How to Power Light Bulbs Using an Arduino With a Relay Module

Controlling tiny LEDs with an Arduino can be a fun project to kick off your journey learning DIY electronics. But do you know what’s even more fun? Powering light bulbs with a custom-built Arduino project: large, high-power, room-enlightening light bulbs!

However, the Arduino can’t emit more than 5V from any of its pins, let alone enough to power a light bulb that needs 30 to 40 times the voltage for an LED. That’s why you’re supposed to use a relay module instead. Here’s how to do that with your Arduino.

What Is a Relay Module?

A relay module (or relay, for short) is an electromagnetic switch that lets you control something connected to the mains electricity with a low-power microcontroller, like an Arduino Uno or ESP32.

Relays have two kinds of terminals: one that’s high-voltage tolerant (think 220V) and another that only accepts low-voltage output.

When you pass an electric current through the low-voltage pins, you’re powering an electromagnet that pulls a “switch,” turning it either on or off, depending on the configuration you’re using.

An SPDT relay always has six pins: typically with three male headers for connection to the Arduino and three screw terminal pins to connect to mains electricity.

Read More: How to Power Light Bulbs Using an Arduino With a Relay Module – Make Tech Easier