PIR Motion Detection System using Arduino UNO

📌 Overview:

This project demonstrates a simple Motion Detection System using an Arduino UNO, PIR Sensor, and LED. The PIR sensor detects movement and sends a HIGH signal to the Arduino. Based on this signal, the Arduino turns ON the LED and displays the motion status on the Serial Monitor.

This project is useful for learning: Arduino programming PIR sensor interfacing Embedded systems basics Home automation concepts

🛠 Components Required:

Arduino UNO PIR Sensor LED 220Ω Resistor Breadboard Jumper Wires USB Cable

🔌 Circuit Connections

PIR Sensor to Arduino:

PIR Sensor Arduino UNO VCC 5V GND GND OUT D2

LED Connections: LED Pin Arduino Connection Positive (+) D13 through 220Ω resistor Negative (-) GND

⚙️ Working Principle:

The PIR sensor monitors infrared radiation. When motion is detected, the PIR output becomes HIGH. Arduino reads the HIGH signal from pin D2. The LED connected to pin D13 turns ON. Serial Monitor displays: “Motion Detected!” When no motion is detected: LED turns OFF Serial Monitor displays “No Motion”

💻 Arduino Code

int pirPin = 2;
int ledPin = 13;

void setup() {

  pinMode(pirPin, INPUT);
  pinMode(ledPin, OUTPUT);

  Serial.begin(9600);

  Serial.println("PIR Motion Sensor Started");
}

void loop() {

  int motion = digitalRead(pirPin);

  if (motion == HIGH) {

    digitalWrite(ledPin, HIGH);

    Serial.println("Motion Detected!");

  }
  else {

    digitalWrite(ledPin, LOW);

    Serial.println("No Motion");

  }

  delay(200);
}

📊 Output:

Motion Status LED Serial Monitor.

Motion Detected ON Motion Detected!

No Motion OFF No Motion.

✅ Conclusion

This project successfully demonstrates a basic motion detection and alert system using Arduino UNO and a PIR sensor. It helps beginners understand sensor interfacing, digital input/output operations, and embedded system applications in real-world automation systems.