> For the complete documentation index, see [llms.txt](https://help.appybuilder.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.appybuilder.com/components/reference/sensors/lightsensor.md).

# LightSensor

LightSensor is a non-visible component that measures the ambient light level (illumination) in lx.

**Event-handler block.** Event is triggered when a sensor change occurred

![](/files/-LGrKQJzE7fBgLWMDkOF)

**Properties block.**

LightSensor includes following properties-blocks. They allow you to determine if user's device has this type of sensor or enable / disable this sensor.

![](/files/-LGrM2ukCBZoWUqmO3Ft) ![](/files/-LGrNTcuQg7HuM3n9tUg)

Example

In Screen initialize , you can check if LightSensor is available or not. You can use block LightSensor.LightChanged to determine the sensitivity of light changed in lx unit:

![](/files/-LGuYPwFlmv1CDkLfIXp)

![](/files/-LGuQZSUuxtyKaQGfsTD)