Newsgroups: comp.robotics
Path: cantaloupe.srv.cs.cmu.edu!europa.chnt.gtegsc.com!news.sprintlink.net!noc.netcom.net!netcom.com!wiml
From: wiml@netcom.com (William Lewis)
Subject: Re: Question about Sharp's GP1U52X IR Det.
Message-ID: <wimlDB4E9r.8w4@netcom.com>
Organization: The Seattle Group
References: <gdouglas.19.0D66DEAB@gulf.uvic.ca>
Date: Mon, 3 Jul 1995 03:13:03 GMT
Lines: 17
Sender: wiml@netcom4.netcom.com

In article <gdouglas.19.0D66DEAB@gulf.uvic.ca>,
Gerry Douglas <gdouglas@gulf.uvic.ca> wrote:
>I have experimeted with the device on the bench and it appears that the 
>detector will respond to an UNMODULATED 40Khz IR signal.  Can anyone tell me 
>what the author is getting at when he/she says that the 40Khz carrier must be 
>modulated.

I've found that this detector will only assert its output for a short time
when exposed to a constant 40 KHz modulated signal. I assumed that this was
intended to reject any constant 40 KHz background. If you want continual
output, you need to pulse the 40 KHz at some lower frequency (and expect
a similarly pulsed output from the Sharp detector.)

It sounds as if some people aren't having this problem, though...

-- 
        William "Wim" Lewis * wiml@netcom.com * Seattle, WA, USA
