New 5-Row MIDI Button Keyboard

This is a new revision of my compact MIDI button keyboard, designed for musicians who are familiar with button accordion layouts and want a portable expressive controller for modern MIDI workflows.

Unlike piano-style MIDI controllers, this instrument is built around the ergonomics of chromatic button accordion, bayan, and related free-reed instruments. It can be used for DAW work, note entry, live MIDI control, portable practice, and casual music-making while traveling.

The goal is simple: a small instrument that feels natural to button accordion players, but works with modern MIDI equipment and software.

What is new in this revision

This revision is much more than a simple MIDI controller. It adds a more complete standalone playing experience:

• built-in General MIDI sound engine
• built-in speaker
• headphone output
• built-in rechargeable battery
• velocity-sensitive buttons
• external breath controller support
• pitch bend control
• graphical menu interface
• USB-C MIDI and TRS MIDI output

It can work as a compact MIDI controller, but it can also be used as a small self-contained musical instrument.

Designed for button players

The keyboard is designed for musicians who are used to button-based layouts, including:

• chromatic button accordion players
• bayan players
• diatonic accordion / khromka players
• musicians who prefer compact button layouts over piano keys
• DAW users who want a portable non-piano MIDI input device

It is especially useful when a full accordion is too large, too loud, or simply inconvenient to carry.

Layouts

The keyboard supports multiple layouts:

• B-system
• C-system
• Stradella
• Converter B
• Converter C
• Khromka diatonic layout

Converter layouts are available in both one-hand and two-hand variants.

The layout can also be flipped by 180°, which makes it easier to adapt the instrument to different playing positions, mounting options, or personal preferences.

Expressive velocity response

This revision uses a velocity-sensitive key system designed for expressive playing.

The main key motion is detected with Hall-effect sensors, while an additional shock sensor can help improve response on very fast attacks. The firmware allows the velocity response to be adjusted, so the instrument can be tuned for different playing styles.

This is important because accordion players, pianists, and electronic musicians often expect different touch behavior from the same controller.

Built-in sound

The keyboard includes a built-in General MIDI sound engine, so it can be played without a computer or external synthesizer.

It has:

• built-in speaker
• headphone output
• General MIDI program selection
• reverb and chorus settings
• volume and output gain controls

The built-in sound is useful for quick practice, travel, testing layouts, or playing without a full studio setup.

Connectivity

The instrument supports both modern and classic MIDI workflows:

• USB-C MIDI
• TRS MIDI Type A
• USB-C and TRS MIDI can work at the same time
• compatible with Windows, Linux, macOS, and iOS

This allows the keyboard to connect to DAWs, software instruments, hardware synthesizers, MIDI modules, and experimental setups.

Breath controller

The keyboard supports an external breath controller for expressive MIDI control.

This can be useful for:

• wind-style expression
• soft synths
• hardware synthesizers
• expressive pads, leads, and orchestral sounds

The breath response can be adjusted in the menu.

Portable standalone instrument

The new revision is designed to be lightweight and easy to carry.

Approximate weight:

• keyboard: 420 g
• breath controller accessory: 50 g

Battery life:

• up to 8 hours with headphones
• up to 5 hours with the built-in speaker

The keyboard can also be worn with a neck strap, making it possible to use it as a very compact portable performance instrument.

Features

• 5-row button keyboard
• compact chromatic button accordion-style layout
• multiple layouts: B-system, C-system, Stradella, Converter B/C, Khromka
• velocity-sensitive buttons
• adjustable velocity response
• Hall-effect sensing with additional fast-attack sensing
• pitch bend control
• external breath controller support
• built-in General MIDI sound engine
• built-in speaker
• headphone output
• USB-C MIDI
• TRS MIDI Type A output
• USB-C and TRS MIDI can work simultaneously
• graphical menu interface
• transpose function
• layout flip by 180°
• rechargeable Li-ion battery
• lightweight and travel-friendly

Use cases

This keyboard can be used as:

• a portable MIDI controller for DAW work
• a compact practice instrument
• a button accordion-style input device for notation software
• a controller for external synths and sound modules
• a travel instrument for casual playing
• an experimental platform for alternative button layouts

It is designed for situations where a full accordion or large MIDI controller is too big, but a small expressive button instrument is still needed.

Development status

This project is under active development. I am currently collecting feedback from musicians to improve the firmware, playing response, and workflow.