Subject:
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Re: IR Detection
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Mon, 2 Nov 1998 02:12:16 GMT
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Original-From:
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Darkman <lroska@cyberus.NOSPAMca>
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Viewed:
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1750 times
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Hi
Most of the IR LED's sold at Radio Shack are the 840-880 nm wavelenght type.
The Sharp tin can requires the 940 nm wavelength IR beam if my memory serves
me right, it also requires to be modulated at 38 or 40 kHz depending on the
model. This 38 or 40 kHz should also be modulated on and off to get a
response from the sensor.
I currently have the IRPD http://www.robotstore.com/ hooked up to my Handy
Board and have good results.
If you go that way let me know and I 'll send you some code in c.
I hope that helps and correct me if I'm wrong!
-----Original Message-----
From: Rajbala Makar <makarraj@cse.msu.edu>
To: handyboard@media.mit.edu <handyboard@media.mit.edu>
Date: Thursday, October 29, 1998 8:43 PM
Subject: Re: IR Detection
> > > Hi Everyone:
> > >
> > > I am trying out the infra red emission and detection with
> > > the Handy Board. I have succeeded in the emission part
> > > but the detection circuit is not working. I know that
> > > the emitter LED is fine , with the help of Radio Shack
> > > Infrared sensor card. can anyone give me any hints as
> > > to how to get the sharp detector to see the radiations
> > > or maybe do it with the help of any other detector also.
> >
> > The Sharp IR detector is designed to respond only to modulated IR • signals.
> > The card from Radio Shack will indicate whether the LED is illuminated,
> > but it won't tell you whether it's modulated at the proper frequency.
> > Perhaps that could be the problem? Just a guess. Good luck!
> >
> > --Will
>
> Hi Will:
>
> What you say might be the reason for my problem hence I bought a
> matched IR emitter and detector pair from Radio Shack and tried the
> same thing. Here again, the emitter is sending the signal but
> the detector is not able to see it. I tried connecting the receiver
> to a digital port directly without any resistor and analysing the
> input from the port by using the digital(int) function. It did not
> show any level change. Basically, I am trying to
> implement something similar to the REC 80 routines by Danny Negro
> and Max Davies' work. I hope to be able to transmit the codes
> from the IR transmitter of one handyboard and have another HB
> receive and decode the signals. I even tried Sriram's code (I got
> it from the HB mailing list archives ) which
> sends out a signal similar to that sent out by the sony remote but
> the Sharp Chip was still not able to receive/decode it.
> Another question I have is, if I want my handyboard to send signals
> in different directions, do I need to have as many detectors as
> emitters or one detector will do?
>
> Thanks for your help.
>
> Raj.
>
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