Subject:
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Re: IR for bots
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 28 Mar 1997 04:19:36 GMT
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Original-From:
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Richard Vannoy <RICHARDV@ABAC.COMsaynotospam>
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Reply-To:
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richardv@abac.+spamless+com
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Viewed:
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1468 times
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> Or is it necessary to inject another frequency on the 40 Khz that can be
> decoded? Then the output of the decoder (like a 567) is read by the HB.
> I understand that tone encoding allows for multiple tasks on one
> carrier, But my main interest here is for object avoidance.
Our robot worked well with a dual 555 timer. 38KHz for the IR and
combined with a 500 Hz square wave. When the square wave was high, 38K
was on, making it a 50% duty cycle transmission. As I understand the
receiver circuitry, it was tuned to 38K. Worked fine for us, but I
don't know the correct answers to why 50%? Why modulate? Why not just
straight 38K?
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Message is in Reply To:
 | | IR for bots
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| Hello everyone, My thinking (albeit limited), has been that simply driving an IR LED with ac (ie:40Khz) as opposed to static dc, is enough to discriminate it from other frequencies like 60 Hz. or whatever. Then, when the detector picks up sufficient (...) (28 years ago, 20-Mar-97, to lugnet.robotics.handyboard)
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