⚡ Button Controlled Relay – Arduino UNO

This project demonstrates how to control an electrical relay module using a push button and an Arduino UNO.
When the button is pressed, the relay activates; when released, it deactivates — a foundational project for learning home automation and device control.

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🧠 Overview

A relay is an electrically operated switch used to control high-power devices (like lights, fans, or motors) with a low-power signal from a microcontroller.
This project introduces how to trigger the relay module through a button input signal.

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⚙️ Hardware Requirements

• Arduino UNO
• 5V Relay Module
• Push Button
• 10kΩ pull-down resistor
• Jumper wires
• Breadboard

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🔌 Circuit Connections

Component	Arduino Pin	Description
Relay Module IN	D8	Relay control signal
Button	D7	Input signal from button
Relay VCC	5V	Power supply
Relay GND	GND	Common ground
Button GND	GND	Common ground

🧩 Logic:

• Button Pressed (HIGH): Relay turns ON
• Button Released (LOW): Relay turns OFF

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💻 Arduino Code

const int button = 7;
const int relay = 8;

void setup()
{
  pinMode(relay, OUTPUT);
  pinMode(button, INPUT); 
}

unsigned char button_state;

void loop()
{
  button_state = digitalRead(button);

  if(button_state == HIGH)
  {
    digitalWrite(relay, HIGH);
  }
  else
  {
    digitalWrite(relay, LOW);
  }
}

🚀 How It Works When the button is pressed, the Arduino reads HIGH at pin D7.

This signal activates the relay module through pin D8.

The relay’s switch closes, allowing current to flow to the connected load.

Releasing the button sends a LOW signal, turning the relay OFF.

⚠️ Safety Note If you’re using the relay to switch AC appliances, always handle wiring with care. Make sure to isolate low-voltage (Arduino side) and high-voltage (load side) properly.

🧰 Software Tools Arduino IDE (v2.0 or later)

Arduino UNO Drivers

📸 Output Behavior Button State Relay State Output Device Pressed (HIGH) ON Activated Released (LOW) OFF Deactivated

💡 Applications Smart Home Automation

Load Control Systems

Motor Control

IoT Energy Management