Petoi Bittle – a Palm-Sized Robot Dog for STEM and Fun


Petoi Bittle is a tiny but powerful robot that can play tricks like real animals. We fine-tuned every bit to fit agile maneuverability into a palm-sized robot pet. You can bring Bittle to life by assembling its puzzle-like frame and downloading our demo codes on GitHub. You can also teach it new skills to win prizes in our community challenges. Bittle makes a perfect tool for learning, teaching, researching, or a surprising gift to impress your family and friends.

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  • Open source – Bittle is an open platform powered by OpenCat to fuse multiple makers’ gadgets into one organic system.
  • Arduino-powered extensibility – with our customized Arduino board coordinating all instinctive and sophisticated movements, you can clip on various sensors to bring in perception.
  • Artificial intelligence – one could also inject artificial intelligence capabilities by mounting a Raspberry Pi or other AI chips through wired/wireless connections.

* Use the optional intelligent camera module mounted on Bittle’s mouth to recognize and follow the object

* Self-righting after falling from a slope (triggered by an infrared remote)

* Climbing up a step under realtime instructions sent through Bluetooth

What’s included

  • Bittle
  • Bittle battery
  • Bittle shell
  • NyBoard V1
  • Bluetooth  dongle
  • Wifi dongle
  • 10x P1S servos

Bittle is a palm-sized robot that moves with four legs rather than wheels. Legged motion gives it more freedom to navigate unstructured terrains, and expresses the joy of life whenever it moves. 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. We came up with a grassroots solution to simplify the system to make it affordable and mass-producible.

Bittle consists of five major components: body frame, actuator, electronics, battery, and the software to coordinate all the hardware to perform varied tasks.

Body Frame

We designed Bittle’s interlocking frame as a 3D puzzle with very few screws involved. Most body parts are symmetric for simplicity and aesthetics.

It’s a pleasure to assemble and disassemble Bittle for teaching or maintenance. On average, it takes about one hour to put together the body from scratch.

Build a Robot Dog on Your own!

Each piece has gone through tens of iterations with 3D printing. We then use high strength injection-molded plastic to provide the best protection from collision and dust (it’s NOT waterproof!). In the stress tests, the assembled robot can take an adult’s stepping without breaking any components (do NOT try this at home!).

We also designed Bittle to be soft. Besides the elasticity of the material, the spring-loaded upper legs flatten the shock on joint servos to protect their gears. Bittle usually survives regular collisions. In the extreme cases, it will disintegrate at the designated “weak link in the chain”, which is easy and cheap to reinstall or replace.

We designed the frame to be compatible with most 9g servos. You could order the “Bittle Shell” perk alone to compile your spare servos into a beautiful action figure!


We visited several servo manufacturers and iterated many times to find the optimized parameters. It will be model P1S, a slim, fast servo with a controllable angle of 270 degrees.

We use nine P1S 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.


Bittle is 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.

* NyBoard V1

NyBoard V1 is a revision of NyBoard V0 that has been driving 2000 Nybbles all over the world. We continue to provide a 2×5 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 Bittle the ability to analyze more sensory data, get connected to the Internet, and make decisions by itself. Due to Bittle’s small size, it best fits Pi Zero and Pi 3A+. For larger Pi models, you will need to tilt the Pi and 3D print some supporting structures.

* Raspberry Pi 3 A+ and Pi camera on Bittle.  Note that the Pi and camera are not included in the standard product package.

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.

* Extensible Modules (not included in the standard kit)

We developed a Bluetooth dongle for wirelessly uploading codes and controlling Bittle from PC or smartphone Apps. We also developed a WiFi dongle for wirelessly communicating with Bittle. You can play with Bittle 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 Bittle’s size and cargo capacity. The dongles are compatible with our previous Nybble model.


* Bluetooth and WiFi Dongles


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

* Li-ion battery with onboard charging and protection circuit

With the slide-in installation mechanism and an anti-reverse plug, it’s not too hard to switch batteries. You may order extra batteries for uninterrupted researching or playing. With some reconfiguration, it can also power our previous Nybble models.

Powered by OpenCat, the open-source Arduino and Raspberry Pi-based robotic pet framework developed by Petoi

OpenCat has 3K Lines of Arduino codes excluding 3rd party libraries. It defines the minimal data structure and algorithms for performing quadruped motion. 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.

Supporting Software

You can program Bittle at different levels in various coding environments, such as C in Arduino IDE and Python in the terminal. We are collaborating with TinkerGen, a STEM education company that kindly developed Codecraft (a graphical coding environment) for Bittle. They will also provide a free curriculum for you to learn programming in Codecraft and create a wide array of educational and fun projects with it!

