp. double-size by choosing this option from the Options menu. The buttons along the bottom of the Playlist Editor let you edit the entries (add, remove, sort, edit track titles and ID3 tags, and save new playlists). You can also edit the track titles and ID3 tags by right-clicking the file in the playlist and choosing the appropriate option from the menu. Similarly, right-clicking on the Equaliser and on the Winamp player itself brings up other menu options. Really, it’s a lot more complicated in the telling than in the doing and 30 minutes is all it takes to come to grips with SC this intuitive and clever program. September 2001  15 Sony’s     Notebooks by Ross Tester Around the middle of last year, Sony introduced its new range of VAIO Notebooks. Now, twelve months later and with several new models on the market, we thought it about time to have a closer look at these intriguing machines. W hen Sony launched the VAIO computer range on the market, they described them as a “new concept” in personal computing. Was this just more marketing hype, or were they really something different? And that name, VAIO: what does it mean? To the uninitiated, it sounds like some sort of pathway. But to where? In fact VAIO is an acronym for Video Audio Integrated Operation. That in itself gives a pretty good clue as to this 16  Silicon Chip computer’s likely application: video and audio. In fact, that is precisely where I had my first introduction to the VAIO. During July and August last year, Sony VAIO computers were used extensively by NSW TAFE (Technical and Further Education) who were contracted by the Sydney Olympic Games Organising Committee to provide training to the 47,000 Olympics volunteers (and later the Paralympics Volunteers). As one of those trainees, I was impressed! The standard of audio/video presentation was outstanding – an excellent mix of video and Powerpoint-style “slideshows” which were shown to groups ranging in size from just a few up to many thousands via A/V projectors. I noticed at the time of training that name, VAIO, and wondered then what the significance of it was. It was only after the hectic period of the Games was over that I started to look a little deeper. And then in the July issue of SILICON CHIP Jim Rowe’s article on Digital www.siliconchip.com.au Audio Amplifiers jogged the memory “. . . have true digital audio amps, as does Sony’s new Playstation 2 and its VAIO handheld computers. . .” So we thought it might be opportune to have a closer look at one of these machines, particularly with regard to its graphics, video and sound handling capabilities. Sony were more than happy to lend us one of the models and so, before long, we were playing with a Sony VAIO FX770K. Now this is by no means Sony’s topof-the-line VAIO but it does come with some rather impressive specs. It wasn’t the graphics/video/sound oriented machine we had hoped to look at but is more a business-oriented product, albeit with pretty good performance in the graphics, video and sound areas. Hardware The microprocessor in this particular model is a 650MHz Mobile Intel Pentium III Processor featuring Intel SpeedStep Technology (more on this shortly), running with an Intel 815 EM chip set integrated graphics accelerator. The system bus is a standard 100MHz and it comes with 128MB of SDRAM and 32KB/256KB of cache memory (on chip). The hard drive is 20GB, divided into two 10GB logical drives and it sports an 8x DVD-ROM drive (which obviously also plays CDs – at up to 20x). ­There is a single type III PC card slot (or two type II) and it supports Cardbios. Other interfaces included are the standard 15-pin monitor, 25-pin parallel and 9-pin serial ports, plus two USB connectors, a 4-pin iLINK (IEEE 394) port and 3.5mm jacks for microphone in (mono) and headphone out (stereo). There is also an inbuilt 100 Base-T/10Base-TX Ethernet port built in. i.LINK, by the way, is a bi-directional digital interface for exchanging data, such as digital video clips and sound files, between devices that have i.LINK connectors, or for controlling other devices. An upgraded model, the PCGFX770TK, also has a built-in modem for accessing the Internet, point-topoint data communication, and so on. The floppy disk drive is removable (in fact, it is a normally supplied “option”. Removing the floppy drive (a two second operation) allows its port www.siliconchip.com.au From the left, the ports are USB, serial, parallel, external monitor and network (100 base-T or 10 base-T), with another USB port and DC power on the right. Here’s a close-up of the audio/video ports: the red socket is microphone, green is earphones or external (powered) speakers. Next is the i400 i-link port while the two buttons alongside release the PC-cards from their bays at right. to be used by other (optional!) devices. Software Reflecting the machine’s target business market, the operating system is Windows 2000 Professional, claimed to be the most stable Windows operating system yet. Some might argue that point! Other software included with the machine is DVgate 2.2, Movie-Shaker 2.0, Sony Notebook Setup, Picture-Gear 5.0, Smart Capture 4.1, OpenMG Jukebox 2.0, Smart Connect 3.0, Smart Connect Monitor 1.0, DVD Region Setting Utility, Adobe Acrobat Reader 4.0, Adobe Premiere 5.1LE, Quick-Time 4.1, Real Player 7 Basic, McAfee VirusScan and WinDVD 2000. LCD and keyboard On opening the VAIO and powering it up, arguably the most striking feature is the big, beautiful 14.1-inch (35.8cm) LCD colour TFT display capable of XGA (1024 x 768) resolution. Because it’s LCD, you tend to view this screen closer than you would a typical CRT monitor. It is very clear and crisp and even after extended use I didn’t find it at all tiring. Of course, you could plug in an external monitor and get up to 1400 x 1050 resolution. One of the common misconceptions about notebook computers is the size of their keyboards. Many people think that they are smaller than standard desktop keyboards but, with very few exceptions, they are the same size (they have to be, otherwise you’d make too many typing mistakes!). If you don’t believe us, measure, say, the numeral keys from 1 to 0 on your computer keyboard. From outside edge to outside edge, I’ll bet it’s around 185mm. On the Sony, as on most notebooks – 185mm! Of course, notebooks sacrifice the numeric keypad and function keys The other side of the case has the removable floppy disk drive (left) and the DVD player at right, shown here partially open. The touch-pad “mouse” can also be seen in this shot (middle left). The pad on the right is the touch-sensitive one while the two pads below it simulate left and right mouse buttons. September 2001  17 Some of the “help” files are, in my humble opinion, woefully inadequate. Here is the information you get on how to connect the computer to your network – basically, all it says is “plug it in”. For any more help you are supposed to contact the system manager of the network. What if you don’t have one? By the way, Sony are not alone here: help is becoming less and less helpful amongst most hardware and software! of desktop keyboards. For those who want a “numeric” keypad (eg, for fast data entry), the Sony places it on the M, JKL, UIO and 789 keys, activated by the “num lk” key. The various function keys are located on three sides of the alpha/numeric keys – it doesn’t take very long at all to get used to their locations. The normal mouse is replaced by a touch-sensitive pad. Draw your finger over the pad and the on-screen cursor follows the movement. Two large switch pads underneath the touch pad simulate the left and right mouse buttons. It takes a bit of getting used to when you’ve used a mouse for twenty years (especially on drop-down menus!!!) but in time, I believe it could be quite enjoyable. Sony is fairly noncommital about the type of graphics firmware – the spec simply says “hi-speed graphic accelerator”. It is based on Intel’s 815EM integrated chipset. In this particular VAIO there is no separate video memory – it shares up to 11MB with the main memory. The audio system is Windows Sound System compatible, AC97 compliant and features a software MIDI sound generator, 3D sound function and has the previously mentioned digital amplifier with a pair of inbuilt speakers. On this point, we have to be somewhat critical: we believe one of the main uses for a machine such as this is on-the-job presentations – say, for example, an advertising agency wanting to present a new campaign 18  Silicon Chip to a client. The audio simply isn’t loud enough! And even with ’phones plugged in, you could hardly describe it as mind-blowing. A pair of amplified speakers would solve the problem – but that’s something else to carry around. Incidentally, audio level, screen brightness and other functions are all controlled via the keyboard: audio, for example, is a “Fn” and F4 key combination, followed by right or left arrows to increase or decrease the volume (mimicked by an on-screen icon). Having the inbuilt network adaptor was a joy – I wanted to transfer some files from my office PC to the notebook and vice versa – it was simply a matter of plugging the Sony in, setting a few parameters and it talked to the network with no worries. I didn’t get a chance to fire up any USB devices, mainly because I didn’t have a suitable cable on hand. But with two USB ports included, the Sony VAIO would have no problems communicating with other USB devices. Dual speed One interesting feature of this particular notebook, which uses Intel’s “Speedstep” technology, is its automatic changeover to a lower-power mode on battery. With the AC adaptor plugged in, the machine operates at its maximum 650MHz. But if you unplug power, the screen automatically dims and the machine switches to “battery optimized performance”, dropping the CPU speed down to 500MHz. The battery is a 14.8V/1700mAh Li- ion type which can be swapped over. Incidentally, a fully-charged battery is rated to last 1.5 to 2.5 hours, depending on usage. The computer has an automatic “hibernate” mode when the battery is nearly exhausted, saving current work and settings to the hard disk drive before effectively turning itself off. From this point, nothing is lost when either the battery is recharged or the computer is run on AC. ­It also has a “standby” mode which shuts down most functions to save power (for example, if you are taking a break) but if the battery discharges completely in this mode, current work and settings would be lost. The AC adaptor is universal – 100 to 240V 50/60Hz so you can take it virtually anywhere in the world. Three so-called “power” keys above the keyboard allow instant (well, almost) connection to the Internet, to email (both assuming an external modem is connected) and also to go into standby mode, as mentioned above. Each of these keys is programmable to do other tasks if you wish. In use The VAIO PCG-FX770K is not the best performing machine in the range from a graphics and video handling point of view. It is obviously not intended to be – there are significantly more expensive VAIO models which are aimed squarely at that market. So we didn’t get the opportunity to run the VAIO through all the modes we would have liked. Instead, we used it in the mode intended – as a business computer with advanced video/audio capabilities. We’ve already criticised the audio level; no doubt, though, the vast majority of users would link this to an A/V projector so would not find that a problem. And as far as video goes, we’ve already commented on the beautifully clear, crisp screen. We ran the “Fantastia 2000” DVD as a test and the machine acquitted itself very well indeed – no dropouts, no freezes, no problems. The Sony is capable of playing DVDs from any region – up to a point. The DVD Region Setting Utility will allow you to change the region a few times – they don’t actually say how many – but once this limit is reached the machine is locked – permanently – on this region. Bad luck if you want to watch a Region 1 DVD and that’s your last www.siliconchip.com.au change – you’ll never be able to watch a region 4 (ie, Australian) DVD again. What’s the betting there will be a “crack” on the Internet soon for this little feature? We also loaded and ran a few applications which this type of machine would lend itself to. One program which very quickly sorts out the men from the boys, as far as operation goes, is Photoshop. While the screen re-writes weren’t as quick as we were used to with a comparable speed desktop computer, they were adequate – and the quality was excellent. In fact, I did some high-level photo manipulation using the VAIO then transferred the file to my desktop computer to compare results: there was nothing to pick between them. Colour accuracy was superb. As you might expect with 128MB of memory and a 20GB hard disk, there was precious little difference in “ordinary” applications such as Word or Pagemaker. But with the big advantage of go-anywhere performance, the VAIO has a definite edge. The “manual” A somewhat abridged operating www.siliconchip.com.au manual is supplied – basically, it’s just a getting started and trouble-shooting guide. The “real” manual is pre-loaded onto the computer’s hard disk. It’s a trend being followed by more and more manufacturers these days (printed manuals are expensive) but, speaking purely from a personal perspective, they are less satisfying than a “real” manual. It’s more of this push to make everything resemble web pages. Sure, you can almost instantly log on to the manual and look up what you want in the index. But I’d much rather have something I can read over and over in my hot little hand (OK, so I’m a slow learner). And the quality and quantity of the information leaves a little to be desired, too: for example, on the underside of the machine are at least three expansion sockets. Try as I might, I couldn’t find any reference to them or what they were for. Perhaps Sony intends them for factory options only. Well, they should say so – or at least explain what they are for. And another: there’s a section on connecting to a LAN via the Ethernet connector. I’ve reproduced the page to show the wealth (!) of information given. It’s typical – I would have expected much more.­ The verdict? At an rrp of $3799, the Sony VAIO PCG-FX770K does represent very good value for money, even with the limitations we’ve described. With 850MHz processor, 128MB of member and 20GB of hard disk drive to play with it’s going to handle most of the work you can throw at it and you won’t tire viewing that beautiful big LCD screen. The software supplied will more than get you started in audio and video. If you want more features, you’re going to have to spend more: the just-released FX-880K, for example, has a PIII 850MHz processor, a 15-inch TFT LCD screen, an inbuilt modem and all the bells and whistles of the FX770K – and costs $4699. Even more upmarket is the PCGR505 with a $5899 tag – but that includes a docking station. Anyway, that’s the Sony VAIO FX770K – in many ways exciting, in some ways disappointing. But overall the pluses far outweigh the minuses. The biggest minus of all: Sony have just called, asking for it back . . . SC spoilsports! September 2001  19 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.dse.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.dse.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.dse.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.dse.com.au MP3 Jukebox Build your own Want to impress your friends? Build this neat little project to control your PC’s MP3 player remotely! Alternatively, if you’re interested in adding remote control and/or LCD readout to an existing project, read on! Part 1: By PETER SMITH 24  Silicon Chip www.siliconchip.com.au O VER THE COMING months, we will describe how you can transform your PC into a veritable jukebox, able to play any of your favourite MP3s at the press of a button. And if you’re really serious about your MP3 music, you can even build a standalone PC-based player without a monitor or keyboard. We’ve received so many requests for MP3 projects that we just couldn’t ignore them. This project includes the most-requested features but omits some of the more radical – such as a Pentium III PC strapped in the car boot with a custom power supply, up-front console and remote control! What will the finished project do, exactly? Essentially, we’ve taken one of the most popular freeware music players on the Internet, Winamp, and added some software to allow it to be controlled remotely. IR Remote Receiver & Display Features • Works with most off-the-shelf • • • • • universal remote controls 16 character, 2-line LCD with backlighting Simple serial interface In-built mini-terminal makes programming easy Microcontroller (IC1) can be programmed in-circuit No messy wiring Next, we designed a small board to do the remote bit. It receives codes from any universal remote control and also provides an LCD readout big enough for MP3 track data. Plug it into a free serial port on your PC (or even build it right into your PC) and you’ve got a mean MP3 machine! This month, we describe the hardware part of the project. Next month, we’ll look at the Windows-based software, including Winamp and the control software that makes it all work as an MP3 player. The hardware – it ain’t hard! The brains of our little project is an AT90S2313 microcontroller chip from Atmel. We’ve chosen this particular microcontroller because it has plenty Fig.1: an Atmel AT90S2313-4P microcontroller (IC1) does most of the work in the circuit. It outputs control signals to a MAX232 RS232 receiver/driver IC (IC4), which in turn driver the serial port of your PC. IC3 is the IR receiver chip. www.siliconchip.com.au September 2001  25 Table.1: all the characters that can be displayed by the LCD module, along with their respective ASCII codes. characters received from the serial input are displayed on the LCD. In addition to displaying the usual ASCII characters (listed in Table 1), the program (or firmware) in the microcontroller allows our little board to recognise a number of “control” codes. If you’ve worked with ASCII before, you’ll know that the first 32 bytes of the character set are used as “control” codes – they’re not displayable and are intended solely for, strangely enough, control purposes. Using control codes, the programmer can change the cursor type, position the cursor, clear the display, and so forth. Table 2 lists all the control codes our project supports. Two codes in the table require further explanation. The first is the cursor positioning code, Ctrl-P. Unlike other control codes that are just one byte in length, to set the cursor position you need to send two bytes – Ctrl-P (16) followed by the required position (0 = first position of first line, 31 = last position of second line) plus an offset of 64. For example, to position the cursor at the beginning of the second line, you would send 16 and then 80 (16 + 64). The second code of interest is Ctrl-[, also known as “escape”. This code is used as the prefix for functions that require more than a single byte. Typically, a character identifying the function, then one or more characters containing the relevant parameters follows the escape code. This is known as an escape sequence. Our project defines just one escape sequence, which we’ve used to program the custom LCD characters – we’ll look at how these work a little later. The IR receiver of memory and runs fast enough to be able to handle all the tasks that we’ve thrown at it. What’s a microcontroller? Put simply, it’s a microcomputer integrated with a bunch of useful devices that makes interfacing to things like our LCD and infrared receiver really easy. In short, the microcontroller connects the LCD and infrared receiver to the outside world via a simple 4-wire serial interface. For our MP3 Jukebox project, the outside world is the serial port on a PC but it could just as easily be any microcontroller or computer 26  Silicon Chip project (see our Basic Stamp example later). The whole lot fits on a PC board not much bigger than the LCD module itself and is easily mounted behind any flat panel. As you can see from our photos, we’ve mounted ours behind a drive-bay blanking plate on a standard ATX PC computer case. So what can it do? Well, let’s look at the display part first. The liquid crystal display The display part functions as a simple serial terminal, meaning that This project differs from past infrared remote control projects described in Silicon Chip in that it doesn’t require a purpose-built transmitter. It works with most off-the-shelf universal transmitters, like the one you’re probably already using with your TV and VCR! Why do we need a different remote control for every new piece of equipment we buy anyway? Simply because there is no single remote control standard in use for consumer equipment. Many households have at least two (usually more) remote www.siliconchip.com.au The completed IR receiver & LCD module is attached to a modified drive-bay blanking plate and simply clips into the front of the PC. The cable from the PC board is then plugged into a serial port on the PC’s motherboard. controls, while some have opted for a “universal” unit that can be set up to work with equipment from different manufacturers. Naturally, we chose a “standard” that is probably supported by all universal remotes. This is the RC5 system, developed by Philips and in wide use throughout Europe. If you want to know a little about the workings of the RC5 system, then refer to the accompanying panel: “The RC5 Remote Control Specification”. To prove our system, we obtained two completely different universal remotes; one from Jaycar Electronics (model BC-3000, Cat AR-1710) and one from Coles Supermarket (Remote Master brand). When selecting a remote, you need to make sure that it has all the keys you would typically use to control a VCR or CD player (play, fast-forward, rewind, etc), as these aren’t included on the simpler TV-only models. Another important consideration is the number and type of devices it can control. If you only intend to use the remote for this project, then all you need is support for “VCR” or “CD” control. If, however, you want to use the same remote for other equipment, then you need to make sure that it will accommodate all intended devices. Our MP3 player can masquerade as a VCR or CD player, so in most cases you will be able to work it in with www.siliconchip.com.au what you already have. An exception to this would be if you already have a Philips brand VCR and a Philips brand CD player – a fairly unlikely (and in our case, unlucky) situation. To reliably receive data from one of these infrared transmitters, we need quite a bit of electronics, specifically an IR diode, amplifier, limiter, band­ pass filter and demodulator. Thankfully, all of these circuits are available in a single IC package. Jaycar Electronics has just what we are looking for in their ZD-1952 IR receiver IC, while Dick Smith Electronics has the Z1955. The output from this IC is the recovered digital signal, which we pipe directly into the microcontroller chip for decoding. After successfully decoding, the microcontroller flashes the “received” LED and sends the codes out the serial transmit line. To maintain data integrity, the codes are packaged with a couple of extra bytes, as follows: Byte 1 – Start byte (254) Byte 2 – Control bit (bit 7) + System    address (bits 4-0) Byte 3 – Command (bits 5-0) Byte 4 – Checksum of bytes 2 & 3 The start byte serves as a simple synchroniser, indicating the start of incoming data. The second and third bytes are the expected address and Table 2: Display Control Codes Code Ctrl-<at> Ctrl-A Ctrl-D Ctrl-E Ctrl-F Ctrl-H Ctrl-I Ctrl-J Ctrl-K Ctrl-L Ctrl-M Ctrl-P Ctrl-S Ctrl-T Ctrl-[ ASCII 00 01 04 05 06 08 09 10 11 12 13 16 19 20 27 HEX 00 01 04 05 06 08 09 0A 0B 0C 0D 10 13 14 1E Function Null (ignored) Home cursor Hide cursor Underline cursor Blinking block cursor Backspace Horizontal tab Linefeed (cursor down one line) Vertical tab (cursor up one line) Formfeed (clear screen) Carriage return (cursor to start of line) Set cursor position Auto-scroll on Auto-scroll off Escape (start of multi-byte instruction) September 2001  27 command codes. The fourth byte allows simple verification of the previous two bytes. If bytes 2, 3 and 4 are added together (modulus 256), then the result should always be zero. Construction A number of components in this project are static sensitive and should be treated accordingly. This applies particularly to the LCD module and IC1, the microcontroller. Wear a properly earthed anti-static wrist strap and use a soldering iron with an earthed tip during the following steps. All parts, including the LCD module, are mounted on a single PC board measuring 115 x 36mm. Referring to the overlay diagram (Fig.2), begin by installing the 9 tinned copper wire links, taking care to keep the links as straight as possible, as many of them will pass quite close to component leads. Next, install all the resistors, diode D1, and then the socket for IC1. The crystal (X1) can be installed next. Its leads should be bent at 90° about 2mm from the body so that they slip easily into their holes with the package lying flat against the PC board. Before soldering, make sure that you can just see the hole in the PC board at the top edge of the crystal. You need to use a short length of tinned copper wire to solder the body of the crystal to the pad underneath at this point. Next, install IC2, S1, VR1, CON1 & CON3. Note: CON1 is option­al; it isn’t needed if you have a pre-programmed microcontroller (IC1). Fig.2: the assembly details for the PC board. The body of the crystal (X1) is anchored to an earth track on the board using tinned copper wire. Fig.3: install the 5V regulator on the copper side of the board, as shown here (see also Fig.5). Fig.4: this is the full-size etching pattern for the PC board. This view shows the fully assembled PC board, prior to mounting the LCD module. The LCD module plugs into a 16-way header socket and is secured using 12mm spacers and machine screws. This photo shows how the 5V regulator is installed on the back of the board. 28  Silicon Chip www.siliconchip.com.au Now flip the board over and install REG1 on the copper side, following the mounting details shown in Fig.5. The insulator is necessary to prevent the tab of the regulator shorting out the tracks that pass underneath. Solder the regulator’s leads and flip the board over again. You will note that the regulator’s leads protrude through the top (component) side – cut these off flush with the surface of the board. Now we can install all the capacitors. Take special care with the five 10µF electrolytic capacitors. As you can see from the photos, they need to have their leads bent at 90° (about 2mm from the body) so that they lie flat against the PC board. These are polarised components – it is important which “way around” they’re installed, and getting it wrong on this board is dead easy! CON2 and the sockets for LED1 and IC3 can be installed next. We’ve socketed both LED1 and IC3 using part of the 40-pin single row header socket, so begin by cutting down the header socket into one 16-pin length, one 3-pin length and one 2-pin length. Use a sharp utility knife, and watch the pinkies! Install your newly-fashioned sockets into their respective positions, making sure that they are seated squarely against the PC board before soldering. We won’t plug in LED1 or IC3 just yet, because we need to fit the LCD module first to get height measurements. Note that we haven’t installed IC1 or IC4 yet either (tempting, isn’t it?). We need to apply power first and check that the +5V rail is OK. To do this, you’ll need to make up the power/data cable, using Fig.6 as a guide. Hook up the cable and apply power. If you don’t want to power the unit from your PC just yet, then any DC power source capable of supplying between about 8-12V DC at 100mA will do the job. Using a digital multimeter, measure between pins 10 and 20 of the IC1 socket. You meter should read 5V ±0.25V. If all is OK, remove power and install IC1 and IC4. Mounting the LCD module. Now we’re making progress! First, we need to install the header pins along the top edge of the LCD module. It’s important that the pins are inserted on the correct side of the board (see photos) – once they’re soldered in, www.siliconchip.com.au Fig.5: the mounting details for the 7805 regulator. It must be isolated from the copper on the PC board using an insulating pad. they’re very difficult to remove! Using side-cutters or a sharp knife, separate a 16-pin section (for modules with backlighting) or 14-pin section (for modules without backlighting) from the 40-pin single row header. Insert it on the bottom side of the LCD module and solder on the top (display) side. Ensure that the entire row of pins is seated squarely (sitting at 90° to the PC board) before soldering. Now plug the module into CON2 and secure to the main PC board with the four 12mm untapped spacers and M2.5 screws and nuts. You will note that the header doesn’t quite go all the way home – it sits about 1mm proud of the socket edge. This is perfectly acceptable, as the socket contacts have already done their job. Don’t fit washers under the nuts or screw heads, as they may short out nearby tracks. By the way, we’ve specified a particular LCD module from Dick Smith Electronics as not all modules have identical mounting hole or connector positions. In other words, you may have difficulties if you try to fit a module from a different source. The final step is installing LED1 and IC3, the IR receiver chip. As you can see from the photos, we have not plugged these components directly into their sockets. Rather, to ensure reliable mating to the socket contacts, we’ve soldered them to header pins first. Separate one 2-pin length and one 3-pin length from the remaining portion of the single row header for the LED and IR receiver. Before soldering them to the header pins, you might find it easier to prepare the front panel first so that you can accurately determine how much lead length will be required. Bolting it up An easy way to get everything to fit nicely up front is to photocopy the template in Fig.7, cut it out and tape it on to the panel. Use a sharp knife to mark the display cutout outline, and a centre punch to mark the hole positions for drilling. Four long spacers are used to mount the assembly behind the panel, so lets fit these next. Slip an M3 x 10mm screw into one of the corner holes on the PC board from the copper side. If your LCD module has backlighting, it is 4.5mm “thicker” than ones that don’t, so install two M3 washers and an M3 nut to provide extra mounting depth. Finish with a 20mm tapped spacer and then repeat the above for Fig.6: how to wire up your cable. If you’re installing it in your PC, then allow about 200mm for the power cable and about 700mm for the data cable, depending on the size of your case. September 2001  29 Fig.7: the is the drilling and cutting template for the drive-bay blanking plate. Note that the two IR sensors specified in the parts list require different hole sizes. Fig.8: this drawing shows how the LCD module is mounted. Note how the leads of the IR receiver (IC3) are bent, so that it fits neatly against the front panel. Make sure that the LED leads cannot come into contact with the IR receiver leads. the other three corners. Invert the works on a flat surface (LCD module and spacers facing down) and check that no light is visible between the end of the spacers and the flat surface. In other words, the spacers should be equal to or slightly higher than the surface of the LCD module. If not, then add washers as necessary. This is important because no pressure Fig.9: the LCD module has eight user-definable characters. Each pixel row translates to one byte, with a total of eight bytes required to define one character. Here we show how a “left arrow” character might be defined. should be applied to the front of the LCD module when the assembly is bolted home. With the assembly complete, you can trial-fit it to the front panel in order to gauge the length of the LED and IR receiver leads. The LED leads need to be long enough so that it protrudes through the panel, but not so long that its shoulder contacts the inside of the panel surface when installed. The IR receiver needs to be bent over at 90°, with its main body mass flush with the inside panel surface. Fig.8 shows how this is done. Take your time with this step, as it’s easy to overstress the leads. The IR lens (the “bump”) should actually slip inside the hole that you’ve drilled in the panel, with plenty of clearance all round. Once you’re satisfied, trim to size and solder to the header pins. Testing the LCD display Hook up the cable to a free serial port on your PC and connect a suitable power source. If you’ve made the cable as per our diagram, then obviously you’ll need access to an unused disk drive power connector from inside the PC case. If all your PC’s power connectors are already in use, you can purchase a “splitter” cable to fix the problem. These are available from DSE (cat X-2604), Jaycar (cat PL-0750) and most other computer suppliers. I’m assuming you’re running Windows 95, 98, ME, NT or 2000, and that The pin header is soldered to the LCD module as shown in the above photograph. The photo at left shows how the LED and IR receiver are mounted on header pins on the main board and plugged into matching header sockets. 