[linux-audio-dev] Software controller for homemade edrums

[Olivier Guilyardi]

Hi,

Assembling piezo microphones, cardboard, foam, wood and a cymbal stand, 
I have just made my first DIY electronic pads. Actually it's electronic 
percussions, because I will play these mostly with hands.

I've found a few sites about DIY "edrums" (1), as well as some detailed 
documentation about how to build a trigger-to-midi hardware controller 
(2). But since I started this little project, I've been thinking about 
plugging the piezo mikes directly into my soundcard inputs. My first 
tests are very good :  the signal is clean, and indicates faithfully how 
hard the pads get hit.

I am now about to code a software controller to  :
1 - either interprete the signal and produce midi (or OSC) events
2 - or interprete the signal, and play samples by itself, in a 
standalone manner (no midi)

I tend to prefer the second option, for the following reasons (criticism 
welcome) :

- I want to reduce latency _as_much_as_possible_ (keeping the rythm is 
hard enough ;-). To me, the midi layer introduces useless buffers

- I'd like the whole thing to use minimal resources, so that I can run 
it on old hardware (simple boxes to be carried in studios and on stage). 
In this regard, a small tool built upon Alsa, which run without any 
sound server or midi layer, looks to me as the lightest solution

- I don't want to use harware expanders, such as the one that is built 
into my soundcard. I want to play samples. With midi, I would then need 
a such tool as Timidity, which is pretty heavy according to my latest 
tests. Jtrigger seems lighter (http://sparked.zadzmo.org/jtrigger), but 
it relies on Jack : I like Jack, but it seems too heavy to me, for this 
specific job.

- In regard to clicks and other noises, I believe a lightweight 
application running on a dedicated barebone Linux system is more 
reliable than a realtime thread with a complex layer as Jack, especially 
on slow hardware.

Are these good/coherent reasons to you ? Do you have any other advice ? 
Is there already some software that could help me, or some pieces I 
could reuse, to achieve any part of this process ?

Best regards

References :
(1) http://edrum.for.free.fr
(2) http://www.midibox.org/edrum

--
  og