Comment by hattmall
14 hours ago
If anyone is looking for something similar it's worth looking into A somewhat less complex solution that preserves all functionality. Use the IR receiver plus a broadlink IR Hub. You can meet all the goals here, run it all locally the only downside is no 2 way communication. So if you do change the thermostat via the wall it won't be reflected in your app.
This project isn't very complicated, doesn't require extra power source, and doesn't beep every time you change the settings.
You can add a camera pointing to the display and analyze the image. You would have a perfect galvanic separation for reasons.