Sensor state (alive/unknown...)

[pctsilis (Panayiotis C Tsilis)]

• Platform information:
  • Hardware: RasPi3 (openHABian/Mysensors Ethernet GW, RFM69), TpLink HS100s, arduinos with RFM69 and various sensors.
  • OS: openhabian, version:2.4.0-1
• Issue of the topic:
  OpenHAB newbie, trying to understand how the system will show on UI if a sensor is not alive (use heartbeat, ACK, other, how?)
  Looking for tutorials, instructions, reading, help…
  Already turned ON Request heartbeat response, request ACK, Expected communication timeout, on various Mysensors things but when I turn a sensor off (cut power) the UI thing just stays at the last state.

[opus (Jürgen Baginski)]

Welcome to the openHAB Forum!

IMHO any sensor indication will remain at the last known state if you power-off the sensor .

[rossko57]

If your sensor regularly updates an openHAB Item, you may find the expire binding useful.

[vzorglub (Vincent Regaud)]

You may find this design pattern useful:

[Deprecated] Design Patterns: Generic Is Alive

There is now a Rule Template on the marketplace to implement this for you. See below for instructions on how to set it up. 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 Many sensors report status to openHAB periodically (e.g. temperature sensor) or unpredictably (e.g. motion sensors) and a subset of these sensors do not have a built in way for openHAB to query whether or not they a…

[pctsilis (Panayiotis C Tsilis)]

Thanks for qick replies everyone.
Thanks for such a great complete lesson, Vincent.
I will study it carefully, it cetainly looks like THE answer to my request.