That makes a hell lot of sense.
I’m have to wonder why we haven’t heard of many flexMT failures as well then… if this is the case though, it might be hard to stop the LEDs dying 
Not the same construction: the flexNExT was two concentric disks, one really stiff and one totally floppy, with the nails positioned radially across the boundary between the two. The flexMT is one somewhat stiff outer disk with one really stiff inner one in the middle off to the side, with the nails positioned somewhat over the empty spaces on the other side.
The assumption is that when the outer rim of the flexNExT bent, the part of the nails over the stiffer core wouldn’t bend, and so the entire bending force was contentrated on the part of the nail over the boundary.
With the flexMT, when the outer rim is bent, the nails kind of go along over their entire length. And the flexMT bends less, possibly.
On my doNExT, the entire implant is floppy and the nails aren’t positioned radially, so they go along with the bending also. I surmise that’s why mine are still alive. I may be wrong, it’s just a supposition, but I’ve done enough Von Misses analyses in my life to have a fairly good hunch.
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Pretty much that… plus size.
The larger the disc, the more of it will end up beyond the areas we could sall “flat” on out boddies.
And the more they stick out, the more they will be bent into a potato chip shape… thus aggravating this scenario @anon3825968 painted above.
Ex:
In my wrist, with my measures, I can lay down a 25mm diameter disc without having to worry much.
If I go beyond that, each mm larger will be a mm bent.
So I might be able to fit an EM in there, and only about 1/6 of it’s surface will be under constant pressure…
Which makes it so the pressure is much less than on the edges of a 40mm disk, which would cause 3/8 of the disk area to be under pressure.
Simplifying the process again…
Not only the “area” matters, but also the lever effect.
On a flexMN, you had only 2.5mm of “lever length” on each side. On the flexNExT you had about 7.5mm of length on each side.
These larger distances not only affect more the chips, especially on a flexible outer ring like the next one, but also cause more “damage”
Funny that the harder the implant is, the more damage it will deal to you. yet the more flexible the implant is, the more that damage will be translated into the implant.
Which should be a great thing!
If an implant is 100% flexible, even counting the solder joints and etc… then it should just “roll with the blows” and everything would be fine.
But as Rosco pointed out, if the implant is partly rigid and partly flexible… then all this energy/damage coming it’s way will probably hit stress points and we can see some shearing coming up.
Or… scratch all that, and the problem might be on the NFC nails themselves.
I do have 5 NFC nails converted to implant with glow resin, made by @amal, here with me.
When I received it I made some tests, mostly to see if they were working. Then I put them back into a box and stored.
Couple weeks later, I took them out, ran some more tests, all good. put them back inside.
now, another month later, I took them out and decided to test the glow resin charging, to make a final decision on placement, since I was planning an install within the next weeks.
For this test, I placed 2 nails on top of DT’s KBR reader, to properly check how strong would be the charge from the glow resin with 5 and 10 minutes of continuous activation, and the other 3 nails went on top of a ARC122 running an eternal loop of read/wait, to see the difference between those first 2, and then 5/10/30 minutes of blinking activation.
all good, all fine…
Except that one of the 5 nails suddenly stopped working after a bit less than 1 minute on top of the KBR.
Nothing else seems to activate it anymore.
All the others are still fine…
Got a flexMN, but I’m thinking about implanting it on my other hand and leaving the flexNExT as giant flexEM
About the floppy part of the flexNExT, I can definately tell that, when I move my hand, the floppy part bends and the stiff one doesn’t. The only LED left is the one which doesn’t bend when I move my hand
Is the flexMN completely stiff? Cause that seems a good idea
Makes sense… =/
Although the Nail I have here that failed… was completely flat, not connected to anything else. completely isolated.
being completely stiff is a good thing for the electronics, but depending on how small the implantee is, it might cause issues.
I think what’s important is that it bend uniformly, if the nail is over an area that bends, of that the nail be entirely over an area that does not.
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Funny unravel of events:
I tried and and tested the dead nail against KBR, ACR122 and PaSoRi. nothing.
I pressed on it a bit, tweaked around… Nothing.
So I left it on the side on my desk and decided to place the remaining 4 nails for a few uninterrupted hours on a field. force them all to die of exhaustion if they will.
Now, 10 hours later…
They are working fine.
So I was about to pack them all back into a box in my shelf, when I actually mixed the 5 bags…
Easy, all I needed to do was pass all 5 on the KBR, right?
Well… it did light up. 
So now the 5 are working.
Conclusion: I sure need more tests before being confident to get them in.
Also another conclusion, albeit I want to test this one more, goes about how the glow resin got charged up. That might belong to another thread though.
Yet my tests so far show that no matter if I charge for 5 minutes or 10 hours, the glow seems concentrated only on the immediate vicinity of the LED. and the increases based on charging time (as expected)… but seems to hit a plateau at 20 minutes (since the decay I have now, with 10h+ seems the same as when I last tested at 20 minutes, which was the same as my 45 minute test).
I might take a day to properly test that and make a new thread about it.
For now I am rethinking the placement I had in mind. Will still get them in but perhaps thinner skin will behave better, to allow the resin to charge as well from external light.
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Random thought: do your readers emit a constant field?
I have one here that behaves like cellphones upon “making contact”, meaning it sends out probe pulses and only switches to full power and attempts to select if it’s confident there’s something in the field. More interestingly, after trying to read for like 10 seconds, if nothing answers, it switches back to probing.
If I place one single glass blinkie over that thing, it won’t wake up. I can barely see the probe pulses. It would easily pass off as dead when the reader won’t play with it.
I know the ACR122U constantly puts out a field, but I don’t know about the KBR or PaSoRi. Could it be something like that?
Or, more prosaically, you have a flaky nail. Fungal infection maybe…
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Anyone know if Amal has gotten a chance to actually autopsy any of the failed flexnexts?
A couple… definitely the chip decoupling from the antenna. The LED failures are similar… passive components not well soldered to the pcb. Only one had a compromised coating but still under if this was due to handling during installation or removal
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the KBR yes.
I can tune my PASoRi to emit a constant field.
My ACR122U only looks like constant, but unless it detects a chip, even if I try to force it to be constant it is only pulsing at best. (another reason why I don’t like that PC mod chip they add to those readers)
The ACR is one of those readers that tries to be smart for you, with neat little tricks like:
Which is great for average use-cases, but not so great for someone who wants it’s readers to do out of the usual stuff…
@Coma Hope I’m not reviving a painful memory (considering you have it framed probably not 
) but did you end up finding up what caused this? Did they maybe identify the microorganism? I’m very curious
Nah, no problem - I’m not regretting anything and my hand is fine, so everything’s okay 
I finally managed to talk to someone partly competent in the hospital - and they told me they can’t give me (my own!) results. They have to send it to my GP, and now I have to find time to visit him to collect my results. Unnecessary complicated 
As soon as I have them, I will post them here for sure - dunno if they’re of any help, but who knows
Little update - I was at my GP and got the results. It was a “sparse” amount of Staphylococcus aureus (pretty much as expected), surprisingly with a resistance against Penicilin and Ampicilin. I’m a bit surprised by that because I rarely if ever took any antibiotics… but well, resistances seem to be pretty common by now.
Yep too many stupid people wanting / buying them for stuff and too many stupid doctors prescribing things unnecessarily
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Yep, and that stuff ends up in the water, together with the many antibiotics from industrial livestock farming… not really nice that it affects me, even though I eat no meat and tend to stay away from antibiotics until my doc forces me to take them, like in this case^^