30  Silicon Chip www.siliconchip.com.au The completed module is attached to the drive-bay blank using 20mm tapped spacers plus extra M3 nuts and washers as necessary to ensure that the LCD sits flush with the front panel cutout. The drive-bay blanks were resprayed black and the computer case charcoal grey with yellow highlights, to improve the appearance. you have HyperTerminal installed. If you don’t have HyperTerminal installed, then you can install it from the original Windows CD via Control Panel -> Add/Remove Programs -> Windows Setup. You’ll find it in the “Communications” group. When you start HyperTerminal, you’ll be prompted for a name for the new connection. Enter whatever you like and click OK. The Connect to dialog box now appears. Click the down-arrow next to the Connect using box and select the appropriate COM port, then click OK. The COM port settings dialog appears next. The settings you require are as follows: Bits per second: 9600 Data bits: 8 Parity: None Stop bits: 1 Flow control: Hardware Now click on the OK button and you’re ready to go. As soon as power is applied, the start-up message “S ILICON C HIP ” should be displayed and you will be www.siliconchip.com.au able to see the glow of the LED back­ lighting. Characters that you type on the keyboard should appear verbatim on the display. You can also experiment with the various control codes. For example, to clear the display, hold down ‘Ctrl’ and press ‘L’. Testing the IR receiver Before you can test the IR receiver, you need to set up your remote control to suit. Universal remote controls are supplied with a long list of all the brands and types of equipment they support. For our application, you should select only “Philips” as the brand and either “VCR” or “CD” for the equipment type. You’ll probably find that more than one code is listed against each choice, with no further explanation. All you can do is try each code in the list until you find one that works. Following the supplied instructions, lock in the chosen code and then press the appropriate equipment button. For example, if you chose “VCR”, don’t forget to press the VCR button before proceeding! We found that VCR code 278 works well with the Jaycar BC-3000, while for the Remote Master we chose CD code 1065 (use device mode AUX). You’ll know you’ve found a code that works when you point the remote at the IR receiver, press a button (try a digit first) and the LED flashes in response. If you still have the serial connection active, you’ll note that “garbage” characters appear in the HyperTerminal window whenever you press a key on the remote. This is a great sign – it means that all is working to plan! What if it doesn’t work? In all cases, recheck the +5V supply rail. Next, check that the microcontroller’s reset signal on pin 1 is at a logic high (close to 5V) and if you have an oscilloscope, check that the crystal oscillator is oscillating. Does the LCD display a message at power on? If not, check for shorts between pins at CON2 and using the circuit and overlay diagrams as a reference, do a continuity test between the pins on the LCD and the associated pins on the microcontroller. September 2001  31 Listing 1 '{$STAMP BS1} symbol S_IN = 6 'serial data input pin symbol S_OUT = 7 'serial data output pin symbol SYS_CODE = B0 'save system code here symbol CMD_CODE = B1 'save command code here pause 500 'wait for display to initialise ' Clear LCD screen and display message serout S_OUT,N2400,(12,“IR Receive Test”) loop: ' Wait until start of record received ($FE), then save next 2 bytes serin S_IN,N2400,($FE),SYS_CODE,CMD_CODE ' Display the received IR codes on the LCD serout S_OUT,N2400,(12,“Sys Code = ”,#SYS_CODE) serout S_OUT,N2400,(10,13,“Cmd Code = ”,#CMD_CODE) goto loop Listing 2 DEFINT A-Z CLS : PRINT PRINT “Custom character demo for Silicon Chip LCD Display” ' Set up COM port (change COMx number to suit your system). OPEN “COM2:9600,N,8,1,CD0,CS0,DS0,OP0” FOR OUTPUT AS #1 ' Write the bit patterns (from the DATA statements below) ' into the LCD’s CG RAM. FOR Char = 0 TO 2 'define custom chars 0, 1 & 2 CharNum$ = LTRIM$(RTRIM$(STR$(Char))) 'trim off Qbasic’s spaces PRINT #1, CHR$(27); “D”; CharNum$; 'send ESC D and character number FOR Row = 1 TO 8 'each char. consists of 8 rows READ CharBits 'get next bit pattern from data PRINT #1, CHR$(CharBits); 'write to LCD NEXT Row 'do all 8 rows for this character NEXT Char 'do next character PRINT #1, CHR$(12); “NEW CHARACTERS:” PRINT #1, CHR$(16); CHR$(16 + 64); 'cursor to start of second line PRINT #1, CHR$(0 + 128); CHR$(1 + 128); CHR$(2 + 128) 'show custom ' Custom character bit patterns follow. ' OK symbol DATA 8,20,20,8,5,6,5,5 ' locked symbol DATA 14,17,17,31,27,27,31,0 ' unlocked symbol DATA 14,16,16,31,27,27,31,0 If the LCD appears to be working but characters are not displayed when you type in HyperTerminal, then you can do a complete line loopback that will verify your cable as well as the RS232 receiver/transmitter chip (IC4). To do this, remove the LCD, unplug the microcontroller (IC1) and insert a fine wire link between pins 2 & 3 of the microcontroller socket and another link between pins 7 & 10. Leave out the LCD module (and IC1, of course!) and apply power. Now any keys you type should be looped right back and displayed in the HyperTerminal window. So the display and serial input works but the IR receiver doesn’t? First, check that the LED lights when you press the switch (S1). Next, check that you have installed the receiver chip (IC3) correctly, with pin 1 aligned as shown on the circuit and overlay diagrams (and photos). The output from this chip is idle high, going low when infrared light modulated around the 38kHz mark is received. If possible, try a different remote control, set up as detailed above. Got other uses in mind? Although this project is intended for our MP3 Jukebox, it would be equally at home as an extension to just about any computer or microcontroller project that requires an intelligent serial LCD readout and/or an IR receiver. Perhaps an example is in order. Fig.10 shows how to connect up to a Basic Stamp 1. Listing 1 shows just how easy it is to drive, even with the Basic Stamp’s limited resources. This short program waits for a key press on the remote and then writes the received system and command bytes back to the LCD – an easy way to check Fig.10: this project is eminently suitable as an add-on to a variety of other micro projects. Here’s how to wire it up to the Basic Stamp-1C. This model Stamp doesn’t have a true RS232 serial interface, so the resistors are included to provide protection for the I/O port pins. (The Basic Stamp-1C is available from Dick Smith Electronics). 32  Silicon Chip www.siliconchip.com.au The RC5 Remote Control Specification H AVE YOU EVER wondered how it is possible to control multiple pieces of equipment in the same room with just one remote? Well, all remote control systems that we know of use a method of addressing that separates equipment into generic groups. TVs, VCRs and CD players, for example, represent three such groups. In the RC5 specification, there are a total of 32 addressable groups, each with 64 possible commands. If you do the sums, this means that 2048 unique commands (or “messages”) are supported. Each message in the RC5 coding method is composed of a 14-bit serial stream. A message consists of four parts: • Start part – 1.5 bits (2 x logic “1”) • Control part – 1 bit • System part – 5 bits • Command part – 6 bits The start bits give the receiver AGC time to “lock on” to the incoming data. The control bit, also called the toggle bit, is simply a flag to indicate whether the following code is new or repeated. If a new key is pressed, the control bit toggles (changes state) from it’s previous value, otherwise it remains the same. The system bits are the equipment address, as described above. Finally, the command bits are the code for the actual key pressed. Table 3 lists all of the equipment addresses. Table 4 lists just a few of the possible 64 commands and the key functions that they relate to. Determining the code transmitted for any key on your remote is very easy, the codes assigned to each key on the remote. Advanced features The default baud rate is 9600 bits/ sec, but can be changed to either 4800 or 2400 by entering setup mode. To enter setup mode, press and hold down switch S1, then apply power, releasing the switch when the start-up message appears. Immediately the switch is released, a message appears displaying the firmware revision, followed by the www.siliconchip.com.au Table 3: RC5 Equipment Addresses Address 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27-31 Equipment TV1 TV2 Videotext TV1 & TV2 expansion Laser video player VCR1 VCR2 Reserved SAT1 VCR1 & VCR2 expansion SAT2 Reserved CD video Reserved CD photo Reserved Audio preamp 1 Tuner Cassette recorder Audio preamp 2 CD Audio rack Audio satellite receiver DCC recorder Reserved Reserved Writable CD Reserved as we will see in our software examples. On the physical level, data is transmitted using bi-phase (also known as Manchester) encoding. A logic one is represented by a zero-to-one transition at 1/2-bit time, whereas a logic zero is represented by a one-tozero transition. One-bit time is approx. prompt “Set baud rate?”. If you press the switch again within four seconds, the current baud rate is displayed. You can then cycle through all three possible baud rate values in turn, until you find the one that you require. If you don’t press the switch within four seconds, then the display clears and the last value displayed becomes the new baud rate. Don’t worry if you weren’t quick enough the first time; just repeat the procedure! If you don’t press the switch at the Table 4: RC5 Keycodes & Functions Code 0 1 2 3 4 5 6 7 8 9 10 12 13 16 17 32 33 35 39 48 50 52 53 54 55 Function 0 1 2 3 4 5 6 7 8 9 10+ Standby Mute Volume Volume + Ch/prog + Ch/prog 20+ Tint/hue + Pause Rewind Fast-forward Play Stop Record 1.778ms, so a complete message is 24.889ms long, with messages repeated at a minimum of 114ms intervals. To reduce interference from other light sources, data is transmitted on a 36kHz carrier. We found that the Jaycar ZD-1952 infrared receiver IC worked well with a number of different remote controls that we tried, even though its centre frequency is specified as 37.9kHz. “Set baud rate?” prompt, then “Down­ load EEPROM?” appears after a few seconds. If you press the switch at this point, the message changes to “Waiting for data”. As you might have deduced from the message, this feature allows you to update the contents of the microcontroller's EEPROM. In order to make use of this feature, you need at least a little knowledge of microcontroller programming. The AT90S2323 has 128 bytes of EEPROM and our firmware makes use September 2001  33 Parts List For IR Remote Receiver + LCD Display 1 PC board, code 07109011, 115 x 36mm 1 LCD module, 16 character x 2 line with LED backlight* (DSE Cat Z-4172) -OR1 LCD module, 16 character x 2 line (DSE Cat Z-4170). * Note: LCD module with backlighting recommended 1 10-pin dual row header (CON 1) (optional, see text) 1 40-pin single row header socket (CON 2) (Altronics Cat P-5390) 1 40-pin single row header (for LCD module) (Altronics Cat P-5430) 1 90° PC-mount 6-pin header (CON3) (Altronics Cat P-5516) 1 6-pin header socket to suit above (Altronics cat P-5476) 1 SPST tactile membrane switch (S1) (Altronics Cat S-1120) 1 20-pin IC socket (machined pin type) 1 4MHz crystal (HC49 package, parallel resonant) (X1) 1 4-pin disk drive power connector (socket, with male pins) (DSE Cat. P-5120) 1 9-pin female ‘D’ connector with backshell 1 Universal IR Remote Control (eg, Jaycar Cat. AR-1710) Semiconductors 1 AT90S2313-4P microcontroller (IC1), programmed with IRRLCD.HEX & IRRLCD.EEP 1 MC34064P-5 under-voltage sensor (IC2) (Altronics Cat. Z-7252) of a fair slice of this to store parameters such as the baud rate, power-on message and custom LCD characters. If you’re not daunted by the innards of an assembler file, then have a look at the IRREE.ASM file included in the software download – you can open it with any text editor. This file defines the layout of the data stored in the microcontroller's EEPROM. You can make changes to this file, reassemble it (using any Atmel AVR assembler) and download the resultant IRREE.EEP hex file using the above setup mode feature. To do this, enter setup mode, and get the “Waiting for data” message on the 34  Silicon Chip 1 IR receiver (IC3) (Jaycar Cat. ZD-1952; DSE Cat. Z-1955) 1 MAX232 RS232 receiver/driver (IC4) 1 LM7805 5V regulator (REG1) 1 3mm high efficiency red LED (LED1) 1 1N4001 1A diode (D1) Capacitors 1 100µF 25V PC electrolytic 5 10µF 16V PC electrolytic 3 0.1µF 50V monolithic ceramic 2 27pF 50V ceramic disc Resistors (0.25W, 1%) 1 10kΩ 1 4.7kΩ 1 180Ω 1 22Ω 1 10kΩ miniature horizontal trimpot (VR1) Miscellaneous 4 12mm untapped spacers (5mm max. O.D.) 4 M3 x 20mm tapped spacers 4 M2.5 x 20mm screws 4 M2.5 nuts 5 M3 x 6mm c/sunk head screws 4 M3 x 10mm cheese head screws 4 M3 nuts 13 M3 washers 1 TO-220 silicone or mica insulating washer 180mm (approx.) tinned copper wire for links 4-core data cable for serial port connection Light-duty hookup wire display as described above. With the board connected to your PC, open HyperTerminal (configured as described earlier) and send the new IRREE.EEP file out the designated serial port using text only file transfer. If the transfer is successful, then the LCD should display “Download OK!”, otherwise an error message will appear. If nothing happens, then the data was either not received or was garbled. Defining custom characters In addition to the standard character set (see Table 1), the LCD module has eight custom-character slots. These can be really handy, as we found when we needed the classic “play”, “stop” and “pause” symbols for our MP3 Jukebox. LCD characters are composed on a 5 x 8 pixel bitmap. Each character row is defined in one byte, with the upper, unused bits set to zero. Fig.9 gives an example of the values needed to define a single character. Once you know the bit patterns for your new character, send them to the LCD with the following escape sequence: ESC D n B0 B1 B2 B3 B4 B5 B6 B7 where ‘ESC’ identifies the start of a multi-byte instruction, ‘D’ indicates that this is a custom character definition, ‘n’ is the character number (from 0-7), and B0-B7 are the byte patterns that define the custom character. Using the values from our example, the actual string to transmit (in decimal notation) would be: 27 68 00 00 04 08 31 08 04 00 00 The microcontroller maps custom characters to ASCII 128-136, so to display a custom character, use its num­ber (0-7) plus an offset of 128. Listing.2 shows how it all works in a real program. This example, written in QBasic, defines the first three custom character slots and then displays the results. Programming the micro If you purchased this project as a kit, then the microcontroller (IC1) will have been pre-programmed and you can ignore the following information. If not, then we have made provisions for programming the chip in-circuit. In common with many recent microcontrollers, the AT90S2313’s flash program memory and EEPROM data memory can be electrically erased and programmed while in-circuit. Atmel has assigned alternate functions to three port pins for the task, which we’ve routed to CON1, the in-circuit serial programming (ISP) header. To use this feature, you need a free software package from Atmel called AVR ISP. You also need a simple adapter board that connects between your PC’s parallel port and CON1 on our board. We hope to describe this board next month. Finally, the microcontroller program files (including all the source code) are available for free download from the Silicon Chip website at SC www.siliconchip.com.au www.siliconchip.com.au SILICON CHIP WebLINK How many times have you wanted to access a company’s website but cannot remember their site name? Here's an exciting new concept from SILICON CHIP: you can access any of these organisations instantly by going to the SILICON CHIP website (www.siliconchip.com.au), clicking on WebLINK and then on the website graphic of the company you’re looking for. It’s that simple. No longer do you have to wade through search engines or look through pages of indexes – just point’n’click and the site you want will open! Your company or business can be a part of SILICON CHIP’s WebLINK. For one low rate you receive a printed entry each month on the SILICON CHIP WebLINK page with your home page graphic, company name, phone, fax and site details plus up to 50 words of description– and this is repeated on the WebLINK page on the SILICON CHIP website with the link of your choice active. Get those extra hits on your site from the right people in the electronics industry – the people who make decisions to buy your products. 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Wide bandwidth, high output and unconditional stability with hum-cancelling circuitry, front-panel video gain and cable eq adjustments. 240V AC, 120V AC or 24V DC High resolution 1in/2out VGA splitter. Comes with 1.5m HQ cable and 12V supply. Custom-length HQ VGA cables also available. Check our NEW website for latest prices and MONTHLY SPECIALS www.questronix.com.au Email: questav<at>questronix.com.au Video Processors, Colour Correctors, Stabilisers, TBC’s, Converters, etc. QUESTRONIX JED designs and manufactures a range of single board computers (based on Wilke Tiger and Atmel AVR), as well as LCD displays and analog and digital I/O for PCs and controllers. JED also makes a PC PROM programmer and RS232/RS485 converters. Jed Microprocessors Pty Ltd Tel: (03) 9762 3588 Fax: (03) 9762 5499 WebLINK: www.jedmicro.com.au VGS2 Graphics Splitter NEW! 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Wiltronics Pty Ltd Tel: (03) 9762 3588 Fax: (03) 9762 5499 WebLINK: www.wiltronics.com.au Programmable arms, walkers and mobiles from robot-Oz “Hexapod 1” BASIC Stamps® and ® Muscle Wire www.robotoz.com.au Ph: (08) 9370 3456 www.siliconchip.com.au www.siliconchip.com.au Fax: (08) 9370 2323 EPTEMBER2001  35 2001  35 SSeptember PC CONTROLLED Everyone, it seems, has an old computer, unused and unloved, gathering dust somewhere. Wouldn’t you like to do something useful with it, like controlling external devices? This project has both the hardware and software to do exactly that – and it will work on anything from a 386 up! Concept, hardware and software design by Trent Jackson Words by Ross Tester I goes. Just remember, though, that this nitially, this project was designed is a mains-powered and mains-conto turn a swimming pool filter trolling device and the circuit “floats” pump on and off at appropriate at full mains potential at all times. times. Sure, you can buy a pretty cheap mechanical or electronic timer There are certain practices and proto do that but with an old 486 lying cedures which must be followed for idle and the possibility – no, make your own safety and that of anyone else that probability – of controlling a lot using the device (not to mention the more than a pool pump, I thought, longevity of your computer!). Most of why not? all, be extremely cautious when testing As it turned out, the hardware to do or servicing the circuit with the cover the job is relatively simple and cheap – there are only about twenty components required FEATURES to give a pretty nifty circuit. build  Low cost, easy to The software, though, is a little more complicated – but as I tection  Fuse and surge pro have already done that part for ion you, all you need to do is build  Full optical isolat the control box, dust off that old ction  System enable fun computer, fire it up and load the itching software.  Efficient relay sw It uses the parallel (printer)  Precision timing port of just about any PC from, r events say, 386 vintage onwards. It op Control up to fou erates under good, old fashioned er settings  Save and open tim DOS (remember that?) – in fact, I wouldn’t recommend it being run under Windoze. off. To be absolutely safe, I’d suggest The hardware you do all your testing with a 12V battery powering it. At SILICON CHIP There is nothing too difficult to either we like our readers and want to keep comprehend or build as far as hardware all of them alive! We’ll show you how to hook in a 12V supply later on. Speaking of safety, the circuit features fuse and surge protection and has full electrical isolation (by means of an optocoupler) between the mains and the connection to your computer. Now, let’s look at the block diagram, Fig.1, in conjunction with the circuit diagram, Fig. 2. The first thing you will note is that there is no transformer. The 240V mains is applied via a 10A fuse (for protection against catastrophic failure) and a 275V varistor (to suppress any mains-borne spikes). A capacitor across the mains also assists in filtering out any noise. Next there is an AC current limiter consisting of a pair of parallel capacitors which together add up to about 1µF. From first principles, we know that series capacitors in an AC circuit offer resistance (or more correctly impedance) to current flow. This is expressed by the formula XC = 1/2π f C, where XC is in Ohms, f is the frequency in Hz and C is the THIS IS A MAINS-POWERED DEVICE AND THE CIRCUITRY IS LIVE (240V AC) WHILE EVER POWER IS CONNECTED, EVEN IF THERE IS NO OUTPUT VOLTAGE. DO NOT ATTEMPT TO BUILD THIS PROJECT IF YOU ARE NOT ENTIRELY FAMILIAR WITH MAINS WIRING PRACTICES AND CONSTRUCTION TECHNIQUES. 36  Silicon Chip www.siliconchip.com.au D MAINS SWITCH capacitance in farads. Therefore, at 50Hz, the two capacitors are going to present an impedance of about 3.2kΩ. From Ohm’s law (I=E/R), we can then deduce that the current will be limited to 240V/3200Ω or about 75mA. The 47Ω resistor following the series capacitors can be all but ignored for the purpose of this equation – its job is to limit the inrush current which would otherwise occur at switch-on. The four diodes (D1-D4) form a bridge rectifier across the 240V AC mains, resulting in a pulsating DC voltage output of about 340V (240 x 1.414). Zener diode ZD1 is connected as a shunt regulator across this supply, clamping it to around 12V DC. The two capacitors (C3 and C4) provide further smoothing, resulting in a relatively well-regulated 12V DC supply for the rest of the circuit. A red LED across the 12V supply shows that power is applied. So far, all we’ve looked at is the power supply – but there is not much else to it! Turning back to the other input, www.siliconchip.com.au that from the computer, we see that two pins, Data 1 and Strobe, of the parallel port, provide the signal drive for the switch. Under software control, when Data 1 goes high and the Strobe goes low, D5 and D6 are both forward biased, lighting the LED inside the optocoupler (the 180Ω series resistor limits current from the parallel port to safe levels). As you can see from this, there is no electrical connection whatsoever between the computer and this circuit. The optocoupler specified, SFH601-3, has been chosen because of its high isolation. Lower rated optocouplers should not be used. When the LED in the optocoupler lights, the transistor in the opto-coupler Fig.1: the block diagram of the PC-controlled mains switch shows that there is complete isolation between the mains and the PC. September 2001  37 PC CONTROLLED MAINS SWITCH WARNING: THE MAJORITY OF THIS CIRCUIT OPERATES AT 240VAC! N  E  LED2 1.2k ZD1 12V 5W E B C 1000F 25V BC548 0.1F SC 2001 LED1 POWER 1.2k ½OPTO1 SFH601-3  RLY1 10 D5 1N4007 E CONTACT WITH ANY PART OF THIS CIRCUIT WHILE CONNECTED TO THE 240VAC MAINS SUPPLY COULD KILL YOU! 240VAC OUTLET A RLY1 250VAC Q1 BC548 C B 4.7k 4 5 D1 - D4 4 x 1N4007 ½OPTO1 SFH601-3 1  2 PARALLEL PORT CONNECTOR PIN NUMBERS. *NUMBERS SHOWN INDICATE 0.1F 250VAC CLASS 'X2' 20 12 13 11 10 PORT TO PC *PARALLEL 1 3 100 D7 1N914 180 E 240VAC INPUT N D6 1N914 V1 V275LA20A 275VAC A F1 10A (MAX) 250VAC 100k ½ W 0.47F 250VAC CLASS 'X2' 0.47F 250VAC CLASS 'X2' 47 1W K A LED The software Fig. 2: the complete circuit diagram of the PC-Controlled Mains Switch. 38  Silicon Chip conducts. This transistor is connected in “Darlington” fashion to Q1 which is then turned on. Current flows from Q1’s collector to emitter, through a 10Ω resistor and then through the relay coil, pulling it in and closing the 240V active circuit. Therefore, whatever is connected turns on. At the same time, the green LED between Q1’s emitter and ground also turns on to give indication that 240V power is available. The reverse-biased diode across the relay coil doesn’t normally conduct. Its purpose is to protect Q1 when the optocoupler turns off and the relay de-energises. This can generate a quite high voltage pulse which might destroy Q1; when the relay de-energises the diode becomes forward biased, safely bleeding the pulse away. Finally, you will note that all 4-bit inputs to the PC parallel port are connected together and tied low, to pin 20. This is essential for the port to operate as we intended. Incidentally, the port must be operated in the “ECP” mode, which can normally be set up via the computer’s CMOS setup. ECP, by the way, stands for Enhanced Capabilities Port. If you don’t know how to do this, refer to your computer’s manual (or perhaps you shouldn’t be attempting this project!). The software, PCMS.EXE, does the vast majority of the “work” – my philosophy is minimum hardware and maximum software! It is written in Q-BASIC and a zipped version can be downloaded from the SILICON CHIP website. As mentioned before, this should be run in DOS mode. While I have run it under Windows, it occasionally gets upset and freezes. You shouldn’t have this problem under DOS. The software will run without the controller hardware plugged in, so you can get a feel for its operation and features. There is a scrolling message at the bottom of the screen which tells you which keys to press for which operations. It’s also designed to be very user-friendly – once you’ve used it a couple of times you will get the hang of it. The heart of the program is the timer settings box. When you first run the program it will load up null settings www.siliconchip.com.au back and type over. (The backspace key will delete characters in the files box). Files box You can save current timer settings in a file and recall it later – press the F4 key to save your current settings and F5 to open any presaved settings. System box The current time and date, read from your PC’s real time clock, are displayed in the top two boxes. You cannot change these – you must go into your PC’s time and date setting procedure (via CMOS setup) to do this. The Port Address can be changed to match the port address of your computer’s parallel port. The default is H378; some computers have theirs at H278 but pressing the F1 key will toggle through the various addresses possible. If you have a valid port address, the port data (immediately underneath) should read between H120 and H148. Note that the port mode must first be set to ECP (enhanced capabilities port) mode via your CMOS setup. The “Device Enable” box is not controlled by the timers; you have to set The completed PC board with its connections to power, to the mains outlet (GPO), the front panel LEDs and to the computer parallel port. There were some minor differences between this photo and the final version shown below. (0’s) for each of the four programmable events. are entered in the format MM-DD-YY (eg, 19th September 2001 would be 00-19-01); times are in 24 hour format (8.15pm would be 20:15). To modify any setting, use the arrow keys (keypad) to move the flashing cursor to the unit you want changed and enter the new setting of the null setting. The backspace key does not delete – move the cursor Timer Settings box There are two modes. MX is the normal mode and can handle both dates and times. DX is the alternate mode, used when you want an event to occur on a daily basis (so no date input is needed) Dates GPO (REAR VIEW) E A CASE CASE LO EL /Y EN RE (G L RA UT NE ) UE (BL CORD GRIP GROMMET www.siliconchip.com.au 180 SOLDER RESISTOR ACROSS V1 D6 1.2k 10 4.7k 1.2k 100k Q1 D5 F1 10A (MAX) 250VAC 1 * * 3 OPTO1 SFH601-3 1 PIN NUMBER ON *PC PARALLEL PORT CONNECTOR 0.1 F 250VAC 0.47 F 250VAC 0.47 F 250VAC 0.1 F D3 25V (BROWN) 1000 F TIVE D2 D7 1N 4148 + ZD1 AC 47 1W D4 Fig.3: follow this component overlay and wiring diagram when building the project. Build and test the PC board first – but don’t put in the 5W Zener (ZD1) until after testing. DATA CABLE ISOLATED SECTION 4 x 1N4007 D1 V1 E TH AR N 1N 4148 250VAC MAINS CABLE CORD GRIP GROMMET ) W A LED1 K A LED2 1N4007 K RLY1 10A / 250VAC September 2001  39 Here’s what the software, PCMS.EXE, looks like on the screen. You can set the on and off times for up to four events as well as change various parameters as described in the text. Download the software from www.siliconchip.com.au this manually with the F2 key in order to enable the hardware. Finally, the “Device Status” box should automatically come up with a “connected” message if your port is functioning correctly and the hardware is connected. If the software has detected errors (eg, no hardware connected or a port malfunction of some sort) it will read unknown. The big box underneath the System box is a visual indication that everything is working as it should: when the timer turns the hardware on, the box changes from red to green and the message changes from “AC POWER IS OFF” to, surprise surprise, “AC POWER IS ON”. If you don’t like the background colour, toggle the F6 key. There are 16 different colours and styles to choose from – there must be something there you’ll like! we specify nylon types – if a nut works its way loose inside the case and shorts out something, you or your PC could disappear in a puff of blue smoke. As usual, start by visually checking the PC board to ensure there are no etching or drilling defects. Then commence assembly with the lowest profile components – resistors, varistor and diodes (ensure the diodes are the right way around!). At this stage, don’t fit the Zener diode because it will get upset with our checking procedure later. Next are the smaller capacitors (watch the polarity on the electrolytics), the IC and transistor (ditto) and the fuse clips. Some fuse clips have little lugs on them which will stop a fuse being inserted if they are back-tofront: check yours by inserting a fuse before soldering. All that’s left now are the larger capacitors and the relay. Now we are ready to move on to the wiring which Construction Before we start, another word of warning. Please ensure that you follow the construction method to the letter – we have gone to a great deal of trouble to ensure that the design is safe and construction methods echo that safety. For example, do not substitute standard metal bolts and nuts where 40  Silicon Chip The PC board is secured to the case lid with four nylon screws, as shown here. Each screw has a nylon nut on the inside acting as a spacer before the PC board is seated and secured with another nylon nut. www.siliconchip.com.au is where you have to be particularly careful to make sure nothing is wrong. The basic premise is that the wires need to be only as long as necessary to reach and not long enough to short to something else if for some reason they come adrift. Before you do that, though, you should prepare the jiffy box for the external components and wiring. A 6mm hole is required at each end (for the mains cable and the computer cable), each with a rubber grommet. The bottom of the box is used as the top (the lid becomes the base) and in this you will need two 5mm holes for the LEDs, two 3mm holes for the power outlet mounting screws and finally a 30mm hole for the back of the power outlet to poke through. All labels should now be glued to the box and left to dry. While that’s happening, go over your PC board assembly once more to make sure everything’s where it should be. It will be much more difficult to check it later. Prepare the red and green LEDs by soldering a 100mm length of 4-way rainbow cable to their respective legs. Note which legs are the anode and the cathode (the anode lead is the longer) and then cut both legs very short – say 3mm – and solder the rainbow cable to them leaving as much as the cable intact as you can. Then wrap the soldered joints in insulation tape so that no