Re: [LAU] GPIO to alsa

From: Christopher Arndt <chris@email-addr-hidden>
Date: Sun Feb 28 2016 - 16:45:28 EET

Am 28.02.2016 um 13:18 schrieb Raphaël Mouneyres:
> Is there a existing project which would scan rows/colums of a keyboard from the designated(configured) gpios, and throw midi message to an alsa midi port ?

Such a software would have to vary according to the keyboard model, the
available GPIO ports and the extra electronic components used (e.g.
shift registers or de-multiplexers).

A general purpose operating system like Linux is not best suited for
such an application, since the scanning rate should be in the
sub-millisecond range to get a good velocity resolution (assuming you
have a keyboard with two contacts per key).

A project that generally does what you want is midibox. It's an OS for
electronic musical devices, which runs on STM32F4 discovery boards (ARM
Cortex M4 processor) and has keyboard matrix scanning facilities build
in. You can attach DIN MIDI in- and outputs or use it as a USB-MIDI
client via the micro-USB connector of the discovery board or even have
it send OSC via ethernet.

http://ucapps.de/midibox_ng.html
http://ucapps.de/mbhp_core_stm32f4.html
http://ucapps.de/mbhp_dio_matrix.html

Chris

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Received on Sun Feb 28 20:15:02 2016

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