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Intermediate build

How to build OpenArm

8-DoF desktop robot arm · Intermediate

Build OpenArm by Enactic: a human-scale 7-DoF arm with backdrivable QDD CAN motors, 4.1 kg nominal payload and force-feedback teleop, ≈$6,500 per bimanual set.

Start the buildProject files
Difficulty
Intermediate

Some soldering, calibration and Linux comfort needed.

Build time
2–4 weekends

Our estimate, part-time

Parts cost
$6,500

≈$6,500 per bimanual system (Enactic)

Degrees of freedom
8

CERN-OHL-S-2.0

What is OpenArm?

OpenArm is Enactic's human-scale, seven-degree-of-freedom arm for physical-AI research in contact-rich settings. It's proportioned for a person about 160–165 cm tall, and its quasi-direct-drive motors are highly backdrivable, which makes it safer to work beside than a heavily geared arm.

The whole project is open. The CAD, BOM and fabrication data are released under CERN-OHL-S-2.0, and the CAN library, ROS 2, MuJoCo and Isaac Lab packages under Apache-2.0. Enactic quotes about $6,500 for a complete bimanual system and lists verified vendors for kits.

Version 2.0 adds a gripper with a built-in camera, an aluminium-frame base, the OpenArm Cell evaluation booth, and KER, a motorless leader arm with matching kinematics for teleoperation.

Versions and forks

  • OpenArm 1.0
  • OpenArm 2.0
  • KER leader
  • OpenArm Cell

OpenArm specifications

DoF
7 per arm + gripper
Payload
4.1 kg nominal, 6.0 kg peak
Actuators
Damiao QDD motors on CAN
Teleop
Bilateral force feedback
Software
openarm_can, ROS 2, MuJoCo, Isaac Lab
License
CERN-OHL-S-2.0 hardware / Apache-2.0 software

Figures as published by the project. See Sources below.

Bill of materials

PartQtyNotes
Damiao QDD motors—Sized per joint
Machined metal parts—
3D-printed covers—
USB-CAN interface—
Frame base (v2.0)—
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 $6,500 as a ballpark from the project. Start at the project repository.

Tools you'll need

  • Metric hex keys and torque driver
  • Crimp tools
  • Linux PC with SocketCAN
  • Bench supply

Step-by-step build overview

Electronics & wiring overview

Every joint motor has its driver built in and sits on one shared CAN bus, so only power and CAN run through the arm. Mechanical stops limit joint travel for safety.

DC power supplypower sourceLaptop / PChigh-level controlEncoderssensingMicrocontrollerreal-time controllerMotor driverdrivers / busMotors8 joints / motors
PowerData / commandsSensor feedbackOverview only. Follow the project's own schematic for pinouts and voltages.

Software

LeRobotURDF model

Separate repos cover the CAN library, URDF, ROS 2 control and MoveIt, MuJoCo, Isaac Lab, teleop and datasets.

Tips from the bench

  • ☕ Read the safety guide first.
  • ☕ Check whether each repo supports v1.0 or v2.0.
  • ☕ Join the community Discord.

OpenArm FAQ

How much does OpenArm cost?

About $6,500 for a bimanual system, according to Enactic.

What's the payload?

4.1 kg nominal and 6.0 kg peak per arm.

What license does it use?

CERN-OHL-S-2.0 for the hardware and Apache-2.0 for the software.

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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