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Hon1nbo

Sun Apr 04 2010, 03:59PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

aonomus wrote ...

The blue-pink indicator is CoCl2, the problem is that its not benign (actually toxic and carcinogenic); I wouldn't be happy if I released some into the environment by a leaky ROV pod. The hardware store stuff should be plain old CaCl2 desiccant, just ask for some desiccant and they should have it.

In regards to the battery/weight issue, its up to you ultimately what 'system' you want to design and what works for you. If you have money to spend I would recommend using 'Bulgin buccaneer' connectors; they are quite spendy, but other home made ROVs have had success with these.

I have considered building an ROV before but never had the inclination to nor the cash, hopefully I can give at least one idea that helps :)

I didn't realize the indicator was toxic, I'll look into the alternatives - but then again, this is only for the small sealed compartments but a hazard is a hazard

as for the Buccaneer Connectors, they were recommended to me in another thread (waterproof USB connectors) but they are expensive in the multi-pin designs that do not use computer connectors. I have four Bilge Pumps, a Ballast Valve, the camera/light connections (which use Ethernet), and the Fiber Optic Link - I plan to just give each of these three categories a separate Compression Fitting which makes a seal equivalent to cemented PVC, and use a piece of PVC pipe with the wires sealed inside as the "plug" that goes into the compression "socket" - I plan to keep this ROV for years at my farm (we have tanks with fish) and on some dives in various places, so upgrades will likely come after the grade is received from the school

as for the cost, I was helped a lot by some local stores. The local boat shop was willing to sell me the bilge pumps at the price they receive them at (e.g., they were only costing the minimum to not lose money giving them to me) because it was a school project. I am building almost everything from low cost components that I do not already own, and the fancier things (like the fiver optic media converters) are only being used because I already own a set I picked up at a Ham Fest

Never assume a project is out of your range, there is always a way if you take the time to work with what you have

-Jimmy

aonomus

Sun Apr 04 2010, 05:49PM

Registered Member #1497 Joined: Thu May 22 2008, 05:24AM
Location: Toronto, Ontario, Canada
Posts: 801

The cost factor on my part was mostly not wanting to spend money that I don't have, no job and student loans to pay off tends to do that... The big cost for me was a video camera.

Good luck on your project, I'm cheering you on from the sidelines.

Hon1nbo

Wed Apr 14 2010, 01:51AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

A quick update:
I had an interesting find at my local Lowes hardware store: Waterproof Electrical Connectors made by Cooper Wiring Devices, rubber molded male and female ready to be spliced onto a cable and so far they have fared well in my pool for submersion testing (it is getting late here, so I'll make one more check in half an hour then wait till morning light and see how it went)
the pair of the two comes to about $26, but they fit perfectly onto the end of a common orange extension cord so even if I do not use it as the primary connection in this sub, I definitely will be using it for the "accessory" port I am going to have in case I want to have something like a claw or a toy torpedo add-on lol, also I will be using them on my normal extension cords to make the "outdoor dry" cords suitable in water environments (e.g: no short out if the cord is left in the rain etc) - I bought one for now, but the hardware store had loads of them.

I mounted the 1/8 inch Lexan sheet as the component bed using a lot of Zip-Ties (The zip ties do not bear weight, they just work with alignment issues and sliding).

I attached the 500GPH turn bilge pumps to the Lexan, and did a basic water test and they are moving the frame! - not the fastest thing in the world, but even after factoring in the mass of the full unit it should be plenty to turn the unit

I had some problems with my Bilge Pump drive circuit, I am going to resort to bread boards to diagnose the potential problem, which is likely associated with my blocking diodes leaking current or my transistors picking up induced voltage on their gates - I think I'm going to try the same optoisolators as my control panel Matrix uses, as they should be able to handle the current of the bilge pump motors (2.5 Amps for each fuse).

I haven't had luck finding someone to splice my fiber optic cable for me, and I don't want to hire a pro-company to do it because I'm not going to pay $$$ for splicing one end of one cable! - because the cable is non-electric, I may just cut lengthwise down the vinyl tubing sheath and fit it in, then close it every couple of feet to prevent it from coming out.

-Jimmy

Steve Conner

Wed Apr 14 2010, 11:41AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Splicing fiber optic is tricky. Well, it's easy in one sense, you prepare it with a cleaver and then pop the ends into an automated splicing machine, which fuses them with a tiny electric arc using precision servos under control of machine vision. It's getting access to this expensive precision equipment (and someone who knows how to work it) that's the tricky part.

If anyone can do it, your local cable TV, telco, university optics lab, or computer networking contractor can. My old workplace had the gear, and I learnt to do basic splices, but I wasn't an expert.

