This was a fun project, but I ultimately went with an Ecobee thermostat and integrated it with HomeKit.
This is a project that I am working on in my spare time as a hobby. There will be bugs. The Arduino code is designed to work with a MQTT server application that I am also woking on (Central) and expects particular commands, however it could easily be adapted to your own setup. Feel free to use this code in any way as long as it does not go against the GNU GPLv3+ license. Maybe this will be of help to someone.
- Arduino program used on Adafruit Feather M0 WiFi
- Fritzing project includes all components on breadboard and schematic
- MQTT is the protocol used for communication
- Confirm whether changeover valve energized for heating or cooling
- Switch to smaller relays for space savings
- Custom board to house in plastic enclosure
- Switch to wired instead of wireless
Thermostat-for-Central Copright (C) 2017 John Hinson GNU GPL-3.0+ License