Help with automation: Linking 2 bulbs' attributes

Configuration
1

Hello everyone,

I’m trying to link 2 bulbs to eachothers attributes, starting with brightness (1 is a simulated bulb, the other a wifi bulb).
The idea is when one of the 2 changes brightness, the other get its brightness updated.
However it doesn’t seem to work… Both bulbs won’t update. What am I missing here?

- alias: Bedroom brightness link
  initial_state: 'on'
  trigger:
    - platform: template
      value_template: '{{ states.light.slaapkamer.attributes.brightness }}'
    - platform: template
      value_template: '{{ states.light.bedroom_light.attributes.brightness }}'   
  condition:
    - condition: template
      value_template: '{{ not is_state_attr("light.slaapkamer", "brightness", "(states.light.bedroom_light.attributes.brightness)") }}'
  action:
    - service: light.turn_on
      data_template:
        entity_id: >-
          {% if ('trigger.entity_id.attributes.friendly_name' == 'Slaapkamer') %}
            light.bedroom_light
          {% else %}
            light.slaapkamer
          {% endif %}
        brightness: >-
          {% if ('trigger.entity_id.attributes.friendly_name' == 'Slaapkamer') %}
            {{ states.light.bedroom_light.attributes.brightness }}
          {% else %}
            {{ states.light.slaapkamer.attributes.brightness }}
          {% endif %}
2

Anyone have an idea, please? :blush:

3

Try simple state triggers, no to or from and then a condition check to see if the brightness has changed. Right now you’re not doing any comparison in the trigger, so it’ll never be true or false.

  trigger:
    - platform: state
      entity_id: light.slaapkamer
    - platform: state
      entity_id: light.bedroom_light   
  condition:
    - condition: template
      value_template: '{{ trigger.to_state.attributes.brightness != trigger.from_state.attributes.brightness }}'
  action:
1 Like
4

Doesn’t that also perform the action when the lights turn off?
And it’s possible the state doesn’t change, only the attributes. The lights are already on, but only brightness is changing.

5

Worth reading the state trigger docs:

Triggers when the state of a given entity changes. If only entity_id is given trigger will activate for all state changes, even if only state attributes change

The condition I wrote will cover any change in brightness, which probably will include turning the light on or off. I’ve never tested it though, because I’ve never needed that kind of automation.

6

Yes, you were right. Thanks!