#define TRIGGER_PIN  2
#define ECHO_PIN     15
#define BUZZER_PIN   13

void setup() {
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
 
  Serial.begin(115200);
}

void loop() {
  long duration, distance;
  
  digitalWrite(TRIGGER_PIN, LOW);
  delay(100);
  digitalWrite(TRIGGER_PIN, HIGH);
  delay(100);
  digitalWrite(TRIGGER_PIN, LOW);
  
  duration = pulseIn(ECHO_PIN, HIGH);
  
  distance = (duration / 2) / 29.1; // Calculate distance in cm
  
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  
  if (distance < 30) { // Adjust this threshold as needed
    digitalWrite(BUZZER_PIN, HIGH);
    delay(100);
    digitalWrite(BUZZER_PIN, LOW);
  }
  
  delay(100); // Delay between readings
}