I am looking into constructing a small submarine with a Raspberry Pi. This is just for a hobby project but my idea is to have it communicate with the surface wirelessly. I know that normal radio waves will not work very well so I was thinking of using some type of Ultrasound device where a transmitter/tone generator is placed in the water and the submarine has a receiver/microphone that can pick up the sound waves transmitted.
I have read that sound waves are easily transmitted underwater so this is where I came up with this idea. I am wondering if anyone has already done a project like this in the past or knows where I can find more information on it? I have never really worked with sound/wireless transmission so its all very new to me. Any help is greatly appreciated!
Best Answer
Device is called ultrasonic transducer and it's freely available on a market.
For communications you will need MFSK modem
http://acomms.whoi.edu/umodem/
http://cseweb.ucsd.edu/~kastner/papers/oceans10-low_cost_modem.pdf
or write your own protocol and software.
Note that communication will be short range, if it's ROV and you don't consider it to be AUV it's better to use simple Ethernet cable.
Military submarines also use for underwater communications ELF, VLF radiowaves, so you might also consider this option for AUV, but data rate is very low on this type of systems.