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,HIGH);
  delay (5000);
 }
 else
 {
  digitalWrite(LED, LOW);
  delay(5000);
 }
}