How to check time between 2 events

[vzorglub (Vincent Regaud)]

Check this.
This is exactly what you are trying to do:

Generic Presence Detection

Edit: A rewrite to take advantage of the Debounce rule template on the marketplace. This is a tutorial to show a generic and sensor independent way to do presence detection with multiple sensors and implementing anti-flapping (i.e. all sensors must be OFF for a certain amount of time before the home goes to away). Requirements One or more Switches determines whether someone is present. If one or more of these Switches is ON then someone is presumed to be present (more complex algorithms are …