OpenBionics Prosthetic Hands
Based on published sources · Not tested by us ·
License: CC-BY-SA-4.0 (repository-wide statement), LGPL-2.1-or-later (Herkulex library header); sketch covered only by repository-wide CC BY-SA 4.0 statement, CC-BY-SA-4.0 · Details by part
Overview
Single-actuator, tendon-driven anthropomorphic hand design from the OpenBionics initiative, with 3D-printed and laser-cut variants, parametric SolidWorks CAD and a 2015 assembly report; repository-wide CC BY-SA 4.0 statement. [S001] [S003] [S005]
This repository from the OpenBionics initiative publishes a five-finger hand that upstream presents as an affordable prosthetic hand, stating a cost under USD 200 and a weight under 300 g. A whiffletree differential lets a single actuator close all fingers, and locking buttons block each finger independently; the README credits this with 144 different grasps. [S001] The 2015 report gives index to pinky three flexion joints each and the thumb two flexion joints plus a lockable abduction/adduction mechanism. Joints are silicone or polyurethane flexures, and Dyneema tendons in low-friction tubes provide flexion. [S014] Its authors list affiliations at the National Technical University of Athens, Yale and Cornell. [S016]
The design suits makers and researchers studying underactuated, tendon-driven hands. No medical certification or clinical evaluation was identified in the inspected sources, and this catalog makes no safety or medical-suitability assessment.
Specifications
| Detail | Description |
|---|---|
| Type | Five-finger anthropomorphic hand: index to pinky with three flexion DoF each, thumb with two flexion DoF and one lockable abduction/adduction DoF, all driven by a single actuator through a whiffletree differential with per-finger locking buttons. Reported by source [S001] [S014] · Checked 2026-10-05 |
| Intended users | Makers and researchers studying underactuated, tendon-driven hand mechanisms who can 3D print or laser cut parts, stitch flexure joints and edit SolidWorks models Editorial assessment [S006] [S007] [S008] [S010] · Checked 2026-10-05 |
| Assembly | Illustrated 2015 technical report covering finger assembly (rigid phalanges stitched to silicone flexure joints) and hand assembly on the palm. Reported by source [S005] [S010] [S014] · Checked 2026-10-05 |
| Calibration | Not known |
| Operating system | Not known |
| Computer needed | Not known |
3D preview
Preview not available yet. Design-source links are available. A configuration-matched assembly and its file-level reuse scope have not yet been reviewed for a hosted preview.
Model sources
Design-source links are available. A configuration-matched assembly and its file-level reuse scope have not yet been reviewed for a hosted preview.
Assembly and use
Variants to choose between
- 3D-printed: ABS parts printed on a Lulzbot TAZ 4, with about 6 hours of printing reported. [S007]
- Laser-cut: acrylic parts, with about 2 hours of cutting reported. [S008]
- Personalized size: left and right SolidWorks models scale from hand length (182–225 mm) and breadth (82.5–110 mm); editing requires SolidWorks 2014 or later. A FreeCAD migration covers only the palm, differential and thumb. [S006] [S009]
- Experimental options: a molded HDM finger design that relies on an external GrabCAD hand model, and a body-powered harness that upstream prices under USD 25. [S010] [S011]
The reference hand in the report measures 190 × 90 × 62.5 mm and weighs 300 g. [S014]
What a build involves
The parts list names one HerkuleX DRS-0201 servo as the actuator. [S015] The report's experiments drove it from an Arduino Micro through a custom board. The repository's breakout board (Arduino Micro Pro, with analog inputs for sensors such as EMG) is described as "currently under testing". [S012] [S014] The firmware is a simple sketch using a modified Herkulex library. [S013] Assembly involves stitching rigid phalanges to silicone sheets with needles and fishing line, using hand tools such as long-nose pliers, an M3 wrench and a 2.5 mm Allen key. [S010] [S015] A separate OpenBionics ROS package mentioned in the report was not inspected. [S014]
Cost
The 2015 report lists "less than 200 USD" alongside its 190 mm reference hand, but gives no itemized prices or pricing date, so the figure is historical context rather than a current build budget. [S001] [S014]
What the repository contains and how it is licensed
The pinned tree holds SolidWorks parts and assemblies with STL and DXF exports, Eagle files for the breakout board, the Arduino sketch and Herkulex library, two MATLAB kinematics scripts that use a robotics toolbox, and the assembly report. [S001] [S004] LICENSE.txt places "this work" under CC BY-SA 4.0 without separate terms per folder, so that statement is the only license identified for the CAD, board files, sketch and MATLAB scripts; the report repeats it. Distributed adaptations must keep the same license. [S003] [S016] The bundled Herkulex library is third-party code whose header states LGPL 2.1 or later. [S013] Terms for the external GrabCAD model used by the HDM variant were not reviewed. [S010]
What remains unknown
The inspected default-branch snapshot dates to 2018-02-10, and no stable release was found among the repository's published releases. The full repository archive exceeds this catalog's 150 MiB intake limit, so CAD, STL, board files and the report PDF were listed but not preserved or checked. [S002] [S004] No fabrication, assembly or test was performed.
Cost
No current, complete configuration-specific build cost has been established for this profile.
Source files and licenses
Complete mechanical, electronics, firmware and assembly sources are published with a repository-wide CC BY-SA 4.0 statement and a separately noticed LGPL library. Included as a historical hand design; inclusion is not a medical-suitability or certification claim.
| Layer | Availability / license |
|---|---|
| mechanical design | available · CC-BY-SA-4.0 (repository-wide statement) SolidWorks parts and assemblies, STL (left and right) and DXF laser files listed in the pinned tree; payloads not preserved or geometry-checked. The HDM finger variant depends on an external GrabCAD model whose terms were not reviewed. [S003] [S004] [S006] [S007] [S008] |
| electronics | available · CC-BY-SA-4.0 (repository-wide statement) Eagle-format breakout board (uC_Board.sch/.brd) listed; described upstream as under testing. Covered only by the repository-wide statement. [S003] [S004] [S012] |
| firmware | available · LGPL-2.1-or-later (Herkulex library header); sketch covered only by repository-wide CC BY-SA 4.0 statement Modified third-party Herkulex library by Alessandro Giacomel carries its own LGPL notice; the HerkulexSerial sketch has no separate license notice in inspected sources. [S003] [S013] |
| software | available · CC-BY-SA-4.0 (repository-wide statement) Two MATLAB kinematics scripts; the robotics toolbox they use is a separate dependency. The ROS package mentioned in the report lives outside this repository and was not inspected. [S001] [S003] [S004] |
| documentation | available · CC-BY-SA-4.0 The report source states CC BY-SA 4.0 explicitly; the compiled PDF was listed but not preserved. [S003] [S005] [S016] |
Mechanical hand design; no learned model.
No dataset is part of the design release.
References
Links identify the documentation and revisions used in this profile. Access dates record when each source was retrieved.
- S001 · OpenBionics initiative / project contributors
Prosthetic-Hands README
Accessed 2026-10-05 · README.md at master commit snapshotSource notes
States cost under USD 200, weight under 300 g, single-actuator differential, parametric personalization and repository contents.
- S002 · OpenBionics initiative / project contributors
Repository revision and acquisition metadata
Accessed 2026-10-05 · 639aca3a53c682d00c5a10d9c96e47c74e04a57c (default-branch snapshot; no stable release); GitHub API metadataSource notes
Commit date 2018-02-10; full archive blocked by the 150 MiB intake limit; dated popularity counts.
- S003 · OpenBionics initiative / project contributors
Repository license statement
Accessed 2026-10-05 · LICENSE.txtSource notes
States the work is licensed under Creative Commons Attribution-ShareAlike 4.0 International.
- S004 · OpenBionics initiative / project contributors
Pinned repository file tree
Accessed 2026-10-05 · GitHub git trees API (recursive) at the pinned commit; selected pathsSource notes
Lists SolidWorks sources, STL and DXF files, Eagle board files, Arduino code, MATLAB kinematics and the assembly-guide PDF.
- S005 · OpenBionics initiative / project contributors
Assembly guide overview
Accessed 2026-10-05 · Assembly Guide/README.mdSource notes
Technical report as step-by-step replication tutorial; hand design summary and references.
- S006 · OpenBionics initiative / project contributors
Parametric 3D design guide
Accessed 2026-10-05 · CAD/3D Design/README.mdSource notes
Personalization via hand length and breadth parameters in SolidWorks 2014 or later; supported hand-size range.
- S007 · OpenBionics initiative / project contributors
3D-printed parts notes
Accessed 2026-10-05 · CAD/3dPrintedParts/README.mdSource notes
ABS on a Lulzbot TAZ 4; about 6 hours fabrication time.
- S008 · OpenBionics initiative / project contributors
Laser-cutter files notes
Accessed 2026-10-05 · CAD/Laser/README.mdSource notes
Acrylic (Plexiglas) laser-cut version; about 2 hours fabrication time.
- S009 · OpenBionics initiative / project contributors
FreeCAD migration notes
Accessed 2026-10-05 · CAD/FreeCAD/README.mdSource notes
Partial FreeCAD migration (palm, differential, thumb); fingers to follow.
- S010 · OpenBionics initiative / project contributors
HDM finger design notes
Accessed 2026-10-05 · CAD/HDMDesign/README.mdSource notes
Alternative hybrid-deposition finger design relying on an external GrabCAD human-hand model; original fingers use silicone sheets stitched with needles.
- S011 · OpenBionics initiative / project contributors
Body-powered harness notes
Accessed 2026-10-05 · CAD/BodyHarness/README.mdSource notes
Optional body-powered harness; upstream cost under USD 25 and 250 g.
- S012 · OpenBionics initiative / project contributors
Electronics breakout board notes
Accessed 2026-10-05 · Electronics/README.mdSource notes
Breakout board for servo control with analog/digital inputs and I2C; Arduino Micro Pro (ATmega32U4); board under testing.
- S013 · OpenBionics initiative / project contributors
Arduino firmware notes and Herkulex library header
Accessed 2026-10-05 · Software/README.md; Software/libraries/Herkulex/Herkulex.h headerSource notes
Simple Arduino firmware using a modified third-party Herkulex DRS-0201 library whose header states LGPL 2.1 or later.
- S014 · OpenBionics initiative / project contributors
Assembly guide technical report: design and results
Accessed 2026-10-05 · Assembly Guide/tex/Description.tex (2015 report source)Source notes
Finger DoF and flexure joints, tendon routing, reference hand dimensions, cost and weight table, experiment setup.
- S015 · OpenBionics initiative / project contributors
Assembly guide technical report: tools and parts
Accessed 2026-10-05 · Assembly Guide/tex/Appendix1.tex and Appendix2.texSource notes
Tools and materials boards; auxiliary parts list including one HerkuleX DRS-0201 actuator.
- S016 · OpenBionics initiative / project contributors
Assembly guide technical report: title and license page
Accessed 2026-10-05 · Assembly Guide/tex/OpenBionics_ProstheticHandsGuide2015.texSource notes
Report title, CC BY-SA 4.0 statement and author affiliations (NTUA Control Systems Lab, Yale, Cornell).
Correction guidance · Discussion is not enabled · Profile format 0.7.0-draft.5
Change history
2026-10-05 — Initial intake from the Growbotics comparison lead; verified against the upstream repository at the pinned commit.