Timestamp whenever an item changes state

[bernard (Bernardo Lopes)]

Hello community,

I am new in OpenHAB and i have a question,

Is it possible to save in a text file, the date when a certain item, for example a switch, changes its state? Would it be something implemented in a rule?

Thank you

[hafniumzinc (T)]

Does it have to be in a text file? What’s it for?

You can use Persistence to store the state of a switch.

Or you could use another Item which follows your switch Item, and sets itself to a timestamp of the last update:

Design Pattern: Time of Last Update

Please see Design Pattern: What is a Design Pattern and How Do I Use Them for a description of what Design Patterns are and how to use them. Problem Statement Sometimes you want to know the latest time when an item has been updated. For example, when was the last time the front door was opened, or when was the last temperature reading from your fridge. It’s very useful for battery powered devices to check that they still are alive. Concept By using the new profile functionality for items (in …

[bernard (Bernardo Lopes)]

Hello hafniumzinc,

It doesn’t need to be a text file. What I want is to save the exact moment when an item changes state. In the case of an item switch, I want to save the timestamp of the change from ON to OFF and OFF to ON. That is, whenever there is a change of state.

Thank you.

[hafniumzinc (T)]

If you are on OH3 then this is already happening

Persistence

[bernard (Bernardo Lopes)]

Thank you, I’ll check it out!

[rossko57]

Note that the default persistence service (rrd4j) does some averaging by default; as time goes by the time periods get bigger grained. Okay for approximate times over the last week, no good for second-by-second accuracy. Other persistence services bring other options.