int trigger = 12;
int echo = 14; 

long dauer = 0;
long entfernung = 0;

int GRÜN = 16;
int ROT = 17;

void setup() {
  
  Serial.begin(115200);
  pinMode(trigger, OUTPUT);
  pinMode(echo, INPUT);
}

void loop() {

  
  digitalWrite(trigger, LOW);
  delay(5);
  digitalWrite(trigger, HIGH);
  delay(10);
   digitalWrite(trigger, LOW);
   dauer = pulseIn(echo, HIGH);
   entfernung = (dauer/2) * 0.03432;

   Serial.println(entfernung);

  if(entfernung<=50){
    Serial.println("ROT");
  }else{
    Serial.print("GRÜN");
  }

   delay(1009);
}