Petoi Programmable Quadruped Robot System Overview

Petoi programmable quadruped robots are mini but powerful and affordable robots that can play tricks like real animals.

robot cat Nybble

They move with four legs rather than wheels. Legged motion gives them more freedom to navigate unstructured terrains, and expresses the joy of life whenever they move. Such dynamic maneuverability was only seen on a few luxury robots from the best labs or tycoon companies previously, such as Boston Dynamics Spot or Sony Aibo.


robot dog Bittle walking and self-righting


  • Petoi robots are brought to life by assembling its puzzle-like frames and configured & remote controlled via Petoi mobile app

  • They are programmable via C/C++/Python.

  • They have dynamic agile maneuverability and gaits that are performed like real four-legged animals.

  • With our customized Arduino board coordinating all instinctive and sophisticated movements, you can clip on various sensors to bring in sensing and perception.

  • Inject artificial intelligence capabilities by mounting a Raspberry Pi or other AI chips through wired/wireless connections.

  • Built on the popular open source robotic pet framework OpenCat , Petoi robots acts as an open platform for any robotic dream. 

  • Petoi robot pets makes a perfect tool for learning, teaching, researching, or a surprising gift to impress your family and friends. 


Ball tracking with an intelligent camera mounted on the mouth of Bittle

System Overview

To solve the varies challenges and strike a fine balance of cutting-edge technology and cost-effectiveness to fit in a compact form factor that can be commercialized, affordable, and mass-producible, we've designed and engineered a robotic system of five major components: body frame, actuator, electronics, power source, and the software to coordinate all the hardware to perform varied tasks. 

Body frame

Our robots are designed with interlocking frame as a puzzle with a few screws involved. Most body parts are symmetric for simplicity and aesthetics. 

Robot Cat Nybble Frames

robot cat Nybble frames


Assemble the frames of robot dog Bittle
Assemble the frames of robot dog Bittle


Build a robot dog on your own

Build a robot dog on your own!


A great actuator is the core of any quadruped walking robot.  As the pioneer in mini quadruped robots, we found no off-the-shelf servos when we started to produce our products. So we first ODMed a precise servo with perfectly tuned PID to meet the challenges of powerful, fast yet stable quadruped walking for Nybble.  For the second product Bittle, working with the factory from the very first day with many iterations, we designed a brand new servo P1S that's slim and fast with a controllable angle of 270 degrees.

P1S servo

We use nine metal or plastic servos to actuate Bittle. Eight of them are for walking joints, and one is for head panning. We will also include one spare servo for replacement, as brushed motors are consumable after a certain period of wearing. You may order the "Bittle Servo Set" perk if you expect to use Bittle intensively for teaching or researching.



Petoi robots are driven by NyBoard V1, a customized Arduino board with rich peripherals. We fully utilized the chip of a regular Arduino Uno to coordinate sophisticated motions. The board can drive at least 12 PWM servos, and an IMU (Inertial Measurement Unit) is used for balancing. It stores "muscle memory" and detects body status (orientation and acceleration) for balancing. We provide an infrared remote to trigger basic movements. The board also listens to string commands from the serial port, such as "walk", "sit", or more detailed instructions for individual joints. 


Petoi Robots Electronics

NyBoard V1 has been driving thousands of Petoi robot dogs and cats all over the world. We continue to provide a 2x5 socket on NyBoard V1 for mounting Raspberry Pi. It powers the Pi and communicates with it through the serial or I2C network. The Pi gives Petoi robots the ability to analyze more sensory data, get connected to the Internet, and make decisions by itself.   You may need to tilt the Pi and 3D print some supporting structures depending on which Petoi robot you use. 


Pi camera on Bittle

 Raspberry Pi 3 A+ and Pi camera on Bittle

Thanks to the Arduino and Raspberry Pi community, you can find many customization ideas for Bittle. There are four Seeed Grove sockets on NyBoard V1 for extensible modules. To make installation easier, we designed Bittle's head as a clip to bite on those modules. That explains why we created a dog out of OpenCat this time. There's also a screw hole inside Bittle's head for fixing additional modules. 

NyBoard V1


We developed a Bluetooth dongle for wirelessly uploading codes and controlling Petoi robots from PC or smartphone Apps. We also developed a WiFi dongle for wirelessly communication. You can play with Petoi robots without messing around with cables. Wireless is also essential when you are studying balancing related motion planning. You can even utilize the computational power of a remote "brain" without being constrained by Petoi robot's min size and cargo capacity. 

Bluetooth and WiFi dongles

Furthermore, we've developed an ESP32 development board with native Bluetooth and WiFi connectivity. We have made a functional beta version called the "BiBoard V0" for developers. It has a considerable performance boost, and you are welcome to join our exploration.

BiBoard V0

Both boards work with Nybble and Bittle.  You only need to plug the servos to the right ports following the joint pins' assignment. 


All Petoi robots are driven by our OpenCat code. It has 3K lines of Arduino codes excluding 3rd party libraries. It defines the minimal data structure and algorithms for performing quadruped motion. It works for Nybble, Bittle, and the generic OpenCat robots in the future. All you need is to download the default demo code from GitHub, change the model definition at the beginning of the code, then upload it to the robot.  

We also provide example commander and parser in Python so that you can send instructions from other devices. The code is already running on thousands of small quadruped robots, including many variants of OpenCat.  

Petoi Robots Software


You can program Petoi robots at different levels in various coding environments, such as Scratch-like drag & drop coding environment Petoi Coding Blocks, C++ in Arduino IDE and Python in the terminal.  We also provide free robotics curriculums in Petoi Coding Blocks and C++.

Petoi Coding Blocks




 Bittle climbing up a step under realtime instructions sent through Bluetooth

Power Source

We designed a Li-ion battery pack with a built-in charging and protection circuit. It can slide into the track underneath Bittle and Nybble and tune its center of mass. It can power Petoi robots for at least one hour of continuous walking. It also has an RGB LED to indicate the battery's status.