Open source Quadrupeds
ODRI Solo-12
A torque-controlled open-source quadruped from the Open Dynamic Robot Initiative (MPI, NYU and partners): 12 DoF, 2.5 kg and foldable, with actuators, electronics and control software all open.
- Type
- Quadruped
- DoF
- 12
- Weight
- 2.5 kg
- Folded
- 45 × 30 × 6 cm
- Actuators
- custom 9:1 belt-drive modules
- Cost
- not published (Solo-8 materials ≈ €4,000)
- 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
Each Solo-12 leg has hip abduction, hip flexion and knee joints, enough for jumps and flips. At its core is an open actuator module — 3D-printed housing, two-stage 3:1 belt reduction and a drone brushless motor, at just 150 g.
The same actuator builds Solo-8, a 6-DoF biped and robotic fingers. The electronics (Master Board + Micro Driver) and control interface are open too.
Key specifications
| Actuator | T-Motor Antigravity 4004 300KV + 9:1 belt drive + Broadcom AEDT-9810 encoder; 2.5 N·m at 12 A |
|---|---|
| Drivers | 6 × Micro Driver Board v2 + Master Board v2 (ESP32, Ethernet / WiFi) |
| IMU | Lord Microstrain 3DM-CX5-25 |
| Structure | FDM PC-ABS or SLS shells; Multijet / SLA precision pulleys |
Bill of materials
The official BOM lists parts, quantities and suppliers without prices (mostly European suppliers; quote on request).
| Part | Model / spec | Qty | Link |
|---|---|---|---|
| Solo-12 v1 robot (×1) | |||
| 3DOF Leg | 3DOF Leg Documentation | 4 | |
| Master Board v2 | 1 | github.com ↗ | |
| Micro Driver Board v2 | Micro Driver Documentation | 6 | |
| Inertia Measurement Unit | 1 | microstrain.com ↗ | |
| Body Structure Back | 1 | ||
| Body Structure Bottom | 2 | ||
| Body Structure Center | 1 | ||
| Body Structure Center Handle | 1 | ||
| Body Structure Center Vicon | 1 | ||
| Body Structure Front | 1 | ||
| Body Structure Hip AA Support | 4 | ||
| Body Structure Side | 4 | ||
| Body Structure Top IMU | 1 | ||
| Body Structure Top Master Board | 1 | ||
| Led Cover | 1 | ||
| Hip Adapter | 2 | ||
| Spacer Micro Driver Stack | 16 | ||
| Hip AA Bearing | 25mm x 20mm x 4mm ; ET2520 2Z VA | 4 | sbn.de ↗ |
| Fasteners Body Structure Side | M3x12 Socket Head Cap Screw | 16 | online-schrauben.de ↗ |
| Fasteners Body Structure Center | M3x8 Socket Head Cap Screw | 8 | online-schrauben.de ↗ |
| Fasteners Hip AA Actuator Modules | M2,5x10 Socket Head Cap Screw | 16 | online-schrauben.de ↗ |
| Fasteners Hip AA Support | M3x14 Socket Head Cap Screw | 8 | online-schrauben.de ↗ |
| Fasteners Micro Driver Stack | M2,5x25 Socket Head Cap Screw | 8 | online-schrauben.de ↗ |
| Fasteners IMU | M2,5x16 Slotted Screw ; Conrad 839940-62 | 3 | |
| Helicoil M3 x 4,5mm | 32 | hoffmann-group.com ↗ | |
| Vicon Markers Ø 9,5mm | 13 | vicon.com ↗ | |
| Fasteners Vicon Markers | M4x10 Set Screw | 13 | online-schrauben.de ↗ |
| Solo-12 v1 — robot stand | |||
| Stand Fork | 2 | ||
| Stand Foot | 4 | ||
| Slotted Profile Vertical | 2 | us-product.item24.com ↗ | |
| Slotted Profile Horizontal | 1 | us-product.item24.com ↗ | |
| Angle Bracket | 4 | product.item24.de ↗ | |
| Fastener Stand Fork | M8x25 Flat Head Screw | 2 | online-schrauben.de ↗ |
| Fastener Stand Foot | M5x20 Socket Head Cap Screw | 8 | online-schrauben.de ↗ |
| Rubber Feet | 4 | export.rsdelivers.com ↗ | |
| Leg 3-DoF v1 (×4 per robot) | |||
| Core Components | Actuator Module Core v1 ; Actuator Module Core v1.1 | 3 | |
| Hip AA Module Shell Base | 1 | ||
| Hip AA Module Shell Cover | 1 | ||
| Hip FE Module Shell Base | 1 | ||
| Hip FE Module Shell Cover | 1 | ||
| Upper Leg Module Shell Base | 1 | ||
| Upper Leg Module Shell Cover | 1 | ||
| Lower Leg v2 | 1 | ||
| Lower Leg v3 | 1 | ||
| Rubber Foot | Bicycle tire - for example: Schwalbe Lugano 28" 23-622 | ||
| Fasteners M3x35 | M3x35 Socket Head Cap Screw | 2 | |
| Fasteners M3x22 | M3x22 Socket Head Cap Screw | 2 | |
| Fasteners M3x16 | M3x16 Socket Head Cap Screw | 2 | |
| Fasteners M3x12 | M3x12 Socket Head Cap Screw | 2 | |
| Washer M3 | 2 | ||
| Fasteners M2,5x6 | M2,5x6 Socket Head Cap Screw | 12 | |
| Fasteners M2,5x10 | M2,5x10 Socket Head Cap Screw | 15 | |
