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Comment by funkyy | Hacker News Reader

The one thing that prevents them from entering customer market in every day use is that magnets can affect many things.

Simple example - I had cover for my phone with a magnet closure. It wasnt affecting my phone in any way, but few times I put parking card next to it and it wiped out all the information from it forcing me to chasing parking office to get it re-printed.

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But wouldn't this be the solution to your problem? If the pole reversals are tightly packed, it looks like the field lines could be designed to not affect other objects, even in close proximity.

As long as facing right direction. Its just one example and actually quite good - I would keep initially the ticket inside of the case, so it would come close to magnet anyways.

When I was at uni we spent some time in the lab playing around with Magneto-optical film and polarized light, it was supposed to demo the Kerr Effect. I had fun with an old floppy disk - you could bring a bar magnet close to the disk's film and watch the magnetic domains flip under the microscope.

Would be pretty cool to print some patterns using this technology and view it the same way.

> Kerr Effect

Applied Science (which has many great videos) recently did that demonstration using an old magneto-optical removable disk. He was able to get a very nice example of the effect that is visible with the naked eye.

https://www.youtube.com/watch?v=UTquUbvzJII

If you like that video, the previous video on the Faraday effect is really cool; I had no idea a solenoid rotates light polarization.

https://www.youtube.com/watch?v=XhU-nNiAgtI

Supposedly this reduces the distance to affect sensitive electronics/cards.

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