An attempt to make a synth that is playable like a guitar, based around the Seed:
A work still in progress, but i have most of the hardware bugs sorted out, the main focus now is adapting carlvp’s Op6 engine. The idea is that the ‘sysex’ information that defines a particular FM sound configuration will be held on a cartridge (EEPROM or FRAM via I2C interface to the Seed) which plugs into the guitar - going for an 80s vibe.
Quite interesting, thanks for sharing. If I understand this, the strings are only used to set the amplitude envelope. I am curious if it would be possible to use the strings for both pitch and amplitude instead of having separate controls.
As a side note, I have the sonuus G2M controller (sonuus - Music Products Designed in the UK), but the latency is so bad and inconsistent, it is no usable in any live situation.
This is awesome!! Looks like a blast to play 
Using the string for amplitude is a great idea!
Similar to @KnightHill, I have also wondered about being able to control the pitch with the string as well.
Been meaning to test it out personally too but I’m guessing the string is a bit too thick for the capacitive sensor to detect.
Anyway, I’m looking forward to seeing more of this project in action!
Thanks for your interest @Takumi_Ogata and @KnightHill , it would of course be simpler and somewhat more intuitive control-wise (for a guitarist) to use the string for both. I had considered it at the beginning. To implement this you basically have two options, 1) do pitch detection with the pickups (no softpots) via signal processing, or 2) press the string down to the softpot i.e. position the softpot under the string. For option 1), I believe pitch detection with guitar pickups is unreliable and prone to latency issues (I might be wrong), and for option 2), when fingering a string onto a softer surface like a plastic softpot, you lose much of the sustain, especially at the higher end. These issues are why I decided to ‘split out’ pitch and amplitude (at the cost of losing 4 strings due to space considerations!).
I’d be keen to hear other peoples’ thoughts and experiences on this.
Cheers
I agree that 6-string pitch detection is very hard. However, have you considered using hexaphonic pickups like the one below?
https://reverb.com/uk/item/13678507-shadow-sh-075-hexaphonic-midi-pickup
I’m actually using a dual single-coil pickup made by Paul Rubenstein at Ubertar, so I have a separate signal from the two strings. It might be worth doing some experimentation with some FFT code (or something) to see whether it’s practical.