Why I Built This
This project started as something simple: I wanted to build a toy for my kids. A real, walking, six-legged robot they could hold, control, and be genuinely excited about.
But as it grew across three generations — through underpowered servos, violent jitter, and a complete chassis redesign — it became something more. Hexapod Mochi is now a platform I hope my kids will one day use to learn the skills that matter: 3D printing, electronics, coding, and the engineering mindset of iterating until something actually works.
Every design flaw, every failed prototype, and every hard-won fix is part of the story. That’s the whole point.
📚 Build Your Own
The Foundation
The Ambitious Baseline
Every great robotics project begins with a simple question: Can I make this move smoothly? The first version was a proof of concept to test leg geometry and basic multi-directional locomotion.
Physics caught up quickly. Built around standard MG90S micro servos, the robot was fighting an uphill battle — the servos were simply too weak for the combined weight and dynamic forces of walking. The internal wiring layout was clunky and prone to tangling.
The Quest for Power
The Battle Against Jitter
To solve v1’s power deficit, v2 took a brute-force approach. The system was upgraded to support either a Raspberry Pi Pico or an ESP32, and the legs were completely redesigned to house beefier 21g servos.
In practice, high-quality 21g servos proved frustratingly difficult to source. Sub-par components caused a massive problem: terrible, violent jittering. The robot had the power to lift itself but spent more time shaking than walking.
Refinement & Redesign
Form, Function, and the Perfect Fit
The breakthrough came with the MG92B servo — the strongest micro servo available that still fits a compact form factor. It delivers high torque without the massive footprint or violent jitter of v2.
With hardware dialed in, the chassis was radically transformed. The rectangular body gave way to a sleek circular layout, improving symmetry, multidirectional leg clearance, and lending the robot a distinctly friendly personality. Meet Mochi.
⚙️ Design Philosophy
Mochi is a six-legged, WiFi-enabled crawler with 18 degrees of freedom and a circular body that balances weight, simplifies wiring, and improves stability. Driven by an ESP32 over a built-in WiFi access point, it supports over-the-air firmware updates and full gait customization. Every structural decision was deliberate.
Layer Orientation
Print layers align with load directions, distributing stress along their length to prevent delamination under walking forces.
Reinforced Joints
Leg segments and servo mounts feature strengthened connection points that spread loads and minimize stress concentrations.
Circular Frame
The round body optimizes the weight-to-rigidity ratio for stable locomotion and even servo load distribution across all six legs.
Modular Assembly
Interlocking components reduce adhesive dependency and make repairs or upgrades straightforward without specialized tools.
Material Flexibility
Geometry is optimized to perform reliably with standard PLA or PETG, maintaining durability under repeated dynamic stress.
Full Control Stack
Includes a BOM, wiring diagrams, gait look-up tables, path generation tools, and an Android app for point-and-go control.