OK so we talked about this project a bit in the “simple DSP inside Core Module?” thread, but I wanted to give an overview here.
The plan is to build a guitar-like midi controller for use with midi synthesizers. The strings of the guitar will be essentially ribbon controllers with vhs tape glued to a fretless guitar neck. From these circuits I will extract a pitch value and either quantize it and apply it at note-on or turn it into a cc to be applied to the synth’s pitch bend parameter. Other, more exotic uses could probably be tested with ease once I have built it.
The strings will run over graphtech ghost bridge saddles which also act as individual pickups. (If anyone knows of a less expensive polyphonic pickup system, let me know. They are $100) Each string’s amplitude will be converted by some means into midi-cc values, with the intent to apply these to a synth’s volume parameter.
I have some experience in analog electronics and some c programming, but am new to pics and designing midi controllers, so I appreciate any input you guys have.
You might want to consider looking at the Hagstrom guitar synth approach. That utilised the strings and frets as a keyboard matrix. Each string was isolated, and the frets were wired into a matrix. That way, when the string was pushed onto the fret, it produced a discrete voltage. Obviously this doesn’t allow for pitch bend, but it is fast (keyboard fast) and very reliable. It would also allow you to use standard pickups and regular magnetic strings. In fact, it would play just like a real guitar, except that it’s not necessary to pluck the strings, just to fret them, to get the sound. I don’t know if you’ve seen it, but the Stepp guitar synth used a similar detection method, with gate signals derived from a seperate set of strings, so maybe that could be a possibility if you use piezos as triggers.
the (diode) matrix approach would work polyphonically. the frets can be in one piece, just you´d need to find a way to have the strings insulated from each other.
which has been the inspiration for my own guitar-like ribbon controller instrument, still unrealised four years later… man, what have I been wasting my time on?
In the opening post I mentioned the graph tech ghost bridge saddle pickups. They are bridge saddles with piezo elements mounted inside. These were designed with hex output in mind, so I imagine that they would get good individual output with minimal crosstalk.
I bet you’re right about the wearing down of the resistive element. Maybe there are more robust resistive materials than vcr tape? Antistatic packaging is supposed to have resistive qualities. But that’s also just plastic.
I’m sure the companies that make slider pots would know about robust resistive strips.
Here’s a question: What value pots are suggested for use with the ain module? What values are allowable?
I’m sure the companies that make slider pots would know about robust resistive strips.
… the company where I work was building their faders by themselfe a few years ago. - The biggest issue was the design of the sliding piece in matter of wearing down the taper vs. cleaning it (scrape away the dirt without wearing down the conductive plastic). - So … no chance :-[
