// PWM pins  are identified with a "~" sign, like ~3, ~5, ~6, ~9, ~10 and ~11.
#include <Arduino.h>
const int ledPin = 11;
int brightness = 0;

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

void loop() {
  // put your main code here, to run repeatedly:
  int darkness = analogRead(A0);

  if (darkness > 900)  {
    brightness = 255;
  } else if (darkness > 700)  {
    brightness = 180;
  } else if (darkness > 500)  {
    brightness = 100;
  } else {
    brightness = 0;
  }
  
  analogWrite(ledPin, brightness);
  delay(1000);
}