# configuration.yaml
sensor:
  - platform: template
    sensors:
      sun_alarm_time_set:
        entity_id:
          - input_slider.sun_alarm_hour
          - input_slider.sun_alarm_min
        value_template: '{{ "%0.02d:%0.02d" | format(states("input_slider.sun_alarm_hour") | int, states("input_slider.sun_alarm_min") | int) }}'

automation:
  - alias: sun_alarm
    trigger:
      - platform: time
        minutes: "/1"
        seconds: 0
    condition:
      - condition: template
        value_template: '{{ ((now().strftime("%s") | int + 1800) | timestamp_custom("%H:%M")) == states.sensor.sun_alarm_time_set.state }}'
    action:
      - service: switch.turn_on
        entity_id: switch.sun_alarm