How to build Moss v1 Robot Arms
6-DoF desktop robot arm · Beginner
Build Jess Moss's Moss v1 teleop arms: 12 Feetech STS3215 servos, metal brackets and Waveshare adapters for LeRobot. Now superseded by the SO-100 design.
Mostly printed parts and plug-in servos. Good first build.
Our estimate, part-time
Project's own total, source currency
Apache-2.0
What is Moss v1 Robot Arms?
Moss v1 is a pair of affordable, quick-to-assemble arms by Jess Moss for leader-follower teleoperation in LeRobot. It was among the first designs to swap expensive Dynamixels for the inexpensive Feetech STS3215, which costs about $14.
The project now points new builders to the SO-100 and expects Moss to be deprecated. Both use STS3215s, so you can rebuild a Moss as an SO-100 using the same motors.
Versions and forks
- SO-100 / SO-101
Moss v1 Robot Arms specifications
- DoF
- 6 per arm
- Servos
- Feetech STS3215 × 6 per arm
- Brackets
- Metal STS3215 brackets
- Interface
- Waveshare bus servo adapter
- Software
- LeRobot
Figures as published by the project. See Sources below.
Bill of materials
| Part | Qty | Notes |
|---|---|---|
| Feetech STS3215 | 12 | ≈$14 each |
| Waveshare bus servo adapter | 2 | |
| Metal bracket sets | — | |
| USB-C cables | 2 | |
| Power supplies | 2 | |
| 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 $288 as a ballpark from the project. Start at the project repository.
Tools you'll need
- 3D printer
- Small screwdrivers
Step-by-step build overview
Electronics & wiring overview
Each arm has one STS3215 bus into a Waveshare adapter and its own power supply.
Software
LeRobot's Feetech driver, using the same workflow as the SO-100.
Tips from the bench
- ☕ Starting fresh? The project recommends building the SO-101.
- ☕ Reuse the motors in an SO-100 rebuild.
Moss v1 Robot Arms FAQ
Moss or SO-100?
The Moss README recommends the SO-100.
Which servos does Moss use?
Feetech STS3215s, six per arm.
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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