E-mail me and I'll hook you up with an old swabbie I know who can probably
build exactly what you need.

I also know that some line of sight devices have been made using blue-green
lasers, that allow P3 Orion aircraft to communicate discretely with US subs.


"Eric" wrote in message
. ..
Hi,

Don't want to get side-threaded, but I got hit up on a project idea that
should prove practical, educational, fun, and just plain neat.

What will be required, however, is a wireless data pipe down to a depth of
~50 feet (15m). Unfortunetly, it will have to be wireless.

(Obviously, such a link will also have to be acoustic and not RF.)

I can't go outside of "consumer" price tags though. By "consumer", I'm
thinking up to ~$500.

Depth time on a full battery charge of at least 30 mins is prefered.

Standard data ports, such as ethernet or RS-232.

I'm not concerned about the data rate through the water, or what
mechanism/schemes these modems use going through the water (proprietary,
I'd
imagine), as long as the data ports use standard communications.

If the modems behave and function (from their physical ports, not
modem-modem through the water) as a standard "analog modem", I plan on
using
just a terminal program with the surface modem. Port speed should be a
non-issue, as long as its standard. Even just 300 bps will work fine.

If the modems behave and function (port side, again) as standard "network
cards", then I'll be doing TCP/IP. Again, only need the bare minimum data
rate for function.

It would be nice if such modem could function like both above, giving more
flexibility, but I can do with either.

Its not going to be passing graphics, images, or anything extensive
through
the water. In fact, the relevant data it will be passing will only be 15
to
20 characters in length.

I "thought" that I had seen such an (consumer) animal in the past years
ago,
and mentally noting that it "neat", but I may be mistaken. My googles
are
only turning up such modems that are either commercial or military,
obviously outside my reach.

Just throwing this out in hopes that maybe someone has seen such an animal
with a consumer price tag -- or possibily an idea or two on how to maybe
creatively homebrew such hardware, relatively inexpensively, out of
existing
hardware. If need be, I can kludge up power supplies and waterproof
casings
(able to withstand 15m) for anything creative...

Thanks!

Cheers
Eric