We filled up a Peggy 2 with 2×2 super-pixels consisting of red, green, blue, and white 10 mm LEDs. This makes an easy and big programmable full-color LED matrix.
And like whoa– you can animate it.
Yup, there’s video. The video is embedded below, and you can also view it directly at YouTube. (In either case, please excuse the scanline artifacts produced by our camera.)
One thing worth noting (and that we demo in the video) is that you can diffuse the big RGBW pixels into one continuous full-color display by placing a thin diffusing plastic layer above the LEDs– it really works well.
The demo code is an Arduino sketch, based on Jay Clegg’s timer-interrupt style grayscale driver for Peggy (demonstrated here), you can download it here (12 kB Arduino .pde sketch file). Besides the colorful flow shown in the pictures, this code also has a mode to light just the red, green, blue or white LEDs at a time.