humanoidrobots.systems

chestnut/aero-hand-open · spec sheet

Chestnut Aero Hand Open specs

Open-source tendon-driven five-finger hand with 7 actuated DOF (16 joints), fully 3D printed, weighing 389 g, with a Python SDK and ROS2 support.

Maker
Chestnut Robotics (formerly TetherIA)
Class
Hand
Status
Active
Availability
Kit
Country
United States
Level
L2 Sim-verified
01

Media

4 items · credited and licensed
Aero Hand Open studio render, three-quarter front viewrender
Studio render of the published MJCF, keyframe pose from the model. Geometry only; colours are the model's own materials.Rendered by Hyperspawn from mujoco_menagerie/tetheria_aero_hand_open (Apache-2.0)license: Hyperspawn rendergithub.com
Aero Hand Open studio render, side viewrender
Side view of the same MJCF render, keyframe pose from the model.Rendered by Hyperspawn from mujoco_menagerie/tetheria_aero_hand_open (Apache-2.0)license: Hyperspawn rendergithub.com
Aero Hand Open in three poses, tendon-driven fingers
Banner from the aero-hand-open repo.Chestnut Robotics (aero-hand-open)license: CC-BY-NC-SA-4.0github.com
4 s turntable of the MJCF studio render.Rendered by Hyperspawn from mujoco_menagerie/tetheria_aero_hand_open (Apache-2.0)license: Hyperspawn rendergithub.com
02

Specifications

4/12 fields sourced
Chestnut Aero Hand Open specifications
Heightspecs.heightCmunsourced
Massspecs.massKg0.39kg
Degrees of freedomspecs.dof7
Payloadspecs.payloadKgunsourced
Top speedspecs.speedMpsunsourced
Runtimespecs.runtimeMinunsourced
Battery capacityspecs.batteryWhunsourced
Pricespecs.priceUsd314USDComplete kit $314
Actuatorsspecs.actuatorsunsourced
Computespecs.computeunsourced
Sensorsspecs.sensorsunsourced
Year introducedyear2025
Licenselicense.hw / .sw / .docsHardware: CC-BY-NC-SA-4.0Software: Apache-2.0

Note · TetherIA rebranded to Chestnut Robotics (GitHub org renamed TetherIA -> Chestnut-Robotics). Design files are non-commercial; commercial manufacturing needs a license.

03

Openness

method
90 / 100Open hardware
ArtifactPublicWeightPoints
CADopenness.cadyes2525
Bill of materialsopenness.bomyes2020
Sim model (URDF/MJCF)openness.simyes2020
Firmwareopenness.firmwareyes1515
Softwareopenness.softwareyes1010
Trained policiesopenness.policiesno100
score = Σ weight × public90
04

Build package

v0.1.0 · full guide
BOM lines
24
Parts (qty)
156
Priced BOM
$324
Fab parts
17
Print time
—
Material
—
Build steps
23
Est. assembly
—
Safety steps
5
Vendors
11

BOM by category · USD from priced lines

CategoryLinesQtyUSD
Actuators17209
Structure43356
Fasteners1010128
Electronics3917
Compute118
Cabling226
Power11—
Other11—
Printed11—

Offers in CN · GLOBAL · US from 11 vendors

Subsystems · assembly groups

GroupStepsMinSafety
Fabrication4——
Fingers2——
Thumb2——
Electronics2—2
Firmware2—1
Actuators2——
Palm6—1
Bring-up1—1
Finishing1——
Policy1——

Fabrication: FDM print ×17

Firmware

Targets
Seeed XIAO ESP32S3 (hand controller, 16-byte binary serial protocol, default 921600 baud), Feetech HLS3606M bus servos, IDs 0-6
Repo
github.com/Chestnut-Robotics/aero-hand-open/tree/main/firmware
Calibrate
Current-based homing on the ESP32 (GUI Homing button or opcode 0x01), then TRIM (0x03) per channel to set the extend endpoint, stored in NVS. CALIBRATE_MID re-centres a channel whose tendon travel falls outside the default single-turn window.
Notes
Prebuilt left/right binaries in firmware/main/bin (v0.1.0 to v0.2.0); flash from `aero-open-gui` or build firmware.ino with LEFT_HAND/RIGHT_HAND set in HandConfig.h. Servo rail is 6 V from its own supply (up to 10 A), separate from USB. Servos over 80 °C may ignore commands until they cool. Torque control closes only (open-to-close direction).

