NATALUS - ROV

[Jaman42]

Hi guys, I have been planning on and off for quite some time now. The project got delayed a bit when life got in the way (literately, when my second born son arrived), but now I am back on track again. I will do my best to have it ready before summer. I thought I start a build thread to help push things forward since I got most of the materials I need and I am in the stage to start assembling. It might take a while thou since I lack most of the machinery I need and have to rely on people in the vicinity lending me their tools . For the aluminum parts I actually bought a fairly big lathe that I kept in a rented place, when I was done with the parts I resold the lathe again. I might have to do the same with other tools since I still live in an apartment and don't really have the room for it.

The name is a mix of my partners name Nathalie and the fictive submarine Nautilus from the movie "20,000 Leagues Under the Sea".

I plan to add some sort of gripper arm, I also had a thought of having a electromagnet. I am going to control it with a PS4 controller, one topside and one bottom side Arduino as the brains. I am using a CCTV camera as live feed and plan to have a Gopro for recording. The communication between the Arduinos is RS485 over fiber optics which also carries the video feed. The power source is planned to consist of 8 pieces of 5000mAh 4S 20C Lipo packs.

I include a drawing and a render to give you the general idea of how the ROV will look like. Some parts are just made to hold other parts at place and will not necessarily look that way when finished. The connections for example will be molded and I plan on having jointed holders for the lights to be able to adjust them easily. I also plan on having a tilt able camera but I haven't made any plans on how that will look and work yet. I just started drawing the wiring but I am not sure if I will continue doing to much work with the 3d-model of the ROV. It's time to start building it IRL instead.

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Here are some of the machined aluminum parts I have made, they need some welding which is going to be the next step:

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Thanks for reading, building a ROV would be so much harder without all the ideas and guidance from all the people here on the forums.

[Jaman42]

Long time since last post, been busy I guess and not getting to much done with the project. My goal of finishing this summer seems tough but perhaps not completely impossible.

I couldn't get my hands on a TIG welder so I decided to try some aluminum brazing instead. The process is pretty simple, first make sure you clean and then rough up the surfaces, I used a 80 grit sandpaper. Next it is time to get the material up to heat and then melt the brazing rod by applying it against the joint of the materials. Then make sure you have something to scratch with like a flat head screwdriver, then you scratch in the joint to brake the aluminum oxide layer that forms when aluminum is exposed to oxygen. Since the joint is covered with aluminum brazing material it isn't exposed to any more oxygen and the brazing material will stick firmly. So all you need is a torch, a screwdriver, sandpaper and some aluminum brazing rods.

I only had a couple of small torches so I was having a bit of a hard time getting the material up to the correct temperature, the next time I will use a bigger torch. During the process I realized how important it is to try and put the material on something that doesn't absorb to much of the heat. I didn't manage to get good looking joints but didn't worry to much since I was planning on painting the parts anyways.

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Next I started sanding and smoothing out the joints, then I applied a layer of JB weld to them. The idea was to get them smoother and to fill any possible hollows.

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Once the JB Weld had dried I started sanding the surfaces again, preparing them for the paint. I didn't have access to anywhere I could use a spray paint so I had to manage it with a brush. I started with a layer of epoxi primer, then some sanding, then another layer of primer and some more sanding, then another layer of primer........ and so on.

Then I applied a layer off a polyurethane coating, then some more sanding, then another layer and some more sanding.......and so on. Overall I am very pleased with how the parts turned out, I haven't taken any pictures yet but I will try to post some later during the day.

So now it's on to the next row in the list of thing I need to get done, thanks for reading.

[sthone]

Very cool.. and nice progress. What are you planning on using for thrusters? (just guess form the rendering but Blue robotics maybe?)

-Steve

[Jaman42]

Thank you, yes I was planning on using blue robotics from the beginning. With shipping and taxes I thought it became a bit to expensive. A few weeks after I ordered parts for making my own thrusters Blue robotics revealed a couple of European re-sellers so that was a bummer.

