RFID locations

edited July 2015 in RFID/NFC
Hi I was looking to see afrom some some people's experiences on RFID locations. First off I wanna say I'm in construction so I'm always using my hands. I was hoping to place the new RFID chip from cyberise.me that is smaller and place it in my right hand on the left side instead of the common between thumb and index finger. My reasoning is twofold one is because I'm always grabbing stuff and using a hammer the other is easy of use on a reader.

My other question is in regards to a good second location higher up for Accra through automated doors and sensors for lights that is all the second chip would be used for.


  • Meanderpaul  Can you explain exactly where you are thinking of implanting the chip?
    I don't know of anyone with RFIDs in other parts of the hand, but the chip in question is pretty small, so putting it on the outer edge of the hand would probably be ok, a know a couple of people have magnets in that location.

    as for other locations, I know of people with chips in the thigh, forearm and shoulder blades. In general the chips are pretty small and strong, as long as they are not placed too near bone, they seems to fine in any area.
  • Look at the top of your right hand, pinky finger first knuckle (furthest from tip), the section between that knuckle and the wrist.

    I was thinking near the top of the trapezius (did a Google search) I want it as high up as I can place it so I don't need to make the readers too strong in door jams and such (I'm 6'1" chip will be around 5' up)
  • I found this image, if I understand you correctly, you intend to implant it parallel to the metacarpal, right? I think that should be fine, but you should probably wait for @cassox to confirm that.

    My only concern is blunt force trauma, such as in martial arts.

  • That is correct. My worry was it moving towards my bone and me being me braking it.
  • @Amal and I tested the crushing resistance of some rfids. The basic take home was that if you have managed to break the rfid inside your hand, that area has probably been reduced to a pulp and the breaking of the rfid is really the least of your worries.
  • That is very good to know lol. Have you noticed anything in regards to orientation for best readings and depth of implants for distance of the readers?
  • I posted in another thread about asking about location, but since this one if up its a way better place. From what I learned in the other thread, I'm pretty sure that I am going to put a chip on my right hand middle finger middle joint left side, so that I can unlock my phone. Thank you @glims for talking about strength it is very helpful.

    @Meanderpaul NFC and RFID dont really care much about orientation, especially the implanted ones since they are cylindrical. and a normal chip ran be read from < 20 cm (according to spec but you never get quite that far) so you have no need to worry about distance much at all.
  • So my main problem will just be in the building of a reader to do what I need which is actually a good thing. Do you foresee any problems with it moving to or being to close to the bone in my hand near the metacarpals?
  • Would there be any sort of worry with implanting a second one in my trapezius like the fact it's not fatty like my hand?
  • I would say the closer to the bone to better, if you have it up against something straight and hard (like a bone) it will be even harder to damage. I would say try to avoid implanting to the bone, but if it moved there then you will be fine.

    as long as your reader doesnt get confused then implanting multiple should be fine. since your trapezius and hand are not going to be close to eachother while reading you should be fine. 
  • I was planning on having the one at trapezius being a different format to not interact with a different reader. My hand one would be (mostly/hopefully) HID and the other a different one depending how I build the unit.

    Everything I read said not to put it near the bone. Is the risk of slashing between bone and a hard object that minimal with it? I know @glims said it would take enough to really mess my hand up. I guess I'm cautious with the one in my hand. I have really no worries with my other spot aside from lacking fattyness in it.
  • If you calculate the breaking stress of the glass tubing based on schotts published modulus data, it's not quite as impressive as its being made to seem. They are strong enough that one doesn't need to worry much about breaking, with two exceptions: a quick impact or if placed too near bone. The value if one places a tube on a hard surface and applies pressure to the wall of the cylinder according to Schotts reported youngs modulus of 64 MPa  is between 8 and 30lbs of pressure. When placed between fingers though, the cylinders moves and have significant cushion from the tissue. A quick blow however could transfer enough energy to break the tubing. Something like a piece of rebar is a worst case scenario. I've never actually heard of anyone having one break despite all the free runners and martial arts folks involved.

    Back of the hand is not an advisable location though because it's one of the most likely places to be struck, and because of the proximity to bone. The bone can function like that "flat hard surface." Have you considered the forearm instead?

    Rule of thumb is to avoid to joints and surface bones as able. RFIDs are impressively strong but it's still glass.

  • I haven't considered the forearm mainly due to easy of use if I connect a reader to my truck and house door to unlock them and at some point start my truck. My main concern would be a hammer impact but it would also be towards my palm more then the top of my hand.
  • Valid. Hey, if the glass breaks it's not the end of the world. You'd definitely want to make a small incision and get out as the chip and as much glass as you could. A couple little shards though left under the skin aren't a big deal and would most likely just work their way out. Dude, I'm sure you've had splinters that were larger and more invasive to remove if you're a framer.

  • Oh ya I have most of them were steel shards from metal studding. Well all that's left now is to get the chip! I'll be doing that part next week ( no bills due). I still need to assemble a reader/writer but that's just going to be a fun thing to do.
  • That's a good point about the potential issue due to quick impact. The device we used incrementally increased pressure till we just gave up cause everything got pulped. It kinda hit a plateau. The tools for testing youngs modulus don't do strikes.

