const int ledPin = 8; //pin at which LED is connected 
const int ldrPin = A0; //pin at which LDR is connected 
int threshold = 600;
//int threshold2 = 80;
void setup() 
{
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT); //Make LED pin as output 
  pinMode(ldrPin, INPUT); //Make LDR pin as input 
}
void loop()
{
  int ldrStatus = analogRead(ldrPin); //saving the analog values received from LDR 
  if (ldrStatus <= threshold) //set the threshold value below at which the LED will turn on
  {               //you can check in the serial monior to get approprite value for your LDR 
    digitalWrite(ledPin, HIGH);  //Turing LED ON 
    Serial.print("Its DARK, Turn on the LED : ");
    Serial.println(ldrStatus);
  }
  else
  
  {
    digitalWrite(ledPin, LOW); //Turing OFF the LED 
    Serial.print("Its BRIGHT, Turn off the LED : ");
    Serial.println(ldrStatus);
  }
}