Detecting Non- reporting Sensors

I am looking for suggestions for methods to detect when a sensor stops reporting. OpenHAB is managing my security system. I have 10 to 15 door sensors, window sensors, heat detectors…yadda, yadda, yadda. They all report when something changes but also, they all report a kind of “I’m alive” about every 70 minutes. They are not synchronized and I think there is some jitter in case they might overlap.
What I would like to do is detect if a sensor stops these “I’m alive” reports (like because of a dead battery). I have experimented with a few methods but they rapidly become cumbersome and unwieldy.
For example, I created new DateTime items for each sensor and “store” the last time it reported in the item State. Then I think I should cycle through them every, say 80 minutes and note any that didn’t report during that interval. But I don’t know of a way to do that.

Does anybody have any suggestions about how I could do that? Or suggest a better way all together?


Beautiful. This looks like exactly what I need.
I had a feeling the community had a solution.
I should have asked before I experimented.
Thanks again (as usual)