Location / depth concerns


I had my chip implanted yesterday, and I haven’t been able to use it or get it detected by any of my readers yet.

I’m concerned because I can’t really see it under my skin and it’s kind of hard to feel right now.

Am I just being impatient? I’m concerned that it’s too deep, is there anything I can do to determine this or anyway to fix it easily without removing it :slight_smile:

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I’m pretty sure I read on here, it may be hard to read (or feel) right after install… Also may depend on the reader. Some readers work better than others with these small tags. What tag did you get and what readers did you try?

I’m a noob, but the general consensus of stuff I read is be patient, and don’t play with it. Let it settle.

If you haven’t, read the FAQ too… X-Series Implantable Transponder FAQ

@turbo2ltr is correct… there may be inflammation that is causing just a bit too much tissue between the reader and implant to get a good read. This is common.

Also, try different orientations. Check our xLED product page for a video that explains this.

Finally, what chip did you get and which readers are you having issue with?


Thanks for the responses! I did end up getting a successful read just now. It’s an xEM chip and I’m using a proxmark3.

Read the post about the antenna not being the greatest and started moving the lf antenna paddle around and found where it would read best with the lf search u command. Ended up finding a location that it worked in.

Thanks again!

@bumjubeo, I’m having the same issue with the proxmark3 easy…how did you end up positioning your hand?

I positioned my hand flat on the ground, and placed the antenna’s centre hole closer to my thumb.

Thanks! I’ll try that tonight.

I’ve had great success with a Pm3 and a cylindrical antenna that I hacked together. The antenna itself I actually got from the DangerousThings xEM access controller kit:

After locking my xEM with the infamous BlueFreakingCloner (before knowing the issues). This coil was my saviour. It gets clean reads an inch away from my skin when orientated as shown in the picture below:


Fantastic! This is the same approach I took as well (end of this post)… but since I don’t have a source for these coils anymore, I’m looking for a sustainable design.


How about http://www.coilcraft.com? Currently looking into getting some coils made to test.


Can you tell us what you did to remove the coil from the xEM access kit and put it on the Proxmark? I have a proxmark 3 easy and had no success putting the antenna from the access kit on it.

The bottom part of this post shows the end result at least. Basically you desolder the antenna from the access controller and solder on a USB port. I actually have to do this myself again since I shipped my one antenna to a customer and they went radio silent… dang… have to make a new one. I will be sure to take some photos.


Hmm. The Proxmark 3 Easy doesn’t use USB plugs for the antenna. It seems that the screws holding the circuitboards together are also used as data conduits (wires).

ah right… the easy does not use the “original” antenna connectors. i have ordered an easy and it should arrive tomorrow so i’ll take a look at it and see what we can do.


Resurrecting an old thread. I am in the same boat as the OP. My access controller arrived today, and i happen to have a PM3 easy that doesn’t quite couple well enough with my NExT implant. I’m handy with a soldering iron & electronics, but EM wave propagation is a little out of my wheelhouse. I could connect the cylindrical antenna to the PM3E, but has any other testing been done to determine if the above instances are flukes? Have there been any other attempts to do the same but failed (or caused damage from reflected waves)?
Thanks all!

It’s not waves at all actually…

Be sure you are placing your NExT perpendicular across the LF antenna coil, like this…

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I actually followed through and did connect the access controller antenna to the Proxmark 3 Easy, with either polarity, but with no success.
Using the field detector LED to find the best orientation, the LED lit weaker than it did with the original PM3E antenna.
Using the original antenna, I could get a rare single-pulse read on the implant with the LF HID FSKDEMOD command. Using the Access Controller antenna, I got nothing. It almost seems if the PM3E just doesn’t have the output to work with this antenna. Which might be correct, as the read range of the Easy is less than any of the ‘better’ PM3 versions.

I’ll either try to find someone locally that owns the full-fledged PM3 and try this antenna, or wait until TomHarkness can develop something suited for the PM3E.

