How to build Open Duck Mini
16-DoF expressive biped · Advanced
Build Open Duck Mini v2: a 42 cm Disney BDX-style walking droid with 16 servos, Raspberry Pi Zero 2W and RL policies, about €398 in parts.
Many actuators, custom wiring and real tuning work.
Our estimate, part-time
€398.10 for the base robot per the project BOM sheet
Apache-2.0
What is Open Duck Mini?
Open Duck Mini is Antoine Pirrone's small take on Disney's BDX droids, the expressive bipeds from the Star Wars parks. Version 2 stands about 42 cm and walks using reinforcement-learning policies trained in simulation.
It has 16 servos: ten in the legs, four in the head and neck, and two antennas. Power comes from two 18650 cells through a 2S BMS, so it runs untethered.
Everything is in the repo: a BOM sheet with vendor links, print and assembly guides, wiring notes, URDF and MuJoCo descriptions and the runtime code. A busy Discord community supports builders.
Open Duck Mini specifications
- Height
- ≈42 cm
- DoF
- 16 (10 legs, 4 head/neck, 2 antennas)
- Power
- 2× 18650, 2S BMS
- Control
- RL policies from MuJoCo
- License
- Apache-2.0
Figures as published by the project. See Sources below.
Bill of materials
| Part | Qty | Notes |
|---|---|---|
| Serial bus servos | 16 | Per the BOM sheet |
| Raspberry Pi and IMU | — | |
| 18650 cells, holder, 2S BMS, 5 V regulator, switch | — | |
| USB-C charger and barrel jacks | — | |
| Printed body and legs | — |
Where's the full bill of materials?
The full BOM, with exact quantities and vendors, lives in the project's own files. Prices change often, so treat €398 as a ballpark from the project. Start at the project repository.
Tools you'll need
- FDM printer
- Soldering iron
- Small hex drivers
Step-by-step build overview
Electronics & wiring overview
Two 18650s feed a 2S BMS; a 5 V regulator powers the Pi while the servos run from the pack. One small switch turns it all on.
Software
MuJoCo and URDF models for training, plus the on-robot runtime. Training code lives in companion repos linked from the README.
Tips from the bench
- ☕ Buy the best 18650s you can; the README is blunt about that.
- ☕ Ask on the Discord before changing servo models.
Open Duck Mini FAQ
How much does Open Duck Mini cost?
About €398 for the base robot per the BOM sheet.
Is it a real BDX droid?
No. It's a fan-made open design inspired by Disney's BDX.
Sources
Written by Bots n' Beans from the project's own documentation. Check the sources for the latest revision before you buy parts.
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