int inputPin=4;  // define ultrasonic signal receiver pin  ECHO to D4
      int outputPin=5; // define ultrasonic signal transmitter pin  TRIG to D5
      void setup()
      {
        Serial.begin(9600);
        pinMode(inputPin, INPUT);
        pinMode(outputPin, OUTPUT);
       }
     void loop()
    {
        digitalWrite(outputPin, LOW);
        delayMicroseconds(2);
        digitalWrite(outputPin, HIGH); // Pulse for 10μs to trigger ultrasonic detection
        delayMicroseconds(10);
        digitalWrite(outputPin, LOW);  
        int distance = pulseIn(inputPin, HIGH);  // Read receiver pulse time
        distance= distance/58;   // Transform pulse time to distance
        Serial.println(distance);   //Ourput distance                
        delay(50);  
     }