Inventor-Bot: Table Bot
The next add-on are antennae to help the Inventor-Bot “feel” the edges of a table and then react by turning and heading in a different direction. These work by activating touch sensors when the antennae drop down about ½ inch over the edge of the table.
The book’s robot builder, Laurens Valk, provides a couple of variations on the programming of this robot to help it handle hitting the corner of the table exactly, as well as displaying left and right activation counts on the LCD screen.
For more about the book, read my Geekend post Geek Gifts 2011: The Unofficial LEGO Mindstorms NXT 2.0 Inventor's Guide.