Variations on the OpenROV


#1

I'm interested in hearing about variations of the OpenROV design that people have built. Someone posted a picture of their quadracopter-inspired design, which was cool but I'm interested in hearing about other variations too.

I'm working on a ROV design using most of the same components (camera, electronics, motors), but uses a cylindrical, in-line design rather than the rectangular framework that OpenROV and many others use. i.e. the direction of travel will be along the axis of the pressure hull, not perpendicular to it. with the exception of the thrusters protrusions, the ROV will be 4 inches in diameter.

I'm going to try to keep it simple for now, but in the long run, I have a few interesting things I want to try:

  1. Sealed, pressure compensated thrusters - The idea of salt water in my motors just bugs me.
  2. Wireless communications between modules - I'd love to have an IR or low power radio link between modules so that there are fewer penetrations for wiring (or none). This would allow me to reconfigure the ROV quickly.

-BM


#2

I am also interested in using OpenROV components in a different configuration. On Cape Cod operation in seawater is a must, so I also worry about motor longevity.

Wireless communication between modules is a neat idea. Normal ranges for Bluetooth type signals through seawater is in the order of 1mm to 10mm. But some projects have allowed deep water communication between pressure housings by squashing a soft rubbery pad between glass housings. The pad excludes the water and leaves a channel that the RF can propagate through. If one used RTV adhesive to connect two plastic housings together the RTV would provide a similar RF conduit through the seawater.


#3

That's an awesome idea! This would be a great way to easily and simply establish comm between payload modules and the main electronics tube.

Keep the good ideas coming!

E


#4

I can't find my old post, so hopefully this will work. I got around to finishing my quadcopter inspired ROV.


#5

That's fantastic! Great use of an Otter Box! How's it perform?


#6

I'm debugging the software right now, but pretty nice. I'm not going to use the ESCs again though, as they are a hassle. And it's a bit much to cram in the Otterbox. It is pretty fast though. :D


#7

Looks like you have motors, right?

How do you control brushless motors without ESCs?

And what is an otter box? Looking online I only found iPhone protective cases, but that doesn't look like one :)


#8

I mean using different ESCs, sorry for the confusion.

I used these ESCs - http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14630

And this Otterbox - http://www.otterbox.com/OtterBox-3500-Clear/OTR3-3500S-01,default,pd.html?dwvar_OTR3-3500S-01_color=01&start=3&cgid=otterbox-3500-cases


#9

Sorry, I meant to ask: "Looks like you have eight motors, right?"

Those are the same ESCs I bought for my OpenROV: cheaper than the one suggested, and more features.


#10

Well update me if you ever get full speed reverse with those ESCs cause I have tried and been unsuccessful, only getting 50%. They also seem to forget their programming a lot too.


#11

Zachary: that looks awesome!

I actually though about a ROV that is inspired by the sub Virgin Oceanic is deploying:

The base would probably be something like an Otterbox as well. Not sure about how to have a camera fit somewhere. Maneuverability would be an issue too I suppose.

But first things first. A plain OpenROV is the first milestone.


#12

Took me a while to find where that question was asked :)

Got the motors and ESCs yesterday and looking through the ESC's manual I found the answer :)

It goes only 50% reverse because it's the default configuration of that ESC: you can program it via its programming card, or by listening to beeps and using a standard RC radio.

Here is a photo of the manual I found on the internet. It explains all the programmable options of the ESC.

HTH

Simone


#13

For the EZRUN-18A-SL, I use the settings (in the format of "Setting (Value)":

1(3)
2(8)

6(4)

And I leave all other values to default.

I've noticed that the motors (ultimately the ESC's) tend to pulse on and off at full throttle when the batteries are getting low, so I may also experiment with changing setting 7 to (1) or (3).


#14

In addition to mode programming, it may be possible to replace the firmware on that ESC by reprogramming the micro.


#15

I'm getting very tempted to go with the same Otterbox drybox as an enclosure, at least for initial experiments.

Could I ask what you went with to feed wiring through it?


#16

A PVC cap thing, a coffee can lid, and a ton of wires, and silicone like adhesive. I cut the outside diameter of the coffee can lid to the PVC cap's inner diameter. I printed a template with 54 holes in it and taped that onto the coffee can lid. I drilled the holes with a hand drill. Then I glued the lid into the cap and let it dry. Then I fed the wires through the holes 1 by 1 and dabbed them with super glue to hold them in place. Then I filled the area with the silicone adhesive and let it dry. I cut a hole into the Otterbox with a Dremel and put the cap into the hole. I stuck an O-ring on it and tightened it down with the tightening nut. After testing this it leaked so I decided that the tether will not be removable and just siliconed the cap on the inside. It worked.

I wish I could describe the cap more but currently I do not have the ROV. I can take pics of it tomorrow however, if you like.