Presence lighting in an open-plan room: dim instead of switching off

You are sitting at the dining table and behind you, in the living room, the lights go out. Technically that is correct: nobody has been there for ten minutes. It still feels like sitting in the dark, because in an open space you are looking across the whole room anyway. The standard rule of "no motion, lights off" simply does not work here.

The principle

1. Someone in a zone: that zone goes to its standard scene.
2. Zone empty, but someone elsewhere on the floor: the zone dims, for instance ceiling spots to 40 % and the rest to 30 %.
3. Someone comes back: the zone returns to its standard scene.
4. Whole floor empty: only then does everything switch off.

You keep the frugality of a short timeout this way, without anyone ever sitting in a half-dark room.

Sensors

Give every zone its own sensor: an mmWave sensor for seating, an ordinary motion sensor for the kitchen and the toilet. On top of that you need one group that says whether the floor is occupied. How to tune a sensor like that is covered in the article on the Aqara FP300.

Warn before it goes dark

When the lights are about to go out because the whole floor looks empty, give a signal first: dim or flash one light and wait thirty seconds. If anyone moves, the switch-off is cancelled and nobody noticed a thing.

- alias: Begane grond leeg
  mode: restart
  triggers:
    - trigger: state
      entity_id: binary_sensor.begane_grond_bezet
      to: 'off'
      for: '00:10:00'
  actions:
    - action: scene.turn_on
      target:
        entity_id: scene.woonkamer_gedimd
      data:
        transition: 0.4
    - wait_for_trigger:
        - trigger: state
          entity_id: binary_sensor.begane_grond_bezet
          to: 'on'
      timeout: '00:00:30'
    - if: '{{ wait.trigger is none }}'
      then:
        - action: light.turn_off
          target:
            floor_id: begane_grond
          data:
            transition: 0.4

Do not switch media off casually

Switching a light off costs nobody anything. Switching off the TV, the media player and the soundbar is considerably more intrusive, because somebody is in the middle of it. Three rules keep that liveable:

• Never switch media on from motion, only off.
• If something is playing, or paused, use a much longer timeout, say thirty minutes. A trip to the toilet should not stop the film.
• Only pause the soundbar when it is playing TV audio, not when it is grouped and playing music or radio.

Night mode

In night mode, let motion bring the lights up dimmed rather than at full brightness. That way you can find the kitchen at three in the morning without being wide awake by the time you get there.

Frequently asked questions

Why not just use a longer timeout? Because it keeps running when the floor really is empty. By dimming per zone and only switching off once everything is empty, you get a fast response and a frugal house at the same time.

Does this work with ordinary motion sensors? Yes, but then you need longer timeouts per zone, because a PIR cannot see you when you sit still. Use them for pass-through spaces like the kitchen and the toilet, and put presence sensors on the seating.

How do I set the light levels? Define them per zone in scenes ("Standard" and "Dimmed") and let your automation only call those scenes. You then adjust levels in one place. Use one fixed transition time while you are at it, so the dimming stays calm.