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From: mjw06513@uxa.cso.uiuc.edu (Mary Winters)
Newsgroups: sci.electronics
Subject: Re: IR remote controls
Message-ID: <1990Apr9.014530.18984@ux1.cso.uiuc.edu>
Date: 9 Apr 90 01:45:30 GMT
References: <102.261CF0A4@ofa123.FIDONET.ORG>
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In article <102.261CF0A4@ofa123.FIDONET.ORG> rick@ofa123.FIDONET.ORG (Rick Ellis) writes:
>
>That will only work if the remote uses somewhere near 40kHz for it's carrier 
>frequency.  (It's also dependent on how picky the receiver is.)

I've been experimenting with IR control of VCRs, and the Radio Shack IR detector
module in particular. The detector module is made by Sharp, so it's fairly
safe to assume that at least some Sharp products use 40kHz. The detector also
properly decodes signals from my Sony and JVC remotes. Also, according to
Steve Ciarcia in a Circuit Cellar article, most IR remotes have carrier
frequencies between 32 and 48kHz, and he presents a circuit which will detect
across that range. In my experiments with my Sony deck, the detection circuitry
appears to have a fairly high tolerance (around 10%). I suspect most decks 
have fairly wide tolerances to accomodate for poor aim, weak batteries, and
other adverse working conditions in the home environment. For a few $ in parts 
from the Shack, you can find out if your remote uses a 40kHz carrier (and it's 
a lot of fun finding out).




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