W1209 Temperature Control Thermostat Switch
You won't need a microcontroller for this one as this is a complete temperature controlled switch. It has a temperature sensor, as well as a relay that can control your electronics.
This module could control electricity-powered components with a voltage range of 14VDC and 125VAC with the current of 20A for both AC and DC voltages. 12V DC power-up this module. There is a 3-bit 7 segment display that indicates the temperature setting.
There are three buttons embedded into this module that has unique functions, with the first button that has the "SET" function. The second and the last button is for calibrating your thermostat with its function as "+" and "-" to increase and decrease the temperature you want to set.
You may use in powering up small fans as well as lighting up a bulb.