void setup()  
 {  
   Serial.begin(9600); // sensor buart rate  
   pinMode(A0,INPUT);  // LDR Sensor 
   pinMode(13,OUTPUT); //  LED PIN  
 }  

 void loop()   
 {  
  int val = analogRead(A0); 
  Serial.println(val); 

  if(val > 300 )  
  {  
   digitalWrite(13,LOW); // LED OFF  
   
  }  
  else  
  {  
   digitalWrite(13,HIGH); // LED ON  
  }  
delay(1000);
  }