This is a marvel, well done Thexter! Definitely impressive and sounds like a real saber.
When I looked at your first demo video a while back my first though was: heck, this is how native swings/swirls sounds like, which apart from the fact that it sounds insanely authentic has an additional charm that one does not need any special sound files for swings and some other effects which are perfectly substituted by the pitch shifted hum. And - not to underestimate - the sheer amount of code to detect swings and even more complicated gestures like swirls will be reduced as well.
I was in fact so impressed that it gave me just the right kick to embark on a new journey I had been contemplating on starting for a long time. For my boards I wanted to have a more powerful processor, but I kept delaying the project because most saber FX's can be done with an 8-bit AVR. Then I saw this. I spend the last couple of weeks to breadboard a new system, same peripherials, except that instead of a 8-bit AVR now I have a 32-bit processor, and skip the MP3 chip because I can play the sounds from the processor. It's fun!!!
I'm for sure far away from the refined algorithm you must have programmed to make the pitch shift such smooth...at the moment I can play the music, I can even reloop hum gaplessly and interrupt it with clashes. So more or less the ground work is done to thrust into the heart of things. I made a simple sketch to change the playback sample rate simply by the max of the acceleration values from the MPU and I can get pitch shifting... well, sort, but I somehow have the feeling that the acceleration is not the right measurement to base the pitch shift on ... so now I try to base it on velocity instead. Of course any hint to the community is highly welcome. I think I need to find a way to eliminate the gravity...
Thanks a lot and salute to you for driving the open source / programmable saber board solution community!!! Outstanding work!