What about using purely mechanical sensors, for instance little flaps,
which would be deflected by grass. Using microswitch hi/low grass
could be detected. Using potentiometer or varicap the actual height of
grass could be measured. BTW, for both mechanical and optical sensors,
simple test could be used to check if they are still working - back
the robot a few feet down already cut path and read the sensors. They
should indicate low grass.
I'm thinking about augmenting vision system with sensors used
specifically to detect grass height. One of the options is adding a
second camera monted just above the grass. Drawback is the difficulty
of integrating 2 cameras with single PC without spending too much for
expensive frame-grabber. Besides, it really looks like an overkill,
when simple sensors could do the same job.
==
Paul Jurczak
<pauljurczak nospam at yahoo.com>
_________________________________________________________
DO YOU YAHOO!?
Get your free nospam at yahoo.com address at http://mail.yahoo.com