Control your Emacs with an accordion — or any MIDI instrument!

A video demo is coming soon… meanwhile, see https://twitter.com/ykarikos/status/1038145486618861573

You only need a computer running Linux or BSD with OSS (or ALSA emulation of OSS), some MIDI instrument, and Emacs (version 24.3 or later - for cl-lib).

You can e.g. plug in a MIDI pedalboard (like one in a church organ) for modifier keys (ctrl, alt, shift); or you can define chords to trigger complex commands or macros.

2018-09-11, version 0.0.9.

Connect the MIDI instrument.

Modify the emaccordion.el file as follows.

Make sure the emaccordion-midi-device-pathname points to the correct OSS midi device.

If you want some of your MIDI instrument keys to behave like control, meta, shift, hyper, super or alt keys, modify the table emaccordion-note-to-modifier. Edit that to suit your purposes. This is a list containing a mapping from MIDI channel and note to a modifier. The possible modifiers are :alt (which is probably not what your keyboard’s “Alt” issues), :super, :hyper, :shift, :ctrl and :meta (which is typically keyboard’s “Alt”).

Matching chords to characters or macros or functions is configured with emaccordion-chord-actions, so edit that to your liking. Chords (which can also be just one note) are defined as a list of MIDI channel and note. Action can be:

1. a character in Emacs format (e.g. ?a for lowercase a, or ?✈ for Unicode airplane character) to input that character
2. anything that satisfies functionp and commandp (e.g. interactive function like emacs-uptime)
3. vector or a string, see execute-kbd-macro

If a MIDI key has both a modifier and a chord definition, the modifier key definition takes precedence. Hence, chords with that key will not work as intended.

Emaccordion is still under construction, so the configuration isn’t as user-friendly as it should be. This should be improved.

Load the emaccordion.el you modified. Start the MIDI reader process by calling emaccordion-create-midi-reading-process. Then just start typing.

The buffer *emaccordion-events* is updated with received events. This may help with troubleshooting.

See file documentation.org for a more thorough technical exposition.

The idea for the whole thing came from EmacsWiki: https://www.emacswiki.org/emacs/EmacsMidi. I immediately became totally convinced that a full-size chromatic button accordion with its 120 bass keys and around 64 treble keys would be the epitome of an input device for Emacs.

The video has been inspired by Yuri Charyguine’s awesome Moscow Nights: https://www.youtube.com/watch?v=ajUtVyGv7ss. The video also refers to “Emacs Rocks!” series by Magnar Sveen, which I highly recommend: http://emacsrocks.com/

There’s another Emacs MIDI library, written by David Kastrup: https://elpa.gnu.org/packages/midi-kbd.html.

Here’s a brief list of what needs to be improved.

• Implement the various user-configurable parameters with defcustom.

Janne Nykopp <[email protected]>

GNU General Public License Version 3, 29 June 2007