Changes on #241


#1

History of OpenROV #241 which I started in Dec. of 2012.
I did not buy a kit but have had a great time building it in my shop.
Most of the changes:
1. replaced the Plexiglas shell with an aluminum shell with holes every inch
I was always attaching stuff and found it hard to do with the Plexiglas.
2. added a GoPro camera, the mount I 3D printed with a MakerBot.
3. Props: I started with the original plastic fan props, changed to brass props and
now am using the Graupner plastic props. These made a big difference! All my
props have been installed with a metal hub and set screws which make it easy
to change and disassemble. All so they don't come off.
4. moved my motors to the outside of the shell and printed the motor housings
using a 3D printer. I have changed the motor housing 3 times trying to get
better flow.
5. Because I keep adding stuff I have tried several things to balance the weight.
At first a small inner tube on the top, then ping pong balls held by a housing 3D
printed, and now fishing floats attached with clips. These are easy to change to
make adjustments.
6. The battery tubes are held in place by some plastic clips that were 3D printed
which I found on the Thinkiverse website. I have always used o'rings on the ends
of the battery tubes and are my own design. My batteries are hooked in series.
7. With the release of the 2.5 build, I changed the electronics to the new controller
and IMU module. My electronics housing uses one o'ring on the port side. The
other side I cut a tight fitting Plexiglas end and glued it in. I am using a thicker
o'ring then in the parts list and have not had trouble with leaking.
I have only been down to 35 feet, so I might leak at deeper depths.
The new 2.5 design allows the camera to rotate up and down.
8. I have been using 1/8 inch brass pipe plugs in the ends of the electronic tube,
In place of the 1mL Syringe for End Cap venting. These are easy to put in and
out for assembly and allow me to attach the Mityvac test tool to check the vacuum.
It also helps pull in the one free end with the oring on it when you pull a vacuum.
I usually test with 10 inches and it holds for several min.
9. After 20 or so dives my motor bearings failed and I replaced them with
ceramic bearings from Boca Bearings.
10. If you look close at the attached pictures you will see I have connectors on the
motors, the IMU, and the battery tubes. I have had this apart a lot. I have
never been in salt water and my connectors are not water tight.
11. I have tried 5 different tethers. My current one has 200 ft. of wire in a plastic
tube so it floats. I have been mostly in ponds which have lots of weeds and my
tether was always getting stuck. I am using a cable winding device I got from
Tractor Supply. I have a connector on this cable so I can detach it from the
unit to make it easier to work on.
12. added red laser diodes with the 2.5 change.
13. This weekend I added the green cones on the ends of the battery tubes which I
drew up in Inventor and 3D printed with the MakerBot.
14. I am currently using the 2.5 image software. All of these changes have been
listed in this form with more information.

John

858-frontview.jpg (238 KB) 859-portmotorhousing.jpg (278 KB) 860-sideview.jpg (205 KB)

#2

Those are some pretty awesome mods.

What 3d printer are you using?

Do those battery cap cones seal the tubes, or just cover them?

How much was the new floating tether?

Cheers!


#3

I am using a MakerBot 2x with ABS material. The heated base makes a big difference.

I have also used a MakerBot 2 with PLA and it is not nearly as good.

The battery caps fit over the tubes. I posted images and the drawing with dimensions a couple of days ago.

The floating tether is covered in a post on June 24.

John


#4

I love seeing all of these mods! This makes me realize I really need a 3D printer.

When you made the aluminum shell did you use CNC devices (I assume you did because the holes look very uniform)?


#5

Yes, I used a ShopBot.

John

861-framealum1.jpg (130 KB) 862-framealummachining.jpg (168 KB)