Build Your Own Robot 'Dog Bittle' by Learning Robotics & Programming

September 8, 2022

Bittle is a palm-sized robotic dog from Petoi. It is a fully programmable robot running on an open source robotic framework called OpenCat. Bittle was "born and raised" through crowdfunding campaigns on Kickstarter and Indiegogo in 2020. By putting together its components, and programming it, you can get a good taste of what programming and robotics entail. Rongzhong Li, founder of Petoi, has developed Bittle and its supporting ecosystem to bring STEM and robotics education to everyone at an affordable price.


OpenCat - Quadruped Robotic Framework

Petoi has developed its project very systematically and with a long-term vision. The deep thinking behind Petoi's efforts is to create a community of robotics and programming enthusiasts from around the world. So, it started by creating and publishing OpenCat, an open source programming framework for robotics. Using it, anyone can turn their prototype robots fitted with Arduino micro-controllers or Raspberry Pi microprocessors into highly programmable and extensible robotic pets.

opencat diagram

Rongzhong Li, the founder of Petoi, says that Boston Dynamics robotic dog videos inspired him. He wanted to bring robotics closer to ordinary people by making it cost-friendly and easy-to-execute. So, in 2016, the first step was to build OpenCat framework and publish it on Github. Making this framework open-source made it easy for programming and orbotics enthusiasts to contribute to and improve the codebase. 100s of DIY robotic pets were built, as you can see in the following playlist.

However, the barrier to entry was still high since one needed to design and fabricate their own components. This led to Nybble and Bittle projects, to create LEGO-like commercial robotics kits that anyone could put together and play with.

Bittle and Nybble

Bittle and Nybble robot pets from Petoi OpenCat

Bittle the pet dog robot, is a successor to the pet cat robot from Petoi called Nybble. Being next generation, Bittle has improved features compared to Nybble. Bittle is lighter than Nybble, its assemble times are faster, has a Li-ion battery pack included, and a longer battery life. While Nybble's body is made of wood, Bittle parts are fabricated in plastic material making it more durable. Bittle also allows for easier mounting of additional components like sensors and controllers, to give it extra features, like AI vision. Nybble launched in 2018 and Bittle in 2020. They were both crowdfunded initially, and are now available for purchase on popular online stores.

bittle kit

While putting together your robotic pet is a fun activity, Petoi also ships Bittle and Nybble in assembled, ready-to-use form for additional price.

Assembling Bittle

Bittle's standard package ships as disassembled parts. You must follow the instructions to put together these pieces like a 3D puzzle or LEGO. It usually takes 40 to 90 minutes to assemble Bittle. The "muscles" and "joints" of this pet robotic dog are its 9 P1S servos which are high-quality and powerful. A modified Arduino board called Nyboard V1 is the "brain". It ships with a 7.4V 1000mAh Li-ion battery pack that fully charges in 2 hours and lasts for 1 hour of action.

Bittle Calibration

An important part of assembling Bittle is to arrange all its joints (head and legs) in a "zero" or "ground" position. This is the "calibration" check. If you don't do this step properly, all of Bittle's motions will be awkward.

To calibrate Bittle, you need to download the iOS, Android or Desktop app. Connect the bluetooth dongle to the Nyboard, so that the apps can "talk" to it wirelessly. And then follow the steps given in the calibration module. These apps also have a control panel to control Bittle's motion when it is ready to play. Bittle also ships with an infrared remote controller to make it perform some standard actions and tricks.

bittle calibration2

Default Actions

Once you are done assembling and calibrating your pet robotic dog, it is time to play with it! The fastest way to interact with Bittle is using the IR remote controller. The remote has featured motions like basic directional movements (forward/left/right/backward). And some standard pre-programmed actions like walk, trot, crawl, step and sit. There are also some fun tricks like greeting, push up, look up and pee. If anything is not working correct, you should hit the "Rest" action, to quickly reset Bittle's servos and posture.

bittle default actions

Programming Your Pet Dog Robot

You can program Bittle to perform new skills and activities. Thanks to its open-source design, it is compatible with many programming languages and IDEs, including C in Arduino IDE, Python in terminal, and Codecraft.

codecraft, python, arduino

For kids and beginners, Petoi has collaborated with Tinkergen to produce a Scratch-like programming environment called Codecraft. You can drag and drop various blocks of code to make Bittle perform a series of preplanned actions and sounds. There is also a free course for teaching you how to program Bittle using Codecraft.

For intermediate and advanced programmers, there are many community created projects and tutorials. You can find out if there is a guide or a library for working with Bittle in your favorite programming language. Even standard robotics platforms like ROS will work with Bittle. That's the power of creating an open-source, community-driven platform.

Extensible Modules

extensible modules

Apart from the standard electronic components that ship with Bittle, you can also add other sensors and controllers. This will add new capabilities to your pet dog robot. It includes light sensors, sound sensors, gesture sensors, OLED displays, touch sensors, and motion sensors. The head of Bittle is designed to easily clip these extensible modules. You can also connect Raspberry Pi to Bittle, either onboard its body or wirelessly. With these additional hardware, you can bring the power of Artificial Intelligence (AI) to your pet roboto and make it behave in more intelligent ways.

Creativity is your limit!

Once you have mastered the basics of working with Bittle, you can try out fun creative projects. With Bittle, OpenCat, Codecraft, extensible modules and other community powered resources, you can share and create amazing projects and ideas for playing with your pet robot dog. Here's a football match between two Bittles presented by the founder Rongzhong Li and his team at Petoi.


Petoi has built a wonderful ecosystem to lower the barrier of entry to robotics. By creating a commercial, affordable, and lightweight product like Bittle, while also having open-source extensibility, it brings a powerful set of tools in robotics and programming to your doorstep. Thanks to the financial and creative contributions from worldwide community, there is a rich repository of projects, guides, and discussion forums to help you get the most out of Bittle. Tell us in the comments what you think of Bittle the pet robot dog, when will you get one, and what will you do with it?

bittle featured image

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