Quite some time ago I built a Herbie Junkbot mouse. I liked the simplicity of the op-amp chip and the relay to determine motor direction. I was also looking at six-legged robots. The original lego site with the leg layout has since disappeared. Here is the closest site
I can find now.
The design can also be seen in the six-legged kit addition to the Boe-Bot. Jameco
and others carry the kit. There's just something about a multi-legged robot that is so cool!
So I decided to combine the Herbie brain with the Boe-Bot six-legged body and throw in feelers.