Subscribe to Arduino Academy and start learning today for FREE!

Home-Made Thermostat

By Avatar-X

If you’ve ever looked into automating the temperature control in your home, you will quickly have found out that it’s not a cheap prospect. The cheapest network-connected thermostat I could find was $450 US, and that’s just a start. So, I decided to build my own thermostat, using an Arduino and some other components.

My thermostat directly controls my HVAC unit, which has a standard four-wire interface. One wire is common, and there is one wire for each of Heat, Cool (A/C), and Fan. I’m using an LM35 to measure the temperature, three relays to connect the HVAC, a nice 20×2 LCD display for status, and some buttons and switches, all mounted into a project box. Since the Arduino has a built-in USB interface, I use that to provide status back to the computer, and allow the computer to issue commands.

Become the Maker you were born to be. Try Arduino Academy for FREE!

Notify of
Inline Feedbacks
View all comments


Would love your thoughts, please comment.x