exposed legs or wire are visible. If necessary, put a piece of tape between the legs to ensure they don’t short. If you’ve now forgotten which leg was which, the cathodes are the ones adjacent to the flat on the LEDs! Write down the colours of 4-way rainbow cable which go to each leg, and which colours go to which colour LED. Fit LED mounting collars over them and push them through the bottom of the box. Lock them in place with a dab of silicone sealant, super glue, 5-minute Araldite or other suitable adhesive. Refer to the wiring diagram for the mains wiring and follow it exactly. Again, only make the leads as long as you need to. Remove the outer insulation from the three-wire mains lead to a length of 175mm. Cut off 100mm and put it aside – you’ll need this as mains hookup wire. Push the wires of the mains lead through the appropriate www.siliconchip.com.au Parts List – PC Controlled Mains Switch 1 PC board, 101 x 57mm, coded 10109011 1 plastic case (Jaycar HB6013 or equivalent) 1 mini switched power outlet (GPO) (HPM 787 or equivalent) 2 cord-grip grommets to suit cables used 2 3AG fuse clips, PC mounting with protective cover 1 10A 3AG fuse 1 SPST relay, 12V coil (220Ω) with 10A 240V-rated contacts (Jaycar SY-4050 or equivalent) 1 piece insulating material to suit – Elephantide or plastic (see text) 5 mini cable ties 6 M3 x 10mm nylon screws 10 M3 nylon nuts 6 spring washers 100mm length 4-way rainbow cable (colours unimportant) 2m length 240V 10A mains lead with moulded 3-pin-plug 2m parallel printer cable (D-25 plug) (without Centronics plug) OR 2m length 2-core shielded cable and 1 D-25 male plug Semiconductors 1 SFH601-3 optocoupler (OPTO1) (DSE Z9023 – do not substitute) 1 BC548 NPN transistor (Q1) 1 12V 5W Zener diode (ZD1) 1 275VAC Varistor (V1) 5 1N4007 power diodes (D1-D5) 2 1N914 signal diodes (D6, D7) 1 5mm red LED (LED1) 1 5mm green LED (LED2) Capacitors 1 1000µF 25VW PC mounting electrolytic 2 0.47µF 250V AC X2-class polyester 1 0.1µF 250V AC X2-class polyester 1 0.1µF MKT polyester Resistors (0.25W, 1%) 1 4.7kΩ 2 1.2kΩ 1 180Ω hole from the outside. You’ll need to push through much further than the end of the insulation – at least another 50mm or so, to give you enough room to attach the power outlet. Take the Neutral (blue) and Earth (green yellow) wires through the large hole in the box to the outside. Remove 15mm of insulation from both. The only connection to the Earth terminal of the power outlet (labeled “E” or perhaps with green or green/ (Code 474 or 470n) (Code 104 or 100n) (Code 104 or 100n) 1 100Ω 1 10Ω 1 47Ω 1W yellow marking) is the Earth wire. Bend the bare wire back on itself, push it into the terminal and tighten the grub screw. Ensure there is no exposed wire (especially tiny strands of wire). Now take that blue length of mains wire you cut off before and strip 15mm of insulation from it. Tightly twist this and the blue wire coming out of the box together and insert them into the Neutral terminal of the power outlet Resistor Colour Codes       No. 1 2 1 1 1 1 Value 4.7kΩ 1.2kΩ 180Ω 100Ω 47Ω 10Ω 4-Band Code (1%) yellow purple red brown brown red red brown brown grey brown brown brown black brown brown yellow purple black brown brown black black brown 5-Band Code (1%) yellow purble black brown brown brown red black brown brown brown grey black black brown brown black black black brown yellow purple black gold brown brown black black gold brown September 2001  41 (labeled “N” or perhaps with blue or black marking) and tighten the grub screw. Ensure there is no exposed wire nor strands of wire. Now take that brown length of mains wire you cut off before and strip 15mm of insulation from it. Twist the strands together, fold them back on themselves and insert the wire into the Active terminal of the power outlet (labeled “A”, perhaps with red or brown marking). Tighten the grub screw and ensure there is no exposed wire nor strands of wire. Push the power outlet down onto the box and secure it in place with two 3mm x 10mm nylon bolts and nuts (don’t use metal ones!) and spring washers (which should be metal). Tighten completely and check that the power outlet will not move around at all. Fig.4: wiring the D-25 (parallel port) plug which connects to your computer. We’re not going to connect the mains wiring to the board yet – that will come later after completion and testing. First we will solder the LED wiring (ie, the 4-wire rainbow cable) to the board in the positions shown. NOTE: a 100kΩ ½W resistor should be connected across the Varistor as shown in Figs.2 & 3, to safely discharge the X2 capacitors when power is switched off. Computer cable Now it’s time for the computer cable. In all probability, you’ll be using a “ratted” Centronics printer cable but if you have to make up a new one, that’s not too difficult using a standard D-25 male plug and backshell assembly and some 2-core shielded cable. See Fig.4 for the plug detail. This cable must be passed through the box in similar manner to the mains cable but to hold things together, a short length of heatshrink is first heated onto it. The essential thing about this cable is that none of the wires is long enough to reach the power outlet should one come adrift later. The distance from the side wall of the box to the closest point on the power outlet was 50mm so we cut our cable to 45mm. That makes it a tight job to solder to the PC board, but it can be done. Testing Front and rear close-up views of case. You will note that for safety there are no metal screws used – the warning on the back panel means what it says! You should not build this project if you are not experienced in mains wiring construction. 42  Silicon Chip As we said before, for safety’s sake you really should check the operation with a 12V battery. The easiest way to do this is with a pair of wires temporarily soldered to the back of the PC board across where the Zener would normally go – just watch the polarity. Apply 12V power and ensure that the red LED lights. The green LED should not light nor should you hear the relay click in. If OK, plug the D-25 connector into your computer’s parallel port and run the pcms.exe software (in DOS mode). Remember to set the port to ECP mode at boot-up. Following the processes outlined above, ensure that the software does indeed control the board as intended. You can check the relay operation with a multimeter. If all is OK, turn off power, disconnect from the computer and remove www.siliconchip.com.au   Own an EFI car? Want to get the best from it? You’ll find all you need to know in this publication       
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 September 2001  43  Same-size PC board pattern and labels for the back and front of the case. The labels should be glued on before final assembly. On the front panel, the largest hole is 40mm diameter, the LED holes are 5mm and the other two are 4mm. Use a copy of the label as a template for drilling the case. The PC board pattern and labels can be downloaded from www.siliconchip.com.au 44  Silicon Chip SILICON CHIP www.siliconchip.com.au OUTPUT ON POWER APPLIED PC CONTROLLED MAINS SWITCH All parts of this circuit have 240VAC applied even when the output is switched off. Contact with this voltage could be lethal: use extreme caution when servicing or testing this apparatus. WARNING Almost ready to close – these two photos more clearly show the wiring between the PC board and the power outlet on the front panel, and also the wiring to the LEDs and to the computer parallel port plug. At left is the sheet of insulation material, a piece of elephantide or similar, or it can be cut from a plastic sheet such as an ice-cream container. which is inserted between the PC board (component side) and the wiring to the power outlet. It’s just another bit of insurance should the “impossible to happen” happen – a wire works its way loose which could jeopardise the inherent safety built into the switch. www.siliconchip.com.au Another view of the almost-completed project, this time from above and with the insulation in place. Once again, note the use of nylon nuts and bolts – for safety reasons. the two wires you temporarily soldered to the back of the board and solder in the Zener diode (the right way around). Make sure you don’t leave any solder bridges or splashes. Mains wiring Follow the wiring diagram exactly. The brown wire from the power outlet solders to the centre of the PC board, the blue wire from the power outlet solders to the edge of the board and the brown wire from the mains lead also solders to the edge of the PC board. To complete, fit some form of insulating cover over the fuse. Final assembly It is important to fit cable ties to hold the various lengths of wiring together – this should ensure that wiring cannot move around in the event of something coming adrift. Cable ties must also be fitted to the mains cable and the parallel cable on the inside of the grommets to prevent the cables from being either pulled out or flexed unduly. Now the PC board must be secured to the case “lid” with nylon nuts and bolts. This again is not real easy given the fact that the wiring lengths have been kept short. But it can be done! First drill the case lid in the positions shown and fit a nylon bolt and nut to each of the holes. Tighten completely, then slide the PC board down onto the nuts and fit another nut to the top side. Ensure these are also tightened. Before screwing this assembly into the box, cut a piece of insulation material the size of the box with corners trimmed for the mounting pillars. This goes between the mains outlet and the PC board components. Elephantide has been traditionally used for this role; a piece of thin plastic (eg, cut from an ice-cream container) would serve as well. Slide this insulation into the box, push the PC board and lid assembly down on top of it and fit the four case screws. Your PC controlled switch is now finished and should work exactly the same way as when you tested it. NOTE: updated software for this project is available from: http://members.optushome.com.au/video1/macksprograms SC www.siliconchip.com.au September 2001  45 PRODUCT SHOWCASE Ethernet modules from Rabbit Semiconductor Rabbit Semiconductor has added two new Ethernet core modules to the popular RabbitCore product line. No bigger than a credit card, these modules include the high-performance Rabbit microprocessor, up to one megabyte of memory (flash and SRAM), an Ethernet interface and connector. In addition, the four serial ports, battery-backable clock, cold boot capability, a slave mode and up to 40 I/O lines make product design fast and economical. The Rabbit 2000 is an 8-bit microprocessor with a C-friendly instruction set, fast number crunching ability and features such a four serial ports, a slave port, remote bootstrap capability, advanced clocking options and glueless interfacing to both memory and I/O. With a clock speed up to 30MHz, the Rabbit 2000 outperforms alternative processors, making it a substitute for 16 and 32-bit processors at a much lower system cost. The Rabbit 2000 features an updated Z180 style architecture to allow 1-byte operation codes for new instructions. Existing Z180 assembly language can also be ported to the Rabbit 2000 with minimal change. New C-friendly instructions are included for fetching and storing 16-bit words located at a computed memory address or on the stack. New instructions perform fetches, stores, calls, returns and jumps over a full megabyte of address space. Memory access instructions can be turned into I/O access instructions by using a prefix. As a consequence, I/O access is faster and more flexible. The Rabbit 2000 has a special support feature for battery-backed RAM. In typical processors, a battery switchover circuit maintains at least 2V of supply to RAM and pulls the chip select line up to the same voltage as the battery. This method has a propagation delay as much as 20 nanoseconds. The Rabbit’s special battery backup feature allows chip select #1 to be always forced low under program control, thus avoiding clock slow down. A hardware memory write-protect feature protects battery-backed RAM and flash memory from inadvertent write operations. There are 40-plus I/O pins grouped in five 8-bit ports. Eight external programmable I/O interface signals can be configured as I/O chip selects, I/O write strobes, I/O read strobes and I/O read/write strobes. Standard I/O read and I/O write enable signals are also available. I/O devices can be directly connected to the I/O interfaces, and often without glue logic. Four asynchronous serial ports are on-chip. Two of the ports also have synchronous communication capability. The asynchronous ports operate at speeds up to 1/32 of the clock frequency, while synchronous mode allows baud rates up to 1/8th of the clock frequency. For further information on the Rabbit 2000 and the Ethernet core modules, contact the Australian distributor, Dominion Electronics or visit their website. Contact: Dominion Electronics Suite 201, 82 Christie St, St Leonards NSW 2065 Phone: (02) 9906 6988 Fax (02) 9906 7145 Website: www.dominion.net.au Jaycar opens its first Macarthur region store Jaycar Electronics newest store in Campbelltown, NSW will employ up to five local staff in a combination of full time and casual positions. Jaycar brings to Campbelltown many years of retail experience and a proven product range covering alarm systems, test equipment, video surveillance, car audio, electrical & electronic tools, wire, cable and accessories. Jaycar is also known for its extensive range of electronic hobbyist kits. Gary Johnston, Managing Director of Jaycar said, “We recognise Campbelltown as a regional growth center 46  Silicon Chip and want to be part of that growth”. “With its major administrative and educational infrastructure, Campbelltown is a natural choice for our newest store and we are pleased to be here and part of the ongoing development of the Macarthur region” Jaycar’s new store is located in Shop 2, 49 Queen St (Cnr Langdon Ave.) in Campbelltown. Phone 4620-7155 Contact: Jaycar Electronics 100 Silverwater Rd, Silverwater NSW 2128 Phone: (02) 9741 8567 Fax (02) 9741 8588 Website: www.jaycar.com.au www.siliconchip.com.au See-in-the-dark video “Snooper” from DSE Elsewhere in this issue we feature the SOOPER SNOOPER. Well, here’s the video equivalent – the Apple Nightowl from Dick Smith Electronics. The Nightowl allows you to view up to 100 metres in absolute darkness, 150 metres in starlight or 200 metres in moonlight. You view the scene through the Nightowl’s video imager, which shows in a monotone green. Suggested uses (apart from snooping!) include security guards, nature lovers studying nocturnal wildlife (they don’t say what or how wild!) and even for boat owners trying to pick up that elusive mooring in the dark. The Nightowl has 7000x light amplification and 3.6x image magnification. It is powered by two AA batteries and weighs in at 585 grams. A soft carry case is included. The Applie Nightowl is available from all Dick Smith PowerHouse stores in NSW and Victoria for $598.00. It is also available via mail orders (1300 366 644) or through www.dse .com.au Contact: Dick Smith Electronics 2 Davidson St, Chullora NSW 2190 Phone: (02) 9642 9100 Fax (02) 9642 9153 Website: www.dse.com.au Honey, I shrunk the keyboard . . . If you’re a bit tight on space (or don't like a big keyboard taking up real estate!) Microgram have this nifty little PS-2 keyboard available. The keys and key spacing are full size, so you won’t have any excuse for poor typing, but everything else about this keyboard is tiny. It measures just 295 x 145mm and is about 35mm deep at the back. Naturally, they've had to sacrifice the numeric keypad (it piggy-backs on some of the alpha keys) but all other keys are there, if a little smaller than usual! You can check this little number out by calling Microgram or visiting their website. 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 High Efficiency, Low Noise White LED Driver The LT1932,is a switch-mode, fixed-frequency, constant-current boost regulator optimized to drive white light emitting diodes (LEDs). The fixed operating frequency of 1.2MHz allows the use of very low profile inductors and small ceramic capacitors, while minimizing emitted noise. Typical efficiencies over 80% are obtained compared to the 50%-70% efficiencies of charge-pump solutions. Contact: Microgram Computers Unit 1, 14 Bon Mace Close, Berkeley Vale NSW 2261 Phone: (02) 4389 8444 Fax 1800 625 777 Website: www.mgram.com.au Contact: REC Electronics Unit 1, 38 South St Rydalmere NSW 2116 Phone: (02) 9638 1888 Fax (02) 9638 1798 Website: www.rec.com.au PARALLAX BS2-IC BASIC STAMP $112.00 INC GST WE STOCK THE COMPLETE DEVELOPMENT SYSTEM www.siliconchip.com.au September 2001  47 BASIC Stamp development kit from RTN To say that the BASIC Stamp has enjoyed phenomenal success is akin to saying that computers are popular! As a means of “getting into” microcontrollers, there is probably none better. With their easy-to-learn (and even easier to understand) language there are literally hundreds of thousands of people who started out with the BASIC Stamp. This popularity has spawned a huge library of Stamp applications, with dozens of websites, user groups and newsgroups devoted to the subject. A great place to start is the manufacturer’s website, www.parallaxinc.com. Or try typing “Basic Stamp” into any search engine (Google is accessible from the SILICON CHIP website) and you’ll see what we mean (about 290,000 references, according to Google!) The BASIC Stamp development kit, available from RTN allows users to develop and debug their own BASIC Stamp designs. It features a BASIC Stamp BS2p 24 module, BASIC Stamp starter kit on floppy disk, BASIC Stamp manual (Version 2) and a selection of interconnecting cables. Further information on this and other BASIC Stamp products can be obtained from the RTN website. Contact: RTN 35 Woolart St Strathmore Vic 3041 Phone/Fax (03) 9338 3306 Website: www.nollet.com.au Denon’s 5-channel DVD Surround Receiver has Dolby Digital & DTS Denon’s newest model, the ADV700 surround receiver, is equipped with both Dolby Digital and DTS 5.1 channel decoding, along with a Dolbt Pro Logic II decoder which simulates 5.1 surround sound from a 2-channel (stereo) source, such as conventional CDs, discs and tapes. DVD discs can be in either NTSC or PAL format. You have the option of composite video or S-video output while DVDs also have RGB output as well. In audio mode, when you insert a disc, the ADV-700 automatically detects the sound format and plays it in the appropriate mode. It also does this with digital broadcast satellite (DBS) signals. In addition, the receiver also automatically detects CD-R and CD-RW discs recorded in MP3 format. Three sets of video terminals and four sets of audio terminals are provided to connect a video player, TV or other video and audio devices. The ADV-700 allows you to make system settings via your TV screen. It also includes FM and AM tuners covering 87.5-108MHz and 5221611kHz. Each of the power amplifiers is rated at 35W RMS (6 ohms, 1kHz, 10% THD). While many of the functions are controlled via the front panel, there is an extremely comprehensive infrared 48  Silicon Chip remote control unit for all functions. Denon models are handled by selected hifi and video retailers. For the location of your nearest retailer, contact the Australian distributors of Denon, Audio Producs Australia. Contact: Audio Products Australia Pty Ltd 67 O'Riordan St, Alexandria NSW 2015 Phone (02) 9669 3477 Fax (02) 9578 0140 Website: http://elec.denon.co.jp/europe/ First MiniDisc player to feature Dolby Headphone Sharp Corporation has launched the new MD-ST880 MD player featuring the Dolby Headphone technology developed by Australian company Lake Technology. Dolby Headphone delivers a spatialised stereo sound experience over any ordinary stereo headphones. The ST880 features MiniDisc Long Play, a new encoding method for audio on MiniDisc which effectively doubles the storage capacity. MPLP offers two long play modes: LP2 which will record 160 minutes in stereo and LP4 which uses greater compression to allow 320 minutes recording time in stereo. Sharp announced earlier this week the new DV-L90TC DVD Mo- bile Theatre with Dolby Headphone, while in the PC sector, Sharp feature Dolby Headphone in their recently announced PC-MJ760C, an A4-size all-in-one notebook PC, part of a four model range. Lake Technology also announced this week a commercial partnership with one of the leading music software companies, MUSICMATCH Inc, which will see an aggressive roll-out of the Lake-branded Dolby Headphone plug-in for MUSIC-MATCH Jukebox. Contact: Lake Technology Ltd Box 736 Broadway NSW 2007 Phone (02) 9213 9000 Fax (02) 9211 0790 Website: www.lake.com.au www.siliconchip.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.jaycar.com.au SERVICEMAN'S LOG From here, there and everywhere This month, I’m taking a break from my own workshop and presenting three servicing stories sent in by readers. They cover repairs to two colour TV sets and an elderly VCR with lots of problems. Let’s get straight into it. The first contribution comes from Mr R. H. of Carine, Western Australia and he’s called it “A Sad Repair Story.” I’ll let him tell it in his own words: It concerns a Sharp CX3451 colour TV set which an elderly relative had imposed on me to repair, after she could not get a response from two repair shops advertising in the local newspa­per. My main business involves the repair of switchmode power supplies and other industrial electronics equipment and general­ly I shy away from domestic appliance repairs. I find that, in most cases, the time spent is much greater than one can legiti­ mately charge a customer and even if you do charge a modest amount, you are still accused of overcharging. So to my story. The set was work- ing but could be induced to lose the picture, with the screen collapsing to a horizontal line, by tapping on the outside of the case. My thoughts were that it was obviously a loose connection or a faulty joint prob­lem and that it shouldn’t take too long to find. I discharged the tube before removing the EHT lead and it was a simple matter to remove the main board. I thoroughly inspected the board with a magnifying lamp but for the life of me, I could not detect a connection or soldered joint which I could honestly say would cause the symptom – and I have had many years experience in locating this type of fault. There have not been more than a few cases where I could not pick a faulty joint by visual inspection but the symptoms indicated that there was almost certainly one here. I decided to try the shotgun approach and resolder all the most likely suspects but as I later discovered, this only caused the real fault to temporarily disappear. Anyway, having completed the resol­dering, I put everything back together and could not get the set to falter when I gave the case a solid tap, so I took it back to my relative. No sooner had I fired it up than there was the same fault back again. I took it home and decided to get the board operating out of the case. However, the leads from the degaussing coil were too short to allow this, so I decided to remove the tube as well and connect everything up on the floor. I arranged the tube with some soft wedges to keep it upright and when all was ready I fired it up. I went around the suspect area of Items Covered This Month • • • www.siliconchip.com.au Sharp CX3451 TV set. Sharp VC-90ET VCR. Philips 14CF1014 portable TV set. September 2001  57 the board, tapping it gently with a plastic toothbrush handle, and found that I could induce the fault reliably with the gentlest of touches in a fairly small area. I thoroughly re-soldered every joint in a diameter of 75mm and this time, I was unable to induce the fault when the board was tapped. I had fixed the fault for sure but this was not the end of the story. During the time the whole box and dice was set up on the floor, I had forgotten to reconnect the lead which connects the aquadag of the tube to the 0V rail on the PC board and the tube was thus sitting several thousand volts above chassis. Unfor­tunately, due to the very short de­ guassing coil leads, the aqua­ dag finished up within a couple of millimetres of the metal casing housing the infrared receiver module. I remembered I had heard a spark jump while tapping the board and looking for the original fault but I had not actually seen it. Since it appeared 58  Silicon Chip to have had no effect on the picture or the manual operation of the set using the front panel controls, I concluded it was of no consequence. I didn’t have the remote control unit with me anyway so I couldn’t check it out. At this stage, I decided to put it all together and deliver it once again to my relative who was pleased as punch when I demonstrated that the original fault was now fixed. However, shortly after arriving home, I received a phone call from my relative to tell me that the remote control was not working. Uh-oh, I thought, maybe that spark was telling me something after all. I decided to leave it until the next day and work on it then. I suspected that the IR module was dead and hoped that that was all there was to it. I removed the module (a Sharp GP1U5 IR receiver), connected it to a 5V supply and connected a CRO to the output. Sure enough, the module was self-triggering in an erratic manner without any signal being received. I checked the Sharp parts supplier and he had a unit in stock at around $16. I thought this was rather high, so I decided to try the Tandy GP1U5 copy (276-0137) at $3.90. This Tandy unit was a vertical mount model but I was able to remove the internal PC board, change the connection pins and then remount it in the horizontal casing from the original unit. This unit worked perfectly when tested on the bench, the unit responding to the remote control with a no-load output signal of around 5V p-p. I then refitted the module to the main PC board, connected everything together and gave it a try. It did not respond to the remote control so out it came again. Next, I decided to just try the board without connecting the tube but in order to do this safely it was first necessary to remove the horizontal output transistor to prevent the EHT zap­ping anything. I connected the CRO to the output of the IR module and when the remote was operated, the signal amplitude was only around 400mV p-p. This was insufficient to drive anything in the 54-pin Sharp IX1703CEZZ IC. De-soldering pin 46 on this IC and checking with a diode tester showed that the internal protection zener on this input measured high leakage in the reverse direction, thus indicating it was indeed zapped. A new IC from Sharp was going to cost $43.50 (ouch!) and would take several days to obtain from Sydney. It seems that my small oversight in not connecting that chassis lead had acciden­tally led to both the IR module and the function control IC taking a direct hit and thus resulting in my good deed for my relative costing more than anticipated. Multi-standard VCR The next contribution comes from Mr A. B. of Glen Waverley, Victoria. He calls it “ The (more than) Multi-Standard VCR.” The machine in question was an elderly Sharp VC-90ET VCR, a topof-the-line, multi-standard unit that does everything. It has stereo hifi, will record/playback NTSC, SECAM & PAL (all at a bewildering variety of chroma frequencies), and features standard play and long play. All-in-all, a very fine machine. It was, alas, somewhat sick, hence www.siliconchip.com.au its arrival at my work­shop. The owner brought it in saying “you were recommended by my neighbour, you fixed up her 78 RPM gramophone.” This set me back somewhat; I know I’ve been fixing things for a while but I am not that ancient! Actually, it was an old Garrard turntable that I’d repaired, so that some vintage jazz 78s could be copied onto tape but that’s another story. The Sharp VCR was not well – the front panel display was very dim, the mechanism was making horrible grinding noises, it was chewing tapes and the audio was shocking. As well, there was some patterning on the received off-air picture. This latter problem was tackled first. This VCR, like most modern machines, has an RF output in the UHF band and this needed to be checked. To do this, the test switch on the back of the set was turned on and the workshop TV set put into search mode until the two white tuning bars were found. The test switch was then set to “Off” and the poor picture revealed. When the VCR operate switch was turned off, the monitor screen produced a faint Ch31 picture – ie, classic co-channel interference. By using a small screwdriver, I was able to adjust the RF output clear of the occupied channel and a good picture came up. Next, a dummy tape was inserted and the machine put through its paces. Fast forward and rewind (FF/REW) were horrible – the capstan motor obviously had dry bearings (a common problem) and a squirt of CRC 226 gave a temporary cure, pending a proper motor strip down and clean/lubricate. The PLAY mode was then selected and this started the head drum and moved the tape guides into position, as expected. I then pressed the EJECT button. The cassette ejected OK but the guides hadn’t retracted, which meant that the tape hadn’t unlaced. Little wonder it was chewing up tapes. This sequence was repeated a few times and there were variations – sometimes it would work perfectly, sometimes the head drum wouldn’t start and sometimes it displayed the original behaviour. This indicated an intermittent mode switch so it was removed and cleaned, which cured this fault. As well, during all these repairs, the relevant drive and loading belts were progressively replaced. www.siliconchip.com.au The sub-loading arm was also very stiff (this manifests itself as no – or erratic – tape counter) and so this was also sprayed with CRC 226. The final mechanical problem was poor rewind, especially the last few minutes of a tape (or the first few minutes if playing from the beginning of the tape). The cure for this is to disconnect power, remove the cas­ sette cradle, and manually rotate the loading motor until all arms, etc are clear of the take-up reel. This is then removed, the dust, etc cleaned out from underneath, the soft brake pads deglazed from the two brake arms and the rotation sensor cleaned. It sounds complicated but it’s easy after you’ve done it a few hundred times! As a final step, the worn (glazed) pinch roller was re­ placed and the heads (ie, audio/video/control/erase) cleaned. We now had a mechanically functioning VCR. The next step was to repair the front panel display. This problem was traced to multiple faulty and out of tolerance ca­pacitors in the power supply module – again, so far so good and I now had a nice bright readable display. The last (and most perplexing) fault involved a number of audio problems. The VCR was connected to the workshop stereo amplifier and speakers, and a stereo test tape run. This resulted in the classic “chuff chuff “ sound of an FM carrier dropping in and out. My first thought was worn audio heads – very rare on Sharp machines but not unknown. The pins from the head drum were desoldered and the Q of the heads measured – they were still excellent and more to the point, both heads were very close to the same reading. This ruled out worn/damaged heads. A further test at this stage is to select PLAY and listen – with the stereo heads physically disconnected, the machine should default to mono audio and any FM noise should disappear. As well, the front panel level meter should show a mono signal. This wasn’t happening; there was still heaps of noise and the level meters were showing stereo L and R – not possible! As well, it was now observed that there was FM white noise coming through with the mono signal on the monitor. I resoldered the heads in disgust and wandered off for a cup of tea and a good think! The Tiger comes to Australia The BASIC, Tiny and Economy Tigers are sold in Australia by JED, with W98/NT software and local single board systems. Tigers are modules running true compiled multitasking BASIC in a 16/32 bit core, with typically 512K bytes of FLASH (program and data) memory and 32/128/512 K bytes of RAM. The Tiny Tiger has four, 10 bit analog ins, lots of 2 digital I/O, two UARTs, SPI, I C, 1-wire, RTC and has low cost W98/NT compile, debug and download software. JED makes four Australian boards with up to 64 screw-terminal I/O, more UARTs & LCD/keyboard support. See JED's www site for data. TIG505 Single Board Computer The TIG505 is an Australian SBC using the TCN1/4 or TCN4/4 Tiger processor with 512K FLASH and 128/512K RAM. It has 50 I/O lines, 2 RS232/485 ports, SPI, RTC, LCD, 4 ADC, 4 (opt.) DAC, and DataFLASH memory expansion. Various Xilinx FPGAs can add 3x 32bit quad shaft encoder, X10 or counter/timer functions. See www site for data. $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 