OT : Why build when you can buy ?

@premelec: Fry's was THE place for years, started as a regular supermarket and added electronic parts. They carried a lot of pro level components and tools etc, and you could do your grocery shopping at the same time They sold the grocery biz and morphed into a chain of fancy computer/consumer electronics/appliances stores with a limited range of components (but still a lot better than nothing if you were close by).

The DSE story kind of reminds me about Radio Shack.

I remember when I was a teenager, Radio Shack was THE place to visit for all of your electronic needs. From transistors and passive components, to test equipment, speakers, and everything in between.

premelec said:

A small length of dowel or aluminum with a cup in it's end and glue would do the job for you.... or a trained cricket... ;-0

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Luckily this is only controlling a home made beer cooler, that I built years ago, using a couple of big heatsinks, a fan, plus the biggest (at that time) Peltier heat pump module I could find. The control problem is that if you turn the Peltier and external fan off with a thermostat, then the heat very quickly flow back into the well-insulated and sealed box via the Peltier device itself and its associated heat sinks. This means that I never bothered to fit a thermostat, and just run it flat out all the time, but it draws several amps at 12V, which is fine when the car's running, not so good when parked up'

I added one of these thermostats to switch the external fan off and crudely switch most of the power off to the Peltier module. I have a resistor across the thermostat relay to allow a low current through the Peltier module, just enough to limit the heat flowing inwards. It works fine, and luckily I don't need to get at the buttons now the thing is set up, in fact it's buried inside the case, so not easy to get at.

I have a few other simple temperature control projects where one of these would be fine, but I'd need to get at the buttons. I think the easy way out might be to just solder extension wires to the existing buttons and bring them out to panel mounted buttons, leaving just a window for the display.

I could mess around with converting a serial LCD display to do this job, using some custom code and the spare pins on the AXE133 budget LCD. There are effectively C.0, C1. C.2 and C.5 available as spare pins (if you're not using the module as a serial display), plus the serial input and output programming pins at a pinch, which is enough for a couple of buttons, a relay drive output and a DS18B20. Quite a bit of faffing around compared to just buying one of these dirt cheap thermostat modules and hacking it to get at the push buttons..................

Jeremy Harris said:

I never bothered to fit a thermostat, and just run it flat out all the time, but it draws several amps at 12V, which is fine when the car's running, not so good when parked up'

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Well, as long as the beer stays cold while we're out drinking and driving...

JK kids, don't try this at home, or on the road... or maybe I'll just shut up now.