LED Fading For Beginners

1int led = 9;           // the PWM pin the LED is attached to
2int brightness  = 0;    // how bright the LED is
3int fadeAmount = 5;    // how many points to  fade the LED by
4
5// the setup routine runs once when you press reset:
6void  setup() {
7  // declare pin 9 to be an output:
8  pinMode(led, OUTPUT);
9}
10
11//  the loop routine runs over and over again forever:
12void loop() {
13  // set  the brightness of pin 9:
14  analogWrite(led, brightness);
15
16  // change the  brightness for next time through the loop:
17  brightness = brightness + fadeAmount;
18
19  // reverse the direction of the fading at the ends of the fade:
20  if (brightness  <= 0 || brightness >= 255) {
21    fadeAmount = -fadeAmount;
22  }
23  // wait  for 30 milliseconds to see the dimming effect
24  delay(30);
25}