The $99 Robot You Can’t (Easily) Break

Robotics isn’t an easy field to get started in. It requires expertise in many areas, ranging from software engineering and mathematics to mechanical design and electronics. To make matters worse, capable robots also tend to be extremely expensive. When looking for a platform to experiment with, it can feel like there are two options: junky toys that can’t do much of anything, or robots you can’t afford without selling your house.

Fortunately, if you don’t mind doing some work yourself, James Patten has come up with another solution. He has designed an open source Stewart platform built from inexpensive, accessible components — and he’s released a video tutorial to teach you how to build it.

The robot, named Stewy V2, is a compact and mobile Stewart platform designed specifically as a learning tool for robotics enthusiasts. This second iteration focuses on improving affordability, durability, and ease of assembly—three areas that often discourage newcomers from diving deeper into the field.

Stewy V2 is powered by an ESP32 microcontroller, which handles both onboard processing and wireless communication. The platform uses six high-quality metal-geared servos arranged in a classic Stewart platform configuration, allowing for precise movement in six degrees of freedom. This enables the robot to tilt, rotate, and translate in space, making it an ideal system for experimenting with kinematics and control algorithms.

Off-the-shelf components like distance sensors and a joystick provide interactivity, while custom PCBs simplify the electronics. Instead of complex soldering, users can rely on plug-and-play connectors, making assembly far less intimidating for beginners.

Mechanically, the design introduces several clever innovations. One interesting feature is the use of “captured parts” during 3D printing. By pausing prints mid-process, components such as bearings and servo horns can be embedded directly into the structure, reducing the need for additional fasteners and improving precision. The parts are also designed to print without supports, using stepped geometries that allow clean bridging.

Another key feature is the use of magnetic joints in the robot’s arms. These joints are designed to break away under excessive force. Rather than snapping plastic components during a crash, the arms simply detach and can be snapped back into place. This makes the platform highly resilient—and ideal for experimentation, where mistakes are inevitable.

On the software side, the system uses Wi-Fi and UDP communication between modules, enabling low-latency control. Combined with its fully open source design, created in a cloud-based CAD environment, users are encouraged to modify, extend, and customize the robot to suit their own projects.

Stewy V2 is being offered as a kit for $99, or fully assembled for $179.