tone decoder

[Melanie]

Well, if you are trying to determine if you've got VIDEO being received, wouldn't it be sensible (and easiest) to detect the FRAME sync-pulse component of a video signal?

[grounded]

thanks
and please explain with a little more detail for us non profess. hobbist

[skimask]

thanks
and please explain with a little more detail for us non profess. hobbist

To get video, among other things, you have to have Horizontal Sync and Vertical Sync pulses.
If those sync pulses come at the right intervals (depends on frame rate, resolution, video standards, etc), then you've got video coming thru.
Google it or something. You find references all over...

[Melanie]

OMG... this isn't going to become a training course in video for the hobbyist...

Here's THREE solutions...

1. Detect the Video as a whole. In the same way you would strip the audio modulation component from a Radio Carrier, you can strip the video component. Couple of Capacitors, a Resistor and a Diode. Noise (when a carrier is not present can simply be filtered away), and when video is present, you simply look for a decent voltage from your Detector.

2. Detect the Frame Pulses. The Frame Pulse is the start of each picture. The repetition rate is slow enough even for a handicapped (frequency challenged 10F PIC) to cope with. However, different cameras and standards mean that the Frame Rate could be as slow as 5fps or as fast as 120fps. Still, you're looking for a repetitive, slow pulse...

3. Detect the Line Sync. Build a sync-stripper and detect the LINE sync (my choice). You can build a sync stripper with not much more than one Transistor. The presence of LINE sync means you've definately got sensible video (in some cases Frame Pulses on their own with no other video information are used to keep a carrier link open, and since in some cases the Frame is phase-locked to the supply mains you have to make sure you're not simply detecting supply mains hum).

Now, armed with all these choices you can go and learn something about video detection and sync stripping...

[grounded]

I was going to post the below but after reading your post all I can say is
"Thanks you've giving me a reason to live" I'm gone googling
found out stripping video is not a safe search
Just to clear up.
The cam and transmitter are remote and or control by a motion sensor.
the receiver is (or will be) in my house.
the objective
simplest:
when the cam is active (because of motion) I need a indicator light to tell me
to turn on the TV and see what is being filmed.

or
down the road option
the slave board WILL turn on a tv /vcr record for x amount of time

so in a nutshell I need to know when that cam is active and sending video
and I can use that to do what ever.

I'm simple minded so simple is alway better for me.