#define TRIG_PIN 2 // GPIO pin connected to the trigger pin of the ultrasonic sensor
#define ECHO_PIN 4 // GPIO pin connected to the echo pin of the ultrasonic sensor

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

void loop() {
  long duration, distance; // Variables to hold duration and distance values
  
  // Send a 10us pulse to trigger pin
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  
  // Measure the duration of the pulse on echo pin
  duration = pulseIn(ECHO_PIN, HIGH);
  
  // Calculate distance in cm
  distance = duration * 0.034 / 2; // Speed of sound in air = 0.034 cm/µs
  
  // Print the distance measured
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  
  delay(1000); // Delay before next measurement
}