h a l f b a k e r yThis ain't rocket surgery.
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Imagine an array of permanent magnets; each magnet is rotatably mounted on a flat base so that the north-south poles spin around.
The magnets are separated at a distance such they can affect the adjacent magnets.
If the array is a triangular array, the magnets will be in an unstable (or maybe meta-stable)
configuration. If one magnet is rotated, adjacent magnets will be rotated; the effect will ripple through the array of magnets. See link to frustrated magnetism.
The surface of each magnet is coloured; e.g. three segments, each segment a different colour.
This would be an interesting display for a science museum. It could be mounted vertically and make a piece of dynamic art.
Frustrated magnetism
https://en.wikipedi...ated_magnetism.webm
[xaviergisz, Sep 06 2022]
Quantum spin liquid
https://en.wikipedi...Quantum_spin_liquid
[xaviergisz, Sep 06 2022]
Buncha these would be cheap
https://www.kjmagne...il.asp?prod=R424DIA
[a1, Sep 06 2022]
Perpetual Motion with spinning magnets.
https://youtu.be/BSdSDfOWbNs
Be sure to watch to the end. [a1, Sep 06 2022]
Frustrated magnet display
https://www.youtube...watch?v=CD-t5yHT7ME
[a1, Sep 06 2022]
Ripple through magnets
https://youtu.be/DNhcQVjbRgo?t=140
[xaviergisz, Jan 03 2023]
Prototype
https://photos.app....l/zSzMQLBEYHqEJLgR7
[xaviergisz, Feb 11 2023]
[link]
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Just checking; is the triangle in which the magnets are arrayed in the same plane in which they are free to rotate, and perpendicular to their axes of rotation? |
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Do they have to be bar magnets? The linked round ones are pretty small and wouldn't make much of an art display - but are really low cost for proof of concept. |
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Interesting. Artistic and sciency. [+] |
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Got to be a way to incorporate into a perpetual motion machine. Hmm. |
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My brain gave out at visualizing the second order magnetic field interactions. Can someone please just tell me how it ends? |
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[xaviergisz], does the "frustrated magnet display" link look like what you had in mind? |
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Nice find, a1. Similar concept, but different to what I had in mind. The "frustrated magnet display" has the axes of rotation parallel to the base. My idea is the axes of rotation are perpendicular to the base. |
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I'm thinking if getting a sheet of plastic laser cut with an array of holes which each contain a diametrically magnetised cylindrical magnet. A sheet of clear plastic over the top and bottom will keep the magnets in place while allowing them to freely rotate. |
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// diametrically magnetised cylindrical magnet // |
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Yep, that's what I was thinking with my first link from KJM. But the tiny cheap ones might not make a very impressive display. And the big ones are devilishly expensive, at $6.66 each for a tube 1" in diameter an 1/4" thick. |
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Edit: Oh wait - I imagined tubular magnets on a kind of pegboard - thinking you'd put each one onto its own spindle. Your embodiment would be better and allow for cheaper magnets. |
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I've got about 750 3mm (diameter) x 6mm (length) diametric cylindrical magnets (which I bought for another project). They cost 10 cents each. My idea at the moment is: I'll get a ring shaped housing (outer diameter about 8mm) laser cut that each magnet can fit snugly into. Then I'll get a "David's star" array with about 400 8.05mm holes (10mm hole separation) laser cut. |
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<fascinated but without input> (+) |
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The magnet display is for kids. Adults use properly boring displays like static Klein bottles and Newton's Cradle. |
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I finally got around to making a prototype (see photo in link). Each magnet has a cap glued on; the top of the cap is laser etched with an arrow. The rotating magnet 'ripple' only propagates to a few magnets and stops. There is too much friction between each magnet and the corresponding hole. |
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So... an instantly adjustable Halbach array? |
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[xaviergisz] I am always impressed when someone here really builds the things they imagine! Does it behave as you expected? |
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[a1], the result of the prototype was disappointing. I'm now wondering if the friction problem could be overcome by cleaning the magnets of the dry superglue that has formed a thin layer on some areas of the magnets. For the next prototype I think I would mount the magnets in a (non-ferromagnetic) bearings to reduce the friction. |
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