Comcast is rolling out Wi-Fi motion sensing to its Xfinity gateways, a free opt-in feature that allows its routers to detect movement at home (Jennifer Pattison Tuohy/The Verge)

Comcast is rolling out Wi-Fi motion sensing capabilities to millions of compatible Xfinity gateways, transforming routers into motion detectors. This feature, part of the Xfinity Shield service, detects movement by analyzing signal disruptions between the gateway and connected devices. Comcast's free offering can send activity alerts via the Xfinity app and includes Home, Away, and nighttime monitoring modes, all without the need for additional motion sensors.

The Verge notes that Wi-Fi motion sensing, a technology that has been around for some time, is now accurate and reliable enough to gain traction. While Linksys experimented with a similar service in 2021, it was discontinued a few years later. Another player, Wiz, introduced Wi-Fi-sensing smart bulbs in 2023, and recently, Philips Hue incorporated a comparable radio-frequency sensing technology into its products using Zigbee instead of Wi-Fi.

Comcast's motion sensing integrates seamlessly with new modes within the Xfinity app -- Home Watch, Away Watch, and Dark Watch (a night/sleep mode), enabling users to toggle the sensing on or off according to their activities.