#define LDR_PIN 25
float ADC_value=3.3 / 4095.0;
void setup() {
    Serial.begin(9600);
    pinMode(LDR_PIN,INPUT);
}

void loop() {
  int ldr_data = analogRead(LDR_PIN);
  int lux = int((250.000000/(ADC_value*ldr_data))-50.000000);
  Serial.println(lux,1);
  delay(1000); 

  if(lux<100){
    Serial.println("turn off");
  }
  else{
    Serial.println("turn on");
  }
}