Automation Trigger


Triggers are what starts the processing of an automation rule. It is possible to specify multiple triggers for the same rule - when any of the triggers becomes true then the automation will start. Once a trigger starts, Home Assistant will validate the conditions, if any, and call the action.

Event trigger

Triggers when an event is being processed. Events are the raw building blocks of Home Assistant. You can match events on just the event name or also require specific event data to be present.

Events can be fired by components or via the API. There is no limitation to the types. A list of built-in events can be found here.

automation:
  trigger:
    platform: event
    event_type: MY_CUSTOM_EVENT
    # optional
    event_data:
      mood: happy

Starting 0.42, it is no longer possible to listen for event homeassistant_start. Use the ‘homeassistant’ platform below instead.

Home Assistant trigger

Triggers when Home Assistant starts up or shuts down.

automation:
  trigger:
    platform: homeassistant
    # Event can also be 'shutdown'
    event: start

MQTT trigger

Triggers when a specific message is received on given topic. Optionally can match on the payload being sent over the topic. The default payload encoding is ‘utf-8’. For images and other byte payloads use encoding: '' to disable payload decoding completely.

automation:
  trigger:
    platform: mqtt
    topic: living_room/switch/ac
    # Optional
    payload: 'on'
    encoding: 'utf-8'

Numeric state trigger

Triggers when numeric value of an entity’s state crosses a given threshold. On state change of a specified entity, attempts to parse the state as a number and triggers once if value is changing from above to below or from below to above the given threshold.

automation:
  trigger:
    platform: numeric_state
    entity_id: sensor.temperature
    # Optional
    value_template: '{{ state.attributes.battery }}'
    # At least one of the following required
    above: 17
    below: 25

    # If given, will trigger when condition has been for X time, can also use days and milliseconds.
    for:
      hours: 1
      minutes: 10
      seconds: 5

Listing above and below together means the numeric_state has to be between the two values. In the example above, a numeric_state that goes to 17.1-24.9 (from 17 or below, or 25 or above) would fire this trigger.

The for: can also be specified as HH:MM:SS like this:

automation:
  trigger:
    platform: numeric_state
    entity_id: sensor.temperature
    # Optional
    value_template: '{{ state.attributes.battery }}'
    # At least one of the following required
    above: 17
    below: 25

    # If given, will trigger when condition has been for X time.
    for: '01:10:05'

State trigger

Triggers when the state of a given entity changes. If only entity_id is given trigger will activate for all state changes, even if only state attributes change.

automation:
  trigger:
    platform: state
    entity_id: device_tracker.paulus, device_tracker.anne_therese
    # Optional
    from: 'not_home'
    # Optional
    to: 'home'

    # If given, will trigger when state has been the to state for X time.
    for: '01:10:05'

Use quotes around your values for from and to to avoid the YAML parser interpreting values as booleans.

Sun trigger

Sunset / Sunrise trigger

Triggers when the sun is setting or rising, i.e. when the sun elevation reaches 0°.

An optional time offset can be given to have it trigger a set time before or after the sun event (e.g. 45 minutes before sunset).

Since the duration of twilight is different throughout the year, it is recommended to use sun elevation triggers instead of sunset or sunrise with a time offset to trigger automations during dusk or dawn.

automation:
  trigger:
    platform: sun
    # Possible values: sunset, sunrise
    event: sunset
    # Optional time offset. This example will trigger 45 minutes before sunrise.
    offset: '-00:45:00'

Sun elevation trigger

Sometimes you may want more granular control over an automation than simply sunset or sunrise and specify an exact elevation of the sun. This can be used to layer automations to occur as the sun lowers on the horizon or even after it is below the horizon. This is also useful when the “sunset” event is not dark enough outside and you would like the automation to run later at a precise solar angle instead of the time offset such as turning on exterior lighting. For most things intended to trigger during dusk or dawn, a number between 0° and -6° is suitable; -4° is used in this example:

automation:
  alias: "Exterior Lighting on when dark outside"
  trigger:
    platform: numeric_state
    entity_id: sun.sun
    value_template: "{{ state.attributes.elevation }}"
    # Can be a positive or negative number
    below: -4.0
  action:
    service: switch.turn_on
    entity_id: switch.exterior_lighting

If you want to get more precise, start with the US Naval Observatory tool which will help you estimate what the solar elevation will be at any specific time. Then from this, you can select from the defined twilight numbers.

