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mjbots quad, photo from its repository
Photo@mjbots (opens in a new tab)Apache-2.0source file (opens in a new tab)
Open source · free files

mjbots quad

Quadruped

A quadruped walking robot with its own hardware, controlling software, and simulator, released as open-source source and design files.

Project information

Buildability
38/100Incomplete documentation
Estimated cost
Not stated
Level
Advanced
Parts
Not listed
Licenses
Apache-2.0 (opens in a new tab), hardware and software
Commercial use
Allowed

This repository contains executable files that Robotheca doesn't check. Only run them if you trust the creator.

Which files (2 files marked executable, 6 scripts)
Download the files, free (.zip at the pinned commit)Fork on GitHub (opens in a new tab)

Suggested by Robotheca, created by @mjbots (opens in a new tab), from github.com/mjbots/quad (opens in a new tab), pinned to commit 8ce3bc4 (opens in a new tab). You buy the parts yourself; Robotheca doesn't sell robots.

What to buy

This repository has no parts list Robotheca can read yet.

Why it scores 38

It measures the published files, not the robot · How we score

38/100

Incomplete documentation

How complete the published files are for rebuilding this robot, measured by Robotheca at commit 8ce3bc4. It isn't a rating of the robot. Counted out of 80 points and scaled to 100: the parts that don't apply to this robot are left out.

  1. 13D and CAD files48 printable parts (STL, 3MF).Add the CAD source (STEP, or the CAD program's own files) so people can change the design.10/20
  2. –Robot descriptionNo URDF. Not counted: the score is made of the parts that apply.Optional: add a URDF, and the robot can be seen in 3D and tried in the browser.Not counted
  3. 2Parts listNo parts list in the repository or linked.Most points to gain: Link to your parts list, or add it to the repository (a CSV or a Markdown table) with quantities, prices and where to buy each part.0/20
  4. 3SoftwareCode in this repository, instructions to install or run it.Say which software framework it uses (ROS 2, LeRobot, Arduino…).10/15
  5. 4DocumentationREADME of 1,339 characters with 0 pictures; 0 build steps.Write a README of at least 1,500 characters: what the robot does and how to build it. Split the build into at least 3 steps. Show the robot and its assembly in pictures in the README.0/15
  6. –SimulationNo simulation files. Not counted: the score is made of the parts that apply.Optional: add a simulation model (MuJoCo, Gazebo, Webots or Isaac).Not counted
  7. 5LicensesHardware: Apache-2.0; software: Apache-2.0.10/10

Build it

The guide appears here as you scroll.

Guide by @mjbots (README.md), under Apache-2.0.

More guides

Wiring and electronics

Notes written by Robotheca from the project's documents, not by its creator

Main parts: Robotheca's summary

  • Leg actuators are qdd100 servos, three per leg, with belt-driven upper legs.
  • A Raspberry Pi style computer runs the control software and wifi access point.
  • A 4Ah ONE+ battery pack powers the robot.
  • A power switch with an LED on one side controls power.

Connections: Robotheca's summary

  • The servos are connected to the onboard computer over a serial bus, as the documents imply through per-leg servo addressing.
  • The battery connects through the power switch to supply the robot.

What it can do: Robotheca's summary

Written by Robotheca from the project's documents, not by its creator
  • Walks and stands as a quadruped robot with four legs, selectable motion modes including a Stop mode.
  • Driven by a gamepad (d-pad mode cycling, analog sticks for translation and yaw) or by mouse and WASDQE keyboard keys in a web interface.
  • Supports an emote mode where analog sticks set body attitude while stopped.
  • Hosts its own wifi access point and a web control application served on port 4778.
  • Legs can be re-zeroed with a calibration script (zero_leg.py) after reassembly or belt slip.

Software

Framework
Not stated
Languages
C, C++, Python, Shell, JavaScript
License
Apache-2.0

Robotheca doesn't review code. Read it before running it.

How to run it: Robotheca's summary

Written by Robotheca from the project's documents, not by its creator.

  1. 1Build the deployment archive with the bazel build targeting //mech:quad_deploy.tar for the Pi architecture.
  2. 2Copy quad_deploy.tar to the robot's home directory over ssh/rsync.
  3. 3Stop the running software, extract the archive into /home/pi, and sync.
  4. 4In the mech directory, run ./start-robot.sh to start the robot software.

Software that runs on this robot

No software from Robotheca's catalogue found in this robot's files yet. Links come from its robot.yaml, its dependency files read as text, or Robotheca's editors.

The code

Free files

Browse all files

Every file of the project, at commit 8ce3bc4.

Community

Questions and improvements go to the creator's repository.

Add a badge to your README

For the creator: two badges that link back here. The second always shows this page's current label and score.

Listed on RobothecaRobotheca buildability

Markdown (one click selects it)

[![Listed on Robotheca](https://robotheca.org/robots/mjbots-quad/badge.svg)](https://robotheca.org/robots/mjbots-quad)
[![Robotheca buildability](https://robotheca.org/robots/mjbots-quad/score.svg)](https://robotheca.org/robots/mjbots-quad)

Other quadrupeds

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    Quadruped · Intermediate

    Score
    Buildability 94 out of 100
    Cost
    $2,230.61≈ €1,987
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    Sesame Robot

    Quadruped · Beginner

    Score
    Buildability 88 out of 100
    Cost
    $50–$60≈ up to €53

  • Open source · free files

    Zuko

    Quadruped · Advanced

    Score
    Buildability 84 out of 100
    Cost
    Not stated

  • Open source · free files

    Quadruped Bai Servo v1

    Quadruped · Intermediate

    Score
    Buildability 81 out of 100
    Cost
    Not stated

≈ € values are approximate, converted at the ECB euro reference rate of 5 Nov 2026. The creator's original price always comes first.