Acoustic Modem For A Hobby AUV

Hi,

I'm building an AUV for hobby use, however I'm having trouble whe it comes
to communications. So far I've considered sending DTMF tones through 2, 2
way radios, and encoding sets of numbers on R/C equipment but neither will
travel/penetrate far enough (<3m).

It needs to be a duplex system capable of transmitting 32 on/off comands and
8 values (0-255) through about 100m of water.

So far I've found lots acoutic modems except they are more for industrial
use and so are rather high-spec compared to what I need.

So, can you guys suggest where to start (happy to learn any new skills I
have to) or if you can think of a better method I'm open to ideas,

Regards,

Michael


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