Persistent version of "last-changed" for the UI?

Archive Month of "What the heck?!" 2022
103

That line is how you get the data out of the template sensor again.
You can use it where you want, but if course that place needs to allow template sensors

104

What I meant; Do I need to put the line below the rest? like this

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or do I need to create a seperate sensor, like this:

  - sensor:
      - name: "test"
        state: "{{ state_attr('sensor.nominal_change_history', 'changes')['input_boolean.test'] | as_datetime }}"

and when I have multiple entities, I need to put it here twice right?

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105

It’s not part of the template to store the data, so you should not put it in that template sensor.

You should put it where you want to use the stored datetime, which can be anywhere where usage of templates is allowed

1 Like
106

Hm do you have an example? I’ve tried this one but the sensor is telling me unknown.

  - platform: template
    sensors:
      lastchangedsomfybadkamer:
        friendly_name: "Last changed SomfyBadkamer"
        value_template: >-
          state: "{{ state_attr('sensor.nominal_change_history', 'changes')['cover.somfybadkamer'] | as_datetime }}"

or is an input number (helper) a better way?

108

Not related and looks like a gpt answer?

109

I’ve seen a few spam bots on here recently, if it’s obviously not helpful it’s best just press report as spam on the post.

1 Like
112

Can I give this topic another nudge? I have a suggestion that maybe makes this more likely to be implemented:

Add two fields to the states table in the database:

  1. last_communicated_state:
    • This will normally just reflect the same value that is in state. However:
      • It can only be unknown upon sensor creation if the sensor has a state of unknown or unavailable.
      • Once the sensor has any state besides unknown or unavailable, this value will reflect that state.
      • If the sensor state ever reverts to unknown or unavailable this value will not reflect that. It will not be changed and therefore retain the previous value.
  2. last_communicated_state_change_ts
    • This will be a timestamp which changes any time the last_communicated_state has its value changed.

Having the last communicated state in the database prevents having to do lookups when a sensor gets a new state and needs to determine whether this is a “real” change or not. It is also useful in scenarios where users want to ignore unknown/unavailable and just use the last known “real” value. Also it makes it clear that there is no request to change the functionality of the existing last_changed_ts and last_updated_ts fields.

The downside is that I have no idea how much extra storage this would require adding to the database.

Also, in regards to naming of these two fields, I don’t think it matters what it is called. Here’s some other ideas for people to chew on:

  • last_known_state
  • last_monitored_state
  • last_confirmed_state
  • last_nominal_state
  • last_measured_state
  • last_state_that_is_neither_unavailable_nor_unknown
  • any_parameter_name_that_the_people_who_create_and_approve_the_PR_agree_on
  • ...
2 Likes
113

Is WTH running again this year?

It might be coming around that time to get this yearly widely requested feature raised again!

114

no

115

Ah that’s a shame, thanks for confirming though!

116

EDIT:

This has not been implemented. I posted in the wrong topic. Very sorry.

8 Likes
119

I can’t believe it, my prayers have been answered and I can finally get rid of my DIY solution! Great news!

Got my hopes up, I should have checked the link! I’m still hoping this is implemented at some point - I still have the same stance that it’s the expected behaviour from your standard HA users view.

5 Likes
121

Oops, wrong topic. Sorry about that. I meant this topic

FYI it’s 3 properties on the state object. last_changed, last_updated, and last_reported.

122

Saying that my motion sensors and door/window sensors last changed 1 minute ago because I just restarted Home Assistant is wrong 99.9% of the time.

Persisting the previous “last changed” time would be wrong 0.1% of the time.

This is not a good argument. The current behavior makes no sense, especially considering the extreme frequency of Home Assistant updates that all require restarts. This is a constant annoyance.

1 Like
123

Preaching to the choir. There’s no real argument for it.

124

I’m glad I’m not the only one realizing that. Makes it nearly impossible to accurately track the state of things like contact sensors.

125

This is longer overdue now.

3 Likes
126

How is this still not done after 4 years? If it’s really that controversial, just give us an OPTION!

If I remember correctly, someone even created this feature a couple years ago but the HA devs just blatantly refused to merge it in.

I fear that this project is getting too big to the point where management don’t care what the community wants anymore. :frowning:

If there were enough devs to support a fork of HA with some of these extra overlooked features, that would be really cool.

Ok, rant over.

I actually started updating HA less frequently because of this issue. I only update every three or four months instead of monthly.

11 Likes
127

Second that!

128

Sometimes when raising an issue you’ll hear a counter argument which will make you stop and think “Ah okay, that’s fair enough” but I still strongly disagree with any arguments against implementing this, especially as an additional attribute. Make it as clear as day if needed last_changed_excluding_restart.

Not all hope is lost though and fear not, you can restart your instance without losing that precious information… Since I raised this WFH I’ve been using this approach mentioned by TheFes which has been working perfectly. I disagree that it should be needed but it does work at least, especially when you’re in a state when you’re not adding new sensors on a regular basis.

4 Likes