First Dive Success... at first


#1

Last weekend I took my newly completed ROV for its very first test at my relative's pool. I had told them about my "underwater robot", but they were not sure what to expect. Based on their reactions, I could tell there were very eager to see it in action.

At first my ROV would not connect to my computer. I spent a long time looking over everything and taking things apart to find that the problem was an oversight of forgetting to plug in the wires to the home-plug adapter.

Now, I could finally test my ROV. This was either a sink or swim situation. If it sunk I would have lost all the hard work I had put into it and if it stayed afloat I would have the satisfaction of a job well done.

I slowly lowered my ROV into the water. My grandparents took out their cameras and waited anxiously. The moment could have not been any more suspenseful. I could only think that the moment I placed it in the pool, water was burst in and swallow my helpless ROV. However, this was not what happened. IT FLOATED!!! I was extremely glad that it worked and my family cheered. I drove it around and that also worked. Although it was hard to drive. This was either, because only some of the ESCs were successfully programmed or the motors were connected wrong, but it still WORKED!!! I drove it around a little longer, until something terribly wrong happened.

The motors became slow and eventually stopped responding. My ROV slowly sunk. I looked on my screen and I lost connection to my camera. In a frantic, I looked at my submerged ROV and saw it's dying heartbeat. The lights on the home-plug adapter and BBB slowly flickered out. My worst fear had come true. I quickly pulled it out of the water and inspected the ROV for water-damage.

Since it was late at night, I only saw some mist in the tube. I was confused how this could have caused the problem, until I saw about 3 inches of water at the bottom. I opened it up and water gushed out.

I immediately jumped into action and felt like I was part of emergency response. I dried everything off. I believe the problem originated from the syringes, but I am not sure.

All in all, I learned a lot that night like paying close attention to detail. Now I have a chance to go back and make my ROV more robust and a more secure machine. Surprisingly, the only thing that I believe does not work is the controller board everything else seems to be working. I am going to do more tests on my parts and waterproofing the enclosure. I have a lot to do so I am going to get started.

Thanks

Dive footage (I have to figure out how to save footage from the ROV, so I recorded on the surface)

After early tests earlier today


Photo from completed project



#2

Congratulation on your build, as you have found out everything we do in life seems to have a learning curve and never goes as planned. I am sure you will get everything back up and running and have lots of fun and enjoy some exploration.


#3

Hey Sam,

To echo David Murphy- congratulations on your first water test! Sorry to hear it ended up with some problems, but hopefully you can get her up and running for another test soon! Have you gathered any more information about where the leak may have happened? Since it sounds like it started sinking all of a sudden, I wonder if one of the endcaps popped out slightly while you were driving. That's happened to me a few times, and I'm trying to figure out a good way to get the endcaps to stay on more securely.

I've been meaning to write down the steps I usually take when something floods, so I figured this would be a great place to do it!

These steps should be done as soon after the flooding event as possible:

1: Turn off power to ROV right away (this will keep electrolysis from corroding the electronics)

2: Dump out the flooded water. If only some of the electronics have gotten wet from the flooding, try to avoid getting "dry" parts of the electronics wet while dumping

3. If the water that flooded the tube was not fresh water, rinse the electronics that got wet in fresh (preferably distilled or even better, de-ionized) water to dilute and remove the minerals from the area that got flooded (salt and other substances in non-fresh water are what generally create the electrical path that damages electronics that get wet). Sometime the best way to do this is to fill a small tub with fresh water and dunk the electronics in the tub, then stir them around to make sure water is moving in and out of the affected areas. You're goal is to replace flooded water with fresh water

4. Take the electronics apart to expose as many surfaces as possible

5. Rinse the affected areas one more time with fresh water now that the boards are apart

6. Wash away the fresh water with isopropyl alcohol or ethanol. This will remove the reminiscence of fresh water (which by now will have absorbed whatever was in the water that flooded the tube), and the alcohol will evaporate away quickly. If you don't have a container of cleaning alcohol, alcohol whips can be used to wipe down the rinsed areas instead. I wouldn't recommend using drinking alcohol as it will likely leave a residue from the other things it has, however I haven't really tried this out to know for sure.

5. Thoroughly dry each of the pieces of electronics. Compressed air can be used to help dry out female headers and other places that don't get much natural air flow.

6. Put all the affected electronics in a dry place. I like to use zip log bags filled with rice.

7. When you re-assemble everything, inspect for corrosion. If you see any, it can often be removed with a tooth brush so you can see the extent of the damage beneath it. Corrosion doesn't necessarily mean failure, but it's good to remove what you can. I also recommend wiping down non-electronic parts that are normally dry but got flooded, as they may still have mineral residue which could mix with fresh water that accumulates from condensation in the tube.

Okay- please keep us posted on you're developments. You're a great story teller!

Eric


#4

Thanks Eric and David and thanks for all the information, it helps a lot. Would these steps still work if I did them now? I am not sure where the leak is coming from, but I will keep you posted on further tests.


#5

Congratulations on your first test dive! I'm hoping to have one soon too.

I too have noticed that my wire bundle seems to be responsible for pushing out on the end cap on that side. When I first assembled everything the end cap was sung, then half an hour later it had slid out quite a bit.

I've started flipping the outer 'rubber band' off the edge of the electronics tube so that it pushes the end caps inwards. The orings that pull the electronics tube into the main chassie are what I call, "rubber bands." There are two passes on each side, the outer pass is the one I slide over the edge of the tube.