Not finished yet, but some modifications


#1

Hi guys

while assembling my Openrov I had to make some modifications: First one is a different endcap-design for the battery tubes. The acrylic parts for the endcaps were missing in my kit, so I decided to make new ones from plastic. Since my lathe was aleady running I also made some brackets for fixing the tubes. I was afread, that the strongs springs would reopen the tube, therefore I decided to make a version that could be screwed. I copied the orignal design for the o-rings but added a groove to put a second one that is sqeezed by srewing the endcap on. I Hope the pictures explain what I mean.

The other modification is concerning the tether. I purchased a cheap extension cord, took out the plugs and the cable an put the tether on the coil. The connection with the topside-adapter is made with a plug that rotates free. This whole setup is very compact and handy. again, see the pictures.

best regards from Switzeland.

Hub







#2

Awesome stuff! I dig the battery caps.


#3

Great idea.

How did you get the "bit the caps screw into" to fix to the battery tubes? Just epoxy them on?


#4

Yes, I sanded the outside and epoxied them on. We will see, how good it sticks. I have no idea, what happens, when this is exposed to pressure. I guess the nylon tubes will also be compressed a little bit by the water.
The pieces are made from urethane resin. I cast this in moulds. One could even make replicas of these in silicone moulds to make a small series. I could imagine to make something similar for the electronics tube with some sort of electric connectors for the wires already casted in. I will probably try that, once my Rov is operational. Right now I am trying to make it running.
Hub


#5

This looks awesome! Excited to hear how they perform.

Also, the tether management system is great. Well done!


#6

Some more changes: I do not have the recommended cement and had some doubts about how I glued in the syringe pieces.I could still see some air between them and th endcap. so I decided to replace them with some aluminum pieces. Then I had the idea, to find a way to add a second o-ring to the main tube, just like I did with th endcaps of the battery-tubes. I always had in mind to run a threaded axis through the whole tube in order to be able to press the endcaps together and by this applying force on the extra o-rings. So here is what I did: First I replaced the hinges for the camera-setup by tubes with a little flange. then I moved the servo out of the way and connected it with a steering rod to the camera-holder. then I threaded a stainless-steel rod and made one endcap bracket with a thread (where the rod will be glued in with epoxy) and the other bracket hasjust a normal hole. Then I took a rubber seal from a faucet and made a washer thta contains it and with this washer it can be pressed against the encap and the rod. I hope this seals the whole setup. Please see the pictures and tell me what you think abaout it.

now I move on and try to make the moters run correctly. I seem to have a problem there. If I can not solve that I will write in the electronics section.

Hub







#7

Hi guys

I just want to give an update on what I have been doing in the last couple of weeks.

After the redesign of the battery-endcaps I decided to take the same approach for the big endcaps. The acrylic ones were not really tight, because the grooves for the seals were to big. Since I didnt want to use any tape or other tricks that have been proposed here, I decided to make new endcaps from aluminum and use the same 2 o-ring approach. so one o-ring acts as in the original design, while the other one will be compressed by tightenig the endcaps with the bolts. The reason to take aluminum was because I had easier access, I trust more in endcaps from one piece (I still doubt how well the different layers of acrylic stick together) and also because aluminum is a better conductant for temperature. So here is how the endcaps look like. one with the o-rings in place, the other one still naked. It took quite some time to make them on my hobby-lathe, but would be an easy job for a cnc-machine (and probably cheep?)

I will do a series of posts to show the rest.

hub



#8

here is how I did the potting: instead of potting the original-cables I used insulated copper-wire and soldered the cables after potting. I assumed that the copper-wire bonds better to the potting resin and so might be tighter, also because no elastic material is between the copper and the resin. I was also able to put a couple of spare-cables through the same opening. of course the soldered wires on the outside needed to be insulated from water as well. I solved that by first using shrink-tubes and potting all the cables together and the end. I'l post pictures of that also.



#9

here is how one endcap takes the rod. The rod is screwed and epoxied into the endcap (m6 thread). the endcap with the wires has no thread but a smooth hole, that acts as a venting hole (you noticed: I don't have syringes in the endcap).




#10

Congratulations Hubertus:

Thats the kind of improvement, that from my point of view, makes a difference.

Regards


#11

some more pics, showing the new nut with o-ring seal and how its tightened with a wrench. If I do this, you can litterally see, how the outer o-ring of the endcap is compressed. this gives a super seal. so far, I could not observe any water between the outer and the inner (original) o-ring.

You will also notice my buoyancy-pods on the outside of the rov. this is to compensate for the extra weight. I made different pods to be able to trim even if I add other payloads (my next project is a grabber). these pods slide in brackets and can be moved forward and backward to trim.

the electronics-tube is fixed at the rov by the nut on the right side. you see the slot in the rov side, that takes the rod. on the other side there is a larger slot to take the entire nut. I secure that side with an o-ring.





#12

here the last pics of this series: my finished rov and how it fits in a plastic suit case.

now I am only waiting for better software to fix my bugs.




#13

Hi ¡¡

Are those buoyancy-pods empty ? Or have you filled them with anykind of foam ?

Regards