I'd love to see a small Prince Rupert's drop for a tip and a ruby/sapphire spinning surface - you'd need to make a ton of drops, probably, but having a round, nearly spherical contact geometry and super smooth surface seems like a winning combo.
Awesome!
For now. When that changes soon, smart people will start having two phones, one of which runs Linux or GrapheneOS.
At around the end of the fidget spinner craze I thought "but what would it take to make it spin by its own?" And it turned out, not much. Just put one magnet at each of the three ends, and have some pulsating magnet near it (next to it, or under it hidden in some kind of base), and there! you have a basic electric motor that seems entirely magical.
It was a really fun experiment; I even toyed with doing a small production run but by the time I was almost ready the craze had passed.
Did make me wonder if you could build a solid state one using well-timed pulses through an electromagnet that provide torque through the field interaction with the earth's magnetic field.
Not much torque available there obviously, but on a per-revolution basis you don't need much.
To implement this, I think you'd first want to test in a controlled environment with a larger magnetic field and then gradually turn down the applied field until it is Earth-like. I am honestly unsure whether you could practically get there, so earlier I used the words "maybe could", but humans are crazy so I appended the "probably".
This would be a fun YouTube video to watch.
https://hackaday.com/2021/12/01/supersonic-projectile-exceed...
The material science discussion in these comments is fascinating. Never thought about how the contact point geometry matters so much. Diamond tip makes intuitive sense for hardness, but then you need something it can spin on without scratching...
For instance, a spinning top is already mentioned in the Iliad of Homer, where he compares the rotation of a certain warrior after receiving a very strong off-center strike with the rotation of a spinning top ("strombo-" in Ancient Greek).
And now that I think a bit further, I might just be imagining a more complicated version of one of those crabwalk spinny metal ones..
If you could develop a self-starting top capable of remote controlled translational movement you would get non-wheeled weight bonuses up to 2x in most competitions.
I am curious:
* will spinning *direction* (clockwise, or anti-clockwise) effect spinning duration?
* and being in Northern Hemisphere vs South Hemisphere (Coriolis effect)?
If the axis of the spinning top is stationary relatively to Earth, there are no Coriolis forces.
For a big spinning top, there could be non-negligible periodic Coriolis forces acting on the periphery of the spinning top, but they would be compensated by the rigidity of the top and in any case their average over a complete rotation of the top would be null.
How long would a better battery go here?
I'm curious what the jump from 2-> 40+ hours requires
Guess it's cnc milled, maybe that's part of it. Increase mass of the thing? Idk
