#define TRIG_PIN 9  // Pin for Trigger
#define ECHO_PIN 10 // Pin for Echo
#define LED_PIN 8   // Pin for LED

void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Set pin modes
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  // Get the distance from the ultrasonic sensor
  long duration = getUltrasonicDistance();
  float distance = duration * 0.034 / 2;  // Convert to centimeters

  // Display the distance in the Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // If distance is less than 10 cm, turn on the LED
  if (distance < 10) {
    digitalWrite(LED_PIN, HIGH);  // Turn LED on
  } else {
    digitalWrite(LED_PIN, LOW);   // Turn LED off
  }

  delay(1000);  // Wait for 1 second before measuring again
}

// Function to get the distance from the ultrasonic sensor
long getUltrasonicDistance() {
  // Clear the trigger pin
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  
  // Send a 10µs pulse to trigger the sensor
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  
  // Measure the duration for the echo pin to go HIGH
  long duration = pulseIn(ECHO_PIN, HIGH);
  
  return duration;
}