September 2001  59 The machine had been left running while the cup of tea was organised and, while idly sitting with the brain in neutral, I suddenly realised that there was modulation coming through the stereo speakers but that it wasn’t from the tape – it was from a local AM broadcast station! I traced out the audio lead from the head amplifier pack and noticed that just wrapping my fingers around the connector where it entered the audio processing board was enough to remove the interference. This was obviously not a longterm solution unless I was prepared to move in with the customers! The connecting lead was removed and the continuity of signal conductors and earth screening was checked – all OK. What now? – the thing looked like it was functioning as designed and the manufacturer had provided proper screening of the low level signal leads. And then I suddenly thought of the junk pile at the back of the workshop. I had scrapped a whole pile of monochrome IBM monitors a few years back and remembered they all had toroid formers on the signal input leads, obviously put there to suppress any noise from the computer radiating via the monitor leads. One of these 60  Silicon Chip was chopped off the IBM, and as luck would have it, there was a big enough hole to pass the connectors on the end of the Sharp audio lead. There was also enough cable to be able to wind two turns around the toroid. This was lashed into place with nylon cable ties and, much to my relief, the problem was cured! A follow-up phone call a few weeks later to the customer revealed all was well and they were recommending me to all and sundry .... an ideal way to finish a job! Faulty memory Contribution number three comes from Mr J. R. of Deer Park, Victoria. There may be a temptation to describe it as a memory fault – but it has nothing to do with computers. Anyway, this is his story. I’m a TV/video tech by trade but I’m now on a disability pension. I did a mature-age apprenticeship which took me through a few employers who fixed all kinds of gear, ranging from TV sets to video and audio equipment. My last job involved computer monitor repairs. These days, I fix electronic equipment for friends. I main­tain a small workshop in my 3m x 3m shed and carry a reasonable stock of passive and active spare parts, mainly for electronic projects from SILICON CHIP which I build for myself or mates. Recently, one of my mates landed me with a Philips portable TV set Model 14CF1014 (CF-1 chassis), explaining that it was his daughter’s set and that she had been complaining of funny co­lours. She uses this set mainly for her beloved Playstation. He also complained that, on some of the games she played, the pic­ture would roll. The second fault I already knew about (of which more later) and I didn’t think the second would be hard to fix, so I told him it should be ready in a day or two. He urged me to fix it ASAP as, in the meantime, she would want to use his main TV set for her game playing and he’d miss out on all his favourite shows. I promised him top priority. When I switched the set on, I found that all the colours were indeed wrong. I was watching soccer highlights and found that the grass was blue and the player’s faces were green. I then switched my workshop portable on to compare the colour differences and found that a billboard which should have been green was actually red. I’d seen this fault before many years ago in an old Prin­cess TV set and I attributed that fault to a faulty colour pro­cessor chip. Feeling that this would also be the problem here, I attacked this section first. First, I measured all the pins on the chrominance/luminance chip, which was a TDA3560 (designated as 7192). These all measured OK so I next checked transistor 7148 (BC548), the Y signal buffer, for correct voltages. These were also spot on and capacitors 2218 (2.2µF), 2191 (1µF) and 2192 (22µF) were all within tolerance. I next checked the 185V rail filter capacitor (3.3µF 250V) and found it to be down to only 1µF. Bingo! I replaced this with a sturdy 350V job, turned the set on and found I was back to square one; still the same mismatch. Damn – I thought I had it. I was now beginning to suspect the aforementioned TDA3560 chip. I didn’t have one in stock so I ordered one from my supplier. When the chip arrived the following day. I proceeded to fit it. But prior to that, I’d fitted an IC socket to make the job easy. Isn’t it strange www.siliconchip.com.au how quickly one likes to know whether you were right with your diagnosis or not? After a quick fit and a turn on, I stared at the screen in disbelief. I was still seeing mixed colours. So much for blaming the chip. Where to now? I plonked the set face down on the bench and began making some more voltage checks in the hope that I had missed something. As I was prodding, around the chroma chip, I decided to look at the picture by tilting the set up and bending down to look at the screen. To my surprise, all the colours were back to normal! What did I do to fix it? I well remember a computer monitor that had a no-power fault but fired up when I touched my multi­ meter probe on a resistor in the start-up circuit. But what could I have prodded to get this set to behave normally? The answer soon came. I switched the set off and stood it up into its correct position and fired it up. The mixed colours were back. Ah-ha! Now I’ve got you! With the set still on, I then turned it face down. The colours went back to normal. I now knew I had a purity problem, not a colour-processing fault as I originally had thought. I turned the set off, turned it back into its correct position, and went straight for the degaussing thermistor. When I pulled it out, I gave it a bit of a shake, and I could hear something rattling inside. I’d finally found the culprit. Luckily I had one in stock and fitted it. I switched on – the picture was still a bit poor but a whole lot better than before. I brought out my magic wand and degaussed the set and that was it – a perfect picture. I did a few geometry and white balance adjustments and the set came up like new. Now I had to tackle the vertical hold problem. I removed the vertical hold adjustment – a 1MΩ trimpot (3413) – and re­placed it with three wires to which I joined a large 1MΩ pot. Then I drilled a hole in the front panel (bottom right) and fitted the pot in there. They now have an external vertical hold control. A cheaper way of doing this is to adjust the original trim­pot to a centre frequency, between 50Hz and 60Hz. To do this, you need a chipped Play­ station and a PAL and NTSC game. You alter­nate, changing between the PAL and NTSC games, while slightly adjusting the trimmer until you get no picture roll on either formats. And that’s it – instant fix but I like to give friends an external control. My friend didn’t waste time picking up the set. His daughter had complained that the large 68cm TV set she had purloined for her Playstation were making all the characters look too big and she wanted her little set back. When I think back to my apprenticeship days, I remember being told to degauss a set with gross colour problems first before condemning the electronics. Looks like I need more experience . . . SC or a better memory. K&W HEATSINK EXTRUSION. SEE OUR WEBSITE FOR THE COMPLETE OFF THE SHELF RANGE. www.siliconchip.com.au September 2001  61 Personal Noise for Tinnitus This Personal Noise Source produces pink or white noise and can be used to drive headphones or an external speaker to block out unwanted noise. It has been specifically designed for Tinnitus sufferers but can be used by anyone who wants to mask unwanted sound. W low level broad band noise. TRT does frogs in a fishpond, right outside his hy would you want a Pernot cure Tinnitus but it does make bedroom window, who play “who sonal Noise Source? Isn’t it manageable for people who are can make the loudest mating calls” there already enough noise severely affected. all night (they’re silent during the day, in this world? of course!). Now frogs are a protected Well, believe us, if you suffer from Want more information on Tinnispecies and our bloke doesn’t want the Tinnitus, this Personal Noise Genertus? There is not much more to tell wrath of the Government Inspector of ator is virtually the only treatment although there are lots of websites Frogs coming down on him. Switch on available. It is cheap and you can do devoted to it. Just call up your favourthe PNS and – ahh, bliss: sleep at last! it yourself. ite search engine (Yahoo, Google etc), type in Tinnitus and you will find lots When we said the PNS blocks noise, If you have never suffered Tinnitus, of references. that’s not strictly true. It doesn’t really congratulations; you are fortunate. block it out: it more “masks” it by You don’t know what it’s like. Tinnitus OK, that’s enough about Tinnitus increasing the ambient level so that is the perception of sound when no for the moment. Even if you don’t the unwanted noise is much less obexternal sound is present. Commonly suffer from this affliction, there are trusive. The “noise” from the PNS is referred to as “ringing in the ears”, times when a low-level noise source something you can live with – in fact, Tinnitus may sound like humming, can be really helpful in blocking out it is often quite soothing. It has been clicking, buzzing, ringing, hissing, extraneous noise. likened to what you hear from roaring, whistling or crickets. One of For example, if you are trying to a soft waterfall or a stream the staff members of SILICON cascading down rocks. CHIP occasionally experiences it and he reports that The Personal Noise Source it sounds like a tone at about is built into a small plastic or loudspeaker case and as mentioned e on ph ad he 400Hz. Fortunately, in his r fo e bl ita ❍ Su case it rarely lasts for more above, can be connected to noise output than a few minutes. headphones or to a small ❍ Pink or white ed at er loudspeaker. It can be powTinnitus may be intermitop ck pa ❍ Battery or plug ered from a DC plugpack or tent or constant and may vary e control 9V battery. It includes a volin loudness depending on ❍ Inbuilt volum ume control and can prostress, medications and the vide pink or white noise. surrounding environment. What’s the difference? Most people who experisleep and a nearby neighbour is havence Tinnitus are not really “White” and “pink” noise ing a boisterous pool party: switch on bothered by it. But some people find this Personal Noise Source (PNS) and that it seriously disturbs their sleep White noise has equal energy per you can blank it all out. Or maybe you while others find it really debilitating. constant bandwidth. So the 1kHz are trying to study and someone else band from 1kHz to 2kHz will have the For those people who are seriously in the family persists in listening to a same energy level as the 1kHz band affected, Tinnitus Retraining TherMarilyn Manson CD; again, switch on from 10kHz to 11kHz. In practice, this apy (TRT) can provide an effective your PNS and blot it out of existence. means that white noise has a 3dB rise treatment. Developed by Dr Jawel Another of our staff members has in amplitude for every octave. Jastreboff, TRT involves the use of atures Personal Noise Source Fe 62  Silicon Chip www.siliconchip.com.au se Source SUfferers By JOHN CLARKE Pink noise has a flat frequency response or equal energy for each octave; the energy from 20Hz to 40Hz is the same as the energy from 10kHz to 20kHz. In effect, this means that pink noise sounds more subdued and less harsh than white noise. Putting it another way, pink noise has more bass and less treble than white noise. Pink noise is also used for measuring loudspeaker systems so even if you don’t need this PNS for blanking out unwanted noise it could be handy if you are involved in developing loudspeakers. Circuit description Fig.1 shows the circuit diagram. It comprises a white noise source (Q1), www.siliconchip.com.au amplifier (IC1a), pink (low pass) filter and further amplification (IC1b), followed by the volume control (VR1) and power amplifier (IC2). Transistor Q1 is the noise source. Its base-emitter junction is connected the “wrong way around” so that reverse current flows. Normally this could lead to breakdown of the transistor but the 180kΩ series resistor limits the breakdown current to about 30µA so no damage occurs. Connected this way, Q1 functions like a zener diode and produces a noise signal across the 180kΩ current limiting resistor. The supply to Q1 is decoupled with a 470Ω resistor and 1000µF capacitor and a 12V zener diode regulates the voltage so that the noise level is constant regardless of changes in the supply voltage. The noise signal is coupled to pin 3 of op amp IC1a via a 0.1µF capacitor. IC1a is set to provide a gain of 11 by virtue of the 100kΩ resistor between pins 1 and 2 and by the 10kΩ resistor in series with the 1µF capacitor. The 1µF capacitor rolls off frequencies below 16Hz while the 10pF capacitor across the 100kΩ feedback resistor rolls of frequencies above 160kHz. Pink noise filter The output of IC1a drives a fairly complex RC network which functions as the pink noise filter. It attenuates the September 2001  63 white noise at a rate of 3dB per octave. This filter is accurate to ±0.25dB from 10Hz to 40kHz, assuming close tolerance capacitors. Switch S2 enables the pink noise filtering to be disabled to let the white noise through without attenuation. Depending on how S2 is set, the pink or white noise is AC-coupled to pin 5 of op amp IC1b via a 0.1µF capacitor. When S2 is closed, the 220kΩ and 10kΩ feedback resistors for IC1b set the gain at 23. Low frequency rolloff is set at 16Hz with the 1µF capacitor. The 4.7pF capacitor across the 220kΩ resistor gives high frequency rolloff above 153kHz. But not only does switch S2 determine whether or not the pink noise filter is enabled, it also changes the gain of the following op amp stage involving IC1b. When S2 is open, the negative side of the 1µF capacitor associated with a 10kΩ resistor is disconnected from ground and is effectively connected to the pin 1 output of IC1a via the pink noise filter components. This means that the output signal from IC1a is fed to both the inverting and non-inverting inputs of IC1b. The gain for the non-inverting input is 23, as noted previously, while the gain for the inverting input is -22. Adding these two gains together gives a gain of 1. This means that the gain for the white noise signal is unity while the gain for pink noise is 23. This higher gain for pink noise compensates for the signal loss in the pink noise filter. Fig.2 shows the pink and white noise frequency response for the circuit. The output of IC1b is AC-coupled via a 10µF capacitor to the volume control potentiometer VR1 and then AC-coupled again to anLM386 power amplifier, IC2. Its gain is set to 200 by the 22µF capacitor between pins 1 and 8. The amplifier drives the external speaker or headphone load via a 470µF capacitor and a 4.7Ω resistor. There is also a Zobel network, comprising a .047µF capacitor and a 10Ω resistor, which is included to ensure high frequency stability. The speaker output is connected Fig.1 (left): the reverse-biased baseemitter junction of Q1 generates the noise in this circuit. It is amplified by IC1a and IC1b and the RC network following IC1a is the pink noise filter. 64  Silicon Chip www.siliconchip.com.au AUDIO PRECISION AMPLNOIS BANDPASS(dBr) vs BPBR(Hz) 20.000 06 MAY 100 04:02:31 15.000 10.000 5.0000 Fig.2: the pink noise output has a flat frequency response while the white noise shows a rising response with frequency. 0.0 -5.000 -10.00 -15.00 -20.00 T TTT 20 TT 100 1k via a 6.5mm stereo jack so that it can drive stereo headphones (with both channels commoned to provide mono mode) or a mono amplifier. The 4.7Ω resistor is series with the jack socket is included to prevent damage to the LM386 which could otherwise occur if a mono jack is inserted into the stereo output socket. Power for the circuit is derived from a DC plugpack or 9V battery. Reverse polarity protection is provided using diode D1 which prevents reverse current into IC1 and IC2. However, the supply for Q1 is taken before the diode to allow the maximum voltage from the battery. This is important since Q1 breaks down at around 7V or so. Once the battery drops below 7V, Q1 will be no longer produce any noise and the battery will need to be replaced. Reverse polarity protection is not strictly necessary for Q1 since it would be biased in the forward direction and the zener diode, ZD1 will conduct in the reverse direction and prevent the 10k 20k voltage exceeding 0.6V. The half-supply voltage for the op amps in IC1 is set using two series connected 10kΩ resistors across the Q1 supply and is decoupled with a 100µF capacitor. The power LED is driven via a 2.2kΩ resistor while the whole supply is decoupled using a 470µF capacitor. The DC socket connects the negative terminal of the 9V battery to ground of the circuit via an internal switch contact. The contact is opened if a DC plug is inserted, thus isolating the battery from the 12V plugpack supply. Construction All the parts of the Personal Noise Source are assembled onto a PC board measuring 60 x 70mm and coded 01109011. This is housed in a plastic case measuring 130 x 68 x 41mm. Fig.3 shows the PC board overlay and all the ex- ternal wiring. Begin construction by checking the PC board for shorts between tracks or any breaks in the copper tracks. The corners of the PC board should be cut out so as to clear the pillars within the box. You can begin assembly by inserting the PC stakes followed by the links and resistors. The resistor colour codes are shown in Table 1. It is a good idea to use a digital multimeter to check each resistor value as you install it. Next, insert and solder in the diode and zener diode, making sure that they are oriented correctly. Then insert and solder IC1 and IC2. Table 2 shows the codes you may need when installing the capacitors. The electrolytic types must be oriented correctly with the positive side placed as shown on the overlay diagram. Note that one of the 1µF electrolytics is positioned on its side as shown in the photograph. This is to allow the 9V battery to fit over this area of the PC board. Transistor Q1 is inserted next, along with the DC socket, the 6.35mm jack socket and pot VR1. The pot can be mounted onto the PC stakes on the PC board if it is a long shaft type. Scrape the coating off the pot body where it will be soldered to the two ground PC stakes. If you are using a pot with a short fluted shaft, mount it directly on the box lid and make the connections to the PC board with hookup wire. LED 1 needs to be mounted with its top 29mm above the PC board. Drill holes in the end of the case for the DC power socket and 6.35mm jack Fig.3: a stereo output jack is used to allow connection of stereo headphones. If you are using a speaker, you will need to connect it with a stereo jack plug. Do not use a mono jack otherwise it will short the output. www.siliconchip.com.au September 2001  65 Parts list – Personal Noise Source 1 PC board coded 01109011, 60 x 70mm 1 plastic box, 130 x 68 x 41mm 1 front panel label, 125 x 63mm 2 SPST mini rocker switches (S1,S2; Altronics S-3202) 1 PC-mount DC panel socket with 2.5mm pin 1 10kΩ log pot (VR1) 1 PC-mount 6.35mm stereo jack socket 1 stereo 6.35mm jack plug 1 9V battery clip holder (Altronics S-5050) 1 9V battery snap 1 knob to suit VR1 11 PC stakes 1 M3 x 6mm screw and nut 1 50mm length of 0.8mm tinned copper wire 1 100mm length of light gauge figure-8 wire Semiconductors 1 TL072 dual op amp (IC1) 1 LM386N-1 amplifier (IC2) 1 BC548 NPN transistor (Q1) 1 12V 1W zener diode (ZD1) 1 1N4004 1A diode (D1) 1 5mm red LED (LED1) Capacitors 1 1000µF 16VW PC electrolytic 2 470µF 16VW PC electrolytic 1 100µF 16VW PC electrolytic 1 47µF 16VW PC electrolytic 2 10µF 16VW PC electrolytic 3 1µF 16VW PC electrolytic 1 0.27µF MKT polyester 4 0.1µF MKT polyester 3 .047µF MKT polyester 1 .033µF MKT polyester 1 10pF ceramic 1 4.7pF ceramic Resistors (0.25W, 1%) 2 1MΩ 1 220kΩ 1 180kΩ 1 100kΩ 4 10kΩ 1 6.8kΩ 1 3kΩ 1 2.2kΩ 1 1kΩ 1 470Ω 1 300Ω 1 10Ω 1 4.7Ω Table 2: CAPACITOR CODES       Value 0.27uF    0.1uF    10pF    4.7pF IEC code 270n 100n 10p 4p7 66  Silicon Chip EIA code 274 104 10 4.7 This “opened-out” photo of the project shows the PC board and its connections to the switches on the front panel. The pot, DC and output sockets are all PC board mounting. Inset is the 9V battery holder – note the nut soldered in place. Table 1: RESISTOR COLOUR CODES    No.  2  1  1  1  4  1  1  1  1  1  1  1  1 Value 1MΩ 220kΩ 180kΩ 100kΩ 10kΩ 6.8kΩ 3kΩ 2.2kΩ 1kΩ 470Ω 300Ω 10Ω 4.7Ω 4-Band Code (1%) brown black green brown red red yellow brown brown grey yellow brown brown black yellow brown brown black orange brown blue grey red brown orange black red brown red red red brown brown black red brown yellow violet brown brown orange black brown brown brown black black brown yellow violet gold brown 5-Band Code (1%) brown black black yellow brown red red black orange brown brown grey black orange brown brown black black orange brown brown black black red brown blue grey black brown brown orange black black brown brown red red black brown brown brown black black brown brown yellow violet black black brown orange black black black brown brown black black gold brown yellow violet black silver brown www.siliconchip.com.au socket and on the side for the battery clip screw. One of the integral PC board slots will need to be removed to allow the battery clip to sit flush with the inside of the box. Use the front panel artwork as a guide to drilling the holes for the switches, LED and pot shaft. The cutouts for the switches are drilled and then filed to shape. Attach the front panel label and cut out the holes in this with a sharp utility knife. The PC board is inserted into the case with the ZD1 end going in first. The jack socket is then slid along to protrude through the end hole and is secured with its nut. Washers will be required on the jack socket inside the case. Attach the switches to the case lid and wire them as per the wiring diagram of Fig.3. Solder the battery clip leads in place and attach the battery clip holder. We found that it is easier to first solder the nut to the inside of this clip before attempting to mount it with a screw. Here’s how the whole lot goes together. The PC board snaps into place on the side guides – there are no screws to hold it in. Testing You can apply power to the circuit using a 12V DC plugpack, power supply set at 12V or with a 9V battery. LED 1 should light when powered. Check that the voltage at pins 1, 3, 5 & 7 of IC1 is at half-supply. The base- emitter voltage for Q1 should be around 7V. If it is equal to the supply voltage, check that the transistor is soldered in correctly. Note that some transistors break down above 7V and you may need to select a BC548 which has the lowest voltage across it if the PNS is to be battery-powered. The voltage at pins 3 & 5 of IC2 should be at nominal half-supply. Connect a set of headphones or loudspeaker via the jack socket and check that there is noise available both for the white and pink settings of S2. Current consumption at normal listening levels is around 25mA when driving a 4Ω speaker. This drops below 15mA with higher impedance headphones attached to the socket. This is OK for battery use but if you want to use it for long periods with an external speaker, a DC plugpack is the only practical approach. Remember that the loudspeaker must be connected via a stereo jack. If you use a mono jack, the output will SC be shorted. www.siliconchip.com.au Fig.4: actual size artwork for the PC board. Fig.5: actual size artwork for the front panel. September 2001  67 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. Switchable output crystal oscillator This oscillator circuit permits crystals to be electroni­cally switch­ed by logic commands. The circuit is best understood by initially ignoring all crystals. Furthermore, assume that all diodes are shorts and their associated 1kΩ resistors open. The two 1kΩ resistors at the non-inverting input of IC1 (LT1016) set the output to half the supply, ie, +2.5V. The RC network from the output to pin 3 sets up phase-shifted feedback and the circuit looks like a wide-band unity gain follower at DC. When crystal X1 is inserted (remember, D1 is temporarily shorted) positive feedback occurs and oscillation commences at the crystal’s resonant frequency. If D1 and its 1kΩ resistor are then REG1 LM317T IN 9V BATTERY OUT ADJ considered to be part of the circuit, oscillation can only continue if logic input A is biased high. Similarly, the circuit can only operate at crystal X2’s frequency if logic input B is high. Additional crystal/ diode/1kΩ resistor branches permit logic selection of the crystal frequency. For AT cut crystals about a millisecond is required for the circuit output to stabilise due to the high Q factors involved. Crystal frequencies can be as high as 16MHz before propagation delays in the comparator 13 330 RESISTANCE UNDER TEST + MULTIMETER The circuit of the Low Ohms Adapter gives good results for such a simple circuit. prevent reliable operation. Linear Technology application note. Low Ohms Adaptor for DMMs based on an LM317 regulator This adaptor circuit is essentially a 100mA constant cur­rent source. It is applied across a low-value resistor of unknown value (ie, the resistance to be measured) and the resulting voltage drop can then be measured by a digital UM66 SERIES TO-92 SOUND GENERATOR. THESE LOW COST IC’S ARE USED IN MANY TOYS, DOORBELLS AND NOVELTY APPLICATIONS 1-9 $1.10 10-24 $0.99 25+ $0.88 EACH INC GST 68  Silicon Chip www.siliconchip.com.au $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ As you can see, we pay good money for $ $ $ each of the “Circuit Notebook” contributions $ $ $ $ $ published. But now $ $ there’s an even better $ $ $ $ reason to send in $ $ your circuit idea: $ $ $ $ each month, the $ $ $ $ best contribution $ $ published will $ $ $ $ win winone oneof of $ $ $ $ these superb $ $ Wavetek Meterman $ $ $ 85XT true RMS $ $ $ multimeters - valued $ $ $ $ at around $380! $ $ $ $ So don’t keep that $ $ brilliant circuit secret $ $ $ $ any more: send it to $ $ SILICON CHIP and $ $ $ $ you could be a winner! $ $ $ Contributions must be your own original work or a major $ $ adaptation and not published elsewhere nor submitted for $ $ $ publication elsewhere. SILICON CHIP’s decision is final. $ $ $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ CONTRIBUTE AND WIN! 1 meter to win every month! multimeter (DMM). Setting your DMM to the 200mV range will enable it to measure up to 2Ω with high resolution while the 2V range will give a maximum resistance measurement of 20Ω. Construction could consist of mounting the LM317 adjustable 3-terminal regulator inside a small plastic box together with the battery and two resistors connected to the output and Adj pins. No on/off switch is required since no current will be drawn when no external resistance is connected across the Test terminals. Accuracy using 1% resistors should be within 5% and this could be improved by measuring the current, adjusting the resist­ance between the output and Adj pins of the LM317 to provide a precise 100mA. Before using the adaptor, check that your meter is not likely to be damaged by having the full output (6V+) applied when it is set to a low voltage range. Similarly, be aware that the voltage and current output of the adaptor may damage components if you use it for “in-circuit” tests. Peter Chamberlain, Strathfield South, NSW. ($30) www.siliconchip.com.au LED number display uses parallel port DIGIT 1 +5V TO PC PARALLEL PORT 2 DB0 7 3 DB1 1 4 DB2 2 5 DB3 6 16 5 4 A 3 B C D TO NEXT 4511 A VDD B C D LE IC2 4511 BI LT a 13 8 7x 220 a 12 b 11 c 10 d 9 e 15 f g 14 b c f b g d e e f g VSS DP 8 18-25 a c d COM +5V +5V 16 6 6 DB4 1 7 DB5 2 8 DB6 1 STROBE E VCC Y0 Y1 A0 Y2 15 14 13 DIGIT 2 12 DIGIT 3 IC1 Y3 74HC138 11 Y4 A2 10 4 Y5 E1 9 5 Y6 E2 7 Y7 GND 8 3 A1 DIGIT 4 TO 4511 LT PIN This circuit was developed as part of an MP3 player based Philip Chugg is this month’s winner on an old computer. The 2-digit display indicates which of the Wavetek song is playing. The LED display has the advantage that Meterman 85XT it is readable from a distance compared to a 2-line LCD. true RMS digita l The circuit could be used for other applications such as a multimeter. programmable calculator, stop-watch clock or scoreboard. The circuit uses a 74HC138 one-of-eight decoder connected to three data lines from the parallel port and a 4511 BCD to 7-segment decoder driver for each LED digit. The software was written using Q basic but should be easily converted to other languages. This example will output a 4-digit (or less) number to the parallel port to be displayed on a 4-digit LED display: CONST PPort = &H378 Number = 1234 n1$ = STR$(Number) n2$ = RIGHT$(n1$, LEN(n1$) - 1) FOR a = 4 TO 1 STEP -1 IF a > LEN(n2$) THEN lo = 15 ELSE n$ = MID$(n2$, LEN(n2$) - a + 1, 1) lo = VAL(n$) END IF hi = a * 16 OUT PPort, hi + lo OUT PPort, lo OUT PPort + 2, 1 NEXT Philip Chugg, Rocherlea, Tas. 'default address of parallel port (1) 'number to display 'convert number to string 'remove leading blank space 'this example uses 4 digit display 'is this digit used? 'not used, blank it out (can be 0) 'digit to be displayed normally 'get 1 digit only ‘convert to byte 'select digit to be displayed 'write value lo to digit hi 'select digit 0 (unused) fix timing error 'lock display 'get next September 2001  69 Hear Hear here! here! It’s It’s The The Sooper Snooper . . . With catlike tread, Upon our prey we steal; In silence drea d, Our cautious w ay we feel. No sound at al l! We never spea k a word; A fly’s foot-fal l Would be distin ctly heard . . . (from The Pira tes of Penzance ) Ever wanted to listen in to a quiet conversation on the other side of the street? You can with the Sooper Snooper! Ever wanted to listen in to bird calls without disturbing the birds? You can with the Sooper Snooper! Ever wanted to listen in to termites munching their way through your home? You can with the Sooper Snooper! Article by Ross Tester I f all this sounds a bit hard to believe, we have to admit that we were a bit skeptical too. That is, until we tried out this amazing device. Or more correctly, two devices. That’s because there are two versions of the Sooper Snooper, depending on what you want to do with it/them. 70  Silicon Chip One form, the type pictured above, has a small parabolic reflector with a microphone mounted “near enough” to its focal point. This particular Sooper Snooper is the one you would use to listen in to distant conversations, bird calls, etc – anything in the open air which would normally be too far away or too faint to hear. The second type of Sooper Snooper is pictured above right. It has a microphone physically connected to a “probe” which is touched against the object you want to listen to – such things as bearings inside a www.siliconchip.com.au Here’s the direct connection Snooper. Both it and the Parabolic model use almost identical electronics – the main difference is the microphones and their mounting. hard disk drive (see, boss, I told you my hard disk was getting old!), vehicle engine noises (it’s an old-time mechanic’s trick to hold a screwdriver on an engine block with the other end pushed against the ear – this one works on the same principle), you can even hear the water rushing through pipes – and much, much more. And yes, you really can hear termites attacking your home and cheque book if you’re unlucky enough to have an infestation! Don’t know which one would be more useful to you? Both have near-identical electronics, so you could build one and make the microphone “sensor” detachable so you could plug the other type in as required. That would be handy! Best of all, the project is easy to build, low in cost and has a lot of “wow” factor. You’ll amaze your family and friends – perhaps they’ll be a little more careful when they’re talking about you in future!!! Oh yes, there’s another feature we forgot to mention. This project can also act as an RF “sniffer” capable of detecting close-by transmitting “bugs” or other radio frequency sources in the vicinity. www.siliconchip.com.au You could even use it to listen in to a neighbour’s CB or amateur radio transmissions (of course, it won’t get the other side of the conversation). If you attach it to an outside aerial, you’ll probably find every local radio station coming in at once! So the Sooper Snooper is one versatile little project. The electronics The circuit is relatively straightforward, with an electret or dynamic microphone preamplifier (Q1) feeding into a “volume” pot (which, if you like, acts as a sensitivity control). The output from the pot drives an LM386 amplifier IC which is capable of driving a speaker or pair of headphones. You will note that there is a pair of Schottky diodes across the output for the headphones – these act as an automatic volume limiter to stop your eardrums melting if someone yells into the microphone when you’re least expecting it (Schottky diodes are used because of their speed and low forward voltage). The unit is powered by a 9V battery (although it can handle up to 15V) and has a regulated supply for the transistor preamp via the 5.6V zener diode. Looking back to the input for a moment, there is an RF pickup (ie an antenna) which drives a voltage-doubling rectifier/detector – the output of which can be directed to the preamp via a link. If you never plan to use the circuit as an RF sniffer, L1 and L2, D1 and D2, C1 and C2 and R12 could all be left out as they would have no function. Two types of microphones can be used in this project. In the parabolic model, a tiny electret insert is used to avoid “aperture blocking” of the dish. As you would no doubt know, electret microphones require a power source and in this circuit, power is derived from the 5.6V supply rail via a voltage divider and smoothing capacitor. For the direct-pickup model, a dynamic microphone insert is used. As these require no power source, the feed resistor (4.7kΩ) is left out. In this case, the adjacent 1µF capacitor must be reversed in polarity. The associated 1.5kΩ and 100µF capacitor have no function in this case and could be left out but its probably just as easy to leave them in, just in case September 2001  71 This circuit could also be used as a general purpose microphone preamp withVR1 made a external volume control rather than a preset pot. The two diodes across the headphone output are necessary to counter big variations in input level. you want to use an electret mic later. In the kit from Oatley Electronics, both types of microphone are supplied. The dynamic mic is a high quality Shure insert. The 4.7kΩ resistor is also left out if you wish to use the circuit as an RF sniffer. Construction There are two parts to the construction – the electronics, which as we mentioned is basically common to both types of project, and the microphone pickups. We’ll start with the electronics first. With the obvious exception of the microphone and headphones, all components are mounted on a single PC board measuring 50 x 45 mm. The dimensions of the board are actually quite critical because it must fit a particular 39k B .0033F D2 470pF + _ 72  Silicon Chip IC1 LM386 -OR+ HEAD_ PHONES D4 D3 22 + VR1 50k 4.7 100F + 1k 220 10k 100H 2700H 10k D1 Here’s another idea: if you think you might like to build both versions, + _ SPEAKER 1 Q1 + RF PICKUP INPUT Switch & socket option 1F C _ MIC ZD1 680 22 1.5k 4.7k 3.9k 100F + A + SHIELDED CABLE trolytic capacitors, transistors and ICs – are placed the right way around. The trimpot can be soldered in last. Now we turn our attention back to the 4.7kΩ resistor and the link: these depend on which version you are going to build. If you want to build the parabolic Snooper with the electret mic, put the 4.7kΩ in. If you want to build the probe Snooper with the dynamic mic, leave the 4.7kΩ out. The link is soldered between points A and B for either “audio” Snooper or between points A and C for the “RF” Snooper. Finally, give the board a good checking over to make sure everything is right and in the right place. 