this might be the solution to power requirments


  • If you have a turbine spinning in your body.. sure. But most people don't.
  • From a hypothetical standpoint, would it be possible to spin a turbine with blood flow?  The obvious flaw in this plan is that you need to temporarily sever a blood vessel.  Surgeons could install a device like this.  Is anything being made which already uses blood flow to power an implant?
  • As far as i know there isn't a good solution for that. Direct contact with blood have even higher requirements in terms of material properties than regular implants.
  • What about the rocking motion of the heart?
  • At least you wouldn't waste time guessing exactly where the blood clot that is going to kill you will form...
  • @Saal, I always knew it would be my fault when my heart fails.  At least this way I'll have a direct and literal hand in it.

    And since this thread has become preposterous anyway, what about the obvious perpetual motion we've got going on here.  A pacemaker that charges from the heart's beating?  Yeah, infinite power.  Forever.  And ever.  Amen.

    Back to serious.
    I honestly think that internal motion converted to stored power is a great way to approach things.  The particular device shown by @ansamech might not be the best nominee though.

    A low-tech approach like using a pendulum to wind a spring could store significant mechanical energy but then of course you're putting all that stuff inside.  Plus you have to understand analog watch mechanics enough to hack one into an implantable device.  Not a great nominee either.

    I've only seen induction charging for implants so far.  Has anyone seen other methods?  Does anyone have hypothetical methods they'd like to share?
    mechanical motion in different variants, small solar panels and induction are the some of the options so far.
  • I've never been one to withhold bad ideas, so here is something I just thought up:

    Take a tough squishy membrane filled with saline and connect some tiny tubes and a one way valve and a microturbine to it. Pressing on the membrane causes the saline to flow through the tube and turn the turbine. Ideally it would be cool to pump it a few times so that all the fluid fills a small part of the implant. Then the pressurized fluid can just flow through the turbine over time so you don't have to continuously pump it manually.

    There was a crazy energy harvesting idea I saw a while back that mimicked the tympanic membrane in the ear somehow and made electricity.

    I like this triboelectric thing. I might make something this weekend on a pendulum or something just to play around with it. I have tons of felt strips that might work.

  • @ThomasEgi "...small solar panels..."

    I had a thought about this, the amount of light getting though the skin is limited, so the amount electricity generated will be much less than a normal non-implanted solar panel.

    One way to help compensate for this is a directed light source. Kind of like those directed lasers used to power quad-copters. Of course you can't use lasers on the skin (at least not very high power ones), but the same idea should work. I.e. shine a bright light at the implant to power it. you could even strap the light source to body where the implant is to avoid the light diffusing (as long as the light source doesn't generate too much heat). As long as you avoid UV light, this shouldn't have any negative health effects.
  • @AmmonRa If you implant a solar cell, it'll have to be a flexible one; next look at the efficiency averages - on the high end of solar it'll be around 45-50% efficient. Inductive charging can get as high as 70% transmission, pump a higher wattage  and be relatively as flexible depending on the coil used. It's a cool idea, but overall inductive charging seems to be the way to go.
  • @geckogut oh sure, I would much rather inductive charging than solar. I'm not recommending solar, I was just thinking that if you _were_ using solar, this could be a useful way improve the total power.
  • @AmmonRa you might be able to get away with up to a 30mw infrared laser as long as you diffuse it to a larger area; infrared travels much deeper through skin so should be a bit more efficient. Plus infrared lasers are incredibly cheap.
  • There is absolutely _no_ need for lasers. Lasers are expensive, sensitive and a lot more dangerous for your eyes compared to LEDs. And in this application lasers don't even give an advantage. Strapping on a bunch of Ir-LED should work very well.
    The whole idea of bringing up solar based charging was to have an energy source that's not depending on external charging units. Regular sunlight would be a great source. Also, there is no need for flexible modules as long as there is a rigid enough frame around it to prevent it from snapping.
    Have a look at Amorton _EP120B.pdf
    they have a 25x11mm panel on glass substrate. As small as it apperas, it can fully power a smaller implant on a sunny day (even if you are in the shadows). if you go sunbathing those can easily generate a surplus. Even during overcast days those can lift a significant amount of energy and prolong battery lifetime. If the implant is very low power, using a rechargeable lithium coin battery and an appropriately sized solar panel could be used as energy providing solution without extra components.
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