So, as the project is currently using the Mozzi audio library, which seems to be available under the Creative Commons 4.0 Share Alike Non-Commercial License, I am sharing the source code on GitHub. In addition, all of the PCB files are available too, although they don't yet include all of the bodges I had to make in order to get them to work.

I suppose anybody could build their own then. Open source and all that.

I actually have quite mixed feelings about that. 

I know we are supposed to be all "Rah! Rah! Open Source Forever!" on here, but I am really hoping to sell these eventually, as I've been running a deficit for the last 10+ years. My Nintendo DSi/3DS software "Rhythm Core Alpha 1 & 2" never did earn me anything resembling a proper living, they just slowed the hemorrhaging of  money a bit. It wouldn't be fun if it became popular and everybody knocked it off. But I suppose there are lots of other synth projects out there that are open-source that most folks don't bother to build, so perhaps my worries are groundless.

Although, I have to say, I have made it REALLY EASY to build... 

I'll have to rewrite all of the Mozzi bits if I want to actually sell any of them; I'm using it for now to get the contest entry done, and it will probably survive through the MAGwest 2019 version; they are a 501c3 and so count as non-commercial, I think.

The code has not been beautified for public consumption, but I have fulfilled the terms of the license,.

Anyway, you can look upon my works and be dismayed here:
Stylish! Trucker Belt Synthesizer on GitHub