zmtrigger.pl
This is an optional script that is a more generic solution to external triggering of alarms. It can handle external connections via either internet socket, unix socket or file/device interfaces. You can either use it ‘as is’ if you can interface with the existing format, or override connections and channels to customise it to your needs. The format of triggers used by zmtrigger.pl is as follows "<id>|<action>|<score>|<cause>|<text>|<showtext>" where

* 'id' is the id number or name of the ZM monitor
* 'action' is 'on', 'off', 'cancel' or ‘show’ where 'on' forces an alarm condition on, 'off' forces an alarm condition off and 'cancel' negates the previous 'on' or 'off'. The ‘show’ action merely updates some auxiliary text which can optionally be displayed in the images captured by the monitor. Ordinarily you would use 'on' and 'cancel', 'off' would tend to be used to suppress motion based events. Additionally 'on' and 'off' can take an additional time offset, e.g. on+20 which automatically 'cancel's the previous action after that number of seconds.
* 'score' is the score given to the alarm, usually to indicate it's importance. For 'on' triggers it should be non-zero, otherwise it should be zero.
* 'cause' is a 32 char max string indicating the reason for, or source of the alarm e.g. 'Relay 1 open'. This is saved in the ‘Cause’ field of the event. Ignored for 'off' or 'cancel' messages
* 'text' is a 256 char max additional info field, which is saved in the ‘Description’ field of an event. Ignored for 'off' or 'cancel' messages.
* 'showtext' is up to 32 characters of text that can be displayed in the timestamp that is added to images. The ‘show’ action is designed to update this text without affecting alarms but the text is updated, if present, for any of the actions. This is designed to allow external input to appear on the images captured, for instance temperature or personnel identity etc.

Note that multiple messages can be sent at once and should be LF or CRLF delimited. This script is not necessarily intended to be a solution in itself, but is intended to be used as ‘glue’ to help ZoneMinder interface with other systems. It will almost certainly require some customisation before you can make any use of it. If all you want to do is generate alarms from external sources then using the ZoneMinder::SharedMem perl module is likely to be easier.

Timestamp Label Format
This relates to the timestamp that is applied to each frame. It is a ‘strftime’ style string with a few extra tokens. You can add %f to add the decimal hundredths of a second to the frame timestamp, so %H:%M:%S.%f will output time like 10:45:37.45. You can also use %N for the name of the monitor and %Q which will be filled by any of the ‘show text’ detailed in the zmtriggers.pl section.

So...it is very easy to add dinamically a text on the timestamp over the image. Interface with zmtrigger.pl your external program and send a series of "<id>|show||||<showtext>" to add your own text over the image. Of course, add the %Q token in your monitor timestamp settings.

wow! Thanks Normando! Just did everything you wrote and it worked perefctly fine like that! An instruction like this should be added into the zmwiki or manual!
Btw.: It even works with Monitor-Mode (No motion detection).

Agreed, Thx Normando for a great example. Another feature that should be better defined in the Wiki LOL, At least this one is there. Let me know if you feel the inclination to work it, else I add something a bit down the road.