Tangle-free magnetic USB cables are here | Hacker News Reader

Tangle-free magnetic USB cables are here

theverge.com

38 pointsTomte51 comments

Okay, I need a smart person to explain to me why magnets don’t destroy my technology anymore. I swear growing up I was told that even looking at a magnet would wipe my drives and turn my screen into rainbows. Now we’re sticking them to our phones and iPads and throwing them in our laptop bags…what happened? Was it all anti-magnetic propaganda?

We stopped using HDDs and CRTs, and started using SSDs and LCDs.

Or more broadly, we stopped using magnetic-based storage & display technology. Hence why random external magents were bad for those things, they used magnetic fields for their operation so other magnets would corrupt things.

In principle, magnets and floppy discs didn't mix, any more than magnets and the stripe on your credit card do. In practice, it takes more magnetic flux than most people would expect to alter either. Magnetic fields fall off drastically with distance (inverse cube, not the usual inverse square) so you pretty much have to deliberately try to damage any sort of magnetic media with a handheld magnet.

Magnets were definitely bad for CRTs, because most of them depended on a lightweight metal shadow mask to keep the electron beam from each gun from illuminating the wrong phosphors. If you bring a magnet too close to a shadow-mask CRT, you risk magnetizing the shadow mask (a temporary condition that will eventually be fixed by the normal power-up degaussing cycle), or even warping it, which obviously ruins the tube.

Modern hard disk drives are reasonably tolerant of external magnetic fields. In fact, they contain strong magnets themselves. Again, only a small amount of physical separation is needed to keep those magnets from affecting the media.

Magnets have no effect on normal electronic circuitry, LCDs, or SSDs, unless (again) you go way out of your way to move a very strong one rapidly back and forth at a very close distance. You might be able to induce enough voltage in an unshielded inductor to damage something, if you tried hard enough. I wouldn't be surprised if it's impossible outside of an MRI machine room. Certain inductor cores won't take kindly to being magnetized, so there's some potential for damage there, I guess. Never seen it happen.

I remember doing a science project involving sticking the larger floppies to the fridge with magnets (maybe even neodymium) and freezing others - not a single one reported any bit errors.

Brainiac75 on YouTube did some tests on various electronics (calculator, PDA, PCs, displays) with non-trivial magnets.

A Thinkpad with an SSD seemed to be fine; I'm honestly surprised that it didn't even crash:

https://www.youtube.com/watch?v=pXITrgRkT5k&t=6m&list=PLiAlc...

The magnet is strong enough to directly affect the electrons in the CRT, distorting the raster into interesting shapes:

https://www.youtube.com/watch?v=_yEu2R1gYSs&t=2m20s&list=PLi...

Thanks for the thorough response! This is really interesting stuff. I have a few HDD magnets stuck to my wall and their existence confused me. I would never have guessed that the falloff was that big.

If you want a real upgrade, I swear by the cables that have integrated watt-meters built in.

It's so nice to have fast feedback about how heavily you're using a multi-port charger, to see whether your phone or laptop is charging as fast as you'd expect.

It's a pity that devices don't just report their charging figures. In Linux a lot of laptops have really good power reporting; I could tell exactly how fast my laptop is charging. Phones too know. But devices simply don't deign tell consumers what the status is, what's happening. There may be a fast or regular charge... but it's so much less than the real data. For a lot of devices, the last 20% of charge often goes very slow. Knowing that, seeing that, would be good information, for example.

This times a large physical constant.

I would be pleased with a world where every device I plugged in could broadcast its energy consumption via the low-bandwidth flavor of HomePlug (a powerline networking standard), with a filter at the breaker to stop external data leakage.

It'd be great to know what's eating the most power, how much capacity I'd need to plan for home solar or battery-backup, identify leaks, etc.

Doesn't it make more sense to have that at the power source end (charger) rather than the power sink (device)?

After all, most devices are pretty dumb, and us device designers like it that way. As long as it's optional (meaning I don't have to buy it, because I personally will never use it), go ahead and make the chargers as complicated as you please.

Point!

You'd want some type of aggregation protocol, so that power-distribution devices can send more granular data up the chain, but yeah, it'd make more sense to build this into said devices: outlets, power strips, chargers, and so on.

I too rather want smart chargers, intend to go build some. I was planning on using wifi (or perhaps bluetooth, via Zephyr IoT, but that seems harder right now). HomePlug would have been kind of exotic to weave in.

> Doesn't it make more sense to have that at the power source end (charger) rather than the power sink (device)?

I would prefer having a separate meter, so that I can place it first at the power source, then at the cable end, to know if a malfunctioning device could be the result of a flimsy cable producing a significant voltage drop. This is a very common scenario when using dubious quality cables.

Hmm, aren't all physical constants quite small, even the largest?

You can get smart plugs with energy monitoring.

> cables that have integrated watt-meters built in.

I have never heard of such a thing but I'm interested; any brand you can recommend?

Just look up USB-C cables with power meters on Amazon; there are tons of companies that end up rebranding the same product.

Try reading the submission article ;)

It finishes with:

> Or, if I’m really dreaming, how about 40Gbps for USB 4? Let’s go for broke and make the ultimate cable — give it a built-in power meter while you’re at it.

Links to https://www.theverge.com/2022/1/28/22907150/usb-c-pd-cable-p...

Which, in turn, links to some arbitrary-looking items on Amazon, which I actively distrust for power-delivery products. Hence, asking here to try and find out what brands are actually good so I can go buy them directly. (Likewise, I trust HN commenters more than The Verge anyways, so I figured I'd ask before spending money)

None of them are trustworthy, but so far I've made a habit of buying different brands and they've all worked and worked fine. They're all ruggedly built, all nicely jacketed cables, and all seem to do 5A just fine.

