Submarine Wireless

Hello! I really need everyones help. I am PLANNING to build an Arduino Submarine, along with an Arduino Remote for it. My problem is that I need to have the remote and the sub communicate. The remote will send commands to the sub, and the sub will send feedback. The sub will be underwater, and the remote above water. The sub will move throughout my pond. So, i need some form of wireless communication, that works underwater (The signal sender doesn't have to be WET in the water, as the INSIDE of the sub will be dry. The signal sender could be housed inside the sub if necessary) and the signal sender has to work at an OK range throughout my pond.

Also, it would be preferable if the sender could just accept Serial text commands and send serial data, and the receiver could input the Serial Data as Serial text back into the Arduino. Simple Serial communication. (Just wireless)

Any ideas? I would love your help! :)

Depending on the depth, radio doesn't work well or at all in water.

jremington: Depending on the depth, radio doesn't work well or at all in water.

Even if the radio is housed inside the air tight sub? (The water is not that deep. You could pretty easily wade in it)

What if a radio antenna sticks up and out of the water, so the only thing above water is the antenna? (Not ideal)

Also, any alternatives to radio?

Green laser

WesleyRTech: Even if the radio is housed inside the air tight sub? (The water is not that deep. You could pretty easily wade in it)

No.

What if a radio antenna sticks up and out of the water, so the only thing above water is the antenna? (Not ideal)

Good idea.

Also, any alternatives to radio?

Cables work well, especially for the size of most ponds.

Just an idea: What about ultrasonic sound? Sender and receiver will have to me submerged, but sound propagates through water very well. Whales communicate with it AFAIK over half the globe

Sound seems a good idea. But you needn’t run at 10’s of kHz - whales don’t!

Remember the old dial-up modems? I think they used 2 frequencies
1100 and 1800 Hz? one for a 1 and the other for a zero.

With suitable transducers I think that could work quite well
with UART-style protocols.

regards
Allan.

I hesitate to suggest sonic communication. If it does actually "work quite well" then there would be $5 units available on Ebay and AliExpress with free shipping. Drone submarines would be as common as drone quadcopters.

$5 of cable and silicon caulk will work quite well.

MorganS: I hesitate to suggest sonic communication. If it does actually "work quite well" then there would be $5 units available on Ebay and AliExpress with free shipping. Drone submarines would be as common as drone quadcopters.

$5 of cable and silicon caulk will work quite well.

I doubt it: what is use of a submarine? You can hardly see it, you can easily loose it (i.e. got caught by some underwater plant) etc. Someone may want to have something like that but the market will be limited.

On the other hand on ebay there is plenty of "RC submarine" stuff. i would suggest what RC they use and if it works.

Actually, ultrasonic does work quite well under water. Radio also can work underwater, but it depends on a number of factors - conductivity of the water (salt water is worse than fresh) and the frequency (look up "skin depth"). Years ago, they were able to communicate with submarines while submerged. They used a very low frequency which will penetrate deeper - see this link to Jim Creek for more information - they were running at about 28khz and the antenna stretched between two hills. Your best results are going to be with ultrasonic though - if there are going to be more than 1 sub (or anything else using the same method) nearby, you might want to consider sending/receiving the data in "packets" sort of like Ethernet or some other method that has a header that identifies source/destination. One issue you may run into though with the ultrasonic is exactly what make depth sounders work - the sound reflects off various surfaces, so you have possible multipath issues (you get multiple copies of the signal from different directions as they reflect around).

Maybe some old style dtmf telephone modules are available for encoding numbers as sound.

Or th floating antena thing should work, have a small raft with radio afloat, that would be very useful to have visual feedback of where the hell has gone that sub and to recover it in case anything goes wrong

blimpyway: Maybe some old style dtmf telephone modules are available for encoding numbers as sound.

Or th floating antena thing should work, have a small raft with radio afloat, that would be very useful to have visual feedback of where the hell has gone that sub and to recover it in case anything goes wrong

Ah yes "Sub 54 where are you?" (only the older folks in the states will probably recognize that) :)

One thing you could do is have a low power electromagnet that holds a ferrous piece of metal as part of the ballast system. If it fails or the batteries go dead etc, it drops the metal and surfaces (unless it is tangled in something of course like that old fishing line ... )

I do not think I'm going to use the whale old sub system, it sounds too complex for me to handle.

So far I have heard 3 alternatives.

1 -

AWOL: Green laser

I have no idea what you mean. Could you elaborate?

2 - Someone said that having a radio antenna sticking out ABOVE the water was a good idea. This way the signal would travel up to the top of the antenna, then transmit through the AIR to the receiver.

What kind of module would be good for that? (If possible, as I said before I would really like plug-and-play Serial data. The sender arduino would send serial text to the radio module, the reciever would send serial text to the receiver Arduino. If this is not that simple, I am willing to bite the bullet and do complex stuff)

3 - Cables coming up from the sub, directly lined in to the remote would be a last resort- the communication would be best wireless.

Thanks for the responses so far!

bang a hammer on the hull. you can hear that a mile away.

use a stepper to swing a hammer and wack the hull.
use a solenoid, and ping it.

creating sound and listening are common.

dave-in-nj: bang a hammer on the hull. you can hear that a mile away.

use a stepper to swing a hammer and wack the hull. use a solenoid, and ping it.

creating sound and listening are common.

The sound would muffle in the water.

Actually, sound carries very well underwater. It is also much faster than in air (something like 4,000 feet/second instead of the 1100 feet / second in air). It carries much farther too - makes divers nervous when they are near a ferry terminal for example - sounds like the ferry is right on top of you (been there, done that). Higher frequencies don't carry as well as lower ones do, but they still do quite well.

WesleyRTech: The sound would muffle in the water.

it that what you found when you tried it ?

do you realize that [almost] every post has been about acoustic frequency and that water will muffle every acoustic frequency ? what you are looking for is an acoustic frequency that has enough energy to retain enough of the original signal at the receiver in order to distinguish the noise from the signal.

but if you did any research, you should know that already.

it seems you have been shooting down every suggestion because you are not familiar with the requirements or the technology. do you honestly think that someone with years working with electronics can give you everything you need to know in 1 post of 4 sentences?

take some time to do some of your own research and you will find the details you need to make your device. all you are going to get from us is what to search for, you need to do your homework.

before you post some snip answer, understand that we hear :

"that requires my understanding of the technology and I am clueless, please don't post things that assume I know the fundamentals of this, or make me think or require any work on my part, just post links to things that do not cost more than $1 and have code already written"

sorry if that sounds harsh, but you have put out some effort if you are not assembling a kit that someone with knowledge put together for you.

I have no idea what you mean. Could you elaborate?

m A laser which emits green light.

AWOL: Quote

I have no idea what you mean. Could you elaborate?

m A laser which emits green light.

I think he wants this link

Excellent Dave !! Exactly what is needed :)