Subject:
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Re: IR Port as Proximity detector.
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 8 Jan 1999 10:01:08 GMT
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Original-From:
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Simen Svale Skogsrud <simen@mopSPAMCAKE.no>
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Viewed:
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1246 times
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David Chen wrote
> Someone (Can't remember who, so unfortunately unable to give credit for
> the idea appropriately) posted the fact that the IR port used as a
> emitter coupled with the Light Sensor unit as the reciever can be used
> as a IR proximity sensor.
eh... twas me.
As for programming goes the fluctuations in light intensity is fairly large
(typically 100-200 RAW units when facing a wall or anything) I have had
great success not setting a specific threshold in the code, just sample the
light-sensor at regular (rapid) intervals and look for huge fluctuations.
An algorithm somewhat like
if abs(oldsample-newsample) > 100 then you are nearby something
if you do it like that you will not depend on any specific ambient
lightning level.
The magnitude of the spikes are fairly proportional to the distance to
reflector, it seems that by using two light-sensors (which I don't have)
you would be able to determine fairly accurately the general direction of
the obstruction that are bouncing back your IR messages.
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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