Proprioception & Drum Machines

June 2, 2026

Try this exercise: close your eyes and reach an arm out to the side, then swing your arm to touch your fingertip to your nose. Next, explain how you were able to calculate the angles and trajectories of your shoulder, elbow, wrist, finger, and neck. If you can, you are ready for a job at the cutting edge of robotics. If you are like most people, touching your nose is trivial to do and impossible to explain.

Proprioception is the sense of force, movement, and positions of the parts of the body, which are delivered by specialized neurons embedded in joints and muscles. These nerves keep track of where your body is at all times, even if you are not aware of it.

This drum machine prototype is the end project of the proprioception chapter. It demonstrates a number of common senses in a (hopefully) fun project of a physical controller for a browser-based drum machine, inspired by classic machines like the Roland 808.

Drum machines are the foundation of modern music — from disco to techno. They play short audio samples in repeating loops, letting musicians program rhythms by placing hits at specific moments on a timeline. The iconic “four on the floor” rock beat, for example, is simply a bass drum on every fourth step.

Musicians used these tools to create complex compositions starting in the late 1970s. While synthesizers use a piano keyboard, drum machines have always had a more grid-like interface — and today that grid is usually on a screen. This project brings it back to physical controls.

The Roland 808 drum machine spawned thousands of bands in dozens of genres from Disco to Techno. Photo courtesy Bryan Pocius from New York, USA, via Wikimedia Commons

How It Works

The project has two parts: a microbit microcontroller and a web page.

The physical controls — sliders, knobs, and a button — connect to the microbit. The microbit reads the control inputs and sends them over a USB serial connection to the web page. The web page displays the drum grid, plays the audio samples, and updates in real time as you turn knobs and move sliders.

Drum Machine Web App

The web app works with the microbit (or you can click around on a desktop browser).

turbek.com/tangible-interfaces-drum-machine/drum_machine.html

The web page shows a 16-step by 8-track grid. Each row is one instrument track, and each column is one step in the rhythmic loop. Clicking a cell toggles whether that instrument plays on that step.

The tracks are split into two groups of four, with a horizontal divider between them. Each track label on the left shows the name of its current sample. A default loop is loaded when the page opens, with at least four active tracks.

Audio samples come from the 1LOVE Vintage Drum Kit on Freesound.org, which is released under a public domain license.

The drum machine web app is a toy program that can make surprisingly good beats.

Microbit Program

The microbit program reads the sliders, knobs, and button, then sends the values as structured messages to the web page over USB serial.

View the microbit program source

Open in MakeCode editor

Hardware

The hardware uses the microbit and several sensors to make the drum machine controller, but no complex engineering.

Microbit v2
Microbit breakout board (speeds up prototyping by making pins easy to wire)
Sliding potentiometer — step: selects the current step on the timeline
Sliding potentiometer — track: selects the current track
Rotary potentiometer — tempo: sets the playback speed in beats per minute, covering a slow-to-fast disco range
Rotary encoder — sample: selects the audio sample for the current track
Rotary encoder — jog: shifts the entire track forward or backward to create rhythmic “swing,” or nudges a single selected hit
Button: play / pause
Jumper wires with socket ends
USB cable

This wiring diagram shows how the components are wired. Note that power and ground wires are omitted for readability.

Prototype 1: Loose wires

The first prototype is just the components wired together on a desk. Quick to build and easy to change, but fragile.

Drum machine prototype — loose wires

Prototype 2: Taped to cardboard

Taping everything to a piece of cardboard gives the controls a fixed position, making it easier to use while testing.

Drum machine prototype on cardboard

Prototype 3: In a box

Mounting the controls in a small box creates something that feels like a finished instrument.

Drum machine controller in a box

Design

What should it look like? I will not steal the fun from you, but here are some wacky AI device inspiration.

Wacky AI product image 1

Wacky AI product image 2

Open sourced at github.com/steveturbek/tangible-interfaces-drum-machine