#define trigger_pin 2
#define echo_pin 3
#define led_pin 12

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

  // Set pin modes
  pinMode(trigger_pin, OUTPUT);
  pinMode(echo_pin, INPUT);
  pinMode(led_pin, OUTPUT);
}

void loop() {
  // Send a short pulse to trigger the sensor
  digitalWrite(trigger_pin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigger_pin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigger_pin, LOW);

  // Measure the time for the echo to return
  long duration = pulseIn(echo_pin, HIGH);

  // Calculate distance in cm
  float distance = (duration / 2.0) * 0.0343;

  // Print the distance
  if (distance >= 10) {
    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");
  } else {
    Serial.println("Error: Out of range");
    delay(500);
  }

  // Control the LED based on distance
  if (distance <= 10) {
    digitalWrite(led_pin, HIGH); // Turn LED ON
  } else {
    digitalWrite(led_pin, LOW);  // Turn LED OFF
  }

  // Short delay before next measurement
  delay(100);
}