char data = 0;            
void setup()
{
    Serial.begin(9600);                                 
    pinMode(13, OUTPUT);  
}
void loop()
{
   if(Serial.available() > 0)      
   {
      data = Serial.read();        
      Serial.print(data);          
      Serial.print("\n");        
      if(data == '1')              
         digitalWrite(13, HIGH);   
      else if(data == '0')         
         digitalWrite(13, LOW);    
   }
}