[HN Gopher] A clever "perpetual motion" device [video]
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A clever "perpetual motion" device [video]
Author : ed_westin
Score : 115 points
Date : 2023-09-14 18:44 UTC (4 hours ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| p1mrx wrote:
| Be aware that most of the cheap knockoffs just use a motorized
| wheel. For example, see the videos on
| https://www.amazon.com/dp/B09VTJ4LZ8/#ive-videos-for-this-pr...
| BugsJustFindMe wrote:
| They also use diagrams showing the ball traveling the wrong
| way. https://imgur.com/a/o3sHFhX
| tempestn wrote:
| Huh, I'd always assumed the ball simply closed a circuit when it
| rode on the rails, and that's how it knew when to turn the magnet
| on and off, with suitable delays. It does seem to me you could
| still do it that way, but it'd probably be more difficult.
| [deleted]
| owenpalmer wrote:
| Steve Mould is top-notch
| martinmunk wrote:
| This one is pretty good, but I usually steer clear of his
| videos. Topics are pretty on point for my interests, be he just
| seem... Too full of himself? I don't want to be mean in any
| way, but if someone agrees maybe they can put a finger on what
| it is
| owenpalmer wrote:
| Too full of himself? I'm not sure I understand, can you give
| an example?
| Cthulhu_ wrote:
| I didn't get the impression he's too full of himself, but he
| was confident for sure. That's not being full of oneself
| though, that's making a video interesting, confidence, and
| not filling the space with caveats or self-deprecation.
| legohead wrote:
| I feel like your mind must have confused two people. Steve is
| very down to Earth.
|
| Maybe his youtube-battle with ElectroBOOM turned you off?
| Where he was pretty convinced he was right about the chain
| fountain.
| masklinn wrote:
| Nah I always have the same impression, even though I've
| been watching for years (long before the chain thing), and
| I can see the janky setups trying to figure things out.
|
| I think it's mostly the voice / accent, to me it...
| _sounds_ sneery?
| masklinn wrote:
| His voice and presentation style do give me the same feeling.
| I don't know why. Same with Mark Rober.
|
| But the actual content is the opposite. It's really quite
| strange.
| martinmunk wrote:
| Yeah, I think I can see the link to Mark Rober. Although
| not at all to the same degree. Maybe it's the way of
| "acting dumb" in order to progress the discovery process,
| but a face that they know full well (obviously) that he
| knows what's going on? Essentially talking down to the
| audience?
|
| Not sure. My first attempt at phrasing it did not get my
| feeling across well.
| Bellend wrote:
| I don't know him but I feel he is a bit tongue-in-cheek with
| humour. As far as I remember, he did comedy and was also good
| with education with kids. I don't imagine meeting him and him
| coming across as full of himself though. I feel I could
| approach him in a pub and he would have good banter.
| cycomanic wrote:
| What is your background? I know that many Americans perceive
| a British accent as snobbish/arrogant (this is often used in
| Hollywood movies as well). So maybe it's just that?
| phailhaus wrote:
| This one is pretty representative of what his videos are
| like. Could be that you got a skewed first impression? Once
| you watch a few of them, you can see he's pretty genuine.
| Retr0id wrote:
| There are a few youtubers that come to mind who fit this
| description, but Steve Mould is not one of them.
| londons_explore wrote:
| This circuit is awfully complex.... it's possible to do the same
| with a far simpler circuit if you use the same coil for sensing
| and accelerating the ball.
|
| A small microcontroller could do both - perhaps even with low
| enough power that the whole circuit could stay turned on for
| years on a charge (when not flinging the ball).
|
| Looking at the total energy you need to impart on the ball, you
| should be able to do that with a far smaller coil and many fewer
| capacitors as long as you have a suitably shaped steel core to
| keep the flux path low. I suspect you might be able to do it with
| no capacitors at all, since modern lithium cells are perfectly
| happy to deliver 100 amps for a few milliseconds.
| ape4 wrote:
| An entire microcontroller to run an approx 3-line program?
| polishdude20 wrote:
| Cheaper than to have a microcontroller that results in a
| smaller PCB vs discrete components that make the PCB bigger.
| NavinF wrote:
| That's very common. Look at all the $0.03 microcontrollers on
| LCSC. They save time, money, and board space.
| londons_explore wrote:
| Using a single coil, the microcontroller program is pretty
| complicated. It needs to pulse the coil very briefly on a
| regular basis and measure the resonant frequency.
|
| If you do the capacitor-less design, you might want to have a
| steel core with sawtooth top, and then use software to
| measure the position of the ball relative to each tooth and
| turn the coil on while the ball is heading towards a tooth
| and off when the ball is heading away. That allows the energy
| to be extracted from the battery slower.
|
| You might also choose to have your coil driven by an
| h-bridge. That means you can put the energy from the magnetic
| field that builds up in the steel core back into the battery
| between each 'tooth'. That should dramatically increase
| energy efficiency, allowing you to use a smaller (cheaper,
| lighter, more eco friendly) cell or have the battery last
| longer. To do that, you'll need current sensing too.
