Arduino with Pir Motion Sensor | Control Your Room Light by Motion Detection

Overview

In this tutorial, we will learn how to make automatic room light control by human motion detector using a PIR (Passive Infrared Sensor) sensor with Arduino. 

You can watch the following video below:-

Components Required

The required components list for this project given below:-

• Arduino Uno
• Pir Motion Sensor 
• 5V Relay Module
• AC Bulb
• Breadboard
• Some Jumper Wire

Pir Motion Sensor Pinout

The pinout of the Pir motion sensor has been given below:- 

Fig: Pir Motion Pin Configuration

Circuit Schematic

The circuit diagram of the Pir motion sensor interfacing with Arduino has been given below:- 

Fig: Pir Motion Sensor Interfacing with Arduino

Circuit Description

Source Code

The source code is given below:-

 boolean sensingLow = true;  
 boolean takeSensingTime;   
    
 int pirPin = 7;  //the digital pin connected to the PIR sensor's output  
 int ledPin = 8;   
   
 void setup(){  
  Serial.begin(9600);  
  pinMode(pirPin, INPUT);  
  pinMode(ledPin, OUTPUT);  
  digitalWrite(pirPin, LOW);  
    
  Serial.print("calibrating sensor ");  
   for(int i = 0; i < 10; i++){  
    Serial.print(".");  
    delay(1000);  
    }  
   Serial.println(" done");  
   Serial.println("SENSOR ACTIVE");  
   delay(50);  
  }  
   
 void loop(){  
    
    if(digitalRead(pirPin) == HIGH){  
     digitalWrite(ledPin, LOW);  //the led visualizes the sensors output pin state  
     if(sensingLow){   
     sensingLow = false;        
      }      
      takeSensingTime = true;  
     }  
    
    if(digitalRead(pirPin) == LOW){     
     digitalWrite(ledPin, HIGH); //the led visualizes the sensors output pin state  
     if(takeSensingTime){  
     takeSensingTime = false;    //make sure this is only done at the start of a LOW phase  
     }  
     }  
  }