So I am planning on rolling my own Blue robotics thrusters, some of the parts will be identical, some of the parts will actually be Blue robotics, and some will be custom. If it comes together as well as it does in my head that is, we'll see.

I took a couple of pictures of the painted parts, i left an area on the bottom of the containers unpainted where I will attach a sacrificial anode. I left the rings to the camera and lights unpainted for the looks.

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[Jaman42]

I cut out the parts for the main frame from 10mm HDPE board. I also plan on making some mounts for the WTCs with the leftovers. I am going to assemble the frame with bolts and nuts, I was thinking of welding it together but I decided that I would like to keep the ability to disassemble it.

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[Jaman42]

So I started putting the frame together, I have a bit of work left but it's nice to see some progress at last. I was surprised how strong the screws held on to the HDPE board. I had plans of using glue as well but now I found out there is no need for it.

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[SSN626B]

@Jaman42,
I used 10-24 stainless steel flat head screws, instead of the more common 10-32 screws, to hold the chassis 1/2 inch thick HDPE sides to the chassis center section. The 10-24 screws make a very solid connection.
Regards,
SSN626B/TCIII

[Jaman42]

Finally I got some time to make some more progress on the ROV. I'm working on the wiring at the moment, I got it all laid out and I am almost finished preparing the wires to be able to cast the hull penetrators with epoxy.

I have waterproofed a optical fiber connection that I was a bit worried about. I used two duplex cables, then I joined them with FC-FC adapters. My system only uses one cable but I thought I might as well use a duplex for the penetration to have a spare just in case something goes wrong. At the connector I stripped the cable down to the core. Then I Filled that empty space with EPO-TEK 353ND, it's a heat cured epoxy specially made for fiber optics. I will then cast the whole connection in a hull penetrator, with adapter and connectors. After the heat cure I thought the inside cable felt a bit sloppy so I thought I might have ruined it. I did a test run yesterday with the prepared cables and they booth work, pheeeew.

Even thou I am using fiber optics I am also gonna make sure to have 4 twisted pairs unused to have some options in the future. Today I plan on getting the last bits ready to be able to start casting in the weekend.

It's a bit of a mess at the moment but I am getting there

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[Jaman42]

Now I am done casting all the hull penetrators, I had to do some of them more than once because I thought it was that much fun, or was it because I rushed it and didn't made sure there was a good connection on all the wires and that nothing was short circuiting, never mind it was one or the other. I used an epoxy called NM El Epoxi 960 which is especially made for casting and waterproofing electronics.

I have done all the wiring for the power supplies and just started with the sensors and other electronic components and will continue to install them and writing code.

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[Jaman42]

My first try with the internal electronics didn't end very well. Everything was working but I got some disturbance in a couple of wires and it got really messy so I decided to redo it from scratch using a couple of breadboards to keep things more organised.

Here's the mess!

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I also decided to redo my penetrators, I had some issues with loose wires due to handling before they where epoxied so I took a different approach to try and solve that. It took a while to clean up all the aluminium parts getting rid of all the epoxy. I am using 3mm copper rod for the high amp penetrators and brass of different diameters for the low current stuff. I flatten the ends of the pins to be able to drill a hole for the wire that is soldered in place. It feels more robost so I don't think I will have any more problems with loose wires. I also took a different approach trying to integrate more connectors instead of just running fixed wires to be able to detach and modify more easily.

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I also tried to integrate the components in a more space efficient way

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During my first epoxy session I hade some issues with epoxy finding its way thru incredible small cracks. In some places it even went about 10cm up the cable jacket resulting in leaks in some places and very stiff cables on others. I tried to solve this by first filling the penetrators slightly with a thicker epoxy, after cure I filled the rest up with the other epoxy. Out of 14 penetrators I had one slight leak on 1 penetrator so it went much smoother this time.

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I will finish all the penetrators to the main WTC first then I will upload some pictures of the new and improved (not as messy) internal electronics