// Timer/Fader 01
//
// A delay-free timer for a single LED that fades in and out

// Timer variables
long timer = 0;
int offset = 10;              // Change this for faster or slower fades                     
// Pin variable
int pwm = 11;
// Direction variable
int upDown = 1;
// pwm value holding variable
int val1 = 0;

//Setup
void setup() {                  // The standard stuff...
    Serial.begin(9600);         // Setup the serial communications so we can debug
    pinMode(pwm, OUTPUT);  
    timer = millis();          
}

// Das Loop...
void loop() {
  // Timer
  if((timer + offset) < millis() ) { 
     doFade();              
     timer = millis();  
  }
}

// Fade function
void doFade() {
  if(val1 >= 50) { upDown = -1; }  // The LED on my board only appears to be getting
  if(val1 <= 0)  { upDown = 1;  }  // brighter on pwm values up to 50 (out of 255)
  val1 = val1 + ( 1 * upDown);     // so, I've set the max value to change the direction
  analogWrite(pwm, val1);          // to 50.
}