| amelius wrote:
| You say that the circuit is complex, but it's the other way
| around.
|
| Its simplicity is the cause of the high component count.
| pxndx wrote:
| Lost it at the "through the magic of buying two of them" bit!
| dageshi wrote:
| https://www.youtube.com/watch?v=CZs-YcmxyUw
| [deleted]
| debesyla wrote:
| That, by the way, is a reference to another great channel -
| Technology Connections:
| https://youtube.com/@TechnologyConnections
| divbzero wrote:
| I wonder if the creator of this device William Le [1] has managed
| to make this his full-time endeavor.
|
| [1]: https://www.etsy.com/shop/backtonaturedecor
| koromak wrote:
| Damn I kinda want to build little doohickeys and sell them on
| etsy instead of going to work every morning
| luma wrote:
| Nothing stopping you! I have git and printables etc accounts
| full of stuff I've designed and shared, but some folks might
| just want the finished thing so awhile back I hung out my hat
| and started a small shop selling the widgets I design and share
| for free.
|
| Turns out a lot of people just want the thing, I can give the
| plans away and still make some extra on the side by making a
| few to sell.
|
| I'm incredibly far away from being able to quit my job over
| this, but it has turned a few of my hobbies into slightly net-
| profitable ventures instead of money holes and the result is a
| well appointed shop to spend my free time playing around with
| new ideas.
|
| My advice: give it a shot. There's nearly zero up front cost
| and if nothing else, you'll probably learn a bit.
| Workaccount2 wrote:
| I can tell you that this has two possible outcomes:
|
| 1. You don't sell enough to get by.
|
| 2. You sell enough for Chinese knock-offs to come in and offer
| a good-enough clone product for 1/3 your raw material cost.
|
| Being a first world tiny shop in hardware is near impossible.
| masklinn wrote:
| (3) you make good looking gizmos which are not really worth
| copying seems to be the niche of "William". Apparently the
| slides were about 150, and they're externally simple but good
| looking. They're out of stock but the shop has neat kinetic
| sculpture for high hundreds.
|
| Could you get plastic versions for a third the price?
| Absolutely. _Would_ you? Hell nah. I could see kits of spare
| parts to print and build your own, maybe, but not ready made.
| itigtohft wrote:
| If you search for "perpetual motion machine" you can find a
| ton of cheap knockoffs of this device. You can get a badly
| made wooden knockoff for $50 or quite a bit less?
| newaccount74 wrote:
| There are a bunch of tiny hardware shops in the audio
| community that seem to be doing fine, for example
| https://neurochrome.com/
|
| Of course, running a small business like this is not easy,
| but it's not impossible either.
| [deleted]
| tnecniv wrote:
| Well then building doohickeys would be your new "going to work"
| semireg wrote:
| Business is a great way to ruin a hobby.
| yantrams wrote:
| Brings back childhood memories. Enjoyed reading about these and
| the accompanying illustrations as a kid from the excellent book
| Physics for Entertainment by Yakov Perelman. Nirantara Chalana
| Yantralu they were called in Telugu translation.
| facu17y wrote:
| I had the Arabic translated edition of that book! same fond
| memories!
| tantony wrote:
| > Physics for Entertainment by Yakov Perelman
|
| I read the same in Malayalam! That book was one of my earliest
| introductions to practical physics. He deconstructs pretty much
| all the early "perpetual machine" designs in the book.
|
| I also particularly remember the chapter with the experiments
| with soap bubbles as being very interesting as a kid.
| rendall wrote:
| How delightful. I was 99% sure even before I clicked that it
| would be Steve Mould.
|
| Loved his parody of the fixed grin of Technology Connections.
| thefourthchime wrote:
| Me too!
| Try1275 wrote:
| The video is worth just for his expression at 1:07. Highly
| recommended. Have no interest in the topic and watched the whole
| thing!
| [deleted]
| iamjackg wrote:
| For those who don't know, it's a reference to Technology
| Connections[0], another incredible YouTube channel. Alec, the
| host, is very fond of that bit[1].
|
| [0] https://youtube.com/@TechnologyConnections [1]
| https://www.youtube.com/watch?v=CZs-YcmxyUw
| ChrisClark wrote:
| Hah yeah, for some reason that line never gets old for me.
| masklinn wrote:
| It's short, it's snappy, and it's only deployed
| appropriately (by Alec, and by Steve here), so it stays
| fresh and not overdone.
|
| And other similarly nice recurring gag is Tasting History's
| hardtack.
| russdill wrote:
| Oh my gosh, the green screen
| em-bee wrote:
| i have only seen a few of alec's videos, but i immediately
| recognized this as familiar, wondering "hey, that's a
| different guy"
| maerF0x0 wrote:
| Could this work as a magnetic rail with earth magnets? Would that
| not require any batteries then?
| p1mrx wrote:
| What do you propose to use as an energy source?
