Tod Kurtz's "picotouch_bizard" Is a Business Card-Sized Pressure-Sensitive MIDI Controller

Powered by a Raspberry Pi Pico mounted on the rear, this compact card delivers pressure-sensitive MIDI control with no moving parts.

Embedded developer and self-described "multi geek" Tod Kurt has built a pocket-size MIDI controller in the footprint of a business card, powered by a low-cost Raspberry Pi Pico mounted on the rear — and delivering pressure-sensitive controls with no moving parts.

"I made a business card MIDI controller," Kurt explains of his latest project. "Captouch [capacitive touch] pads with LED backlighting and even a rudimentary pressure sensitivity (that does the mod wheel)."

This business card sized board delivers pressure-sensitive MIDI control in a compact footprint — with no moving parts. (📷: Tod Kurt)

The project is a spin-off of Kurt's earlier "picoslidertoy," which was likewise powered by a Raspberry Pi Pico. This time, though, there are no slider-style controls to be found; instead, the business card footprint board has eight primary buttons and three user interface buttons, all using capacitive touch controls, designed to deliver MIDI control in a tiny footprint.

"It has normal MIDI out as well [as USB]," Kurt explains of the device's capabilities, "[and] also has pressure sensitivity" — allowing for variable control of MIDI settings by simply pressing down harder, despite the total lack of any moving parts in the card's design.

The board is programmed in CircuitPython, with the source code for a function-test program and the MIDI controller firmware published to GitHub under the reciprocal GNU General Public License 3; a KiCad project for the board is available from the same repository.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire:
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