#define lightIn A2 // the LDR
#define LED 13 // the LED

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

void loop() {
  // put your main code here, to run repeatedly:
  delay(100);
  int val = analogRead(lightIn); // Reading the binary value of the LDR
  String dn = ""; // dn (Day/Night) represents whether the lights are on 
  if (val >= 256) // If the light is below 500 Lux (the light level considered for night)
  {
    digitalWrite(LED, LOW); // if night then the light is off
    dn = "OFF";
  }
  else
  {
    digitalWrite(LED, HIGH); // if day then the light is on
    dn = "ON";
  }
  Serial.print("Ambient Light level is: ");
  Serial.print(val);
  Serial.print(" and the lights are ");
  Serial.println(dn);
}