Mysterious disappearances :
Whether you live in a suburb or a rural setting, you no doubt have been visited by the 'borrowers'.

Tools missing, jewelry, cash, mostly little things. Often you have no idea what happened, and because we're all a little daffy, we choose not to mention the event to anyone rather than start a neighborhood or family feud.

Once in a while though, you are certain of the period of time wherein the item disappeared.

If you have a good log of all sensor activity, it might be possible to check the movement of of the little angel coming and going, and the times.

Once alerted of these visits, you can change or add elements to your scripts which would be a little more attentive. A few more simple 'reed' switches on the back gate, the garage or workshop doors maybe ? You might even be able to orchestrate a little 'surprise'.

Now forewarned, you can carefully analyze the logs, and with local intelligence from your kids or other parents, it is possible to determine with reasonable certainty the only darling that could have been the culprit.

For many reasons, some parents are un-approachable, however, it's a good bet that they'd rather you come to them rather than going to the police...

It is not normally a good idea to sound alarms when outdoor PIR (passive-InfraRed) motion sensors trigger. They are generally too 'trigger-happy'. However, the log entries of their behavior can be very good information, given the behavior of other sensors at the same time.

The more sensors the better, and the more diverse types, the better.

Obviously, a single outdoor motion sensor would not by itself be very compelling evidence, but a number of PIR sensors going off in a sequence within a reasonable time is often enough information to at least know where to place any new sensors.

A good scenario might be :

You have multiple sensor types. Under-mat pressure sensors, and laser beams at waist height are generally good indicators of a solid body moving at a specific place at that time. Under driveway magnetic sensors can ascertain the presence of a vehicle.

Now the PIR sensors that you have, whether inside or outside can be reliably 'interpreted' when you put all the log entries into a 'time-homogeneous' data set

Sometimes a pet gets latched in the workshop or garage. If you see the sensor going off, and you know the door's closed, you know you might just have a trapped pet.

If however, that sensor goes off, and you know that it is not reasonable, then it is likely there's an suspicious body in that area.

Even if you aren't home at the time, you can certainly know the time of the invasion, the sequence of their movements, and thus possibly something about whether they are knowledeable of your system, ( or they're from some other neighborhood. )

Good fences make good neighbors.
A good security system keeps neighbors good.
XTension and your Macintosh make it fun.