This is the newest node in my little PiNet. It's also the least finished of the group. You might think it's ugly, and you'd be mostly right. I have no intention of caring how it looks, only how it works.
I used an early Pi B+ and a Elegoo 8-relay board along with a DS18B20 W1 temp probe and a BME280 for sensors. The BME280 is the primary sensor, the W1 probe is zip tied to the front grill of the window unit and can act as a comparison temperature source.
I learned it's a lot more difficult writing software to control cooling and heating of a room than I thought. Honestly, I'm not sure I've done a very good job of it, but the window unit works, and 'thermostat.py' does it's job.
I am planning to make substantive improvements, and consider this to be in the 'alpha' stages of development at this time (Dec 2020).
I have a separate relay-controlled electric space heater that I use to heat the shop. ShopPi's relay board is hooked up in parallel with a standard cheap analog thermostat. The analog thermostat now acts as a high temp safety. It's set for about 80F, so if ShopPi fails to turn the space heater off, the bimetal thermo will turn it off. It's a good backup to have.