My xLED chest implant

Hey folks! Working on something cool and could use some help. I’ve implanted am xLED onto my chest with a transdermal anchor point above it. I am trying to make an externally mounted 13.56 MHz coil and battery or LC resonance circuit that sits on the anchor and lights up the led. What is the best way to make a custom coil of the right frequency? Custom PBC ? Can I make this by hand ?

It’s pretty swollen due to transdermal so I haven’t been able to test anything. I tried with an induction coil that works with custom coils I’ve made and it didn’t seem to work with xLED . Wondering if anyone has thoughts ?


I have thoughts. You’re going to want to make a short cylindrical coil shaped like the one inside the implants (similar to the custom one made by Tom Harkness for the proxmark), and you’re going to need to orient the long axis of that coil in parallel with the long axis of the implant to get good coupling from that distance.

If you want to make this circuit battery powered, you’re going to need to convert the DC from the battery to an AC waveform oscillating at the resonant frequency of the LC tank circuit in the xLED (13.56MHz). I recommend you check out a circuit like the Hartley Oscillator to perform that conversion. If you can get that circuit working on a breadboard with the xLED (or a circuit that simulates the xLED) then you could go about miniaturizing it for a custom PCB.

I train people how to build circuits and design PCBs, so if you decide to go that route ping me and I’ll send some resources your way.




Killin’ it

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Watching this thread closely. Transdermals scare the piss outta me but this would be worth it.

this is cool.
i’m planning to do something similar for my xLED: werable board to power the implant and modulate the blink based on live data.

Also: transdermals are moody beasts. Be gentle with it, as they get angry very fast for little to no reason :slight_smile:

(Small keloid scar from something stupid I did 15 years ago, pay no mind!)

It’s doing pretty well day 5. Bruising but actually feels pretty good generally. No pain. No bleeding .


@Satur9 assuming the coil will be laying on the skin overtop with the xLED under and, I presume, in the center, how do you think a torrid coil would work for this?




I do not think a toroidal inductor would be ideal for this type of situation. The magnetic flux lines are most densely packed in the center of the hole running parallel with the axis of symmetry:

If it were resting on top of the xLED, the brunt of the field would be running perpendicular to the coil in the xLED and no power would be able to transfer. A toroid would make a cool necklace, though.

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So! Update!

I haven’t been able to get my led to light up. I tried with my pixel 2 xl and an rc5222 reader. Nothing. Amal sent me a second xLED to try, still nothing when it’s implanted.

I am wondering if it’s the base of the transdermal? My phone ? My reader?

Any ideas ?

I’m keen to help with this as I have a similar idea for something and and currently working on 13.56mhz coils for another DT project. Heck, I think we can do this with mostly of the shelf stuff (nfc coil from a phone etc.) We could even make a little circuit that allows you to control the light on / off timings.

I may just build a test circuit for this tonight and post some details here.


Well these are all perfectly valid points, I’m sure we can come up with something that is more aesthetically pleasing than a cylinder design :wink:

Nice suggestion with the The Hartley Oscillator circuit - saved me some research haha!

It’s a tiny antenna and it’s somehow underpowered most of the time, because, not having a chip inside, the remote active counterpart powers it with intermittent polling probes, so basically good coupling can be tricky to achieve.

I can power mine with my Mate 20, but I’m having trouble with my rc5222 (which works perfectly fine with other NFC cards).
I guess the transdermal base is titanium and it looks to be >1inch from the xLed, so I would imagine it’s not causing the problem.

By the way I’m also trying to wrap my head around a good way to make myself a wearable HF coil, so I’m super interested in the development of this topic :slight_smile:

I have a ton of ideas for the wearable part (I teach wearable tech /cybernetics at a university in Canada) so def less concerned about that later. I am in the process of fabricating an enclosure that fits around my transdermal. But I’d like to see it light up first. Now I guess I’ve got two xLEDs in there in the assumption one was busted. Going to wait for the seeing to subside and try this readeereader:

This is the reader board @Leeborg had and she had similar issues… is there a low power scanning mode or “field detect” mode for this board that can be disabled? What exactly was your trouble using it with the xLED? I have a hunch this is the issue and she has two good xLED in her :slight_smile:

Take the case apart and remove the PCB and antenna so you can see exactly where the antenna traces sit… and try an RFID Diag card on it to ensure it has a proper duty cycle… or better yet use an xLED that isn’t inside you to test it with to ensure it’s all going to work as expected.

My experience was simply that the xLED would not light up, regardless my effort to find a good placement for the reader.
I agree: it would be nicw to investigate and figure out if the board can be told to consostently send full power; I’m goibg to tinker with it a little bit more as soon as I have some time.

Oh!! I do hope this is the issue. I am currently just fighting with the new reader to get it in a read mode. Stand by for an update.

Maybe we can make a list of readers and phones that work and don’t work ? It hasn’t been a stellar experience but absolutely nobody’s fault.

sigh using the ACS1252 and unable to download the software on my Mac to change modes… Therefor still unable to test my xLED.

What is university offers this class!?!


My Galaxy 8, Galaxy note 10 plus, and iPhone 11 pro max all can light up my xLED.

Hope that helps with the list

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