Twitter Mood Light - The World's Mood in a Box

Step 10 Programming step 4: RGB LED

A simple library for setting the colour of an RGB LED. The library will fade between the colours as the world mood changes, and will flash if it is a significant change in mood.


*** update ***

If you find the colours look wrong, try removing the "255 -" from the analogWrite calls.
Thanks to shobley for finding this.
More info at http://www.stephenhobley.com/blog/2010/06/11/arduino-world-mood-light-using-twitter-and-wishield/

*** end update ***

/*

 The led is initially set to be currentColorID and over time will fade

 to desiredColorID with a time delay, fadeDelay, measured in ms, between

 each step. No effort is made to scale the step size for each rgb

 channel so each may not complete at the same time.

*/

void LED::FadeTo(int desiredColorID)

{

      // check for valid colorID

 if (desiredColorID >= NUM_COLORS ||

      desiredColorID < 0)

    {

      //logger.log("invalid Color id")

      return;

    }

   

 // get a local copy of the colors

 Color currentColor;

 currentColor.r = Colors[m_currentColorID].r;

 currentColor.g = Colors[m_currentColorID].g;

 currentColor.b = Colors[m_currentColorID].b;

 

 Color desiredColor;

 desiredColor.r = Colors[desiredColorID].r;

 desiredColor.g = Colors[desiredColorID].g;

 desiredColor.b = Colors[desiredColorID].b;

 

 bool done = false;

 

 while (!done)

 {

    // move each of r,g,b a step closer to the desiredColor value

   

    if (currentColor.r < desiredColor.r)

    {

      currentColor.r++;

    }

    else if (currentColor.r > desiredColor.r)

    {

      currentColor.r--;

    }

   

    if (currentColor.g < desiredColor.g)

    {

      currentColor.g++;

    }

    else if (currentColor.g > desiredColor.g)

    {

      currentColor.g--;

    }

   

    if (currentColor.b < desiredColor.b)

    {

      currentColor.b++;

    }

    else if (currentColor.b > desiredColor.b)

    {

      currentColor.b--;

    }

 

    // write the new rgb values to the correct pins

    analogWrite(m_redPin, 255 - currentColor.r);  

    analogWrite(m_greenPin, 255 - currentColor.g);

    analogWrite(m_bluePin, 255 - currentColor.b);  

   

    // hold at this color for this many ms

    delay(m_fadeDelay);

   

    // done when we have reach desiredColor 

    done = (currentColor.r == desiredColor.r &&

            currentColor.g == desiredColor.g &&

            currentColor.b == desiredColor.b);

           

 } // while (!done)

 

 m_currentColorID = desiredColorID;

}