DeltaLux

A Home Assistant integration for light groups with brightness offsets.

Why?

You have multiple lights in a room and want them to dim together while maintaining their relative brightness. Your accent lights should stay 25% dimmer than the main lights.

DeltaLux lets you set a brightness offset for each light in a group. When you dim the group, the relationships persist automatically.

Requires Home Assistant 2024.4 or newer.

Features

• Persistent brightness offsets between lights
• Per-light minimum and maximum brightness constraints
• Absolute or relative offset modes
• Full color support: color temperature (Kelvin), HS/RGB/RGBW/RGBWW/XY, and white mode
• Effects, flash, and transitions forwarded to member lights
• Supported color modes and effects aggregated from the members — mixed groups (e.g. a dimmer plus color bulbs) work correctly
• Master brightness survives restarts and off/on cycles
• Set up through the UI or YAML import, fully editable afterwards

Installation

1. In your Home Assistant config directory, create the folder custom_components/deltalux/
2. Copy the contents of this repository into that folder
3. Restart Home Assistant
4. Go to Settings → Devices & Services → Add Integration
5. Search for "DeltaLux"

Setup

GUI

1. Choose Setup with GUI
2. Name your group and select the lights to include (at least 2)
3. Choose the offset type — absolute or relative
4. Set each light's offset (-100 to +100) and, if needed, its min/max brightness (1–100%)

YAML

Choose Import from YAML and paste your config:

name: Living Room
offset_type: absolute
lights:
  - entity_id: light.ceiling
    offset: 0
    min_brightness: 1
    max_brightness: 100
  - entity_id: light.floor_lamp
    offset: -20
    min_brightness: 5
    max_brightness: 100
  - entity_id: light.accent
    offset: -40
    min_brightness: 2
    max_brightness: 80

offset is required per light; min_brightness and max_brightness are optional (defaults 1 and 100).

Group names must be unique, and a DeltaLux group cannot contain another DeltaLux group.

Editing a group

Go to Settings → Devices & Services → DeltaLux → Configure. Three options:

• Add or remove lights — change group membership; newly added lights get their own offset settings
• Adjust brightness settings — change the offset type and each light's offset and min/max
• View/Edit as YAML — edit the full configuration as YAML

Offset Modes

Absolute (default): Offset in percentage points

• Master at 50%, offset -25 → light at 25%
• Master at 100%, offset -25 → light at 75%

Relative: Offset as a multiplier

• Master at 100%, offset -25 (0.75x) → light at 75%
• Master at 80%, offset -25 (0.75x) → light at 60%

Positive offsets make a light brighter than the master. In both modes the result is clamped to the light's min/max brightness.

Min/Max

Set min/max to keep lights inside their useful range:

• Min at 5% prevents LED strips from flickering
• Max at 70% keeps accent lights from overpowering the room

Behavior Notes

• The group is on if any member is on, and unavailable only if no members are available.
• Changing color or effect on an already-lit group does not touch member brightness — only an explicit brightness change (or turning the group on) recalculates offset levels.
• A member that is off when the group is turned on comes back at its offset level.
• Turning the group off keeps the master brightness, so the next turn-on restores every light to its previous level.
• Color state shown on the group mirrors a color-capable member, so a brightness-only bulb can't blank out the group's color attributes.
• The group entity exposes master_brightness and per-light offsets as state attributes for use in automations.

License

MIT