Set light brightness with variable

[lexlex]

Hi guys. I have a little problem and need some help.

I want to set the brightness of a light entity with a variable. However it always throws an error and I can’t understand it.

Here is the error message:

This is how I set the variable under actions:

variables:
  initial_brightness: >-
    {{ (100 / 255 * state_attr('light.bathroom_lights', 'brightness')) |
    round(0) }}

And this is how I want to set the brightness of the light entity:

alias: Reset brightness if lights are on
if:
  - condition: device
    type: is_on
    device_id: 304b64c5e900bfe731168467dd096990
    entity_id: cae3bc1dbb14c4fc2fd717a3b218f1d2
    domain: light
then:
  - action: light.turn_on
    metadata: {}
    data:
      brightness_pct: "{{ initial_brightness }}"
    target:
      entity_id: light.bathroom_lights

I’ve followed the variables docs from HA but nothing helps. Would really appreciate if someone could give me a hint.

Thanks

[Edwin_D]

The second bit looks like a script(but not quire either)? If so, then you should pass the data to the script when calling.

  action: script.reset_brightness_if_lights_are_on
  data:
    initial_brightness: "{{ initial_brightness }}"

If not, you should show more of your yaml. Most likely the variable is defined in a different scope, and therefore undefined in the place where you use it.

[lexlex]

Hi Edwin_D, thanks for your reply. Here is the partially full yaml. I’ve cut the rest at the end.

YAML:

Summary

alias: Turn on Bathroom Lights by Motion
description: ""
triggers:
  - type: motion
    device_id: e6643a3eaeb54fea6d4195dd86fce4ee
    entity_id: d51c9a2e90480a8d566d0a943968820f
    domain: binary_sensor
    trigger: device
conditions: []
actions:
  - alias: Reset brightness if lights are on
    if:
      - condition: device
        type: is_on
        device_id: 304b64c5e900bfe731168467dd096990
        entity_id: cae3bc1dbb14c4fc2fd717a3b218f1d2
        domain: light
    then:
      - action: light.turn_on
        metadata: {}
        data:
          brightness_pct: "{{ initial_brightness }}"
        target:
          entity_id: light.bathroom_lights
  - action: notify.mobile_app_pixel_8_pro
    metadata: {}
    data:
      title: 💡 auto turn off
      message: clear_notification
      data:
        tag: BathroomLightsOff
        channel: Toasts
        progress: -1
        progress_max: 10
    alias: Clear grace period progress notification
  - alias: Set Natural Light Scene if lights are off
    if:
      - condition: device
        type: is_off
        device_id: 304b64c5e900bfe731168467dd096990
        entity_id: cae3bc1dbb14c4fc2fd717a3b218f1d2
        domain: light
    then:
      - action: scene.turn_on
        metadata: {}
        data: {}
        target:
          entity_id: scene.bathroom_lights_natural_light
        enabled: true
  - alias: Wait for Sensor stopped detecting motion for 50s
    wait_for_trigger:
      - type: no_motion
        device_id: e6643a3eaeb54fea6d4195dd86fce4ee
        entity_id: d51c9a2e90480a8d566d0a943968820f
        domain: binary_sensor
        trigger: device
        for:
          hours: 0
          minutes: 0
          seconds: 50
  - variables:
      initial_brightness: >-
        {{ (100 / 255 * state_attr('light.bathroom_lights', 'brightness')) |
        round(0) }}
mode: restart 

[Edwin_D]

@lexlex

 - variables:
      initial_brightness: >-
        {{ (100 / 255 * state_attr('light.bathroom_lights', 'brightness')) |
        round(0) }}

Variables should not lt be part of the action array (note the - before it) but a level higher I think.

Also, if the light is off, the template will throw an error. It is likely that is what you are testing for (I can’t tell because of those wretched device conditions), but the template is evaluated when the light is off too. So I’d also add a | float(0) to it to prevent the error.

The automation trace should show the variable values, though you might need to download the trace json to see it.

[lexlex]

I’ve looked at the documentation here and they say that the variables in the variables action can be templated.

I’ve also added the “float(0)” as you said but the error still persists.

First run when lights are off. Variable gets set properly:

Second run, when lights are on but with a different brightness level. The variable should set the brightness to the previous state:

[Mayhem_SWE (Magnus Helin)]

Obviously you cannot use the variable before it exists.
Variables are not retained between automation runs.

[lexlex]

thank you for the tip! I thought they will be retained. I’ve created a Number Helper now and it works flawless.