Accent & Signal Light — Home Assistant Integration

Accent & Signal Light is a Home Assistant custom integration that lets you manage accent and notification lights without writing complex bookkeeping automations. Instead of tracking "which automation last changed the colour of my lamp" across dozens of rules, Accent & Signal Light gives every use-case its own named slot in a priority-sorted stack or queue. When a slot is cleared the light automatically reverts to the next lower layer — zero cleanup automation required.

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Table of contents

1. Concepts — the three-layer model
2. Installation
3. Configuration
4. Entities created
5. Services reference
6. Example automations
7. Architecture notes

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1. Concepts — the three-layer model

Accent & Signal Light wraps a single physical light entity (or light group) in a three-layer priority model. Layers are evaluated from highest to lowest; the topmost non-empty layer controls the physical light.

┌───────────────────────────────────────────────────────────┐
│  SIGNAL LAYER  (highest priority)                         │
│  Priority queue of named signals.                         │
│  Highest-priority signal controls the light.              │
│  When cleared, next signal takes over (or falls through). │
├───────────────────────────────────────────────────────────┤
│  ACCENT LAYER  (medium priority)                          │
│  Priority stack of named accents.                         │
│  Highest-priority accent controls the light when no       │
│  signal is active.                                        │
│  When cleared, next accent takes over (or falls through). │
├───────────────────────────────────────────────────────────┤
│  BASE LAYER    (lowest priority)                          │
│  Default light state — on/off, colour, brightness.        │
│  Exposed as a standard HA light entity.                   │
│  Active only when accent and signal layers are empty.     │
└───────────────────────────────────────────────────────────┘
         │
         ▼ controls
   ┌──────────────┐
   │ Physical     │
   │ light entity │
   └──────────────┘

Base layer

The base layer is the "ambient" default. Set it once (e.g. warm white at 40 % brightness) and it will be applied whenever nothing else is active. It is exposed as a standard light entity, so you can control it from dashboards, voice assistants, or automations exactly like any other light.

Accent layer

Accents are long-lived overrides — for example:

Accent name	Priority	Use-case
holiday_4th	20	Red/white/blue all week
movie_mode	60	Dim warm light when the TV is on
party	80	Colour cycle while the party playlist plays

Multiple accents can coexist. The one with the highest priority controls the light. When you clear party, movie_mode (if still present) takes over immediately — no extra automation needed. If the base light is off, accents are still tracked but they will not turn the physical light on by themselves.

Accents are added/removed via the signal_light.set_accent and signal_light.clear_accent services.

Signal layer

Signals are short-lived notifications — for example:

Signal name	Priority	Use-case
doorbell	90	Flash white when someone rings the bell
laundry_done	70	Slow blue pulse when the washing is finished
timer_expired	80	Red flash when a kitchen timer ends

The highest-priority active signal overrides the accent and base layers. When it is cleared (e.g. the user acknowledges the doorbell) the next signal (if any) takes over, or the accent/base layer resumes. If the base light is off, signals remain queued and only turn the light on when their priority is greater than the configured signal wake priority.

Signals are added/removed via the signal_light.set_signal and signal_light.clear_signal services.

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2. Installation

HACS (recommended)

1. Open HACS → Integrations → ⋮ → Custom repositories.
2. Add https://github.com/arkane-systems/ha-accent-signal-light as an Integration repository.
3. Search for Accent & Signal Light and click Download.
4. Restart Home Assistant.

Manual

1. Copy the custom_components/signal_light/ directory into your HA configuration directory under custom_components/.
2. Restart Home Assistant.

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3. Configuration

1. Go to Settings → Devices & Services → Add Integration.
2. Search for Accent & Signal Light and click it.
3. Fill in the form:
   • Name — a label for this instance (e.g. "Living Room Accent & Signal Light").
   • Underlying light entity — the light.* entity that Accent & Signal Light will control (may be a light group).
   • Signal wake priority — signals must have a priority greater than this value to turn the light on while the base layer is off.
4. Click Submit.

You can create multiple Accent & Signal Light instances — one per physical light or group you want to manage this way.

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4. Entities created

Each Accent & Signal Light instance creates five entities, all grouped under a single HA device named after the instance.

