Siren turned on

The Siren turned on trigger is useful when you want Home Assistant to react as soon as a siren starts sounding. You can use it to send an alert, turn on lights, or start another automation the moment a siren changes from off to on.

Using this trigger from the user interface

If you prefer building automations visually, Home Assistant walks you through this trigger step by step. You pick what to watch, tweak a few options, and save. No YAML knowledge required.

To use this trigger in an automation:

1. Go to Settings > Automations & scenes.
2. Open an existing automation, or select Create automation > Create new automation.
3. In the When section, select Add trigger.
4. Select what you want to monitor. Under By target (see Targets), pick the area your siren is in. You can also select a floor, a device, a specific entity, or a label.
5. From the triggers shown for that target, select Siren turned on.
6. Under Trigger when (see Behavior), pick Each, First, or All to control how the trigger behaves when multiple sirens are targeted.
7. Under For at least, set how long the siren must stay on before the trigger fires. Leave it at zero to fire right away.
8. Select Save.

Options in the UI

Using this trigger in YAML

If you work directly in YAML, or you want to know exactly what Home Assistant does under the hood, this section has the technical reference. It lists the field names you use in YAML, their types, and which ones are required.

In YAML, refer to this trigger as siren.turned_on. A basic example looks like this:

trigger: siren.turned_on
target:
  entity_id: siren.entry

This fires every time siren.entry turns on.

Options in YAML

YAML sometimes provides additional options for more complex use cases that are not available through the UI.

Targets of the trigger

This trigger requires a target. The target is the object that Home Assistant will watch. You can select a single entityAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more], a device, an area, a floor, or a label as a target, and Home Assistant will watch every matching siren entity behind that target.

• Entity: one specific siren entity, such as siren.living_room.
• Device: every siren entity that belongs to a device.
• Area: every siren entity in a room or area.
• Floor: every siren entity on a floor.
• Label: every siren entity that shares a label.

You can also select different target types in one trigger. For example, you can add a specific entity and an area as targets in the same trigger to monitor both of them at once.

Behavior with multiple targets

When you target more than one entity (or select an area, floor, or label that contains several), the Trigger when option controls how the trigger responds:

• Each (any in YAML, default): the trigger fires every time any one of the targeted entities transitions. For example, if you monitor three motion sensors in the living room and someone walks past sensor 1, the automation fires. When they walk past sensor 2 a moment later, it fires again. Every individual event counts.
• First (first in YAML): the trigger fires only on the first transition in the targeted group, then waits until all targeted entities have reset before it fires again. For example, if you monitor the same three motion sensors, the automation fires when the first one picks up movement (someone entered the room). The other two firing afterward are ignored, so you get one notification per “someone walked in” event instead of three.
• All (last in YAML): the trigger fires only after the last targeted entity in the group has fired, meaning all of them are now in the expected state. For example, if you monitor the lights in the living room, bedroom, and hallway, the automation fires only once all three have turned off. This is useful for scenarios like “start the robot vacuum only after every light on the floor is off,” so you know the room is truly empty.

Good to know

• The trigger only fires when a siren changes from a known off state to on.
• If a siren returns from unavailable or unknown, that recovery does not fire the trigger.
• To react when a siren stops, use Siren turned off.

Try it yourself

Ready to test this? Go to Settings > Automations & scenes, create a new automation, and add this trigger. Save the automation, then change the state of the targeted entity to watch the trigger fire on your actual entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more].

More examples

Real scenarios where this trigger fires in automations and scripts. Copy any example and adapt it to your setup.

Automation: send a phone alert when the siren starts

If a siren turns on while you are outside or in another room, a phone alert helps you notice it right away. This automation sends a notification as soon as the entry siren starts.

• Trigger: Siren turned on
  • Target: Entry siren
• Action: Send a notification message
  • Target: My Device (notify.my_device)

alias: "Notify when the siren turns on"
triggers:
  - trigger: siren.turned_on
    target:
      entity_id: siren.entry
actions:
  - action: notify.send_message
    target:
      entity_id: notify.my_device
    data:
      title: "Siren started"
      message: >
        The entry siren just turned on.

Automation: turn on the porch lights when the siren starts

At night, a siren can be easier to deal with if the area around your home is lit. This automation turns on the porch lights when the outdoor siren starts, making it easier to check what is happening.

• Trigger: Siren turned on
  • Target: Outdoor siren
  • For at least: 00:00:05
• Action: Turn on light

alias: "Turn on porch lights when the siren starts"
triggers:
  - trigger: siren.turned_on
    target:
      entity_id: siren.outdoor
    options:
      for: "00:00:05"
actions:
  - action: light.turn_on
    target:
      area_id: porch

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with the trigger you’re using and what you expected to happen, or share on our subreddit /r/homeassistant.

Related triggers

These triggers work well alongside this one:

• Siren turned off: Triggers after one or more sirens turn off.