int ldrPin = A0;
int ledPin = 9;

void setup() {
  // put your setup code here, to run once:
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  int ldrValue = analogRead(ldrPin);
  Serial.print("Value : ");
  Serial.println(ldrValue);

  if(ldrValue > 500){
    digitalWrite(ledPin, HIGH);
  }else{
    digitalWrite(ledPin, LOW);
  }
  delay(200);
}