My parents growing their own organic food and they asked me to deal with winter temperatures problem in the storage room. It gets really cold here, in Ukraine. Some winters have even lower temperatures than -30°C (-22°F). So right now I designing a simple thermostat for keeping temperature at about 5-7 degrees C above zero. Plus right now I started to use my garage as a gym, so this thermostat would be handy there too.
It’s based around ATMEL AVR ATtiny2313 microcontroller, it will measure temperature using DS18B20 digital temperature sensor, and it has a 30A 240VAC relay to control heater.