Auto-assembled, not yet reviewed

Koch v1.1

Low-cost 6-DoF leader/follower arm, an improved Alexander Koch design.

Dormant. No upstream changes for two years or more. It may still build, but parts, firmware and docs may have drifted.

Last push to jess-moss/koch-v1-1: 2024-09-17 (GitHub, checked 2026-10-01).

Repository activity

Reproducibility89/100Strong source coverage, unverifiedCADBOMWIREFWBUILDLICREPHow it is computed
Koch v1.1 open-source 6-DoF robot arm, 3D render from Follower_Arm.STEP
main assembly 3D · Follower_Arm.STEP

About Koch v1.1

Koch v1.1 is an improved version of Alexander Koch's low-cost robot arm, refined for easier assembly with no soldering required. It is a teleoperated leader and follower pair built around Dynamixel XL-series servos and integrates with the LeRobot library. The 3D view shows both arms from the upstream STEP assemblies. The README publishes separate leader and follower BOM tables that add up to $477 at the listed US prices.

Licenses

Hardware
Apache-2.0
Software
Not published
Docs
Not published

Degrees of freedom

6 DoF arm 5gripper 1

Breakdown source

Serial armLeader-follower pairsource

How to build Koch v1.1

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

    STL files provided for leader and follower arms. SolidWorks CAD models are included for modification.

    Motari summaryhuggingface.co/docs/lerobot/koch

  2. ID and configure servos

    Set unique IDs for the Dynamixel XL servos using the Waveshare driver board.

    Motari summaryhuggingface.co/docs/lerobot/koch

  3. Assemble the arms

    Assemble both arms following the upstream assembly video and SolidWorks animations. Version 1.1 needs no soldering and adds a leader arm platform, fastened to the leader base with four M2x5 screws and M2 nuts.

    Motari summaryhuggingface.co/docs/lerobot/koch

  4. Wire power and data

    Wire the leader (5V) and follower (12V with voltage reducer) per the included wiring diagram.

    Upstream stepgithub.com/jess-moss/koch-v1-1/blob/1a553e1fa7d5404b51bbd83b...

  5. Calibrate and teleoperate

    Run calibration and drive the follower from the leader arm.

    Motari summaryhuggingface.co/docs/lerobot/koch
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.

Koch v1.1 bill of materials

14 rows

Cost to build

$477USDsource total

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.

Koch v1.1 parts, as the source lists them. Prices are the source's, not checked against vendors.

Koch v1.1 bill of materials
PartQtySpecSourceConfidence
Dynamixel XL330-M077-T servoLeader BOM
6leader arm smart serial servos; $24 each in US BOM
vendors in the project's README$144Leader BOM; README lines 28
high
Dynamixel XL430-W250-T servoFollower BOM
2follower base smart serial servos; $50 each in US BOM
vendors in the project's README$100Follower BOM; README lines 47
high
Dynamixel XL330-M288-T servoFollower BOM
4follower distal smart serial servos; $24 each in US BOM
vendors in the project's README$96Follower BOM; README lines 48
high
XL330 frame and idler wheel 4pcs setLeader and follower BOM
2one set for leader and one set for follower; $10 each in US BOM
ROBOTIS$20Leader and follower BOM; README lines 29,49
high
XL430 idler wheel setFollower BOM
1follower hardware set; $7 in US BOM
ROBOTIS$7Follower BOM; README lines 50
high
Waveshare Serial Bus Servo Driver BoardLeader and follower BOM
2one per arm; $10 each in US BOM
Waveshare$20Leader and follower BOM; README lines 30,51
high
5V power supplyLeader BOM
1leader power supply; $6 in US BOM
vendors in the project's README$6Leader BOM; README lines 31
high
12V power supplyFollower BOM
1follower power supply; $12 in US BOM
vendors in the project's README$12Follower BOM; README lines 53
high
Voltage reducerFollower BOM
1follower voltage reducer; $14 in US BOM
vendors in the project's README$14Follower BOM; README lines 52
high
Jumper wires 3x40 pcs setLeader and follower BOM
2one set per arm in source tables; $7 each in US BOM
vendors in the project's README$14Leader and follower BOM; README lines 32,54
high
Table clampLeader and follower BOM
2one clamp per arm in source tables; $6 each in US BOM
vendors in the project's README$12Leader and follower BOM; README lines 33,55
high
1.5 mm star/cruciform screwdriver 2pcs setLeader and follower BOM
2tool row appears in both source tables; $7 each in US BOM
vendors in the project's README$14Leader and follower BOM; README lines 35,57
high
USB C-A or C-C 2pcs cable setLeader and follower BOM
2USB cable row appears in both source tables; $9 each in US BOM
vendors in the project's README$18Leader and follower BOM; README lines 36,58
high
3D-printed structural partsprintable STL files provided for leader and follower arms; local filament cost is not part of the README $477 total
1leader and follower printed parts from hardware/*/STL
3D print yourselfnot included in source totalPrintable source files present; no source filament price found
high

Rows from the source's own parts list 21

README.md@1a553e1markdown

Source rowQtyPrice and vendorLine
Dynamixel XL330-M077-T
6
RobotisMyBotShop$24
L28
XL330 Frame and Idler Wheel 4pcs set
1
RobotisMyBotShop$10
L29
Waveshare Serial Bus Servo Driver Board
1
AmazonEckstein$10
L30
5V Power Supply
1
AmazonTaoBao$6
L31
Jumper Wires 3*40 pcs set (M-M, M-F, F-F)
1
AmazonTaoBao$7
L32
Table Clamp
1
AmazonTaoBao$6
L33
Table Clamp 4pcs set
1
Amazonamazon.frn/a
L34
1.5mm Star/Cruciform Screwdriver 2pcs set
1
AmazonTaoBao$7
L35

13 more rows in README.md

Koch v1.1 source files

10 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.

Koch v1.1 in simulation

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

No URDF, MJCF, SDF, USD or Onshape model has been found in the sources.

The 3D specimen on this page is converted from hardware/follower/STEP/Follower_Arm.STEP at 1a553e1.

Builds of Koch v1.1

0 reviewed

No reviewed builds of Koch v1.1 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 jess-moss/koch-v1-1: 2024-09-17 (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: 2026-06-07 source README BOM total; vendor prices not checkout-reconciled.

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 Koch v1.1? Show its reproducibility score in the project's README. The badge links back to this page and updates with the score.

Badge: reproducibility 89/100

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A score of 90 or more needs a reviewed build. How the score is computed