Underwater Modem

[D. Jones]

I am looking for a modem to work under water. The modem should be low cost and preferably battery powered. When I say under water I mean that a diver/vehicle will be working underwater and some sensors on him need to transmit serial (RS232) data to a computer on the surface. This modem should be able to transmit that data through the water without using a wire. The distance underwater to the surface is very small - about 25 meters max. Think swimming pool sized areas. I know of underwater modems that are for use at sea, but those are over the top in size, price for a swimming pool sized operation. Thanks

 

[Rich Grise]

I am looking for a modem to work under water. The modem should be low

cost and preferably battery powered. When I say under water I mean that a
diver/vehicle will be working underwater and some sensors on him need to
transmit serial (RS232) data to a computer on the surface. This modem
should be able to transmit that data through the water without using a wire.
The distance underwater to the surface is very small - about 25 meters max.
Think swimming pool sized areas. I know of underwater modems that are for
use at sea, but those are over the top in size, price for a swimming pool
sized operation. Thanks

You've actually got two questions here - the "modem" part isn't hard, just
use an ordinary modem that's built just like the rest of the electronics.
(i.e. waterproof). The part that's stopping you is the comm link. Just use
a couple of fish-finder transducers and AFSK.

Good Luck!
Rich