flexNExT interference on xNT

Hi everyone,
As already mentioned on the forum, a flexNExt on the back of the hand along with a xNT between index and thumb will probably interfere.
My question is: what would this interference cause? Both wouldn’t work? Maybe trying to read in a different position would help to prevent the issue?

I have biochips on both hands, but really want to install a flexNExT on the back of the hand


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I don’t think this would be you issue, if any…
You would probably read one OR the other
Read one THEN the other depending on what is reading it.
I think it maybe learning how to approach the reader to get the “correct” read.

Worse case scenario, the FlexNExT is the better read range with the same functionality as the xNT so if you have an issue, “just” remove and / or relocate the xNT

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This is a total guess based on some logical thinking:

I wouldn’t worry about interference too much given how finicky/pedantic you have to be to get a read on the xNT already. If you have the xNT in the usual place (between thumb and index) and no other implants on that hand, reading the flexNExT closer to the pinky should avoid any interference.

Depending on your reader situation, you may get some anti-collision errors making you aware that two chips are being read/detected by the reader.

Technically speaking they would both be able to be read and accessed if both were in the field… this is why ISO14443 defined anti-collision features… so readers could read multiple tagged things in the field at any given time.

The problem comes from the fact that basically nobody outside of inventory control software programmers bother with that at all… they just grab the first tag ID they see and select it (select is an ISO14443 standard command)… once the reader selects a specific tag ID, the rest shut up (go into HALT state)… and this is why we can’t have nice things. This is why you can’t have multiple cards in your wallet and present them all to a transit reader or a hotel elevator or an access control reader… because programmers are lazy, and they don’t know how to do a simple goddamn for/next loop to save their lives to cycle through the cards in the field to find what they are looking for… nope… forget that noise… just select the first card and if it’s not the card we’re looking for, honk a big donkey error beep and fold your arms because we ain’t doing jack crap until you take all those damn cards the hell out of my field and try again bozo.

As you can tell, I hate this. Why bother coming up with an awesome anti-collision mechanism if nobody bothers to use it. Slap them all. Hard.


I doubt this would be a problem, for two reasons:

  • Case #1 - Activating the glass implant between the thumb and index when reading the flexNExT on the back of the hand: with my own NFC implant, I really need to be close to the reader for the implant to reply. Best case scenario is with the good old ACR122U, with which I get half an inch of read range if I’m lucky, on a full moon. There’s no way it would trigger if I put the reader anywhere on the back of my hand to read a flexNExT there.

  • Case #2 - Activating the flexNExT when reading the glass implant: that’s more of a possibility, because the flexNExT has a greater range. But it’s not very likely because when you present your hand to the reader to read the glass implant, the flexNExT would end up at a steep angle, possibly almost vertical to the reader - meaning it won’t be oriented properly in the field.

I think the flexNExT would have to be implanted very close to the thenar muscle group and you’d have to make a “flat” hand and stick the reader kind of in the middle to activate both implants at the same time. That’s not very likely unless you do it on purpose.

But I’ll tell you what: if you want to be extra sure, if you insist, I can stick one of my bullseyes on the back of my hand and give it a shot tomorrow.

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What Rosco said! I had a play with my flexNExT and it isn’t as big of an issue as i thought it might be. It seems to respond at fairly steep angles, but getting up closer to 90º and it definitely doesn’t respond. It’s powerful, but directional.

It would definitely be a little harder to use the glass tag, since you’d need to pull your thumb more ‘in’ to make sure it was a right angle to the flex, but as long as you do that, selecting a tag to scan should be pretty simple for you.

Great discussion!
Doesn’t look like a problem. Definitely want to see Rosco test!
Anyway, I’ll order the flexNExT and make sure to post some reading tests
Thanks everyone!

as @Compgeek predicted

FlexMT ( circles on back of my hand )
NExT (line in position zero)

Tested them and zero issues. Effectively scanning 90⁰ :triangular_ruler: to each other eliminates any problems and was infact an easy and repeatable process.

I took some video if you REALLY need to see it.


Just ordered a flexNExT, soon I’ll have some footage!
Thanks once again everyone for the discussion

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