    I figure there is a good way to test this tho. I need to go talk to the physics machine shop and see what they have.
  • Talking from my own experience, the place between thumb and index finger (the metacarpal thing) is pretty good. The tissue is soft and forces applied to the tag will simply move the tissue instead of damaging the tag itself. To damage the tag you'd have to hit something so hard and forceful, the tag will probably your least concern anyway. I never feel the tag nor does it hinder me in any way. even handling ropes or hitting stuff with the back of my hand is no problem. The only time i do feel it is when something/someone is rubbing the Tag against the nearby bones. Rubbing hard stuff on bones is not a nice feeling.
    So my recommendation is: stay away from the bones. It's not comfy and increases the chances to hit your tag with two hard objects at once. Placing it just under the skin makes removing easier, and reduces the distance to the base station antenna (which can be of advantage)
  • The correct device to do this kind of test is an oscillatory shear tester or else you need to apply all kinds of formulas. Testing something is more than just sticking it in a machine and seeing what the read out says. Like the Geiger counter incident.. if you don't know what you're doing the results are misleading, false, and people can be harmed.
  • So sticking it in an analog and hitting it with a hammer is out of the question lol.

    On a different not I want to just be sure the fatty part near the metacarpal is an OK spot? Safety wise
  • I currently have two NFC (xNT) tags.

    The first is between my shoulder blades, (one inch to the left of the spine), and the second is on my left forearm (pic from about a week after implantation below).

    The forearm chip is placed just beside the leftmost tendon placed just below the bony protrusion of the radius.

    I find the placement is a great location as it allow me to easily unlock my phone by tapping it to the spot and share contact info with people I meet. The thin skin on the wrist also aids in ease of reading and writing. The chip is not visible in any way as it is nestled nicely into the depression in the arm. I am able to make it slightly visible by pulling the skin that holds it up and over the tendons. 

    The shoulder blade chip works great for my purposes though the skin thickness in the area makes it slightly more difficult to read and write to.

    Over all, I am extremely happy with my chips. I plan to get a 125kHz chip near my right shoulder blade for ID, an ISO15693 (Dangerous Things: xIC) NFC chip about 3 inches below the existing NFC chip in my wrist, a temperature sensor chip near my left armpit, and another 125kHz chip in my right hand (between thumb and index fingers) for unlocking my car doors.

  • I agree. This is why I'm talking with the physics guys. Not my tool. Don't know how to use it.
    OST is pretty vague. All I can get is a tool for testing dynamic mechanical analysis, but even so, this is more of a polymer type of thing. I have no idea how to use this on a solid.
  • Look up a Linear Skin Rheometer, the OST used in physiology and medical settings. These are used to determine the mechanical characteristics of tissues.
  • @Meanderpaul to answer the question about the fatty part near the metacarpals. No problems known from that area so far (see the xray on the left). I know multiple people with RFID chips in that location.
  • @thomasegi The location I was using was on the little finger side of the hand. I assume it would have the same effect as I between maybe a little better I would assume because nothing would be pushing on that spot really ever.

    I'm entertained that I managed to get a question about sudden impacts going with the implant and its durability. @glims please let me know what you find out not just because I had question but now I'm genuinely curious on how the test will go and works.
  • So, one of the things that we were curious about with the DMA tool is that it's really more of a polymer thing, yknow. A linear skin rheometer is about elasticity of the skin, which is unfortunately, kinda the same thing.

    Actually, after googling it, it's totally the same thing, but for skin instead of hydrogels. We already did this. Like, the tool is identical.

    This means we would probably get the same results. We need something that measures accute impact strain on solids. Preferably solids inside a squishy substrate (like a hand). I still don't know what that is. 

    Has anyone ever had one of these rfids break? It's a iffy metric, but if there are no reported cases of rfids breaking in animals or people, that's a solid background of evidence. A good step one.

    Putting something in the smallest finger of your hand sounds like a bad idea. You may think that nothing ever interacts with that spot, but often we forget how normalized we are to using our fingers. Soft and innocuous is always better than small and boney.
  • My school has some sort of shear impact tester in the mech labs, it's a pendulum arm with a wedge on it that impacts a metal piece and shears it. You just raise the arm higher until it cleaves the metal. Sounds kind of like what you're looking for.
  • @glims it's not the tip it's in the meat of the palm probably a more accurate location would be hamate. Please excuse my poor biology references as I haven't been in a bio class in 6 years.

    Base of little finger in the fatty section of the hand on that side.

    I'm actually now thinking if you have access to a pig....implant the rfid and have the hammer/tool/ whatever swing at a preset force into the location of said implant. Gradually increase the force till you have the breaking point. I know it's not the most scientific thing out there but hey it may enlighten and give some actual numbers.
  • Actually that's pretty much what was done. Except that he used a device that puts pressure in inreasing increments. The problem is that the rfid will move in the tissue. If you want to determine this, you'd have to use the ost on the specific tissue and an engineering version on the tags and add the values. There are methods to calculate force that can take into account both mass and velocity I believe. Electric field, if you have access to that device it would be cool to get a value.
    I think that the testing glims did are totally valid for implant in the thumb webbing. The tissue will be destroyed before the tag would. This all changes with location though. If smashed between the striking surface and a bone its a different story. Also... rfids are cheap and easy to implant so it's not a big risk. If one breaks than we learn something.
  • I can definitely get access when I'm back at school. Remind me in a month and a bit.
  • @cassox is there a certain depth and angle to implant the chip at to keep it from coming back out?
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