Subject:
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Re: IR Collision avoidance
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Sun, 2 Mar 1997 22:14:48 GMT
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Original-From:
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Keith the wonder wookie <kas219@psu.[NoSpam]edu>
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Viewed:
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1914 times
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>
> The transmitter is basically a modulator made from two 555 timer chips.
> One timer does 200-1000 Hz (we use 500) while the other does 38 KHz. On
> a scope, the output looks somewhat like..
>
> |||||||||| |||||||||| ||||||||||
> | | | | | |
> | | | | | |
> ----------- ----------- ----------- ----------
>
> ^ ^ ^ ^
> One complete cycle The high of each cycle
> of 500 Hz pulses the 38KHz
>
> The tone decoder (receiver) demodulates the signal. If is senses the
> 38KHz signal it puts out a logic one (or zero depending on design) that
> can go to any available digital port. The port is processed like...
I have a few questions for you. How did you combine the 38khz and 500hz
signal. In a design that I am working on now I have two signals similar to
yours and an enable signal running into a three input AND gate. I haven't
built it yet but it simulated correctly. In my design I am going to have
14 individual sensors being activated and sequenced with a decoder and
multiplexor. I want to have the external circuits of the signal do as much
work as possible so that the CPU has more free time. I need to know if I
can use a 567 tone decoder to sense the 500 Hz signal coming from the
detector. This is important to me because I can't have the CPU constantly
looking for the signal. Thanks for all your help. If you have no idea
what I am asking or need more information please e-mail me.
Keith
Keith Soldavin
kas219@email.psu.edu
http://www.personal.psu.edu/users/k/a/kas219/
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Message has 2 Replies:
 | | Re: IR Collision avoidance
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| Well, at risk of being branded a heretic, since you've brought up the issue of modulated IR, I'm going to throw out an observation I've made about the Radio Shack IR sensors which several other people on the mailing list have privately disagreed (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
| | | Re: IR Collision avoidance
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| Actually, I built the (...) This is exactly the same scheme I use. I'm using an IR module from Digi-key that has a side view, and five IR LED's spread around the front of the module at different angles. I have quite a few outputs, thanks to a little (...) (28 years ago, 3-Mar-97, to lugnet.robotics.handyboard)
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