build your own

MIDI-64

A USB MIDI controller with four pages of CCs, built around an Arduino Pro Micro and a 16-channel mux. Buy the parts below, wire it up from the schematic, flash the firmware, and it shows up as a standard MIDI device.

parts list schematic
Render of the MIDI-64: a black enclosure with a grid of knobs, two buttons and four red LEDs

01 parts

16×
Rotary potentiometer, 1 kΩ linear WH148 B1K, 3-pin, 15 mm shaft. One per knob.
₹20 each₹320 makerbazar
1×
Arduino Pro Micro, USB-C ATmega32U4, so it can be a native USB MIDI device.
₹539 robu
1×
CD74HC4067 16-channel mux breakout Lets one analog pin read all 16 pots.
₹49 robu
2×
16 mm momentary push button R13-507, 2-pin, self-reset. Bank and channel.
₹29 each₹58 robu
4×
3 mm red LED Page and channel display. Sold as a pack of 50.
₹0.50 each₹25 for the pack robu
4×
1 kΩ resistor ¼ W, one in series with each LED. Any electronics shop.
—
ElectronicsPlus four resistors and some hookup wire.
₹991
1×
Front panel Laser cut from midi twister v18 - top.dxf.
in total below
paper crane lab robu
1×
Back panel Laser cut from midi twister v13 - bottom.dxf.
in total below
paper crane lab robu
1×
Side panel 3D printed from side_panel.stl.
in total below
robu
EnclosureApproximate, depends on material and where you order.
~₹800
Whole buildElectronics plus enclosure.
~₹1,800

You'll also need hookup wire, solder and a USB-C cable. The panel files are in the hardware folder. Not sure where to shop? See the components buying guide.

02 wiring

fromto Pro Micro
Pot wipers 1–16mux C0–C15 (outer legs to VCC and GND)
Mux SIG (common)D6 / A7
Mux S0, S1, S2, S3A0, A1, A2, A3
Mux ENGND
Mux VCC, GNDVCC, GND
LEDs 1–4, each via 1 kΩD3, D5, D9, D10 (cathodes to GND)
Bank buttonD4, other leg to GND
Channel buttonD7, other leg to GND

03 build files

pdf

Schematic

The whole circuit on one page: Pro Micro, mux, LEDs and buttons.

open schematic

dxf · stl

Hardware & enclosure

Top and bottom plates as DXF for laser cutting, the side panel as STL for 3D printing, plus footprints and mockups.

open hardware

arduino

Firmware

MIDI64.ino and the Arduino board files. Needs the MIDIUSB library; upload it to the Pro Micro over USB.

open firmware

readme

Using it

Page and CC assignments, channel mode, the LED codes and how knob pickup works.

open docs