Why not just place a powerful laser in horizontal position one inch above ground, and let it circle over the lawn and burn off the straws once every night. It may be expensive but it's reliable. Then a PIC connected to an Iomega could be used to control a sprinkler system to put out any fire.

If a large area of grass is to be cut, for example a city park or a golf court, a bigger laser could be put in a tower in the middle of the golf court. Using a PIC connected to a framegrabber for 3D vision, all grass straws are measured and shot off if they are too tall. This system could also be used as a burglar alarm detection system for large areas. It can not just be used to detect burglars, it could also be used to eliminate them. However, the golf ball thiefs could use PIC chips to build a system that fires out water baloons and positions them between the laser tower and the burglar, to prevent him from being hit by the laser beam. Does anyone have any source code for a PIC-controlled anti-missile system (I don't know where to start)?

Glenn
Sweden


-----Original Message-----
From:   Jack Warren [SMTP:warren@UNITRODE.COM]
Sent:   Tuesday, November 18, 1997 2:49 PM
To:     PICLIST@MITVMA.MIT.EDU
Subject:        Re: Robot Lawnmowers

Several years ago there was a series of articles in Radio-Electronics (I
think?!?!?) which was a do-it-yourself autonomous lawn mower.  It used a
series of split IR emitter/detector pairs to sense the "length" of the grass
blades.  The steering mechanism attempted to keep half of the IR pairs in the
uncut grass.

Using this method, you mow around all of the obsticles in the yard, then go to
auto mode and let the mower do it's thing.  I'm not sure what it did when it
got done...


Regards,
Jack Warren