100F 100F + + 100F + TO 9V + _ BATTERY way into a small jiffy box, measuring 83 x 55 x 30 mm. The board is not held in by screws; rather it sits upside-down on the ridges in the case, leaving enough room for the on/off switch underneath and the 9V battery alongside (the photos give an idea of the arrangement). Screwing the case lid on holds everything captive. Start by assembling the PC board but first inspect it for any defects – bridges between or breaks in tracks, undrilled holes, etc. Then solder in the components, starting with the resistors (with the exception of the 4.7kΩ), then the capacitors, diodes, transistor and finally the IC. If you need to, check the resistors with a digital multimeter and/or refer to the colour code table – just to make sure! And as always, make sure that polarized components – diodes, elec- 1F .015F The PC board component overlay and the same-size photograph can be used as a quick reference guide during assembly. The link A-B should be changed to A-C for RF pickup. www.siliconchip.com.au why not put a suitable socket on the case with matching plugs on the two microphone types (a 3.5mm phono plug and socket would appear perfect). Then, mount a second switch inside the case connected between the 4.7kΩ and point A. Switch the resistor “in” when you want to use the parabolic Snooper and “out” when you want to use the probe Snooper. The headphones The headphones are standard hifi (ie, low impedance) types. If you’re using the Clarion ones from Oatley Electronics (as photographed with the kit), they attach to the PC board with the colour coding shown. Note that the wires in the cable are very fine and they also need to have a tiny amount of insulation stripped from their ends. Incidentally, these headphones are a real bargain at seventeen bucks a pair. They are very comfy and have an inbuilt level control (on the lead). Actually, this level control is the reason they’re so cheap: it has a tiny manufacturing defect which you can very easily fix in about thirty seconds with a screwdriver and a pair of pliers – a sheet which comes with the ’phones tells you how. Once you’ve made the fix, you may decide they’re too good for this kit and use them for your hifi system! Of course, any other low impedance ’phones or earpieces should work perfectly if you happen to have some on hand. The colour coding of the cabling might be different, of course – you will have to determine which is which yourself. Then again, it doesn’t really matter if you get the left and right channels mixed up – this is a mono output! The microphone(s) As we mentioned before there are two types of microphones usable in this project, depending on whether you want to build the parabolic (ie, long range) model or the direct pickup model. The Parabola Before we describe how we made the parabolic Snooper, a word of warning. The parabolic dishes from Oatley are disposals types which were intended for a small solar cooker. They do this by concentrating the sun’s rays at the focal point – and it’s easily hot enough to set fire to paper/boil www.siliconchip.com.au The parabolic version electronics “folded out” of their mounting box. The two large screws in the bottom of the box hold the handle onto the box. water/cook food/damage your eyes/ insert (ie, the “works” from a microcook you! phone) mounted somewhere near the parabola’s focal point. If you take the parabolic dish outside without having painted it When we say “somewhere near” a matte grey (as shown in our pho- we mean it: you don’t have to be all tos) BE CAREFUL. While your head will block most of the sun’s rays, there could still be enough to do you serious mischief! So before you do anything, spray the aluminium para-bolic dish with matte grey paint. OK, back to the Snooper electronics. Sound reflected back from the And this is what the box looks like complete. The PC parabola is picked board is held in place on the integral mounting lugs on up by a tiny electhe side walls of the box. There’s just enough room for tret microphone the 9V battery. It’s tight, but it all fits! September 2001  73 that accurate for the unit to work very well indeed. Of course, theory suggests it will work best when the mic is mounted right at the focal point. In prac- tice, we found out that you can be even a few centimetres away with little or no apparent degradation of performance. We mounted the microphone insert on a 150mm length of that highly specialized construction material we often use called “cotanger wire”. This won’t be supplied in the kit but if you have any difficulty finding a piece, just look in your wardrobe… We bent the wire into a “J” shape with the mic insert mounted at the bottom end of the “J”. It’s not actually secured to the wire; rather, some heatshrink tubing holds it (and its fine shielded cable) onto the wire. See the photo and you’ll see the arrangement. (Heatshrink tubing is not supplied in the Oatley kit). Note that the electret mic is polarised: it must be wired as shown or it won’t reward you with any sound! At the top of the “J” we bent the wire over 90° with a pair of pliers then fashioned a little loop in it. The screw which holds the reflector to its handle also passes through this loop to hold the J-wire in position. Again, see the photographs. The microphone on its J-wire can be moved around to find the best operating position but, as we mentioned, there is plenty of latitude for error. In fact, if you look at our photographs you may note that our mic is anything but on-axis. But it works very well! We drilled a just-large-enough (about 2mm) hole through the parabola for the shielded microphone cable to pass. This then was secured to the handle and went from there into the electronics box. If we were feeling real adventurous we might have drilled a small hole right through the length of the handle so that the cable was completely hidden. But we weren’t! (And also we didn’t have any really long drills available). Before moving onto the second type of Snooper, we should briefly describe that handle. It is simply a 35 x 18mm (dressed) The painted parabolic dish is secured to the handle by a single long bolt & nut, which also holds the microphone mounting wire in place. This is shown in close-up in the photo at right. The case (dotted) attaches to the bottom of the handle as shown in other photographs. 74  Silicon Chip www.siliconchip.com.au Parts List – Sooper Snooper 1 9V battery 1 9V battery snap 1 SPST mini rocker switch 1 PC board, 30 x 55mm 1 case, 83 x 55 x 30mm (Altronics H-0105 or similar) 1 pair hifi headphones Looking at the Parabolic Sooper Snooper from the rear, showing how the dish is connected to the handle; the handle’s connected to the case; the kneebone’s connected to de thighbone . . . Parabolic pickup: 1 electret microphone insert 1 Parabolic reflector, painted matte colour (grey) 1 60cm length stiff wire (eg, coathanger) 1 60mm M3 nut and bolt 2 M3 washers 1 wooden handle, approx 170mm long x 30mm wide x 18mm thick – see diagrams and text 1 20mm length 12mm heatshrink tubing 1 60mm length 3mm heatshrink tubing 1 100mm length shielded cable (for microphone) Scraps of thin hookup wire (for switch connection, etc) Direct pickup: 1 dynamic microphone insert 1 steel rod, 2mm diameter, with hard plastic handle, length around 220mm 1 2m length of shielded cable (for microphone) Araldite or similar glue. Semiconductors 1 LM386 audio amplifier (IC1) 1 BC549 NPN transistor (Q1) 2 1N60 germanium diodes (D1, D2) 2 1N5817 Schottky diodes (D3, D4) 1 5.6V Zener diode (ZD1) Capacitors 5 100µF 25VW PC mounting electrolytic 2 1µF 25VW PC mounting electrolytic 1 .015µF polyester or ceramic 1 .0033µF polyester or ceramic 1 470pF ceramic The same photo taken straight-on: between the two pics you should get a pretty good idea of how it goes together! Resistors (0.25W, 1%) 1 39kΩ 2 10kΩ 1 4.7kΩ 1 3.9kΩ 1 1.5kΩ 1 1kΩ 1 680Ω 1 220Ω 2 22Ω 1 4.7Ω 1 50kΩ preset pot, PC mounting Resistor Colour Codes           No. 1 2 1 1 1 1 1 1 2 1 www.siliconchip.com.au Value 39kΩ 10kΩ 4.7kΩ 3.9kΩ 1.5kΩ 1kΩ 680Ω 220Ω 22Ω 4.7Ω 4-Band Code (1%) orange white orange brown brown black orange brown yellow purple red brown orange white red brown brown green red brown brown black red brown blue grey brown brown red red brown brown red red black brown yellow purple gold brown 5-Band Code (1%) orange white black red brown brown black black red brown yellow purble black brown brown orange white black brown brown brown green black brown brown brown black black brown brown blue grey black black brown red red black black brown red red black gold brown yellow purple black silver brown September 2001  75 Capacitor Codes    Value IEC Code EIA Code .015µF 153  15n .0033µF  331  3n3 470pF  470 470p The completed “probe” which is actually a dynamic microphone insert Araldited to a long-bladed screwdriver. a hard glue ensures maximum sound transfer. We also filed off the screwdriver head to leave a flat “pickup”. This is perhaps unnecessary but it also stops anyone trying to use this as a screwdriver! Once the Araldite dried, we simply soldered the shielded mic lead to the appropriate points on the mic insert – and that basically finishes the second type of Snooper. Remember, though, that as this is a dynamic microphone that resistor we talked about before (4.7kΩ) should be left out. Here’s the back end of the probe showing how the screwdriver handle was ground flat then glued to the mic insert . . . . . . and from the opposite side, with the connections to the shielded cable which goes off to the preamp. In use softwood, about 175mm long, cut as shown in our drawing. Both ends are cut at an angle; one end has a further cut to allow mounting of the parabola via a single long bolt and nut passing through an appropriately drilledhole. Both handle and parabola were given a coat of grey spray paint before final assembly. transfer vibrations to the microphone without too much attenuation. Our pick-up is actually a long, thin-bladed screwdriver with a hard plastic handle. That part is important – a soft plastic would not transmit the sound vibrations as well as a hard plastic. The handle helps to stop the fingers absorbing or attenuating the sound vibrations picked up by the steel blade. We filed the back of the handle truly flat, then simply glued the microphone insert to that flat with Araldite. Again, Direct pick-up model This is considerably simpler than the previous type. All that is required is some form of pick-up which will Where d’ya geddit? This kit was designed by Oatley Electronics who hold the copyright on the design and the PC board. Oatley Electronics have available the following kits and options: Electronics kit: contains the PC board, all on-board components,     battery snap and both electret and Shure dynamic mic inserts........................$22.00 Box kit: contains the jiffy box and on/off switch................................................$5.00 Parabola: mill finish aluminium parabolic dish................................................$25.00 Headphones: high quality Clarion PRO-97V stereo headphones (note – small manufacturing defect in volume control, easily fixed, repair instructions included)............................................................................$17.00 Screwdriver: long screwdriver with solid plastic handle....................................$1.00 Not supplied: 9V battery, cotanger wire, heatshrink, wood handle Contact: Oatley Electronics, PO Box 89, Oatley NSW 2223 Phone (02) 9584 3563, Fax (02) 9584 3561 email sales<at>oatleyelectronics.com www.oatleyelectronics.com 76  Silicon Chip If your soldering is up to scratch, you should be able to put the headphones on your head, turn the unit on – and listen. You might have to adjust VR1, the “volume” control (which in this case acts more like a sensitivity control) to get the level you want. But that’s just about it. If it doesn’t work, once again check your soldering and component placement. Check that you have indeed included R4 if you made the electret version (conversely, you left it out for the dynamic version). Otherwise, measure a few voltages: the supply, of course and 5.6V across ZD1. Check that Q1 is operating by measuring the voltage between base and emitter – it should be about 0.6V. Finally, check that there is 9V between pins 6 and 4 of IC1. If all these are OK, perhaps it’s the ’phones that are giving you curry. Unsolder them and briefly connect a 1.5V AA cell across the leads when you’re not wearing them. A loud “click” means they’re probably working fine. Finally, with the ’phones back in place and VR1 set to maximum (ie, clockwise), do the “blurt” test: moisten your finger just a tad and apply it to the link connected to point “A”. If you get a “blurt” from the headphones, you know the amplifier is OK – all it can be is the connections to the microphone insert. Did you forget the link from point A SC to point B? www.siliconchip.com.au Using Linux To Share An Internet Connection; Pt.4 By default, Linux is a powerful operating system that automatically configures many services (eg, a web server) straight out of the box. In this final article in our gateway series, we show you how to improve security by shutting down any services that you don’t need and restricting access to those you do need. By GREG SWAIN You can’t be too careful about security when connected to the Internet, especially if you have a network behind your Linux box. Security must be built into the gateway from the beginning, otherwise you could end up being “cracked”. Don’t think that you’re safe just because you are using a dial-up connection. It’s quite possible for someone to find you and telnet their way into an unprotected machine in a matter of minutes. As well as having an effective firewall, there are a couple of other things you can do to improve security. This involves shutting down any services that you don’t need and restricting access to any that you do need. Turning off services The easiest way to deny access to a service is to turn it off. The first thing you need to do is take a look at the /etc/inetd.conf file (this is now /etc/xinetd.conf in later distributions such as Red Hat 7.0). This file lists all the Internet services started by the inetd Internet su- per-server daemon. You can disable any service listed in inetd.conf by placing a “#” (comment) at the start of the line. For example, to disable the ftp and telnet services, edit the lines to look like this: # ftp stream tcp nowait root /usr/sbin/tcpd in.ftpd -l -a # telnet stream tcp nowait root /usr/sbin/tcpd in.telnetd Note that this doesn’t stop you from ftping or telneting out from your machine. Instead, it stops your Linux box from behaving as an ftp and telnet server, so that these services are no longer potential pathways into your machines. The telnet service is a real risk – make sure that you don’t leave this running on an unprotected system. In fact, if you don’t need to run any Internet services, you can quite safely comment out everything in /etc/ inetd.conf. This will still allow you to access email and Tip 1: Logging Out & Logging In You don’t have to reboot Linux to log out as root and log back in as a user. All you have to do is quit Xwindows (click K -> Logout in KDE), type logout at the terminal prompt (or hit Ctrl-D) and then log back on using your user name and password. You can then restart KDE or Gnome by issuing the command startx. The procedure is identical for logging out as a user and logging back on as root. Fig.1 (left): you can turn off the services listed in /etc/inetd.conf by placing a “#” (ie, a comment) at the start of each line. Turn off all services that aren’t required. www.siliconchip.com.au September 2001  77 Fig.2: distributions that use xinetd.conf store a configuration file for each service in the /etc/xinetd.d folder. A service is disabled by opening its con­figuration file and changing the disable = no line to disable = yes. news, do all your usual web browsing and transfer ftp files. Once you’ve commented out the services you don’t need, you have to restart the inetd daemon with this command: killall -HUP inetd Recent Linux distributions that use /etc/xinetd.conf store one configuration file for each service in the /etc/xinetd.d folder. In that case, you disable a service by opening its con­figuration file and changing the disable = no line to disable = yes (Fig.2). You will need to do this for each service you want disabled. When you’ve finished editing these files, issue the command /sbin/serv­ice xinetd restart to pick up the changes. Note that many services will already be disabled by de­fault. Note too that not all network services are started through inetd or xinetd. Instead, some are started when the system boots. An easy way to disable (or re-enable) services is to use the ntsysv utility that’s included in both Red Hat Linux and Mandrake Linux. Issuing the command ntsysv brings up the tool as shown in Fig.3 below. You use the tab and arrow keys to move around, the spacebar to select or deselect a service and the F1 key to obtain a description of the selected service. Note that the ntsysv command on its own only configures your current run level. If you want to configure other run lev­els, then you need to include the level switch. For example, ntsysv --level 3456 lets you configure services for run levels 3, 4, 5 & 6. Don’t turn off all the services listed by the ntsysv utili­ty, as this could cause problems. Only turn off those network features that you don’t need. As a rule, you can turn off telnet, wu-ftp & tftp (both FTP servers), httpd (the Apache web server) and finger (this allows remote client to identify local users). If you don’t need any of the Internet super services started by inetd or xinetd, you can disable these as well. That simple step will stop all the services launched by inetd or xinetd in one swoop (after restarting, that is). Restricting access to services Any services that are left running in /etc/inetd.conf can be secured by “TCP wrappers”. For example, you might want to use your Linux box as a local web or email server. The idea here is to restrict access to services based on the host’s IP address. There are two files to edit here: /etc/hosts.deny and /etc/hosts.allow. First, open up the /etc/hosts.deny file and add the following rule to the end of the commented section: # /etc/hosts.deny ALL: ALL This tells the “TCP wrappers” to deny connections to all services from all hosts. It will also stop local machines on your network from accessing any wanted services, so we need to weaken the rules by adding some exceptions to /etc/hosts.allow. Open this file and add these lines: # /etc/hosts.allow ALL: 127.0.0.1 ALL: 192.168.0. This tells the “TCP wrappers” to allow connections to the services in /etc/inetd.conf from Fig.3: the ntsysv utility makes it easy to disable individual services. the local machine (127.0.0.1) and from the You can also disable multiple services by turning off inetd or xinetd. 78  Silicon Chip www.siliconchip.com.au Check These Websites For Firewall Tools & Linux Security Security really is a big subject and we’ve only covered the basics in this series. If you want to find out more, point your web browser to: http://www.linuxfirewall.org Included on this website are a number of firewall tools that you can use to create your own ipchain rules. In particular, take a look at PMFirewall and the Firewall Design Tool. These are both script files that ask you a series of questions and then create firewall rules based on your answers. Other tools worth looking at are Kfirewall 0.4.2 (which is a GUI front end for ipchains) and Gnome-Lokkit 0.43. Another good Linux security website is located at: http://www.linux-firewall-tools.com/linux Be sure to check the Firewall & LAN Security FAQ on this site. An excellent text on Linux security and other topics is Securing & Optimizing Linux: RedHat Edition. This publication includes an ipchains firewall and is available for free download from: www.linuxdoc.org/LDP/solrhe The Linux Network Administrators Guide, 2nd Edition is another excellent reference on security and firewalls (both ipchains and iptables). You can download it from: www.ibiblio.org/pub/Linux/docs/linux-doc-project/nag2 What about iptables? Recent distributions of Linux (eg, RedHat 7.0 and later) include a replacement for ipchains called iptables – although ipchains is still included and you can still run the ipchains firewall. The very latest releases, however, don’t have ipchains compiled into the kernel but generally include it as a loadable module. In that case, try adding the following lines at the very beginning of the rc.firewall script (we haven’t tested this, by the way): # Load ipchains module /sbin/modprobe ipchains Alternatively, you could use an iptables firewall script. The following two websites list iptables firewalls: www.spodzone.org.uk/packages/secure/iptables.sh www.amber.co.uk/iptablesrc The Linux Network Administrators Guide, 2nd Edition also includes an iptables firewall. Don’t Take Security For Granted For the home user, running the simple ipchains firewall from the June issue and turning off all external services makes for a fairly secure system. Just keep an eye on the log files for any untoward activity and you should be OK. That said, we don’t offer any guarantees – the net is not a safe place! If security is vital to your organisation, be sure to seek expert professional advice when it comes to setting up a firewall. Don’t just rely on the advice given in our articles. It’s also vital that you install the latest updates and security fixes, to prevent a hacker from taking advantage of a known security hole. You can get these from your distribution’s website (eg, www. redhat.com) or by visiting www.securityfocus.com Fig.4 (left): chkconfig --list lets you quickly check which services are running. Fig.5 (below): the netstat utility shows which services are listening for TCP packets. local network (192.168.0.). And yes, you must include the full stop at the end of the second line. Finding out what’s running? You can quickly find out what services are running using the command chkconfig --list. This begins by listing all the system services and their run levels, then lists the services managed by xinetd (see Fig.4). You can also use chkconfig to turn a service off. For exam­ple, chkconfig --level 345 xinetd off turns xinetd off at run levels 3, 4 and 5. You will have to reboot for the change to take effect. Another handy tool is the netstat utility. This is used to www.siliconchip.com.au show which services are listening for TCP packets. Typing netstat -ant, for example, gives a response as shown in Fig.5. In this case, ports 6000, 139, 515, 22, etc are listening and you can find out which services these correspond to by looking in /etc/services. Finally, you should check out the “Firewall And Proxy Server Howto”, along with these two documents: (1) “Controlling Access To Services” from www. polarhome.com/service/manual/RedHat/s1-sysadmin-access; and (2) “Securing Your Net Connection” from www. SC noether.freeserve.co.uk/secure September 2001  79 SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au SILICON CHIP If you are seeing a blank page here, it is more than likely that it contained advertising which is now out of date and the advertiser has requested that the page be removed to prevent misunderstandings. Please feel free to visit the advertiser’s website: www.altronics.com.au Order Form/Tax Invoice Silicon Chip Publications Pty Ltd ABN 49 003 205 490 PRICE GUIDE- Subscriptions YOUR DETAILS (all subscription prices INCLUDE P&P and GST) Your Name________________________________________________________ (PLEASE PRINT) Organisation (if applicable)___________________________________________ Please state month to start. 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Australia: $A7.70 ea (including p&p by return mail)     Overseas: $A10 ea (inc p&p by air). *BINDERS: BUY 5 or more and get them postage free.   (Available in Aust. only.) ..........................$A12.95 ea (+$5.50p&p). *SOFTWARE: $7.70 per item (project) plus $3.30 p&p per order within Australia, $5.50 p&p per order elsewhere.       (Most software is available free on www.siliconchip.com.au). *ZOOM EFI TECH SPECIAL               $A8.95 inc p&p Aust; $11.95 inc p&p elsewhere. *COMPUTER OMNIBUS: $A12.50 inc p&p Australia; NZ/Asia/ Pacific $A15.95 inc p&p (air); elsewhere $18.95 inc p&p (air). *ELECTRONICS TESTBENCH: Aust. $A13.20; NZ/Asia/Pacific $A15.95 inc p&p (air); Elsewhere $18.95. (All prices incl. p&p). *SILICON CHIP/JAYCAR WALLCHART:         Unfolded (in mailing tube): $A9.95 including p&p (Australia only) – unfolded version not available elsewhere. Folded: $A5.95 inc p&p within Australia; elsewhere $A10 inc p&p. *BOOKSHOP TITLES: Please refer to current issue of SILICON CHIP for currently available titles and prices as these may vary from month to month. SUBSCRIBERS QUALIFY FOR 10% DISCOUNT ON ALL SILICON CHIP PRODUCTS AND SERVICES* *except subscriptions/renewals and Internet access Item Price Qty Item Description P&P if extra Total Price Spec i SUB al Offer SCR IBE & COM PUTE GET R OM FO N Aust R FREE! IBUS ralia Only* Total $A TO PLACE YOUR ORDER Phone (02) 9979 5644 9am-5pm Mon-Fri Please have your credit card details ready OR Fax this form to (02) 9979 6503 with your credit card details 24 hours 7 days a week OR Mail this form, with your cheque/money order, to: Silicon Chip Publications Pty Ltd, PO Box 139, Collaroy, NSW, Australia 2097 * Special offer applies while stocks last. 09-01 VINTAGE RADIO By RODNEY CHAMPNESS, VK3UG Healing R401E/S401E Mantel Radio A. G. Healing of Melbourne made radios and TV sets for many years. They varied from quite simple units to reasonably elaborate ones. They never appeared to strive for the top end of the market, being content to stick with good, middle of the market equipment. The 401E 4-valver is a basic little mantel receiver de­ signed for areas where signals are reasonably strong. It is quite an attractive little unit in a brown Bakelite case, with the speaker grille on the left and the dial on the right. The dial has “Golden Voice” in its centre which was part of Healing’s trademark. It has two controls, volume and tuning. It has no on/off switch, the wall switch being required to do the job. It could be considered a miniature mantel receiver, although some sets of the era (1948) were smaller. The above-chassis view is filled with components, except for the power transformer and rectifier valve which are recessed below the chassis. It appears that provision was made to have a card type cover for the back, for other sets using this cabinet. This model apparently didn’t have a back, as the spots where the cover would The simple design of this Healing set extended to the gold-painted dial drum with the pointer printed directly onto it. 84  Silicon Chip have attached to the cabinet had never been drilled to take securing screws. Consequently, the set is easily removed from its cabinet, by undoing two screws along the bottom edge of the chassis at the back and taking the two knobs off. The set is then slid out of the cabinet but like many small radios, the dial scale and speaker remain in the cabinet. This makes it awkward so I length­ened the speaker leads, so that I could more easily service the set without having to remove the speaker from the cabinet. The dial light is also attached to the cabinet via a slip-in socket but it is easily removed. For a long life, the dial light runs from a 4.5V tap on the 6.3V filament winding of the power transformer. One interesting little point – there is a spigot protruding from the inside of the front of the cabinet that acts as a locating pin for the chassis. It stops the chassis from moving around inside the cabinet, seeing as it is only held in place by two screws at the back. The dial drive consists of a drum driven from a rubber grommet drive via dial cord. The grommet is a tight fit over the brass tuning shaft. The dial drum is a gold colour and there is a straight black line painted across it to act as the “pointer”. This is elegantly simple and works very effectively. The two operational controls are fitted the opposite way to normal, with the tuning control on the left and the volume control on the right. They could easily be swapped around, and maybe some sets were built with the controls arranged in the conventional manner. I am not a fan of deep chassis construction such as this example. Relatively speaking, it is not too deep at 55mm but being a narrow chassis, www.siliconchip.com.au Fig.1: simplicity is the keynote of this 4-valve super­het made by A. G. Healing. Not shown on this circuit is the filter choke which has its frame connected to the HT rail. care is needed in accessing some points. Some manufacturers seemed to believe that a deep chassis gave them the right to put layer upon layer of components in, just to keep things nice and compact. Pity the poor person who had to service the sets. Hot filter choke The filter choke is hidden underneath the chassis and just as well. It is mounted on an insulated fibre board and its frame is connected to the high tension (HT) line. This was done to minimise the voltage between the winding and the frame. This technique was used to help prevent electrolysis eating through the winding at some spot. Speaker transformers of this era were quite prone to the primary winding going open circuit and were often mounted so that the transformer frame was at HT too. Howev­er, this is the first time I’ve seen it used with a filter choke. The circuit shown has a dropping resistor instead of a choke, so it