// Define pins
const int trigPin = 5;
const int echoPin = 18;

long duration;
float distanceCm;

void setup() {
  Serial.begin(115200);       // Start the serial monitor
  pinMode(trigPin, OUTPUT);   // Set trigPin as an OUTPUT
  pinMode(echoPin, INPUT);    // Set echoPin as an INPUT
}

void loop() {
  // Clear the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Trigger the sensor by sending a 10us HIGH pulse
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the echoPin (pulse duration)
  duration = pulseIn(echoPin, HIGH, 30000);  // timeout 30ms = ~5 meters

  // Calculate distance in centimeters
  distanceCm = duration * 0.0343 / 2;

  // Check if distance is valid
  if (duration == 0) {
    Serial.println("Out of range");
  } else {
    Serial.print("Distance: ");
    Serial.print(distanceCm);
    Serial.println(" cm");
  }

  delay(500);  // Wait before next measurement
}