Wireless video rov in pool

This is one carried over from the old forum

Troy,

1. Radio through water. Video bandwidth is 8MHz, so theoretically carrier frequencies down to 120MHz are possible, but I don’t know anyone who has done it, and I suspect that even at that frequency transmission through water would be very limited. Standard model radio control gear uses 75 mW power on 27 or 40 MHz, and that only works reliably through a couple of metres of fresh water. An optical link using fibre optic Tx and Rx diodes with diverging lenses might be an easier option in a clean swimming pool? Still pretty ambitious though, simplest solution would be to have the ROV tow a surface buoy with aerials.

2. Vertical control. ROVs don’t use ballast tanks, they are carefully trimmed to be as near as possible to neutrally buoyant, then need a relatively small thruster force to move up or down. The only reason submarines use tanks is to make them positively buoyant when on the surface, once submerged they are trimmed neutral and use planes or thrusters to control depth.

3. Camera. Best bet is to encapsulate a cheap board camera: Glue a disk of 6mm or thicker acrylic over the front of the lens, making sure it is sealed all round so resin can’t seep in, seal up all holes in the plastic lens housing with epoxy. Find something to use as a mould, and arrange the camera in it so that when filled with resin the resin won’t go over the acrylic viewport (I do this by sticking the viewport to the bottom of the mould with double sided tape), Then fill the mould with polyurethane or epoxy potting compound.

4. Motors. The housings and seals are more of a problem than the motors themselves (see some earlier posts on this forum). Solutions that some home builders have used: a) model aircraft motors with reduction gears, b) cordless drill motors which have an integral gearbox, c) submersible pumps, which have the advantage of already being waterproof, d) electric outboards (trolling motors).