Open Duck Mini v2
A 42 cm take on Disney’s BDX droid that learns to walk with reinforcement learning in MuJoCo.
Project documentationBefore you build
Five answers, each linked to its source
What does it cost?
Under $400full BOM
The maker says the full BOM should come in under $400. README
Can I sell what I build?
Check firstCheck before commercial use
Hardware Apache-2.0 · Software Apache-2.0 main repo; runtime unlicensed. Licensing source
What’s open?
3 of 6CAD: AvailableBOM: AvailablePCB: Not documentedCode: PartialSim: AvailableGuide: Partial
Code, guide partial · PCB not documented. All six files
What does it run on?
Simulation: MuJoCo model; training has moved to MuJoCo Playground. Software
Is it maintained?
Active
Latest activity Sep 7, 2026 · main repo last commit Jan 31, 2026 · 6 commits in the last 52 weeks · 6 contributors Activity
01 / Under the shell
The specifications.
Hardware, build and software on one sheet. Every fact links to where we found it.
A miniature version of Disney’s BDX droid, about 42 cm tall with its legs extended. It walks with reinforcement-learning policies trained in MuJoCo and runs them on an onboard Raspberry Pi Zero 2W. Hugging Face and Pollen Robotics sponsor the project.
Hardware
- Actuators
- Not documented Documentation
- Build
- 3D-printed · print guide in repo Documentation
- Height
- About 42 cm with legs extended README
- Inspiration
- Disney’s BDX droid README
- Onboard computer
- Raspberry Pi Zero 2W README
- Walking
- Reinforcement-learning policies (ONNX) moved from sim to the real robot README
- Actuator model
- Identified with Rhoban’s BAM tool README
- Sponsors
- Hugging Face and Pollen Robotics README
Building it
Software & simulation
- Runs on
- MuJoCoRaspberry Pi
- MuJoCo Playground
- RL training environment in Open_Duck_Playground README
- Embedded runtime
- Open_Duck_Mini_Runtime runs policies on the Raspberry Pi; last commit 7 Sep 2026 GitHub
- Reference motions
- Generator for imitation-learning reference motions README
02 / The files behind the robot
What’s open.
Six parts of the build, each checked separately. Gaps stay visible.
| Part | Status | What’s there | License | Source |
|---|---|---|---|---|
| CAD | Available | Public Onshape document, plus STL and STEP files in the repo | Apache-2.0 | README |
| Bill of materials | Available | Google Sheet, plus a Chinese version | Not documented | BOM sheet |
| Electronics | Not documented | Not established from the sources we read | Not documented | No source found |
| Code | Partial | Runtime and training code live in companion repos that have no license file | None found | Runtime repo |
| Simulation model | Available | MuJoCo model; training has moved to MuJoCo Playground | Apache-2.0 | README |
| Assembly guide | Partial | Tnkr build guide; the repo’s own assembly guide is marked incomplete | Not documented | Tnkr |
03 / Know before you build
Can you sell it?
Check firstCheck before commercial use
The main repository, with the design files, is Apache-2.0, which allows commercial use. The runtime and training repos have no license file, so no reuse rights are granted for that code. Ask the maker before shipping a product on it.
- Hardware
- Apache-2.0
- Software
- Apache-2.0 main repo; runtime unlicensed
04 / The upstream project
Is it maintained?
ActiveLatest activity Sep 7, 2026, 44 days before the snapshot
The main repository’s last commit was Jan 31, 2026.
- Stars
- 4,338
- Forks
- 551
- Contributors
- 6
- Latest release
- None recorded
Work has moved to companion repos. The runtime’s last commit was 7 Sep 2026, so the project counts as active, not just this repo.
Companion repositories
Snapshot captured Oct 21, 2026. Recorded figures, not live metrics. Active: activity within 90 days of the snapshot. Quiet: within a year. Dormant: longer.
05 / Parts & kits
A head start.
Maker-listed sellers only. No affiliate links or paid placement.
Kit availability is not documented in our reviewed sources.
06 / Side by side
Compare with other bipeds.
Other bipeds in the directory, most recently active first. Same sources, same rules.
| Robot | Cost | Open files | Can I sell it? | Runs on | Maintained | Stars |
|---|---|---|---|---|---|---|
| Open Duck Mini v2This robotAntoine Pirrone and contributors | Under $400full BOM | 3 of 6 | Check firstHW Apache-2.0 · SW Apache-2.0 main repo; runtime unlicensed | MuJoCoRaspberry Pi | ActiveSep 7, 2026 | 4,338 |
| XGO-DuckLuwu Dynamics | Not documented | 4 of 6 | Check firstHW not documented · SW not documented | Arduino | ActiveOct 30, 2026 | 1,644 |
| LeRobot Humanoidhuggingface | Not documented | 4 of 6 | YesHW Apache-2.0 · SW Apache-2.0 | Raspberry PiPython | ActiveAug 27, 2026 | 40 |
| This robotOpen Duck Mini v2 | XGO-Duck | LeRobot Humanoid |
|---|---|---|
| Cost | ||
| Under $400 | Not documented | Not documented |
| Can I sell it? | ||
| Check first | Check first | Yes |
| Open files | ||
| 3 of 6 | 4 of 6 | 4 of 6 |
| Runs on | ||
| MuJoCo, Raspberry Pi | Arduino | Raspberry Pi, Python |
| Maintained | ||
| ActiveSep 7, 2026 | ActiveOct 30, 2026 | ActiveAug 27, 2026 |
Upkeep is measured against each robot’s own snapshot. Costs keep the maker’s scope, so check what each figure covers.
See them in the tableConnected projects and guides
Keep exploring.
07 / Follow the evidence
Open books.
Repository files are pinned to commit b23317a. Websites and papers are listed with their review dates.
- 01README at commit b23317aReviewed Oct 21, 2026
- 02LICENSE (Apache-2.0)Reviewed Oct 21, 2026
- 03Open_Duck_Mini_Runtime: no license file at the repo rootReviewed Oct 21, 2026
- 04Open_Duck_Playground: no license file at the repo rootReviewed Oct 21, 2026
- 05GitHub API: stars, contributors, commit activityReviewed Oct 21, 2026