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QuadrupedJames Bruton (XRobots)2021GB

openDog V3

Large 3D-printed hobby quadruped using brushless motors with ODrive controllers and printed cycloidal gearboxes; CAD, code and BOM are published.

orphanedDIYL1 Compiledbuildable

Difficulty index

8.5/13
8.5
Index breakdown
Classquadruped+3.5
Costunknown · midpoint+1.5
DOFunknown · midpoint+1.5
Parts1886 parts+2
How the index works

Specimen photographs

3 items
  • Robot Dog V3 - 3D Printed & Open Source #1James Bruton · official video, embedded · source
  • openDog V3: How I made it WalkJames Bruton · official video, embedded · source
  • 3D Printed Robot Dog Climbs Over ObstaclesJames Bruton · official video, embedded · source

Spec card

2/13 known
Part count
1886
Actuators
Brushless motors + ODrive, 3D-printed cycloidal drives, AS5047 encoders

Not in the registry: degrees of freedom, height, mass, payload, speed, runtime, battery, price, bom total, compute, sensors. Left blank rather than guessed.

What you learn building it

  • +Gait generation
  • +State estimation from an IMU
  • +Sim-to-real policy transfer
  • +High-current power and motor drivers
  • +FDM 3D printing: 92 parts
  • +Tools used: STEP-capable CAD (Fusion 360, FreeCAD, Onshape import), FDM printer, Saw for carbon fibre (with dust extraction and mask), Hacksaw or cut-off tool, Calipers, Hex keys, Pozidriv screwdriver, Soldering iron +8
  • +14 assembly steps across 7 subassemblies
  • +Flashing firmware for Teensy 4.1 (openDogV3.ino, Arduino/Teensyduino), Teensy LC (Remote.ino), ODrive v3.6 x6 (stock firmware, configured with odrivetool)

Openness

70/100
  • publicCAD
  • publicBOM
  • publicFirmware
  • not publicSim model
  • publicSoftware
  • not publicPolicies

Score 70/100 computed from what is public: CAD 25, BOM 20, sim 20, firmware 15, software 10, policies 10. Hardware license: MIT. Software license: MIT.

Repos & models

SiteDocsVideo

Build it

Has an ORP build package.
BOM total
unpriced
Lines priced
0/44
Parts
1886
Steps
14
Version
0.1.0

44 lines have no price yet, so the real total is higher.

Largest BOM lines

Largest bill of materials lines
PartQtyUnit
9225 90 KV brushless motor (HobbyKing/Turnigy Multistar 9225 90 KV or EaglePower 8308 stator / 9225 can 90 KV)12?
ODrive v3.6 BLDC driver (2 axes each)ODrive v3.66?
AMS AS5047P motor encoder board (one per axis, absolute SPI mode)AS5047P-TS_EK_AB12?
Teensy 4.1 (dog controller)Teensy 4.11?
Teensy LC (remote controller)Teensy LC1?
5 V / adjustable step-down regulator (set to 5 V for the Teensy and dog electronics)1?
MPU6050 IMU (used only by the experimental_stability sketch)MPU60501?
NRF24L01 2.4 GHz radio (one in the dog, one in the remote)NRF24L012?

Fabrication

  • FDM 3D printing92
Firmware repo
  • No written assembly instructions: the build is only shown in the YouTube playlist. The drive, leg and body steps here only restate BOM notes and code; sequence and fits must come from the videos and the STEP assembly.
  • No STL set: printable parts must be exported from the STEP files. Only the cycloidal internals and foot mould have their own files.
  • BOM.ods has no prices. The only price is a note ('$70 for 400' small bearings); the robots.ts '~$2000' figure is not in the repo. Most links are UK retailers (eBay UK, Amazon UK, CEF, Simply Bearings) or AliExpress; eBay/AliExpress listings expire.
  • Three Cool Components links (Teensy 4.1, Teensy LC, MPU6050) returned 404 on 2026-09-25. PJRC lists Teensy LC as discontinued and not recommended for new designs.
  • Links point at ODrive's 'latest' docs, which now cover the newer ODrive firmware; openDog uses ODrive v3.6 with the 0.5.x odrivetool API. Motor pole pairs, current limits other than the 20 A set in code, and ODrive config files are not published.
  • BOM inconsistencies: leg screws '18 per leg' but 56 listed; the remote code drives a 20x4 LCD but only one (16x2) LCD is listed; the remote battery is not listed; the CAD shows 2020 aluminium extrusion (stand) that is not in the BOM; knee pulleys and wiring/connectors for the high-current side are not listed.
  • The author says the BOM is 'probably complete'. The repo was last updated March 2023; robots.ts marks the project orphaned.
  • No torque values, print times or filament totals are published.

Simulate

humanoidrobots.training/xrobots/opendog

No public URDF or MJCF.

Next rung

Z-Bot (Zeroth Bot) →K-Scale Labs · humanoid · index 8.4

No buildable class sits between quadrupeds and humanoids yet, so the next rung is the easiest humanoid.

NoteOne-person YouTube project; repo last pushed Mar 2023. City omitted (not public on GitHub). BOM.ods lists parts and links but no prices.

Sources

  1. [1]openDogV3 repo (MIT, BOM)checked 2026-09-24
  2. [2]openDogV3 BOM.ods (no prices)checked 2026-09-25
  3. [3]Hackaday: openDog V3 (Dec 2021)checked 2026-09-24
  4. [4]3D Printing Industry: V3 developmentchecked 2026-09-24