First look: Comcast has begun rolling out WiFi Motion, a feature that allows compatible Xfinity routers to detect movement inside a home without the need for cameras or separate motion sensors. The move gives Comcast a way to add a basic layer of home monitoring through software while illustrating how broadband equipment could play a larger role in connected-home security.

The feature is available through an update to the Xfinity Internet app and works with XB7 gateways and newer models. It is part of the company's new Xfinity Shield service and comes at no additional cost.

WiFi Motion detects changes in the wireless signals traveling between an Xfinity gateway and connected devices. When someone moves through the home, those changes can indicate activity. Customers can choose to receive notifications through the app.

The system can be set to Home Watch, Away Watch, or Dark Watch, the latter of which is intended for overnight use. Customers can also turn the feature on or off through the app.

Comcast says it has spent several years improving the system's accuracy. Early versions of Wi-Fi sensing often struggled to distinguish actual movement from normal fluctuations in a home's wireless environment.

"We have spent the last three years advancing the algorithms for WiFi Motion and tightening up some of the irregularities that came with the early versions of Wi-Fi sensing," Kohposh Kuda, SVP of consumer products at Xfinity, told The Verge.

"We're at a point where we feel confident in the WiFi Motion capability that customers can use this for motion detection in their home and for a basic level of security."

The technology is not intended to replace a conventional security system. It can detect movement, but it cannot provide video footage or identify exactly who is in a room. Comcast continues to sell cameras and physical sensors through Xfinity Shield Select, a $15-per-month package that includes an indoor camera, a door and window sensor, cloud video storage, and a 24/7 urgent-response service.

"But for the average household ... this provides an adequate level of security protection," Kuda says.

The appeal is largely practical. WiFi Motion uses equipment already in a customer's home, so there is no new device to buy, install, or charge. For Comcast, that makes Wi-Fi sensing a software feature that can be distributed across millions of existing gateways.

Other companies have pursued similar ideas. Linksys introduced a Wi-Fi sensing service in 2021 but later discontinued it. Wiz added Wi-Fi sensing capabilities to its smart bulbs in 2023. Philips Hue has also introduced motion-aware technology that uses Zigbee radio signals.

Comcast sees WiFi Motion as a starting point rather than a finished product category. The company says the same type of sensing could eventually support applications beyond basic home monitoring, including services designed to help people age in place.

"We believe this is the foundation for what we think we can do with more advanced use cases," Kuda says.