Datetime calculation

Configuration
1

Hey guys!

I have a wake-up alarm configured as a datetime.

I like to trigger some automations (heating and lights) a specified time before the alarm time.

I tried a template sensor that subtracts 1hour (or a time specified in a separate datetime) from the alarm but this do not work.

Can someone tell me how to fix this or how to do it with a template trigger?


  - platform: template
    sensors:
      badheizung_startzeittest:
        friendly_name: 'badheizung_startzeittest'
        value_template: '{{ (states.input_datetime.alarm.state | timestamp_custom("%H:%M:%S")) - (states.input_datetime.badheizung_vor_wecker.state | timestamp_custom("%H:%M:%S")) }}'

Thanks in advance

2

Just do a forum search on “wake-up” to get a bazillion of examples.

1 Like
3

Hey!

thank you for your answer.
You´r right there are millions of anwers for that question, and that was the problem :slight_smile:

For now I will do it with a simple template trigger that triggers 3600 seconds before alarm (input_datetime)

{{ states('sensor.time') == (state_attr('input_datetime.alarm', 'timestamp') - 3600) |timestamp_custom('%H:%M', false) }}

thanks to the community

4

So you decided to ask the same question to add another identical answer. Interesting :joy:

5

Hey @koying !
Sorry for double asking

But I didn´t get the answer till now.
Asked for a template sensor and now is a template trigger → same function :slight_smile:

thank you

6

FYI

If you wish you can replace the reference to the sensor.time entity with now() like this:

{{ now().ctime()[11:16] == (state_attr('input_datetime.alarm', 'timestamp') - 3600) |timestamp_custom('%H:%M', false) }}
7

Thank you!

And how to use this as a sensor?

8

It could be used in a Template Binary Sensor. It would report on the moment the current time matches the input_datetime’s adjusted time (i.e. minus 3600 seconds) and off for all other times.

However it’s already suitable for use as a Template Trigger for an automation.

If the goal is to display the adjusted time in a Template Sensor, simply remove the entire left half of the equation and just use the right half.

9

Thank you so much

Yes the goal is (was) to display the time till the alarm time.
So I think of a calculation like time now minus alarm time.
Then I could use this for trigger

But this way works fine as well, just without displaying the time left

Greez from Vienna