Bastl — electroacoustic instrument

Grain Kalimba

A kalimba made of solid oak, played like a game controller – joystick, buttons and a motion sensor break its sound into a thousand tiny grains.

FH Joanneum · 2023/24 Oak · CNC Granular synthesis

↑ Play me – tap the tines

What is the Grain Kalimba?

A thumb piano with a built-in sound cloud.

A pickup captures the metal tines, a small computer inside the body breaks the sound into tiny grains and puts it back together – into pads, loops and textures.

Everything is controlled right on the instrument, with a joystick, buttons and knobs. No laptop needed. Created as a project during my studies at FH Joanneum.

Listen

Soundcheck

At first it sounds like a kalimba. Then it doesn’t.

▶

Play video Playing the video loads it from YouTube.

2026

An electroacoustic instrument

Plucked notes, sent live through the granular synthesizer: frozen, stretched and layered into soundscapes.

From design to instrument

in six steps

Design

Sketches and 3D models in Fusion 360: how do you hold a kalimba that’s also supposed to be a joystick?

Interface

Control prototypes with TouchOSC on a tablet: how many buttons does it need – and where do they go?

Prototype

Schematic in Fritzing, then everything onto the breadboard: Teensy, buttons, LEDs and joystick in the first test.

Milling

Body of solid walnut, milled on my CNC. The first one couldn’t take the tension of the tines – the second one could.

Electronics

Controls on top, underneath a Raspberry Pi Zero 2 W, sound card and power supply. Lots of soldering in very little space.

Software

The code of Mutable Instruments Clouds, compiled for Linux and built into Pure Data – starts automatically on power-up.

User manual of the 2.0

The controls

everything in one hand

Joystick + 4 pads

The pads choose what the joystick shapes – pitch, size, feedback and density, several at once if you like.

Preset

Hold it and pick a playing mode with one of the pads: Granular, Looping, Stretch or Spectral.

Freeze

Freezes the sound while you keep playing.

Position

A slider chooses where in the sound buffer the grains start.

Dry / Wet

Blends the real kalimba with the sound cloud.

Rotary knobs

Encoders with LED rings for reverb and texture spread.

Volume

A knob on top of the body.

Motion mode

A built-in motion sensor turns the whole instrument into a joystick: X and Y come from the movement. To switch it on: hold Preset, briefly press Freeze.

Tech