In this chapter, we learnt how to build a prototype for interfacing AC powered devices with the Arduino board as the controlling device. In the first part of the chapter, we learnt how to use a Relay device with the Arduino. In the second part we used the Relay device with an electric bulb. Eventually we used a sound detector to operate the Relay (indirectly the bulb) based on ambient sound.
In the next chapter we will learn how to use Infrared signals for wireless communications with the Arduino. We will look at transmitting as well as received data using Infrared transmitter and receiver components.