My dad needed an automatic control of the shunt on his water heater. The old system had broke, and a system for measuring water temperature and controlling the shunt was developed. The system uses a DS1820 to measure temperature. The data is transmitted over the 433MHz bandto the main board. Desired temperature is selectable, and some debug prints is seen on the LCD screen.

The system is accurate to 0.5 degrees centigrade and has been working fine for over a year.

 Early debug version.