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Using HC-SR501 Motion Sensor with relay and Arduino code Robojax.com

Using HC-SR501 Motion Sensor with relay and Arduino code

This video shows you how to control a relay when motion is detected. You can turn an alarm or AC bulb or any other load by detecting motion using Arduino and HC-SR501 motion sensor.

Arduino Source code for HC-SR501 Motion sensor to control AC bulb or load


 /*
 * This Arduino code uses HS-SR501 motion sensor and a relay
 * and switches an alarm or a device using relay when motion is detected
 * the device can be an alarm or light or any other device
 *

 * Written by Ahmad Shamshiri on August 05, 2018 at 12:36 for Robojax.com
 * in Ajax, Ontario, Canada
 * watch video instruction of this code: https://youtu.be/QQ7iDagQnQM
 * This code has been downloaded from Robojax.com

 */

const int SENSOR_PIN = 2;// the Arduino pin connected to output (middle) wire of sensor
const int RELAY_PIN = 4;// the Arduino pin which is connected to control relay

void setup() {
  Serial.begin(9600);// setup Serial Monitor to display information
   Serial.println("Robojax Arduino Tutorial");
   Serial.println("HC-SR501 sensor with relay");
  pinMode(SENSOR_PIN, INPUT);// Define SENSOR_PIN as Input from sensor
  pinMode(RELAY_PIN, OUTPUT);// Define RELAY_PIN as OUTPUT for relay
}

void loop() {
  // Robojax.com HC-SR501 motion sensor tutorial Aug 05, 2018
  int motion =digitalRead(SENSOR_PIN);// read the sensor pin and stores it in "motion" variable
 
  // if motion is detected
  if(motion){
    Serial.println("Motion detected");
    digitalWrite(RELAY_PIN, LOW);// Turn the relay ON
  }else{
     Serial.println("===nothing moves");
     digitalWrite(RELAY_PIN,HIGH);// Turn the relay OFF
  }
  delay(500);
  // Robojax.com HC-SR501 motion sensor tutorial Aug 05, 2018
}