Loosely based on a Gist by Claudio Bartoli

This app is a basic approach to dimming lights with Ikea Trädfri switches. On the round switch it uses the "brighter" and "darker" buttons, on the square one it uses "O" and "I". A short press on "brighter" or "I" will switch the light on, a press on "darker" or "O" will switch it off. If you hold "brighter" or "I" the light will dim UP, holding "darker" or "0" will dim it down. It's a simple app but works fine for me. I reduced the original three files to one. Considering this is my first Python script there will probably be errors in it, feel free to let me know.

The repository can be added to HACS. If you don't know what that is, this script probably is not for you...

• Multiple lights can be added for a dimmer, they will be dimmed individually. Adding groups is not possible as they do not report back brightness.
• Add the remote name and the type, either "ROUND" or "SQUARE"
• You can set minimum and maximum values for dimming which will be applied to all lights connected to the dimmer. Absolute minimum is 0, the maximum is 255.
• The dimmer is updating values (about) every half second. The step size determines how fast dimming is.

---
  remote_aanrecht_brightness:
    module: tradfri
    class: TradfriRemoteDimmer
    lights:
      - light.inbouwspots_aanrecht_keuken
      - light.ledstrip_aanrecht_keuken
    remote:
      id: tradfri_remote_control
      type: ROUND
    dimmer:
      step: 10
      min: 0
      max: 255

  remote_bureau_brightness:
    module: tradfri
    class: TradfriRemoteDimmer
    lights:
      - light.pendel_bureau
      - light.inbouwspots_bureau
      - light.opbouwspots_bureau
    remote:
      id: tradfri_on_off_switch
      type: SQUARE
    dimmer:
      step: 10
      min: 0
      max: 255