Auto-assembled, not yet reviewed

HOPEJr

DIY humanoid arm and hand with tendon-driven fingers and LeRobot teleoperation.

Reproducibility53/100Early source coverage, unverifiedCADBOMWIREFWBUILDLICREPHow it is computed
HOPEJr 66-DoF humanoid robot, 3D render from robot.urdf
simplified 3D ยท robot.urdf

About HOPEJr

HOPEJr is a source-available DIY humanoid robot from The Robot Studio, designed by Rob Knight with recent arm and hand work by Martino Russi at Hugging Face. The Hugging Face arm and hand use low-cost Feetech serial-bus servos driving 3D-printed, tendon-actuated fingers with an opposable thumb, while the Humanoid/ folder has been updated for Robstride RS02 motors. Hugging Face announced the full humanoid with 66 degrees of freedom at about $3,000. The Hugging Face revision adds custom PCBs so that no soldering is required, a matching teleoperation exoskeleton with hall-encoder joint tracking, and full LeRobot integration for recording, training and inference. The repo ships STEP and STL files, PCB gerbers and a detailed bill of materials without prices. The 3D view shows only the right leg, not the full humanoid.

Licenses

Hardware
Apache-2.0Humanoid/ folder only; the Arm/ folder has no license file
Software
Not published
Docs
Not published

Degrees of freedom

66 DoF

No per-group breakdown has been sourced yet.

HumanoidTendon-drivenTeleop exoskeletonsource

How to build HOPEJr

5 steps

Steps marked Motari summary condense the linked source; follow the source for exact instructions. Upstream step marks a step taken from the linked guide.

  1. Print the structural parts

    Print the arm, hand, exoskeleton and glove STL sets; STEP files are provided for editing.

    Motari summarygithub.com/TheRobotStudio/HOPEJr

  2. Order the BOM and PCBs

    Source the Feetech servos, driver boards, fasteners and tendon wire from Arm/BOM.md, and fab the custom PCBs from the gerbers.

    Upstream stepgithub.com/TheRobotStudio/HOPEJr/blob/0a60df1e326b092436edfb...

  3. Assemble the arm and hand

    Build the arm and the tendon-driven hand. The latest revision replaces the threaded inserts with bolts and, with the custom PCBs, needs no soldering.

    Motari summarygithub.com/TheRobotStudio/HOPEJr

  4. Build the teleop exoskeleton

    Assemble the matching exoskeleton with hall-encoder joints for 1:1 teleoperation of each robot joint.

    Upstream stepgithub.com/TheRobotStudio/HOPEJr/blob/0a60df1e326b092436edfb...

  5. Run with LeRobot

    Integrate with LeRobot to record demonstrations, train policies, and run inference on HOPEJr.

    Upstream stepgithub.com/TheRobotStudio/HOPEJr/blob/0a60df1e326b092436edfb...
Print timenot published
Assembly timenot published

Wiring, power and firmware are safety-relevant and shown for reference only. Check them against the source before building.

HOPEJr bill of materials

9 rows

Cost to build

$3,000USDestimate
  • announced target price for the full humanoid (secondary report)$3,000estimate

In the source currency, as read on 2026-09-30. Not converted, and not checked against current vendor prices: none of these is a Motari-verified checkout total.

HOPEJr parts, as the source lists them. Prices are the source's, not checked against vendors.

HOPEJr bill of materials
PartQtySpecSourceConfidence
SCS0009 Feetech servomicro serial-bus servo for fingers and thumb
166V, ~2.3 kg-cm
Feetech / Alibaba link from the projectprice not listedSource BOM: Arm/BOM.md line 10
high
STS3215 Feetech 12V servoarm joint servo
412V, ~30 kg-cm, 360 deg
Feetech / Alibaba link from the projectprice not listedSource BOM: Arm/BOM.md line 12
high
STS3250 Feetech servoshoulder yaw and elbow flex
212V, ~50 kg-cm, steel gears
Feetech / Alibaba link from the projectprice not listedSource BOM: Arm/BOM.md line 11
high
SM8512BL Feetech servoshoulder pitch
112V, ~85 kg-cm brushless
Feetech / Alibaba link from the projectprice not listedSource BOM: Arm/BOM.md line 13
high
URT-1 servo bus boardUSB-to-serial arm driver
1Feetech bus interface
AliExpress link from the projectprice not listedSource BOM: Arm/BOM.md line 20
high
Waveshare servo driver boardhand servo driver
1serial-bus servo driver
Waveshare / Amazon / AliExpress links from the projectprice not listedSource BOM: Arm/BOM.md line 21
high
Custom connector PCBs12-connector, 7-connector, and homunculus PCBs
1gerber, BOM, and position files in repo
make yourself / JLCPCB workflowprice not listedSource PCB BOMs: Arm/PCB/12-connector/bom.csv line 2, Arm/PCB/7-connector/bom.csv line 2, Arm/PCB/homunculus_pcb/BOM.csv lines 2-15
high
3D-printed parts setarm, hand, exoskeleton, and glove print files
1STEP and STL source files provided
3D print yourselfprice not listedSource CAD/mesh files in Arm/3dprint and Arm/STEP directories
high
Fasteners, bearings, springs, tendon wire, and misc hardwarescrew/nut sets, bearings, springs, tendon wire, PTFE tube, finger protectors
1assorted hardware the project lists
Amazon / AliExpress links from the projectprice not listedSource BOM: Arm/BOM.md lines 30-68
high

