Project 4

PIR Motion Sensor - Arduino Uno

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Project Description

A motion detector is an electronic device that senses movement within a specific area and triggers a response such as turning on a light, sounding an alarm, or sending a notification. It works by detecting changes in infrared radiation (PIR), microwave signals. Motion detectors are widely used in security systems, automatic lighting, smart home devices, and energy-saving applications because they operate automatically and require very little power.

The sensitivity of the PIR sensor can be adjusted with a small screwdriver using the potetiometers beneath sensor.
Components
  • Arduino Uno
  • PIR Sensor
  • Jumper wires
  • Breadboard
  • LED 
  • Resistor (220 Ohm) - [Red-Red-Brown-Gold]
Code 

int pirPin = 8;     // PIR sensor output pin
int ledPin = 7;    // LED pin

void setup() {
  pinMode(pirPin, INPUT);    // PIR sensor as input
  pinMode(ledPin, OUTPUT);   // LED as output
  Serial.begin(9600);
  Serial.println("PIR Sensor Active...");
}

void loop() {
  int motion = digitalRead(pirPin);  // Read PIR output

  if (motion == HIGH) {
    digitalWrite(ledPin, HIGH);      // Turn LED ON
    Serial.println("Motion Detected");
  } else {
    digitalWrite(ledPin, LOW);       // Turn LED OFF
    Serial.println("No Motion");
  }

  delay(100); // Small delay to avoid rapid toggling
}

Taking things further
  • A relay can be added to control lights and make an energy saving light and automatic for corridors, bathrooms and outdoor areas
  • Add a buzzer to make a motion sensitive security system.
  • A camera module can be triggered to begin recording