About this project

OpenCat is an open-source framework from Petoi for building and programming quadruped robots, developed originally by Dr. Rongzhong Li starting in 2016 and inspired by Boston Dynamics' Spot. It is the codebase behind the Bittle robot dog and Nybble robot cat mini kits, and it handles the low-level work of gait coordination, servo control and IMU integration so users can build on top of it. Scope and hardware This repository targets the legacy NyBoard platform, a customized Arduino board based on the ATmega328P that coordinates up to 12 servos for walking, running, jumping and backflipping. The README notes that current-generation hardware (Bittle X, Nybble Q, BiBoard/ESP32) is covered by the separate OpenCatESP32 repository, and that the original Bittle and Nybble robots are discontinued but still supported here. Extension options mentioned include a sensor pack, an intelligent camera module, and Raspberry Pi, Nvidia Jetson Nano or other AI co-processors connected wired or wirelessly. Capabilities described The framework is presented as multi-language (C/C++, Python, block-based coding), open hardware and software without vendor lock-in, and native to Arduino and Raspberry Pi tooling. It supports sensor integration such as cameras, touch, IMUs and ultrasonic sensors, sim-to-real experimentation with reinforcement learning models, and ROS-compatible SLAM, navigation and perception pipelines documented by the community. Setup workflow The README walks through a configuration flow in the Arduino IDE: clone the repo, open OpenCat.ino and select the robot (BITTLE or NYBBLE) and board revision via defines, comment out MAIN_SKETCH to enter configuration mode, optionally enable AUTO_INIT for automatic IMU calibration, upload, open the Serial Monitor at 115200 baud with no line ending, reset joint offsets, calibrate the IMU by placing the robot flat, then switch back to MAIN_SKETCH and re-upload. Joint calibration can be done by booting with one side up or through the Serial Monitor, and an optional Bluetooth dongle enables calibration through the Petoi mobile app on iOS and Android. Control afterwards is possible via infrared remote, the app, Python or the Serial Monitor. Community and ecosystem The README lists community projects including autonomous movement and object detection, Raspberry Pi robotics, AI and computer vision applications, NVIDIA Isaac simulations and reinforcement learning, visual and LiDAR-based SLAM with ROS, imitation learning with Tiny ML models, IoT robot fleet management with AWS, and 3D-printed accessories and custom builds. It also points to education resources for K-12, community colleges, university labs and maker spaces, robotics competitions, and a research spotlight page. Discussion happens on r/OpenCat for firmware and framework work and r/Petoi for hardware and general topics, plus a Facebook group. Project context The README states 30,000+ robots shipped across all channels, presence in 60+ countries, $1M+ raised across two prior crowdfunding campaigns, and 20+ academic papers citing the platform. It also announces Quaddle, a forthcoming mini robot dog on the same OpenCat lineage, with source code not yet public and planned for release before delivery. The legacy OpenCat-Old repository is archived and no longer maintained.