Although the actual amount of light depends on weather, topography and land cover, they are defined as:

  • Civil twilight: 0° > Solar angle > -6°

    This is what is meant by twilight for the average person: Under clear weather conditions, civil twilight approximates the limit at which solar illumination suffices for the human eye to clearly distinguish terrestrial objects. Enough illumination renders artificial sources unnecessary for most outdoor activities.

  • Nautical twilight: 6° > Solar angle > -12°
  • Astronomical twilight: 12° > Solar angle > -18°

A very thorough explanation of this is available in the Wikipedia article about the Twilight.

Template trigger

Template triggers work by evaluating a template on every state change for all of the recognized entities. The trigger will fire if the state change caused the template to render ‘true’. This is achieved by having the template result in a true boolean expression ({{ is_state('device_tracker.paulus', 'home') }}) or by having the template render ‘true’ (example below). Being a boolean expression the template must evaluate to false before it will fire again. With template triggers you can also evaluate attribute changes by using is_state_attr ({{ is_state_attr('climate.living_room', 'away_mode', 'off') }})

automation:
  trigger:
    platform: template
    value_template: "{% if is_state('device_tracker.paulus', 'home') %}true{% endif %}"

Rendering templates with time (now()) is dangerous as trigger templates only update based on entity state changes.

Time trigger

The time trigger is configured to run once at a specific point in time each day.

automation:
  trigger:
    platform: time
    # Military time format. This trigger will fire at 3:32 PM
    at: '15:32:00'

Time pattern trigger

With the time pattern trigger, you can match if the hour, minute or second of the current time matches a specific value. You can prefix the value with a / to match whenever the value is divisible by that number. You can specify * to match any value.

automation:
  trigger:
    platform: time_pattern
    # Matches every hour at 5 minutes past whole
    minutes: 5

automation 2:
  trigger:
    platform: time_pattern
    # Trigger once per minute during the hour of 3
    hours: '3'
    minutes: '*'

automation 3:
  trigger:
    platform: time_pattern
    # You can also match on interval. This will match every 5 minutes
    minutes: '/5'

Do not prefix numbers with a zero - using '00' instead of ‘0’ for example will result in errors.

Webhook trigger

Webhook triggers are triggered by web requests made to the webhook endpoint: /api/webhook/<webhook_id>. This endpoint does not require authentication besides knowing the webhook id. You can either send encoded form or JSON data, available in the template as either trigger.json or trigger.data. URL query parameters are available in the template as trigger.query.

automation:
  trigger:
    platform: webhook
    webhook_id: some_hook_id

You could test triggering the above automation by sending a POST HTTP request to http://your-home-assistant:8123/api/webhook/some_hook_id. An example with no data sent to a SSL/TLS secured installation and using the command-line curl program is curl -d "" https://your-home-assistant:8123/api/webhook/some_hook_id.

Zone trigger

Zone triggers can trigger when an entity is entering or leaving the zone. For zone automation to work, you need to have setup a device tracker platform that supports reporting GPS coordinates. This includes GPS Logger, the OwnTracks platform and the iCloud platform.

automation:
  trigger:
    platform: zone
    entity_id: device_tracker.paulus
    zone: zone.home
    # Event is either enter or leave
    event: enter  # or "leave"

Geolocation trigger

Geolocation triggers can trigger when an entity is appearing in or disappearing from a zone. Entities that are created by a Geolocation platform support reporting GPS coordinates. Because entities are generated and removed by these platforms automatically, the entity id normally cannot be predicted. Instead, this trigger requires the definition of a source which is directly linked to one of the Geolocation platforms.

automation:
  trigger:
    platform: geo_location
    source: nsw_rural_fire_service_feed
    zone: zone.bushfire_alert_zone
    # Event is either enter or leave
    event: enter  # or "leave"

Multiple triggers

When your want your automation rule to have multiple triggers, just prefix the first line of each trigger with a dash (-) and indent the next lines accordingly. Whenever one of the triggers fires, your rule is executed.

automation:
  trigger:
      # first trigger
    - platform: time_pattern
      minutes: 5
      # our second trigger is the sunset
    - platform: sun
      event: sunset