| Helical Inserts M2,5x3,75 | Hoffmann 082814 M2,5 ; McMaster 91732A767 | 27 | |
| Actuator Module Core v1 (×3 per leg, ×12 per robot) | |||
| T-Motor Antigravity 4004 300kV | 1 | ||
| Encoder Broadcom AEDT-9810-Z00 | 1 | digikey.com ↗ | |
| Codewheel for Encoder AEDT-9810-Z00 | 1 | ||
| Timing Belt Conti Synchroflex AT3 GEN III | width: 4mm / length: 150mm / 50 teeth ; Timing belt first stage | 1 | |
| Timing Belt Conti Synchroflex AT3 GEN III | width: 6mm / length: 201mm / 67 teeth ; Timing belt second stage | 1 | |
| Bearing Output Shaft | 32mm x 25mm x 4mm ; EZO bearing 61705 2RS VA | 2 | |
| Bearing Motor Shaft and Center Shaft | 8mm x 4mm x 2mm ; EZO bearing MR84 VA | 3 | |
| Bearing Timing Belt Tensioner | 7mm x 3mm x 3mm ; EZO bearing 683 2Z VA | 2 | |
| Encoder Codewheel PWB Mount | 1 | ||
| Transmission Pulley AT3 T30 Center | 1 | ||
| Transmission Pulley AT3 T30 Output | 1 | ||
| Timing Belt Tensioner Roller 10mm | 2 | ||
| Motor Shaft | PDF drawing | 1 | |
| Motor Pulley | PDF drawing | 1 | |
| Center Pulley | PDF drawing | 1 | |
| Fasteners Encoder | M3 x 16 Philipps Flat Head Screw | 2 | conrad.com ↗ |
| Fasteners Motor | M3 x 5 Flat Head Screw | 4 | online-schrauben.de ↗ |
| Fasteners Timing Belt Tensioner | M3 x 10 Flat Head Screw | 2 | online-schrauben.de ↗ |
| Washers Timing Belt Tensioner | M2,5 Washer | 2 | online-schrauben.de ↗ |
| Helical Insert Output Shaft | Helicoil M3 x 6 | 2 | mcmaster.com ↗ |
| Broadcom Encoder Kit AEDM-5810-Z12 | 1 | digikey.com ↗ | |
| Codewheel Mount Encoder Kit | 1 | ||
| Bearing Timing Belt Tensioner | SKF # 623-2Z ; 10mm x 3mm x 4mm | 2 | qualitybearingsonline.com ↗ |
| Fasteners Timing Belt Tensioner | M3 x 10 Flat Head Screw | 2 | online-schrauben.de ↗ |
| Washers Timing Belt Tensioner | M3 Washer | 2 | mcmaster.com ↗ |
| v1.1 autonomy upgrade (battery / wireless, optional) | |||
| Power Management Board | 1 | github.com ↗ | |
| LiPo Battery SLS X-Cube 850mAh | 2 | ||
| E-Stop Switch | RS 820-7587 | 1 | |
| On-Off Switch | RS 820-7593 | 1 | |
| Status Led Ring | Adafruit 1643 ; Mouser 485-1643 ; Conrad 1516560 | 1 | |
| Body Structure Center Payload | 2 | ||
| Body Structure Front Batterie Lid | 2 | ||
| Body Structure Front Batterie | 2 | ||
| Body Structure Top IMU Leds | 1 | ||
| Body Structure Top Master Power Board | 1 | ||
| Mount Switches | 1 | ||
| Neo Pixel Cover | 1 | ||
| Fastener M2 x 6 SHCS | 8 | ||
| Fastener M2,5 x 6 SHCS | 1 | ||
| Fastener M2,5 x 8 SHCS | 1 | ||
| Fastener M3 x 6 SHCS | 4 | ||
| Helicoil M2,5 x 3,75mm | 10 | ||
| Helicoil M3 x 4,5mm | 20 | ||
3D printing & fabrication
- Large parts (shells, body) in FDM or SLS — MPI prints PC-ABS on a Stratasys Fortus at 0.178 mm layers.
- Small precision parts such as pulleys need Multijet or SLA; the LED cover needs clear material.
- Print along the STL’s +Z axis and watch the bearing-seat tolerances.
CAD, code & papers
Get the large files — CAD, STL, STEP and code — straight from the original project:
- Project page ↗open-dynamic-robot-initiative.github.io
- Hardware repository ↗github.com
- Solo-12 build docs ↗github.com
- Master board firmware ↗github.com
- Control interface ↗github.com
- Paper arXiv:1910.00093 ↗arxiv.org
License
Hardware and control interface BSD-3-Clause; master-board BSD-2-Clause.
Image credits
- Image 1: Open Dynamic Robot Initiative (NYU & MPG) · BSD 3-Clause — source ↗
- Image 2: Open Dynamic Robot Initiative (NYU & MPG) · BSD 3-Clause — source ↗
- Image 3: Open Dynamic Robot Initiative (NYU & MPG) · BSD 3-Clause — source ↗
- Image 4: Open Dynamic Robot Initiative (NYU & MPG) · BSD 3-Clause — source ↗
- Image 5: Open Dynamic Robot Initiative (NYU & MPG) · BSD 3-Clause — source ↗
- Image 6: Open Dynamic Robot Initiative (NYU & MPG) · BSD 3-Clause — source ↗
Source: Images and data: Open Dynamic Robot Initiative (GitHub open-dynamic-robot-initiative and arXiv:1910.00093). Hardware BSD-3-Clause, master-board BSD-2-Clause. This site is not affiliated with 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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