µMODULAR
µMODULAR is an open-source toolkit for building custom MIDI controllers and instruments. It provides a KiCad schematic library (lib/) of reusable hardware building blocks and a set of tested PCB modules (v1/) that you can build, combine, and expand.
- License: CC-BY-SA 4.0
- Repository: github.com/midilab/uMODULAR
- Website: midilab.co/umodular
lib/ — KiCad Schematic Library
The lib/ directory contains KiCad schematic modules (.sch) and PDF reference sheets that serve as reusable building blocks. Open the combined project umodular_libs.kicad_pcb in KiCad to mix and match these modules into your own custom PCB designs.
| Module | Description | Files |
|---|---|---|
| POT8 | 8× potentiometer input (multiplexed) | pot8.sch, pot8.pdf |
| POT16 | 16× potentiometer input (multiplexed) | pot16.sch, pot16.pdf |
| PUSH8 | 8× button + LED matrix | push8.sch, push8.pdf |
| PUSH16 | 16× button + LED matrix | push16.sch, push16.pdf |
| LED8 | 8× LED output | led8.sch, led8.pdf |
| LED16 | 16× LED output | led16.sch, led16.pdf |
| MIDI | MIDI I/O (5V) | midi.sch |
| midi-io-5v | MIDI interface reference | midi-io-5v.pdf |
An overview schematic (overview.pdf) shows how the modules interconnect.
To use: clone the repo, open lib/umodular_libs.kicad_pcb in KiCad, copy the desired schematic sheets into your project, and wire them to your microcontroller.
v1/ — First Generation PCB Modules
These are ready-to-build PCBs designed using lib/ schematics. Each module connects to an Arduino-based shield via ribbon cable headers.
Arduino Mega Shield
Base shield compatible with Arduino Mega, Micro, and Mini 5V boards. Provides power distribution, MIDI interface, and expansion headers for all µMODULAR modules.
Dimensions: fits Arduino Mega form factor
BOM
ICs
- 1× 23LC1024-I/P
- 1× 74HC4050
- 1× 6N138
- 1× Socket 16P DUAL WIPE
- 2× Socket 08P DUAL WIPE
Capacitors
- 2× 50V 100nf (.1uF) ceramic disc
Resistors (1/4W)
- 3× 220Ω
- 1× 1kΩ
- 1× 2.2kΩ
- 1× 4.7kΩ
- 2× 10kΩ
Diodes
- 1× 1N4148
Connectors
- 2× Circular DIN 5P R/A PCB shielded (MIDI)
- 12× 05+05 DIL vertical pin header
- 1× 18+18 DIL vertical pin header
- 5× 08 SIL vertical pin header
- 1× 06 SIL vertical pin header
- 1× 02 SIL vertical pin header
CTRL16
10cm × 12.5cm PCB module with 16 potentiometers and 8 buttons with LEDs.
BOM
Buttons & LEDs
- 8× Tactile switch 6.0×4.3mm 160g
- 8× Through-hole diffused T-1 (3mm) LED
Potentiometers
- 16× 10K linear 20% (Bourns PTV09A-4015F-B103)
ICs
- 2× CD4051BE
- 1× 74HC595N
- 1× 74HC165N
- 4× Socket 16P DUAL WIPE
Capacitors
- 4× 50V 100nf (.1uF) ceramic disc
Resistors (1/4W)
- 8× 220Ω
- 9× 10kΩ
Headers
- 4× 05+05 DIL vertical pin header
Cable connection
- Ribbon cable 10 conductors 28 AWG .050 (length to suit)
- 8× Female ribbon cable header 10 pos, 2 rows, 2.54mm pitch
MIDI4
10cm × 2.5cm PCB module with 2 MIDI In and 2 MIDI Out ports.
BOM
Connectors
- 4× Circular DIN 5P R/A PCB shielded
ICs
- 2× 6N138
- 2× Socket 08P DUAL WIPE
Resistors (1/4W)
- 2× 4.7kΩ
- 6× 220Ω
- 2× 1kΩ
Diodes
- 2× 1N4148
Headers
- 1× 05+05 DIL vertical pin header
Cable connection
- Ribbon cable 10 conductors 28 AWG .050
- 2× Female ribbon cable header 10 pos, 2 rows, 2.54mm pitch
MIX4
10cm × 12.5cm PCB module with 4 slide faders, 4 potentiometers, and 8 buttons with LEDs.
BOM
Buttons & LEDs
- 8× Tactile switch 6.0×4.3mm 160g
- 8× Through-hole diffused T-1 (3mm) LED
Potentiometers
- 4× 10K linear 20% (Bourns PTV09A-4015F-B103)
- 4× Slide 60mm stroke, single linear (Bourns PTA6043-2015DPB103)
ICs
- 1× CD4051BE
- 1× 74HC595N
- 1× 74HC165N
- 3× Socket 16P DUAL WIPE
Capacitors
- 3× 50V 100nf (.1uF) ceramic disc
Resistors (1/4W)
- 8× 220Ω
- 9× 10kΩ
Headers
- 3× 05+05 DIL vertical pin header
Cable connection
- Ribbon cable 10 conductors 28 AWG .050
- 6× Female ribbon cable header 10 pos, 2 rows, 2.54mm pitch
POT16
10cm × 10cm PCB module with 16 potentiometers.
BOM
Potentiometers
- 16× 10K linear 20% (Bourns PTV09A-4015F-B103)
ICs
- 2× CD4051BE
- 2× Socket 16P DUAL WIPE
Capacitors
- 2× 50V 100nf (.1uF) ceramic disc
Headers
- 2× 05+05 DIL vertical pin header
Cable connection
- Ribbon cable 10 conductors 28 AWG .050
- 4× Female ribbon cable header 10 pos, 2 rows, 2.54mm pitch
Firmware Libraries
µMODULAR hardware pairs with two firmware libraries built for Arduino (PlatformIO):
- µClock — BPM-accurate clock generator using hardware interrupts
- µCtrl — Driver layer and UI framework for all µMODULAR modules
Both support AVR (ATmega168/328/16u4/32u4/2560) and ARM (ESP32, SAMD21, Teensy) architectures.
Applications
Real-world projects built with µMODULAR:
- Aciduino V2 — 16-track Roland-inspired step sequencer
- Atari 2600 MIDI Station — Live sequencer and MIDI controller
- Oberheim Matrix Controller — Commercial controller with arpeggiator (by Alpes Machines)
- Various community projects: gesture sequencers, drum synths, looper pedals
Getting Started
- Clone the repository:
git clone https://github.com/midilab/uMODULAR.git - Browse
lib/for schematics orv1/for ready-to-build PCBs - Order PCBs from your favorite fab house using the Gerber files
- Pair with µClock and µCtrl firmware
- Join the Discord community for help and project sharing