Color-O-Tron 5000 Lighting System for the Arduino

Color-O-Tron_5000.ino

#include <math.h>

#define DEBUG_BAUD 9600

// def to enable, undef to disable
#define DEBUG
#define TEXT_ONLY

#define UP 1
#define DOWN -1

struct Color {
  int r, g, b;
};

// Interrupt pins
const int bModePin = 7;

// Digital PWM output pins
const int oRedChannel = 8;
const int oGreenChannel = 10;
const int oBlueChannel = 12;

// Analog input pins
const int pRedPot = 0;
const int pGreenPot = 1;
const int pBluePot = 2;

struct Color natural_white;
struct Color strand_color;
int color_direction;

int mode_state = 0;
int mode_state_direction = 1;

struct Color initDefault() {
  struct Color c;

  c.r = 128;
  c.g = 128;
  c.b = 128;

  return c;
}

struct Color initNaturalWhite() {
  struct Color c;

  /* this is merely a close approximation of
     natural white
  */

  int temp = 27; // 2700K

  c.r = 255;
  c.g = 99.4708025861 * log(temp) - 161.1195681661;
  c.b = 138.5177312231 * log(temp - 10) - 305.0447927307;

  return c;
}

/* Linear Fade
   Performs a uniform fade between all channels from
   0 to 255, oscillating between extremes. Updates
   once every 0.1 seconds.
*/
Color linearFade() {
  struct Color c;

  int nextColor = strand_color.r + (0.1 * color_direction);

  if (nextColor >= 255) {
    color_direction = DOWN;
    c.r = 254;
    c.g = 254;
    c.b = 254;
  } else if (nextColor <= 0) {
    color_direction = UP;
    c.r = 1;
    c.g = 1;
    c.b = 1;
  }

  delay(10); // 0.1s per frame

  return c;
}

/* Spectrum Fade
   Performs a visible color spectrum fade oscillating
   between red and violet.
*/
Color spectrumFade() {
  struct Color c;

  if (color_direction == UP) {
    if (strand_color.r < 255) {
      c.r = strand_color.r + 1;
      c.g = 0;
      c.b = 0;
    } else if (strand_color.r >= 255 && strand_color.g < 255) {
      c.r = 255;
      c.g = strand_color.g + 1;
      c.b = 0;
    } else if (strand_color.r >= 255 && strand_color.g >= 255) {
      c.r = 255;
      c.g = 255;
      c.b = strand_color.b + 1;
    } else if (strand_color.r >= 255 && strand_color.g >= 255 && strand_color.b >= 255) {
      c.r = 255;
      c.g = 255;
      c.b = 255;
      color_direction = DOWN;
    }
  } else {
    if (strand_color.r > 0) {
      c.r = strand_color.r - 1;
      c.g = 255;
      c.b = 255;
    } else if (strand_color.r <= 0 && strand_color.g > 0) {
      c.r = 0;
      c.g = strand_color.g - 1;
      c.b = 255;
    } else if (strand_color.r <= 0 && strand_color.g <= 0 && strand_color.b > 0) {
      c.r = 0;
      c.g = 0;
      c.b = strand_color.b - 1;
    } else if (strand_color.r <= 0 && strand_color.g <= 0 && strand_color.b <= 0) {
      c.r = 0;
      c.g = 0;
      c.b = 0;
      color_direction = UP;
    }
  }

  return c;
}

/* Potentiometer Fade
   Uses three potentiometers to set red, green, and blue
   for the entire strand.
*/
Color potFade() {
  struct Color c;

  c.r = map(analogRead(pRedPot), 0, 1024, 0, 255);
  c.g = map(analogRead(pGreenPot), 0, 1024, 0, 255);
  c.b = map(analogRead(pBluePot), 0, 1024, 0, 255);

  return c;
}

// next color generator distpatch function
Color nextColorDispatch(int mode) {
  struct Color c;

  switch (mode) {
    case 1:
      c = linearFade();
      break;
    case 2:
      c = spectrumFade();
      break;
    case 3:
    //c = potFade();
    //break;
    case 0:
    default:
      c = natural_white; // solid natural white
      break;
  }

  return c;
}

void setModeState() {
  static unsigned long last_interrupt_time = 0;
  unsigned long interrupt_time = millis();

  if (interrupt_time - last_interrupt_time > 200) {
    mode_state = mode_state + mode_state_direction;
    if (mode_state > 4) {
      mode_state_direction = DOWN;
      mode_state = 3;
    } else if (mode_state < 0) {
      mode_state_direction = UP;
      mode_state = 1;
    }

#ifdef DEBUG
    Serial.print("Changing mode to ");
    Serial.println(mode_state);
#endif
  }

  last_interrupt_time = interrupt_time;
}


void setup() {
  strand_color = initDefault();
  natural_white = initNaturalWhite();

#ifndef TEXT_ONLY
  pinMode(bModePin, INPUT);

  digitalWrite(oRedChannel, strand_color.r);
  digitalWrite(oGreenChannel, strand_color.g);
  digitalWrite(oBlueChannel, strand_color.b);
#endif

#ifdef DEBUG
  Serial.begin(DEBUG_BAUD);
#endif

  attachInterrupt(digitalPinToInterrupt(bModePin), setModeState, RISING);
}

void loop() {
  noInterrupts();
  int current_mode = mode_state;
  interrupts();

  /* now generate next strand color and set. do this
     every frame so that it can be tested with a
     serial debugging session
  */
  strand_color = nextColorDispatch(current_mode);

#ifndef TEXT_ONLY
  analogWrite(oRedChannel, strand_color.r);
  analogWrite(oGreenChannel, strand_color.g);
  analogWrite(oBlueChannel, strand_color.b);
#endif

#ifdef DEBUG
  Serial.print("Color { r: ");
  Serial.print(strand_color.r);
  Serial.print(", g: ");
  Serial.print(strand_color.g);
  Serial.print(", b: ");
  Serial.print(strand_color.b);
  Serial.print(" }, state: ");
  Serial.println(current_mode);
#endif
}