arduino_fade.ino

int led = 9;        // the PWM pin the LED is attached to
int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by

void setup() {
    // declare pin 9 to be an output:
    pinMode(led, OUTPUT);
}


void loop() {
    // set the brightness of pin 9:
    analogWrite(led, brightness);

    // change the brightness for next time through the loop:
    brightness = brightness + fadeAmount;

    // reverse the direction of the fading at the ends of the fade:
    if (brightness <= 0 || brightness >= 255) {
        fadeAmount = -fadeAmount;
    }

    // wait for 30 milliseconds to see the dimming effect
    delay(30);
}