Subject:
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Re: Color sensor and brick mixer MOC
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 29 Apr 2002 19:20:51 GMT
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Viewed:
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807 times
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This is a very well documented piece of work! I like it. And a very masteful
work of miniaturization given that you are using big through hole parts!
I am also working on a color sensor, although the details are different, the
principle is the same, to illuminate the subject suface with different
wavelengths to attempt to deduce the color.
I have not succeeded in making the device very reliable yet in terms of the
repeatability of readings under different ambient lighting conditions and
worst of all under conditions of varying sample surface angle. The distance
from each LED to the surface makes a very big difference to the amount of
signal that comes back from that LED and thus skews the color estimation.
Have you encountered that problem? I have tried using symetrical
arrangements of two red, two green and two blue to try and balance the skew
effect but I can't get a steady reading from a single color surface yet.
I also note that you have discovered that Lego green is in fact black! Me
too! I am trying to find a slightly shorter wavelength green LED but so far
no luck. There are some new blue/green devices available I believe, but I
have only seen them in small smt packages so far.
I see a color sensor as a worthy challenge however and one which will make a
big difference to what can be done with RCX in the future.
My primary goal is to build an M&M sorter ...
JB
In lugnet.announce.moc, Philippe Hurbain writes:
> Hi everybody,
>
> I finally found time to complete the description pages of my latest (linked)
> creations:
> - A RCX compatible color sensor that measures reflection of red, green and
> blue light, http://www.philohome.com/sensors/colorsensor.htm
> - A brick sorter to use this sensor,
> http://www.philohome.com/bricksorters/sorter3.htm. This one can be built
> with RIS and Ultimate builders set, and may use light sensor (with reduced
> sorting capabilities). Includes building instructions.
>
> I also gathered some photos of my previous brick sorters implementations,
> see them at http://www.philohome.com/bricksorters/sorter1.htm and
> http://www.philohome.com/bricksorters/sorter2.htm
>
> Enjoy !
>
> Philo
> www.philohome.com
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Message has 1 Reply:
 | | Re: Color sensor and brick mixer MOC
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| Hi John, (...) ;o) (...) Yes - and I think it is difficult to avoid. That's why my brick sorter places the brick in a fixed location, relatively shielded of ambient light. In this controlled environment, the color sensor is very reliable, and (...) (23 years ago, 30-Apr-02, to lugnet.robotics)
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Message is in Reply To:
| | Color sensor and brick mixer MOC
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| Hi everybody, I finally found time to complete the description pages of my latest (linked) creations: - A RCX compatible color sensor that measures reflection of red, green and blue light, (URL) A brick sorter to use this sensor, (URL) This one can (...) (23 years ago, 29-Apr-02, to lugnet.announce.moc, lugnet.robotics) !
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