would appear that various modifications were done to the model throughout its production life. Servicing the 401E Being such a simple receiver, it is not hard to get it up and running. Most www.siliconchip.com.au paper capacitors were replaced as they were most likely leaky. The only ones I considered essential to re­place were C3, C11 and C13. However, the circuit is remarkably tolerant of slightly leaky capacitors in all locations. This cannot be said of many other receivers. All resistors bar one were within tolerance. The electrolytic capacitors were changed and a new 3-core power cord was fitted and a clamp attached to secure it in place. Knotting the power cable to prevent it being pulled out of the chassis is not an approved method these days. So if you do replace a mains cable, clamp it to the chassis with a metal or plastic clamp; it keeps the authorities happier. Having replaced the components most likely to give trouble (paper capacitors in particular), a resistor and the mains cord to the set, it was time to give it a go. I went through my usual Hiding under the chassis, adjacent to the 4.7µF 500VW capacitor, is the filter choke with its frame tied to the HT. This could give a nasty shock to the unsuspecting repairer. September 2001  85 These rear views of the set show how the power transformer is recessed right into the deep chassis. procedure of checking for any shorts in the power transformer, across the high tension line to earth and that the speaker trans­former had continuity in the primary winding. All was well. Power was connected and the set warmed up but its perfor­mance was not good. I do have a few replacement valves and by the nature of the problem and measurement of the cathode to earth voltage on the 6V6GT, it was obvious all was not well. The vol­ tage was not the designed 12V, so a replacement was tried. The set then 86  Silicon Chip sounded a lot healthier. Other than the alignment nothing else needed attention. Alignment The set is quite easily aligned. As the circuit has no automatic gain control (AGC), all adjustments can be done for maximum volume out of the speaker, provided you have a signal generator. If you have no signal generator, the best method is to connect a digital multimeter (DMM), set to a low voltage DC range, across R6 the detector load. A normal analog (moving coil) multimeter will unfortunately load the circuit too much and the readings are not likely to deflect the pointer sufficiently up the scale. Connect a reasonable aerial to the set. Tune to a strong radio station and with a small screwdriver, adjust the primary and secondary windings of the IF transformers L3 and L4 for maxi­mum reading on the meter. The volume control setting will affect the readings on the meter. You may not have the IF tuned to 455kHz but it should be close unless someone has been twiddling the adjustments. This is the easy part of the job. The alignment of the oscillator and aerial circuits is a little more complex. Place the chassis back into the cabinet and make sure that when the gang is closed, the black pointer line lines up square through the Healing name. If it doesn’t, adjust the drum on the gang spindle until it does. With the set in the cabinet, tune to a strong station that you know around 600kHz. If you are fortunate, the station will come in on the appropriate station marker on the dial. If not, put the dial on the station mark on the dial and withdraw the chassis from the cabinet. Now adjust C7 until the station coincides with the dial marking. All being well, you’ll be able to get the station tuned in accurately. Then adjust the core in L1 for maximum reading on the meter. The next step is to tune to a station around 1500kHz that you can easily recognise and once again, having identified the station, turn the dial until the correct station identification has the dial pointer behind it. Note: a few years ago, some sta­tions changed their frequencies and the markings on the dial may not be anywhere near where they were in times gone by. For exam­ple, 3NE moved from 1600kHz to 1566kHz, so older dial scales are no longer accurate. Leave the dial pointer coinciding with the station dial marking. Adjust C4 to hear the station, then adjust C1 for maximum volume and meter reading. The adjustments of the aerial and oscillator circuits interact with one another from one end of the dial to the other. Hence it will be necessary to go over the adjustments a couple of times to get the alignment as close as is practical. Having to slide the chassis in www.siliconchip.com.au Photo Gallery: Astor OZ “Mickey Mouse” Looking for an old valve? or a new valve? BUYING - SELLING - TRADING Australasia's biggest selection Also valve audio & guitar amp. books SSAE DL size for CATALOGUE Manufactured by Radio Corporation Pty Ltd in 1934, the Astor Model OZ “Mickey Mouse” was housed in an attractive veneered wooden cabinet and was the first of a long series of small sets to carry the “Mickey Mouse” and, later, “Mickey” name. The circuit was a straight 5-valve superheter­ odyne with an IF (intermediate frequency) of 455kHz and included the following valves: 6A7 frequency changer; 6D6 IF amplifier; 6B7 detector, AVC rectifier and audio amplifier; 43 audio output stage; and 25Z5 rectifier. The set was fitted with a 5-inch electrodynamic loudspeaker. A feature of this unit is its low HT voltage – just 130V – hence the choice of a type 43 output valve. This gave cooler running in the small cabinet. Photo Gallery: Astor “Mickey Grand” ELECTRONIC VALVE & TUBE COMPANY PO Box 487 Drysdale, Victoria 3222. Tel: (03) 5257 2297; Fax: (03) 5257 1773 Mob: 0417 143 167; email: evatco<at>mira.net Premises at: 76 Bluff Road, St Leonards, Vic 3223 been completely maladjusted, it is unlikely that this simple method will achieve the results necessary to get optimum performance out of the set. In fact, if the alignment is way off, you may not be able to hear any signals from the set. This can be compounded if there are defective valves in the set too. How does it operate Manufactured by Radio Corporation Pty Ltd in 1935, the Astor Model MZ “Mickey Grand” was housed in an attractive mini-console cabinet measuring just 380mm high. It used the same basic 5-valve super­het­ er­o­dyne chassis as the “Mickey Mouse” but was fitted with a larger loudspeaker (6-inch vs. 5-inch). As with the “Mickey Mouse”, this set also operated with an IF of 455kHz and a HT voltage of just 130V. and out of the cabinet to do this job is a real drag, but there is no alternative when the dial scale is attached to the cabinet. Once this procedure has been comwww.siliconchip.com.au pleted, it is desirable to seal the cores and trimmer screws with some plastic cement or nail polish to stop them shifting out of adjustment. If the tuned circuit adjustments have The performance of small 4-valve radios is never expected to be marvellous. However, many do surprise me and the performance of this little set is very good, rivalling a number of 5-valve sets. Obviously, Healing got the design of their coils and IF transformers close to optimum, to obtain the performance it does have. There is no AGC so it is necessary to adjust the volume control as you tune across the band, as strong stations will blast you and weak ones require the volume control to be advanced for reasonable volume. A set like this would not be good in areas where radio signals fade up and down due to this lack of AGC. However, it is designed for strong signal areas so this is prob­ SC ably not a great deficiency. September 2001  87 w  So you have spent countless hours developing a project and now you would like to see it published for all the world to see. Does SILICON CHIP accept articles for publication? Yes, we do. Here are some general guidelines to anyone contemplating writing articles for SILICON CHIP. W ant to write for SILICON CHIP? You do? Great. Before you start, let's give you some general guidelines which will make your job easier and will greatly increase the chances that the article will be accepted for publication. Before you start on that great article concept, please contact us to find out whether it is of interest to the readers. We would hate it if you had put in an enormous amount of work to produce an article only to find that we reject it because it is not of sufficient interest to the readers. There may be other reasons for rejection, of course: we might have a similar article ready or almost ready for publication – or we might have already given another person the go-ahead for a similar idea. When you contact us, we will ask you for the general concept. If it is a project, we will want to see a circuit diagram and a brief synopsis on what it does, how it works and how much it might cost. We'd also need to know that any specialised components you have used will be available for other readers to obtain. Perhaps you would like to submit a feature article. Again, we would like a synopsis; ie, a brief outline of the article. You can contact us by phone or mail but if you can do it by email, please do. Contact us at silchip<at>siliconchip.com.au When emailing, please do NOT attach documents in HTML format. If you wrote your synopsis in Word or another text editor, leave it that way. Opening HTML documents simply takes extra time. What about money? Yes, we do pay for published articles but there are conditions which we will spell out when you contact us. We generally do not commission articles. We always edit submitted articles and often end up doing substantial re-writes. The amount we have to do affects the overall payment. Submitting the article itself These days, we like articles to be submitted as (preferably) Word documents or .txt files on a Zip disk, CD-ROM or floppy 88  Silicon Chip disk, formatted for PCs. You can also email articles to us. If you do email us an article, please do it as a text file or as an attached Word file. Any Word attachments you send to us should be virus checked beforehand. Speaking of viruses, we get a lot of them sent to us in various ways. If you need to send .exe files or zip files please make sure that you run them through the latest virus software such as Norton Anti-Virus. Contributors get very embarrassed when we subsequently inform them that they have a virus. As a general policy we, like most companies these days, immediately delete any email that comes in with an attached .exe file unless we know (and trust!) the source. By the way, we often find viruses in submitted material but the contributor swears on a stack of Bibles that they virus check everything. It's only after a bit of quizzing that we find they haven't updated their virus definitions or signatures for months, perhaps years. Please update regularly! Article format Please don't make your article look pretty. We want it in plain, unadorned text. These days, since so many people have Microsoft Word or similar word processing software, there is a great temptation for writers to use fancy fonts and formats, dropped caps, italics, bullets, indented paragraphs, text in various colours and so on. Don't bother! No matter how fancy your document looks, all that effort in presentation will be dumped because if we do publish it, it will be formatted to suit the magazine. So whether we like your article or not, we have no choice but to dump your formatting. We are only interested in your basic text. For the same reasons, please do not present your article as a PDF file, a Powerpoint presentation or as files from any desktop package such as Pagemaker, Quark Express, Publisher, etc. We only have to extract the text back out again which once again will lose all your fancy formatting. Fancy formatting also makes your article much harder to edit and you want to make our job easy, don't you? OK, maybe you need to include some tables in your article. In that case, we will need the table format (eg, in Word) but please don't send them as Excel or database files. All of that sounds like a lot of negatives but we really need to keep the whole process simple and that means text files or Word document files. By the way, regardless of which word processor program you use, they all have a facility for outputting your article as a .txt file (also known as ASCII or plain text). Do not just change the file extension and hope for the best – the chances are that we won't be able to read it. That is one really good aspect of email. If you send us an article inserted as a text file, you will be able to read it on the screen, before you click on the “send” button. Still on word processors: if you have Microsoft Word it is a good idea to make full use of its grammar and spell-checking capabilities. Make sure you have the English dictionary loaded, not the American. Also, it is a good idea to use Word's readability statistics after you have run a spell check. If you want to make your article as readable as possible, keep the sentences and paragraphs reasonably short. Try to make sentences active, not passive and not too wordy. If the Word “Flesch-Reading Ease” score is below 40 (out of 100), you know you have a problem. Photographs and graphics As you can see from most of the articles in SILICON CHIP, we generally like to include plenty of photos and diagrams. So what to do? While some people do go to the trouble of taking photos of their projects, they are rarely good enough for publication. We much prefer to take our own photos and for that reason (and also to check the operation of your project) we generally prefer to have the prototype submitted to us. We do return prototypes, whether or not the article is published. We know there are times when it may be www.siliconchip.com.au  SILICON CHIP impractical or impossible to send us your project and therefore you wish to take your own photos. We work in 35mm format only and prefer colour transparencies (ie, so-called colour slides). The sharper they are, the better. It does not matter to us if the slide is mounted or unmounted (but unmounted cost you less to have processed); if unmounted, please do not cut slides into individual frames. Most “neg files” hold a strip of 6 negatives or transparencies – that's fine for us. By the way, send us all the frames you shoot – we like to choose the best exposures, best focus and best framing, ourselves. We don't want 2-1/4-inch square or larger format transparencies, as we then have to out-source the scanning which can delay publication. If you only have colour prints, send us the colour negatives as well. We scan the latter as they have far more detail, contrast and colour than any colour print. If you want to take your own photos, you really need a single-lens reflex 35mm camera with separate control over aperture, exposure time and focus. And while modern, automatic cameras might be great for happy-snaps of your family on holidays, they are really not suitable for magazine photography because you have no control over aperture and depth of field. If you are taking photos of your project, vintage radio or whatever, don't do it on your front lawn, grubby garage floor or against a brick wall. Try to use a neutral background which contrasts with the object you are photographing. You can use a plain or light pastel bedsheet, but make sure it is spotless and has been carefully ironed to take out the creases – remember that the camera will ruthlessly record any blemishes. Remember also that any shiny surfaces on the object being photographed will pick up the background (foreground) colour and can give unwanted colour casts. Speaking of unwanted colour casts, taking photos under fluorescent light will give a greenish cast while incandescent lighting will give a red cast. Direct sunlight will give very strong shadows which can conceal www.siliconchip.com.au detail while indirect sunlight can give an overall blue cast. Can't win, can you? Well, you can, but it is best to be aware of all the traps. The best light – by far – is outdoors with a lightly overcast sky. Shadows will be minimised or even eliminated and the light is virtually pure white. But sometimes you don't get those overcast days without the rain pouring down! That is why it is preferable to send us the project and we'll take the photos in our studio. If we mess up, we have to do it again! Digital photos Digital cameras have come a long way in recent times but the majority are still not good enough for magazine photography. Some high-end digital cameras which have a resolution of at least 3 megapixels (4 is better) and which also allow you to control aperture, exposure and focus can produce good results (the cover photo on the August 2001 issue of SILICON CHIP was shot "natural light" with a 3.3 megapixel digital camera outdoors on a cloudy day). Photographs shot on a digital camera need to be done at the camera's highest possible resolution. Many digital cameras store photos at 72dpi. This is OK if the image size is very large but not if it is small. We can manipulate the photo to some degree but only if we have plenty of pixels to start with! As a general rule, if a digital picture will fit on a floppy disk, it will probably NOT be good enough for reproducing in the magazine. There are exceptions, especially where photos are going to be printed very small, but we find that an average compressed photo needs to be at least 2MB to be of much use, particularly where we are going to use it at a reasonable size. If sending pictures by email or on a ZIP disk or CD, you can store them in any recognised format: .EPS, .BMP, .TIF, .JPG, .ZIP, etc – but remember that JPG is a lossy format and .JPG files should not be resampled and restored. ZIPped EPS or TIF are our preferred formats. Scanned photos We would very much prefer to scan any By LEO SIMPSON photos (or other artwork) ourselves. Scanning is an art, especially when it comes to scanning for reproduction in a magazine. Circuit diagrams We need a clear and legible circuit diagram. This can be a pencil sketch or a computer printout but whatever format you provide, we will always redraw it to our standards. If possible, when you draw your circuit diagram stick to the conventions of inputs on the left, outputs on the right, positive supply rails at the top and negative/ground rails at the bottom. You will have noted that we do not use “nF” in our circuit diagrams or descriptions – please convert to µF or pF. Those who are constantly working in electronics understand nF, those who dabble part time are confused by the extra abbreviation. For the same reason, we do not use so-called “metricated” abbreviations for resistors – eg, 1K5 meaning 1.5k or R33 for 33 ohms. Printed circuit boards If you have produced a PC board we prefer that the pattern be drawn in Protel or any version of PC board layout software compatible with Protel: Easytrax, Autotrax, or Circuit Maker. If you design your PC board in another package (eg Eagle, Ivex, etc), we will need an EPS output of each layer – board layer and component layer for a single-sided board. Designing PC boards is a separate topic in itself and we hope to feature an article on this subject shortly. However, as a general rule, keep components more or less evenly spaced on a 50-thou grid (typical) and parallel to the sides of the board; don't have diagonal components – it doesn't look right. Other points to consider: (a) circuit components must be readily available and reasonable in cost. (b) 240VAC wiring must be safe and SC comply with all relevant codes. September 2001  89 REFERENCE GREAT BOOKS FOR DIGITAL ELECTRONICS – A PRACTICAL APPROACH AUDIO POWER AMP DESIGN HANDBOOK By Douglas Self. 2nd Edition Published 2000 By Richard Monk. Published 1998. From one of the world’s most respected audio authorities. The new 2nd edition is even more comprehensive, includes sections on load-invariant power amps, distortion residuals and diagnosis of amplifier problems.368 pages in paperback. 85 $$ $$ 65 With this book you can learn the principles and practice of digital electronics without leaving your desk, through the popular simulation applications, EASY-PC Pro XM and Pulsar. Alternatively, if you want to discover the applications through a thoroughly practical exploration of digital electronics, this is the book for you. A free floppy disk is included, featuring limited function versions of EASY-PC Professional XM and Pulsar. 249 pages, in paperback. VIDEO SCRAMBLING AND DESCRAMBLING for Satellite & Cable AUDIO ELECTRONICS If you've ever wondered how they scramble video on cable and satellite TV, this book tells you! Encoding/decoding systems (analog and digital systems), encryption, even schematics and details of several encoder and decoder circuits for experimentation. Intended for both the hobbyist and the professional. 290 pages in paperback. This book is for anyone involved in designing, adapting and using analog and digital audio equipment. It covers tape recording, tuners and radio receivers, preamplifiers, voltage amplifiers, audio power amplifiers, compact disc technology and digital audio, test and measurement, loudspeaker crossover systems, power supplies and noise reduction systems. 375 pages in soft cover. By John Linsley Hood. First published 1995. Second edition 1999. TV by Graf & Sheets 75 $ NEW 2nd Edition 1998 3rd W 3rd NE NEW ON:: ITION ED EDITI ME SA SAME ICE!! PR PRICE UNDERSTANDING TELEPHONE ELECTRONICS By Stephen J. Bigelow. Fourth edition published 2001 In keeping With the distinguished tradition of its .. predecessors, Understanding Telephone Electronics, FOURTH EDITION, covers conventional telephone fundamentals, including both analog and modern digital communication techniques. It provides basic information on the functions of each telephone system component, how electronic circuits general dial tones, and how the latest digital transmission techniques work. 59 $$ GUIDE TO TV & VIDEO TECHNOLOGY By Eugene Trundle. First pub­­lished 1988. Second edition 1996. Eugene Trundle has written for many years in Television magazine and his latest book is right up to date on TV and video technology. The book includes both theory and practical servicing information and is ideal for both students and technicians. 382 pages, in paperback. 59 $$ 90  Silicon Chip 99 $ 85 $ EMC FOR PRODUCT DESIGNERS By Tim Williams. First pub­­lished 1992. 3rd edition 2000. Widely regarded as the standard text on EMC, this book provides all the information necessary to meet the requirements of the EMC Directive. It includes chapters on standards, measurement techniques and design principles, including layout and grounding, digital and analog circuit design, filtering and shielding and interference sources. The four appendices give a design checklist and include useful tables, data and formulae. 299 pages, in soft cover. ELECTRIC MOTORS AND DRIVES By Austin Hughes. Second edition published 1993 (reprinted 1997). For non-specialist users – explores most of the widely-used modern types of motor and drive, including conventional and brushless DC, induction, stepping, synchronous and reluctance motors. 339 pages, in paperback. 65 $ www.siliconchip.com.au BOOKSHOP WANT TO SAVE 10%? SILICON CHIP SUBSCRIBERS AUTOMATICALLY QUALIFY FOR A 10% DISCOUNT ON ALL BOOK PURCHASES! ENQUIRING MINDS! (To subscribe, see page 53) ALL PRICES INCLUDE GST PIC Your Personal Introductory Course ANALOG ELECTRONICS NEW NEW NEW NEW NEW NEW by John Morton – 2nd edition 2001 By Ian Hickman. 2nd edition1999. Essential reading for electronics designers and students alike. It will answer nagging questions about core analog theory and design principles as well as offering practical design ideas. With concise design implementations, with many of the circuits taken from Ian Hickman’s magazine articles. 294 pages in soft cover. 85 $ $ TELEPHONE INSTALLATION HANDBOOK by Steve Roberts $ 67 The definitive guide to home and small business installation - extensions, modems and telephone systems. Provides a practical guide to installation of telephone wiring. Ranges from the single extension socket to the Private Automatic Branch Exchange (PABX), with the necessary tools, test equipment and materials needed by installers. 178 pages in soft cover. NEW NEW NEW NEW NEW NEW NEW NEW NEW NEW NEW NEW 43 Concise and practical guide to getting up and running with the PIC Microcontroller. Assumes no NEW prior knowledge of microcon-trollers, introduces the PIC’s cpabilities through NEW simple projects. Ideal introduction for NEW students, teachers, technicians and electronics enthusiasts – perfect for NEW use in schools and colleges. NEW 270 pages in soft cover. NEW VIDEO & CAMCORDER SERVICING AND TECHNOLOGY by Steve Beeching (First published 2001) Provides fully up-to-date coverage of the whole range of current home video equipment, analog and digital. Information for repair and troubleshooting, with explanations of the technology of video equipment. 318 pages in soft cover. SILICON CHIP'S COMPUTER OMNIBUS First published 1999 SILICON CHIP'S ELECTRONICS TEST BENCH First published 2000 Hints, tips, Upgrades and Fixes for your computer from articles published in SILICON CHIP in recent years. Covers DOS, Windows 3.1, 95, 98 and NT. A must for the computer user. $12.50 (Aust); $A15.95 NZ (prices include P&P) O R D E R H E R E P&P A collection of the “most asked for” Test Equipment projects and features from the pages of Australia’s “most asked for” electronics magazine. Exceptional value at $13.20 (Aust); $A15.95 NZ (prices include p&p).  ANALOG ELECTRONICS..................................................$85.00  AUDIO POWER AMPLIFIER DESIGN...............................$85.00  AUDIO ELECTRONICS.....................................................$85.00  DIGITAL ELECTRONICS ..................................................$65.00  ELECTRIC MOTORS AND DRIVES (2ND EDIT)................$65.00  EMC FOR PRODUCT DESIGNERS...................................$99.00  GUIDE TO TV & VIDEO TECHNOLOGY............................$59.00  PIC - YOUR PERSONAL INTRODUCTORY COURSE........$43.00  TELEPHONE INSTALLATION HANDBOOK........................$67.00  UNDERSTANDING TELEPHONE ELECTRONICS.................$65.00  VIDEO & CAMCORDER SERVICING/TECHNOLOGY........$67.00  VIDEO SCRAMBLING/DESCRAMBLING..........................$75.00  SILICON CHIP TEST BENCH.................................... (see above)  SILICON CHIP COMPUTER OMNIBUS.................... (see above)               ORDER TOTAL: $...................... Orders over $100 P&P free in Australia. AUST: Add $A5.50 per book NZ: Add $A10 per book, $A15 elsewhere www.siliconchip.com.au 67 $$ TAX INVOICE Your Name__________________________________________________________ PLEASE PRINT Address ____________________________________________________________ ___________________________________ Postcode_______________ Daytime Phone No. (______) __________________________________ STD Email___________________<at>_________________________________  Cheque/Money Order enclosed OR  Charge my credit card –  Bankcard  Visa Card  MasterCard No: Signature______________________Card expiry date PLUS P&P (if applic): $........................... TOTAL$ AU.............................. POST TO: SILICON CHIP Publications, PO Box 139, Collaroy NSW, Australia 2097. OR CALL (02) 9979 5644 & quote your credit card details; or FAX TO (02) 9979 6503 September 2001  91 ALL TITLES SUBJECT TO AVAILABILITY. PRICES VALID FOR MONTH OF MAGAZINE ISSUE ONLY. ALL PRICES INCLUDE GST INTERNET NEWSGROUP Browsing web pages or search engines is one way to get information off the ’net. But asking a question on an appropriate Newsgroup is often much better. Here are some of the terms you’ll find used – and over the page, many of those mysterious abbreviations! add (also join and subscribe) The act of adding a newsgroup to your personal list of newsgroups. These are the groups that you see when you start up your newsreader. See also: remove. articles that show up – the other articles have expired.) Utility for automatic downloading and processing of binary files, such as images, sounds, or shareware. “include everything under this”) rec.collecting. (recreation groups about collecting) rec.collecting.sport.* recreation groups about sports collecting) rec.collecting.sport.football (a recreation group about sports collecting, specifically football) Note that rec.collecting.sport.* would also include sports collecting groups about baseball, hockey, etc. There are also special, regional, and local hierarchies that may not be available to all people. flame kill file FAQ An individual message in a newsgroup. When a person sends or posts an article and other people reply to it, it forms a thread. (Frequently Asked Questions) A list of answers to Frequently Asked Questions and other useful information for a newsgroup. (When pronouncing, spell it out or rhyme “FAQ” with “back.”) Always read a newsgroup’s FAQ before you post. binary FileGrabber article (also post) A type of newsgroup article that contains encoded binary information, such as a picture, sound, or software application. There are special groups for binary files, such as alt. binaries.clip-art. cancel, cancelbot The act of retracting or removing one’s newsgroup article. Cancelbots are programs that cancel spam posts. charter An angry newsgroup article or e-mail that viciously attacks someone or something. Usually written in the heat of the moment. Often starts a flamewar. Also, the act of sending or posting a flame. A person who flames is a “flamer.” A file used by some newsreaders to reject unwanted articles. A kill file will reject posts containing words, authors, or subjects that you don’t want to see. Also known as a “bozo filter.” (Some newsgroup users signify adding an article or thread to their killfile by replying with the word “*plonk*.”) An official description of what a newsgroup is all about, whether it’s moderated, and what kinds of topics the group will discuss. For specific information about a newsgroup, read the group’s FAQ. flame bait Provocative material in an article that, intentionally or unintentionally, will make people angry and invite flames in response. See trolling. list unread cross-post flame war list all follow up (also reply) lurk To copy an article to multiple newsgroups. Cross-posting should be done sparingly, and only when the post is relevant to the affected newsgroups. Excessive cross-posting is a lot like spam, and is nicknamed “velveeta.” A argument or fight that takes place in newsgroup articles or e-mail. Flamewars involve lots of name-calling, nasty insults, and “YELLING.” delurk To respond to an article by posting a response to the newsgroup. See quoting. To post an article to a newsgroup for the first time. (Just like when a radio-show caller says “Long-time listener, first-time caller.”) See lurk. Emoticon (also smiley) Little faces made out of keyboard characters, used to express smiles :-) winks ;-) surprise :-0 and more. (If you don’t understand the emoticon, put your left ear on your left shoulder and look again!) expired article Newsgroup articles are stored for a limited time, after which they are deleted to make room for new ones. An article that has been deleted and no longer available has “expired.” (This is why the number of articles listed doesn’t always match the number of 92  Silicon Chip header Part of a newsgroup article or e-mail message that contains information needed by the computers that handled it. Hard-to-read but informative,the message ID, date, and time. hierarchy The categories of newsgroups. The main categories are: comp. (computer topics), misc. (miscellaneous), news. (newsgroup-related stuff), rec. (recreation), sci. (science), soc. (society), talk. (discussion), and alt. (alternative). Hierarchies are arranged so they get more specific as you work your way down. For example: rec.