Arduino Thermostat Projects

Control heating and cooling in your home with these Arduino projects.

woman adjusting digital thermostat

 Peter Dazeley/The Image Bank/Getty Images

Home heating, ventilation, and air conditioning (HVAC) systems are notoriously inaccessible to most users. For decades they've been the strict domain of trained specialists and technicians.

Game-changing technologies like the Nest learning thermostat have added some much needed transparency to the space. Enthusiasts can now design and develop their own hardware for controlling the temperature in their home. The go-to hardware for such a project is the Arduino controller.

What Is Arduino?

Arduino is an open-source hardware and software system that consists of an easily programmable circuit board, known as a microcontroller. The system also includes software to be run on a computer. Arduino allows users to create devices that can sense and interact with their environment both physically and digitally.

New possibilities for the casual tinkerer

These projects should provide an idea of how Arduino can be a great entry point to what was once an inaccessible part of home control. Arduino is a great learning tool and an even better gateway to new programming projects.

If you're interested in other project for Arduino, look into ideas like Arduino motion sensor projects or Arduino thermostats projects.

A Simple DIY Thermostat Project

Thermostat
Thermostat.

 Peter Dazeley/The Image Bank/Getty Images

This do-it-yourself thermostat project is one of the simpler Arduino-based thermostat solutions and is ideal for a beginner. It uses a Dallas DS18B20 one-wire temperature sensor and a simple LED-and-LCD combo to indicate temperature and thermostat status. A relay shield provides the outputs that interface with the home HVAC system. If you're not looking to add any network features or sophisticated functionality to your Arduino thermostat, then this project provides the basics for any thermostat project.

A Network-Enabled Thermostat

Close up of male hands holding an Arduino microcontroller board
Ernesto r. Ageitos / Getty Images

For a more complex look at the possibilities of an Arduino-based thermostat, this project has a number of versions of a network-linked thermostat for interfacing with HVAC systems. Over time, this project has become increasingly complex, with additional features like a complex multicolor display with a temperature and humidity sensor.

A Fridge Controller

Fridge organization.
The Spruce / Diana Rattray

Home HVAC systems are not the only systems that require a thermostat. Refrigerators are also typically controlled using a thermostat. If your refrigerator is causing problems due to a faulty thermostat, this Arduino refrigerator project may offer a solution. The project uses the same Dallas temperature sensor seen in the Simple DIY Thermostat Project listed above, providing control for the compressor on the back of the refrigerator. Later updates provide the addition of an ethernet shield for logging the temperature and compressor state.

A Web-Accessible Thermometer

Thermometer
Thermometer. Michael Phillips/E+/Getty Images

Perhaps you aren't looking to replace an entire thermostat system with a homebrew Arduino solution, but you would like to create a thermometer that's accessible on the web. This might be useful for a number of different applications, both around the home and potentially to monitor work environments like server rooms. The project creates a web-accessible thermometer, and the accompanying code uses a simple website and mobile app to create a messaging interface between the user and the thermometer device.