int trigger=PD6;                // This Pin bekomms the name Trigger will cause a sound wave as sooon as programm starts
int echo=PD5;                   // If the Trigger Sound wave is reflected from the wall ...
                                // and returns to the sensor, the sensor will send a 5V signal to this pin (echo).
long duration=0;                // Startvalue for this variable is 0
long distance=0;                // Startvalue for this variable is 0
void setup()
{
Serial.begin (9600);            // This is the Baudrate 9600 Bit/second which I will use for the readings
pinMode(trigger, OUTPUT);       //Pin named "trigger" will be used as output 
pinMode(echo, INPUT);           //Pin named "echo" will be used as output 
}
void loop()                      // This part of the programm will repeat during the running time of the programm
{
digitalWrite(trigger, LOW);       // Pin PD6 (trigger) gets a 0V signal from the microcontroller board (ATmega328p)
delay(5); 
digitalWrite(trigger, HIGH);       //PD6 (trigger) 
delay(10);
digitalWrite(trigger, LOW);

duration = pulseIn(echo, HIGH);
distance = (duration/2) * 0.03432; 

if (distance >= 500 || distance <= 0) 
{
Serial.print(0); 
Serial.print(" ");
Serial.println(0);
}
else 
{
Serial.print(duration);
//Serial.print("\ milisecond");
//Serial.print("\t");
Serial.print(" ");
Serial.println(distance);
//Serial.print("\t");
//Serial.println("cm"); 
}
delay(1000); 
}