Policies

  • in-hand cube rotation about Z (60 mm, 117 g cube) · MuJoCo Playground PPO, deployed via ROS 2 (rl_z_rotation_deploy) · github.comPretrained checkpoint shipped in the repo; validated against firmware v0.1.0 kept in firmware/main/bin/rl_z_rotation.

Caveats · stated by the package

  • BOM total is $316.48 per hand in USD as stated in BOM.csv (printed parts and silicone are costed by volume, so real filament and silicone purchases cost more). The README quotes a $314 kit.
  • The 6 V servo power supply and XT30 connector appear in the assembly guide but not in BOM.csv; no model or vendor is given. Size it for about 10 A peak per the firmware README.
  • Design files (CAD, STL, BOM, docs) are CC BY-NC-SA 4.0, non-commercial; commercial manufacturing needs a licence from Chestnut Robotics. Firmware and SDK are Apache-2.0.
  • Several BOM links were long search URLs; tracking parameters are stripped here. MISUMI undersized-pin links point at a series page where you select the size.
  • Cable lengths per servo come from a table in the guide that is partly hard to read; only servo 1 (90 mm) and servos 3-5 (140 mm) are stated unambiguously. Check the guide page 10 for servos 2 and 6.
  • The BOM row labels and the guide's part numbers differ (e.g. undersized 2x10 is P/N 37 in the BOM and 32 in the guide).
  • The RL deployment README calls the GUI `aero-hand-gui`; the SDK installs `aero-open-gui`. The README also says `--select-packages`; colcon's flag is `--packages-select`.
  • The BOM lists one undersized 2x20 pin that the guide never calls out by name; this package puts it with the thumb CMC pins. Check the Onshape model.
  • The RL policy was validated only with the archived v0.1.0 firmware, not the newer binaries.
  • Upstream disclaimer: research prototype, not validated for prolonged or heavy-duty use; tendons need periodic re-tensioning.

Package chestnut/aero-hand-open@0.1.0 · upstream Chestnut-Robotics/aero-hand-open@7bb2f23485a7d440960c21046da642de132b7745 (main, 2026-09-15): hardware/Assembly/BOM.csv, Tools.csv, Gen1_OPEN_Assembly_Guide.pdf, firmware/ (bin up to v0.2.0), sdk/ (aero-open-sdk), ros2/; docs.tetheria.ai as of 2026-09-25 · 12 package sources

05

Models, repositories, links

7 links
06

Videos

2 tagged · 0 from the maker's channel
Introducing Aero Hand Open | TetherIA’s First Open-Source Robotic HandChestnutRoboticsOfficial embedyoutube.comChestnut RoboticsChestnut Aero Hand Open
Aero Hand Open Lifts a 5-Gallon Water Jug | Open-Source Robotic Hand Strength Test #roboticsChestnutRoboticsOfficial embedyoutube.comChestnut RoboticsChestnut Aero Hand Open
07

News and papers

0 stories · 0 papers

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08

Sources

last checked 2026-09-24
  1. [1]Aero Hand Open repo (specs, license TL;DR)github.com/Chestnut-Robotics/aero-hand-openchecked 2026-09-24
  2. [2]Rebrand announcementx.com/ChestnutRobotic/status/2032330051707146679checked 2026-09-24
  3. [3]arXiv paperarxiv.org/abs/2608.28578checked 2026-09-24
09

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Cite this page

humanoidrobots.systems. “Chestnut Aero Hand Open specs.” Hyperspawn, data revision 2026-10-08. https://humanoidrobots.systems/chestnut/aero-hand-open

Machine-readable: /data.json (record chestnut/aero-hand-open).