Hi Dale,

If you wany any degree of relaibility, I'm afraid you cannot really avoid
the 40 KHz (or thereabouts)  modulation. Having said that, I think the best
article that would guide you to do precisely what you want is at the
Parallax site at
http://www.parallaxinc.com/html_files/resources/wknd_specials.htm


----- Original Message -----
From: "Dale Botkin" <dale@BOTKIN.ORG>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Saturday, August 24, 2002 11:31 PM
Subject: [EE]: IR object detection


> Hi all,
>
> I'm looking at an object detection problem for which I want to use a
> simple, cheap IR LED/phototransistor pair.  I plan to have each rigidly
> mounted and aimed, say a meter or so apart, and can use a flat black
> tubular shroud say half an inch to an inch in length at each end.  I could
> probably also use an IR filter on one or both ends.  In an environment
> with high ambient light levels, like outdoors, the sensor would either be
> pointed downward or parallel to the ground.  Does this sound like it's got
> a chance of working most or all fo the time, or is this doomed to fail if
> used outdoors?  I'd hate to have to resort to using a 40kHz modulated
> beam, and I'm not sure that it would make that much difference outdoors.
> Who's been here already?  This is the first time I've looked at using IR
> for a project like this.
>
> Dale
> ---
> We are Dyslexia of Borg.
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>
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