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MARKET CENTRE Cash in your surplus gear. Advertise it here in SILICON CHIP FOR SALE LEDs, BRAND NAME and generic LEDs. Heatsinks, fans, LED drivers, power supplies, LED ribbon, kits, components, hardware, EL wire. www.ledsales.com.au tronixlabs.com.au – Australia’s best value for supported hobbyist electronics from Adafruit, SparkFun, Arduino, Freetronics, Raspberry Pi – along with kits, components and much more – with same-day shipping. Where do you get those HARD-TO-GET PARTS? Where possible, the SILICON CHIP On-Line Shop stocks hard-to-get project parts, along with PCBs, programmed micros, panels and all the other bits and pieces to enable you to complete your SILICON CHIP project. SILICON CHIP On-Line SHOP www.siliconchip.com.au/shop PCB PRODUCTION PCB MANUFACTURE: single to multi­ layer. Bare board tested. One-offs to any quantity. 48 hour service. Artwork design. Excellent prices. Check out our specials: www.ldelectronics.com.au KIT ASSEMBLY & REPAIR KEITH RIPPON KIT ASSEMBLY & REPAIR: * Australia & New Zealand; * Small production runs. Phone Keith: 0409 662 794 keith.rippon<at>gmail.com DAVE THOMPSON (the Serviceman from SILICON CHIP) is available to help you with kit assembly, project troubleshooting, general electronics and custom design work. No job too small. Based in Christchurch, NZ but service available Australia/NZ wide. Email dave<at>davethompson.co.nz VINTAGE RADIO REPAIRS: electrical mechanical fitter with 36 years ex­ perience and extensive knowledge of valve and transistor radios. Professional and reliable repairs. All workmanship guaranteed. $17 inspection fee plus charges for parts and labour as required. Labour fees $38 p/h. Pensioner discounts available on application. Contact Alan, VK2FALW on 0425 122 415 or email bigalradioshack<at>gmail. com NEED A NEW PCB DESIGNED? Or need to update an old board? We do PCB layouts from circuits, drawings, photocopies or sample boards. Contact Steve at sgobrien8<at>gmail.com or phone 0401 157 285. Get a new PCB and keep production going! ADVERTISING IN MARKET CENTRE Classified Ad Rates: $32.00 for up to 20 words (punctuation not charged) plus $1.20 for each additional word. Display ads in Market Centre (minimum 2cm deep, maximum 10cm deep): $82.50 per column centimetre per insertion. All prices include GST. Closing date: 5 weeks prior to month of sale. To book, email the text to silicon<at>siliconchip.com.au and include your name, address & credit card details, or phone Glyn (02) 9939 3295 or 0431 792 293. I believe that it’s because I use LED interior lights in my car. The circuit draws its power from being connected in series with the light and the LED light drops the supply voltage for the delay unit to around 5V, rather than the 12V an incandescent globe would supply (and what the circuit requires). Is there a simple modification you could suggest to adapt this circuit for use with LED lights? I believe that I could have the circuit drive a relay which in turn would drive the LED lights. That would provide a delay but I’d miss out on the fading effect, which siliconchip.com.au would be nice to have. I’m also not sure what effect the fading would have on switching the relay. Do you have any better ideas for me, or am I resigned to buying a more up to date module that supports LEDs? • We published a revised Courtesy Light Delay (October 2014; siliconchip.com.au/Article/8031) to solve this very problem. You could build that unit instead, as it is designed to give a smooth dimming of LED lamps. The PCB and programmed microcontroller are available from the Silicon Australia’s electronics magazine Chip Online Shop at siliconchip.com. au/Shop/?article=8031 If you prefer the June 2004 version, you will need a filament lamp as a lamp load. You can still use the LED lighting in the car but you will need to connect a filament (ie, incandescent) lamp in parallel to provide a low resistance supply to the circuit. While this should work, the LED dimming will not be as effective compared to the revised October 2014 version. We don’t suggest you use a relay as the coil resistance would be too high for the circuit to work properly. SC October 2018  111