Use a standard IR- receiver component like 

SFH 506-xx  (xx is for the modulation frequency) from siemens
or
TSOP 12xx, TSOP 11xx, TSOP17xx from TEMIC/VISHAY



regards

¯yvind Standal
Nortroll AS

Tlf:      +47 74085514
Faks:  +47 74085501
email:  ostandal@nortroll.no
web:   www.nortroll.com





----------
From:   AndrŽ  Malafaya Baptista[SMTP:ABaptista@SE.EFACEC.PT]
Sent:   12. november 1998 15:13
To:     PICLIST@MITVMA.MIT.EDU
Subject:        Re: IR barrier and sunlight

Hi Tom.
I think that is not the problem.
What Leonardo says is that the light may SATURATE the IR receiver. That
means the receiver will always be in ON state. Modulating the signal won't
do any better because the receiver is already receiving IR.

Regards,
AndrŽ Malafaya Baptista


-----Original Message-----
From: Tom Handley [mailto:thandley@TELEPORT.COM]
Sent: Quinta-feira, 12 de Novembro de 1998 09:29
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: IR barrier and sunlight


   Leonardo, in addtion to a light shield such as a tube, you want to
modulate
the IR beam. A simple way to do this is to pulse the beam at a given rate
and
have the receiver look for missing pulses. We use to use 555 timers for this
before microcomputers, in saw mills and other environments. You can also get
IR filters that are nearly opaque to ambient light. We used all three.

At 03:33 PM 11/11/98 +0100, Leonardo De Palo wrote:
>Hi PICer,
>
>I have the necessity to count object, using a 16F84.
>
>My idea is to use a couple of infrared diode and receiver (like the IR used
>on TV).
>
>But, thinking at the environment of the installation site, it possible that
>some sunlight can arrive to the sensor, and I suppose that sunlight can
>saturate the receiver photodiode.
>
>I have the idea to try to minimize the effect of the undesidered light with
>some black plastic tube, but before to begin to build the prototipe, I
would
>like know if exist a method to drive the LED to ignore o reduce the
sunlight
>saturation effect.
>
>Anyone have some idea??
>
>Ciao
>
>Leonardo