Drag a slider. Watch the gear ratio change in real time. Understand why cycloidal drives beat planetary gears in half the space — in 5 minutes.
No spam. Just the demo link when it's ready.
When a 15-year-old's hand-built cycloidal gearbox hit 314 points on Hacker News with 102 comments, it wasn't just a feel-good story. It exposed a gap: thousands of robotics enthusiasts, 3D printing hobbyists, and mechanical engineering students are hungry to understand this elegant mechanism — but they're stuck with static diagrams and dense Wikipedia formulas. The HN thread was full of questions like "How does the eccentric bearing work?" and "Why is it so compact?" — clear signals of untapped learning demand.
Existing solutions fail to bridge the gap. YouTube videos are passive — you can't pause reality to inspect a tooth profile. Wikipedia's math is correct but impenetrable without a visualization. Open-source CAD models require heavy software and offer no explanation of the underlying kinematics. There's no interactive way to grasp the core insight: how a cycloidal disc with one fewer tooth than the ring gear creates a speed reduction through pure rolling contact.
The timing is perfect. The HN signal shows a spike in interest, and the maker community is growing — more people are 3D printing robot joints, building actuators, and designing compact drives. Yet no dedicated interactive tool exists. This is the moment to give them a hands-on mental model, not just a video. A tool that lets you drag sliders and see the gear ratio change instantly — that's the missing piece.
Start with the core variables: the number of cycloidal lobes, the eccentricity, and the pin count. Drag the sliders to see how each parameter influences the gear ratio and the overall geometry. The 3D model updates instantly, giving you immediate feedback on your design choices.
Rotate the view and zoom in to see exactly how the cycloidal disc interacts with the ring pins. The animation shows the eccentric motion and the rolling contact that creates the speed reduction. You'll finally see why a cycloidal drive is so compact compared to a planetary gear of the same ratio.
A side-by-side panel shows a cycloidal drive and a planetary gear set with the same volume. You'll see the torque density advantage in real time — the cycloidal design delivers higher torque in a smaller package. This is the key insight that makes cycloidal drives the go-to choice for robot joints and precision actuators.
Adjust the number of lobes, pin count, and eccentricity with intuitive sliders. The gear ratio updates instantly, helping you build a mental model of how each variable affects the drive's performance. No static diagrams — you see the cause and effect immediately.
Rotate the camera, zoom into the contact points, and watch the cycloidal disc mesh with the ring pins. The 3D animation reveals the rolling contact that makes this gearbox so efficient and compact. You'll finally see the mechanism from every angle, not just a flat cross-section.
See a head-to-head comparison between a cycloidal drive and a planetary gear of the same volume. The torque density difference becomes obvious — cycloidal wins by a significant margin. This is the key insight that drives its adoption in modern robotics and precision machinery.