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Trigger Function - n Time Prior

Posted: Fri Sep 09, 2016 9:30 pm
by dmroeder
Hello,

I have ZM installed on a machine running Linux Mint (Mint 18, ZM 1.29.0), I've been tinkering around for a couple of days and everything is working great. Got it installed and recording pretty quickly. For testing, I setup the trigger and set my camera to nodect, sent a command via Python and I'll be darned, it worked first try!

My project I'm working on is monitoring a machine in our shop. From my machine, I can get status when it faults, I can send that to ZM and trigger it to record (and this currently works). This may sound silly, but what I really need is a certain amount of time prior to the event to see what might have caused it. So I imagine it like this, I'm constantly recording, an external event happens, save an event at 20 seconds prior to the trigger and record for the next 20 seconds (sent with the external trigger). I searched around for a bit and although I've seen a few posts asking for what seemed like the same thing, I didn't see any responses.

Should I just forget it? Or does anyone have a clever way to accomplish this?

I was thinking that a round about way would be to have a constant recording and a nodect on the same monitor. Then when I see an event on the nodect, I could try to find that point in the constant recording. It would just be a little clunky. Especially if you showed up an hour after the event happened.

Thanks for reading!

Re: Trigger Function - n Time Prior

Posted: Sat Sep 10, 2016 11:07 am
by SteveGilvarry
In monitor setup go to Buffer tab and checkout pre and post event buffers. Never tried that with triggers, but I believe it should work. Note buffers are in frames so 20 x FPS.

http://zoneminder.readthedocs.io/en/sta ... uffers-tab

Re: Trigger Function - n Time Prior

Posted: Sat Sep 10, 2016 1:22 pm
by knight-of-ni
This is by definition what the prebuffer does, and yes they work with triggers.

Re: Trigger Function - n Time Prior

Posted: Sat Sep 10, 2016 2:54 pm
by dmroeder
Oh my goodness, there it is, right in the manual! Thanks for showing me. I'm excited to try this out!

Re: Trigger Function - n Time Prior

Posted: Sat Sep 10, 2016 8:43 pm
by SteveGilvarry
RTFM FTW!!!

Re: Trigger Function - n Time Prior

Posted: Sat Sep 10, 2016 11:19 pm
by dmroeder
SteveGilvarry wrote:RTFM FTW!!!
Touché sir, touché.