I'd been thinking about this idea for a long time now, how to build a color changing saber out of my first custom saber featuring a NB v1.0 (entry level electronics, well, compared to Hasbro, a NB is a formidable toy!).
At first my saber had one color. Then I made 2 connectors for my Cree XP-E RGrB module (red, green, royal blue) to be able to switch on 2 Colors at a time. For 3 connectors I did not have the space, and moreover it was not "dedicated" enough. I wanted to have real color mixing, not just switching. And then...

... I made it at last: a self-developed "color mixing engine" hooked to a NB v1.0. This little piece of electronics can mix the 3 base colors to get (theoretically) any color out of it, and it's close to be true in fact. It's also not magic, basically you need only a few components and it can be crammed into the hilt along with the NB.

What I like about it is the fact that it's totally in the spirit of Star Wars, a science-fiction world where all technical problems can be solved by a screwdriver and/or a well placed hit of a wench/hammer/whatever comes handy.

Here is a pic of the hilt (mix of TCSS and parts from other vendors, actually I picked one of the hilts I have , I still did not decide which of them will get this combo) and the chassis:


Basically the idea is simple: I have 3 potentiometers controlling the gate voltage of 3 p-channel MOSFET's in a low-side driver configuration, which turns them into variable resistances, which are capable of delivering power to the individual LED's. By turning the potmeters with a screwdriver, I can mix the 3 Color in any combination and hue (I was insired by the cut-out scene from the Return of the Jedi, where Luke made final adjustments to his new green lightsaber with a screwdriver before setting out to Jabba's Palace). I will in the next days make some sketches of the schematics so that it becomes more clear what I mean. I also devised 2 different ways to do it:
- for setups needing more than the 2A spec'd for NB a bypass-technique
- for standard setups staying below 2A an integrated one

This is a pic of some of my favorite colors I mixed out:


I also made a (maybe not so) short video to show how it works. Sorry for the coughing, last weekend the weather around here was rather Hoth and I caught a bad kind of flue.