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A HOMEMADE ROBOT DOG NAMED AFTER SPOT SPELLED BACKWARDS

A 12-DOF robot dog with custom quasi-direct-drive actuators and 3D printed planetary gearboxes, built in four months for 3,300 dollars.

by Aaed Musa

FULL CAD BOM FIRMWARE DOCS

Robotics

Built withArduinoTeensy3D printing

difficulty
●●●●●
time
four months
license
license not specified
repo
repo ACTIVE298 stars

WHAT YOU’LL NEED

Videos
1
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COMPAREE VERDICT

TOPS is a serious robotics build that assumes you can commission ODrive motor controllers, tune the gains, and read a schematic with twelve motor drives on a CAN bus. Aaed Musa designed every actuator himself: a 90KV brushless motor, a 3D printed 9:1 planetary gearbox, and an ODrive S1 FOC controller at each of twelve joints. A Teensy 4.1 runs the leg kinematics and talks to all twelve drives over CAN bus. The frame is carbon fiber, the feet are silicone, and the whole thing weighs 13.43 kg. Total cost is about 3,300 dollars, with the twelve ODrive S1 boards being the single largest expense. The repository has the CAD, the BOM, the code, and a schematic, but no step-by-step assembly or commissioning guide. The most likely place this goes wrong is ODrive tuning: if you have never done FOC motor setup before, expect it to take real time. The YouTube video shows the finished robot moving and dancing. The author's own build took four months. If you have built a multi-actuator robot before and want to go further, this will teach you a lot. If this is your first brushless motor controller, start with something smaller.

GOOD TO KNOW

  • —CAD assembly ZIP file and BOM spreadsheet are in the repository.
  • —Arduino code for Teensy 4.1 is present, plus custom libraries for ODrive CAN communication.
  • —Full robot schematic PNG and a QIK derivations PDF (the leg kinematics math) are included.
  • —No build instructions, assembly guide, or wiring walkthrough — you are reading code and a schematic.
  • —No licence file in the repository.
  • —Last commit October 2023; project appears finished rather than abandoned.

Parts to buy

12 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • 12x Eaglepower 8308 90KV brushless motorsFind
  • 12x ODrive S1 controllersFind
  • Teensy 4.1Find
  • 6S 5200mAh LiPo batteryFind
  • Carbon fiber tubesFind
  • BearingsFind
  • Encoder magnetsFind
  • Timing beltsFind
  • RC transmitter and receiverFind
  • 30A silicone mix for the feetFind
  • PLA filamentFind
  • Screws and insertsFind

Can I build this?

PrintAll structural parts, motor mounts, gearbox housings and leg segments: 4.53 kg of 3D-printed parts in total. The BOM lists PLA filament.
Buy12x Eaglepower 8308 90KV brushless motors, 12x ODrive S1 controllers, Teensy 4.1, 6S 5200mAh LiPo battery, carbon fiber tubes, bearings, encoder magnets, timing belts, RC transmitter and receiver, 30A silicone mix for the feet, PLA filament, screws and inserts. Full list in the BOM spreadsheet.
Tools3D printer with enough build volume for the leg segments, soldering iron, CAN bus wiring tools, ODrive configuration software, multimeter, power supply for bench testing
SkillsFOC motor controller setup, CAN bus wiring, inverse kinematics tuning, Arduino/Teensy programming, reading electrical schematics — this is an advanced robotics build
TimeThe author's build took four months. Faster if you have commissioned ODrive boards before, but still weeks, not days.
Cost$3,300 total according to the README (the BOM adds up to about $3,330). The twelve ODrive S1 controllers at $149 each are roughly $1,790 of that.
Safety6S lithium polymer battery (22.2V, high discharge current) — charge in a fireproof bag, never leave unattended, store at storage voltage. Rotating gearboxes and motor shafts during testing.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

I Built a Robot Dog and Made it Dance15:00

Aaed Musa's build video (6 Oct 2023), linked from the README.

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read the QIK derivation PDF and schematic PNG to understand the kinematics and wiring before ordering parts (The code assumes you understand the math; the PDF explains it)
  2. 2.Order one ODrive S1 and one motor first, get that working on the bench before committing to twelve (Tuning FOC parameters is the hardest part of this build; do not buy everything until you have done it once)
  3. 3.Print one leg segment and gearbox housing to verify your printer can handle the part sizes and tolerances (The gearbox fit is critical and the leg parts are large)
  4. 4.Follow the BOM spreadsheet for the full parts list (Motor and controller models are specified; bearing sizes and fasteners are listed)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • No assembly instructions means you are interpreting the CAD yourself; expect to open Fusion 360 or similar and rotate parts to see how they mate.
  • CAN bus wiring for twelve nodes is not trivial — termination resistors, twisted pair, and node addressing all matter.
  • The printed planetary gearboxes require tight tolerances; if your printer is not well-tuned, gears will bind or have excessive backlash.
  • The code includes custom ODrive CAN libraries that may need updating if you use a newer ODrive firmware version.
  • Inverse kinematics tuning takes time — the robot will not walk smoothly on the first power-up, and there are no tuning guides in the repo.

What is the licence?

There is no licence file in the repository, so technically all rights are reserved. Reach out to Aaed Musa if you plan to commercialise derivatives.

Can I use different motor controllers?

The code is written for ODrive over CAN bus. Porting to another controller means rewriting the communication layer and possibly the control loop.

What 3D printer do I need?

The 3D-printed parts weigh 4.53 kg in total and the leg parts are large, so check the CAD for exact dimensions against your printer's build volume. The BOM lists PLA filament.

Is this easier than openDog V3?

Not really. James Bruton's openDog V3 also uses ODrive-controlled brushless motors (with printed cycloidal drives), so both builds need motor-controller setup and tuning. TOPS adds its own 3D-printed planetary gearboxes and twelve ODrive S1 controllers.

Community builds

No community builds yet — be the first, we feature the best ones.

Discussion1

FROM THE COMPAREE TEAM

For someone who has never tuned a FOC controller, what would you build first to learn on?

CompareeTEAM6d ago

Practical notes from our verification: the YouTube video linked in the README is the October 2023 upload showing the finished robot, there is no assembly guide so you are working from the schematic and CAD alone, and the BOM spreadsheet lists component names, prices and quantities but no supplier links, so expect to source parts yourself. The single biggest cost is the twelve ODrive S1 motor controllers ($149 each in the BOM), and the single biggest time sink will be learning to tune them if you have not done FOC setup before.

Aaed Musa

Aaed Musa is a robotics builder who designed TOPS after earlier attempts at quadruped robots that did not achieve a natural gait. The project was inspired by James Bruton's openDog V3 and took four months to complete.

GitHub Web

Star the project on GitHub

DISCLAIMER

  • Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
  • Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
  • Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
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