* (recreation groups — the “*” means A newsreader command that allows you to see only the messages that you haven’t read before in a given newsgroup. A newsreader command that shows you all the messages in a newsgroup, including messages you have already read (as long as they haven’t expired). To read articles in a newsgroup without posting any of your own. Always lurk a while before posting, to get a feel for the newsgroup. A person who lurks is a “lurker.” See delurk. mark read (also catch up) A newsreader command that marks all the articles in a newsgroup as having been read. Do this after you’ve read the interesting posts in a newsgroup and only want to see new posts the next time you visit. MMF An abbreviation for MAKE MONEY FAST; also the generic name for any of the useless, futile, and often illegal pyramid schemes that promise to “make $5 into $50,000” or “GET RICH QUICK” by spamming newsgroups. www.siliconchip.com.au COMMON TERMS There’s a Newsgroup for every conceivable subject – and then some! If you have Internet access, you almost certainly have Newsgroup access. Ask your ISP if you don’t know how to subscribe. They don’t work, they’re annoying and people will flame you, so don’t ever do it. Posting MMF-type posts is very bad netiquette. moderated newsgroup A newsgroup where all posts must be approved before they can be seen by all. The people who do the filtering are known as moderators. Moderated newsgroups typically have a lot of information, and very little spam or garbage. See signal-to-noise ratio. Netiquette Network etiquette. Since there are no Internet Police, a set of rules and guidelines on acceptable behavior has developed organically. Netiquette includes things like not spamming, learning to lurk before posting, and more. Learn netiquette and you won’t get flamed. newbie A beginner. All experts were newbies once. cause it lets people know what you’re talking about. Quoted material often is preceded by “>” and looks like: > This is an example of quoted material. Here is some more > quoted material, to let people know what you are replying to. This would be where your new comments would begin. reply subscribe A newsgroup article that is posted to the newsgroup as a response to another post. It’s usually a good idea to quote from the article you’re replying to so people know what you’re talking about. When replying, avoid posting simply “me too” or “I agree.” To add a newsgroup to the list of groups you want to read. If you subscribe to a group, that newsgroup will appear every time you open your newsreader. In the vast majority of cases, subscribing is free. See unsubscribe. Request for Discussion (RFD) A test message, usually posted by newbies. Test messages should only be sent to newsgroups specifically designed for this purpose, such as misc.test. Warning: put “Ignore” in your test message’s subject or body, unless you want lots of automatically generated response mail. newsgroup (also group) signal-to-noise ratio newsreader The software you use to access newsgroups. A newsreader lets you read articles, respond to them, and post your own. periodic posting A newsgroup article that is posted to a group or groups at regular intervals. An example of a periodic posting would be a FAQ (list of Frequently Asked Questions) or other helpful information. post A newsgroup article. Also, the act of sending an article to a newsgroup so that others can read and reply to it. quote To include part of a previous post when you follow up to it. Quoting is a good idea be- www.siliconchip.com.au spoiler The newsgroup command to unsubscribe from a newsgroup. remove Another name for newsgroups. Also “Netnews,” “USENET,” or “Usenet.” An Internet discussion forum, such as rec. pets.cats or alt.internet.services. All together, the thousands of newsgroups form a global bulletin board where people talk about every topic imaginable. Newsgroups are where you post articles. used so often that it crowds everything else out. Information that may diminish the enjoyment someone else gets from a book, movie, tv show, etc. Example: Posting “The Titanic sinks!!!” in a current movies newsgroup may spoil someone who hasn’t seen Titanic. Be nice: Use warnings (like adding “SPOILER: Titanic” to the subject line) and add spoiler space (blank lines before spoiler information) to posts that may contain spoilers. An official posting to news.groups that asks for comments and opinions regarding the proposal to create a new newsgroup. Part of the formal newsgroup creation process. news (Sorry – we didn’t mean to yell!) An electronics term used to compare the amount of good, useful info (“signal”) in a newsgroup with the amount of bad, useless junk (“noise”). Newsgroups that have lots of flame wars and spam have a low signal-tonoise ratio. signature (also sig) Text added to the bottom of an article or e-mail to give the reader more information about the poster. Signatures can include e-mail and Web addresses, quotes, text art, and more, though signatures should not be longer than 4 or 5 lines. spam An article that is sent to hundreds or thousands of different newsgroups, and has nothing to do with any of them. Often advertisements or “MAKE MONEY FAST”-type chain letters. Very annoying and a very bad violation of netiquette. The act of sending spam is “spamming.” Someone who sends spam is a “spammer.” The term “spam” comes from the Monty Python sketch where the name of the canned meat product is test thread A thread is an ongoing discussion of related messages that grows from one particular posting. troll A purposely stupid, inflammatory, or downright wrong article (closely related to flamebait). Its purpose is to get people mad and make them look stupid and gullible unsubscribe To remove a newsgroup from your newsreader’s active list. If you unsubscribe, you will no longer see the newsgroup when you open your newsreader. You can always subscribe again. Usenet (also USENET) The full name of newsgroups is “Usenet Newsgroups.” YELLING To yell on a newsgroup, use capitals. Unless you are deliberately yelling, using capitals is considered to be pretty bad Netiquette! September 2001  93 Newsgroup Abbreviations COMMON ABBREVIATIONS COMMON (and many uncommon!) EMOTICONS AFAIK AKA ASAP BTW BRB FAQ FYI FWIW FIIK FUBAR - :-) (-: :-( ;-) #-) =:O :-| ~~:-[ :-$ :-P :-<at> “As Far As I Know” “Also Known As” “As Soon As Possible” “By The Way” “Be Right Back” “Frequently asked questions” “For Your Information” “For What It’s Worth” “. . . If I Know" “. . . Up Beyond All Recognition” GD&R - “Grinning, Ducking and Running (After snide remark) IAEF “If All Else Fails” IANAL - “I Am Not A Lawyer (But...)” IDK “I don’t know” IMHO - “In My Humble Opinion” IMO “In My Opinion” IYKWIM - “If You Know What I Mean” IYKWIMAITYD - “If You Know What I Mean And I Think You Do” LOL “Laughing Out Loud” OK abbreviation of “oll korrect”, alteration of “all correct” OTOH - On The Other Hand PITA “Pain In The Ass” PMFJI - “Pardon Me For Jumping In” PS “Post Script” TIA “Thanks In Advance” TPTB - “The Powers That Be” TTFN - “Ta Ta For Now” ROTFL - “Rolling On The Floor Laughing” RTFM - “Read The . . . Manual SOHF - “Sense Of Humor Failure” SWALK - “Sealed With A Loving Kiss” WRT “With Respect To” WYSIWYG - “What You See Is What You Get” YMMV - “Your Mileage May Vary” (You may not have the same luck I did) YWIA - “You’re Welcome In Advance” AFK = away from keyboard BAK = back at keyboard BRB = be right back WB = welcome back GMTA = great minds think alike WTG = way to go RSI = repetitive strain injury 94  Silicon Chip Happy Left Handed/Australian Sad Winky Oh, what a night! Yelling/Shocked Frowning Net Flame Put Your Money Where Your Mouth Is Sticking Out Tongue Screaming/Swearing/Very Angry/ About To Be Sick :*) Drunk/Clown :-# Been Smacked In The Mouth/ Wears A Brace/Kiss R -) Broken Glasses (:-) Bald :-))) Is Very Fat :-{} Wears Lipstick =:-) A Dickhead <at>:-) Wears A Turban $-) Yuppie/Just Won A Large Sum Of Money :,( Crying : =) Two Noses 8:] Gorilla 8-) Wears Glasses B:-) Wears Sun Glasses On Head :-T Keeping A Straight Face/Tight Lipped :-y Said With A Smile :-| Disgusted/Grim/No Expression :~-( Crying/Shed A Tear :’-( Crying :~(~~ Crying :-Q A Smoker :-! A Smoker %-\ Has A Hangover |-o Bored :-X A Kiss/Lips Are Sealed (:-D Has A Big Mouth (:+) Has A Big Nose :-{) Has A Moustache :-* Just Ate Something Sour/Bitter Taste/Kiss [:-) Is Wearing A Walkman (:-) Bicycle Helmets :-)’ Tends To Drool =:-) Punk +-:-) The Pope O:-) An Angel *<:-)> Santa o-<:-{{{ Santa *<|:-) Santa/A Clown 5:-) Elvis Presley :-% Banker :-: Mutant Smiley (-:|:-) Siamese Twins :-) 7:-) Fred Flinstone :/7) Cyrano de Bergerac C):-O C):-O C):-O C):-O A Barbershop Quartet 3:-o A Cow 8:-) A Pig/A Little Girl :\/ A Woodpecker ]:-> The Devil ,-) A One Eyed Winky |-( Lost Contact Lenses #:-) Matted Hair/Fur Hat/Crewcut/ Messy Hair &:-) Curly Hair C=:-) A Chef <at>}->— A Rose =|:-)= Uncle Sam/Abe Lincoln 7:) Ronald Reagan +<:-| Monk/Nun :_) A Boxer/Had a Fight { A Psycho (:I An Egghead b:-) A Baseball Fan/Has A Cap On (-) Needs A Haircut ;-(*) Feels Sick *****:-) Marge Simpson [:] A Robot :-[ A Vampire/Count Dracula/Pouting/ Sarcastic :-F A Bucktoothed Vampire/Has Major Dental Problems :=) Orangutan/Has Two Noses :-? Smokes A Pipe :-8( Condescending 8-# Death/Dead ;^) Smirking :——} Liar/Pinnochio !-( Black Eye ) Cheshire Cat (:-D Blabber Mouth > A Schizo *#*!^*&:-) phrenic :-’| Has A Cold/Flu :$) Donald Trump :-.) Marilyn Monroe/Madonna :-) 8 Dolly Parton :-|:-| Deja’vu <*:oDX A Clown C|:-= Charlie Chaplin : .) Cindy Crawford =) Adolf Hitler ~:o A Baby ===:-D Don King 8(:-) Mickey Mouse/Walt Disney (|-| F Robocop 3:*> Rudolph the Reindeer P-) A Pirate %-~ Picasso ‘:-) Has One Eyebrow SC www.siliconchip.com.au DON’T UTER COMP MISS OMNIBUS THE ’BUS! www.siliconchip.com.au SILICON CHIP’S 132 Pages $ 95 * 9 ISBN 0 95852291 X 9780958522910 09 9 780958 522910 IN LINCLUDES FEA U TUR X E A collection of computer features from the pages of SILICON CHIP magazine Hints o Tips o Upgrades o Fixes Covers DOS, Windows 3.1, 95, 98, NT o RT Do you feel a little “left behind” by the latest advances and developments in computer hardware and software? Don’t miss the bus: get the ’bus! THIS IS IT: The computer reference you’ve been asking for! SILICON CHIP's Computer Omnibus is a valuable compendium of the most-requested computer hardware and software features from recent issues of SILICON CHIP magazine - all in one handy volume. Here's just a sample of the contents: Troubleshooting your PC: what to do when things go wrong NO Choosing, installing and taming computer networks AVA W Upgrading and overclocking CPUs DIRE ILABLE C Hard disk drive upgrades, tune-ups and tips SILIC T FROM Windows 3.1, 95, 98 and NT tips and tricks ON just $ CHIP The Y2K Bug - and how to swat it 125O* INC All about Linux GST & P& P And much more!!! ORDER NOW: Use the handy order form in this issue or call www.siliconchip.com.au September 2001  95 (02) 9979 5644, 9-5 Mon-Fri with your credit card details. * Price includes GST 09 Silicon Chip Back Issues April 1989: Auxiliary Brake Light Flasher; What You Need to Know About Capacitors; 32-Band Graphic Equaliser, Pt.2. May 1989: Build A Synthesised Tom-Tom; Biofeedback Monitor For Your PC; Simple Stub Filter For Suppressing TV Interference. July 1989: Exhaust Gas Monitor; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm; The NSW 86 Class Electrics. September 1989: 2-Chip Portable AM Stereo Radio (Uses MC13024 and TX7376P) Pt.1; High Or Low Fluid Level Detector; Studio Series 20-Band Stereo Equaliser, Pt.2. September 1993: Automatic Nicad Battery Charger/Discharger; Stereo Preamplifier With IR Remote Control, Pt.1; In-Circuit Transistor Tester; +5V to ±15V DC Converter; Remote-Controlled Cockroach. October 1993: Courtesy Light Switch-Off Timer For Cars; Wireless Microphone For Musicians; Stereo Preamplifier With IR Remote Control, Pt.2; Electronic Engine Management, Pt.1. May 1991: 13.5V 25A Power Supply For Transceivers; Stereo Audio Expander; Fluorescent Light Simulator For Model Railways; How To Install Multiple TV Outlets, Pt.1. July 1991: Loudspeaker Protector For Stereo Amplifiers; 4-Channel Lighting Desk, Pt.2; How To Install Multiple TV Outlets, Pt.2; Tuning In To Satellite TV, Pt.2. September 1991: Digital Altimeter For Gliders & Ultralights; Ultrasonic Switch For Mains Appliances; The Basics Of A/D & D/A Conversion; Plotting The Course Of Thunderstorms. October 1989: FM Radio Intercom For Motorbikes Pt.1; GaAsFet Preamplifier For Amateur TV; 2-Chip Portable AM Stereo Radio, Pt.2. October 1991: Build A Talking Voltmeter For Your PC, Pt.1; SteamSound Simulator For Model Railways Mk.II; Magnetic Field Strength Meter; Digital Altimeter For Gliders, Pt.2; Military Applications Of R/C Aircraft. November 1989: Radfax Decoder For Your PC (Displays Fax, RTTY & Morse); FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM Stereo Radio, Pt.3; Floppy Disk Drive Formats & Options. November 1991: Colour TV Pattern Generator, Pt.1; A Junkbox 2-Valve Receiver; Flashing Alarm Light For Cars; Digital Altimeter For Gliders, Pt.3; Build A Talking Voltmeter For Your PC, Pt.2. January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR; Phone Patch For Radio Amateurs; Active Antenna Kit; Designing UHF Transmitter Stages. December 1991: TV Transmitter For VCRs With UHF Modulators; Infrared Light Beam Relay; Colour TV Pattern Generator, Pt.2; Index To Volume 4. February 1990: A 16-Channel Mixing Desk; Build A High Quality Audio Oscillator, Pt.2; The Incredible Hot Canaries; Random Wire Antenna Tuner For 6 Metres; Phone Patch For Radio Amateurs, Pt.2. January 1992: 4-Channel Guitar Mixer; Adjustable 0-45V 8A Power Supply, Pt.1; Baby Room Monitor/FM Transmitter; Experiments For Your Games Card. March 1990: Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16-Channel Mixing Desk, Pt.2; Using The UC3906 SLA Battery Charger IC. March 1992: TV Transmitter For VHF VCRs; Thermostatic Switch For Car Radiator Fans; Coping With Damaged Computer Directories; Valve Substitution In Vintage Radios. April 1990: Dual Tracking ±50V Power Supply; Voice-Operated Switch (VOX) With Delayed Audio; 16-Channel Mixing Desk, Pt.3; Active CW Filter; Servicing Your Microwave Oven. April 1992: IR Remote Control For Model Railroads; Differential Input Buffer For CROs; Understanding Computer Memory; Aligning Vintage Radio Receivers, Pt.1. June 1990: Multi-Sector Home Burglar Alarm; Build A Low-Noise Universal Stereo Preamplifier; Load Protector For Power Supplies. June 1992: Multi-Station Headset Intercom, Pt.1; Video Switcher For Camcorders & VCRs; IR Remote Control For Model Railroads, Pt.3; 15-Watt 12-240V Inverter; A Look At Hard Disk Drives. July 1990: Digital Sine/Square Generator, Pt.1 (covers 0-500kHz); Burglar Alarm Keypad & Combination Lock; Build A Simple Electronic Die; A Low-Cost Dual Power Supply. August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Mains Appliances (9 Minutes); Horace The Electronic Cricket; Digital Sine/Square Generator, Pt.2. September 1990: A Low-Cost 3-Digit Counter Module; Build A Simple Shortwave Converter For The 2-Metre Band; The Care & Feeding Of Nicad Battery Packs (Getting The Most From Nicad Batteries). October 1990: The Dangers of PCBs; Low-Cost Siren For Burglar Alarms; Dimming Controls For The Discolight; Surfsound Simulator; DC Offset For DMMs; NE602 Converter Circuits. November 1990: Connecting Two TV Sets To One VCR; Build An Egg Timer; Low-Cost Model Train Controller; 1.5V To 9V DC Converter; Introduction To Digital Electronics; A 6-Metre Amateur Transmitter. December 1990: 100W DC-DC Converter For Car Amplifiers; Wiper Pulser For Rear Windows; 4-Digit Combination Lock; 5W Power Amplifier For The 6-Metre Amateur Transmitter; Index To Volume 3. \January 1991: Fast Charger For Nicad Batteries, Pt.1; Have Fun With The Fruit Machine (Simple Poker Machine); Build A Two-Tone Alarm Module; The Dangers of Servicing Microwave Ovens. November 1993: High Efficiency Inverter For Fluorescent Tubes; Stereo Preamplifier With IR Remote Control, Pt.3; Siren Sound Generator; Engine Management, Pt.2; Experiments For Games Cards. December 1993: Remote Controller For Garage Doors; Build A LED Stroboscope; Build A 25W Audio Amplifier Module; A 1-Chip Melody Generator; Engine Management, Pt.3; Index To Volume 6. 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: Build A 90-Second Message Recorder; 12-240VAC 200W Inverter; 0.5W Audio Amplifier; 3A 40V Adjustable Power Supply; Engine Management, Pt.5; Airbags In Cars – How They Work. March 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. April 1994: Sound & Lights For Model Railway Level Crossings; Discrete Dual Supply Voltage Regulator; Universal Stereo Preamplifier; Digital Water Tank Gauge; Engine Management, Pt.7. 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. June 1994: 200W/350W Mosfet Amplifier Module; 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. July 1994: Build A 4-Bay Bow-Tie UHF TV Antenna; PreChamp 2-Transistor Preamplifier; Steam Train Whistle & Diesel Horn Simulator; 6V SLA Battery Charger; Electronic Engine Management, Pt.10. August 1994: High-Power Dimmer For Incandescent Lights; Microprocessor-Controlled Morse Keyer; Dual Diversity Tuner For FM Microphones, Pt.1; Nicad Zapper (For Resurrecting Nicad Batteries); Electronic Engine Management, Pt.11. August 1992: Automatic SLA Battery Charger; Miniature 1.5V To 9V DC Converter; 1kW Dummy Load Box For Audio Amplifiers; Troubleshooting Vintage Radio Receivers; The MIDI Interface Explained. September 1994: Automatic Discharger For Nicad Battery Packs; MiniVox Voice Operated Relay; Image Intensified Night Viewer; AM Radio For Weather Beacons; Dual Diversity Tuner For FM Microphones, Pt.2; Electronic Engine Management, Pt.12. October 1992: 2kW 24VDC - 240VAC Sinewave Inverter; Multi-Sector Home Burglar Alarm, Pt.2; Mini Amplifier For Personal Stereos; A Regulated Lead-Acid Battery Charger. October 1994: How Dolby Surround Sound Works; Dual Rail Variable Power Supply; Build A Talking Headlight Reminder; Electronic Ballast For Fluorescent Lights; Electronic Engine Management, Pt.13. January 1993: Flea-Power AM Radio Transmitter; High Intensity LED Flasher For Bicycles; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.4; Speed Controller For Electric Models, Pt.3. November 1994: Dry Cell Battery Rejuvenator; Novel Alphanumeric Clock; 80-Metre DSB Amateur Transmitter; Twin-Cell Nicad Discharger (See May 1993); How To Plot Patterns Direct to PC Boards. February 1993: Three Projects For Model Railroads; Low Fuel Indicator For Cars; Audio Level/VU Meter (LED Readout); An Electronic Cockroach; 2kW 24VDC To 240VAC Sinewave Inverter, Pt.5. December 1994: Easy-To-Build 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. March 1993: Solar Charger For 12V Batteries; Alarm-Triggered Security Camera; Reaction Trainer; Audio Mixer for Camcorders; A 24-Hour Sidereal Clock For Astronomers. January 1995: Sun Tracker For Solar Panels; Battery Saver For Torches; Dolby Pro-Logic Surround Sound Decoder, Pt.2; Dual Channel UHF Remote Control; Stereo Microphone Pre­amp­lifier. April 1993: Solar-Powered Electric Fence; Audio Power Meter; Three-Function Home Weather Station; 12VDC To 70VDC Converter; Digital Clock With Battery Back-Up. February 1995: 50-Watt/Channel Stereo Amplifier Module; Digital Effects Unit For Musicians; 6-Channel Thermometer With LCD Readout; Wide Range Electrostatic Loudspeakers, Pt.1; Oil Change Timer For Cars; Remote Control System For Models, Pt.2. June 1993: AM Radio Trainer, Pt.1; Remote Control For The Woofer Stopper; Digital Voltmeter For Cars; Windows-Based Logic Analyser. March 1991: Transistor Beta Tester Mk.2; A Synthesised AM Stereo Tuner, Pt.2; Multi-Purpose I/O Board For PC-Compatibles; Universal Wideband RF Preamplifier For Amateur Radio & TV. July 1993: Single Chip Message Recorder; Light Beam Relay Extender; AM Radio Trainer, Pt.2; Quiz Game Adjudicator; Windows-Based Logic Analyser, Pt.2; Antenna Tuners – Why They Are Useful. April 1991: Steam Sound Simulator For Model Railroads; Simple 12/24V Light Chaser; Synthesised AM Stereo Tuner, Pt.3; A Practical Approach To Amplifier Design, Pt.2. August 1993: Low-Cost Colour Video Fader; 60-LED Brake Light Array; Microprocessor-Based Sidereal Clock; A Look At Satellites & Their Orbits. March 1995: 50 Watt Per Channel 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; Simple CW Filter. April 1995: FM Radio Trainer, Pt.1; Photographic Timer For Dark­ rooms; Balanced Microphone Preamp. & Line Filter; 50W/Channel Stereo Amplifier, Pt.2; Wide Range Electrostatic Loudspeakers, Pt.3; 8-Channel Decoder For Radio Remote Control. ORDER FORM Please Pleasesend sendthe thefollowing followingback backissues: issues:      ____________________________________________________________ Enclosed is my cheque/money order for $­______or please debit my: ❏ Bankcard ❏ Visa Card ❏ Master Card Card No. Signature ___________________________ Card expiry date_____ /______ Name ______________________________ Phone No (___) ____________ PLEASE PRINT Street ______________________________________________________ Suburb/town _______________________________ Postcode ___________ 96  Silicon Chip 10% OF F SUBSCR TO IB OR IF Y ERS OU 10 OR M BUY ORE Note: prices include postage & packing Australia ....................... $A7.70 (incl. GST) Overseas (airmail) ............................ $A10 Detach and mail to: Silicon Chip Publications, PO Box 139, Collaroy, NSW, Australia 2097. Or call (02) 9979 5644 & quote your credit card details or fax the details to (02) 9979 6503. Email: silchip<at>siliconchip.com.au www.siliconchip.com.au May 1995: Build A 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. 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. 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. December 1997: Speed Alarm For Cars; 2-Axis Robot w/Gripper; Loudness Control For Car Hifi Systems; Stepper Motor Driver With Buffer; Power Supply For Stepper Motor Cards; Understanding Electric Lighting Pt.2. 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. January 1998: Build Your Own 4-Channel Lightshow, Pt.1 (runs off 12VDC or 12VAC); Command Control System For Model Railways, Pt.1; Pan Controller For CCD Cameras; Build A One Or Two-Lamp Flasher; Understanding Electric Lighting, Pt.3. August 1995: Fuel Injector Monitor For Cars; Gain Controlled Microphone Preamp; Audio Lab PC-Controlled Test Instrument, Pt.1; How To Identify IDE Hard Disk Drive Parameters. September 1995: Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.1; Keypad Combination Lock; The Vader Voice; Jacob’s Ladder Display; Audio Lab PC-Controlled Test Instrument, Pt.2. October 1995: 3-Way Bass Reflex Loudspeaker System; Railpower Mk.2 Walkaround Throttle For Model Railways, Pt.2; Fast Charger For Nicad Batteries; Digital Speedometer & Fuel Gauge For Cars, Pt.1. November 1995: Mixture Display For Fuel Injected Cars; CB Trans­verter For The 80M Amateur Band, Pt.1; PIR Movement Detector; Digital Speedometer & Fuel Gauge For Cars, Pt.2. 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. February 1998: Multi-Purpose Fast Battery Charger, Pt.1; Telephone Exchange Simulator For Testing; Command Control System For Model Railways, Pt.2; Build Your Own 4-Channel Lightshow, Pt.2; Understanding Electric Lighting, Pt.4. April 1998: Automatic Garage Door Opener, Pt.1; 40V 8A Adjustable Power Supply, Pt.1; PC-Controlled 0-30kHz Sinewave Generator; Build A Laser Light Show; Understanding Electric Lighting; Pt.6. May 1998: Troubleshooting Your PC, Pt.1; Build A 3-LED Logic Probe; Automatic Garage Door Opener, Pt.2; Command Control For Model Railways, Pt.4; 40V 8A Adjustable Power Supply, Pt.2. June 1998: Troubleshooting Your PC, Pt.2; Understanding Electric Lighting, Pt.7; Universal High Energy Ignition System; The Roadies’ Friend Cable Tester; Universal Stepper Motor Controller; Command Control For Model Railways, Pt.5. December 1999: Electric Lighting, Pt.16; Build A Solar Panel Regulator; The PC Powerhouse (gives fixed +12V, +9V, +6V & +5V rails); The Fortune Finder Metal Locator; Speed Alarm For Cars, Pt.2; Railpower Model Train Controller, Pt.3; Index To Volume 12. January 2000: Spring Reverberation Module; An Audio-Video Test Generator; Build The Picman Programmable Robot; A Parallel Port Interface Card; Off-Hook Indicator For Telephone Lines. February 2000: Multi-Sector Sprinkler Controller; A Digital Voltmeter For Your Car; An Ultrasonic Parking Radar; Build A Safety Switch Checker; Build A Sine/Square Wave Oscillator; Marantz SR-18 Home Theatre Receiver (Review); The “Hot Chip” Starter Kit (Review). March 2000: Doing A Lazarus On An Old Computer; Ultra Low Distortion 100W Amplifier Module, Pt.1; Electronic Wind Vane With 16-LED Display; Glowplug Driver For Powered Models; The OzTrip Car Computer, Pt.1; Multisim Circuit Design & Simulation Package (Review). April 2000: A Digital Tachometer For Your Car; RoomGuard – A LowCost Intruder Alarm; Build A Hot wire Cutter; The OzTrip Car Computer, Pt.2; Build A Temperature Logger; Atmel’s ICE 200 In-Circuit Emulator; How To Run A 3-Phase Induction Motor From 240VAC. May 2000: Ultra-LD Stereo Amplifier, Pt.2; Build A LED Dice (With PIC Microcontroller); Low-Cost AT Keyboard Translator (Converts IBM Scan-Codes To ASCII); 50A Motor Speed Controller For Models. June 2000: Automatic Rain Gauge With Digital Readout; Parallel Port VHF FM Receiver; Li’l Powerhouse Switchmode Power Supply (1.23V to 40V) Pt.1; CD Compressor For Cars Or The Home. January 1996: Surround Sound Mixer & Decoder, Pt.1; Magnetic Card Reader; Build An Automatic Sprinkler Controller; IR Remote Control For The Railpower Mk.2; Recharging Nicad Batteries For Long Life. July 1998: Troubleshooting Your PC, Pt.3 (Installing A Modem And Solving Problems); Build A Heat Controller; 15-Watt Class-A Audio Amplifier Module; Simple Charger For 6V & 12V SLA Batteries; Automatic Semiconductor Analyser; Understanding Electric Lighting, Pt.8. April 1996: Cheap Battery Refills For Mobile Telephones; 125W Audio Amplifier Module; Knock Indicator For Leaded Petrol Engines; Multi-Channel Radio Control Transmitter; Pt.3; Cathode Ray Oscilloscopes, Pt.2. August 1998: Troubleshooting Your PC, Pt.4 (Adding Extra Memory); Build The Opus One Loudspeaker System; Simple I/O Card With Automatic Data Logging; Build A Beat Triggered Strobe; A 15-Watt Per Channel Class-A Stereo Amplifier. August 2000: Build A Theremin For Really Eeerie Sounds; Come In Spinner (writes messages in “thin-air”); Loudspeaker Protector & Fan Controller For The Ultra-LD Stereo Amplifier; Proximity Switch For 240VAC Lamps; Structured Cabling For Computer Networks. September 1998: Troubleshooting Your PC, Pt.5 (Software Problems & DOS Games); A Blocked Air-Filter Alarm; A Waa-Waa Pedal For Your Guitar; Build A Plasma Display Or Jacob’s Ladder; Gear Change Indicator For Cars; Capacity Indicator For Rechargeable Batteries. September 2000: Build A Swimming Pool Alarm; An 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 1996: Upgrading The CPU In Your PC; High Voltage Insulation Tester; Knightrider Bi-Directional LED Chaser; Simple Duplex Intercom Using Fibre Optic Cable; Cathode Ray Oscilloscopes, Pt.3. June 1996: BassBox CAD Loudspeaker Software Reviewed; Stereo Simulator (uses delay chip); Rope Light Chaser; Low Ohms Tester For Your DMM; Automatic 10A Battery Charger. July 1996: Build A VGA Digital Oscilloscope, Pt.1; Remote Control Extender For VCRs; 2A SLA Battery Charger; 3-Band Parametric Equaliser; Single Channel 8-Bit Data Logger. 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. October 1998: Lab Quality AC Millivoltmeter, Pt.1; PC-Controlled Stress-O-Meter; Versatile Electronic Guitar Limiter; 12V Trickle Charger For Float Conditions; Adding An External Battery Pack To Your Flashgun. November 1998: The Christmas Star; A Turbo Timer For Cars; Build A Poker Machine, Pt.1; FM Transmitter For Musicians; Lab Quality AC Millivoltmeter, Pt.2; Setting Up A LAN Using TCP/IP; Understanding Electric Lighting, Pt.9; Improving AM Radio Reception, Pt.1. September 1996: VGA Oscilloscope, Pt.3; IR Stereo Headphone Link, Pt.1; High Quality PA Loudspeaker; 3-Band HF Amateur Radio Receiver; Cathode Ray Oscilloscopes, Pt.5. December 1998: Protect Your Car With The Engine Immobiliser Mk.2; Thermocouple Adaptor For DMMs; A Regulated 12V DC Plugpack; Build Your Own Poker Machine, Pt.2; Improving AM Radio Reception, Pt.2; Mixer Module For F3B Glider Operations. October 1996: Send Video Signals Over Twisted Pair Cable; Power Control With A Light Dimmer; 600W DC-DC Converter For Car Hifi Systems, Pt.1; IR Stereo Headphone Link, Pt.2; Build A Multi-Media Sound System, Pt.1; Multi-Channel Radio Control Transmitter, Pt.8. January 1999: High-Voltage Megohm Tester; Getting Started With BASIC Stamp; LED Bargraph Ammeter For Cars; Keypad Engine Immobiliser; Improving AM Radio Reception, Pt.3; Electric Lighting, Pt.10. November 1996: Adding A Parallel Port To Your Computer; 8-Channel Stereo Mixer, Pt.1; Low-Cost Fluorescent Light Inverter; How To Repair Light Dimmers; 600W DC-DC Converter For Car Hifi Systems, Pt.2. February 1999: Installing A Computer Network; Making Front Panels For Your Projects; Low Distortion Audio Signal Generator, Pt.1; Command Control Decoder For Model Railways; Build A Digital Capacitance Meter; Build A Remote Control Tester; Electric Lighting, Pt.11. December 1996: Active Filter Cleans Up Your CW Reception; A Fast Clock For Railway Modellers; Laser Pistol & Electronic Target; Build A Sound Level Meter; 8-Channel Stereo Mixer, Pt.2; Index To Volume 9. January 1997: How To Network Your PC; Control Panel For Multiple Smoke Alarms, Pt.1; Build A Pink Noise Source; Computer Controlled Dual Power Supply, Pt.1; Digi-Temp Monitors Eight Temperatures. February 1997: Cathode Ray Oscilloscopes, Pt.6; PC-Con­trolled Moving Message Display; Computer Controlled Dual Power Supply, Pt.2; Loud Sounding Telephone Alarm; Control Panel For Multiple Smoke Alarms, Pt.2. March 1997: Driving A Computer By Remote Control; Plastic Power PA Amplifier (175W); Signalling & Lighting For Model Railways; Build A Jumbo LED Clock; Cathode Ray Oscilloscopes, Pt.7. 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. March 1999: Getting Started With Linux; Pt.1; Build A Digital Anemometer; 3-Channel Current Monitor With Data Logging; Simple DIY PIC Programmer; Easy-To-Build Audio Compressor; Low Distortion Audio Signal Generator, Pt.2; Electric Lighting, Pt.12. 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; Electric Lighting, Pt.13; Autopilots For Radio-Controlled Model Aircraft. May 1999: The Line Dancer Robot; An X-Y Table With Stepper Motor Control, Pt.1; Three Electric Fence Testers; Heart Of LEDs; Build A Carbon Monoxide Alarm; Getting Started With Linux; Pt.3. June 1999: FM Radio Tuner Card For PCs; X-Y Table With Stepper Motor Control, Pt.2; Programmable Ignition Timing Module For Cars, Pt.1; Hard Disk Drive Upgrades Without Reinstalling Software? 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. July 1999: Build A Dog Silencer; 10µH to 19.99mH Inductance Meter; Build An Audio-Video Transmitter; Programmable Ignition Timing Module For Cars, Pt.2; XYZ Table With Stepper Motor Control, Pt.3. June 1997: PC-Controlled Thermometer/Thermostat; Colour TV Pattern Generator, Pt.1; Audio/RF Signal Tracer; High-Current Speed Controller For 12V/24V Motors; Manual Control Circuit For A Stepper Motor. 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. 