int buzzer = 18;
int triggerPin = 5;
int echoPin = 17;

// Function to measure the time taken for ultrasonic waves to return
long readTime(int triggerPin, int echoPin) {
  pinMode(triggerPin, OUTPUT);
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  pinMode(echoPin, INPUT);
  return pulseIn(echoPin, HIGH);
}

void initializeBuzzer() {
  ledcSetup(0, 1000, 8);  // LEDC channel, frequency, resolution
  ledcAttachPin(buzzer, 0);
}

void setup() {
  Serial.begin(9600);
  
  // Set the buzzer pin as an output pin
  pinMode(buzzer, OUTPUT);

  // Initialize the buzzer
  initializeBuzzer();
}

void loop() {
  int distance;
  
  // Calculate the distance using the readTime function
  distance = 0.01715 * readTime(triggerPin, echoPin);
  
  // Print the distance to the serial monitor
  Serial.print("distance: ");
  Serial.print(distance);
  Serial.println("cm");

  // Check the distance range and produce corresponding tones
  if (distance > 50 && distance < 100) {
    tone(buzzer, 1000); // Produce a tone of 1000Hz
  } else if (distance < 50 && distance > 25) {
    tone(buzzer, 3000); // Produce a tone of 3000Hz
  } else if (distance < 25 && distance <= 100) {
    tone(buzzer, 5000); // Produce a tone of 5000Hz
  } else {
    noTone(buzzer); // Turn off the buzzer if distance is above 100
  }

  delay(100); // Add a delay to make the output more readable
}