#define LDR A1              // analog pin to which LDR is connected
#define LED 1               // pin to which LED is connected
const int sensitivity = 40; // setting the light sensitivity

int LDRValue = 0;           // variable to store LDR values
int threshold;              // light sensitivity threshold

void setup()
{
  pinMode(LED, OUTPUT);                       // configure LED pin to behave as output
  threshold = analogRead(LDR) - sensitivity;  // set light sensitivity threshold
}

void loop()
{
  LDRValue = analogRead(LDR);                 // read LDR value

  if (LDRValue <= threshold)                  // if the LDR reading is lower than the threshold
  {
    for (int i = 0; i <= 50; i++) {           // blink LEDs
      digitalWrite(LED, HIGH);
      delay(50);
      digitalWrite(LED, LOW);
      delay(50);
    }
    delay(1000);
    threshold = analogRead(LDR) - sensitivity; // set light sensitivity threshold
    delay(1000);
  }
  else
  {
    digitalWrite(LED, LOW);
  }
}