Subject: Re: Automatic Video Switch
References: <firstname.lastname@example.org> <email@example.com>
X-Newsreader: Forte Agent 1.93/32.576 English (American)
Date: Fri, 17 Jan 2003 11:38:37 -0500
NNTP-Posting-Date: Fri, 17 Jan 2003 11:38:38 EST
Organization: Bell Sympatico
I have read your message a few times but fail to understand what
exactly you are trying to do.
Can you rephrase your requirement ? I'll try to help.
On 16 Jan 2003 20:53:15 -0800, firstname.lastname@example.org (Jeff Artz) wrote:
>email@example.com (u1061771156) wrote in message news:...
>> In article <firstname.lastname@example.org>, Jeff Artz wrote:
>> ... details snipped
>> > Anyways, I was thinking that once I have both the DVD CV and the
>> >Receiver's Output CV, I could just use an analog comparitor and some
>> >filtering circuity (to prevent any 'false triggers') and buffer that
>> >signal to turn on the relay. That should work, right? Any
>> >suggestions for specific components?
>> > Thanks for reading my post!
>> The LM1881 sync separator chip is useful for tasks like this.
>> Given a composite video signal, it will tell you whether you have
>> valid sync or not, in a way that is immune to DC drift and picture
>> content. Read its datasheet on the National website.
>> Here in Europe, incidentally, most AV equipment has "SCART" connectors
>> which contain a pin to control input switching.
> Thanks for your suggestion, but the issue is that I want to pass the
>VCR and Sattelite Composite video to the Projector when they're used,
>but when the DVD is selected, I'd like to switch to the RGB inputs. I
>plan on doing that by 'listening' to the DVD's composite video, and to
>the selected output of the Receiver. This way, when the VCR or
>Sattelite are selected, the projector will use the Composite video,
>and when it's on the DVD player, it will switch to the RGB input from
> I figured a 'simple' comparitor circuit would work... If the
>'Input' and 'Output' signals are exactly the same (Input = DVD's
>composite Video, Output = Receiver's selected video), then the DVD is
>selected on the receiver, and a relay should be energized to select
>the RGB input on the projector.
> I don't think that I need to split out the sync, I would think that
>I can just do a simple comparison between the two video signals.