int LeftMotorForward = 6; 
int LeftMotorReverse = 7; 
int RightMotorForward = 8;
int RightMotorReverse = 9;


const int sensorPin = A0;    // pin that the sensor is attached to
const int ledPin = 13;        // pin that the LED is attached to

// variables:
int sensorValue = 0;         // the sensor value
int sensorMin = 1023;        // minimum sensor value
int sensorMax = 0;           // maximum sensor value


void setup()
{  

  Serial.begin (9600); 
  
  pinMode(LeftMotorForward, OUTPUT); 
  pinMode(LeftMotorReverse, OUTPUT);     
  pinMode(RightMotorForward, OUTPUT); 
  pinMode(RightMotorReverse, OUTPUT); 



 // turn on LED to signal the start of the calibration period:
  pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);

  // calibrate during the first five seconds
  while (millis() < 5000) {
    sensorValue = analogRead(sensorPin);

    // record the maximum sensor value
    if (sensorValue > sensorMax) {
      sensorMax = sensorValue;
    }

    // record the minimum sensor value
    if (sensorValue < sensorMin) {
      sensorMin = sensorValue;
    }
  }//Ende while

  // signal the end of the calibration period
  digitalWrite(13, LOW);

}//Ende Setup


void loop()
{

// read the sensor:
  sensorValue = analogRead(sensorPin);

  // apply the calibration to the sensor reading
  sensorValue = map(sensorValue, sensorMin, sensorMax, 0, 255);

  // in case the sensor value is outside the range seen during calibration
  sensorValue = constrain(sensorValue, 0, 255);

//    Serial.print(sensorValue); 
//    Serial.println(" sensorValue"); 


vor();


  if (sensorValue < 80) { //hell
       stoppen();
       rechts();
    }

    

delay(100);  
}// Ende Loop

///////////// Subroutinen ////////////////////

 void stoppen(){
   digitalWrite(LeftMotorForward, LOW);   
   digitalWrite(LeftMotorReverse, LOW);   
   digitalWrite(RightMotorForward, LOW);  
   digitalWrite(RightMotorReverse, LOW);   
}
 
    
void rechts(){

   digitalWrite(RightMotorForward, HIGH);   
   digitalWrite(LeftMotorReverse, HIGH);   
   delay(100);           
 
   digitalWrite(RightMotorForward,LOW);   
   digitalWrite(LeftMotorReverse, LOW);   
   delay(10);             
}
    
void vor(){
   digitalWrite(RightMotorForward, HIGH); 
   digitalWrite(LeftMotorForward, HIGH);  
}

void zurueck(){
   digitalWrite(RightMotorReverse, HIGH); 
   digitalWrite(LeftMotorReverse, HIGH);  
}