int val = 0;
 
void setup()
{
    Serial.begin(9600);
 
    // Turn on LED when program starts
    pinMode(13, OUTPUT);

}
 
void loop()
{

    if(Serial.available()){
      val = Serial.read();
    }
    if(val == 1){
      digitalWrite(13, HIGH);
    }else if(val == 0){
      digitalWrite(13, LOW);
    }    
    
}