[Rick TYler]

It's kind of off-topic (my bad), but it does touch on one design decision made by most teams I saw in Portland and here on CD, too. The ball collectors were usually made by putting a roller on the end of the 'bot, either with a conveyor belt attached or not. Since the roller (or belt) needed to push against something, there was either another roller, another belt, or a plate of some kind on the inside edge to provide pressure for the ball to be moved upwards.

After building three (3) prototype collectors we put the roller on the inside, and a pressure bar on the outside of the robot. The ball squeezes under the bar, which is set about 5.5 inches above the floor, and then is trapped between the conveyor belt on the inside and a pair of vertical rails at the end of the bot. The ball rides up the rails, and is then deflected into the hopper by a curved piece of Lexan. This kept all the delicate spinning bits on the inside and only a strong and easily-replaced pressure bar on the outside. Our pressure bar was bent, but the collector would still have worked (if we had a hopper, which is another story altogether).