Controlling a 5V Relay Using Arduino to cotrol AC or DC load like bulb or motor

Controlling a 5V Relay Using Arduino to cotrol AC or DC load like bulb or motor

This tutorial demonstrates how to use a 5V relay module with Arduino to control high-voltage devices such as lights, fans, or other appliances. The relay used in this lesson is high-trigger, meaning it activates when the signal pin receives a high-level voltage (5V).

Relay modules are essential in home automation and industrial control systems, allowing you to safely interface microcontrollers with AC-powered devices.

The Arduino code and wiring diagram are available below this article.

What is a High-Trigger Relay?

A relay is an electromechanical switch controlled electrically. The high-trigger version activates when the input signal pin is brought HIGH (typically 5V). It contains:

• An electromagnetic coil for switching

• A normally open (NO) and normally closed (NC) contact

  

  

• Signal, VCC, and GND pins

This module allows Arduino to control devices that operate at a higher voltage than the board can handle directly.

Wiring the Relay Module

To safely use the relay with Arduino, wire it as follows:

• VCC (middle pin) -5V on Arduino

• GND -GND on Arduino

• IN (Signal pin) -Digital Pin 2 on Arduino

• Relay Output terminals -Connect one of the terminals in series with a light bulb, fan, or any other AC/DC load.

 Code Overview

Here’s the basic Arduino code used in this lesson:

cppCopyEditvoid setup() {
  pinMode(2, OUTPUT);     // Set pin 2 as output
}

void loop() {
  digitalWrite(2, HIGH);  // Turn relay ON
  delay(1000);            // Wait 1 second
  digitalWrite(2, LOW);   // Turn relay OFF
  delay(1000);            // Wait 1 second
}

• The relay is turned ON when digital pin 2 is set to HIGH.

• The relay is turned OFF when pin 2 is set to LOW.

• The cycle repeats every 1 second.

This setup is commonly used to automate home lighting or power control based on sensors or time schedules.

Chapters From the Video

• 00:00 – Relay Explained

• 03:33 – Wiring Explained

• 04:42 – Code Explained

• 06:10 – Demonstration

Hình ảnh

Relay wiring when load is OFF

Relay wiring when load is ON

5V relay module

5V HIGH-level trigger relay module

5V HIGH-level trigger relay module

5V HIGH-level trigger relay module - back

Arduino wiring for AC bulb with HIGH-level trigger relay

Relay wiring when load is OFF

Relay wiring when load is ON

5V relay module

5V HIGH-level trigger relay module

5V HIGH-level trigger relay module

5V HIGH-level trigger relay module - back

Arduino wiring for AC bulb with HIGH-level trigger relay

/*
* This is the Arduino code for Dual Channel 5V Relay
* to control turning ON or OFF AC or DC loads
* Watch the video https://youtu.be/58XWVDnB7Ss
*
* Written by Ahmad Nejrabi for Robojax Video
* Date: December 26, 2017, in Ajax, Ontario, Canada
* Permission granted to share this code given that this
* note is kept with the code.
* Disclaimer: this code is "AS IS" and for educational purposes only.
*
*/

void setup() {
  pinMode(7, OUTPUT);// connected to S terminal of Relay

}

void loop() {

  digitalWrite(7,HIGH);// turn relay ON
  delay(3000);// keep it ON for 3 seconds

  digitalWrite(7, LOW);// turn relay OFF
 delay(5000);// keep it OFF for 5 seconds

}