Thursday, July 12, 2007

Meeting 008

Today we had some special guests for the latter half of the meeting; Naomi (3.5), David (8), and Isaac (12) Wilcox joined us while Mom hit the Whole Foods store nearby.

We are continuing our process of refining the mechanisms we've settled upon. Today we worked on the tram portion of the robot, first trying a worm-gear-based movement that was ultimately unsuccessful. Laura suggested we return to the "Cinderella's coach" design, thinking that big gears would look good.

That led to a discussion and demonstration of gear ratios and speed versus torque. It was noticed that the tiny gears we'd used for the past couple of weeks were not moving smoothly; their radius is just a bit too tight. David suggested the next largest gears, and I included a smaller pulley than we'd tried before. The combination of the new gears and pulleys gives us a faster tram movement than we'd seen, which should be advantageous, as long as it doesn't go too fast for our sensing mechanisms.

Of course, David wasn't always helpful. He also insisted on testing the tram movement via the remote every time I tried to attach a piece to it.

Isaac dug out one of the large Lego figures that was in our box, and decided to "Busterize" him; so now we have our own version of "Buster," the crash test dummy from the Mythbusters TV program.

We expect to use a color contrasting tile and light sensor to determine which hopper the tram stop at. Movement at the extremities will be limited by stops and governed by the belt drive we are using, so we don't have to be particularly precise for those calibrations.

Today I found myself doing much of the building. I need to figure out a way to increase the Lego building experience of the rest of the team. Laura has done quite a bit, but none of it Technic--which was my own case before MindStorms was released. Several team members are talking about purchasing their own robotics sets, too, but no one has gotten past the "talking about" stage.

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