At a major Amazon event in September, the company mentioned that its fourth-generation Echo and Echo Dot devices will include ultrasonic capabilities. This is a feature designed to detect if someone is in the room at any given moment.

The idea is that the Echo will be able to detect if someone is around and, as a result, turn connected devices on or off. This feature is coming this week.

Echo devices will be able to use "inaudible ultrasound" to detect the presence of people in a room. This is like sonar and its purpose is similar to the motion sensing feature of the Echo Show.

This feature can be enabled or disabled in the settings menu of each supported device in the Alexa app. This feature can be turned on or off in the settings menu of each supported device in the Alexa app. Similarly, a new occupancy routine can be set up to actually use this feature.

For example, you can turn lights on and off as you move around the house, or have Alexa play music when someone is in range. This is not particularly outlandish, especially since Alexa already routinely supports a variety of third-party motion sensors. Ultrasound simply eliminates the middleman by letting Echo do all the hard work.

Amazon is not the only company doing this. Google uses ultrasound in its Nest device, which can sense how close a person is. When a person approaches, the Nest mini speaker will highlight the volume controls.

However, Google Assistant cannot use ultrasonic detection to trigger Google Home routines.

This feature will be coming this week, so keep an eye on the Alexa app and play around with the various new routines. If you're not sure how, check out our guide on how to create an Alexa smart home routine. Also, check out the best Alexa skills to get the most out of your virtual assistant.