const int ldr=4;
const int led=5;
int input_val=0;
void setup()
{
  Serial.begin(9600);
  pinMode(led, OUTPUT);
}
void loop()
{
  input_val=analogRead(ldr);
  Serial.print("LDR value is : " );
  Serial.print(input_val);
  delay(1000);
  if (input_val>800)
  {
    digitalWrite(led,LOW);
    delay(1000);
  }
  else
  {
    digitalWrite(led,HIGH);
    delay(5000);
  }
}