The main brain for the LawnBot is an ATMEGA168, programmed wtih BASCOM.  It doesn't need to do much but interface wtih an on-board GPS, and the 433 MHz control channel for steering.  GPS you say?  Yes, the project has the capability of automatic guidance, but I'm a little hesitant to use it until I can add a section in the code to avoid obstacles.  If anyone would like any more info, I'd be glad to post it.  Just kinda added this to HackaDay for the heck of it.