Light is detected

The Light is detected condition passes when one or more light binary sensors are currently detecting light. Use it to gate an automation on a lit area, like only running a routine while a closet light is still on, or only sending a reminder if a room is currently bright.

Using this condition from the user interface

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

To use this condition in an automation:

1. Go to Settings > Automations & scenes.
2. Open an existing automation, or select Create automation > Create new automation.
3. In the And if section, select Add condition.
4. From the search box, search for and select Light is detected.
5. Under Targets (see Targets), select one or more light sensors, devices, an area, a floor, or a label.
6. If you selected more than one target, under Condition passes if, pick Any or All.
7. Under For at least, you can set how long the sensors must keep detecting light before the condition passes. Leave it at zero for the condition to pass as soon as light is detected.
8. Select Save.

Options in the UI

Using this condition 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 condition as illuminance.is_detected. A basic example looks like this:

condition: illuminance.is_detected
target:
  entity_id: binary_sensor.closet_light_sensor

This passes when the closet light sensor is currently detecting light.

Options in YAML

Targets of the condition

This condition requires a target. The target is the object that Home Assistant will check. You can point the condition at 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, and Home Assistant will evaluate every matching illuminance entity behind that target.

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

You can also select different target types in one condition. For example, you can add a specific entity and an area as targets in the same condition to check 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 Condition passes if option controls how the results combine:

• Any (default): the condition passes if at least one of the targeted entities matches. For example, if you check three smoke sensors and only one of them detects smoke, the condition still passes. This is useful for questions like “is there smoke anywhere in the house?”
• All: the condition passes only when every targeted entity matches. For example, if you check the same three smoke sensors, the condition passes only once all three report cleared. This is useful for “is the entire house safe now?” checks, so your automation does not send an all-clear while one room still has a reading.

Good to know

• This condition works with binary sensors that have the light device class. The sensor’s threshold for what counts as “light detected” is set on the device itself.
• Sensors that are unavailable or unknown are skipped for Any and fail for All.
• For numeric illuminance readings (in lux), use Illuminance instead.
• To check the opposite state, use Light is not detected.

Try it yourself

Ready to test this? Go to Settings > Automations & scenes, open an automation, and add this condition. Trigger the automation with and without the condition met, and watch whether it continues or stops.

More examples

Real scenarios where this condition gates an automation. Copy any example and adapt it to your setup.

Automation: only send a closet reminder if the light is on

When the daily 23:00 evening check runs, send a notification only if the closet light sensor has been detecting light for at least 10 minutes, so a brief visit doesn’t trigger an alert.

• Trigger: Time: 23:00
• Condition: Light is detected
  • Target: Closet light sensor
  • For at least: 00:10:00
• Action: Send a notification message
  • Target: My Device (notify.my_device)

alias: "Remind to turn off closet light"
triggers:
  - trigger: time
    at: "23:00:00"
conditions:
  - condition: illuminance.is_detected
    target:
      entity_id: binary_sensor.closet_light_sensor
    options:
      for: "00:10:00"
actions:
  - action: notify.send_message
    target:
      entity_id: notify.my_device
    data:
      message: "The closet light has been on for over 10 minutes."

Still stuck?

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

Related conditions

These conditions work well alongside this one:

• Light is not detected: Tests if light is currently not detected.

• Illuminance: Tests if an illuminance value is above a threshold, below a threshold, or in a range of values.