So, the process would look like:
Bass In-Pitch Detection-Bass Out
With the output of the pitch detection being Midi?

You are aware that
a) This would almost certainly be monophonic. (The string sound wouldn’t, but you couldn’t play a chord on the bass)
b) It would require substantial tweaking of the synth to get an acceptable sound.

I don’t think a circuit in a nano body would be able to overcome these limitations, but the POG can do almost perfect polyphonic tracking, so there may be hope for you.

What I would recommend, however, is shelling out a hundred odd dollars for a Roland MIDI pickup. That way, you can plug directly into your synth.

Hey, it was just a suggestion. If you really want PERFECT synth tracking, midi pickups are the only way to go. And trust me, they don’t interfere with tone at all. But, since you’re obviously not open to that, don’t take my word for it.

The reference to the POG was merely that the requisite technology exists. I wasn’t suggesting one.

What I’d suggest you do is do some research yourself.

Of course, the best and most baddass way around the problem is to do a Geddy Lee and play bass and keys at the same time.