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Topic: Sonar distance sensor underwater? (Read 1 time) previous topic - next topic

Stigern

Can it somehow be used to check distance underwater? Like a submarine sonar, check depth under keel etc.

Also, can the RF 315 or 415 mHz send underwater? is it possible?
I'm from Norway!

AWOL

#1
Sep 16, 2010, 07:52 pm Last Edit: Sep 16, 2010, 07:52 pm by AWOL Reason: 1
Quote
RF 315 or 415 mHz send underwater


Yes, but your antenna will be hundreds (if not thousands) of km long.

Common hobby sonar units are not waterproof.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Stigern

Quote
Yes, but your antenna will be hundreds (if not thousands) of km long.

Common hobby sonar units are not waterproof.


So you are saying that RF doesn't work underwater? Right?

And, what if I somehow wrap the sonar-module, so that it's waterproof.


I'm from Norway!

AWOL

#3
Sep 16, 2010, 07:59 pm Last Edit: Sep 16, 2010, 07:59 pm by AWOL Reason: 1
Actually, make that hundreds of thousands..

Yes, RF works underwater, but the higher the frequency, the lower the penetration, which is why the military uses VLF (3 - 30kHz) or ELF (3 - 3kHz), but this is still much higher frequency than your 415 mHz.
The Russians use 82 Hz, with a wavelength of over 3500 km.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

dezguy

I'm interested in building a fish finder for my ipad. I'd like to be able to use Arduino to send/receive a signal to a 200khz transducer, then send the signal to my computer for processing and graphing.

Has anybody tried this type of project?

I'm new to Arduino, but here is my basic plan:

1. Figure out how to interface the Arduino with a transducer from an old fish finder.
2. Send/receive signal
3. Calculate distance (similar to Ping tutorial)
4. Create serial sentence to send distance and signal to Processing
5. Graph/process signal
6. Create a display similar to a commercial fish finder

And, once I get this up and running - seek to port it to Objective C and figure out the serial interface (or bluetooth) with my iPad to be able to graph the data on the sweet display.

Any thoughts on this? is this the right approach? Am i missing something? Has anybody tried this before?

Cheers,
Mike

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