How to build Koch v1.1
6-DoF desktop robot arm · Intermediate
Build Koch v1.1, Jess Moss's refinement of Alexander Koch's Dynamixel leader-follower arm for LeRobot: $199 leader plus $278 follower in US parts, no soldering.
Some soldering, calibration and Linux comfort needed.
Our estimate, part-time
$199 leader + $278 follower (US, README)
Apache-2.0
What is Koch v1.1?
Koch v1.1 is Jess Moss's refined version of Alexander Koch's low-cost robot arm. It was one of the first affordable leader-follower setups for imitation learning with Hugging Face's LeRobot: you move the small leader by hand and the follower copies it.
Version 1.1 fixed screw interferences, standardised hole sizes, stopped screws going into plastic, raised the follower so it can reach the table, and swapped the DC converter so you don't need to solder or adjust voltages. It also added SolidWorks models, a wiring diagram and animated assembly videos.
Versions and forks
- Koch v1.0 by Alexander Koch
- SO-100/SO-101
Koch v1.1 specifications
- DoF
- 6 per arm (5 joints + gripper)
- Leader servos
- 6 × Dynamixel XL330-M077
- Follower servos
- Dynamixel XL430/XL330 mix
- Software
- LeRobot
Figures as published by the project. See Sources below.
Bill of materials
| Part | Qty | Notes |
|---|---|---|
| Dynamixel XL330-M077 | 6 | Leader |
| Dynamixel follower servos | — | Per the README table |
| Servo driver board | 1 per arm | |
| Power supply and converter | — | |
| Clamps | 1 set per arm | |
| 3D-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 $477 as a ballpark from the project. Start at the project repository.
Tools you'll need
- 3D printer (0.2 mm layers, 0.4 mm nozzle)
- Small hex keys
- LeRobot
- No soldering iron
Step-by-step build overview
Electronics & wiring overview
Each arm is one Dynamixel chain to its own USB board. Version 1.1's fixed converter replaces the solder-and-trim step from v1.0.
Software
LeRobot handles setup, calibration, teleop, recording and training.
Tips from the bench
- ☕ The XL330-M077 (leader) and XL330-M288 (follower) look identical, so label them.
- ☕ Clamp both arms down firmly.
- ☕ The SO-101 is a cheaper alternative.
Koch v1.1 FAQ
How much does Koch v1.1 cost?
$199 for the leader and $278 for the follower in the README's US tables.
Do I need to solder?
No.
Is it supported by LeRobot?
Yes.
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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