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SILICON CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Editor Peter Smith Technical Staff John Clarke, B.E.(Elec.) Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Reader Services Ann Jenkinson Advertising Enquiries Glyn Smith Phone (02) 9939 3295 Mobile 0431 792 293 glyn<at>siliconchip.com.au Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Kevin Poulter Mike Sheriff, B.Sc, VK2YFK Stan Swan SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490 All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Hannanprint, Noble Park, Victoria. Distribution: Network Distribution Company. Subscription rates: $89.50 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial office: Unit 1, 234 Harbord Rd, Brookvale, NSW 2100. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9939 3295. Fax (02) 9939 2648. E-mail: silicon<at>siliconchip.com.au ISSN 1030-2662 * Recommended and maximum price only. 2  Silicon Chip Publisher’s Letter Cheap battery drills are very wasteful For quite a few years now, we have been concerned about the waste of resources concerned with electrical and electronic equipment. It is bad enough that most electronic equipment is now so cheap that it is not worth repairing when it finally does fail. At least if it gives a reasonably long service life, you don’t mind so much if it then has to be replaced with a new one rather than being repaired. But I still regard the huge amount of electronics going to the tip each year, all for the want of a simple (albeit uneconomical) repair, as a huge waste. Cars and large appliances such as fridges and washing machines get discarded too but at least most of their metal content does get recycled. But cheap electrical and electronic appliances don’t last very long and then they end up on the tip. Even worse is the situation with cheap battery-powered electric drills. Because their battery life is so short, there must be tens of thousands of these drills being discarded every year. They work for a short time, then the battery ceases holding a charge and out into the bin they go, to be replaced by another drill. In fact, the drill itself is fine but the battery is ruined and you can not get a replacement. This is an unconscionable waste of resources. So in conjunction with Jaycar Electronics, we have done something about it. First, there is the article beginning on 24 about repacking the cells in your drill’s battery pack. This is not a cheap exercise and will typically cost a lot more than the price of a new drill – but at least you are starting afresh with good cells. But given that the chargers for these drills are so rudimentary, that is only half the task. To ensure that your new battery pack has a reasonable life, you need to incorporate a specified thermistor in the battery pack and then build the Drill Charger Controller described in the article beginning on page 32. With over-temperature and time-out functions, this will prevent the cells from being over-charged and they should last many times longer than in normal drills. In fact, even if the battery pack in your present drill is still OK, I would strongly recommend that you modify it along the lines described and build the Charger Controller. Or if you go out and buy a new battery drill, don’t wait for the battery to deteriorate – modify it straight away to ensure a reasonable life. After all, there is no point in spending $30 or so on a new drill if you know that it is going to have a very short life. The really irresponsible parties in this whole affair are the manufacturers who are churning out this short-lived rubbish and the importers and retailers who ultimately sell it to the public. It is in their interests to keep this wasteful cycle going, isn’t it? For the want of a better charger which would only add a few dollars to the price, the retailers are probably selling many more drills than they otherwise would. Unfortunately, there is a great deal of electronics gear for which there are no simple refinements but there is still a curb that you and I can apply. Every time you are confronted by some cheap (or not so cheap) electronic gadget, ask yourself, “Do I really need this?” The chances are that you don’t or you can wait until you have saved enough for a better-made unit. If enough Australians took this approach, we could substantially cut our import bill and ultimately, substantially reduce the torrent of discarded gear going to the tip. Leo Simpson siliconchip.com.au