This is a simple heater controller that I wrote based off of the Tilt floating hydrometer, as well as Digital Loggers AC/DC Control Relay.
In order to build this, you need the gpiozero module.
I configure the Tilt to log to the device (the Pi, in this case). Then I use this script which watches that log file, parses out relevant fields, and then controls the AC/DC relay.
Note: I use GPIO port 26 right now. I'll likely make this a config entry at some point, but right now it's in the script.
I added a few safeties:
- If I can't parse the date or the temperature, I turn the heat off.
- If it's been too long (15 minutes) since I've seen an entry in the Tilt log file, I turn the heat off just in case the Tilt service bombed.
- I always default to turning the heat off. I don't know what the heat source is, so it might not be safe to leave the heat on.