const int ledPin = 13; // LED connected to digital pin 13
const int pirPin = 9;  // PIR sensor connected to digital pin 9

void setup() {
  pinMode(ledPin, OUTPUT); // Set LED pin as output
  pinMode(pirPin, INPUT);  // Set PIR pin as input
}

void loop() {
  int pirState = digitalRead(pirPin); // Read PIR sensor
  if (pirState == HIGH) { // If motion is detected
    digitalWrite(ledPin, HIGH); // Turn on LED
  } else {
    digitalWrite(ledPin, LOW); // Turn off LED
  }
}