The following is Dave's description of his latest creation, complete with building instructions and two programming files:
"This puppy is all ready to go for a walk, either with his leash, or on the loose by himself. He can go straight or turn on smooth floors, and he can turn his head to look left and right.
Two programs are provided. With the leash program, you can control when the puppy stops and turns left or right by pushing the button on the leash. Without the leash, the alternate program makes the puppy explore around the room by himself, trying to avoid walls with his ultrasonic "eyes", and you can also get him to turn in one direction or the other by calling him, and he will hear you with his sound sensor and come to you!"
Thanks, Dave (again).