C i b o M a h t o . c o m

You might remember that some years ago, I found a discarded organ and brought it home. Well, it sat around for a year, then I converted it to MIDI, then I moved across the country and only brought the keyboards, and finally I re-built it as the proper single-row unit featured in the above video.

The keys are laid out as a generic matrix-style keyboard, with a column for every note in an octave (12 in total), and a row for each octave bank (up to ten, although only 8 are in use). Using a Barebones Arduino clone and a couple of I/O expander chips (PCF854AN) for extra digital pins, I was able to convert the old keyboard into a MIDI device. This version works fine, however the circuit is a bit extravagant- If I ever re-build it, I will use a 3-to-8 line decoder for the select lines, which should free up enough digital pins on the Arduino to be able to get rid of the I/O expander chips. Really, though, I would prefer to convert it into a velocity sensitive keyboard, so any further effort will be in that direction. Rough schematic and source code after the break.

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