const int pirPin = 7;      // Pin connected to PIR sensor
const int ledPin = 12;     // Pin connected to LED

unsigned long motionDetectedTime = 0;
unsigned long ledOnTime = 0;
unsigned long responseTime = 0;

void setup() {
  pinMode(pirPin, INPUT);  // Set PIR pin as input
  pinMode(ledPin, OUTPUT); // Set LED pin as output
  Serial.begin(9600);      // Start serial communication
}

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

  if (pirValue == HIGH) {  // If motion is detected
    motionDetectedTime = micros();  // Record the time when motion is detected
    digitalWrite(ledPin, HIGH);    // Turn on the LED
    ledOnTime = micros();          // Record the time when LED turns on
    responseTime = ledOnTime - motionDetectedTime; // Calculate response time

    Serial.print("Response Time: ");
    Serial.print(responseTime);
    Serial.println(" microseconds");
  }

  delay(100);  // Small delay for stable reading
}