aurora.yaml

alias: Aurora Borealis
sequence:
  - variables:
      light: {{light | default(light.default_lamp) }}
      start_time: '{{ now() | as_timestamp }}'
      hue_lim:
        - 120
        - 290
      wavelength: 30
      amplitude: '{{(hue_lim[1] - hue_lim[0])/2}}'
  - repeat:
      while:
        - condition: template
          value_template: '{{ true }}'
      sequence:
        - variables:
            offset: "{{ (now() | as_timestamp) - (start_time | float) }}"
            hue: >-
              {{ sin(offset/wavelength*2*3.14)*amplitude + amplitude +
              hue_lim[0]}}
        - service: light.turn_on
          data:
            hs_color: '{{ [hue|float, 100] }}'
            transition: 1
            entity_id: '{{ light }}'
        - delay: '1'
mode: single