#define TRIG_PIN 12
#define ECHO_PIN 13
#define BUZZER_PIN 16

void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);  
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
}

void loop() {
  long duration, distance;

  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  duration = pulseIn(ECHO_PIN, HIGH);
  distance = (duration * 0.034 / 10); // Convert to cm

  if (distance < 10) { // Adjust distance threshold as needed
    digitalWrite(BUZZER_PIN, HIGH); // Turn on buzzer/LED
  } else {
    digitalWrite(BUZZER_PIN, LOW); // Turn off buzzer/LED
  }

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  delay(5000);
}