HomeAssistant Blueprint to toggle scenes

toggle-scene.yaml

blueprint:
  name: Toggle Scenes
  description:
    Trigger this automation from another automation using This will allow
    you to use a single trigger to toggle a scene on or off. A timeout variable is
    given, after which the trigger will activate the scene irrespective of the state
    of the last toggle.
  domain: automation
  input:
    scene_input:
      name: Scene to be toggled
      description: This is the scene that will be turned on and off
      selector:
        entity:
          domain:
            - scene
          multiple: false
    no_scene_wait:
      name: Timeout
      description:
        The time after which the original scene will be activated even
        if the next toggle state would have been scene off
      default: 240
      selector:
        number:
          min: 0.0
          max: 3600.0
          unit_of_measurement: minutes
          step: 1.0
          mode: slider
    scene_transition:
      name: Transition Time
      description: The transition time for changing scenes
      default: 2.5
      selector:
        number:
          mode: box
          min: 0
          max: 600
          step: 0.1
          unit_of_measurement: seconds
trigger_variables:
  scene_entity: !input scene_input
  scene_transition: !input scene_transition
  scene_store_name: "{{scene_entity.split('.')[1] + '_store_previous_state'}}"
  scene_store_entity: "{{'scene.' + scene_store_name}}"
  time_out_seconds: !input no_scene_wait
  time_out: "{{time_out_seconds*60}}"
trigger:
  - platform: event
    event_type: scene_toggle
    event_data:
      entity_id: "{{scene_entity}}"
action:
  if:
    - condition: template
      value_template: "

        {{(states(scene_store_entity) == 'unknown') or (0 < as_timestamp(states(scene_store_entity),0)
        - as_timestamp(states(scene_entity),0)) or (as_timestamp(now()) - as_timestamp(states(scene_entity),0)
        > time_out)}}"
      alias:
        If film_before activated more recently than film mode or if film mode has
        not been activated for more than 4 hours
  then:
    - service: scene.create
      data:
        scene_id: "{{scene_store_name}}"
        snapshot_entities: "{{ state_attr(scene_entity, 'entity_id') }}"
    - if:
        - condition: template
          value_template: "{{(states(scene_store_entity) == 'unknown')}}"
          alias: If scene before has never been activated before
      then:
        - service: scene.turn_on
          data:
            transition: >
              {% if trigger.event is defined %}
                {{trigger.event.data.transition | default(scene_transition)}}
              {% else %}
                {{scene_transition}}
              {% endif %}
          target:
            entity_id: "{{scene_store_entity}}"
    - service: scene.turn_on
      target:
        entity_id: "{{scene_entity}}"
      data:
        transition: >
          {% if trigger.event is defined %}
            {{trigger.event.data.transition | default(scene_transition)}}
          {% else %}
            {{scene_transition}}
          {% endif %}
  else:
    - service: scene.turn_on
      data:
        transition: >
          {% if trigger.event is defined %}
            {{trigger.event.data.transition | default(scene_transition)}}
          {% else %}
            {{scene_transition}}
          {% endif %}
      target:
        entity_id: "{{scene_store_entity}}"

Added transition time. You can set a default or pass it along with the event trigger.