14 Aug 2006 tbenedict   » (Master)

The ROV is done. I installed a two AA battery holder to supply power, and everything ran fine. Buoyancy was added in the form of foam pipe insulation and zip-ties (though it takes on some water during use, and changes the slight positive buoyancy to slight negative buoyancy... not so good.) Ballast was added by tapping two of the holes in the plexi and installing two #8 screws and enough washers to balance it out. If I do change out the buoyancy for something else, changing ballast to match is dead-easy.

The only real gotcha is the tether: It's too stiff for the mass of the ROV. Since the current levels are so low (3V at 1.6A) I can switch to lighter wire and get more flexibility out of it. This is still in the R&D phase, though I've got an old serial mouse cord I'm going to try out.

The motors are quite strong, and can propel the little thing plenty fast. I can't wait to replace the tether with lighter wire and take it out for a spin in some open water. (Well, more open than the five gallon bucket I'm using.)

I need to step up my efforts on my mini-sumo. I found out there's a competition in Hilo in December, and one of the events is mini-sumo. (The other is line following, which I also want to build a bot for, preferably using the aging 68HC11 MiniBoard I've got on my bench. But I need to see the rules first to see if I'm dealing with right angle turns.)

The big mods to the mini sumo will be side and back-looking IR proximity sensors, and to move the center edge sensor on the front scoop to the back of the bot. This will require a fair bit of re-coding on my part, but should make it survive a little longer in the ring.

Can't wait!


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