Using an ESP8266 ESP-01 module and an Arduino Pro Mini 3.3V I wirelessly update all outputs from my thermostat to here for data analysis and because it's cool. This requires a voltage divided rectifier since thermostats run at least 24 VAC RMS.
Zestaw 3 x Hewalex KS2100 TLP ACR, sterownik G422-P08 i podgrzewacz ciepłej wody użytkowej 300l