int incomingByte;   
char Data[8];
int i;
unsigned long Tempo;
 
void setup()
{
  Serial.begin(9600);
}
 
void loop(){
 
   do {
     if (Serial.available()) {       
       Data[i] = Serial.read();
       i++;
       }     
     if(i<1)Tempo = millis(); 
     } while (i<5&&(millis()-Tempo) < 500);
 
   Data[i] = 0;    
   incomingByte = atoi(Data);  
   i=0;
   /// einfügen Kontrolle ob Wert zu groß oder negativ.
   Serial.println(incomingByte);
   AnalogWrite(pin,incomingByte);
}