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.println(input_val);
  delay(1000);
  if(input_val>800)
  {
    digitalWrite(LED,HIGH);
    delay(1000);
  }
  else
  {
    digitalWrite(LED,LOW);
    delay(1000);
  }
}