Any suggestions on my ROV design?

[rovebuilderguy]

Hi, I'm new here. I'm working on a freshwater ROV and would like some feedback on my rov design. I am working on this with no budget at all, so I have to use what I have around already. So here it is. I'm using four peanut butter jars, a rack from an old grill, six non-sealed brushless 12v DC computer fans for propulsion, a 50 ft. extension cord + a cat5 cable for power and control and video, a digital camera with NTSC output, an LED light array, and two plastic containers with lead weights for buoyancy control.

I will attach a picture to give an idea of what it would look like. I set all the parts together just to see how it would work.

One of the things I am wondering about is the position of the motors. Does it look like it would work? Or do they need to be mounted on the sides so they are more out in the open with no obstructions in front or behind them? Has anybody else used computer fan motors?

I didn't plan to use relays. I am guessing that the fan motors won't take much power and I can just power them through the cat5 cable (using one wire of the extension cord for common ground). Or are the cat5 wires too small to handle the power?

Any thoughts or suggestions would be appreciated.

Thanks,
Shawn

[Aquaticfox]

Your design looks nice, I like the PC fans "Never would of thought of that" Anyway your R.O.V. design and thruster position look good. It looks as though it would corner well "depending on the power of the fans" Your idea on using relays is fine, however I would use three way toggle switches that way you can have 2 thrusters "one from each side on opposite corners" turning clockwise and 2 other thrusters "one from each side and on other opposite sides" running counterclockwise this way use can get "much" better mobility. Also another thing, those jars look very fragile so be careful when your piloting it through the water. *Note* my R.O.V's are still in schematics so you might want to take advice from someone with more experience than from me. Again though, I like the layout of your design.

[KR2_Diving]

Great design!! I like the ingenuity and using parts that may not be "standard" parts! In my opinion, this is EXACTLY what a Homebuilt ROV should look like! Well done!

If i understand your comments correctly, you are planning on running power down the 50ft extension cord, splitting it to the relays, and controlling the relays from the surface via the Cat5 cable... I think with only a 50ft cable you might just get away with that!

Best of luck!

Ryan
"KR2_Diving"

[Silver dollar]

Nice design! But I suggest you to turn the jars 90 degress and put them on both sides of the motors. This to be more stream lined.

[fluxno]

have you tried the computer fans in water?(in a sink,bucket, bathtub or similar?) I cant remember if i read about another user on this forum or on openrov.com forum that had tried using computer fans.
his experience was that the fans almost completely stopped when entering the water because of the drag.

[Alaska Rov Systems]

Just to let you know, computer fans will eventually short out due to electrolysis. The Rov would need to be in deionized water. Nice design but i would go with bilge pumps which are designed for underwater use.

Alaska ROV Systems

[rovebuilderguy]

I'm finally getting back to the forum to reply to the comments. Sorry it has taken awhile.
Hey thanks everybody for the comments and ideas!
I have tried the computer fans in a bucket of water. On further testing I don't think they will work. The drag is too much for them.
So I got some motors out of an old printer I will try instead.
I would like to turn the jars 90 degrees, but the ends of the jars are not clear enough for the camera to see through unfortunately.

I'd like to use bilge pumps, but yeah, right now I can't afford to spend any money on my hobby. So I have to see what else I can do.

So I suppose electrolysis will affect any electrical contacts that are exposed to the water? How long will it take for the motors to die - like 1 hour of use, or 100 hours of use?

Thanks again to everybody for the suggestions!