Maybe you could hire a roach to drive it instead? *grin*


It's been a really long time since i've had to cut grass since the
majority over here live in apartments. I probably won't get a chance to
try this out anytime soon but will there be an easily defined difference
between the uncut and freshly cut grass?


If there is, couldn't a simple pair of hand-formed wires attached to leaf
switches track the boundary between cut and uncut grass? Something like
how kids enjoy walking through a clothing store with their hand brushing
through every item of clothing hanging on a rack.


If so, the controller should navigate the mower so that the 1st wire is
constantly brushing against the uncut grass and the 2nd shorter wire does
not contact any grass. (Debris from the mower should be expelled as far
away from the tracking wires possible. Doesn't matter if it lands on the
cut or uncut side.)


This method should make a really simple "open field" concentric uncut
grass follower possible. Make the first cutting path manually (preferably
with a nice turning radius for the mower bot to track) and let it do the
rest. It should shut down after say 15 seconds of going round in circles
and unable to find anymore uncut grass.


Obsticle avoidance will require a controller with some smarts and i'd go
with at least a 2 bumper switch design. 3 may be better, front Left
corner, front center, front right corner. A bumper gets hit, reverse a
little, turn a little to the cut grass side and "feel" it's way around
the tree, bricked up flower bed, dead cat, etc till it finds the uncut
grass and starts tracking again.


Last note, install a huge red emergency stop button on the top of the
mower.


Cheers

Terry


Design Consultant

T3DESIGN

Innovative Product Development

<italic>Thinking out of the box.

</italic>


At 01:18 PM 8/31/01 -0500, you wrote:

>After watching my bot crawl across the bumpy yard, sans brains at this

>point, I can tell you that dead reconing will fail immediately.  The
thing

>doesn't even cut a straight path, kind of wanders back and forth,
climbing

>up and down the bumps and over cats, baseball bats molehills etc.

>

>Standard GPS is not accurate enough for mowing control.  But it would
be

>accurate enough for theft control (see long thread March 2001)  to tell
when

>your bot had left the yard.  What's the cheapest GPS on the US side of
the

>water?

>

>--Lawrence

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