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Cubli Armonia Reaction-Wheel Cube

A 156 mm reaction-wheel cube that balances on an edge and on a corner, using three reaction wheels, a Teensy 4.1 control loop and a Wi-Fi telemetry bridge.

  • Other
  • Open source
  • arduino

Suggested by Robotheca, created by @NiccoloTonetto (opens in a new tab), from github.com/NiccoloTonetto/Cubli-Space-challenge-2026 (opens in a new tab). Pinned to commit 1b6e3d0 (opens in a new tab).

Fork on GitHub (opens in a new tab)Download the files at this commit (.zip)
Hardware license
MIT (opens in a new tab)
Software license
MIT (opens in a new tab)
Commercial use
Allowed

Photo and 3D model

Cubli Armonia Reaction-Wheel Cube, photo from its repository
Photo:@NiccoloTonetto (opens in a new tab)MITsource file (opens in a new tab)

3D preview converted from github.com/NiccoloTonetto/Cubli-Space-challenge-2026 at 1b6e3d0, under MIT. View the original files from GitHub (13.5 MB) (opens in a new tab)

Weight
1.615 kg

What it can do

Written by Robotheca from the project's documents.

  • Balances a 156 mm reaction-wheel cube on an edge and on a corner, per the README.
  • Corner balance reported at 373.5 s continuous with tilt RMS 0.40 degrees.
  • Edge balance reported at 197 s continuous with tilt RMS 0.58 degrees.
  • Recovers from disturbances of about 3 degrees in 0.08 to 0.20 s, per the README.
  • Only corner [-1,-1,-1] has been flown; gains for other corners are not yet in firmware.
  • Balance only; no jump-up is implemented.

Bill of materials

This repository has no parts list Robotheca can read yet.

Build guide

The creator's steps, each with its instructions.

  1. 1Print the 156 mm PETG-CF frame
  2. 2Assemble the three reaction wheels with T-Motor Antigravity 4006 motors
  3. 3Mount the mjbots moteus-n1 FOC drivers on the CAN-FD bus
  4. 4Fit the Bosch BMI270 IMU at the cube's geometric centre
  5. 5Wire the Teensy 4.1 controller and XIAO ESP32-C6 Wi-Fi bridge
  6. 6Flash the staged bring-up firmware and calibrate the IMU
  7. 7Tune the per-corner LQR gains and balance on a corner

The guide appears here as you scroll.

Guide by @NiccoloTonetto (README.md), under MIT.

More guides

Wiring and electronics

Notes written by Robotheca from the project's documents.

Main parts

  • Teensy 4.1 running the 2 ms control loop.
  • XIAO ESP32-C6 acting as a Wi-Fi telemetry bridge.
  • Three T-Motor Antigravity 4006 motors.
  • Three mjbots moteus-n1 FOC motor drivers.
  • Bosch BMI270 IMU at the cube's geometric centre.
  • KiCad schematic and PCB files for the electronics are in the repository.

Connections

  • The three moteus-n1 drivers are connected on a CAN-FD bus, run at 1 Mbps.
  • The IMU sits at the cube's geometric centre, 130 mm from every corner.
  • The XIAO ESP32-C6 bridges telemetry over Wi-Fi.
  • Wiring details beyond these bus and placement facts are in the KiCad schematics, which the documents provided do not describe in text.

Schematics, boards and diagrams