From: Ian Stirling
Subject: Re: Tracker implant for children - Real or Fake?
Date: Mon, 9 Sep 2002 01:00:42 +0000 (UTC)
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NNTP-Posting-Date: Mon, 9 Sep 2002 01:00:42 +0000 (UTC)
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James Meyer wrote:
> On Sun, 8 Sep 2002 18:57:10 +0000 (UTC), Ian Stirling
>>There are unfortunately only a few ways to generate power inside the
>>body, without external rechargers.
> A solar cell close to the skin's surface? I suppose the sun could be
> considered an external recharger though.
Another fairly poor option.
It can't be too close to the skins surface, or it will work it's way out.
It's got to be ~1mm deep or so.
And it's got to be flexible, as well as biocompatible.
And it's got to be large in area to pick up sun, and has to be on an area
of the body which picks up sun.
This means you've got to implant in the hands or face, both of which are
horribly sensitive to damage, especially if you are trying to insert a
relatively large solar cell just under the surface.
From some quick ballpark sums based on shining my laser pointer through my
finger, I think that perhaps .5% of the light will get through 1mm.
Add 10% conversion efficiancy, and that's .5mw/cm^2.
Let's assume 10cm^2, that's 5mw.
Assuming an hour a day outside, a third of the time facing the sun, and
neglecting clouds, that's about a couple of milliwatt-hours a day.
You can do better with a small battery charged every year.
> Two contacts spaced a few mm apart could pick up myoelectric? potentials
> (nerve signals) and rectify them for DC power.
You'd do better with a tritium glow-stick, and a solar cell.
Plus, do you really want to get close to nerves, with the potential to
http://inquisitor.i.am/ | mailto:email@example.com | Ian Stirling.
If it can't be expressed in figures, it is not science, it is opinion.
-- Robert A Heinlein.