Controlling relays is a central piece in any home automation system. With them, you can easily switch on and off any electrical device in your home, like lights. In this project, we are going to see how to wirelessly control a relay from your computer or your smartphone, to realize a wireless-controlled light switch for example. This project is the second part of a series showing you how to use Arduino & the CC3000 WiFi chip for home automation purposes. The first part was dedicated to how to read data wirelessly from a temperature & humidity sensor. Of course, you could use the same pieces of software to control a relay. However, in practice you just can’t use the same principles for this kind of application: it is just too slow. And we are going to see how to speed things up. As usual, the whole code for this project can be found inside our GitHub repository. Let’s dive in !