| [deleted]
| ugh123 wrote:
| How would you "switch off" the magnets as the train approaches
| so as to allow it to pass with its newly gotten energy?
| gus_massa wrote:
| I'm not sure if the GP is proposing a railgun. In any case, I
| propose a railgun version.
| https://en.wikipedia.org/wiki/Railgun
| stavros wrote:
| Ooh, I'd love to find one of these on Ali, but their search is
| betraying me currently.
| comicjk wrote:
| Was anyone else hoping it would detect the ball by simply
| completing a circuit (since the rails are metal and so is the
| ball)? Then it could give a magnetic tug after an appropriate
| time. Maybe this would be flaky because of the poor contact
| between rails and a rolling ball, but an inductive proximity
| sensor feels like overkill.
| angry_moose wrote:
| It probably wouldn't work nearly as well.
|
| It looks like the rails are already a complete circuit - I
| think they're a single piece of wire that is bent at the end to
| make a loop, and there are a couple lateral braces soldered on
| to keep them properly spaced.
|
| You'd have to split the rails into two pieces and replace the
| lateral braces with something nonconductive (plastic) which
| wouldn't look nearly as nice; and the device would be a lot
| more prone to going out of calibration if the spacing drifted.
|
| Its probably possible but there's a lot of downsides to save $2
| on a sensor, some of which will be eaten up elsewhere as it
| will add some additional parts.
|
| Edit: It would also somewhat spoil the magic, as that's the
| first thing most of us would think of (I certainly did).
| johnyzee wrote:
| This got me wondering if it could be made to be entirely
| mechanical. Like, the approaching ball triggers something to move
| in front of the magnet 'switching it off', then slides away again
| when the ball has passed, ready for the next run.
|
| I think I just invented perpetual motion...
| tempestn wrote:
| No reason you couldn't do that as long as you just mean the
| actuation is purely mechanical. You'd still need an
| electromagnet and power source though, as it only works if you
| can turn the magnet on and off.
| MetallicDragon wrote:
| Any mechanism that could switch the magnet on and off would
| require energy. E.g. you could put a magnet next to it with
| opposite poles, which would mostly cancel out the magnetic
| field, but would require a lot of force to push them together,
| which is work, and thus requires energy.
| p1mrx wrote:
| What do you propose to use as an energy source?
| austinjp wrote:
| Just build a second machine to power the first!
| _a_a_a_ wrote:
| Excellent presentation, no dumb graphics, witticism, silly voices
| or stupid faces pulled etc, just nice clean explanation.
|
| Nice toy too. I'd get one but I'd turn it on 3 times then get
| bored and give it away.
| zht wrote:
| it's funny because there's another comment saying they really
| enjoy the stupid face at 1:07
| Cthulhu_ wrote:
| I like it as a desk toy, like the row of balls or things like
| that.
| phelm wrote:
| I thought it was going to be a railgun
| Cthulhu_ wrote:
| It can be if the magnet's strong enough!
| oldandtired wrote:
| Steve makes an interesting statement when he says "we know that
| perpetual motion is not possible". Yet we have a modification to
| the general cosmological view with the theoretical entity "dark
| energy" which if you consider what is said about it properties,
| it provides a means of creating a "perpetual motion" environment.
|
| So what can we say: Does perpetual motion exist or not?
| mr_mitm wrote:
| Energy is not globally conserved in an expanding universe, dark
| energy existing or not.
|
| https://www.preposterousuniverse.com/blog/2010/02/22/energy-...
|
| https://physics.stackexchange.com/questions/259759/conservat...
|
| https://twitter.com/WKCosmo/status/1303134701180325890?t=pv5...
|
| Obviously the guy in the video was making the implicit
| assumption that we are talking about local experiments.
| n2d4 wrote:
| The accepted solution in the second link claims your other
| two links are wrong:
|
| > Some people claim incorrectly that energy is not conserved
| in an expanding universe because space-time is not static.
| The law of Energy conservation is derived from Noether's
| theorem when the dynamical equations are unchanged with time.
| These people confuse the invariance of the equations with the
| invariance of the solution. Space-time changes but the
| equations obeyed by the expanding universe do not change.
| Space-time cannot be treated as a background, its dynamics
| must be included when deriving the enrgy equations via
| Noether's theorem. This leads to the equations given above
| which show that energy is indeed conserved.
| dist-epoch wrote:
| You are being pedantic.
|
| If you want to consider dark energy perpetual motion, sure, but
| then it's excluded from the "we know that perpetual motion is
| not possible" rule.
|
| "we know that perpetual motion is not possible" is based on the
| fact that you can't break the laws of physics, which perpetual
| motion is doing, but if dark energy is part of physics, it
| can't break those laws by definition.
| Cthulhu_ wrote:
| What makes you think dark energy is "a means of creating a
| perpetual motion envrionment" though? I've never heard that
| claim made.
|
| I mean personally I think the theory of dark matter / energy is
| a patch for the perceptions not matching up with the theories,
| but that's besides the point.
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