I have a digital thermostat for the central heating and I want to control it via HA, probably through an ESP8266 or ESP32 with Esphome
Problem is, I have no idea where to start.
Let me attach some pictures about it
I can see there are connection points on the board like TX and RX, also there are 3,3V out. (last picture)
Any tips how to get started with this project? Better yet any similar one what I can use as an example.
https://vivonomicon.com/2018/11/22/bare-metal-msp430-programming-working-with-new-microcontrollers/
Esphome does not run on that processor.
Yes I’m aware of thaf. I want to controll it with an esp8266 like a wemos d1
You’ll need to analyse further.
Are you looking to replace the device? Who made it? Have you looked for an integration? How does it communicate with the world. When you analyse the tty what do you see? Is there a manual?
+1 on that ! I would first investigate way of communication with outside world of that device 
Perhaps an API or something similar !
I have to say the only good thing about the original device looks like the screen 
I do not want to replace it, only extend the functionality, with keeping the original.
Its sold by a company ‘Computherm’ COMPUTHERM T32 | Computherm - Digital, Wi-fi, mechanical thermostats
Most, but probably made somewhere in China.
I’m looking for an integration, that’s why I’m here.
As I wrote it has TX RX connection points, so I believe with Serial port I could communicate with it. Problem is I do not know how. With the UART module of ESP if I’m correct.
There is a manual, not helpful for this kind of modification.
Esphome will speak serial, but you will have to find out what the device’s serial protocol looks like.
If you search computherm on the forum you’ll find some info.