On 9 Jun 2016 at 1:33, Richard Aiken wrote:

> On Thu, Jun 9, 2016 at 12:14 AM, Tim <xxxxxx@little-possums.net> wrote:
>     On Wed, Jun 08, 2016 at 11:07:17PM -0400, Richard Aiken wrote: >
>     Speaking of reducing loads and all those batteries to carry > . .
>     . why don't they give everyone one of those modern hand-crank >
>     generators that are about the size of a smart phone?
>
>     They are pretty pathetic.  A good one will generate about 10
>     watts, while seriously tiring your arms.
>
> Well, there is also:
>  http://www.wired.com/2008/02/knee-brace-harv/#seealsocad0110d22d6d54
> 01371dbc7005ce85 5
>
> A 3.5 lb knee brace that generates 5 watts from ordinary walking,
> without imposing extra effort on the wearer. Down toward the end of
> the article the inventor says the military has shown interest . . .

A few things. Firstly, it absolutely does reuire extra effort. It generates electricity, so it's
consuming power from your muscles. Also, 3-1/2 pounds of extra weight at the knee
absolutely adds to walking and running effort. Then there's the way it's going to get
bumped all the time, it will have to be a quite different shape from the one in the article
if it's to allow the user to kneel or crawl or go prone. It's also going to need a really
good attachment system if it's to be worn all day while marching and running without
causing chafing, skin irritation, etc. It'll also need to be ruggedized, of course.

It might be best to build it into a set of protective or armoured kneepads.

Once it's lightened, toughened, and made comfortable to wear for 16+ hours a day, it'll
be ready for actual use by the troops that need it (i.e. light infantry).

Oh, one other thing - recharging devices are no use at all until all the various batteries
in use are replaced with modern high-capacity recharagebles. Many military devices
use non-rechargable batteries because of their better power density, in an attempt to
lighten soldiers' loads, at the expense of a greater logistical load.

> This seems to be a formal report on a very tiny motion-capture
> generator (2 cubic centimeters), that generates 117uW (not sure what
> the "u" means) at "high accelleration squared to frequency (ASTF)"
> body locations (which I assume means either side of each major joint
> involved in walking). If you put one on every high ASTF location, how
> much power is that?

uW means 'micro-Watt', so it's a tiny amout of power.