const int TRIGGER_PIN = 4; // Trigger pin of the ultrasonic sensor
const int ECHO_PIN = 13; // Echo pin of the ultrasonic sensor

void setup() {
  pinMode(TRIGGER_PIN, OUTPUT); // Set trigger pin as an output
  pinMode(ECHO_PIN, INPUT); // Set echo pin as an input
  Serial.begin(9600); // Initialize serial communication
}

void loop() {
  // Generate a 10us pulse on the trigger pin to start the ultrasonic signal
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER_PIN, LOW);

  // Measure the duration of the echo signal
  long duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate the distance in cm
  float distance = duration * 0.034 / 2;

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

  // Wait for 500ms before sending the next ultrasonic signal
  delay(500);
}