Subject:
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RE: Line Followers
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 16 Nov 1999 04:26:56 GMT
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Viewed:
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587 times
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> With just one light sensor, the problem is that you have to guess which
> direction you just fell off the line. i.e., your sensor suddently goes
> from dark to light. Is the dark to your left? Your right? There's no real
> way of telling, is there?
One way around it is a specially graded line. It's black on one side and
light on the other, sort of a dark grey in the middle. Try to keep the sensor
in the dark grey area.
> With two light sensors, this suddenly becomes much easier, and with
> three, you can build a great light sensor. However, forks still aren't
> dealt with well- you need depth as well as breadth to be able to analyze
> those robustly and on the fly (in my opinion). Anyone have any thoughts
> on that one?
Yes. Now that I have solved the maze problem on paper with the mazewalker
at:
<http://www.hempeldesigngroup.com/lego/mazewalker/index.html>
It uses depth and breadth techniques to "map" and "solve" the maze.
I'm going to eventually try a wheeled bot that follows a maze on the floor.
Once again, I'll keep to the idea of line segments of fixed length and
and only four directions, but once the simple problem is solved, more
general solutions would be fun.
Cheers,
Ralph Hempel - P.Eng
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Check out pbFORTH for LEGO Mindstorms at:
<http://www.hempeldesigngroup.com/lego/pbFORTH>
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Reply to: rhempel at bmts dot com
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Message has 2 Replies:
 | | RE: Line Followers
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| (...) At some point, my letter had a point about "cheating" by shading the line or edges of the line, which I guess I took out. I've built a large "sumo pit" built on this principle (the floor is shaded with flat black and glossy white spray paint) (...) (25 years ago, 16-Nov-99, to lugnet.robotics)
| | | Re: Line Followers
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| (...) You don't really need to shade the line. Start with something like a 3/4" wide black line over a white background. If the light sensor is over the edge between the line and the background it should read a value midway between "black" and (...) (25 years ago, 16-Nov-99, to lugnet.robotics)
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Message is in Reply To:
| | Re: Line Followers
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| With just one light sensor, the problem is that you have to guess which direction you just fell off the line. i.e., your sensor suddently goes from dark to light. Is the dark to your left? Your right? There's no real way of telling, is there? If you (...) (25 years ago, 16-Nov-99, to lugnet.robotics)
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