I'm using a Pi to drive a Fadecandy board to light up a varying-length string of RGB LEDs in different, pulsating colors. I've been successful, however one snag I ran into along the way was programmatically defining the LED colors in RGB.
I copied the Fadecandy example program measuringstick.py (which makes every 10th LED green and the rest white) and tweaked it to create a rainbow of colors instead. Wrote the program into /etc/rc.local, rebooted the Pi, and noticed that my colors were completely off! After a half hour of messing around, I realized that defining the colors in GRB instead of RGB gave the correct result. In other words, if I want an LED to be bright red I have to define its color as (0,255,0) instead of (255,0,0).
Is this a normal thing with LED pixels? All of the example code was written in RGB, so I assume that GRB is not normal. Can someone explain to me what's going on? I'm more curious than anything at this point.
(Sorry I don't have any code to show you. My collaborator has the lights/Pi with him today)