If you are curious as to the status of my project. I am still awaiting parts, the BeagleBone Black and the majority of the parts have not arrived -- Currently, I have been testing physical prototypes of the plectrum itself. I have decided, mainly due to limited availability of parts on hand to try a conductive based approach.
The plectrum will be constructed as a sandwich... No, not a cheese and onion sandwich but rather a construction of conductor -> insulator -> conductor. Both conductors will be fed to an amplification circuit to detect conduction to a steel string common return, possibly ground on the audio pickup jack of an electric guitar.
I will have to test the conductivity between the contact point and string, but a simple amplifier should ensure that even higher levels of resistance could create an appropriate trigger level for the BBB controller :
On my next blog post, I will connect up the plectrum prototype to a microcontroller, that I have on hand (possibly not the BBB) for further processing.