Hacker News Reader

Comment by mappu | Hacker News Reader

Similar: there are lots of stories of implanting magnets under the fingertips, to 'feel' magnetic fields.

I have one. Ring finger of the left hand. It's mostly useful for rapidly-changing magnetic fields and strong static fields, so I can feel things like:

- the transformer in my laptop charger

- the electric motors in laptop fans and my hair clippers

- the closure magnets on my laptop

- the magnet in Arc mice that holds the dongle on

- the cyclotron in microwave ovens

Why'd you get it? Do you enjoy it? Is it interesting to you still? Are there any risks?

I got it because it seemed like it'd be an interesting experience, and it has been. It's still interesting, but not as much as it was, and I've been beginning to think about removing it; if it ever becomes a problem for any reason, I wouldn't hesitate to do so.

It's not a hugely risky thing. My biggest concern is/was the bioproofing on the magnet becoming damaged.

What do they say at airport security with magnetic metal under your fingertips?

I haven't been through airport security yet, haha.

And lots of horror stories about trying to get them back out when they shatter or start dissolving.

I'd (unseriously) love to do that but it must wipe every credit card, usb key and hard drive you touch...

I actually have one of those (ring finger of my left hand), and I have had zero problems with magstripe cards and hard drives. Also, USB keys aren't really sensitive to magnets.

What happens if you need an MRI?

It quickly comes out and sticks to the MRI machine.

It might come out, but then go back in and out a few times before sticking. Survival would be path-dependent.

Worst case, you tell a doctor beforehand, and they remove it with a swipe or two of a scalpel. These things are usually put in by a professional body piercer with a scalpel and no anesthetic; it's not like they're deep in the flesh or anchored to anything.

Some FLASH technologies- the ones that use tunneling diodes - are sensitive to magnetic fields when operating.

Obviously to larger ones if they are used in USB key format, since the key can go through all kind of magnetic fields while in your desktop, pockets or handbag.

I think this mainly affects writing.

True story - I was working on an embedded project. I measured the temperature of the device using a pocket IR thermometer. I noted that it was a bit warm, so a small electric desk fan ( the kind with the square flat pancake induction motor ) was pointed at it - fairly closely.

I ran a FLASH write test and it stopped working altogether. We unplugged that fan to set up an oscilloscope and presto! it worked again.

Have you ever taken a hard drive apart? The have a big, strong, magnet very close to the platters.

It's unlikely the magnet in a finger would do anything to a hard drive.

USB keys have never been sensitive to magnets, and platter drives are heavily shielded to keep the magnet inside from screwing with stuff on the outside. Credit cards are vulnerable in theory, but I've accidentally carried a wad of Buckyball neodymium magnets in my pocket next to my wallet for several hours with no ill effects; briefly touching the card with a tiny finger magnet is unlikely to do much.

Faraday gloves, to mask your superpowers?

Wouldn't they get very hot in the presence of a strong, rapidly varying magnetic field?

Would they? And even if so -- what does it matter? How many incredibly strong rapidly varying magnetic fields do you come across in your daily life?

Reply on news.ycombinator.com