I recently found these too. Very handy! Got some for ~$8 delivered on AliExpress. The ones I got only work with USB-C with PD (won’t fallback to micro usb for example) but I’m in love. It’s so handy to know I’m charging at maximum speed.

I'm still trying to understand why I should care. My work is sedentary so I have plenty of time to charge.

I've found silicone jacketed cables almost perfectly tangle-resistant, and any knots that do form migrate to one end with pulling/jiggling instead of becoming tighter like they do in PVC cables.

At least, that's been the case with the ones I've used, which are the 1 m and 1.5 m power cables from Pine64 intended for their soldering iron. No idea what spec they are, other than that they support the iron's max 60 W and provide at least some data transfer ability.

They have 16 pins, missing the differential RX/TX pairs. So, according to Wikipedia either USB 2.0 or 1.1?

https://pine64.com/product-category/pinecil/

Edit: Just realized I've been using the hook-and-loop strap, so perhaps they haven't had a chance to become really tangled. But that's the sensible alternative to magnets! Packs of them cheap and work on any cable. It also seems like always folding a cable the same way doesn't cause the long-term damage that repeated tight (non over-under) coiling does, since the insulation doesn't get twisted when it's pulled straight.

Doesn't coiling cables while passing increasing levels of power through them (which is exactly what's happening with new USB-C PD specs) start giving off more and more heat?

EDIT: Nope! See the replies.

No. The amount of heat given off is just going to be I^2R, and coiling the cable doesn't increase R.

If you coil it so tightly that the heat can't get out, that could be problematic, but it is not likely to be a problem with this coiling technique.

Coiling is only relevant to magnetic fields. These cables generally have the same amount of current passing in opposite directions through different wires, so net zero.

Ah that makes sense! Having current in opposite directions in the two wires in the cable cancels it out. Thanks for explaining.

I guess the warnings about not running loads of current through coiled cables are more to do with heat dissapation then?

Coiled extension cords are definitely a hazard at sufficiently high power, though.

Coiled AC extension cords.

Possibly a silly thought:

Is there any risk of hitting a “critical mass of consumer magnets” that makes screwing with other technology far more likely?

Like, if every darn product I own tries to solve problems cleverly with magnets, suddenly I’ve got powerful magnets everywhere.

I guess it’s good I don’t have VHS anymore.

Pacemakers have reed switches so a magnet placed over them will turn off heart rate sensing and switch to a fixed rhythm, which iPhone users found out about recently when Apple added magnets to their phone. Other than stuff like that, I doubt it'll be that big of a deal.

Of all the places to put a magnetically sensitive device, that seems the most irresponsible.

Apparently it's the most K.I.S.S. method of being able to check on a device that requires surgery to work on, but yeah, it can lead to nasty surprises.

The average person probably didn't read most of the iPhone 12 marketing page[0] before buying it, especially if they just happened to need an upgrade and walked into the carrier store to get it.

0: https://www.apple.com/iphone-12/key-features/

Seems like a big waste of neodymium for a bit of lazy convenience.

"Big waste for a bit of lazy convenience" sums up the present state of things quite nicely.

I haven't done the math, so it's conceivable to me that self organizing cables have a longer duration, hence, maybe off-setting the "waste" of neodymium by reducing waste of copper/plastic.

I'm biased towards thinking it does not offset, but I'm not sure, I haven't done the math nor read of someone else's

I'm just mad because that phrase you put in quotes sums up how people jump to conclusions before even caring on doing the math, as if decisions shouldn't depend on the outcome of those calculations

Most of visceral complains about plastics comes to mind, if you read from someone that has done some barely competent calculations and investigations, you realize that most of what should be done is to avoid the use of plastics near bodies of water, and only in the cases where the math says it's a good trade-off

So the cable is a device with a microcontroller and we’re just ordering them from Amazon then plugging them into our computers. Cries in infosec. I guess it’s no different than a cable having a hidden microcontroller but still. Maybe I’m too paranoid.

I think every USB-C cable has a micro controller built in. As does every Thunderbolt cable, or Lightning cable. They need their DRM, if nothing else.

How long until someone accidentally breaks their device through electromagnetic induction?

Yes. I imagine solving Maxwell's equations for this geometrical arrangement of neodymium magnets and cable would clarify all too clearly why they have "lackluster USB 2.0 speeds".

Quite a while (see my other post).

But what about corrupting data?

If you're still using devices relying on magnets; it's time for an upgrade.

I mean when you move the cable. The magnet will induce current on the data lines.

Which devices are still susceptible to magnetic fields? besides HDD

I personally quite like the magnetic adapters which turn a USB C charging port into a magsafe-type thing. About £4 from AliExpress.

Even without the magnetic connection, the right angle works much better for me than straight out.

I was looking at those, but are there any that'll do pd?

Mine charges my laptop OK. Pretty sure they just do pass through, so the device negotiates the PD as usual.

I think it's more likely that it wouldn't work for a USB 3/TB dock thing as I imagine the high-frequency signal integrity is trashed by such a thing.

I read that most of these make devices more vulnerable to ESD / wrongly connected pins due to poorly thought-out contacts. Not sure how true that is--are modern devices protected "fully" on every pin?

Once I had a large visible arc to the USB C port of my phone. It was off afterwards and wouldn't start, which was scary, but turned out fine after taking the battery out and putting it back in. Someone know how that could have happened?

I looked into these a while back, the reviews were meh. Is there a brand with good reviews these days?

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