Arduino Home Thermostat and Environment Interface I use this sketch in the Arduino UNO, Mega2560, Leonardo and Wemo XI (TTGO XI) as my thermostat, and you can easily modify it for humidistat as well.

There are hundreds of homemade thermostats with various MCU and sensors. Some are very simple, others are very sophisticated. However I decided to build my own thermostat especially for a solar panel ...