gistfile1.txt

// code is for 16MHz adafruit trinket (atmel ATtiny85)
int red   = 0;
int green = 1;
int blue  = 2;

void setup() {
  // put your setup code here, to run once:
  pinMode(red,   OUTPUT);
  pinMode(green, OUTPUT);
  pinMode(blue,  OUTPUT);
}

int t[3]           = {0,0,0};
int permil[3]      = {0,0,0};
int light[3]       = {red,green,blue};
int timer[3]       = {0,0,0};
int dir[3]         = {1,1,1};
int rate[3]        = {800,600,1100};
int flicker_max[3] = {400,400,400};
int attenuation[3] = {400,400,50};
int steps[3]       = {4,4,1};

void manageLight(int i){

  /* duty cycle determines instantaneous brightness */
  t[i]++;
  if(t[i] < permil[i]){
    digitalWrite(light[i], HIGH);
  }
  else if(t[i] < flicker_max[i]){
    digitalWrite(light[i], LOW);
  }
  else{
    t[i] = 0;
  }

  /* second, slower timer controls duty cycle bounce */
  timer[i]++;
  if(timer[i] > rate[i]){
    timer[i] = 0;
    permil[i] += dir[i] * steps[i];
    if(permil[i] == attenuation[i] || permil[i] == 0) dir[i] *= -1;
  }
}

void loop() {
  manageLight(0);
  manageLight(1);
  manageLight(2);
}