Finding last time an item was a certain value

[auzick (Andy Uzick)]

Is there a reasonable way to discover what time a given item’s state as a specific value? I looked at the persistence docs and didn’t see a solution.

My specific use case is, I want a rule to turn off a light at midnight, but only if there was no motion detected in the room in the last 2 hours. So I need to find out what time a motion sensor’s state was changed to “1”.

[rossko57]

You don’t even need persistence. It’s very common to use an associated separate timestamp Item for this purpose, for key Items.
There’s even a channel profile to make that easier.

Or you can use persistence with previousState(true), and examine the timestamp of the object returned.

Complex motion/presense rule/s?

You can get this information through Persistence. When you call MyItem.previousState(true) it will return a HistoricState Object which includes a timestamp (.getTimestamp) and the state (.state). By passing true to the call it will return the previous state that is different from the current state. You can then check the timestamp to see how long ago it is. This works great as long as your “since” is greater than half a second or so. It takes time to save the states to the database. Except wh…