Entity type	Name suffix	Description
light	Base	Base-layer light — controls the default state.
sensor	Active Signal	Name of the top-priority signal, or "none".
sensor	Active Accent	Name of the top-priority accent, or "none".
sensor	Signal Queue	Count of queued signals; full queue in attrs.
sensor	Accent Stack	Count of stacked accents; full stack in attrs.

Base light entity

The base light (light.<name>_base) behaves like any standard HA light. Use it in dashboards or automations to set the default ambient state. Note that its reported state always reflects the base layer, even when an accent or signal is overriding the physical light.

Sensor entities

All sensor entities report their data as both state and extra_state_attributes.

Active Signal / Active Accent sensors:

state:       "doorbell"
attributes:
  priority:  90
  hs_color:  [0, 0]
  brightness: 255

Signal Queue / Accent Stack sensors:

state:    2
attributes:
  queue:
    - name:     "doorbell"
      priority: 90
      attrs:    {hs_color: [0, 0], brightness: 255}
    - name:     "laundry_done"
      priority: 70
      attrs:    {hs_color: [240, 80], brightness: 128}

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5. Services reference

All services are in the signal_light domain and target the base-layer light entity (or its device) of the instance you want to control.

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signal_light.set_signal

Add or update a signal in the priority queue. If a signal with the given name already exists it is replaced (handy for updating colour without a separate clear).

Field	Type	Required	Default	Description
entity_id	entity	✓	—	The base-layer light of the target instance
signal_name	string	✓	—	Unique name for this signal
priority	integer	—	50	Higher values take precedence
brightness	integer	—	—	0–255
brightness_pct	float	—	—	0–100 %
color_name	string	—	—	Named colour (e.g. "red")
hs_color	list	—	—	[hue, saturation]
rgb_color	list	—	—	[r, g, b]
color_temp_kelvin	int	—	—	Kelvin (1000–10000)
effect	string	—	—	Effect name
transition	float	—	—	Seconds

---

signal_light.clear_signal

Remove a signal from the priority queue.

Field	Type	Required	Description
entity_id	entity	✓	The base-layer light
signal_name	string	✓	Name of the signal to remove

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signal_light.set_accent

Add or update an accent in the priority stack.

Field	Type	Required	Default	Description
entity_id	entity	✓	—	The base-layer light of the target instance
accent_name	string	✓	—	Unique name for this accent
priority	integer	—	50	Higher values take precedence
brightness	integer	—	—	0–255
brightness_pct	float	—	—	0–100 %
color_name	string	—	—	Named colour (e.g. "red")
hs_color	list	—	—	[hue, saturation]
rgb_color	list	—	—	[r, g, b]
color_temp_kelvin	int	—	—	Kelvin (1000–10000)
effect	string	—	—	Effect name
transition	float	—	—	Seconds

---

signal_light.clear_accent

Remove an accent from the priority stack.

Field	Type	Required	Description
entity_id	entity	✓	The base-layer light
accent_name	string	✓	Name of the accent to remove

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6. Example automations

Door-bell flash

# Turn the living-room signal light white when the doorbell is pressed.
# The flash lasts until the automation clears it (e.g. after 30 s).
automation:
  - alias: "Doorbell: signal on"
    trigger:
      - platform: state
        entity_id: binary_sensor.doorbell
        to: "on"
    action:
      - service: signal_light.set_signal
        target:
          entity_id: light.living_room_signal_light_base
        data:
          signal_name: doorbell
          priority: 90
          hs_color: [0, 0]   # white
          brightness: 255

  - alias: "Doorbell: signal off after 30 s"
    trigger:
      - platform: state
        entity_id: binary_sensor.doorbell
        to: "on"
        for: "00:00:30"
    action:
      - service: signal_light.clear_signal
        target:
          entity_id: light.living_room_signal_light_base
        data:
          signal_name: doorbell

4th of July accent

# Apply a patriotic accent at midnight starting July 1st (i.e. the very
# beginning of July 1st) and remove it at midnight starting July 5th
# (i.e. the very beginning of July 5th, so the accent is active through
# the end of July 4th).  Any higher-priority accents or signals still take
# precedence.
automation:
  - alias: "4th of July accent: activate"
    trigger:
      - platform: time
        at: "00:00:00"
    condition:
      - condition: template
        value_template: "{{ now().month == 7 and now().day == 1 }}"
    action:
      - service: signal_light.set_accent
        target:
          entity_id: light.living_room_signal_light_base
        data:
          accent_name: fourth_of_july
          priority: 20
          rgb_color: [255, 0, 0]   # start red; rotate via separate automation

