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QuadrupedPetoi2020US

Bittle / Bittle X

Palm-sized servo-driven robot dog kit for STEM education running the open-source OpenCat framework; Bittle X is the current version.

activeKitL1 Compiledbuildable

Difficulty index

7.5/13
7.5
Index breakdown
Classquadruped+3.5
Costunknown · midpoint+1.5
DOFunknown · midpoint+1.5
Partsunknown · midpoint+1
How the index works

Specimen photographs

2 items
  • Petoi Robot Dog Bittle: Open Source Robot KitPetoiCamp · official video, embedded · source
  • Introduction of Petoi Bittle X | Smart Programmable Robot Dog For Everyone | Petoi CampPetoiCamp · official video, embedded · source

Spec card

5/13 known
Mass
0.29 kg
Runtime
60 min
Actuators
PWM servos
Compute
NyBoard V1 (customised Arduino Uno) on original Bittle
Sensors
IMU

Not in the registry: degrees of freedom, height, payload, speed, battery, price, bom total, part count. 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
  • +Reading and flashing open firmware
  • +Testing in simulation (URDF/MJCF) before touching hardware

Openness

45/100
  • not publicCAD
  • not publicBOM
  • publicFirmware
  • publicSim model
  • publicSoftware
  • not publicPolicies

Score 45/100 computed from what is public: CAD 25, BOM 20, sim 20, firmware 15, software 10, policies 10. Software license: MIT.

Repos & models

URDF ↗
SiteDocsBuy

Build it

Sold as a kit.

No ORP build package yet.

That means no BOM with prices, no fabrication list and no step graph in the registry. Build from the upstream material, or write the package: a robot.toml plus BOM and steps.

Package spec on buildhumanoids.dev

Upstream

Simulate

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

Open on humanoidrobots.training ↗

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.

NoteOnly the firmware/software (OpenCat) is open: GitHub reports MIT while Petoi's site says GPL3+. Injection-molded frame CAD not found published, so cad/bom=false. Runtime ~1 h walking per New Atlas. OpenCat repo was renamed from PetoiCamp/OpenCat. A simplified URDF (bittle_simple.urdf/.xml) is in Resources/SimulationModels.

Sources

  1. [1]New Atlas: Bittle Kickstarterchecked 2026-09-24
  2. [2]OpenCat repochecked 2026-09-24
  3. [3]BBC Science Focus reviewchecked 2026-09-24
  4. [4]Petoi Bittle X product pagechecked 2026-09-24