ARDUINO COMMUNICATION

There are several ROV designs and commercial products based around Arduino.  One of the more notable names are the SeaMATE series ( MATE - Marine Advanced Technology Education :: SeaMATE ROV Kits ).  These have different levels of complexity in assembly and options.  I don't have a connection to them; I'm just aware of their products.

Your search area is quite large (10k ft is about two miles in one dimension, unless that's a typo), which will cause difficulty with control (that's a LOT of wired connection).  600ft is a fairly modest depth, although most less expensive underwater cameras are usually only rated to about 320ft.  If you're not familiar with the electromagnetic physics of water you might want to research underwater RF communication (unless you're thinking of something that's pre-programmed to search a grid or whatever).  You're most often limited to using physical wires.

You might want to research the idea of using this in cloudy water.  One of the problems that recovery divers have is an inability to see in most fresh water bodies.  I've done recovery diving, and most often you're exploring by feel rather than vision.  The more effective techniques for visualization (FLIR, sonar) in murky water are typically very expensive, fairly large; and in the case of FLIR, don't work well for a body that's the same temperature as ambient.

I would suggest you Google "Arduino underwater ROV".  You'll get plenty of hits for builds, code, videos, and commercial products.

10k was a typo.

There are some cases of law enforcement looking for bodies.  One case a couple on a snowmobile went through the ice on a lake. They searched the lake but they did not find the bodies until the spring ice out. I knew the couples son.

on another occasion some one cut up a body and threw the body parts in a river.

both of these searches and others were in waters where you could not see your hand more then 6 inches in front of your face.

My idea was to make kind of like a GPS for use in the water.  They have the stuff available for like the submersibles that Bob Ballard used to explore the titanic.But that stuff has a cost of $500,000 plus.

I had the software at one time where I could pinpoint the location of an item within about 1 ft an inside a cube 1000ft x 1000ft x 600ft deep.  All I needed was to know the depth and the distance from each corner of the cube on the surface.

By putting a buoy on each corner with a transponder on them and a transponder on the ROV, which would be on a tether, a radio link to each buoy and a laptop to control things you are all set up.

The only thing stopping me from having a working system is tofind a good transducer that I can afford.  They cost about $1200 each.

I used to have all the software to run the system but that was all lost when my friend died and his wife gave his old computer away.

Understood on the typo.

Sorry about the circumstances you're looking at.  I grew up in Cleveland, and recovery had to wait until the spring thaw on more than one occasion.  That's an ingenious idea for a fire-and-forget type of system.  As you say; the technology is available, if you have really deep pockets.

I'm not a recovery diver (I'm an electronics engineer).  There aren't many divers where I live (any body of water of any size is murky fresh water), and law enforcement sometimes asks for volunteers.  What we've been taught is to use touch - Below about 8ft most fresh water is completely black, even in bright sunlight.  Cadaver recovery is largely feeling around the bottom or objects that could tangle a body up.  Silt/mud are semi-liquid, trees and brush are rough-surfaced and hard, rocks are obviously hard; a human body will be fairly soft, once it's been in the water for a few hours.  It can be difficult to tell a human body from an animal body (especially deer, raccoon, and coyote), unless you can feel the fur or snout.  When the water is 35-50F your hands go numb fairly quickly; and you can only dive for about 15 minutes at a time, with an insulated drysuit.

An ROV, obviously, isn't so limited by temperature.  I'm wondering if using the same search modality would work well for an ROV.  A "homemade" BarCol Impressor or Durometer (Reference Guide - REX GAUGE DUROMETERS) might be used to "poke" along a grid or plane and look for soft objects.  That's essentially what human divers do.  I suppose you could put multiple sensors on a rotating drum to allow it "walk" an area looking for soft objects.  I don't know what value on the Shore Hardness Scale approximates a body, or could define a maximum value.  You'd likely have to go to a morgue or funeral home and test.  This, obviously, wouldn't work well on a completely frozen body, but that's actually fairly rare underwater.

Those sensors are essentially spring-loaded linear actuators that compare a reference (the end of the column containing the test rod) to the depth the device under test allows the rod to enter.  You could mimic that with a soft pot or whatever, to measure the distortion.

That's a great positioning system.  Sorry you lost your coordination software.  That really sucks.

My idea at the time was for the frozen lake to put holes in the ice and

put in one of the transponders at 3 or 4 locations the put the ROV in

that would tow a side scan sonar fish.  By using the locator you could

know the exact location of the ROV.

With a little extra programming you could set up a search pattern and

direct the ROV in a predetermined pattern.

or have a read out device on a diver and direct them where to go and

know their exact location.

The most expensive part of the design is for the transducers.  All of

the transducers for depth finders fish locators are directional,

typically a 60 deg cone.  What you need is an omni directional

transducer and they cost a $1000.00 or more each.

I have found on the internet people are making cheap ones using piezo

element to make their own.  They put one in a plastic container filled

with mineral oil and then it is waterproof.  I am not that much up on

electronics any more. But it seems with the new Arduino boards it would

seem simple with the help of a transistor or 2 to have the Arduino give

a 60Hz pulse about 10 MS long to the Piezo element. The piezo element is

supposed to act as a hydrophone.

I live in Algoma, Wisconsin right on the Anaphee river and Lake Michigan

harbor entrance is just about 1000 yds.

So I have the perfect test area.  Now with the ice on the river it would

be easy do do some range testing.

More later.

Bob Nelson

Outstanding ideas Bob!  Please do post more as you go along!