const int LDR_PIN =34;
const int LED1 =12;
const int LED2 =13;
const int LED3 =14;
const int LED4 =32;

void setup()
 {
   pinMode(LDR_PIN,INPUT);
   pinMode(LED1, OUTPUT);
   pinMode(LED2, OUTPUT);
   pinMode(LED3, OUTPUT);
   pinMode(LED4, OUTPUT);
}

void loop() 
{
  int sensorValue=analogRead(LDR_PIN);
  if(sensorValue<1000)

 {
   digitalWrite(LED1, HIGH);
   digitalWrite(LED2, HIGH);
   digitalWrite(LED3, HIGH);
   digitalWrite(LED4, HIGH);
   delay(1000);
 }
  
  else if(sensorValue<2000)
  {
    digitalWrite(LED1, LOW);
   digitalWrite(LED2, HIGH);
   digitalWrite(LED3, HIGH);
   digitalWrite(LED4, HIGH);
   delay(1000);
  }
  else if(sensorValue<3000)
  {
    digitalWrite(LED1, LOW);
   digitalWrite(LED2, LOW);
   digitalWrite(LED3, HIGH);
   digitalWrite(LED4, HIGH);
   delay(1000);
  }
  else if(sensorValue<4000)
  {
    digitalWrite(LED1, LOW);
   digitalWrite(LED2, LOW);
   digitalWrite(LED3, LOW);
   digitalWrite(LED4, HIGH);
   delay(1000);
  }

}