dora-openarm-keyboard

A dora-rs node that teleoperates OpenArm from the keyboard in a Web browser.

The node serves a web page (default http://127.0.0.1:8080/) that does both halves of teleoperation in one browser tab:

• Keys in: the page captures the key bindings below and sends them over a WebRTC data channel. They only work while the tab has focus, and losing focus (or closing the tab, or losing the network) releases every held key — an unwatched browser can never keep the robot moving.
• Video out: JPEG frames arriving on the node's optional image input are streamed to the page as WebRTC video. Wire it to a camera_* output of dora-openarm-mujoco --render to watch the simulation from the browser.

It publishes end-effector pose targets with the same output contract as dora-openarm-webxr, so it can be dropped into a dataflow wherever the WebXR node would normally sit and feed dora-openarm-ik unchanged.

Key bindings

Each arm has its own keys, so both can be driven at the same time with no arm to select first. Holding Shift turns the same keys into rotation.

Motion keys are hold to move: the target advances while the key is down and stops the moment it is released. Shift is momentary in the same way — the keys rotate only while it is down, and releasing it always returns to translation. Rotation is integrated in the tool frame, so roll, pitch and yaw stay relative to the gripper rather than the world.

0 walks both targets back to their home pose at the same --linear-speed and --angular-speed manual control uses, so the arms return at a speed the operator has already accepted rather than snapping back. Any motion key or gripper key cancels the return and hands control straight back. The grippers are left alone, so an arm carries what it is holding home instead of dropping it on the way.

Esc quits. Every held control stops immediately — a home return too, so the arms stay where they are — and the node shuts down, sending lifter-stop and then quit on the way out; wired into a dora-openarm-quitter tick node's command input (as in the example dataflows), the quit stops the timers so the whole dataflow comes down. Keys only reach the robot while the browser page has focus, and losing focus releases everything held.

By default the page is only reachable from the node's own machine. To operate from another machine, pass --host 0.0.0.0 and open http://<node-host>:8080/ (browsers allow WebRTC on plain HTTP; camera/mic-free pages like this one need no HTTPS).

When the keys do nothing

Check the page: is it open, does its header say connected, and does the tab actually have focus (click the page once)? If Esc was pressed, the node has quit and the dataflow must be started again.

Interface

--linear-speed   translation speed, m/s        (default: 0.05)
--angular-speed  rotation speed, rad/s         (default: 0.5)
--grip-speed     gripper speed, fraction/s     (default: 2.0)
--home-right     right arm home position X Y Z (default: 0.216 -0.1535 -0.22)
--home-left      left arm home position X Y Z  (default: 0.216 0.1535 -0.22)
--home-rpy       home orientation in degrees   (default: 0 -90 0)
--pos-min        lower workspace bound X Y Z   (default: -0.8 -0.8 -0.8)
--pos-max        upper workspace bound X Y Z   (default: 0.8 0.8 0.8)
--host           web server bind address       (default: 127.0.0.1)
--port           web server port               (default: 8080)
--offer          SDP offer (WebRTC-only mode; see below)
--answer-host    host to write the SDP answer to (WebRTC-only mode)
--answer-port    port to write the SDP answer to (WebRTC-only mode)
--connect-timeout  seconds to wait for the browser to connect (default: 60)

The --host and --port defaults can also be overridden with the HOST and PORT environment variables; explicit --host/--port still win.

The home pose defaults are the end-effector poses of the scene's home keyframe, expressed in its arm_origin frame. The IK and MuJoCo nodes start from that same keyframe, so publishing anything else would make IK drag both arms across the workspace on the first tick. After changing scene or keyframe, we need to follow the changes.

WebRTC-only mode

By default the node hosts the page itself. Pass --offer (or set OFFER) to run it as a pure WebRTC peer instead, with no HTTP server: another service hosts index.html/teleop.js and brokers signaling, and this node only runs the robot side of the connection.

• --offer / OFFER — the browser's SDP offer, handed in at startup. Just the bare SDP; the type is always offer.
• --answer-host / ANSWER_HOST (default 127.0.0.1) and --answer-port / ANSWER_PORT — the TCP host and port this node connects to and writes the answer SDP to (then closes). The service listening there wraps it back into an answer and relays it to the browser.

This is a one-shot connection: the offer is fixed at startup, so the node runs that single peer for its whole life; reconnecting means restarting the node. When the browser disconnects — tab closed, network drop — the node exits, since no other browser can ever take its place. --host/--port are ignored in this mode.

After the answer is sent, the node waits up to --connect-timeout / CONNECT_TIMEOUT seconds (default 60) for the browser to connect. If the connection never comes up — nobody applied the answer, or the media path failed — the node exits instead of holding a dead peer, so a supervisor can restart it for a fresh offer.

Quick start

example/dataflow-mujoco.yaml drives both arms in MuJoCo through IK, with no VR headset and no real OpenArm, and streams MuJoCo's ceiling camera back to the browser:

uv run dora build example/dataflow-mujoco.yaml --uv
uv run dora run example/dataflow-mujoco.yaml --uv

Then open http://127.0.0.1:8080/ and click the page, then hold a motion key. The arms hold their startup pose until you press a key. If a physical lifter is in the dataflow, connect the keyboard node's command output to its command input so it is stopped when the node exits.

To record what you teleoperate, use dataflow-keyboard-mujoco.yaml in dora-openarm-data-collection — the same graph with the collection UI and dataset recorder attached.

Development

uv sync
uv run pytest tests

The pose integrator in teleop.py imports neither dora nor the WebRTC stack, so the whole state machine is tested without a dataflow or a browser; tests/test_web.py exercises the WebRTC server end to end in-process.

License

Licensed under the Apache License 2.0. See LICENSE for details.

Copyright 2026 Enactic, Inc.

Code of Conduct

All participation in the OpenArm project is governed by our Code of Conduct.