Introduction to PIR Sensor:

A PIR sensor is a device that can detect the presence of humans or animals by measuring the infrared radiation emitted by their bodies. It is commonly used in security systems, motion-activated lighting, and other applications that require motion detection.

Working Principle:

A PIR sensor detects changes in infrared radiation within its field of view. The sensor consists of two halves, each containing a pyroelectric sensor. When an object emits infrared radiation, the sensor detects the difference in heat between the two halves, triggering an output signal.

Specification of PIR Sensor:

• Detection range: up to 7 meters
• Detection angle: 110 degrees
• Operating voltage: DC 4.5V – 12V DC
• Output signal: 3.3V digital output
• Delay time: adjustable from 0.3 seconds to 5 minutes
• Operating temperature: -15°C to +70°C
• Sensitivity: Adjustable
•  

Adjusting PIR Sensor Sensitivity:

Some PIR sensors have a sensitivity adjustment potentiometer. By adjusting this potentiometer, you can control the detection range and sensitivity of the sensor.

Components Required

1. Arduino UNO
2. PIR Sensor
3. Power supply 
4. Connecting wires

Hardware Connections:

To connect the PIR sensor to an Arduino board, follow these steps:

1. VCC pin–5V pin of the Arduino board.
2.  GND pin–GND pin of the Arduino board.

  3. OUT pin–Connect it to digital pin 9 of the Arduino.

Circuit Connection:

CODE:

int pirPin = 9;     //projectkitsandparts.com/ develop by Surabhi.N.Bhivsenkar

void setup() {

  Serial.begin(9600);

  pinMode(pirPin, INPUT);

}

void loop() {

  int motion = digitalRead(pirPin);

  if (motion == HIGH) {

    Serial.println(“Motion detected!”);

  } else {

    Serial.println(“No motion detected.”);

  }

  delay(1000);

}

Code Explanation:

1  In the `setup()` function, we initialize the serial communication at a baud rate of 9600 and set the PIR pin as an input.

2   In the `loop()` function, we read the state of the PIR sensor using `digitalRead(pirPin)`. If motion is detected (the PIR sensor outputs a HIGH signal), it prints “Motion detected!” to the serial monitor. Otherwise, it prints “No motion detected.”

3  We introduce a delay of 1 second between readings using `delay(1000)`.

OUTPUT