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HumanoidStanford University2025US

ToddlerBot

Low-cost, fully 3D-printed open-source small humanoid (0.56 m, 3.4 kg, 30 DOF) for scalable policy learning research.

researchDIYL2 Sim-verifiedbuildable

Difficulty index

11.4/13
11.4
Index breakdown
Classhumanoid+5
Cost$5,728 BOM+1.8
DOF30 DOF+3
Parts355 parts+1.6
How the index works

Top of the ladder. This robot lives on the humanoid domains.

Specimen photographs

6 items
  • ToddlerBot studio render, three-quarter front view
    Studio render of the published MJCF, keyframe pose from the model. Geometry only; colours are the model's own materials.Rendered by Hyperspawn from mujoco_menagerie/toddlerbot_2xc (MIT) · Hyperspawn render · source
  • ToddlerBot studio render, side view
    Side view of the same MJCF render, keyframe pose from the model.Rendered by Hyperspawn from mujoco_menagerie/toddlerbot_2xc (MIT) · Hyperspawn render · source
  • 4 s turntable of the MJCF studio render.Rendered by Hyperspawn from mujoco_menagerie/toddlerbot_2xc (MIT) · Hyperspawn render · source
  • Three ToddlerBot humanoids standing side by side with coloured chest panels
    ToddlerBot banner from the project repo.Haochen Shi et al. (ToddlerBot) · MIT · source
  • ToddlerBot: Open-Source ML-Compatible Humanoid Platform for Loco-ManipulationHaochen Shi · official video, embedded · source
  • ToddlerBot 2.0 Arm OverviewHaochen Shi · official video, embedded · source

Spec card

8/13 known
Degrees of freedom
30
Height
56 cm
Mass
3.4 kg
Payload
1.48 kg
BOM total
$5,728 · 46/47 lines priced
Part count
355
Actuators
servo actuators; 7 DOF/arm, 6 DOF/leg, 2 neck, 2 waist
Compute
NVIDIA Jetson Orin NX 16GB

Not in the registry: speed, runtime, battery, price, sensors. Left blank rather than guessed.

What you learn building it

  • +Whole-body control
  • +Dozens of actuators on one bus
  • +Balance and fall handling
  • +Safe bring-up of a full-size machine
  • +FDM 3D printing: 13 parts, about 55 h of printing
  • +Tools used: Bambu Lab printer (recommended; sheet lists X1-Carbon Combo + smooth PEI plate + glue), Electric screwdriver (low torque for M2), PH1 screwdriver, Allen keys, Wrench or pliers, Allen key, Dynamixel Wizard 2.0, U2D2 + U2D2 power hub + 12 V adapter (per the manual; the sheet lists U2D2/hub only under Teleoperation) +6
  • +16 assembly steps across 10 subassemblies
  • +Flashing firmware for Dynamixel X-series servos (Protocol 2.0, TTL, 2 Mbps), TTL power board V8 (CH348L 8-port USB-to-TTL, no MCU firmware), Jetson Orin NX host (JetPack 6.1+, RT kernel)
  • +Testing in simulation (URDF/MJCF) before touching hardware
  • +Running published learned policies

Openness

100/100
  • publicCAD
  • publicBOM
  • publicFirmware
  • publicSim model
  • publicSoftware
  • publicPolicies

Score 100/100 computed from what is public: CAD 25, BOM 20, sim 20, firmware 15, software 10, policies 10. Hardware license: CC-BY-NC-SA-4.0. Software license: MIT.

Repos & models

MJCF ↗MuJoCo Menagerie ↗
SiteDocsVideo

Build it

Has an ORP build package.
Build it on humanoidrobot.build ↗

Simulate

Load it in the browser simulator and train a policy before building.

Open on humanoidrobots.training ↗

Next rung

None. This is the top. Find people building it on humanoidrobots.team.

This is the top of the ladder.

NoteToddlerBot 2.0 released Aug 2025; variants 2XC and 2XM both in Menagerie (toddlerbot_2xm). Onshape CAD + MakerWorld print files + BOM sheet public. Locomotion Beyond Feet follow-up Jan 2026. Mirror fork exists at kscalelabs/toddlerbot. Licenses per README: code and docs MIT; hardware design (Onshape, STL/3MF) CC BY-NC-SA 4.0, non-commercial.

Sources

  1. [1]Official repo (README license section: code MIT, design CC BY-NC-SA 4.0)checked 2026-09-25
  2. [2]arXiv paperchecked 2026-09-24
  3. [3]Project sitechecked 2026-09-24