Wednesday, August 24, 2011


Working on making a radar type sensor with a Parallax rangefinder mounted on top of a servo motor. Left is raw distance data (2-300 cm), drawn in polar coordinates, and right is *supposed* to be corrected into rectangular coordinates. But they look eerily similar so I'm not sure that's working yet.

But the big accomplishment is the beginnings of an object detection system, as note by the white boxes. Basically if the points are close enough together, there must be an object there.

The problem is figuring out how close is close enough. As you can see, there are lots of tiny boxes that should probably be combined into one big box, as well as really big boxes that are overlapping smaller discrete objects.

Too many little boxes are a problem for memory & speed (right now it's sensing over 4,000 objects, but there are only 90 dots!). It would make more sense to combine them into one "wall" object, with the same effect.

The really big box is a problem, because the robot would see that entire area as an object, and avoid it; it would never move forward.

The moral of the story: weak object detection makes for slow, paranoid robots. Smarter = faster = more risk tolerance = more exploration!

Tuesday, August 23, 2011

Richard Serra Driving

Pieces of a Richard Serra sculpture driving toward the George Washington Bridge...

Finally, some art in the suburbs...