compareeHub

YOU CAN BUILD A WALL OF 80 STEEL BALLS THAT FLOAT AND RIPPLE LIKE LIQUID METAL

80 polished steel balls hanging on independent cables, each driven by its own motor to draw waves and shapes in mid-air — museum-grade kinetic art you can actually build.

by Andrew Kotite and Ben Oztalay

FULL CAD BOM FIRMWARE DOCS

DisplaysRobotics

Built withRaspberry Pi

difficulty
●●●●●
time
several weekends
license
MIT
repo
repo FINISHED7 stars

WHAT YOU’LL NEED

Videos
1
Jump to section

COMPAREE VERDICT

This is one of the most visually striking kinetic sculptures documented online, but only the animation side is open: a Python simulator whose animations run directly on the real sculpture. Andrew Kotite and Ben Oztalay built an 8 by 10 grid of 30 mm solid steel balls on cables, each moving through about five feet of vertical travel with roughly 0.5 mm resolution, inspired by ART+COM Studio's The Shape of Things to Come. The Hackaday write-up explains the architecture well: 3D-printed modules of four geared motors with a custom board and two microcontrollers each, a Raspberry Pi coordinating the chain, a limit switch above every ball for homing, and 172 addressable RGB LEDs in the base. If you want to write animations, the simulator gets you going in minutes. The animation code is the easy part; the motor firmware, custom module PCBs and 3D-printed housings you would have to recreate yourself.

GOOD TO KNOW

  • —Only the Python animation simulator is public; the module firmware and the Raspberry Pi control software are not published.
  • —No CAD files for the frame, motor mounts, or cable routing
  • —No bill of materials — you are reverse-engineering the hardware from the write-up and photos
  • —The detailed write-up on Hackaday.io describes the motor modules, cable setup, homing, lighting and control architecture
  • —MIT license allows commercial use
  • —This is a finished installation — the repository is the choreography code and simulator, not a step-by-step build guide

Parts to buy

10 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • 80 geared DC motors with encoders and worm gearboxesFind
  • 80 drilled and tapped 30 mm steel ballsFind
  • CableFind
  • PulleysFind
  • Custom motor-driver PCBs (one per four motors)from the repo files
  • Homing boards with micro switchesFind
  • 172 addressable RGB LEDsFind
  • Raspberry PiFind
  • 6 V and 5 V power suppliesFind
  • Base plate and enclosure materialFind

BUILDS OF THE WEEK

Five open-source builds worth your weekend, every week.

Checked like this one: what’s really in the repo, what it costs, how hard it is. One email, unsubscribe anytime.

Can I build this?

PrintMotor module housings and ball guides (the originals were 3D printed, but the files are not published — you would design your own)
Buy80 geared DC motors with encoders and worm gearboxes, 80 drilled and tapped 30 mm steel balls, cable, pulleys, custom motor-driver PCBs (one per four motors), homing boards with micro switches, 172 addressable RGB LEDs, a Raspberry Pi, 6 V and 5 V power supplies, base plate and enclosure material
Toolsdrill, tap set, soldering iron, cable crimping tools, multimeter, patience for mechanical alignment
Skillsadvanced — requires experience with multi-motor coordination, encoder tuning, frame construction, and large-scale project planning; the code is intermediate Python, but the hardware is expert-level
Timeseveral weekends — mechanical build and calibration dominate
Cost$$$, driven by 80 motors, encoders, power supplies, and frame material
SafetyMains voltage for power supplies. Moving cables under tension — finger trap hazard during operation or testing. Otherwise no unusual risk.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

Andrew Kotite's own video shows the finished sculpture running; there is no build or setup walkthrough.

