This project was underway before I actually was on Hackaday.io, so a quick summary of where things stand:

-The PCB seems to be functional. It milled just fine and there weren't any assembly issues.

-The software is at a rough prototype stage. It has a very basic technique for determining the pitch of a note being played, but is somewhat inaccurate. This is likely due in part to the limited FFT size (there's only 8k of RAM), and in part due to no filtering being done. One next step on the software side is to do some averaging of a couple FFTs before reporting a pitch.

-The enclosure design is looking good. The GCode needs some slight tweaks (there are some burrs on the hinge that should be taken off, and the lid needs to be milled yet), and a slot needs to be milled to accommodate the USB port, but otherwise the PCB seems to fit.

Still to-do:

-Mill the lid (GCode and actual milling)

-Tweak software for better performance

-Get a battery

-Assemble the whole thing (drill hinge, put PCB in enclosure, and add the battery)

-Publish code and whatnot

Oh, and I evidently need more updates (which should come with more progress), and a video (which will actually take work).