> How are you planning the cutting path ?

The most successful I've seen is tracking a buried wire. Not
sure what the signal is but the demo looked pretty good. If
you edged the area with white (painted bricks ? logs ?) you
could perhaps use optics. Industrial robots follow a white line
around their work area

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics