Open Source Leg

Based on published sources · Not tested by us · Sources checked 2026-10-01

Overview

Modular knee-and-ankle research platform with published assembly documentation, externally hosted design downloads and a separately licensed Python SDK. [S001] [S005] [S006]

Open Source Leg is a research platform that can be built as a knee, an ankle, or a combined system, with or without series elasticity. Its physical design, purchased actuators, electronics and Python SDK are separate parts of the evidence. Installing the SDK does not establish that a leg has been built, calibrated or qualified for use by a person. [S001] [S005] [S006]

Official website · Source code

Specifications

Detail	Description
Type	Modular powered knee and ankle research platform Reported by source [S005] · Checked 2026-10-01
Intended users	Research laboratories with mechanical fabrication and embedded control experience Editorial assessment [S001] · Checked 2026-10-01
Assembly	Not known
Calibration	Belt adjustment and manual range inspection are documented; encoder address and wiring diagrams remain unverified in this review. Reported by source [S010] [S011] [S012] · Checked 2026-10-01
Operating system	Not known
Computer needed	Raspberry Pi in assembly guides; newer CM5 interface board described separately Reported by source [S007] [S009] [S010] · Checked 2026-10-01

3D preview

Preview not available yet. A model has not yet been prepared and approved for display on this page. This does not mean the project lacks CAD files; see Source files and licenses for the reviewed source availability.

Assembly and use

Choose a configuration before using the BOM

The hardware page describes version 2's single-stage external belt transmission and shared knee/ankle drivetrain design. The referenced BOM names Dephy Actpack 4.1 actuators with 9:1 gearing, batteries, docks, encoders, machined components and stock hardware. Its foot sizes are alternatives, and several fastener packs are explicitly shared between knee and ankle orders. Spare-part recommendations should not be confused with installed quantities. [S005] [S008]

The load cell and strain amplifier are optional in that BOM. An LED component is marked no longer in production, so even a faithful parts-list copy needs substitution review. The newer electronics page describes a Raspberry Pi Compute Module 5 carrier; that description should not silently replace the Raspberry Pi wiring assumptions in the assembly tutorials. [S007] [S008] [S009] [S010]

The listed price is a planning reference

The hardware page gives an approximate $10,500–$23,000 range and a separate itemized total of $23,100. These are upstream estimates with configuration differences, not a fresh delivered quote. The BOM also contains quote-dependent actuators and optional sensing. Machining, the selected foot, shipping, tax, tools and integration work need their own scope before a complete budget can be stated. No current checkout total was verified. [S005] [S008]

Assembly text is available, but diagrams still matter

The instructions cover bearings, aligned pulley subassemblies, housings, actuator attachment and foot mounting. They describe tight fits and alignment requirements; this review did not inspect CAD geometry or test fabrication tolerances. The official downloads page links STEP/drawing archives and an Onshape document. Retrieval of the linked knee archive failed with HTTP 403 in this review, so archive completeness and its exact hardware license remain unverified. A failed retrieval is not evidence that the design is closed. [S006] [S013] [S014] [S015] [S016]

Belt maintenance uses eccentric-cap adjustment followed by manual range, tracking and binding checks. The reviewed pages do not supply a numerical pretension or tightening-torque target. The electronics steps depend on diagrams for the load-cell connections, a horizontally flipped ribbon-cable pinout and encoder address options. Those diagrams were not inspected, so this profile does not reproduce a supposedly verified wiring map. [S009] [S010] [S011] [S012]

Match Python and hardware interfaces explicitly

The preserved SDK README says version 3.3.0 onward requires Python 3.11 or newer, points Python 3.9 users to version 3.2.1, and explicitly excludes Python 3.10. It also offers hardware-specific installation extras. These version-specific statements are more useful than treating the platform name as a single compatible software environment. No package was installed or connected to an actuator here. [S001]

The SDK's own interface table distinguishes complete, partial and unavailable hardware tests and benchmarks across Dephy, moteus and TMotor support. Those are maintainer-reported statuses, not tests performed for this catalog. A supported class name alone does not qualify an arbitrary actuator, firmware revision or complete leg configuration. [S001]

Openness is assessed by layer

The SDK includes LGPL version 2.1 terms. That software license does not establish the hardware archive's license or the availability of purchased actuator firmware. The current review establishes official build documentation, a readable BOM and SDK sources, while leaving mechanical-download contents, electronics design files and exact hardware reuse terms unresolved. No manufacturing, wiring, calibration, walking or human-use testing was performed. [S003] [S005] [S006] [S007] [S008]

Cost

No current, complete configuration-specific build cost has been established for this profile.