More builds like this

All projects
310 printed parts become a real WALL-E you drive from your phoneRoboticsYou can build a drawing robot out of two sticks and a pencil for about 14 eurosRoboticsThese 60 dollars 3D-printed gloves let you actually feel objects in VRDisplays

Gallery

cdn.hackaday.io
cdn.hackaday.io
cdn.hackaday.io

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read the Hackaday.io write-up to understand the motor modules, cable setup and control architecture (This is your primary reference — the write-up describes the motor modules, cable attachment, homing plates, lighting and control architecture.)
  2. 2.Clone the simulator and control code (Run the Python simulator to see how animations are defined and test patterns before building hardware.)
  3. 3.Source motors with encoders that match the travel range and precision requirements(The write-up describes about 1.5 m of travel and 0.5 mm resolution — you need geared motors with encoders; expect significant cost and lead time for 80 units.)
  4. 4.Design or adapt a frame to hold 80 motors in the arrangement you want(No CAD is provided — you are building this part yourself. Aluminium extrusion is a common choice for rigidity and modularity.)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • No CAD files or BOM — you are reverse-engineering the entire mechanical build from the write-up, photos and video, which is the single biggest time sink.
  • 80 motors with encoders is a large upfront cost and a long lead time if you are sourcing them yourself — budget for both.
  • Cable routing and friction tuning is where most of the build time goes — one sticky pulley or misaligned cable and that ball will not move smoothly.
  • Power distribution for 80 motors plus 172 LEDs is non-trivial — plan your supply topology before you start wiring.
  • The frame must be rigid enough to hold precision over 1.5m of cable travel while looking gallery-clean — a wobbly frame will show in every animation.
  • Skipping automatic homing — the original zeroes every ball against its own micro switch; without that, encoder drift across 80 motors will knock the balls out of sync.

Is there a bill of materials?

No. The Hackaday write-up describes the motor type and general setup, but you will be sourcing and speccing everything yourself.

Can I build a smaller version to test the concept?

Yes, and that is the recommended path — start with a 4×4 or 5×5 grid to prove the motor control, cable routing, and animation code before committing to 80 units.

What motors did they use?

The write-up describes geared DC motors with encoders and worm gearboxes, four per module, moving each ball through about five feet of vertical travel with an effective resolution of about 0.5 mm. No specific part number is given, so you will need to find equivalent motors yourself.

How loud is it?

80 motors running simultaneously will produce audible hum and whir — this is not silent kinetic art, though the write-up does not quantify noise level.

Can I run this outdoors?

The design assumes indoor installation — motors, electronics, and steel balls are not weatherproofed, and wind will interfere with cable tension and positioning.

Community builds

No community builds yet — be the first, we feature the best ones.

Discussion1

FROM THE COMPAREE TEAM

80 motors, 172 LEDs, and about 1.5 metres of travel per ball — with only the animation simulator published. Would you design the hardware from the write-up to build one, or start with a single four-motor module first?

CompareeTEAM2mo agoedited

Practical notes from our verification: the only public code is SculptureSimulator, a Python animation simulator — the motor control firmware, Raspberry Pi coordinator code, CAD and BOM are not published. The Hackaday page has no build logs, but its detailed write-up explains the architecture: 3D-printed modules of four DC motors with encoders and worm gearboxes, a custom PCB per module with two microcontrollers, a Raspberry Pi coordinating the chain, a limit switch above each ball for automatic homing, and 30 mm steel balls moving through about five feet of vertical travel. The creators also published a video of the finished sculpture. This is not a weekend build — it is a multi-month custom installation project, and without published files you would be designing the PCBs, housings and frame yourself. If you have done large-scale motorised art before, the write-up and simulator will get you started. If you have not, build a small test module first. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

Andrew Kotite and Ben Oztalay

Andrew Kotite and Ben Oztalay built this sculpture as their own take on ART+COM Studio's The Shape of Things to Come: an 8 by 10 grid of steel balls on cables, with custom motor modules, built-in lighting and a simulator for writing new animations.

Star the project on GitHub

DISCLAIMER

  • Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
  • Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
  • Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
GitHub repo