Using an IR photo detector you are going to get a LOT of variance in your
distance readings depending on what the light is reflecting off of.  A
"triangulation IR" detector like the GP2D02 will be *much* more stable and
consistent in it's measurement, because it actually triangulates the
reflection - like a laser range-finder.

----- Original Message -----
From: "Kevin A. Benedict" <kben@DCA.NET>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, December 20, 2001 8:47 PM
Subject: [PIC]: PIC IR Proximity Detector ?


> Hi,
> I am trying to build a PIC IR Proximity Detector, the bascic TX circuit
> is figure 2 on this page >>>
> http://www.rentron.com/Infrared_Remote_Control.htm
> If I add a small resistor (10-330 ohms) between the IR led and gnd,
> it changes the distance the RX circuit detects a reflection from
> (10cm -120cm)
> So, I thought if I add a digital pot instead of manually changing
> the resistor,
> I could make a rudimentary IR Proximity Detector.
> Problem Digikey only sells a 10k digital pot, I was hoping to find a
smaller
>
> one,like <= 1k, anybody know where I could get one ?
> Is their an easier way to do this with a PIC ?
> I already looked at the Sharp GP2D02, but I wanted someting cheaper.
>
> Thanks in advance,
>                    Kevin
>
> P.S. I am a programmer not an EE, so my electronics background is limited.
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>
>
>

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