int ledPin = 5;
int lux;
int i;

void setup() {
  // put your setup code here, to run once:
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  lux=analogRead(A0);
  i= map(lux, 0, 1023, 0, 255);
  analogWrite(ledPin,i);
}