You can code in Arduino IDE, Python, Codecraft, and many other environments

* An iOS/Android App (Code & Robots) developed by one of our fans

To make our community more productive, educational, and rewarding, we’ve launched an online challenge for all OpenCat users. You can find our proposed rules in this forum post and give suggestions before it officially starts. In short, we will define several tasks that can be measured quantitatively, e.g., programing Bittle to get onto the highest step. You have to both demo your solution and teach others to validate your entry. On the first day of each month, we will announce the world’s record-breaker and gift a free Bittle or Nybble to the winner!

Bittle is 20cm x 11cm x 11cm in dimension. It weighs less than 280g but can carry up to 450g cargo under its belly. With proper programming and calibration, It can run faster than two body lengths per second. Bittle can remember tens of instinctive motion patterns and can perform more fancy tricks with real-time instructions.

P1S servo uses a coreless motor, alloy gears, ball bearing, and plastic case. It’s 8.4V compatible, high speed, and has a controllable range of 270 degrees.

NyBoard V1 has an Atmega328P with 16MHz CPU, 2K SRAM, and 32K flash. We also added an 8K I2C EEPROM, an IMU, a servo driver for 12 PWM servos, an infrared receiver, and a buzzer. It has a 2×5 socked to mount on a Raspberry Pi.

The Bluetooth dongle is compatible with Windows, macOS, and Android. It can also work on IOS with some auxiliary software. It can be used for uploading Arduino sketch or communicating with the NyBoard. The WiFi module can host a simple WebUI and communicate with the NyBoard.

The optional intelligent camera module is our ODMed product. It integrates multiple vision recognition algorithms running on its ESP32 dual-core processor. It can return recognized human body, objects, and symbols through serial/I2C/WiFi at a rate of 25fps or 50fps. It can even stream video through WiFi. We will also include a deck of symbol cards. You can refer to this link for more information.

Note: Bittle is not a toy for small kids. We recommend parental guidance to appreciate its rich content and avoid damage or injury.

Additional information

Weight 1.5 lbs
Dimensions 10.63 × 7.5 × 2.76 in


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Product Manuals

If applicable, the Product Documentation, Reference Materials, CAD design(s),.STEP file(s) and/or other drawing files, Manuals, and Tutorials will be available for download upon purchase. The order confirmation email will include a downloadable link to the product file(s), which can also be downloaded from the My Account section if needed.

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Return Policy

EXCHANGE POLICY: Oz Robotics wants you to be happy with your new purchase. However, we abide by the exchange policy of our suppliers because we do not manufacture these products; our suppliers do. Please read the product exchange policy defined by each supplier for their own listed product(s), which can be found under the Shipping tab on each product page. Once you have used the product, our supplier(s) and we have the right not to issue a refund. Still, they will offer an exchange for the wrongly purchased items or products with serious and irreversible defects or technical problems (s). If wrongly purchased products or any other similar issues, the buyer will pay the shipping fee. If the product you purchased is defective, please email us at with some photos or a video of the defective parts to evaluate before you send it. Click HERE for more on Refund and Replacement Policy

REFUNDS/RETURNS: Oz Robotics accepts returns on a minimal basis unless there is a manufacturing defect. For any electronic items, returns are only accepted on devices with serious and irreversible problems; meanwhile, the customer must apply for the returns within 7 days from the delivery date. Before a refund acceptance, please include images or a video and any other material proof of the defect. However, we abide by the exchange policy of our suppliers because we do not manufacture these products; our suppliers do.

Other than our supplier’s default policy, once a return is agreed upon, then you can ship your defective item to the provided return address that you should receive from us first. Please ship the order in original packaging with all the accessories and additional parts. If the Required Parts are not sent back, they will be billed for or expected to be shipped at a later stage. And only once all items have arrived as a full system can we check the returned product for testing. Include in your package a signed letter stating the reason for your return and the original receipt as well as any mentioned proof of defect, images, or a video, etc. This will help us to speed up the process on your behalf.

The purchaser (customer/buyer) is responsible for all shipping costs when returning an item. However, upon receiving the returned order, we will assess the product. If it is determined that there is, in fact, a manufacturing defect, then we will refund the shipping costs as well as repair or replace or refund the full amount to the purchaser if the product is not fixable.

If you wish to return an unused product, please do so within 7 days from the ship date for a refund on the purchase price, minus shipping, handling. Refunds will be credited to the original credit card use for payment in 24-48 HOURS after receiving the product back. We will charge 50% restocking fee.

Once your return is received and inspected, and if agreed for a refund, refunds will be credited to the original credit card used for payment in 24-48 hours. Please note that we will charge a 50% restocking fee if you want to return a product without any defect.

Once your refund is processed, then PayPal will return the money to the card that was used. It may take at least 5 business days (depending on the bank and credit company) before your refund is officially posted in your bank account and statements. Contact Us if you still have not received your refund after 5 business days.

Do not return your product to our New York office. For any exchange or refunds, please email us first at for us to provide you with the steps that need to be followed. Any product you return must be in the same condition you received and returned in the original packaging without being used. Please keep the original receipt. More on Refund and Replacement Policy.

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