Also, it's fragile stuff, so I wouldn't trust vinyl tubing to protect it: vinyl stretches, glass doesn't. But as far as I know optical fiber is waterproof.

In one project I was involved with, we used a special cable that contained 2 fibers, 4 copper wires and a Kevlar strength member to protect the fibers. It was designed for carrying multichannel audio in outside broadcasts. Neutrik made connectors for it.

I'd ziptie or tape the optical fiber to some thin wire rope, nylon cord, copper wire, anything that won't stretch.

Hon1nbo

Wed Apr 14 2010, 01:13PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

Steve McConner wrote ...

Splicing fiber optic is tricky. Well, it's easy in one sense, you prepare it with a cleaver and then pop the ends into an automated splicing machine, which fuses them with a tiny electric arc using precision servos under control of machine vision. It's getting access to this expensive precision equipment (and someone who knows how to work it) that's the tricky part.

If anyone can do it, your local cable TV, telco, university optics lab, or computer networking contractor can. My old workplace had the gear, and I learnt to do basic splices, but I wasn't an expert.

Also, it's fragile stuff, so I wouldn't trust vinyl tubing to protect it: vinyl stretches, glass doesn't. But as far as I know optical fiber is waterproof.

In one project I was involved with, we used a special cable that contained 2 fibers, 4 copper wires and a Kevlar strength member to protect the fibers. It was designed for carrying multichannel audio in outside broadcasts. Neutrik made connectors for it.

I'd ziptie or tape the optical fiber to some thin wire rope, nylon cord, copper wire, anything that won't stretch.

I might check the local universities (SMU probably can help me, and I am an admitted student with honors lol)

as for the tubing issue, I know fiber optic cable is waterproof, the tubing will only be there to add support and the prevent tearing should the cable get caught on something, but I might try a rope

-Jimmy

klugesmith

Wed Apr 14 2010, 08:02PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

DaJJHman wrote ...
...I haven't had luck finding someone to splice my fiber optic cable for me, and I don't want to hire a pro-company to do it because I'm not going to pay $$$ for splicing one end of one cable!

Hi Jimmy.
Steve talked about the high-tech tools for making a fusion splice between two raw fiber ends.
It takes a lot less gear to terminate a raw fiber into a connector.
Assuming your starting point is a cable with connector on each end -- can you cut off one connector, fish the cable through your umbilical hose, then put on a brand new connector?

Here is one of many videos showing termination of a fiber into SC connector.

I think in a pinch you can find a tolerable substitute for the fancy polishing films. How many gigabaud * kilometers do you need to reach?

Looks like putting TOSLINK or Agilent connectors on consumer-audio fiber could be easier, maybe tool-free.

They carry pre-made Toslink cables up to 30 meters long. I'm unfamiliar with the optical loss budget in plastic fiber systems. Have noted that most Toslink Rx modules have a minimum frequency limit -- no good at DC.

Hon1nbo

Wed Apr 14 2010, 08:42PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

Klugesmith wrote ...

Here is one of many videos showing termination of a fiber into SC connector.

I thought all fiber connections not factory made had to be done with skill, all I need to do is put on a new connector on one end. I could do that I guess, at least for the first time around.

I have about 100 feet of cable at the moment, though my goal in the future is to have up to a mile of the current type of SC cable (multimode) then if it works well enough possibly upgrade to single mode and get longer distances

Also, with toslink I would have to then make custom adapters for my two Fiber Media Converters that I already have

-Jimmy

Steve Conner

Thu Apr 15 2010, 10:53AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Klugesmith wrote ...

I'm unfamiliar with the optical loss budget in plastic fiber systems.

It's not good! Toslink-style plastic fibers are made out of PMMA (same stuff as plexiglass) and not really usable beyond 10 meters. The attenuation is something like 150dB/km.

Hon1nbo

Sat Apr 17 2010, 07:45PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

I updated the main post with pictures and some new status of the build

-Jimmy

Hon1nbo

Mon Apr 19 2010, 08:34PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

main post updated with some more pics.

I 80 feet of Vinyl tubing for the fiber cable, I sliced down it lengthwise, and fit in the cable. I then drilled a hole in a PVC end cap, fed the cable/tubing through, and filled the entire cap with Silicone. I also used some tape and hose clamps up the length of the tubing to help make sure that it doesn't pop out (the tape will be replaced with zip ties soon, I couldn't find them when I needed them). Only the end of the cable is sealed, as that is all that is needed.

and I may have gotten a big break: a local dive shop said they might be able to sponsor some BCD (Buoyancy Control Device) hardware, which would be very easy to control using smaller hardware and work very well! - no need to mess with the complicated paintball gun, check valves, plumbing, etc!

-Jimmy

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