Replacing a standard thermostat (SIEMENS-RAA30 16GR) with a self made, arduino-based, big LCD screen is a fun project.
DISCLAIMER: Mains power is used in both controlling the furnace and for arduino power so please do not proceed if you are not comfortable working with mains power. I assume no responsibility if you hurt yourself or others while making this project.
The main features of the thermostat are:
- Big LCD (20x4 chars, blue background, white chars
- Controlled by a single knob (a pushable encoder)
- Leds for thermostat closed and furnace burning.
- Suspend mode (for night).
- Extensible (will add summer mode for boiler and wifi/EasyIOT connectivity)
Code available on github for anyone to download/experiment/fork here: https://github.com/akorbeti/thermostat/tree/master