The problem you are going to have here is that passive systems use L/C tank circuits … which are basically a matched capacitance (from capacitors) and inductance (from the coil antenna) to resonate at a specific frequency. The only way an antenna swap-out would work would be if the antenna you were replacing had the same inductance as the xEM Access Controller antenna, which would be kind of a miracle. Further complicating things, the tuning capacitors on the proxmark3 board change values all the time. As the antenna coils used change, often the manufacturer will change the capacitors. In short, without either a lot of trial and error or some foreknowledge of the capacitors used on your particular PM3 board (and some math), matching the xEM Access Controller antenna coil to the PM3 will be nearly impossible.

The good news is, @TomHarkness has made some serious headway with antenna coils for the PM3 rdv4 and they should be hitting the market soon.


Hi @amal and @TomHarkness,

My Proxmark3 RDV4 is currently waiting for Monday at the Post Office and my xEM is in my hand. Unfortunately, the new xEM-specific antennas for the RDV4 haven’t come out yet (soon I hope :slight_smile:). Until that time I’ll be fiddling with the antenna from my xEM Access Controller. I’m handy with soldering and hacking things together, and it seems like getting the antenna hooked up to a USB cable and attached to the Original Proxmark3 wasn’t too hard. Interfacing with the RDV4’s what look like snap-connectors for antennas might be a challenge, but without the board in my hands I can’t be sure. I intend to try, though, until I can pre-order an official antenna from y’all (they look amazing).

Can either or both of you provide more details on how you made these antennas out of the Access Controller?

  1. Are there wires that need to connect in specific ways?
  2. Was there anything you needed to do in the Proxmark3 software to set up the new antenna?
  3. Do you have experience attaching non-stock components on to the RDV4’s connectors?

I’d love any and all info y’all have on the subject, as it seems a pretty easy way to get scanning xEMs.

Thanks very much,

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It’s pretty straightforward… you just connect the two wires from the antenna coil to the correct pins on the USB port… however, the problem you will undoubtedly run into is tuning. This is not normal RF stuff where you just take a length of wire of the correct length for the frequency involved and attach it… this is a resonant L/C circuit, and when you are fiddling with the antenna part, you are just fiddling with the L part of the L/C circuit.

Basically the frequency of a resonant circuit is determined by the combination of L (inductance) and C (capacitance)… and these work together to produce a resonance at a specific frequency. To make it simple, let’s say you have an L/C circuit where L is 10 and C is 10 and the frequency is 125kHz… and now you come along with a new antenna that has an L value of 15… well that’s going to drop the frequency down to like 100kHz… so to adjust things, you need to drop your C value to 5 to get you back to 125kHz… these are just bullshit numbers, but the example is correct. If you bring in an antenna that has a higher inductance you need to drop your capacitance to hit that frequency target, and vice versa… if your antenna is lower inductance you need more capacitance to maintain the target frequency.

The problem is, you can’t easily change the capacitance of the proxmark3 because it would involve removing and replacing SMT caps on the board… not fun. However, there is one possibility here… and that would be if your new antenna was lower inductance, then you could add parallel capacitance to the new antenna to make your adjustments.

So you might be wondering why some people have been able to just use an xEM Access Controller antenna with their proxmark3 without much fuss, and others are having a hard time… well that has to do with a few things… one being the fact that the proxmark3 is open source, so you are going to get a load of different designs and models and even massive parts changes and terrible tolerance values within a single part SKU… so even if you buy a “proxmark3 wingding edition” there is little chance that there will be uniformity for that product line from one batch to the next… whole cap values could change (as would the antenna inductance values) and the caps they use might have huge tolerances of like 10% which would swing the target frequency quite a bit, especially if they also had shit tolerance on their inductors… you might end up with an L/C circuit “antenna” that is 20% off target!

So, with that out of the way, to answer your specific questions;

  1. yeah… the two wires from the access controller antenna must be connected to the correct pins on the USB jack… there are 4 pins in the jack and 2 are used for HF and 2 are used for LF and I really don’t remember which, but you can test with a simple meter and a working LF antenna… the actual two wires themselves don’t matter… this is not DC and there is no polarity.

  2. nope, just make sure you use the hw tune command to check your antenna quality.

  3. not me.