I was doing something similar, needed a water tight housing and with no
external connections
i needed to supply power to the circutry, the best way to do this was to
totally seal the circut
and include an inductiveley coupled charging system, this would charge a
supercap or a
set of cells, and power the circut, the reason for the supercap and/or cells
is that if there
is any deviation on the power being supplied its not reflected in the
performance of the
circut.

Let me know if you ned a circut, i think i have it kicking around
somewhere..(if youre lucky)
from memory i was supplying about 2 volts over a distance of about 5 to
10mm.
this could be altered by changing the turns on the transformer.

Regards
Andrew


>I«m working on a project where the customer don«t want electric connection.
>And no batteries needing to charge, switch or anything like that either.
>Too dark/small/dusty to use solar power.
>
>It«s a kind of moving hose connected pressure air driven tool, that I«m
going to automate and improve somewhat.
>Current verison do have air-logic, but a microcontroller based will have
more facilities.
>
>So, I got plenty of air, standard pressure 7bar, filtered, dehumidized, oil
free.
>
>My power requirement is about 12V, 1W.
>
>Lifetime also is an issue as this is industrial, and noise must not be too
high.
>Cost is always an issue...
>Maximum alowed airelectric generator size is 0,5 litre.
>
>I have sketched of a number of solutions, but nu really good.
>Unfortunately i have no rotating part on that tool, (just cylinders) and
also the sensors need power when tool is at rest.
>
>Probably someone have been thinking about this before, and a good place to
ask is this list  :)
>
>So...??
>
>Thanks in advance.
>
>/Morgan
>Morgan Olsson                   morgans.rt@telia.com
>Morgans Reglerteknik, HŠllekŒs, 277 35 KIVIK, SWEDEN
>     tel +46(0)414-446620, fax +46(0)414-672324