Homebuilt ROVs Forum

Hey Ole,

That's a good plan as he's farther along than I have gotten thus far.

I did finally get the ethernet comm working with the xbox controller, but it's still not as good as his stuff (YET!).

Can't wait to see what comes next!

Still working on a new prototype of the actuator. After a lot of thinking, I am now trying out a magnetic solution like sthone mentioned earlier. I already had the magnets and this approach should be more reliable and have less wear problems.

I also decided to go away from the oil filled electric compartments. At least for now. So what I have done is bought two water filter housings. I got the idea from "MR Fishing ROV" on youtube. After doing some research I found out that the "20inch big blue" type of housing will fit all my batteries and electronics. I could not find any source for these here in Norway so I had to order from the UK. I received it a couple of days ago and it's really solid! thick plastic, good seal and two 1" ports that will be used for thruhulls. These are rated for 9bar operating pressure, witch I believe is quite a bit on the safe side. While digging I found that the rated failure pressure (burst pressure) is around 30bar. Off course this is all pressure from the inside! situation will be different with pressure from the outside. This is the reason I asked about pre pressurizing the hull over at the "Frames, Hulls, & Bouyancy" part of the forum. I will ad a valve to allow for this. putting 5bar of pressure in the hull before diving should easily allow me to reach 100m ( 5bar of outside pressure actin on the hull) at least in theory

The smaller, clear filter housing will house my two ip cameras, one is wide angled and the other has a slight zoom on it to allow a more close up video feed of the manipulator. I will also have room for a gopro, lasers for measuring and a servo to tilt it all up and down.
This housing was much cheaper, but not as well built. A little reinforcing of the oring seal from the inside is needed.
The clear part is quite optically clear and I could see almost no distortion. The plastic it's made of scratches easily, but a replacement part is only $10 from the local hardware store.

This means that the old frame design is out the window and a new one needs to be made.

What are your thoughts?

Hi Ole,

Well, this is the definition of iteration isn't it?

That's one of the reasons I resisted all temptation to design my ROV before figuring out how all of the stuff works. I've been into this for over a year and have no idea what it's going to look like yet.

I see your point about the pressurized hull at sea level so you can go deep. It does work in theory, hope it does in practice.

I didn't read about Sthone's suggestion about magnetic actuators but I agree it's the way to go. I've done some work with magnets in my thruster and plan to use it for some 'thru hull' control of things.

Sounds like you have quite a plan for having lots of 'eyes' down there. I can't wait to see how it comes out!

Exiting day today.
Assembled and tested my second actuator prototype.
I moved up to M6 threaded rod and magnetic clutch.
The magnets I use measure Dia 8mm and 5mm length.

As shown in the youtube link below, I tested with 4 and 6 magnets. I didn't go any further since my scale was already over its capacity and quite frankly.. its more then enough force!

Very cool progress!!!

Looks awesome. I wish I could count on my 3D printer. It's been acting up for months now and I can't get more than a few good prints before it botches a few up. Very frustrating.

Keep up the good work!

Wow this just keeps on getting better.... that new clutch is amazing. I'm glad to see those magnets holding so well, it gives me hope that if I add a few more to my thruster design it may just work out like I planed.

I also need an actuator for TV stand project I have been designing and I thought I was going to have to spend a lot of money on one but after seeing this I realize now that I can just make my own so thank you for sharing your ideas. You guys really make this forum worth it.

-Steve

Thanks!
And thank you for the idea to use the magnets for this!
One thing I noticed quite early is how fast you loose the holding force of the magnets as you have them further away from each other.
On this setup they are only 1mm from each other. Before I started I didn't seat the magnets all the way in and there was noticeably less holding force in them. Just something to keep in mind

Again, not sure how reliable this will be over time. But I could see no sign of wear on the bushings or other parts after the testing.

It is a mighty force or what . Keep up the good work!

Progress day!

I made the new frame and camera housing today. I were planning on using the water filter as a camera housing, but that thing was just to bulky.

This is what I am working on now. Just so you get a general idea of how the layout will hopefully be. I used an old and tired lathe at work to turn down a lexan tube and end caps for it. The tube diameter is 70mm outside, 60mm inside and 200mm long.
The ends are made from black POM (Delrin). Machined to take 3 o-rings. The frame itself is made from one 1220mm x 610 x 12.7mm King Starboard plate XL plate. This XL version is actually a celular polymer plate. So this might have problems at depth/pressure. This was the only thing they had in the store and it was considerably cheaper then buying a solid POM or similar plate in the same size. I think it will be ok, but we will see

I made a drawing in Inventor of the frame and printed it out so that its shown as unfolded. Took 20xA4 sheets. I then taped them together and stuck them on the sheet of plastic.
This gave me clear lines where to drill, cut and bend. I then used a heat gun to heat the plastic and bend it over a 30mm steel pipe.

Finished frame. There is still a bottom frame missing. This will help align everything and correct the angles. Considering its done with a hacksaw and other hand tools I think it came out good. Needs cleaning!
Camera housing.
Where the WTC (big filterhousing with all electronics and batteries) will be mounted.