int val = 0 ;  
 void setup()  
 {  
   Serial.begin(9600); // sensor buart rate  
   pinMode(3,INPUT);  // LDR Sensor output pin connected  
   pinMode(4,OUTPUT); //  LED PIN  
 }  
 void loop()   
 {  
  val = digitalRead(3); // LDR Sensor output pin connected  
  Serial.println(val); //  see the value in serial mpnitor in Arduino IDE  
  delay(10);  
  if(val == 0 )  
  {  
   digitalWrite(4,HIGH); // LED ON  
   delay(1000);  
  }  
  else  
  {  
   digitalWrite(4,LOW); // LED OFF  
  }  
  }
								
							
							

	
								
void setup()  
 {  
 Serial.begin(9600); // sensor buart rate  
 pinMode(4,OUTPUT); // led pin  
 }  
 void loop()  
 {  
 int s1=analogRead(A0); // LDR Sensor output pin connected  
 Serial.println(s1);  
 delay(50);  
 if(s1< 500 )  
 {  
 digitalWrite(4,HIGH); // led ON  
 }  
 else  
 {  
 digitalWrite(4,LOW); // Red led OFF  
 }  
 }