I would need to transmit data in salted water in both ways on a distance of 40 to 50 meters maximum with no cable.
The quantity of data is not important only constarint is to use to much energy and not to expensive. Apparently the best option would be ultrasound:
I found some interesting device on internet:
As I'm a mechanical engineer, I have no clue on which material I should buy to test underwater data transmission...
So I have 3 Questions:
1/ Is the ultra sound option the only one for my application, if not, what do you recommand ?
2/ In the case of ultrasound communication, which reference of equipment should I buy (maybe in the link I gave before or you have better options?)
3/ If you think of other options than ultrasound, do you have any reference of electronic system I should buy for testing?
Thanks a lot,