const int trigpin=12;
const int echopin=13;
void setup(){
    Serial.begin(9600);
      pinMode(12, OUTPUT);
        pinMode(13, INPUT);
        }

        void loop() {
          long duration, distance;
            digitalWrite(12, LOW);  // Reset trigger pin
              delayMicroseconds(2);
                digitalWrite(12, HIGH);  // Send ultrasonic pulse
                  delayMicroseconds(10);
                    digitalWrite(12, LOW);
                      duration = pulseIn(13, HIGH);  // Measure echo time
                        distance = (duration / 2) * 0.034;  // Calculate distance (cm)
                          Serial.print("Distance: ");
                            Serial.print(distance);
                              Serial.println(" cm");
                                delay(500);
                                }