How to build HOPEJr
66-DoF humanoid robot · Expert
Build HOPEJr from The Robot Studio and Hugging Face: a Feetech-servo arm with a tendon-driven hand, teleop exoskeleton and LeRobot integration.
Research-grade: machining, motor drivers and control theory.
Our estimate, part-time
≈$3,000 was the announced target for the full humanoid, not a published BOM total
Apache-2.0 (Humanoid folder)
What is HOPEJr?
HOPEJr is The Robot Studio's DIY humanoid, designed by Rob Knight, with recent arm and hand work done alongside Hugging Face. When Hugging Face announced it, they described a 66-DoF humanoid targeted at about $3,000.
What you can build from the repo today is mainly the arm and hand. Sixteen Feetech SCS0009 micro servos pull tendons for the fingers and opposable thumb, and larger STS servos move the shoulder and elbow. The Humanoid folder has been updated for Robstride RS02 motors.
The Hugging Face revision added custom PCBs so you don't need to solder, plus a matching exoskeleton with hall-effect encoders that lets you teleoperate the arm. Everything plugs into LeRobot for recording, training and inference.
HOPEJr specifications
- Hand
- 16× Feetech SCS0009, tendon-driven
- Arm
- STS3215, STS3250 and SM8512BL servos
- Teleop
- Hall-encoder exoskeleton
- Software
- LeRobot
- Full humanoid
- 66 DoF (announced)
Figures as published by the project. See Sources below.
Bill of materials
| Part | Qty | Notes |
|---|---|---|
| Feetech SCS0009 servo | 16 | Fingers and thumb |
| Feetech STS3215 12 V servo | 4 | |
| Feetech STS3250 servo | 2 | |
| Feetech SM8512BL brushless servo | 1 | Shoulder pitch |
| URT-1 bus board and Waveshare servo driver | 1 each | |
| Custom connector PCBs and printed parts | — |
Where's the full bill of materials?
The full BOM, with exact quantities and vendors, lives in the project's own files. Prices change often, so treat $3,000 as a ballpark from the project. Start at the project repository.
Tools you'll need
- FDM printer
- Hex drivers
- PC running LeRobot
Step-by-step build overview
Electronics & wiring overview
Arm servos run off the URT-1 bus board and hand servos off a Waveshare driver, both over USB to the PC. The connector PCBs replace hand-soldered joints.
Software
LeRobot handles calibration, teleoperation, dataset recording and policy inference for the arm and hand.
Tips from the bench
- ☕ Tension tendons with the fingers fully extended.
- ☕ Check which repo folder you're in: the Arm and Humanoid folders have different licences.
HOPEJr FAQ
How much does HOPEJr cost?
Hugging Face announced the full humanoid at about $3,000. The repo doesn't publish a costed BOM.
Can I build the whole humanoid now?
The arm, hand and exoskeleton are the most complete parts; the full humanoid files are still evolving.
What's the license?
The Humanoid folder is Apache-2.0. The Arm folder has no licence file.
Sources
Written by Bots n' Beans from the project's own documentation. Check the sources for the latest revision before you buy parts.
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