Source files and licenses

Available project sources support research coverage; complete build and commercial qualification remain separate.

Layer	Availability / license
mechanical design	available · License not fully assessed Official design downloads and Onshape links exist, but linked knee archive retrieval returned HTTP403. Archive contents, geometry and exact hardware license not verified. [S005] [S006]
electronics	not found · License not fully assessed Wiring text and board descriptions available; complete board design files and license not established in inspected sources. [S007] [S009] [S010]
firmware	not found · License not fully assessed SDK interfaces with purchased actuators; corresponding actuator firmware source/license not established by this review. [S001] [S008]
software	available · LGPL-2.1 Python SDK license only; does not establish rights for hardware designs or purchased actuator firmware. [S001] [S003] [S004]
documentation	available · License not fully assessed Assembly text reviewed; website text and media reuse terms not established. [S005] [S009] [S010] [S011] [S012] [S013] [S014]

Selected mechanical platform and direct SDK-interface scope does not depend on a particular learned policy or dataset.

References

Links identify the documentation and revisions used in this profile. Access dates record when each source was retrieved.

S001 · neurobionics / project contributors
Upstream project overview
Accessed 2026-10-01 · README.md
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S002 · neurobionics / project contributors
Repository revision and release metadata
Accessed 2026-10-01 · 31e2743fd801efd8941894a2b023424dc3520f3e
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S003 · neurobionics / project contributors
Repository license
Accessed 2026-10-01 · LICENSE
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S004 · neurobionics / project contributors
Pinned repository artifact inventory
Accessed 2026-10-01 · 31e2743fd801efd8941894a2b023424dc3520f3e archive file inventory
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S005 · neurobionics / project contributors
hardware
Accessed 2026-10-01 · Preserved official text; BOM readable extraction does not preserve workbook topology or hyperlink targets
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S006 · neurobionics / project contributors
downloads
Accessed 2026-10-01 · Preserved official text; BOM readable extraction does not preserve workbook topology or hyperlink targets
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S007 · neurobionics / project contributors
electronics
Accessed 2026-10-01 · Preserved official text; BOM readable extraction does not preserve workbook topology or hyperlink targets
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S008 · neurobionics / project contributors
bom-readable
Accessed 2026-10-01 · Preserved official text; BOM readable extraction does not preserve workbook topology or hyperlink targets
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S009 · neurobionics / project contributors
electronics assembly step 1
Accessed 2026-10-01 · Text instructions only; diagrams not inspected
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S010 · neurobionics / project contributors
electronics assembly step 2
Accessed 2026-10-01 · Text instructions only; diagrams not inspected
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S011 · neurobionics / project contributors
belt assembly step 2
Accessed 2026-10-01 · Text instructions only; diagrams not inspected
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S012 · neurobionics / project contributors
belt assembly step 3
Accessed 2026-10-01 · Text instructions only; diagrams not inspected
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S013 · neurobionics / project contributors
knee assembly step 1
Accessed 2026-10-01 · Text instructions only; diagrams not inspected
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S014 · neurobionics / project contributors
ankle assembly step 7
Accessed 2026-10-01 · Text instructions only; diagrams not inspected
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S015 · neurobionics / project contributors
knee assembly step 6
Accessed 2026-10-01 · Text instructions only; diagrams not inspected
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.
S016 · neurobionics / project contributors
knee assembly step 3
Accessed 2026-10-01 · Text instructions only; diagrams not inspected
Source notes
Source text inspected for the cited scoped claims; see profile claim notes.

Research and review details

Source research only; no installation, physical build or performance test performed. No affiliate links added.

Profile edited 2026-10-01 · Sources checked 2026-10-01 · Next review target 2026-10-31

Revision: 31e2743fd801efd8941894a2b023424dc3520f3e (release opensourceleg-v3.5.0). Combined hardware and software repository activity recorded 2026-02-02 [S002]

Correction guidance · Discussion is not enabled · Profile format 0.6.0-draft.1

Change history