Planning Submersible ROV

Hi guys, got a few more questions regarding the Submersible ROV I am currently planning on building.

Basically, I'm just wondering if this is the correct setup for what I am planning. I want the control unit to have video feed displayed on a LCD and a Xbox 360 USB controller plus switches to turn LED lights on/off.

My idea is to have an arduino on board of the sub controlling the thrusters and lights. An arduino in the control unit on land would receive input from the xbox pad and switches then send commands to the one onboard. I am using a raspberry pi to display the video feed on the display, and I am also toying with the idea of a python GUI to display the video feed and maybe interact with the sub. I know that i will need to communicate over rs232/422 to reach the tether length I want, with that in mind would the raspberry pi be able to replace the arduino in the control unit and communicate and control the arduino on board?? Would there be any speed decrease?? Or should I stick to an arduino in the control unit with the raspberry interacting with that one

Another idea i was thinking about was some sort of hud on screen, and one of the bits of information I would like on screen was depth the sub was at. I cant seem to find a sensor module for this and I dont know if one exists, but if not would it be feasible to use a water pressure sensor from say a central heating unit with the arduino and work out the depth from the reading from that?? Something like This

Thanks in advance

There are many pressure sensors that are suitable, that cheap unit may be suitable but check its construction , Is it suitable for salt water if you intend to use it at sea.

Have you considered where you will get the cable from ? For depth it will not be cheap, neither will the glands be . What cable type ? Obviously it will need something capable of carrying video.

Ethernet springs to mind a suitable for everything provided you an get the cable. Plus conductors for power supply as well, which will need high voltage insulation if not battery powered (noted elsewhere).

Boardburner2: There are many pressure sensors that are suitable, that cheap unit may be suitable but check its construction , Is it suitable for salt water if you intend to use it at sea.

Have you considered where you will get the cable from ? For depth it will not be cheap, neither will the glands be . What cable type ? Obviously it will need something capable of carrying video.

Ethernet springs to mind a suitable for everything provided you an get the cable. Plus conductors for power supply as well, which will need high voltage insulation if not battery powered (noted elsewhere).

Cheers for the reply.

I have a full box 300+M of cat5 cable so i was intending on using, just hadnt investigated if it was suitable to run video and communication down the same one, and how i would do it with the serial converters and what not. Glands I don't mind spending on, and I dont think I will be going too deep, mainly lakes, reservoirs, rivers and canals so I'm after distance rather than depth. I'm thinking of batteries in one compartment filled with mineral oil, and the arduino and control circuitry in another possibly with the electronics encased in wax, or mineral oil depending on the enclosure i choose to use. Both compartments will use glands too for all wires entering.

While posting this was just looking at the rs232 communication. Am I going to need the full 9 wires, so will need 2 lengths of cat5 for the tether?? This will give me extra wires for video.

Back on to the video camera I was looking at using something like this and powering it form the subs on-board batteries, and sending the video back up the cat5, is it suitable for that??

Thanks

elephunk: Cheers for the reply.

I have a full box 300+M of cat5 cable so i was intending on using, just hadnt investigated if it was suitable to Thanks

What i am getting at is the suitability of standard cable for underwater use.

In a relatives property the satellite cable was run around the guttering for convenience. Rainwater got in at zero pressure and syphoned itself into the satellite box as it was air cored cable. I gathered from the repair guy this is not uncommon.

Submersible tethers cannot be had from Maplins/Wallmart they are bespoke items.

Boardburner2: What i am getting at is the suitability of standard cable for underwater use.

Submersible tethers cannot be had from Maplins/Wallmart they are bespoke items.

I was thinking this, which is why i was thinking of setting. wax around the electrics, and possibly pouring wax down the ethernet cable to solidify say 10cm of ethernet internally where it passes through the gland.

Thanks

elephunk: I was thinking this, which is why i was thinking of setting. wax around the electrics, and possibly pouring wax down the ethernet cable to solidify say 10cm of ethernet internally where it passes through the gland.

Thanks

That may seal the ends.

However if there is airspace in the cable it will compress with depth. This will affect the buoyancy of the cable and increase/decrease the weight on the submersible.

Submersible cables for depth generally have a neutral/positive buoyancy. With domestic cable the problem is likely to be waterproofing however. Nailed to a wall cable is resilient to water. submerged it is not unless designed for it.

For domestic use SWA (single wire armoured ) is used for buried applications and is waterproof , very stiff and large diameter.Not for high pressure however.