kscale/zbot · spec sheet

K-Scale Z-Bot (Zeroth Bot) specs

Name: K-Scale Z-Bot (Zeroth Bot)
Brand: K-Scale Labs
Price: 999 USD

Small 3D-printed open-source humanoid (~46 cm, 18 motors) from K-Scale Labs, community-developed as Zeroth Bot; sold as Z-Bot at $999 before K-Scale shut down.

Maker

K-Scale Labs

Class

Humanoid

Status

Orphaned

Availability

DIY build

Country

United States, Palo Alto

Level

L1 Compiled

Media

4 items · credited and licensed

Z-Bot (Zeroth Bot) studio render, three-quarter front view — Studio render of the published URDF, the model's zero pose. Geometry only; colours are the model's own materials.Rendered by Hyperspawn from kscalelabs/zeroth-bot (MIT)license: Hyperspawn rendergithub.com

Z-Bot (Zeroth Bot) studio render, side view — Side view of the same URDF render, the model's zero pose.Rendered by Hyperspawn from kscalelabs/zeroth-bot (MIT)license: Hyperspawn rendergithub.com

Z-Bot small humanoid waving outdoors, orange printed shell — From the zeroth-bot repo.K-Scale Labs (zeroth-bot)license: MITgithub.com

4 s turntable of the URDF studio render.Rendered by Hyperspawn from kscalelabs/zeroth-bot (MIT)license: Hyperspawn rendergithub.com

Specifications

6/12 fields sourced

K-Scale Z-Bot (Zeroth Bot) specifications
Heightspecs.heightCm	46cm
Massspecs.massKg	unsourced
Degrees of freedomspecs.dof	18
Payloadspecs.payloadKg	unsourced
Top speedspecs.speedMps	unsourced
Runtimespecs.runtimeMin	unsourced
Battery capacityspecs.batteryWh	unsourced
Pricespecs.priceUsd	999USD$999 (2025); community BOM from ~$350
Actuatorsspecs.actuators	18 servo motors
Computespecs.compute	unsourced
Sensorsspecs.sensors	cameras, IMU (per press)
Year introducedyear	2025
Licenselicense.hw / .sw / .docs	Hardware: MITSoftware: MIT

Note · K-Scale Labs shut down in Nov 2025; the repositories (zeroth-bot, MIT) remain public and community-maintained. No maintainer can certify it until someone adopts it. github.com/kscalelabs/zbot does not exist; the project repo is zeroth-bot. ksim-gym-zbot and zbot-policy-walking contain train.py/convert.py only (no checkpoints), so policies=false.

Openness

method

90 / 100Open hardware

Artifact	Public	Weight	Points
CADopenness.cad	yes	25	25
Bill of materialsopenness.bom	yes	20	20
Sim model (URDF/MJCF)openness.sim	yes	20	20
Firmwareopenness.firmware	yes	15	15
Softwareopenness.software	yes	10	10
Trained policiesopenness.policies	no	10	0
score = Σ weight × public			90

Build package

v0.1.0 · full guide

BOM lines

Parts (qty)

293

Priced BOM

$125

Fab parts

Print time

—

Material

—

Build steps

Est. assembly

—

Safety steps

Vendors

BOM by category · USD from priced lines

Category	Lines	Qty	USD
Electronics	5	5	45
Power	2	2	36
Sensors	2	2	34
Compute	1	1	10
Fasteners	7	263	—
Cabling	2	3	—
Actuators	1	16	—
Other	1	1	—

Offers in CN · GLOBAL · US from 7 vendors

Subsystems · assembly groups

Group	Steps	Min	Safety
fabrication	2	—	—
legs	3	—	—
torso	1	—	—
arms	2	—	—
electrical	3	—	2
software	1	—	—
bring-up	1	—	1

Fabrication: FDM print ×14

Firmware

Targets: Milk-V Duo S (SG2000) running OpenLCH buildroot image (Zeroth-01 BOM), Raspberry Pi 4B running zbot-os-pi4b / kos-zbot (later K-Scale Z-Bot revision), Feetech STS3250 servos (ID/zero config over serial bus, 1 Mbaud), RP2040-LCD-1.28 head display
Repo: github.com/kscalelabs/kos-zbot
Calibrate: kos-zbot CLI: `kos actuator zero all` (or comma-separated IDs) to zero servos; robot-specific service `kos zbot` loads gains and limits. Actuator IDs used in kos-zbot scripts: 11-14, 21-24 (arms), 31-36, 41-46 (legs), 20 total. Older zeroth-bot tree has Rust bins feetech_calibrate / feetech_change_id / feetech_scan.
Notes: Zeroth-01 path: OpenLCH image from https://github.com/Zeroth-Robotics/OpenLCH-buildroot/releases, SSH over USB gadget 192.168.42.1. K-Scale path: Raspberry Pi OS 64-bit + kos-zbot (Python 3.12), servo UART /dev/ttyAMA5 at 1,000,000 baud, 50 Hz control loop default, BNO055 IMU over I2C, policies in .kinfer format run with `kos zbot infer --model`.

Policies

Z-Bot joystick/velocity walking (RL benchmark template) · ksim (JAX/MuJoCo) + kinfer · github.comPipeline: train.py, then convert.py exports model.kinfer. No weights file in the repo (checked 2026-09-25).
Basic Z-Bot walking policy · ksim + kinfer · github.comconvert.py exports the trained policy to .kinfer.
Standing policy (Zeroth-01, TPU) · PyTorch -> CVITEK TPU (Milk-V) · github.comConverted for the Milk-V TPU with tpu-mlir.
Demo inference (Zeroth-01 first run) · Python SDK · github.comexperiments/ exists in the kscalelabs fork only; upstream zeroth-robotics/zeroth-bot does not (checked 2026-09-25).
Scripted demos: wave, salute; voice conversation · kos-zbot · github.comAlso kos_zbot/scripts/salute.py and the voice conversation module kos_zbot/conversation.

