#define triggerPin 2 // Pin connected to the TRIGGER pin of the ultrasonic sensor
#define echoPin 4    // Pin connected to the ECHO pin of the ultrasonic sensor
#define buzzerPin 5  // Pin connected to the buzzer

void setup() {
  pinMode(triggerPin, OUTPUT);// Initialize the TRIGGER pin as an output
  pinMode(echoPin, INPUT);   // Initialize the ECHO pin as an input
  pinMode(buzzerPin, OUTPUT);// Initialize the buzzer pin as an output
}

void loop() {
  // Generate trigger pulse
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  // Measure the pulse from the echo pin
  long duration = pulseIn(echoPin, HIGH);
 // Convert pulse duration to distance (Speed of sound: 343m/s, 0.0343 cm/us, accounting for round-trip travel)
  int distance = duration * 0.0343 / 2;

  // If an object is detected within 50cm, activate the buzzer
  if (distance < 50) {
    tone(buzzerPin, 1000, 1000); // Generate a 1000ms beep
    delay(1000);                 // Wait for 1000ms
    noTone(buzzerPin);          // Turn off the buzzer
    delay(100);                 // Wait for 100ms
  }

  delay(100); // Wait for 100ms before the next reading
}