For sure. I'd love to see a more efficient way of doing it too. A common problem is that sometimes devices requires a larger voltage than the board delivers. Plus you don't want the options narrowed because of those limitations. Since relays are cheap as are the 595's, until there's a better option, that would be my immediate choice.
You could pulse the motor to manage speed, which is actually quite ingenious when you think about it. I don't think pulsing would be inefficient either.
An object of neutral buoyancy also wouldn't need to conform to any particular shape. You could use a ping pong ball, for example, attached to shaft attached to two rotary encoders to determine the objects tilt for staying flat in the water, and using thrusters for making corrections. The ROV could be the shaped like a ball, hypothetically.
Once I'm over my current back log of work, and other projects I'm working on, I'd definitely like to put all that to the test.
hey,
i saw there was a reply to my thread just before i posted the last one. heh heh. i guess this is going to result in a double post. srry. but wouldnt a crude PWM in a mechanical relay make it vibrate and kill the battery? thats why i said it would be inefficient. I dont think ill need a 595 because i only need 3 motors. would going 595less not let me do the reversing polarity trick to reverse the motors? I thaught about the neutral buoyancy, it would definitely be ideal but it will work fine for my purposes for the time being.
The roll compensation idea would work but that would over complicate it. but if i use a neutral buoyancy rig with weights on the botem and foam at the top than it would also prevent roll. As for the wired/wireless situation, i think im going wired for the time being. i think cat5 cable is cheap. i dont know if it will carry video, definitely not if its analog. i have no idea what im going to with the camera. even though im going wired id like to keep the arduino, batteries etc underwater. it should make any future updates to wireless slightly less painless.