> On Jun 9, 2016, at 12:21 AM, Tim <xxxxxx@little-possums.net> wrote:
>
> On Thu, Jun 09, 2016 at 03:03:13AM -0400, Richard Aiken wrote:
>> The muscle is moving anyway. The only extra effort comes from
>> carrying the extra weight and whatever additional friction is
>> involved in rotating the devices coils.
>
> Plus the electromagnetic drag from converting the kinetic energy to
> electrical.

The three laws of thermodynamics:

1) You can’t win.
2) You can’t break even.
3) You can’t get out of the game.

This energy isn’t ‘free’. you won’t notice it because it’s so minute in comparison to the energy you’re expending to walk. However, since it’s so minute (and if you look at figures 5 and 7 of the Romero, Neuman and Warrington paper, 117µW is quite optimistic; most power generation was between 1 and 10 µW.

This is at the lower bounds of even the most efficient sensors we have. It’s absolutely not sufficient to recharge anything with a significant power draw, power communications or anything like that.

A far better solution is a tough solar panel on your pack.

--
Bruce Johnson
University of Arizona
College of Pharmacy
Information Technology Group

Institutions do not have opinions, merely customs