The meaning of Inception’s ending famously revolves around a top which spins forever in dreams, but in real life comes to a stop like any other top. Any other top, that is, except for [Aaed Musa]’s self-spinning top, which can continuously spin for about two hours before coming to a stop.
The one constraint was that every functional component had to be contained within the top’s shell, and [Aaed]’s first approach was to build a reaction wheel into the top. When a motor accelerates a weighted wheel, conservation of angular momentum applies an equal and opposite torque to the motor. The problem is that motors eventually reach a top speed and stop accelerating, which puts an end to the torque. This is known as saturation, and the only way to desaturate a reaction wheel is to slow it down, which counteracts the originally generated torque. [Aaed] originally planned to mount the motor in a one-way bearing, which would let it bleed off speed without producing torque against the rest of the top, but it was rather choppy in practice.
The solution occurred to [Aaed] while watching the aforementioned final scene, when it occurred to him that the wobbling of a top could actually generate rotation. A prototype proved that an off-center weight rotating at a constant speed did successfully spin the top by rotating the center of mass, and after that, it was a matter of incremental testing and improvement. A higher moment of inertia worked better, as did a lower center of gravity and a tip made from a hard, low-friction silicon nitride ball bearing. He made housings out of both 3D-printed plastic and CNC-milled aluminium, which each contained a tiny brushless motor, an electric speed controller, a microcontroller, and a small rechargeable lithium battery.
If you allow for external power, you can make the top itself the rotor of a motor, and drive it from a base. Alternatively, if you levitate your top in a vacuum, it could spin for longer than recorded history.
His totem wasn’t the top. The top is meaningless. That was his wife’s totem.
Heheheheh, interesting…
I already saw this video on youtube case it recommended me. I see hackaday everyday, and of course spend too much time everyday on youtube too, but Im always curious about that fact, that so often hackaday talks about a project I already saw on youtube. It makes me think about the recomendation engine and the audience niche, but I dont know how it can happen, given the amount of available videos, or what it really means.
I suppose it also happens for many of you too
And sorry to talk, even more in the first message, from a topic different topic than the project mentioned itself
Mee too. The same.
I use a firefox extension called “unhook”. It hides all recommended videos on youtube. Your homepage when you open youtube is a blank page now, with no videos
Its great for me, it stops me from going down the multi hour long rabbit hole of randomly recommended videos
Also yes, hackaday+youtube algo is definitely, somehow, making a feedback loop that feeds us with the same kind of stuff. I can’t prove it, but I’m pretty sure all hackaday users are recommended quite similar stuff
This, in spades. YouTube will recommend the videos to you as soon as they show up. Here at Hackaday, we have a person who watches the video, decides whether it was worth his/her time, and then writes it up.
The YT recommendation algorithm is faster, but it’s also aimed at getting you to watch the maximum number of videos. There are a lot of misses. (I get “free energy” videos pushed on me all the time.)
The Hackaday algorithm… is people, and we don’t have any interest in how many YT videos you watch. We only recommend vids we actually liked. We believe this results in a significantly higher signal/noise ratio, although at the expense of speed.
No matter how often I mark “do not recommend channel” and “not interested” I keep getting movie trailers and fake movie trailers. Also when I type something in search engine I get group of results that repeat over and over and some of them are not even related to the word I typed in search engine. Recommendations are 90% miss – they spy on me, process my data and fail to deliver proper advert or movie. In the past it was quite opposite.
I also see lots of recomendations that Im not interested in. But I dont think they make such big mistakes, they play this game so many times a day. Maybe such videos still get more traffic than others, in average, even most of the times fail, or maybe they simply want to low your bar so the next recomended one looks cooler…Or maybe they know you will not play them and want to test if you are a bot…Nobody knows.
About hackaday entries curation, I dont have any issue with it, even it removes some surprise effect, just wanted to know if this happens to other users too.
I had one of these back in the 80’s. https://www.youtube.com/watch?v=NRlwwAax8Ik
It was mentioned in the video and stated that he wanted all of the mechanics and electronics inside the top.
I believe the commercial versions of these do not use a rotational motor, but a pizio movement in line with the axes of rotation of the top. This adds energy to the system because of slight procession and self correcting off axis acceleration. I have one that will spin for hours on any surface and it definitely does not have a motor inside.
https://www.amazon.com/s?k=electric+spinning+top
Nice, truly self-contained “perpetual” top. Have you thought of making an induction/eddy-current top, which would have the top as rotor and metal plate as stator? It would be relatively silent, with no moving part but the top itself… and might (or might not) run longer.
My previous comment was summarily deleted, no doubt because I included statements less than 100% complimentary, and sartorial choice comments.
In short, don’t watch the video expecting to learn how to understand and exploit gyroscopic precession to make a top spin.
Though there’s a bit of lip service to the math, it’s just thrown out. There’s no prediction of performance, no actual experimental testing against any theory — just trying seemingly random iterations around an idea that either wasn’t clearly articulated, or doesn’t make a lot of sense to begin with.
The video shows many iterations of trying stuff and finally lands on a combination of things that sort-of works for a while. But there is no explanation of how it should work, nor even anything beyond conjecture of why it more-or-less works in the end.
I had really hoped there was some meat in this one, because it’s a neat idea that deserves some good exposition by someone who understands it.
I’ve had HaD comments go into some weird limbo where I was certain it was deleted only for it to show up some time later, sometimes hours or a day. Yours maybe did that.
Back on topic- I had some kind of gyro wrist strengthening device decades ago when I was rock climbing a lot. It was like a sphere with a gyro in it. You would flick it to spin it up then sort of precess it yourself to get it to wind up to an impressive RPM. I suspect that’s how this thing “works” and I’m certain if I wanted to actually figure that out I could but these videos are all like you noted- the thing is not the thing- the Thing is clicks and revenue generation. That he sort of accomplished something is nearly irrelevant.
It’s not all that important my man…we all got more important things on our minds…a baseball cap can be the reason why someone watches this
Excellent, now let’s put those into the compact flywheel batteries the average Sam’s budget can afford … now let’s shrink those down to the thickness of a laptop … then cell phone …