So. i want to turn my raspberry pi 3b+ into a bass pedal.
i’ve never made any electronic projects nor soldered anything
my idea that probabbly wont work
the incredibly simple solution would’ve been to
Atttach a button to the pi
use MrsWatson (it’s on github) and use microphone file as an input and the speakers as an output file (i think they are called file descriptors).
mrsWatson can proces input through a “effect” file (.vst) so i would like to make a script that detects that the button was pressed and switch the .vst file to the next one
do all the sound input and output though the pi’s integrated audio jack
since i have no idea about electronic i want to add: my bass is an active bass. i don’t know if that makes a difference
my problem
i’ve been trying to do this on my pc before starting with the pi and making the horrendous cable that i would need for this project
so far i have had no success using cat to read mic and ‘>’ to pass it to the headphones. mainly because i couldn’t find the files themselves, but i’ve also read that using cat on a mic is not as easy as it sounds (no pun intended)
another option would be to use jack for input output mapping. but i don’t think i would be able to pass that to MrsWatson
To be honest:
Don’t bother. In your usecase, it’s all about latency. And neither a Raspberry PI, nor almost any standard Soundcard will be able to push the monitoring latency to sub 10ms.
At the very least, you’d have to use a USB Soundcard like this or similar.
You can’t use MrsWatson like you want to either. It only is made for changing recorded audio from files. It’s not optimized for latency in any way.
So, even if you could make it work, you’d hear yourself half a second after playing a note.
Considering all this, it’s probably easier and cheaper (any maybe more fun) to just build the pedals you want. DIY’ing Effects Pedals is really easy, accesible and there’s a great community around it. If you’re willing to skimp on the case a bit, you can build Tubescreamers for around 10 bucks, and a bunch of other stuff for not much more.
I agree that latency is going be a pain with a rpi. You would usually want to program a dsp chip that is meant for low latency operation. If you want play with the pi just for the lolz, this might give some inspiration https://www.electrosmash.com/pedal-pi
This doesn’t really sound like a pie problem.
I guess you can make some input/output alteration of sound, but using a CPU for this seems like overkill, and would introduce a world of problems.
But yes you can distort sound incomming, and outgoing.
if you wan’t to create a embedded’ish type of OS for a pedal, look into Yocto, they have releases for raspberry pie, and are about as embedded’ish as you get using linux.
Absolutely. Theres expansions that add multiple audio jacks on the gpio pins or you could make a bread board with a DAC and 2 quarter inch jacks. My worry would be is there enough power in a pi to drive the dac, or would it need an amplified powersource.
You could absolutely do it though. I’d be keen to see what you produce.