Rows from the source's own parts list 20

Arm/BOM.md@0a60df1markdown

Source rowQtyPrice and vendorLine
SCS0009 Feetech
16
Alibabaalibaba.comno price listed
L10
STS3250 Feetech
2
Alibabaalibaba.comno price listed
L11
STS3215 Feetech 12V
4
Alibabaalibaba.comno price listed
L12
SM8512BL Feetech
1
Alibabaalibaba.comno price listed
L13

Arm/PCB/12-connector/bom.csv@0a60df1csv

Source rowQtyPrice and vendorLine
J1, J10, J11, J12, J2, J3, J4, J5, J6, J7, J8, J9
12
vendor not listedno price listed
L2

Arm/PCB/7-connector/bom.csv@0a60df1csv

Source rowQtyPrice and vendorLine
C722693
7
vendor not listedno price listed
L2

Arm/PCB/homunculus_pcb/BOM.csv@0a60df1csv

Source rowQtyPrice and vendorLine
C1525
16
vendor not listedno price listed
L2
C1_4, C2_2, C3_2, C3
4
vendor not listedno price listed
L3
F1
1
vendor not listedno price listed
L4
C160403
16
vendor not listedno price listed
L5
J1
1
vendor not listedno price listed
L6
R1, R4, R5, R6
4
vendor not listedno price listed
L7
R10_2, R10, R11, R12, R8
5
vendor not listedno price listed
L8
R3
1
vendor not listedno price listed
L9

6 more rows in Arm/PCB/homunculus_pcb/BOM.csv

HOPEJr source files

14 files

Files stay in the upstream repository under their own licenses; these links open them there. The 3D model on this page is Motari's conversion of the file named under Simulation.

HOPEJr in simulation

Robot description files a simulator or CAD tool can load, linked at the commit they were found.

The 3D specimen on this page is converted from Humanoid/URDF/Right_Leg/robot.urdf at 0a60df1.

Builds of HOPEJr

0 reviewed

No reviewed builds of HOPEJr yet.

A build log records the evidence (photos, a video, your repository), what the build cost, how long it took and what you changed. Each one is checked by Motari (until a maintainer claims this page) before it shows here, and reviewed builds count toward the reproducibility score.

Sources and provenance

Sources

Last push to TheRobotStudio/HOPEJr: 2026-05-04 (checked 2026-10-01)

Related links

How this page was made

Assembled from public sources on 2026-06-04, not yet reviewed by the maintainer. Each figure links to where it is stated; a value the sources do not state reads "not published". Last source review: source BOM 0a60df1.

Original files stay intact and separately licensed; Motari adds only the summary on this page. Maintainer? Request a correction or removal.

Badge for the README

Maintain HOPEJr? Show its reproducibility score in the project's README. The badge links back to this page and updates with the score.

Badge: reproducibility 53/100

Markdown
[![Motari reproducibility score for HOPEJr](https://motari.io/api/v1/badge/hopejr)](https://motari.io/r/hopejr)
HTML
<a href="https://motari.io/r/hopejr"><img src="https://motari.io/api/v1/badge/hopejr" alt="Motari reproducibility score for HOPEJr" height="20"></a>

Not fully met yet: bom evidence (partial), wiring diagram (partial), build instructions, oshw-compatible license (partial). The score is read from the project's own sources, so publishing what is missing is what raises it. A score of 90 or more needs a reviewed build. How the score is computed