LED brightness control

Using Arduino Programming Questions
12

MaJiG:
Here's my try:

Connect a SPST N.O. momentary from pin 8 to GND with no resistor.
Connect an LED from pin 9 to an LED in series with a current-limiting resistor (220 to 330 ohm) to GND.

My code:

int but = 8;

int led = 9;
int val = 0;

void setup()
{
 pinMode(but, INPUT_PULLUP);
 pinMode(led, OUTPUT);             // not needed, but I like to be explicit
}

void loop()
{
 if(digitalRead(but) == LOW)
 {
   //here: the button is pushed
    val += 20;                                 // increment the brightness of the LED by 1/24th
   val = min(val, 255);                     // maximum PWM value is 255
 }
 else
 {
   //here: the button has been released
   val = 0;                                  // turn the LED OFF
 }

analogWrite(led,val);                 // adjust the PWM
 delay( 250 );                           // give yourself a chance to see the result
}




should take about 3 seconds from OFF to full brightness. If you need it to be quicker, adjust the delay time
the delay also tends to debounce the switch too

After inspected the code, I realised that you also used "LOW" for if statement with buttons. Why is it so ?
I think if the button is not pushed it should be act as "LOW" and the led starts shining, but it doesn't and the code works pretty well.
But didn't get the idea underlying.