The ever-shrinking size of electronics and sensors has allowed wearables to help us quantify more and more about ourselves in smaller and smaller packages, but one major constraint is the size of t…
  • JustEnoughDucks@feddit.nlEnglish
    15·
    3 hours ago

    I don’t think people realize how extremely little 50uW is.

    For a standard 3.3V microcontroller assuming a 95% efficient voltage regulator will be a current of 14.4uA. Just having the HSI master clock enabled on one of the low power STML0 chips is 15uA. This will literally only the clock. That is 0 sensors, 0 communication, 0 IO, nothing useful at all. For reference, reading SPO2 with a very efficient maxm86161 takes 10uA by itself in ultra low power mode with low accuracy and not counting the max leakage current of 1uA. For full operation, you need about 1000x-10000x that amount for short bursts.

    “Oh but it can cHaRgE tHe BaTtErY”

    Let’s say the device has a standard 100mAh battery (apple watch had a 228mAh or more). At 100% efficiency with absolutely not one millijoule being used by any other electronics (which would never ever happen, it would at the very least need a boost converter), it would take around 277 days to charge up that tiny tiny battery.

    Let’s take another example of an even smaller battery. To charge one side of the airpods 3rd gen (0.133Wh battery), it would take 110 days per ear

    This is one of those free “energy harvesting” fad BS based in nothing but wishing and marketing. It is an interesting learning project for wireless antenna beginners, but that is the extent.

  • qisope@lemmy.worldEnglish
    25·
    10 hours ago

    I guess at least in a future where I can be blinded by a targeted EMP attack that blows out my powered contact lenses i can perhaps also get some replacement electronic eyes (then go blind again when they fail out of warranty)

    • easydnesto@sh.itjust.worksEnglish
      13·
      10 hours ago

      Powered contacts would be awesome! Especially if they can let you zoom your eyesight to a degree. Also, skin powered hearing aids!!

      • Echo Dot@feddit.ukEnglish
        1·
        5 hours ago

        There is a lens material that is currently in development that can change its optical properties based on an electrical current, so it’s entirely possible.