Will we be able to sense color from an RGB LED like we can sense light reflected of different colors?
Think the light is definitely different as a LED peaks in three wavelengths and the light of the sun is "broadband". Further you need somthing to diffuse it (sugarcube?)
How do you intend to measure the different colors? a special device ? - http://www.sparkfun.com/products/8618
- or three LDR's with a filterglass. The latter offers more room for experimentation as they can use anything semi-transparant as colorfilter, or include polaroid filters.
The closed loop is interesting if you program a delay in it and 'rotate' the colors (red->yellow->blue->red) or so.
sofar my 2 cents,