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url: /sensors/virtual.md
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# Virtual sensors

A **virtual sensor** is a sensor with no plugin behind it. You create it yourself, camera.ui holds its state, and you set that state from the UI or from an [automation](/automations/).

Typical uses: a doorbell you trigger from an automation, a contact you flip when an MQTT message arrives, a switch for something no plugin reports. Otherwise it behaves like any other [sensor](/sensors/): assign it to cameras, place it on the video as a [shortcut](/cameras/shortcuts), export it to your smart home, use it as an automation trigger.

Creating, renaming, and deleting virtual sensors needs admin.

## Create a virtual sensor

**Create virtual sensor** on the **Sensors** page asks for:

* **Type.** What the sensor represents. Can't be changed later.
* **Name.** How the sensor appears in camera.ui, for example "Front Door". Two virtual sensors of the same type can't share a name.

The sensor starts in its idle state: off, closed, locked, or disarmed, depending on the type. It belongs to no camera until you assign cameras from its row; it then shows up in their Overview.\[^cameradelete]

## Available types

There are 23 types:

* **Doorbell.** A ring you trigger. It resets itself two seconds later.
* **Switch.** On or off.
* **Contact.** Open or closed, for a door or window.
* **Occupancy.** Occupied or empty.
* **Smoke.** Clear or triggered.
* **Leak.** Clear or triggered.
* **Light.** On or off, with brightness.
* **Siren.** On or off, with volume.
* **Lock.** Locked or unlocked.
* **Garage.** Open or closed.
* **Security System.** Off, Home, Away, or Night.
* **Temperature.** A temperature reading.
* **Humidity.** A humidity reading.
* **Gas.** Clear or triggered.
* **Carbon Monoxide.** Clear or triggered.
* **Heat.** Clear or triggered.
* **Cold.** Clear or triggered.
* **Vibration.** Clear or triggered.
* **Tamper.** Clear or triggered.
* **Problem.** Clear or triggered.
* **Power.** Clear or triggered.
* **Illuminance.** A light-level reading in lux.
* **CO₂.** A carbon dioxide reading in ppm.

## Control it

Doorbell, Switch, Light, Siren, Lock, Garage and Security System get the same controls as plugin-provided ones (see [Controls & states](/sensors/controls)): on an assigned camera's **Overview** tab, and in the sensor's edit dialog on the **Sensors** page, which also covers sensors assigned to no camera.

Contact, Occupancy, Smoke, Leak, Temperature, Humidity, Gas, Carbon Monoxide, Heat, Cold, Vibration, Tamper, Problem, Power, Illuminance, and CO₂ are read-only. Their value comes from an automation.

Lock, Garage and Security System switch immediately, with no "locking" or "opening" state in between.

The last state survives a restart.

## Control it from an automation

In the [automation editor](/automations/), a **Control sensor** action sets a virtual sensor, and a **Sensor change** trigger reacts when its state changes. For the read-only types this is the only way to set a value: an automation that receives an MQTT message, for example, can put that value on a virtual temperature sensor.

## Rename or delete

On the **Sensors** page: click the row to rename, use the row's delete button to remove.\[^delete]

A new name applies everywhere (Overview, shortcuts, automations), and automations using the sensor keep working.

\[^cameradelete]: Deleting a camera only removes the assignment. The sensor itself stays and can be assigned to other cameras.

\[^delete]: Deleting a virtual sensor stops any automation that references it. Creating a new sensor with the same type and name does not restore the link, since it is a new sensor. Point the automation at it again.