#define TRIG_PIN 3
#define ECHO_PIN 2
#define BUZZER_PIN 9

long duration;
int distance;

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

void loop() {
  // Clear the TRIG pin
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);

  // Set TRIG pin HIGH for 10ms
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Read the ECHO pin
  duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate distance in cm
  distance = duration * 0.0344 / 2;

  // Print the distance to the Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Make buzzer sound based on distance
  if (distance < 150) {
    tone(BUZZER_PIN, 1000); // Play tone at 1000Hz
  } else {
    noTone(BUZZER_PIN); // Stop the tone
  }

  delay(500);
}