Magnetic Fingertip sensors
It seems that some crazy group of people have been opening their fingers (OUCH!) and embedding magnets under their skin. This allows them to sense metal running under walls, detect motor movements and AC current and many other things.
However, cutting open skin sounds dodgy to me, and as well as being unnecessarily painful, has resulted in bits of magnet breaking off and embedding themselves further into the finger, infection, and loss of fingertip sensitivity. That’s just not good!
Now, on Mark Ivey’s blog, he recounted finding a magnet and gluing it to his fingertips with wood glue (and considered super glue!). Which while being much less painful still sounds a bit too much.
So my own suggestion is why not embed them into a set of gloves? The cheapest way would be to buy a pair of Marigolds (kitchen rubber gloves) that fit you, and then glue the magnet to the inside of these. The disadvantage is that the pull may not be quite as detectable, and also that the gloves will make your hands more clumsy.
So my more expensive, and interesting solution, is to make latex finger sheaths, and put bits of Neodymium magnet into them.