  - alias: "4th of July accent: deactivate"
    trigger:
      - platform: time
        at: "00:00:00"
    condition:
      - condition: template
        value_template: "{{ now().month == 7 and now().day == 5 }}"
    action:
      - service: signal_light.clear_accent
        target:
          entity_id: light.living_room_signal_light_base
        data:
          accent_name: fourth_of_july

Movie mode accent

# Activate movie-mode (dim, warm) while the TV is on.  Because this has a
# higher priority than the holiday accent, it overrides it during movie time.
automation:
  - alias: "Movie mode: activate"
    trigger:
      - platform: state
        entity_id: media_player.living_room_tv
        to: "playing"
    action:
      - service: signal_light.set_accent
        target:
          entity_id: light.living_room_signal_light_base
        data:
          accent_name: movie_mode
          priority: 60
          brightness: 40
          color_temp_kelvin: 2700

  - alias: "Movie mode: deactivate"
    trigger:
      - platform: state
        entity_id: media_player.living_room_tv
        to: "idle"
      - platform: state
        entity_id: media_player.living_room_tv
        to: "off"
    action:
      - service: signal_light.clear_accent
        target:
          entity_id: light.living_room_signal_light_base
        data:
          accent_name: movie_mode

Dashboard visibility

Add the four sensor entities to a dashboard card to see what is currently active at a glance:

type: entities
title: Living Room Accent & Signal Light
entities:
  - entity: light.living_room_signal_light_base
  - entity: sensor.living_room_signal_light_active_signal
  - entity: sensor.living_room_signal_light_active_accent
  - entity: sensor.living_room_signal_light_signal_queue
  - entity: sensor.living_room_signal_light_accent_stack

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7. Architecture notes

Coordinator

The integration uses a custom SignalLightCoordinator (not HA's built-in DataUpdateCoordinator, which is designed for polling). The coordinator owns all mutable state and is the single place where state transitions happen.

Entities register a _remove_listener callback in async_added_to_hass and de-register in async_will_remove_from_hass. The coordinator calls all listeners after every mutation, triggering a write_ha_state on each entity.

Priority ordering

Both the accent stack and signal queue are stored as Python lists sorted by priority descending. Insertion and deletion are O(n) — entirely adequate for the expected number of entries (typically < 10). The name field acts as a primary key: setting an existing name replaces the entry.

State restoration

The base-layer light entity extends RestoreEntity. On startup it reads its previous state from the HA recorder and re-applies it to the coordinator, ensuring the base layer survives restarts.

Accent and signal layers are intentionally not persisted. They are expected to be re-populated by automations (e.g. via homeassistant.start triggers). This avoids stale signals lingering after a restart.

Physical-light control

Every time any layer changes, _async_apply_state() is called. It evaluates the effective state top-down and calls light.turn_on or light.turn_off on the underlying entity. The call is made with blocking=True to ensure the light state is consistent before listeners are notified. When the base layer is off, accents never wake the light and only signals above the configured wake priority may do so; queued accents/signals still take effect immediately once the base layer is turned back on.

On startup, if the underlying light is not yet available, apply calls are deferred. The coordinator listens for the underlying entity becoming available and re-applies the effective state once it comes online.

Before any turn_on call, color descriptors are normalized so only one of color_name, hs_color, rgb_color, rgbw_color, rgbww_color, xy_color, or color_temp_kelvin is sent in the payload.

Capability mirroring

The base-layer light mirrors capability metadata from the underlying light so UI controls stay aligned with the real hardware/group:

• supported_color_modes
• supported_features
• effect_list
• min_color_temp_kelvin / max_color_temp_kelvin

Entity services

The four signal_light.* services are registered as entity services on the light platform. This means:

• HA validates the entity_id / device_id target automatically.
• The service is routed to async_handle_set_signal / etc. on the matching SignalBaseLight entity.
• Multiple instances are fully isolated — calling the service with one instance's entity_id never affects another.