We make a brief introduction to the relay module and build a simple project example with the Arduino. The example we’ll build shows how to control a relay module with an Arduino and a PIR motion sensor. By the end of this tutorial, you should be able to

The blue-colored box is the relay and we call the entire piece a relay module. They come in different shapes and forms.It is possible to get the relay separately however I recommend to always buy the relay module instead because it will take a lot of work

Putting the Diode between the Relay and Arduino, will protect us from power surges when the Relay switches since the Diode only allows current to flow one way. For more information about the Relay module connections and IR Motion sensor jumper settings, p