The fourth-generation Amazon Echo and Amazon Echo Dot are getting an exciting addition to the smart home. These Alexa-enabled speakers can now detect the movement of people to automatically perform some tasks, such as turning lights on or off. Functions that, until now, could only be performed by third-party motion sensors.

The feature, available starting this week through an update to the Alexa app, is already present on smart devices with a camera, like the Echo Show. These, unlike the Amazon Echo and Echo Dot, use the sensor to check for movement in the room. Screenless speakers, on the other hand, make use of an “inaudible ultrasound wave.”

That is, the loudspeaker creates a kind of map of the area by emitting a frequency that is unpredictable to the human ear. It bounces off objects in the room and back, through the microphone, to the Amazon Echo. When a person enters said space, the loudspeaker is capable of detecting the variation and acting accordingly.

These are the uses of the new Amazon Echo motion sensor

Now, what can the motion sensor integrated into an Amazon Echo be used for? Mainly, to activate or deactivate smart devices automatically. In fact, the motion detection function can be configured from the app and we can ask it, for example, to turn on the lights in the living room every time it detects the entrance of a person.

Also, turn off the Fire TV when someone leaves the room or play music if it detects people nearby. Until now, these actions could only be carried out using third-party motion sensors.The feature, though, appears to be limited to turning devices and music on and off. It is not possible, for example, to adjust the lighting intensity based on the natural lighting in that room. It is also not possible to activate a specific mode depending on the time of day.