Re: A 3D printed, raspberry-brained ROV project
Posted: May 25th, 2021, 5:51 pm
Hi!
A few weeks have passed since my last post, and many things have changed this then! Not for the best at first, as I've had some disappointments with the original hull design that led me to revamp most of it. To the extent that I had to update this thread's name, because fiberglass & epoxy won't be used anymore. But it is going to save me from a lot of additional uncertainties and difficulties in the future.
Here's the full story: I tested the assembly with the parts that were already printed in a basin to test the joint between the upper and lower hulls. It happened to be a disaster. No way to prevent water from flooding in at an observable rate even with screws fully tightened. FYI, screws were placed roughly 4-5 cm away from each other.
In the meantime, I made a new plexiglas forming attempt with a positive mold and a vaccum cleaner, as I saw somewhere on the web. I pressed a square of plexiglas maintained within a wooden frame against the mold, on which I drilled small holes that were connected to the VC. But a 4mm-thick layer of plexiglas is not something easy to bend, and it did not even came close to fit on the surface of the mold. Furthermore, as predictable, I faced a problem of punching on the center of the layer, that was pressed against the top of the mold. The constraints being concentrated on that small area, had a terrible result on the transparency of the glass there.
Anyway - back to basics! As anticipated earlier, I'm falling back to using a good old PVC tube, that will be much easier to work with, especially regarding the watertight joint. For the front glass, now that i have a perfectly round shape, I will simply use an acrylic dome like this one found on Amazon:
This is a cheap CCTV protection, but thick enough to adapt to a ROV. I think it would also be good to design some sort of bumper that would protect it from scratches.
I'm still using a 3D printed hull, though. I designed a new one that will surround the WTC. But since it won't hold the pressure (it will be flooded with water), fiberglass won't be necessary anymore.
Here's the new look:
I was recently searching for devices that would help connecting wires underwater, especially the ethernet cable and the control and power wires of the gripper (TBD) to the container. What would you guys recommend?
A few weeks have passed since my last post, and many things have changed this then! Not for the best at first, as I've had some disappointments with the original hull design that led me to revamp most of it. To the extent that I had to update this thread's name, because fiberglass & epoxy won't be used anymore. But it is going to save me from a lot of additional uncertainties and difficulties in the future.
Here's the full story: I tested the assembly with the parts that were already printed in a basin to test the joint between the upper and lower hulls. It happened to be a disaster. No way to prevent water from flooding in at an observable rate even with screws fully tightened. FYI, screws were placed roughly 4-5 cm away from each other.
In the meantime, I made a new plexiglas forming attempt with a positive mold and a vaccum cleaner, as I saw somewhere on the web. I pressed a square of plexiglas maintained within a wooden frame against the mold, on which I drilled small holes that were connected to the VC. But a 4mm-thick layer of plexiglas is not something easy to bend, and it did not even came close to fit on the surface of the mold. Furthermore, as predictable, I faced a problem of punching on the center of the layer, that was pressed against the top of the mold. The constraints being concentrated on that small area, had a terrible result on the transparency of the glass there.
Anyway - back to basics! As anticipated earlier, I'm falling back to using a good old PVC tube, that will be much easier to work with, especially regarding the watertight joint. For the front glass, now that i have a perfectly round shape, I will simply use an acrylic dome like this one found on Amazon:
This is a cheap CCTV protection, but thick enough to adapt to a ROV. I think it would also be good to design some sort of bumper that would protect it from scratches.
I'm still using a 3D printed hull, though. I designed a new one that will surround the WTC. But since it won't hold the pressure (it will be flooded with water), fiberglass won't be necessary anymore.
Here's the new look:
I was recently searching for devices that would help connecting wires underwater, especially the ethernet cable and the control and power wires of the gripper (TBD) to the container. What would you guys recommend?