Bittle X

Overview

The Petoi Bittle X is an open-source programmable quadruped robot targeted at education and hobbyist programming. Manufactured by Petoi, a US-based company, it is a palm-sized robot with 8 degrees of freedom, Arduino and Raspberry Pi compatibility, and a focus on teaching programming, kinematics, and electronics. At $400, it is one of the most affordable entry points for hands-on quadruped robotics. It is not a research-grade locomotion platform.

Key Specifications

• Degrees of freedom: 8
• Payload: minimal (sensor mounting only)
• Top speed: approximately 0.5 m/s
• Weight: approximately 0.35 kg
• Microcontroller: NyBoard (Arduino-compatible) or Raspberry Pi
• Software: OpenCat open-source firmware (GitHub)

The OpenCat firmware is fully open source, enabling students to modify gaits, add sensors, and develop custom behaviours.

Use Cases

The Bittle X is used in school robotics clubs, university introductory robotics courses, and hobbyist projects. It is well-suited to teaching inverse kinematics, gait generation, and embedded programming. It cannot carry meaningful payload or operate outdoors.

Buying Used

Used Bittle X units appear on eBay UK and hobbyist forums. Pricing ranges from £150 to £280. Check that all servo motors operate smoothly and that the NyBoard controller is functioning. The open-source firmware is well-documented and straightforward to reinstall if needed.

Alternatives to Consider

• Unitree Go2 Air: Full-size quadruped with lidar and ROS support, for $1,100.
• Unitree Go1 (used): Larger research platform at modest secondhand prices.
• Custom Arduino quadruped kits: Lower-cost alternatives for pure electronics learning.

The Bittle X differs from the original Bittle by adding a stronger servo specification and improved joint range of motion, enabling more dynamic gaits. Petoi's OpenCat firmware implements pre-programmed behaviours including trot, pace, and bound gaits as well as a REST API for remote command via WiFi or Bluetooth. This makes it accessible for web-based programming exercises without requiring embedded C experience. Schools use it to introduce inverse kinematics, PID control, and sensor fusion in a hands-on format.