In this chapter, you will learn how to build a thermostat device using an Arduino. You will also learn how to use the temperature data to switch relays on and off. Relays are the main components that you can use for interaction between your Arduino and high-voltage electronic devices. The thermostat will also provide a web interface so that you can connect to it and check out the temperature.

Our example project will involve switching an electric fan on when the temperature rises above a set point of 25 degrees Celsius, and then switching it off when the temperature drops. We can use an ice cube and a hair dryer, or a similar device to stimulate the thermistor.

The code that controls the Arduino will also be ready to return data in a format that will be easy to insert into a database. We will create this database in Chapter 4, Temperature Storage – Setting Up a Database to Store Your Results.

Upon completion of the thermostat, you will have a device...