easy video detection circuit?

[Desmond Wong]

Hi,

Is there any way on detecting video easily? Like testing for voltage on the
output without corrupting the video signal output?

I don't want to get into something where it detects sync signals, etc, just
looking for an output that I can then couple to a relay...etc...etc...

Des.

 

[Mark Little]

"Desmond Wong" <des_nospam@ihug.com.au> wrote in message
news:ccogd4$k89$1@lust.ihug.co.nz...

Hi,

Is there any way on detecting video easily? Like testing for voltage on
the
output without corrupting the video signal output?

I don't want to get into something where it detects sync signals, etc,
just
looking for an output that I can then couple to a relay...etc...etc...

How easy you can make it depends on what will be present if there is no
signal.

If only residual noise will be present when the video signal is missing, it
is a simple matter to set a peak detector to a level that will be above the
residual noise and below the peak video signal. This can trigger a
re-triggerable monostable multi-vibrator and bingo! you have a detector.

If the no video ouptput contains a lot of noise, then you will have to go to
detecting the sync.


Mark

 

[Russell Griffiths]

"Desmond Wong" <des_nospam@ihug.com.au> wrote in message news:<ccogd4$k89$1@lust.ihug.co.nz>...

Hi,

Is there any way on detecting video easily? Like testing for voltage on the
output without corrupting the video signal output?

I don't want to get into something where it detects sync signals, etc, just
looking for an output that I can then couple to a relay...etc...etc...

Des.

Greetings Des.
I seem to remember a circuit sent in by a reader to E.A. or S.C.
I will look through the indexes I have made of all the circuits
in The magazines and let you know if I find one that will do
the job you want.
Russell.

 

[Russell Griffiths]

rg26ce1991@hotmail.com (Russell Griffiths) wrote in message news:<13cdb672.0407110450.1df4ad3b@posting.google.com>...

"Desmond Wong" <des_nospam@ihug.com.au> wrote in message news:<ccogd4$k89$1@lust.ihug.co.nz>...
Hi,

Is there any way on detecting video easily? Like testing for voltage on the
output without corrupting the video signal output?

I don't want to get into something where it detects sync signals, etc, just
looking for an output that I can then couple to a relay...etc...etc...

Des.

Greetings Des.
I seem to remember a circuit sent in by a reader to E.A. or S.C.
I will look through the indexes I have made of all the circuits
in The magazines and let you know if I find one that will do
the job you want.
Russell.

Greetings again.
The circuit is in E.A. November 1985.

Bye,
Russell Griffiths.

 

[Dave]

On 19 Jul 2004 19:07:40 -0700, rg26ce1991@hotmail.com (Russell
Griffiths) wrote:

rg26ce1991@hotmail.com (Russell Griffiths) wrote in message news:<13cdb672.0407110450.1df4ad3b@posting.google.com>...
"Desmond Wong" <des_nospam@ihug.com.au> wrote in message news:<ccogd4$k89$1@lust.ihug.co.nz>...
Hi,

Is there any way on detecting video easily? Like testing for voltage on the
output without corrupting the video signal output?

I don't want to get into something where it detects sync signals, etc, just
looking for an output that I can then couple to a relay...etc...etc...

Des.

Greetings Des.
I seem to remember a circuit sent in by a reader to E.A. or S.C.
I will look through the indexes I have made of all the circuits
in The magazines and let you know if I find one that will do
the job you want.
Russell.

Greetings again.
The circuit is in E.A. November 1985.

Bye,
Russell Griffiths.

There is another circuit described in Silicon Chip, January 2004. You
can see it by going to siliconchip.com.au and searching for "video
tracer" "circuit notebook"

HTH

Dave