Re: [mowbot] A Lurker Says, "Hello".

Dominic Peterson (d.peterson nospam at
Tue, 24 Sep 1996 11:37:58 +1000 (EST)

Robin wrote:
>Dave Everett wrote:
>> It may be possible to create a colour
>> sensor
>> that was responsive to the rough colour of grass. This is not as far
>> fetched
>> as it sounds, there are SMD chip colour sensors that I have heard of.
>> Green
>> of course like blue is a difficult colour to sense, but by using filters
>> it might be possible to eliminate the need for a boundary wire type
>> system.
>This sounds like an interesting possibility. Rather than sensing colour
>per se, perhaps a whole suite of ground-looking sensors (including IR
>and ultrasound) would give us enough variables to reliably identify the
>type terrain. What are we likely to encounter? Grass, obviously, (but
>different varieties and lengths will probably exhibit somewhat different
>properties), earth, tree root, paving stones, tarmac, brick, concrete.
>Most of hte man-made surfaces are hard and flat and so should give a
>good ultrasound echo.

I seem to remember (read it? told by someone?) that IR satellite photos
could show the difference between harvested and unharvested crops based
on IR. Does (recently) cut grass have a different IR response than
un-cut. Hmmm, time to crawl around the yard with an IR sensor and a
meter, enduring the curious stares of my neighbours (again/still!).

>btw Dave, why do your posts have such erratic word-wrap?

His default line length is probably set about 5-10 chars longer than
yours. I've deliberately inserted line breaks into my text to try and
avoid this problem.

Best regards,


Dominic Peterson Email: d.peterson nospam at
Systems Analyst Ph: +61 (07) 3864 4286
Queensland University of Technology Fax: +61 (07) 3864 1808
Brisbane, Australia 4001
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