#define TRIG_PIN 5
#define ECHO_PIN 18

long duration;
float distance;

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
    pinMode(ECHO_PIN, INPUT);
      Serial.begin(9600);
      }

      void loop() {
        // Clear trigger
          digitalWrite(TRIG_PIN, LOW);
            delayMicroseconds(2);

              // Send ultrasonic pulse
                digitalWrite(TRIG_PIN, HIGH);
                  delayMicroseconds(10);
                    digitalWrite(TRIG_PIN, LOW);

                      // Read echo time
                        duration = pulseIn(ECHO_PIN, HIGH);

                          // Calculate distance (cm)
                            distance = duration * 0.034 / 2;

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

                                    delay(1000);
                                    }