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. August 1997: The Bass Barrel Subwoofer; 500 Watt Audio Power Amplifier Module; A TENs Unit For Pain Relief; Addressable PC Card For Stepper Motor Control; Remote Controlled Gates For Your Home. September 1997: Multi-Spark Capacitor Discharge Ignition; 500W Audio Power Amplifier, Pt.2; A Video Security System For Your Home; PC Card For Controlling Two Stepper Motors; HiFi On A Budget. October 1997: Build A 5-Digit Tachometer; Add Central Locking To Your Car; PC-Controlled 6-Channel Voltmeter; 500W Audio Power Amplifier, Pt.3; Customising The Windows 95 Start Menu. www.siliconchip.com.au September 1999: Automatic Addressing On TCP/IP Networks; 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. October 1999: Sharing A Modem For Internet & Email Access (WinGate); 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. November 1999: Electric Lighting, Pt.15; Setting Up An Email Server; Speed Alarm For Cars, Pt.1; Multi-Colour LED Christmas Tree; Build An Intercom Station Expander; Foldback Loudspeaker System For Musicians; Railpower Model Train Controller, Pt.2. July 2000: A Moving Message Display; Compact Fluorescent Lamp Driver; El-Cheapo Musicians’ Lead Tester; Li’l Powerhouse Switchmode Power Supply (1.23V to 40V) Pt.2; Say Bye-Bye To Your 12V Car Battery. October 2000: Guitar Jammer For Practice & Jam Sessions; Booze Buster Breath Tester; A Wand-Mounted Inspection Camera); Installing A Free-Air Subwoofer In Your Car; Fuel Mixture Display For Cars, Pt.2; Protoboards – The Easy Way Into Electronics, Pt.2. November 2000: Santa & Rudolf Chrissie Display; 2-Channel Guitar Preamplifier, Pt.1; Message Bank & Missed Call Alert; Electronic Thermostat; Protoboards – The Easy Way Into Electronics, Pt.3. December 2000: Home Networking For Shared Internet Access; Build A Bright-White LED Torch; 2-Channel Guitar Preamplifier, Pt.2 (Digital Reverb); Driving An LCD From The Parallel Port; Build A morse Clock; Protoboards – The Easy Way Into Electronics, Pt.4; Index To Vol.13. January 2001: LP Resurrection – Transferring 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; Wireless Networking. February 2001: How To Observe Meteors Using Junked Gear; An Easy Way To Make PC Boards; L’il Pulser Train Controller; Midi-Mate – A MIDI Interface For PCs; Build The Bass Blazer; 2-Metre Elevated Groundplane Antenna; The LP Doctor – Clean Up Clicks & Pops, Pt.2. March 2001: Driving Your Phone From A PC; Making Photo Resist PC Boards At Home; Big-Digit 12/24 Hour Clock; Parallel Port PIC Programmer & Checkerboard; Protoboards – The Easy Way Into Electronics, Pt.5; More MIDI – A Simple MIDI Expansion Box. April 2001: A GPS Module For Your PC; Dr Video – An Easy-To-Build Video Stabiliser; A Tremolo Unit For Musicians; Minimitter FM Stereo Transmitter; Intelligent Nicad Battery Charger; Computer Tips – Tweaking Internet Connection Sharing. May 2001: Powerful 12V Mini Stereo Amplifier; Microcontroller-Based 4-Digit Counter Modules; Two White-LED Torches To Build; A Servo With Lots Of Grunt; PowerPak – A Multi-Voltage Power Supply; Using Linux To Share An Internet Connection, Pt.1; Computer Tips – Tweaking Windows With TweakUI. June 2001: Fast Universal Battery Charger, Pt.1; Phonome – Call, Listen In & Switch Devices On & Off; L’il Snooper – A low-Cost Automatic Camera Switcher; Build a PC Games Port Tester; Using Linux To Share An Internet Connection, Pt.2; A PC To Die For, Pt.1. July 2001: The HeartMate Heart Rate Monitor; Do Not Disturb Tele­ phone Timer; Pic-Toc – A Simple Alarm Clock; Fast Universal Battery Charger, Pt.2; A PC To Die For, Pt.2; Computer Tips – Backing Up Your Email; Digital Amplifiers Are Here (Feature). August 2001: Direct Injection Box For Musicians; Build A 200W Mosfet Amplifier Module; Headlight Reminder For Cars; 40MHz 6-Digit Frequency Counter Module; A PC To Die For, Pt.3; Using Linux To Share An Internet Connection, Pt.3. PLEASE NOTE: November 1987 to March 1989, June 1989, August 1989, December 1989, May 1990, February 1991, June 1991, August 1991, February 1992, July 1992, September 1992, November 1992, December 1992, May 1993, February 1996 and March 1998 are now sold out. All other issues are presently in stock. For readers wanting articles from sold-out issues, we can supply photostat copies (or tear sheets) at $7.70 per article (includes p&p). When supplying photostat articles or back copies, we automatically supply any relevant notes & errata at no extra charge. A complete index to all articles published to date is available on floppy disk for $11 including p&p, or can be downloaded free from our web site: www.siliconchip.com.au September 2001  97 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 How do servos work I understand the basics of the theory of proportional radio control but have you ever published an article about what the inside of a servo looks like? Obviously, the servo plugs straight into the receiver of the radio control unit but I was wondering what the motor is like, what limits its movement, etc. (B. T., via email). • We published an article on servos, including an exploded diagram, in the March 1991 issue. We represented the article in November 1997. Power rating for speed controller I built your motor speed controller from the November 1997 issue (Dick Smith Electronics kit). It works well in testing but I haven’t loaded it up yet. I notice in the inset titled “What Motors Can Be Controlled?” you state that the controller is only suitable for “intermittently used power tools”. I guess that means it’s not rated for continuous use. What is the duty cycle Can SLA batteries be topped up? Some time ago, I built the Mk1 version of your Universal Battery Charger and have a few queries: (1) I have a 6V 5Ah SLA lantern battery which I have difficulty in charging. The charger 100% LED will light when this battery is connected, even if it is discharged. (2) It is not recommended to top up Nicad batteries because of the “memory effect”. However, is it possible to do this with an SLA battery so that my lantern torch is always on maximum capaci­ty when I take it away on trips? (3) I am interested in radio control modelling and use my charger to charge transmitter (9.6V), receiv98  Silicon Chip of the controller? (C. C., via email). Our article makes no mention of intermittent use. Provided the case does not get hot to the touch, there is no reason why it cannot be used continuously. • Bigger transformer for 500W amplifier I was just wondering about the limitations of the 500W amplifier designed back in August, September & October 1997. The reason I’m interested is that I bought eight of these from Jaycar as an investment. At the time, I didn’t have the cash for the power supply but I now have the funds to finally finish these pieces of art. However, I have noticed that the original 800VA (57V-0-57V) toroidals are no longer available. Would two 500VA (65V-065V) do the trick for each amplifier? Considering these toroidals have a higher voltage, would I need capacitors with a higher voltage capacity? Would higher capacitance help as well? I’m not expecting huge gains from the amplifier; just another 50100W of headroom. Will the amplifi­ er (4.8V) and field packs (7.2V). I would like to be able to use the charger in the field. Therefore, is it possible for you to design a modification for both Mk1 and Mk2 models to operate from a 12V car battery? (D. M., via email). • The Mk1 version of the charger sometimes had problems with particular cells or batteries. Your charging problem could be solved by upgrading to the Mk2 version. You can top up SLA batteries as these are “sealed lead acid” chemistry and do not have the Nicad memory effect. The charger is not suitable for operating on 12VDC as the circuit has been optimised for use with raw DC (from a transform­er and bridge rectifier). er drive 2-ohm loads with the higher spec components? (M. G., Gle­norie, NSW). • First, you cannot substitute a transformer with 65V windings as this will increase the amplifier supply rails to over 90V and increase the overall amplifier dissipation by 30%! We suggest you contact Harbuch Electronics on (02) 9476 5854. They can wind suitable transformers to order. We do not recommend operation with 2-ohm loads as it will exceed the safe operating area ratings (SOAR) of both the output transistors and the driver transistors – see Fig.2, page 27 of the August 1997 issue. Tone controls for bass guitar I had success in assembling the guitar preamp and a 120W power amplifier and was delighted that it worked first time. The unit is for a bass guitar for my son and this is where my ques­ tion arises. Can you supply me with substitute values for the tone control stage to suit a bass guitar? I am not sure what the treble and bass mid-points are but possibly 400Hz and 4kHz? (J. P., via email). • We don’t know which guitar preamplifier you assembled: the January 1992 design or the November 2000 design. Either way, we would not change the tone control. There is very little treble from a bass guitar and increasing the treble boost will only increase the residual noise. Nor would we change the bass crosso­ver as it is likely to lead to premature overload. Parts for 24V battery charger I have been searching for a suitable 24V battery charger for some restored railway carriages and have found the “Automatic 10 Amp Charger” in the June 1996 issue. There are no suppliers for this project and some of the components are proving difficult to source. They are: www.siliconchip.com.au (1) “E-type ferrite transformer with bobbin, Jaycar LF-1270 or similar”. The current product with that Jaycar Cat. No. is an inductor and not the said transformer. (2) ETD 29 transformer assembly. (3) BYV32-200. I presume there is an updated equivalent but not sure how critical it is. (R. P., via email). • The ETD29 is available from Farnell Electronics. Their catalog number is 305-6375 for each core (2 required), 178-506 for the bobbin and 178-507 for clips (2 required). The T1 transformer is not available from Jaycar now. You could use an EFD25 which will almost fit in the PC board holes but redrilling the holes will allow this to be used. The Farnell catalog numbers for this are 200-300 for the cores (2 required), 200-311 for bobbin and 200-323 for clips (2 required). The BYV32-200 is also available from Farnell. The Cat. number is 250-650. Is CDI dangerous for a motor bike? I built the HEI (high energy ignition) kit for my Falcon not too long ago. I am very impressed with it. Now I would like to try something different and build the Multi-Spark Capacitor Discharge Ignition (CDI) described in September 1997, for a motor bike. I have a few problems that you may have answers for. The bike that I would like to put this on has a 4-cylinder 250cc 16-valve engine. My main concern is that it is such a small engine and the high energy spark may arc to the aluminium head and damage it in the long term. The spark plugs under the normal twin-coil system produce a rather pathetic spark at higher revs. In the workshop manual for my 1994 Ford Falcon it says that the EGO sensor has an output from 0.33V to 1.1V. Can I am building the Digital Fuel Dis- I tune the meter for this and do I make the span from 0.33V to 1.1V instead play described in the September & of 0V to 1V? Also, will this change October 2000 issues of SILICON CHIP. In the instruction section for cali- the lambda to a different value? (B. brating the air/fuel meter, it describes B., via email). the procedure for setting the trimpots • You can set the span and offset for a Bosch EGO sensor with an out- to 1.1V and 330mV if you need to. put of 0-1V. It also states that if you However, the actual curve shape will have the output specs for the EGO still follow the Bosch sensor as prosensor in your car you can trim these grammed. A complete curve match 80x181mm.qxd 3/5/01 11:37 AM Page 1 would require adjusting the curve pots to suit. Calibrating the digital fuel mixture display Spark plug sizes are somewhat smaller than that of a car. The cylinder has a small 30mm stroke. Peak revs are at 17,000 rpm after which it redlines to 19,500 rpm. The cylinder configuration is two up, two down; ie, two outer cylinders up while the two centre cylinders are down. They fire in a 1 3 4 2 sequence. Do you have any comments or suggestions? • While the CDI does have high energy, the actual spark vol­ tage depends on the cylinder pressure. When the engine is under load, the cylinder pressures are higher and the voltage across the spark plug will rise to a higher voltage before it fires. But there is no danger of damage to the cylinder heads, even if there was an arc-over, which is highly unlikely. lookup table in the program. The 0.6V stoichiometric point should not change much with a different offset voltage. How to wind coils with enamelled wire I have a quick query on the MiniMitter (April 2001) that I am currently constructing. I am not quite sure how to construct coils L1 and L2. Does the enamelled copper wire need to be soldered to the pins on the former? If Meterman. The Working Man’s Meter. Meters that fit your job. Meters that fit your wallet. Introducing Meterman, a hot new brand of test and measurement tools that gives you the performance you need at a price you can afford. Meterman is a line of more than 60 meters, clamps, and testers. Each one designed with the right combination of features, functions and accuracy to fit your application. You work hard on the job. Get the tool that’s easy on your wallet. Ask your local test and measurement supplier for the Meterman products or contact Meterman on Locked Bag 5004 Baulkham Hills NSW 2153, phone 02 8853 8812 or fax 02 8850 3300, or visit metermantesttools.com TM www.siliconchip.com.au September 2001  99 Kit wanted for rust prevention On many occasions when I have been to car shows, I have seen a product that prevents rust by electronic means. These units are generally housed in a small aluminium case and are only about the size of cassette for a motorbike and double that size for standard vehicle. They connect to the frame and use the 12V wiring from the vehicle. I absolutely have no idea how it is possible to completely stop rust, especially by electronic means! If they work as well as the representatives say, I would like to know whether it is feasible to make a kit that would do the same job? I’d assume it would be a popular kit, espe­cially for those of us that own older “non plas­tic” cars. so, how is this done? I have tried unsuccessfully, only managing to deform the foot of the former with the heat. (I. C., via email). • We generally give fairly detailed info on winding coils but this time we forgot. You have to scrape the enamel off the copper wire before you can solder to it. Scrape it off, tin it with solder and then solder it to the pins on the coil form­ers. Gas sensor project Did you ever feature a gas detector in your magazine? A fellow worker seems to think he saw one in one of your magazines. (M. M., via email). • We published a carbon monoxide (exhaust gas) monitor in the July 1989 and May 1999 issues. We also Also, it has been seven months since I converted my Ford XC V8 to the High Energy Ignition plus Hall Effect sensor system. It has been the best investment that I have made on the car so far! The engine is extremely smooth and quiet on idling. I dare say that the fuel economy would compare to the latest engines found in 4WD and bigger family wagons! (A. P., via email). • We do not believe these electronic rust preventers can work since they do not involve a sacrificial anode. In any event, they are usually fitted by dealers to new cars (gives them extra profit) and since new cars take years to rust, few people would complain that the rust preventer does not work. Glad the HEI works well – it certainly does make engines much smoother. published a breath tester in October 2000. We can supply these issues for $7.70 each including postage. BASIC is still free In “Ask Silicon Chip” for the July 2001 issue, you stated that GWBASIC/ QBASIC interpreters were supplied free until DOS 6. In fact, Microsoft freely supplies the MS-DOS 6.22 version of QBASIC, together with on-line help, in the \other\oldmsdos folder of the Win95 CD. I suspect that the Win98 CD may also include it. Another interesting Win95B freebie is HwDiag.exe which is found in the \other\misc\hwtrack folder. (F. Z., via email). • Oops, you’re right. On the Win98 CD, it’s in the \tools\oldmsdos folder. The two files required are QBASIC.EXE and QBASIC.HLP. Updating the multi-purpose charger I previously built the original Fast Multi-Purpose Battery Charger as described in the February & March 1998 issues of SILICON CHIP. I now want to update it to your new design but I am a bit confused about the winding of the main switching inductor L1. In your original design, you require 10 turns bifilar wound of 1mm copper wire, thus a total of 20 turns of wire. In your latest design, you call for 20 turns bifilar wound which, by my interpretation of Fig.3 on p70 of the July 2001 issue, would make a total of 40 turns. Which is the correct number of turns to use? (B. H., New Town, Tas). • You can leave the number of turns on L1 as per the original version. (10 turns). The circuit will operate with either winding setup. Clifford the cricket is mute I am building Clifford the Cricket, as described in the December 1994 issue. I have put all the components in correctly and have also tried replacing the IC and both transistors but the circuit still refuses to work. The LEDs light but the buzzer just provides a low constant clicking sound. I have checked the buzzer and it seems OK. Can you suggest anything? (C. M., via email). • The oscillator for the piezo buzzer is possibly too fast for any chirping sound to be heard. Try changing the .047µF capacitor between pins 8 & 9 of IC1 to a larger value. A 0.22µF capacitor might be a good start. Also, the flashing rate for the LEDs can be varied by adjusting the 2.2µF capacitor value 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. 100  Silicon Chip www.siliconchip.com.au More information on the PIC Testbed I have some questions on the PIC Testbed pub­lished in the January 2001 issue. I know that I have successfully downloaded the program (.asm file) to the testbed (16F84). I assume that I need to set the jumper on the testbed for the clock when programming and I know that the pro­gram was down­loading to the chip (by connecting the LEDs when programming. By the way, if the LEDs are left connected when programming, the chip will not program successfully). But I am unsure as to how to set the program in motion when it is downloaded. Also, I have questions on the COM port on the board. I tried to use the COM port (built onto the board) before realising that it was nearly pointless doing so as it is not supported by any of the software I have tried so far and also because of the differences in support protocol. at pins 11 & 12 of IC1. A larger value will slow down the rate. A smaller value will speed it up. Deep cycle vs auto batteries I’m under the impression that cartype 4WD starter batter­ ies do not like being drained of more than 20% of their capacity. I think that they where intended for starting only and not stor­age. As I have a 4WD and no extra battery, I thought a deep-cycle battery might be better. That way, more Notes & Errata 12/24 Hour Giant Clock, March 2001: as published, in the 24-hour mode the clock changes from 23.59.59 to 24.00.00. This is now changed to the correct 24-hour transition from 23.59.59 to 00.00.00. The upgraded software is called clock1.asm and clock1.hex and is available on the SILICON CHIP website. DI Box, August 2001: the tip contact and integral switch contact in the DC jack socket on the circuit on page 14 are shown reversed; ie, the tip contact www.siliconchip.com.au (M. C., via email). • The program should run (meaning the LEDs should chase) as soon as you disconnect the programming adapter cable and press the reset button. From your description, we assume you have selected the 4MHz crystal as the clock source, which is the correct option for the DEMO & TESTBED programs. We have recently updated the little DEMO & TESTBED pro­grams, as well as created a slightly modified version that will work with the RC oscillator. Regarding the serial port, you’re quite correct in your assumption that you need to download a program to drive the port. A good starting point might be a little terminal program that receives characters from the serial input line and displays them on the LCD. You will find numerous examples to get you started on the ‘net. Check out Microchip’s application notes first at www.microchip.com capacity can be used without damage to the battery. I know that a deep cycle battery would be more expensive. (G. M., via email). • As a general rule, all car and truck batteries have a very poor life expectancy if they are frequently subject to heavy discharge. In normal conditions, the vehicle alternator takes all the electrical load and so the battery does little except for its starting role which normally only causes a brief and very shallow discharge. If you are having electrical problems, the solution may be to install a bigger alternator. should go to switch S1 while the integral switch contact should go to the battery negative. The wiring diagram on page 16 is correct. The parts list on page 19 does not include VR5 which should be a 16mm 10kΩ linear potentiometer. Also the testing instructions on page 19 do not tell how to adjust VR5. To do so, connect a DMM across the bass pot VR2 and adjust VR5 for zero DC voltage. This eliminates any DC current through the bass control and stops it from becoming noisy. SC SMART FASTCHARGERS® 2 NEW MODELS WITH OPTIONS TO SUIT YOUR NEEDS & BUDGET Now with 240V AC + 12V DC operation PLUS fully automatic voltage detection Use these REFLEX® chargers for all your Nicads and NIMH batteries: Power tools  Torches  Radio equip.  Mobile phones  Video cameras  Field test instruments  RC models incl. indoor flight  Laptops  Photographic equip.  Toys  Others  Rugged, compact and very portable. Designed for maximum battery capacity and longest battery life. AVOIDS THE WELL KNOWN MEMORY EFFECT. SAVES MONEY & TIME: Restore most Nicads with memory effect to capacity. Recover batteries with very low remaining voltage. CHARGES VERY FAST plus ELIMINATES THE NEED TO DISCHARGE: charge standard batteries in minimum 3 min., max. 1 to 4 hrs, depending on mA/h rating. Partially empty batteries are just topped up. Batteries always remain cool; this increases the total battery life and also the battery’s reliability. DESIGNED AND MADE IN AUSTRALIA For a FREE, detailed technical description please Ph (03) 6492 1368; Fax (03) 6492 1329; or email: smartfastchargers<at>bigpond.com 2567 Wilmot Rd., Devonport, TAS 7310 P.C.B. Makers ! • • • • • • • • If you need: P.C.B. High Speed Drill 3M Scotchmark Laser Labels P.C.B. Material – Negative or Positive acting Light Box – Single or Double Sided – Large or Small Etch Tank – Bubble Electronic Components and Equipment for TAFEs, Colleges and Schools Prompt and Economical Delivery FREE ADVICE ON ANY OF OUR PRODUCTS FROM DEDICATED PEOPLE WITH HANDS-ON EXPERIENCE We now stock Hawera Carbide Tool Bits KALEX 40 Wallis Ave E. Ivanhoe 3079 Ph (03) 9497 3422 FAX (03) 9499 2381 ALL MAJOR CREDIT CARDS ACCEPTED September 2001  101 MARKET CENTRE Cash in your surplus gear. Advertise it here in Silicon Chip. YES! FRWEEBE Place your classified advertisement in SILICON CHIP Market Centre and your advert will also appear FREE in the Classifieds-on-the-Web page of the SILICON CHIP website, www.siliconchip.com.au And if you include an email address or your website URL in you classified advert, the links will be LIVE in your classified-on-the-web! S! D E I F I S C LAS EXCLUSIVE TO SILICON CHIP! CLASSIFIED ADVERTISING RATES Advertising rates for this page: Classified ads: $20.00 (incl. GST) for up to 20 words plus 66 cents for each additional word. Display ads: $33.00 (incl. GST) per column centimetre (max. 10cm). Closing date: five weeks prior to month of sale. To run your classified ad, print it clearly in the space below or on a separate sheet of paper, fill out the form & send it with your cheque or credit card details to: Silicon Chip Classifieds, PO Box 139, Collaroy, NSW 2097. Or fax the details to (02) 9979 6503. Taxation Invoice ABN 49 003 205 490 _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Enclosed is my cheque/money order for $­__________ or please debit my ❏ Bankcard   ❏ Visa Card   ❏ Master Card Card No. Signature­­­­­­­­­­­­__________________________ Card expiry date______/______ Name ______________________________________________________ Street ______________________________________________________ Suburb/town ___________________________ Postcode______________ 102  Silicon Chip FOR SALE SEE-in-the-DARK Camera with in-built IR LEDs in Water Resistant Case for disturbance-free Baby - Bird - Animal observation from $147 * NEW Wireless Version available NOW!* www.allthings.com.au TELEPHONE EXCHANGE SIMULATOR: test equipment without the cost of telephone lines. Melb 9806 0110. http://www.alphalink.com.au/ ~zenere CCTV Cameras * up to 770 + H-Line Resolution * High 0.02 lux Sensitivity * Extraordinary 58 + dB Signal : Noise Ratio * SUPER WIDE 275 + Dynamic Range * Incredible 150 + dB Smear Rejection * Modules - Mini - Domes - C Mount - CS Mount – Wireless * www.allthings.com.au oatleyelectronics.com LIMITED STOCK!!! ALMOST NIGHT VISION IN A CCD CAMERA. THESE HIGH-QUALITY USED IKEGAMI CAMERAS with 1/2 ccd image transfer system, 570 lines res. Will produce good noise free pics in sub moon-light. With a variety of lenses... Canon electronic 10-100mm Zoom / auto iris... STD Fixed length with auto iris... STD fixed Large and mid-sized pan & tilt units. Large and mid-sized weather-proof camera housings, some temperature controlled, some with window wipers. Don’t forget to check out our new kits and subscribe to our new kits mailing list. PC Surveillance Digital-Video-Recording Web-Cam Remote-View Dial-In Dial-Out Paging 768 x 576 Resolution software $149 Sept only! www.allthings.com.au WEATHER STATIONS: Windspeed & direction, inside temperature, outside temperature & windchill. Records highs & lows with time and date as they occur. Optional rainfall and PC interface. Used by Government Departments, farmers, www.siliconchip.com.au Covert CCTV PCB Modules – Mini Cams - in PIR Case or Detector from $113 / $173 Mono / Colour www.allthings.com.au KITS KITS AND MORE KITS! Check ‘em out at www.ozitronics.com VGA-VIDEO Converter from $139 display PC / MAC images on Large Screen TV / LCD Projector - Record on a VCR - Ideal for Games - DVD - Presentations – Create Software Tutorial Videos www.allthings.com.au GO TO www.questronix.com.au for video equipment, information, techo links and monthly specials. CCTV Quads from $154 / $276 Mono / Colour 4 pixs 1 screen www.allthings.com.au UNIVERSAL DEVICE PROGRAMMER: Low cost, high performance, 48-pin, works in DOS or Windows inc NT/2000. $1320. Universal EPROM programmer $429. Also adaptors, (E) EPROM, PIC, 8051 programmers, EPROM simulator and eraser. Dunfield C Compilers: Everything you need to develop C and ASM software for 68HC08, 6809, 68HC11, 68HC12, 68HC16, 8051/52, 8080/85, 8086, 8096 or AVR: $198 each. Demo disk available. ImageCraft C Compilers: 32-bit Windows IDE and compiler. For AVR, 68HC11, 68HC12. $396. Atmel Flash CPU Programmer: Handles the 89Cx051, 89C5x, 89Sxx in both DIP and PLCC44 and some AVR’s, most 8-pin EEPROMS. Includes socket for serial ISP cable. $220, $11 p&p. SOIC adaptors: 20 pin $99, 14 pin $93.50, 8 pin $88. Full details on web site. Credit cards accepted. GRANTRONICS PTY LTD, PO Box 275, Wentworthville 2145. (02) 9896 7150 or http://www.grantronics.com.au HOME CCTV Mono / Colour PAKS www.siliconchip.com.au ROLA AUSTRALIA PH/FAX (08) 8270 3175 • • • • WEB SITE WWW.BETTANET.NET.AU/GTD Model Flight Control Modules CHECK OUR WEBSITE FOR DETAILS ON KITS AND COMPONENTS TRANSMITTER KITS AND MODULES AUDIO MODULES COMPUTER INTERFACE KITS RADIO STATION AUDIO SOFTWARE NEW: Our MP3-CD player in short form for $169 inc GST. Includes the following: processor board, front panel display and tactile keypad; just add a case, cables, 12V power supply and a CD-ROM drive. Play CDs and up to 2600 MP3’s from a CDR. Great for car or home. Satellite TV Reception International satellite TV reception in your home is now affordable. Send for your free info pack containing equipment catalog, satellite lists, etc or call for appointment to view. We can display all satellites from 76.5° to 180°. AV-COMM P/L, 24/9 Powells Rd, Brookvale, NSW 2100. Tel: 02 9939 4377 or 9939 4378. Fax: 9939 4376; www.avcomm.com.au PDC 01 SERIAL INTERFACE $198.60 PDC 10 GPS INTERFACE MODULE $398.00 PDC 20 ALTITUDE HOLD MODULE $498.00 PDC25 SPEED HOLD MODULE $498.00 PDC 400 ALTIMETER AIR-DATA SENSOR $398.40 PDC 450 AIRSPEED-AIR DATA SENSOR $398.00 PDC1200 VIDEO OVERLAY (PAL-D) $698.60 TRACKER GPS TELEMETRY SOFTWARE $198.60 PDC 3200 AUTOPILOT AND GROUNDSTATION: PRICE ON APPLICATION (PRICE DEPENDS ON CONFIGURATION). (ALL PRICES INCLUDE GST) Silvertone Electronics, PO Box 580, Riverwood 2210. Phone/Fax (02) 9533 3517. www.silvertone.com.au Need prototype PC boards? We have the solutions – we print electronics! Four-day turnaround, less if urgent; Artwork from your own positive or file; Through hole plating; Prompt postal service; 29 years technical experience; Inexpensive; Superb quality. Printed Electronics, 12A Aristoc Rd, Glen Waverley, Vic 3150. Phone: (03) 9545 3722; Fax: (03) 9545 3561 Call Mike Lynch and check us out! We are the best for low cost, small runs. G.S. & W.M. MILLAR TECHNICAL SUPPORT SOLUTIONS Electro-mechanical/Electronic repairs, rebuilds, maintenance, calibrations etc. Quality service at your site/s or in our workshop. PH: 0416 278-775 only ! $119 / $151 Full DIY Plug-In to TV / VCR 20 metre Cable, Plug Pack & Camera www.allthings.com.au DIGITAL OSCILLOSCOPE, USB, VHF Receiver; temperature/voltage measurement via phone kits. www.ar.com.au/~softmark PIC PROGRAMMING COURSE. Learn to write, debug and test code to a pro- Buy Direct From Manufacturer D.I.Y. PCB SUPPLIES pilots, and weather enthusiasts. Other models with barometric pressure, humidity, dew point, solar radiation, UV, leaf wetness, etc. Just phone, fax or write for our FREE catalogue and price list. Solar Flair/Ecowatch phone: (03) 5968 4863; fax: (03) 5968 5810, PO Box 18, Emerald, Vic., 3782. ACN 006 399 480. Pre Sensitized Copper Clad to make your own boards. Developer, Carbide Drills & Mills also manufacturer of Single & double sided boards. Comprehensive details at acetronics.com.au goto shop page ACETRONICS PCBs 5/32 Seton Rd Moorebank NSW 2170 02 9600 6832 Fax: 02 9600 6834 Mail: acetronics<at>acetronics.com.au Credit cards welcome Positions At Jaycar We are often looking for enthusiastic staff for positions in our retail stores and head office at Silverwater in Sydney. A genuine interest in electronics is a necessity. Phone 02 9741 8555 for current vacancies. fessional level. First chapter free. vladimir<at>u030.aone.net.au BULLET CCTV Cameras from $97 / $122 Mono / Colour www.allthings.com.au SPEAKER REPAIRS. New surrounds and voice-coils. New and re-conditioned continued next page September 2001  103 DON’T MISS THE ’BUS Advertising Index Acetronics..................................103 Altronics................................. 80-82 Allthings Sales & Services.102-104 Av-Comm Pty Ltd.......................103 Do you feel left behind by the latest advances in com­puter technology? Don’t miss the bus: get the ’bus! Includes articles on troubleshooting your PC, installing and setting up computer networks, hard disk drive upgrades, clean installing Windows 98, CPU upgrades, a basic introduction to Linux plus much more. Dick Smith Electronics........... 20-23 Price: $12.50 (incl. GST) Order now by using the handy order form in this issue or call (02) 9979 5644, 8.30-5.30 Mon-Fri with your credit card details. Jaycar ................................... 49-56 Dominion Electronics.................IFC Evatco..........................................87 Grantronics................................103 Harbuch Electronics....................48 Hy-Q International.......................35 Instant PCBs..............................103 Special subscription offer available only while stocks last. speakers, boxes and kits. (03) 5986 1128. DIY CCTV PAKS 4 Cameras & Switcher .................$354 4 COLOUR & Switcher ................$466 4 Cams & QUAD .........................$470 4 COLOUR & QUAD ....................$776 Time-Lapse 24 hr VCR only $599 with CCTV Systems! MORE at: www.allthings.com.au Fully Plug-In DIY Paks with Cables & Power Supplies * PC W98/W2000 Digital Motion/Sound detection & activat­ed Video/Audio Recording systems. Universal Programmer Clearance Sale: Superseded model Xeltek SuperPro/L, operates from PC printer port, programs 1000+ devices (40-pin max), including EPROMs and EEPROMs to 8MB, many flash devices, PLDs and MCUs (PICs, 8051 family, and many more). Also tests TTL/CMOS/RAM. Win95/98 and DOS s/w, free updates. See device list at www.xeltek-cn. com.$500 (incl. GST). Advanced Solutions P/L, Ph: (02) 9872 1981, dford1<at>bigpond.net.au Multiplexers CCTV Full-Screen Full-Resolution Recording FOUR TIMES MORE DATA than a Quad $599 / $919 Mono / Colour www.allthings.com.au RCS HAS MOVED to 41 Arlewis St, Chester Hill 2162 and is now open, with full production. Tel (02) 9738 0330; Fax 9738 0334. rcsradio<at>cia.com.au; www.cia.com.au/rcsradio 104  Silicon Chip VCR CCTV Controller use your home VCR to Record Events from $30 www.allthings.com.au PCBs MADE, ONE OR MANY. Low prices, hobbyists welcome. Sesame Elec­tronics (02) 9586 4771. sesame<at>internetezy.com.au; http:// members.tripod.com/~sesame_elec CCTV Equipment * BLEMISH FREE & LOW BLEMISH CCDs * up to 5 YEARS WARRANTY * OVERNIGHT DELIVERY * www.allthings.com.au VIDEO amplifiers, Stabilisers, TBCs, Converters, Mixers, etc. QUESTRONIX (02) 9477 3596. DOME CCTV Cameras from $53 / $77 Mono / Colour www.allthings.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 WANTED PERSON WITH EXPERIENCE/APTITUDE to fault find & repair PCBs – without diagrams. GENEROUS PKG NEG. Tel John<at>AER (03) 9482 4958 or 0415 305 470. JED Microprocessors.............35,59 Kalex..........................................101 Meterman....................................99 MicroZed Computers...................35 Oatley Electronics......................102 PolyKom......................................45 Printed Electronics.................... 103 Questronix...........................35, 103 RCS Radio.................................104 RF Probes...................................35 RobotOz......................................35 Rola Australia............................103 R.T.N............................................19 Silicon Chip Back Issues....... 96-97 Silicon Chip Bookshop........... 90-91 SC EFI Tech Special....................44 SC Electronics Testbench..........IBC SC Computer Omnibus...............95 Silicon Chip Subscriptions...........83 Silvertone Electronics................103 Smart Fastchargers...................101 Solar Flair/Ecowatch..................102 Technical Support Solutions......103 VAF Research...................35, OBC Wiltronics...................5,35,47,61,69 _____________________________ PC Boards Printed circuit boards for SILICON CHIP projects are made by: • RCS Radio Pty Ltd. Phone (02) 9738 0330. Fax (02) 9738 0334. www.siliconchip.com.au www.siliconchip.com.au September 2001  105