Fullscreen HTML5Med Res (??MB)HTML4

MARKET CENTRE Advertise your product or services here in Silicon Chip KIT ASSEMBLY & REPAIR FOR SALE PCB PRODUCTION 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, New Zealand, but service available Australia/NZ wide. Email dave<at>davethompson.co.nz LEDsales PCB MANUFACTURE: single to multilayer. Bare board tested. One-offs to any quantity. 48 hour service. Artwork design. Excellent prices. Check out our specials: www.ldelectronics.com.au KEITH RIPPON KIT ASSEMBLY & REPAIR: * Australia & New Zealand; * Small production runs. Phone Keith: 0409 662 794 keith.rippon<at>gmail.com LEDS, BRAND NAME AND GENERIC LEDs, filament LEDs, LED drivers, heatsinks, power supplies, kits and modules, components, breadboards, hardware, magnets. Please visit www. ledsales.com.au Silicon Chip Binders REAL VALUE AT $21.50 PLU S P&P PMD WAY offers (almost) everything for the electronics enthusiast – with full warranty, technical support and free delivery worldwide. Visit pmdway.com to get started. Order online from www.siliconchip.com.au/ Shop/4 or call (02) 9939 3295. 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 (02) 9939 3295. up, and if you do, then watch the SOA. There is not a lot of ‘room’ there for speakers that do surprising things, so if you can’t resist the temptation, then add an extra set of output devices. That is a little untidy, but it is only six more wires per amplifier. That buys you a lot of SOA headroom. ● We published a white noise generator in September 2018 (siliconchip. au/Article/11225). You could feed its output into an amplifier and then to speaker(s). You would probably want very directional speakers, perhaps using a parabolic reflector, to confound the camera without making a racket. White noise generator wanted Using a differential ADC for Reflow Oven My daughter unfortunately lives next door to the area snoop and gossip. She recently discovered that the neighbour’s security camera, which is allegedly aimed at the footpath, actually points over their deck and picks up what is said on the deck. It is probably illegal, but hard to prove, so I thought a white noise generator will probably solve the problem legally. Have you produced a suitable circuit? (J. A., Healesville, Vic) I am putting together all the parts to build the DIY Reflow Oven Controller project (April & May 2020 issues; siliconchip.au/Series/343). I have a question regarding the thermocouple amplifier section. I purchased the same module you used from eBay. It looks like it is a copy of an Adafruit design. Why does CON10 not indicate an input for the reference voltage? I would have thought it better to use a differential ADC measurement (direct or two siliconchip.com.au Australia's electronics magazine individual channel readings) so that the reference/offset voltage did not necessarily have to be known, as long as it provided a large enough positive temperature span. As you mentioned, 2.5V would be too large for a 3.3V system. What CON10 pin would you use/suggest? I will update the software to handle this. I am going to make my own special board to take the CON10 ribbon cable direct and have a separate twopin connector for the SSR connections. (M. V., Taree, NSW) ● The designer, Phil Prosser, responds: if I understand your intent, you are asking about using a second ADC channel to make the sensor temperature measurement independent of the temperature sensor’s DC offset. If your sensor output voltage range does not saturate the ADC across the full measurement range, you could certainly do that. You will need access to June 2026  103