Caveats · stated by the package

K-Scale Labs shut down in November 2025 and refunded preorders. docs.kscale.dev and docs.zeroth.bot did not resolve (DNS failure) on 2026-09-24, so all doc content was read from the GitHub source repos (kscalelabs/docs, zeroth-robotics/docs).
No repo named kscalelabs/zbot exists. The hardware repo is kscalelabs/zeroth-bot (a fork of zeroth-robotics/zeroth-bot, last commit 2025-03-19). The OS/software is kscalelabs/kos-zbot.
The only public BOM is the Zeroth-01 electronics BOM (last updated 2024-11-28, 'not yet finalized') with 16x STS3250 and a Milk-V Duo S. The later K-Scale Z-Bot revision uses a Raspberry Pi 4B and 20 actuator IDs, and no BOM for that revision was found.
The itemised BoM Google Sheet linked from the K-Scale BOM page (1CmScSyjjHeuxxL0QmV3nXdUUqKY3HEEfBCJPlzzbGro) now requires sign-in and could not be read.
The servo price is not current. The BOM says 'Depends by Seller due to Supply Chain Issues. Previously: 222.24' for 16 units, so no unitUsd is given. Other prices are the BOM's 'Total Cost' at qty 1, from late 2024.
The docs say STS3215 servos are too slow for the legs and STS3250 should be used. If you use plastic-housing STS3215s, the housing holes are not tapped and self-tapping screws are needed.
Unlisted items: the 'Milk hat' and 'custom PCBs' mentioned in the assembly doc, the PH-2.0 4-pin cable, the M3x8, M3x12, M3x5, M2x4 and M2x6 screws, and the M3 nuts. These are named in the assembly steps but are not in the fastener table. The Google Doc also says '4 X M10' for the torso-to-hip joint, which looks like a typo for M3x10.
Printing material, print hours and grams are not published.
Step minutes are not published. The assembly doc only notes that order matters for the legs.

Package kscale/zbot@0.1.0 · upstream Zeroth-01 BOM/docs last updated 2024-11-28 (zeroth-robotics/docs@4b8db2311228a445c9d0d6264e02f3a8b102831c); STL set 20241118; K-Scale BOM page kscalelabs/docs@d4ca00ddc760197661d66495d0793b85dd31bea8; kos-zbot@fce28827aad2abfa308576e24a95621b41302a6a · 13 package sources

Models, repositories, links

5 links

URDFgithub.com/kscalelabs/zeroth-bot/blob/main/experiments/teleop/urdf/robot_fixed.urdfmodel
Repogithub.com/kscalelabs/zeroth-botgithub.com
Repogithub.com/kscalelabs/kos-zbotgithub.com
Repogithub.com/kscalelabs/ksim-gym-zbotgithub.com
Repogithub.com/kscalelabs/zbot-policy-walkinggithub.com

News and papers

0 stories · 0 papers

News mentioning Z-Bot (Zeroth Bot)

The news feed is not reachable right now; this page regenerates every 30 minutes.

Papers using Z-Bot (Zeroth Bot)

The papers feed is not reachable right now; this page regenerates every 30 minutes.

Timeline

industry timeline

20251

4 NovCompany
K-Scale Labs shuts down and releases its IP
K-Scale Labs canceled K-Bot orders and refunded deposits after failing to raise funding, and released its intellectual property as open source.
K-Scale Labs K-Scale K-Bot K-Scale Z-Bot (Zeroth Bot)humanoidsdaily.com mikekalil.com

Sources

last checked 2026-09-24

[1]Zeroth Bot repogithub.com/kscalelabs/zeroth-botchecked 2026-09-24
[2]TechEBlog $999 Z-Bottecheblog.com/k-scale-labs-open-source-humanoid-robot/checked 2026-09-24
[3]Humanoids Daily shutdownhumanoidsdaily.com/news/k-scale-labs-cancels-k-bot-orders-open-sources-all-ip-after-funding-failschecked 2026-09-24

Suggest a correction

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Cite this page

humanoidrobots.systems. “K-Scale Z-Bot (Zeroth Bot) specs.” Hyperspawn, data revision 2026-10-08. https://humanoidrobots.systems/kscale/zbot

Machine-readable: /data.json (record kscale/zbot).

Get it · build itDIY build

Listed at $999. Parts from the package BOM: $125 (10/21 lines priced).

Every way to get it Build guide

humanoidrobot.build/get/kscale/zbot

CompanyHumanoid maker

K-Scale Labs

Y Combinator-backed startup that built the open-source K-Bot and Z-Bot humanoids. It shut down in November 2025 after failing to raise more funding, refunding preorders and open-sourcing its work.

HQ: Palo Alto, United States
Founded: —
Funding: not disclosed

Verbs · this robot across the suite

Knowhumanoidrobots.systemshere

Buildhumanoidrobot.buildpartialFiles are public but the maker is gone; uncertified, some parts may need alternates.

Trainhumanoidrobots.trainingliveOnly a fixed-base teleop URDF is in the repo; walking-policy repos are training recipes with no published weights.

Crewhumanoidrobots.teampartial

Maphumanoidrobots.earthpartial

Verification ladderL1

L0Indexed
L1Compiled
L2Sim-verifiedNext: Loads in browser and GPU sim, mass within tolerance of the BOM, holds a stand. Unlocks .training.
L3Sourced
L4Built
L5Certified

Record

id: kscale/zbot
fields: 6/12 sourced
sources: 3
checked: 2026-09-24
revision: 2026-10-08