Switch turned on

The Switch turned on trigger is useful when you want something else to happen as soon as a switch is activated. Use it to start a related device, send a reminder, or begin a timed routine after a switch has been on for a while.

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 switch you want to monitor. You can also select an area, a floor, a device, or a label.
5. From the triggers shown for that target, select Switch turned on.
6. Under Trigger when (see Behavior), pick Each, First, or All.
7. Under For at least, set how long the switch must stay on before the trigger fires.
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. For how an automation is built in YAML, refer to Automations in YAML.

In YAML, put the settings that are specific to this trigger under options. Keep target, if the trigger uses one, and general settings such as id, alias, enabled, and variables at the top level, next to trigger.

When this trigger starts an automation, it passes data about what happened to the automation. You can use this trigger data in the templates of your conditions and actions. To see which data is available, refer to Trigger data in templates.

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

trigger: switch.turned_on
target:
  entity_id: switch.coffee_machine

This fires whenever switch.coffee_machine turns on.

Options in YAML

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 switch or toggle helper behind that target.

• Entity: one specific switch or toggle helper, such as switch.coffee_maker.
• Device: every switch or toggle helper that belongs to a device.
• Area: every switch or toggle helper in a room or area.
• Floor: every switch or toggle helper on a floor.
• Label: every switch or toggle helper 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.

To learn which entities Home Assistant includes for a device, area, floor, or label, and how it handles several entities, refer to Automation targets.

Trigger variables

When the trigger reacts, the trigger variable identifies the entity that made it react. This is useful when a target contains multiple entities, such as a device, area, floor, or label.

The following trigger-specific variables are available:

• trigger.entity_id: Entity ID of the entity that made the trigger react.
• trigger.from_state: Previous state object of that entity.
• trigger.to_state: New state object of that entity.
• trigger.for: Timedelta object of how long the trigger criteria were met, if applicable.

For example, use {{ trigger.to_state.name }} in an action to include the name of the entity that made the trigger react in a notification.

The trigger variable describes the entity that made the trigger react. It doesn’t contain all the entities of the target.

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 (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: the trigger fires only on the first transition in the targeted group, then waits until none of the targeted entities is in that state anymore 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: 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

• You can use switch entities and toggle helpers (input_boolean) as targets.
• A switch in the unknown or unavailable state does not count as turned on.
• If the switch turns off before the For at least time finishes, the timer resets.
• To react when a switch stops instead, use Switch 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, and then make the trigger react. For example, change the state of the targeted 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], turn on a light that the trigger monitors, or change its brightness. To check whether the automation ran, open its traces.

More examples

Real scenarios where this trigger fires in automations and scripts. Copy any example and adapt it to your setup. In the visual editor, select the UI options listed in the example when they are available, or paste the YAML code.

Automation: cut power to the iron after it has been on too long

If your iron is plugged into a smart power plug and stays on for more than 15 minutes, this automation cuts the power so it doesn’t keep heating unattended.

• Trigger: Switch turned on
  • Target: Iron power plug
  • Trigger when: Each
  • For at least: 00:15:00
• Action: Turn off switch
  • Target: Iron power plug

alias: "Cut power to iron after 15 minutes"
triggers:
  - trigger: switch.turned_on
    target:
      entity_id: switch.iron_power_plug
    options:
      for: "00:15:00"
actions:
  - action: switch.turn_off
    target:
      entity_id: switch.iron_power_plug

Automation: start the bathroom fan when the shower light turns on

When the shower light goes on, start the bathroom exhaust fan to reduce moisture buildup.

• Trigger: Switch turned on
  • Target: Shower light switch
• Action: Turn on fan
  • Target: Bathroom fan

alias: "Bathroom fan with shower light"
triggers:
  - trigger: switch.turned_on
    target:
      entity_id: switch.shower_light
actions:
  - action: fan.turn_on
    target:
      entity_id: fan.bathroom

Still stuck?

To find out why the trigger didn’t react, make the change that it should react to, and then open the traces of the automation. If the automation didn’t run, there’s usually no trace, but some triggers record a Did not trigger trace. For details, refer to Testing automations. For common problems and their solutions, refer to Troubleshooting automations.

If that doesn’t help, 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

Explore related triggers:

• Switch turned off: Triggers when one or more switches turn off.