Lost drone detector (underwater of course)

[space_goast]

Hey everyone, I have come here to find treasure I lost myself haha. Long story short, I'm trying to determine if I can build a budget detector that can find a drone underwater with a depth ranging from 4ft-15ft.

I am an electronics hobbyist so I have arduinos, raspberry pis, wiring, etc all laying around. Best case I am just recovering my gopro and maybe frame, electronics I'm sure are long dead. There's also the possibility I don't find it at all because it's in a murky black florida pond with several gators that live in it (So I'm not going swimming/snorkeling to find it). I already made an 8 foot long waterproof camera PVC pipe with a video screen, a friend paddled around while I looked through the video screen but visibility was only about a foot and I am searching about a 400 ft squared area.

Most metal detectors are understandably designed to be handheld and find precious metals not too far under the ground. I am curious if I just scaled up one of the typical designs to a large coil (1 square meter?) and tow it behind a kayak if it would able to detect a drone around 1 sq ft. size (carbon fiber non ferrous frame, gopro, brushless motors with neodymium magnets, camera, some small electronics). Would like to keep price down to $50 or so since I am gambling if I can even find my drone or not, keeping in mind I have a lot of electronics already.

So my main two questions are:

1. Is it reasonable to build a setup that can detect such an object at those kind of depths underwater? If not, having to manually scan a detector underwater becomes very difficult when I can't get in the water
2. Is the price reasonable or am I going to spend $300 to build a unit to hopefully recover $300 in equipment?

[nickel_n]

i think
for a small and shallow area you should be better off with a rake or a modified scallop dredge type of equipment

https://en.wikipedia.org/wiki/Fishing_dredge

[space_goast]

I've considered it but even a pretty small dredge type net is a couple hundred dollars. That combined with the fact that the search area is a couple hundred feet off shore, and it's a 1.5 Mile walk from the nearest road makes it really difficult to bring anything other than a light kayak/canoe. Even that is very tiring for the distance travelled.

[space_goast]

I did some more searching for nets and a 20ft wide one is $35. That might be a viable option, it would be tricky to reliably set and drag but not impossible

[Altra]

A lot of people are magnet fishing these days. Search youtube. Its cheap and low tech. I know drones are mostly made composites and plastics, but the motors should have enough iron to be attracted.

[space_goast]

I have a friend who tried magnet fishing his drone in a pond right behind his house every day for 3 months. And that pond is a fraction of the size I need to search. Trying to cover the most ground possible the most reliable way (with the camera and casting you are just hoping you stumble on it).

[Skippy]

I agree, strong magnets are worth trying. Both attached to a rope and lowered vertically from a boat, and also attached to a long 'rod', such as a wooden pole, fishing rod, PVC plumbing pipe.
Use Google to find retailers of magnets specifically for magnet-fishing, usually they have loops/eyes for rope attachment. Search eBay etc, for similar. There may be a real physical retailer in your area .... in fact , Kellyco have a store in Casselberry, they sell the magnet fishing stuff.

[nickel_n]

try something like this with a long handle it cost few dollars in garden shops
you can see the use of it by fisherman on the middle of the page on the link i post

[Funfinder]

You must forget it, its not worth the effort.

But if you see it as some sort of gamble or challenge ...

1. Do you have placed a Buoy directly after the incident?

2. 4-15 ft ??? You need exact depth values first.

3. Forget the Neodyme - you'd need multiple of them attached to a board.

4. I would scare away the animals with some explosives and then go diving
with a very bright light if the sea is quiet and all is good visible under water.

5. Use some remote controlled underwater-toy to find this sunken over-water-toy.

6. Attach a mini-airbag for emergency-cases next time so the drone no longer sinks.

[kt315]

underwater tank project. https://www.youtube.com/watch?fbclid...ature=youtu.be

[MDfanatic]

Your best bet is fishing nets but again they can easily be torn apart by debris lying on the pond's bottom.
Unless you desperately need the footage, I wouldn't bother to retrieve it. The time and money you'll have to invest will be much more than the equipment itself, if anything can be salvaged at all.

If it's a long distance from where you live you should also consider the extra $$ on gas besides the equipment you will need to buy.

[godigit1]

I'm assuming the water is murky.

Make a long pole with a spring in the middle place a large coil on the bottom mount it on the kayak.

Either circle the shore at levels like you see on a topo map or probe it in sections. if you hit bottom your coil is relieved on the spring.
Also can be done with a magnet screen .
go to the local fabric store they have mesh type nylon that is much like a screen water should flow through it if you drag it slowly.
Then buy a magnetic brick they have 100 little 1/4 by 1/4 strong neo magnets.
Five minute epoxy to the screen in any pattern you want, the screen should be on a frame with just enough slack so the magnets cant touch but has some ply-ability so the magnets can conform to the shape of the drone. And now you have a magnetic drag net or a plungeable net you can make fairly large. hope fully there is enough exposed magnetic parts to pick up your drone by.
But if you hook a safe it will probably tear..

I feel your pain on the lost drone I've not been able to recover two f450's.

Good luck.

[godigit1]

216 magnets my bad.

https://www.lightinthebox.com/en/p/5...ountry_code=us