Even better
I actually want one of those for my collection
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Most pacemakers are powered with a (non-rechargeable) lithium-iodide battery and you don’t hear about these things catching on fire inside the wearer’ chest. I guess it just depends on how well made the device is. Hell, the first pacemakers were even used plutonium: what self-respecting grinder wouldn’t want one of those eh? It’s not like some member of this board didn’t have radioactive things implanted in them already 
Anyway, for less extreme solutions, LiFePo4 or NiCd batteries are also options for a rechargeable device, as they are safer chemistries.
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You don’t hear about pacemaker batteries catching fire in someone’s chest because the primary failure state of a most batteries is a short caused by either: cell penetration by a conductive object, or across the unprotected contacts. If something gets into your chest cavity far enough to short or damage a battery, you have more serious concerns.
These battery chemistries still suffer from the same failure state. If they get penetrated, damaged, bent, or the PCB is compromised, they release large amounts of hydrogen and other gases, often accompanied by flames. Even some kind of rigid epoxy resin encapsulation is not going to withstand the outgassing.
To each their own, but I’m not down.
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Fro my 2 cents, it’s the gasses which present the most risk. That’s because an implant, by it’s very nature, must be sealed completely. If you mistreat basically any battery in any way, like putting a little too much power into it during charging, then you get gas production. That gas production, even in modest amounts, will crack open a sealed implant like nobody’s business… and once you let bodily fluids in, you will likely have only a very short amount of time to live before things go catastrophic.
For these reasons, we don’t make consumer grade implants that contain power cells of any kind. As I said above, we keep our eyes on new battery chemistries being worked on.
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Like solid state batteries? That looks exciting. But no that’s why I want to attempt this with qi charging or something as an active power source( haven’t done the research if this is even possible).
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How viable would it be to use a transdermal like @Leeborg 's project ? Plug a charger on to the transdermal to power the storage? I thought about some kind of medical-type port (but much smaller) but then there’s the whole risk of infection thing to worry about. Perhaps I’m thinking too far into the future 
I feel like I’d be more worried about snapping the storage chip in some kind of fall / blunt force trauma.
That’s why I want to do it on a flexible pcb so it has the ability to flex and move with trips and spills. And I kind of want to design like a dermal piercing that is a USB plug maybe one day(I’m not a biologist or electrical engineer). Like people get trans dermal piercings all the time if you do the same, but with leads to a chip it might work and you could put a waterproof plug protector to keep the plug itself from eroding, but it’s still a super scetchy idea.
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We have played with this in some retro spec. We’ve looked at attaching dermal posts to a AtTiny85 and coating it. The USB wires would run through the hollow dermal post.
Personally I prefer implant microboards that are externally powered only. As many have stated putting batteries in you is not feasible currently.
Yes pacemakers and what not have them but they also have “Short” lifeapans. Not meant to last 50 and 60 years.
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How did that go?
Like most dermal and open surface structures it’s all about the personal body, 1 person had a successful heal 2nd person had a rejection after about 6 months 3rd had rejection a couple months after implantation. Having “open” wounds is finky.
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Did the connectivity work? Or did you just test hollow dermal posts?
Yes the connection worked. It’s would nice to see a screwable jack developed for a dermal post.
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Then the only other “safe” option is supercapacitors. The problem with those is, their energy density is about 1/10th that of lithium ion at best.
Also safety is relative because, at the end of the day, you store a large amount of energy in a device under the skin. Whichever form of storage you choose, if it fails for any reason, that energy has to be dissipated somehow, either in the form of heat, or gassing out or something. Since there are no totally safe energy storage methods, at the end of the day, it all comes down to doing QA at a level not commonly applied to consumer-grade products.
I really don’t agree with that. Storing moderate amounts of energy at a low voltage potential in a supercap (especially when they get more efficient in a few years) is exponentially safer than any of the chemical energy storage mediums available.
Most supercaps max out at 2V-5V. Even in the worst case scenario, that voltage will not travel through more than a few mm of tissue or a few cm of blood, and it’s all the differential we’re going to need for most implant use cases. Even if it doesn’t last more than an hour or two, then we can start to utilize resonant charging technologies to top up the implant in our homes, cars, and workplaces.
No one has mentioned peg leg implant? Take a look
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Except for
- #3 by Satur92d - Check out the http://pegleg.org/ Pegleg
- #20 by Bluethebox1d - Thats why the pegleg only is powered on when it has a qi powerbank held to it
oh, and
#37 by Devilclarke4m - No one has mentioned peg leg implant? Take a look
But other than you three, Nobody
and now ME !!!
But other than us Four, Nobody else
Voltage isn’t the issue. The issue is, if the device fails and dumps all the energy it stored as fast as it can, will it turn into searing heat or uncontrolled chemical reactions happening inside your body? The more energy stored, the higher the danger, because all that energy has to dissipate somewhere.
Of course, capacitors (even super-ones) store less, so the danger is naturally minimized. Still, they have such low internal resistance that they can generate scary currents when they short out. And since most high capacity caps are pumped full of nasty chemicals, they can very well go pop inside you and release them into your bloodstream, even if they don’t store a lot of energy compared to a similarly-sized lithium ion cell.
There really aren’t any safe energy storage devices, only safer ones - simply by virtue of energy having the potential to be released uncontrollably. That goes for batteries, as well as for coiled springs, pressurized scuba tanks or speeding cars: anything that stores energy in any shape or form is dangerous.
I meant in this thread 
But I just spotted them oops
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mine has been “healed” for 3 months and still sometimes acts up. Can’t say i’d recommend for mass consumption though I am pleased with it personally. I like the idea of using it as a charging port though…
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