Ive added video of Claw-Bot, the robot from Chapter 13 of The Unofficial LEGO MINDSTORMS NXT Inventors Guide, to the Pages section of the blog. You can also watch the video below.
Claw-Bot is based on the Zippy-Bot model from Chapter 11, adding a claw-like subassembly with an ultrasonic sensor and a light sensor. Claw-Bot moves toward the center of the NXT test pad, spins in a circle until it detects an object with its ultrasonic sensor, and then drives forward to push the object until its light sensor detects the black line. The robot is programmed to find three objects, but it’s easy to change the number to more (or less) than three. Go Claw-Bot!