One of the first electrical tricks I was shown on the farm (on an Allis-Chalmers 7080 tractor) was how to find a shorted wire, by putting a heavy jumper where the fuse went, and then quickly looking for the smoking wire.
I once found a crushed and rolled up .223 casing shoved into a fuse bay of my grandfatherâs kubota. I chose not to question it, especially since there were extra fuses in the cab.
Visiting friends who lost their apartmentâs gym card key. $100 to replace it. What is it? A goddamn HID Prox card. Hooking them up with some T5577s. Never again. Who in their right mind charges $100 for a HID Prox card??
Well now, seems like youâre stumbled across the reason the whole access control industry sucks ass. Itâs considered a revenue stream. Itâs why everyone from the manufacturers to the operators leverage the security features of RFID chips not to improve security but lock you in and ensure you pay a premium for cheap materials.
Not much at all. Is the current that creates the field at density. The huge amount of current needed to generate a strong field itself isnât going to math out.
Basically youâd need to build a huge electromagnet to make the implant into an effective electromagnet.. which seems silly
Iâve wondered about implanting electromagnets as well, along with a wearable power host, for sensing data supplied by the host device. Iâm not sure if my thoughts pertain to what you have in mind.
@AZ_F has the Loadstone PICO to actuate implanted sensing magnets with an external device. I think that using a wearable electro-magnet to communicate to in implanted magnet would be interesting.
What youâre describing is, in principle, like implanting a Qi powered earbud? Put both the electromagnet and the magnet inside the body so an external wearable coil can excite contraction and/or expansion between the implanted coil and magnet, creating an implanted drum that beats to the wearables electric signal. I wasnât thinking so much of using NFC power specifically, so much as maybe affecting a magnet implant by using transformer made from one coil in another implant and the other coil in a wearable, driven with whatever sort of power you need to make something happen. Same principle though.
Why implant a second coil instead of just actuating the magnetic implant with one coil in the wearable like the PICO? I donât know, but I think itâs worth considering if maybe the activity between the two implants in close proximity under the skin would be easier to feel than the motion of one implant moved just by the wearable through the skin barrier. Maybe the implanted coil would act like a sort of repeater in order to better interact with the magnet? Also, it may be easier to feel the relative motion/pinching of two small hard sharp-ish bodies in close proximity within the soft tissue rather than just one thatâs freely floating in elastic skin at some distance under a wearable thatâs probably distributing its larger mass over a wider surface of the external skin.
However, due to the plasticity of the body, I expect that if it were two separate implants we would see them drift as a result of the magnetic forces between them. Unless we have reason to believe that regular usage would pull the implant pair into an ideal relative position, itâs reasonable to suspect that theyâd push one another into a sub-optimal position, at least by random chance. Worse, would they actively tend towards a position of equilibrium in which their effectiveness is minimised? Thereâs also a risk the implant pair might âwalkâ through the body. But if they were combined into one device, that would mean mechanical parts that could wear out, clog up with flesh, pinch nerves, or fail in other ways.
If these are real problems, then Iâm drawn to the idea of two separate free-floating implants and trying to find a way of arranging the average electromagnetic fields such as to control their drift to keep them in an ideal position. Iâve no idea if thatâs possible, or if any of my thoughts would constitute a viable design, but those are my thoughts.
I wasnât thinking anything that fancy, I was just thinking of a non-visual indicator for a tag to start
For instance, if you got an xElectroMagnet (xEM for short ) in p0 and a sensing magnet in your first fingertip, you could get a simple magnet equivalent of a blinky.
Itâs probably better to make a coil with two exposed terminals that stimulate the tissue around it than trying to get energy out of thin air to move a magnet.
Electrolysis might be a concern however. Although there wouldnât be any DC because of the nature of a coil. And sealing the encapsulation around the exposed terminals could require some work.
Is this for sensing magnetic fields with more sensitivity than a magnet, or is it for detecting NFC specific fields and feeling the duty cycle?