#define ENCA 2 // YELLOW
#define ENCB 3 // WHITE
int dir;
int dr= 12;
int dl=13;
int doel=500;

volatile int posi = 0; // specify posi as volatile

void setup() {
  Serial.begin(9600);
  pinMode(ENCA,INPUT);
  pinMode(ENCB,INPUT);
  pinMode(dr,OUTPUT);
  pinMode(dl,OUTPUT);

  attachInterrupt(digitalPinToInterrupt(ENCA),readEncoder,RISING);
}

void loop() {
  // Read the position in an atomic block to avoid a potential
  // misread if the interrupt coincides with this code running
  // see: https://www.arduino.cc/reference/en/language/variables/variable-scope-qualifiers/volatile/
  int pos = 0; 
 
    pos = posi;
    dir = doel - pos;
    if (dir>0)
    {
      digitalWrite(dr,HIGH);
            Serial.println(rechts)
    }
    else
    {
      
      digitalWrite(dl,HIGH);
      Serial.println(links)
    }
  }
  
  Serial.println(pos);
}

void readEncoder(){
  int b = digitalRead(ENCB);
  if(b > 0){
    posi++;
    
  }
  else{
    posi--;
  }
}