OpenArm is a human-scale 7-axis arm by Enactic aimed at physical AI research, usually built as a two-arm system with leader arms for teleoperation. It uses backdrivable Damiao brushless actuators over CAN for compliant, safer contact with people, with a nominal payload of 4.1 kg. Version 2.0 adds a camera gripper, a standardized evaluation cell and a planned motorless leader device.
At a glance
| Parts cost | $6,500 system · The project's price for a complete two-arm system. It gives no separate figure for self-sourced parts source ↗ |
|---|---|
| Difficulty | 5/5 Expert · Machined and sheet-metal parts, custom harnesses, CAN setup and motor firmware config, at research-lab cost. |
| Build time | Not stated |
| Tools needed | CNC-machined and sheet-metal parts ordered through MISUMI meviy, 3D printer for v1 printed parts, cable crimping and harness making, CAN-FD USB adapter |
| Motors | Damiao DM-J4310-2EC, DM4340 and DM-J8009P brushless actuators |
| Controller | PC over CAN-FD (USB CAN adapter), ROS 2 or Python |
| Sensors | Motor encoders; v2.0 gripper has a built-in camera |
| Published | ✓ Parts list✓ CAD/STL✓ Assembly guide✓ Wiring✓ Software✗ Video Docusaurus docs site (docs.openarm.dev), CAD and parts list on Google Drive, many GitHub repos, Discord |
| Activity | Last update 2026-09-29 · 3,556 GitHub stars · Discord, GitHub Discussions, 382 forks; hardware repo 522 stars |
| Kits | DIY kits and assembled units from listed manufacturers such as RT Corporation |
Licenses
| Design files | CERN-OHL-S-2.0 (strongly reciprocal) for CAD, STL and STEP source ↗ |
|---|---|
| Code | Apache-2.0 (openarm_can, openarm_ros2, teleop, simulation repos) source ↗ |
| Documentation | Apache-2.0 (docs website source lives in the openarm repo) source ↗ |
Builder notes
Practical points from the project's issue tracker, forum and docs, each linked to its source.
- The step-by-step assembly, wiring and parts list pages are in the 1.0 docs. The 2.0 docs mainly link to a Google Drive with STEP and parts list, so 2.0 builders work from CAD plus the 1.0 guides. source ↗
- Some MISUMI meviy part numbers for the v2 end effector were not publicly visible, so they could not be ordered from some regional MISUMI sites until the team fixes it. source ↗
- The straight connector on the J4 motor cable hits an aluminum spacer and can bend or break. Enactic makes L-shaped connectors in-house. source ↗
- Hardware files are CERN-OHL-S (strongly reciprocal) while software is Apache-2.0, which caused confusion about what 'fully open source' covers. source ↗
- Thread-locked screws in the Damiao 4340 motor caps tend to strip during disassembly, and the team tested several removal methods. source ↗
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