Relay

Note

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Kit purchase

Looking for parts? Check out our all-in-one kits below — packed with components, beginner-friendly guides, and tons of fun.

Name	Includes Arduino board	PURCHASE LINK
Elite Explorer Kit	Arduino Uno R4 WiFi	BUY
3 in 1 Ultimate Starter Kit	Arduino Uno R4 Minima	BUY

Course Introduction

In this lesson, we will learn how to use the Relay with Arduino.

Note

If this is your first time working with an Arduino project, we recommend downloading and reviewing the basic materials first.

Required Components

In this project, we need the following components:

SN	COMPONENT INTRODUCTION	QUANTITY	PURCHASE LINK
1	Arduino UNO R4 Minima	1	BUY
2	USB Type-C cable	1
3	Breadboard	1	BUY
4	Wires	Several	BUY
5	Relay	1

Wiring

Common Connections:

Relay
- S: Connect to 6 on the Arduino.
- GND: Connect to GND on the Arduino.
- VCC: Connect to 5V on the Arduino.
- NO: Connect to 5V on the Arduino.
Traffic light LED
- R: Connect to COM on the relay.
- GND: Connect to GND on the Arduino.

Writing the Code

Note

You can copy this code into Arduino IDE.
Don’t forget to select the board(Arduino UNO R4 Minima) and the correct port before clicking the Upload button.

/*
  This code controls a one channel relay module using an Arduino Uno.
  The relay is turned on and off in a loop, with a delay of 3 seconds
  between each state change.

  Board: Arduino Uno R3 (or R4)
  Component: One Channel Relay Module
*/

// Define the relay pin as pin 6
const int relayPin = 6;

void setup() {
  // Set relayPin as an output pin
  pinMode(relayPin, OUTPUT);
}

void loop() {
  // Turn off the relay by setting the pin LOW
  digitalWrite(relayPin, LOW);
  delay(1000);

  // Turn on the relay by setting the pin HIGH
  digitalWrite(relayPin, HIGH);
  delay(1000);
}