PBP projects for R/C models

[ScaleRobotics]

At high speed, I worry that without some sort of reference point, your car will get "lost". If you add a cheap line sensor, you could add something like a 4" black tape reference point to one of the walls or floor beside one of the 4 walls. How accurate are your sonar readings? Can it measure the room from each corner successfully? If not, then you may need to add a cheap wheel sensor to measure distance. Really both of these would be dirt cheap, but yet add a new dimension to your car finding itself, as well as sensing it's speed. (although you could use your sonar to get speed. It would not be accurate as you turn a corner though. It will think you are going backwards as it senses the wall getting further away)

Has the "Robotics for Dummies" paper back been published?

I think it's scheduled to be released right after Pic Basic Pro for dummies.