debounce_button

int switchPin = 6;
int ledPin = 4;
boolean lastButton = LOW;
boolean currentButton = LOW;
int ledLevel = 0;

void setup()
{
	pinMode(switchPin, INPUT);
	pinMode(ledPin, OUTPUT);
}

boolean debounce(boolean last)
{
	boolean current = digitalRead(switchPin);
	if (last != current)
	{
		delay(5);
		current = digitalRead(switchPin);
	}
	return current;
}

void loop()
{
  currentButton = debounce(lastButton);
  if (lastButton == LOW && currentButton == HIGH)
  {
    ledLevel = ledLevel + 51;
  }
  
  lastButton = currentButton;
  if (ledLevel > 255) ledLevel = 0;
  analogWrite(ledPin, ledLevel);
  delay (5);
}