Real-Life Zonai Stabilizer Keeps Things Upright

There is a lot to love about Tears of the Kingdom. It carries over everything we all adored about Breath of the Wild, then went and added a bunch of cool new mechanics. The most notable of the new mechanics is fusing, which lets you use magical glue to stick objects to each other. To make creations dynamic, TotK also introduced Zonai devices like rockets, powered wheels, thrust fans, and more. One of those Zonai devices, the stabilizer, will always stay upright when active — and will force any attached object upright, too. Proving his mastery of physics, James Bruton recreated the Zonai stabilizer from Tears of the Kingdom.

While the game never explains how the Zonai devices work, there is really only one way to make something like a Zonai stabilizer and that is with gyroscopes — though reaction wheels might work, too. Thanks to the conservation of angular momentum, a spinning gyroscope will resist any force that pushes it off its axis. You can experience this yourself with a handheld gyroscope ball meant for exercise. When it is spinning, you will find it difficult to rotate the ball. The greater the mass or speed of rotation, the stronger the effect. So to get a very substantial effect, you will want to spin something heavy at a high speed.

For this project, Bruton wanted to maximize the effect at a reasonable cost and chose to use automotive disc brake rotors for the spinning mass wheel. He needed two of those to construct two gyroscopes in order to keep the stabilizer from tipping to either side. A powerful brushless DC motor spins each rotor under the control of an Arduino Mega 2560 board. A geared DC motor pivots the gyroscopes as necessary to counteract any tipping.

The entire contraption is roughly the same size as the in-game Zonai stabilizer. Most of the mechanical parts were 3D-printed and some 2020 aluminum extrusion makes up the frame. Power comes from large hobby lithium battery packs. The Arduino uses a PID feedback loop to compensate for tipping without ending up in out-of-control oscillations.

This real-life Zonai stabilizer works pretty well. It can balance itself and even small a small scooter. But it can only stop tipping to either side and more gyroscopes would be necessary to keep it from tipping forward or backward. It also can't handle nearly as much mass as the in-game Zonai stabilizers, which seem to have infinite strength. But even so, we're impressed and delighted by this build.