Arduino mit SRF05

#define echoPin 3
#define trigPin 2

int rot = 8;
int gelb = 9;
int gruen = 10;

void setup(){
  Serial.begin(9600);
  pinMode(echoPin, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(rot, OUTPUT);
  pinMode(gelb, OUTPUT);
  pinMode(gruen, OUTPUT);
}

void loop(){
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  int distance = pulseIn(echoPin, HIGH);
  distance= distance/58;
  Serial.println(distance);
  delay(100);
  if (distance <= 15) {
    digitalWrite(gelb, LOW);
    digitalWrite(rot, HIGH);
    digitalWrite(gruen, LOW);
  }
  if (distance <= 35 && distance > 15) {
    digitalWrite(gelb, HIGH);
    digitalWrite(rot, LOW);
    digitalWrite(gruen, LOW);
  }
  if (distance > 35) {
    digitalWrite(gelb, LOW);
    digitalWrite(rot, LOW);
    digitalWrite(gruen, HIGH);
  }
}