Fully submersible Arduino controlled submarine

Hello I am trying to build a small submarine ( about 1.5' by 5" ) and I am trying to figure out how to do the communications. My original plan was to control the movement with 315 mhz rf transmitters and receivers. Then use a raspberry pi for video feed through wifi. I realized the rf will not work unless it is at a much lower frequency and I haven't even looked into the wifi signal. Just curious if anyone had any ideas on how to fix the signal issue.

The real submarines use S.O.N.A.R.s. (Sound Navigation And Ranging)
S.O.N.A.R. use ultra low audio frequency

Can you make a SONAR underwater modem using FSK modem concepts ?

The real submarines use S.O.N.A.R.s. (Sound Navigation And Ranging) S.O.N.A.R. use ultra low audio frequency

Military submarine comms use ULF radio.

Military SONAR is usually passive - the last thing a sub wants to do is tootle around the depths shouting where it is.

Active SONAR is not ultra low frequency audio

Is there a way to use SONAR or ULF with arduino?

Is there a way to use SONAR or ULF with arduino?

I don't know. Why don't you send the Navy and email and ask them ?

SONAR is the underwater equivalent of RADAR. It is not generally used for communications.

I suspect the model submarine won't need to transmit or receive at the depths, or over the distances used by military submarines.

Maybe you could try out the radio devices in a bath and see how well they perform.

What is the licensing regime for 27MHz radio control?

Many people build model submarines - what does Google say they use?

Maybe the model submarine could float a buoy to the surface when it needs to communicate - just like the real thing.

...R

Robin2: SONAR is the underwater equivalent of RADAR. It is not generally used for communications.

Don't confuse the transmission channel and the payload. SONAR uses audio frequency (between 3 kHz and 10 kHz) because frequencies above 100 kHz are absorbed by water and therefore unusable. Another important point: the size of antennas --> with low frequency antenna is big.

68tjs: SONAR uses audio frequency (between 3 kHz and 10 kHz)

68tjs: The real submarines use S.O.N.A.R.s. (Sound Navigation And Ranging) S.O.N.A.R. use ultra low audio frequency

Make your mind up.

You could also just stick an antenna up above the surface, either with a buoy that follows by cable, or sticking out of the sub. However, that will limit the depth and risk catching on things, though I imagine it will be limited anyways since it is small. Really depends what you are trying to do with it. As stated, RF and water don't mix well. Especially salt water.

Green laser.

How deep is the submarine supposed to go? If it's just a toy going in a swimming pool, just use a cheap 2.4Ghz transmitter and receiver combo and read the servo channels from the Arduino in the sub. You can hack the transmitter, too. Take a look at what I did here with an Uno:

https://www.youtube.com/watch?v=ff8HUavKR1U

Join a club. 315 MHz is better than 2.4 GHz. Some fans do this although its. A bit escoteric. Range underwater is very limited. Im a bit unsure why peeps do this, underwater you cant see it , i prefer aircraft where i can show off my long learned skills of crashinhg my lovingly built model into the nearest tree.

Sonar is utterly usless for control, for video it would probably take you a year to transmit a low res video picture, band width is worse than morse code.

jacksip: Is there a way to use SONAR or ULF with arduino?

Yes. You would need a power amplifier for the sonar though.

ULF may be possible as not much power is required. The uk is only about 900 km top to bottom though, so not enough room for the aerial.

There is a Navy sub communications center near where I live. They can send messages to subs underwater anywhere in the world. It transmits at 24-28Khz at about 1.2 MegaWatts. The antenna system runs miles between mountain tops. See http://en.wikipedia.org/wiki/Jim_Creek_Naval_Radio_Station

Its still operational and really messes up local radio when its transmitting.

Just thought I'd share.

Will they let you borrow it for an hour ?

http://en.wikipedia.org/wiki/Underwater_acoustic_communication

http://en.wikipedia.org/wiki/Acoustic_release http://en.wikipedia.org/wiki/Underwater_acoustics

raschemmel: Will they let you borrow it for an hour ?

Probably only enough time to send "Hello World"

...R

How long would that take though ?

In early developmen i heard somewhere that they connected up unused telephone or telegraph poles up the side of the us?