void setup() 
{
  Serial.begin(115200);
  pinMode(13,OUTPUT);
}

void loop() 
{
  int AN0 = analogRead(A0);
  float V = AN0*5.0/1023;
  float R = 5.0*10000/V - 10000;
  float lux = 12518931*pow (R,-1.405);
  Serial.print(V);
  Serial.print(",");
  Serial.print(R);
  Serial.print(",");
  Serial.print(lux);

  if(lux > 25.0)
    digitalWrite(13,0);
  if(lux > 10.0)
    digitalWrite(13,1);
  delay(200);
}