A week or two. Turn on a microwave--that should do it. Or go into a bookstore--you'll feel the scanners at the door.
I live in NYC, where there are all kinds of things hidden behind walls and under the sidewalk. Maybe you're just in an area deficient in weirdness?
Ayup. My superpower might not be anything to write home about, but it's what I've got!
See other posts I've made here. I went to a body modification guy who does these, it was a quick procedure, basically healed in a week. Once the swelling went down, I was able to feel more stuff. The things I feel most often are electric ranges, microwaves, security scanners at stores, and wall warts.
Because it was there:Mountains::Because it was awesome:Subdermal mangets
I like having senses other people don't. It doesn't give me any practical advantage, but it's neat.
Speaking as a guy with magnets in his fingertips, you're wrong. They're nowhere near strong enough to cause trouble.
Only if the fields are changing. RTFMAXWELLEQUATIONS.
Subdermal magnets are pretty weak compared to the magnets you'd find in, e.g., a hard disk head. Speaking from experience, they certainly aren't strong to wipe a credit card, so I double they'd be a threat to any practical device.
The magnets that they use are coated pretty well. Mine are actually flat little magnets that are used in magnetic stirrers in chemistry labs. They're made to be as inert as possible.
In the first generation, the guy who did them coated them with silicone that would rub off. It would cause the skin around the magnet to blacken once that happened. Once I found out that they fixed that problem, I jumped on it.
Of course, if I ever need an MRI, I'll need them taken out.
It's pretty sweet. I've got one in my right thumb and index finger. I feel a buzz whenever there's a strong enough alternating field nearby, and a tug whenever I pass my hand near strong static magnets. I'll be walking down the street and feel sensors to detect the presence of cars, and I can feel the brakes in subway cars. Nothing particularly practical, but I figure I may get a couple of seconds warning before the shockwave if I ever feel an EMP.
In terms of strength, I can basically pick up staples. Anything heavier falls off. Other magnets I can drag around on the table pretty easily, though it's uncomfortable to have them actually contact my fingers.
In particular, it's worth noting that the entire case file for all issued patents is publicly available (http://portal.uspto.gov/external/portal/pair). For this patent, you can see exactly what the Examiner thought made the patent allowable over the prior art.
Go to the Public PAIR website, put in the patent number, and then click on the "Image File Wrapper" tab. The document you're looking for is the Notice of Allowance. In this particular case, this is what the Examiner thought was allowable over the prior art:
"Regarding independent claims 32 and 43 the prior art of record fails to disclose or suggest the combination of claimed provisions of:
a bookmark element; wherein the bookmark element includes an identifier attribute that associates a start bookmark with an end bookmark element wherein two bookmark elements are used in book marking a portion of the document; wherein each of the two bookmark elements include an opening tag and an ending tag;
a document properties element;
a text element that contains text of the document; wherein all of the text of the document is stored within text elements such that only the text of the document is contained between start text tags and end text tags; wherein there are no intervening tags between each of the start text tags and each of the corresponding end text tags and wherein each of the start text tags do not include formatting information for the text between each of the start text tags and the end text tags;
a text run element that includes the formatting information for the text within text elements;"
A quick glance tells me the patent was rejected three times, so the enterprising individual can easily read the rejections and Microsoft's responses. If you think you can find some references that cover all of those elements, and you've got some cash handy, you can file what's called an "Ex Parte Reexamination" that will put the patent back in question.
No skis take rocks like rental skis!