Open source Mini humanoids & bipeds
Open Duck Mini v2
An open-source mini biped inspired by Disney’s BDX droid: about 42 cm, 16 joints, 14 Feetech bus servos and RL walking that works sim-to-real — around €400 in parts.
- Type
- Mini biped
- Joints
- 16
- Height
- ≈ 42 cm
- Servos
- Feetech STS3215 × 14
- BOM cost
- ≈ €398.10
- Structure
- PLA + TPU prints
- Open hardware and open code
- Full bill of materials with supplier links
- Direct links to the original CAD, code and papers
01 — Project details
Overview, BOM and resources
Overview
Open Duck Mini is built by Antoine Pirrone and the community, sponsored by Hugging Face and Pollen Robotics. Walking policies are trained in MuJoCo Playground and run on a Raspberry Pi Zero 2W.
Five joints per leg, four in the neck and head, and two antennas. The community has added shell, e-stop panel and head mods, and there is a Chinese build guide.
Key specifications
| Servos | 14 × Feetech STS3215 7.4 V bus servos + 9 g servos (antennas) |
|---|---|
| Controller | Raspberry Pi Zero 2W + Waveshare bus-servo driver |
| Sensors | BNO055 IMU, foot contact switches; optional camera and mic |
| Power | 2 × 18650 (2S) + BMS + 5 V UBEC |
Bill of materials
Total €398.10 (estimated minimum €331.10); with the optional expression package (eye LEDs, projector, speaker, mic, camera) €432.34.
Download the BOM (.xlsx) · Official BOM ↗
| Part | Model / spec | Qty | Unit | Subtotal | Supplier |
|---|---|---|---|---|---|
| Power | |||||
| 18650 cell | 2 | €5.00 | €10.00 | nkon.nl ↗ | |
| 18650 cell holder | 1 | €4.99 | €4.99 | amazon.fr ↗ | |
| 2S BMS | 1 | €8.40 | €8.40 | shorturl.at ↗ | |
| 5V regulator | 1 | €4.00 | €4.00 | shorturl.at ↗ | |
| Small power switch | 1 | €4.49 | €4.49 | amazon.fr ↗ | |
| usb-c charger | 1 | €9.99 | €9.99 | amazon.fr ↗ | |
| 2.1mm barrel jack | 2 | €1.00 | €2.00 | amazon.fr ↗ | |
| XT15? XT30 ? | 1 | €8.00 | €8.00 | amazon.fr ↗ | |
| Servos, control and sensors | |||||
| IMU (BNO055) | 1 | €40.00 | €40.00 | amazon.fr ↗ | |
| Raspberry pi zero 2w | 1 | €26.08 | €26.08 | t.ly ↗ | |
| SD card | 1 | €10.00 | €10.00 | amazon.fr ↗ | |
| Servo control board | 1 | €5.00 | €5.00 | waveshare.com ↗ | |
| Feetech 7.4v STS 3215 | 14 | €14.00 | €196.00 | alibaba.com ↗ | |
| Feet contact switches (SS-10) | 4 | €1.00 | €4.00 | fr.aliexpress.com ↗ | |
| 9g servos | 2 | €3.33 | €6.66 | amazon.fr ↗ | |
| MISC | |||||
| 3D printing M3 inserts | 1 | €5.99 | €5.99 | amazon.fr ↗ | |
| Standard PLA | 1 | €20.00 | €20.00 | ||
| TPU | 1 | €0.00 | €0.00 | ||
| Cable sheath | 1 | €9.00 | €9.00 | amazon.fr ↗ | |
| 15cm micro usb to usb-c cable | 1 | €7.00 | €7.00 | amazon.fr ↗ | |
| 50cm micro usb to usb c cable | 1 | €6.00 | €6.00 | amazon.fr ↗ | |
| Bearing | 3 | €3.50 | €10.50 | amazon.fr ↗ | |
| Total | €398.10 | ||||
Optional items, tools and reference items (not counted)
| Part | Model / spec | Qty | Unit | Subtotal | Supplier |
|---|---|---|---|---|---|
| Expression package | |||||
| Projector reflector | 1 | €2.00 | €2.00 | fr.aliexpress.com ↗ | |
| Speaker | 1 | €6.00 | €6.00 | amazon.fr ↗ | |
| Leds (for eyes and projector) | 3 | €0.20 | €0.60 | amazon.fr ↗ | |
| Microphone | 1 | €15.00 | €15.00 | amazon.fr ↗ | |
| Eye diffusers | 4 | €0.16 | €0.64 | amazon.fr ↗ | |
| Amplifier | 1 | €5.00 | €5.00 | amazon.fr ↗ | |
| Raspberry pi camera | 1 | €5.00 | €5.00 | fr.aliexpress.com ↗ | |
| Total | €398.10 | ||||
3D printing & fabrication
- All parts in standard PLA at 15% infill; foot_bottom_tpu in TPU at 40%.
- About 500 g of PLA; M3 heat-set inserts required.
- The 36 official STLs are in the repository’s print folder; community mods (shell, head) are alongside.
CAD, code & papers
Get the large files — CAD, STL, STEP and code — straight from the original project:
- GitHub (main) ↗github.com
- CAD (Onshape) ↗cad.onshape.com
- Official BOM (Google Sheets) ↗docs.google.com
- Runtime (Pi Zero 2W) ↗github.com
- RL training (Playground) ↗github.com
- Reference motion generator ↗github.com
- Build guide on Tnkr ↗tnkr.ai
- Chinese build guide (Feishu) ↗zihao-ai.feishu.cn
License
The main Open_Duck_Mini repository is Apache-2.0. Open_Duck_Mini_Runtime, Open_Duck_Playground and Open_Duck_reference_motion_generator have no LICENSE file (checked 2026-10-21), so all rights are reserved by default — reference only.
Image credits
- Image 1: Antoine Pirrone (apirrone) and community contributors · repo Apache-2.0, image not separately licensed — source ↗
- Image 2: Antoine Pirrone (apirrone) and community contributors · repo Apache-2.0, image not separately licensed — source ↗
- Image 3: Antoine Pirrone (apirrone) and community contributors · repo Apache-2.0, image not separately licensed — source ↗
- Image 4: Antoine Pirrone (apirrone) and community contributors · repo Apache-2.0, image not separately licensed — source ↗
- Image 5: Antoine Pirrone (apirrone) and community contributors · repo Apache-2.0, image not separately licensed — source ↗
Source: Images and data: Open Duck Mini project (Antoine Pirrone and community, GitHub apirrone/Open_Duck_Mini). Main repository Apache-2.0. Design inspired by Disney’s BDX; this site is not affiliated with Disney or the original project.
Get the parts
Where to get the parts
Every line in the BOM links to the supplier the original team used. Need help sourcing parts or 3D-printing the structure? Tell us which robot you are building.
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