/*
* Code for cross-fading 3 LEDs, red, green and blue, or one tri-color LED, using PWM
* The program cross-fades slowly from red to green, green to blue, and blue to red
* Clay Shirky <clay.shirky@nyu.edu>
*/


int redPin   = 9;   // Red LED,   connected to digital pin 9
int greenPin = 10;  // Green LED, connected to digital pin 10
int bluePin  = 11;  // Blue LED,  connected to digital pin 11

// Program variables
int redVal   = 255; // Variables to store the values to send to the pins
int greenVal = 1;   // Initial values are Red full, Green and Blue off
int blueVal  = 1;

int i = 0;     // Loop counter
int wait = 50; // 50ms (.05 second) delay; shorten for faster fades

void setup()
{
  pinMode(redPin,   OUTPUT);   // sets the pins as output
  pinMode(greenPin, OUTPUT);
  pinMode(bluePin,  OUTPUT);
}

// Main program
void loop()
{
  i += 1;      // Increment counter
  if (i < 255) // First phase of fades
  {
    redVal   -= 1; // Red down
    greenVal += 1; // Green up
    blueVal   = 1; // Blue low
  }
  else if (i < 509) // Second phase of fades
  {
    redVal    = 1; // Red low
    greenVal -= 1; // Green down
    blueVal  += 1; // Blue up
  }
  else if (i < 763) // Third phase of fades
  {
    redVal  += 1; // Red up
    greenVal = 1; // Green low
    blueVal -= 1; // Blue down
  }
  else // Re-set the counter, and start the fades again
  {
    i = 1;
  }

  analogWrite(redPin,   redVal);   // Write current values to LED pins
  analogWrite(greenPin, greenVal);
  analogWrite(bluePin,  blueVal);
}