// Motion-Activated LED Lighting (PIR)

// PIR sensor's output pin
const int pirPin = 2;    
// LED pin
const int ledPin = 13;   

// Initialize PIR sensor state
int pirState = LOW;      
// Previous PIR sensor state
int lastPirState = LOW;  


void setup() {
  // Read the signal from the PIR sensor to detect motion
  pinMode(pirPin, INPUT);
  
  // send a signal to the LED to turn it on or off
  pinMode(ledPin, OUTPUT);
  
  // Initializes the serial communication at a baud rate of 9600 bits per second.
  Serial.begin(9600);
}


void loop() {
  
  // Read PIR sensor value
  pirState = digitalRead(pirPin);  

  if (pirState == HIGH && lastPirState == LOW) {

    // PIR sensor detects motion
    digitalWrite(ledPin, HIGH);   // Turn on the LED
    Serial.println("Motion detected!");

  } else if (pirState == LOW && lastPirState == HIGH) {

    // PIR sensor no longer detects motion
    digitalWrite(ledPin, LOW);    // Turn off the LED
    Serial.println("Motion stopped.");
  }
  
  // Store current PIR state
  lastPirState = pirState;  
}