int trigpin = 4; // Example pin number for TRIG
int echopin = 5; // Example pin number for ECHO
long duration;
long distance;

void setup() {
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
  Serial.begin(9600);
}

void loop() {
  // Clear the TRIG pin
  digitalWrite(trigpin, LOW);
  delayMicroseconds(2);

  // Trigger the sensor
  digitalWrite(trigpin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin, LOW);

  // Read the ECHO pin duration
  duration = pulseIn(echopin, HIGH);

  // Check if duration is zero
  if (duration == 0) {
    Serial.println("No echo received.");
  } else {
    // Calculate distance (duration * speed of sound / 2)
    distance = duration * 0.0343 / 2;

    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");
  }

  delay(500); // Wait half a second
}