The open source project allows you to control DC appliances based on the temperature of two thermistor inputs. It uses AVR ATmega48 as main processor. The controller has both green and white LEDs to indicate status. The project output is connected to N-Channel MOSFET, AOD444, for switching with current up to 4A. For higher current you can use relay.
To get you started, Jeffrey Nichols from ubertechnics has included a temperature comparison program for an automatic heat exchanger.
This free embedded project also found using:
- Atmel AVR HACK – Temperature Controller using Microcontroller AVR