It reads the current temperature from a LM35 temperature sensor and actuates the valve to bring the wort to a set point. A neat addition to the build is a wireless radio.

Now you can build your own room temperature monitor using an Arduino board. The circuit is a combination of an Arduino UNO board, LM35 temperature sensor, ...

I used an LCD shield to display the current temperature and speed of the fan, but you can use the circuit without the LCD display. You also need to select the transistor by the type of fan that you ...