Now I'm getting somewhere, HA turns screen on and off :-)

fribse

Ok, finally I found the right module. So the remote module in MagicMirror (MMM-Remote-Control), and then ‘rest_command:’ setup in HA.
That way the motionsensor can turn the screen on and off in the mirror. For now I’ve made it simple with just defining four commands, two for on / off and two for dim / undim. And then just use those services in HA automations.
Works perfectly.
Now I need to turn some modules on and off depending on the time of day.

The HA commands:

rest_command:
  turn_off_mm_screen:
    url: http://IP:8080/api/monitor/off
  turn_on_mm_screen:
    url: http://IP:8080/api/monitor/on
  dim_mm_screen:
    url: http://IP:8080/api/brightness/75
  undim_mm_screen:
    url: http://IP:8080/api/brightness/100

One of the automations (at night)

- id: '1557033756115'
  alias: Turn on bathroom light at night
  trigger:
  - entity_id: binary_sensor.bathroom_movement
    from: 'off'
    platform: state
    to: 'on'
  condition:
  - after: '23:00'
    before: '7:59'
    condition: time
  - condition: state
    entity_id: light.spejl
    state: 'off'
  action:
  - data:
      brightness_pct: 10
      entity_id: light.spejl
    service: light.turn_on
  - data: {}
    service: rest_command.turn_on_mm_screen
  - data: {}
    service: rest_command.undim_mm_screen

Next step would be to modify rest_command so that I don’t have one for each action, but send a payload that is modified to the command that I want.