Moss v1
Early low-cost leader/follower arm pair built from Feetech STS3215 servos, with five joints plus a gripper. It preceded the SO-100. Its maker now recommends the SO-100 for LeRobot, and its LeRobot support existed only on the main branch.
open hardware · Apache-2.0LeRobot removedverified 2026-10-24aka Moss, Moss arm, moss-robot-arms, moss
Not in the main matrix. It was never in a LeRobot release. The `moss` type existed only on main, from Oct 2024 until the Hardware API redesign of June 2025. There are no Moss datasets or checkpoints in the lerobot Hub org, and the maker recommends the SO-100 instead.
Policies on Moss v1 1 with evidence · 0 unknown
| Policy | State | Tier | Verified | Detail |
|---|---|---|---|---|
| ACT Imitation | works with caveats | T1 · upstream documented | 2026-10-24 1d ago | LeRobot's `moss` robot type and its tutorial were removed in the hardware API redesign (PR #777, June 2025); Moss v1 is not supported by LeRobot v0.6.1, so the documented workflow needs a pre-redesign commit. |
Specifications
- Degrees of freedom
- 5 (Six STS3215 per arm: shoulder_pan, shoulder_lift, elbow_flex, wrist_flex, wrist_roll + gripper.)src
- Arms
- 1
- Actuators
- Feetech STS3215 (6 per arm)src
- BOM / build
- github.com/jess-moss/moss-robot-arms
- Homepage
- github.com/jess-moss/moss-robot-arms
Framework support
| Framework | Support | Since | Type string | Docs |
|---|---|---|---|---|
| LeRobot | removedsrc | — | moss | — |
| LeRobot: main-only: added with SO-100 in PR #419 (merged 2024-10-25) and dropped in the Hardware API redesign (PR #777, merged 2025-06-05). No PyPI release fell between 0.1.0 (2024-03-09) and 0.3.2 (2025-08-01), and v0.3.2 has no moss module, so `since`/`until` are left blank because no released version ever contained it. | ||||
Sources
- T1 · upstream documentedsource-codesource 2025-06-05verified 2026-10-24 (1d ago)
main just before the Hardware API redesign registered a `moss` robot type with six sts3215 motors per arm.
“@RobotConfig.register_subclass("moss") @dataclass class MossRobotConfig(ManipulatorRobotConfig): calibration_dir: str = ".cache/calibration/moss"”
https://github.com/huggingface/lerobot/blob/b536f47e3ff8c3b340fc5efa52f0ece0a7212a57/lerobot/common/robot_devices/robots/configs.py - T1 · upstream documentedrelease-notessource 2025-08-01verified 2026-10-24 (1d ago)lerobot 0.3.2
First tagged release notes list both the PR that added Moss and the redesign that removed it.
“Hardware API redesign by @aliberts in https://github.com/huggingface/lerobot/pull/777”
https://github.com/huggingface/lerobot/releases/tag/v0.3.2 - T1 · upstream documentedvendor-docsverified 2026-10-24 (1d ago)
Maker recommends SO100 for LeRobot; Moss v1 'will be deprecated'.
“While the Moss v1 robot is still supported, it will be deprecated.”
https://github.com/jess-moss/moss-robot-arms/blob/da15b56f01e94e62ca08d14f42e14b8627a240dc/README.md