Fading Arduino RGB LED from one color to the other?

Question

I\'ve currently managed to get my LED to cycle through eight colors that I\'ve selected. Everything is working correctly, except that I want to go for a more natural feel, and w

Answer 1

You can simplify your code by using a struct for your color.

struct Color
{
    unsigned char r;
    unsigned char g;
    unsigned char b;
};

Then, it is easy to have a fading function

// the old color will be modified, hence it is not given as reference
void fade(Color old, const Color& newColor)
{
    // get the direction of increment first (count up or down)
    // each of the inc_x will be either 1 or -1
    char inc_r = (newColor.r - old.r)/abs(newColor.r-old.r); // note, that the right hand side will be sign extended to int according to the standard.
    char inc_g = (newColor.g - old.g)/abs(newColor.g-old.g);
    char inc_b = (newColor.g - old.g)/abs(newColor.g-old.g);

    fadeOneColor(old.r, newColor.r, inc_r, old);
    fadeOneColor(old.g, newColor.g, inc_g, old);
    fadeOneColor(old.b, newColor.b, inc_b, old);
}

void fadeOneColor( unsigned char& col_old, 
                   const unsigned char& col_new, 
                   const char inc, 
                   Color& col)
{
    while(col_old != col_new)
    {
        col_old += inc;
        SetColor(col); 
        delay(20);
    }        
}