const int LED = 9;
const int BUTTON = 7;
int val = 0;
int old_val = 0;
int state = 0;
int brightness = 128;
unsigned long startTime = 0;

void setup() {
 // pinMode (LED, OUTPUT);
  pinMode (BUTTON, INPUT);
}

void loop() {
  val = digitalRead (BUTTON);
  if ((val == HIGH) && (old_val == LOW)) {
    state = 1 - state;
    startTime = millis();
    delay (10);
  }
  if ((val == HIGH) && (old_val == HIGH)) {
    if (state == 1 && (millis() - startTime) > 500) {
      brightness++;
      delay(10);
      if (brightness > 255) {
        brightness = 0;
      }
    }
  }
  old_val = val;
  if (state == 1) {
    analogWrite (LED, brightness);
  } else {
    analogWrite (LED, 0);
  }
}