Timer started

The Timer started trigger fires when a timer begins from the idle state. Use it when you want something to happen as soon as a countdown starts.

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 timer you want to watch. You can also select an area, a floor, a device, or a label.
5. From the triggers shown for that target, select Timer started.
6. Under Trigger when (see Behavior), pick Each, First, or All.
7. Under For at least, set how long the timer must stay started before the trigger fires. Leave the default 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 timer.started. A basic example looks like this:

trigger: timer.started
target:
  entity_id: timer.entryway

This fires when timer.entryway starts.

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 timer entity behind that target.

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

• This trigger is for timers that start from idle.
• If you resume a paused timer, use Timer restarted instead.
• The For at least option here adds extra delay after the timer starts. It is separate from the timer’s own countdown.

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: turn on the porch light when the entry timer starts

Start a short entry timer when someone arrives home, and switch on the porch light at the same time.

• Trigger: Timer started
  • Target: Entryway timer
  • Trigger when: Each
• Action: Turn on light

alias: "Turn on the porch light when the entry timer starts"
triggers:
  - trigger: timer.started
    target:
      entity_id: timer.entryway
actions:
  - action: light.turn_on
    target:
      entity_id: light.porch

Automation: announce when the laundry timer starts

Send a message when someone starts the laundry timer so everyone knows the cycle has begun.

• Trigger: Timer started
  • Target: Laundry timer
  • Trigger when: Each
• Action: Send a notification message
  • Target: My Device (notify.my_device)

alias: "Notify when the laundry timer starts"
triggers:
  - trigger: timer.started
    target:
      entity_id: timer.laundry
actions:
  - action: notify.send_message
    target:
      entity_id: notify.my_device
    data:
      message: "The laundry timer has started."

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:

• Timer restarted: Triggers when one or more timers are restarted.

• Timer finished: Triggers when one or more timers finish.