Comcast has folded its Wi-Fi-based intruder detection feature into Xfinity Shield, a repackaged bundle of physical and cybersecurity offerings.
The US telco launched WiFi Motion in 2025. Xfinity Shield also includes cybersecurity protections built into the Xfinity Gateway router.
The Wi-Fi sensing technology harnesses the radio waves beamed around a user's home to detect motion and potential intruders.
"Using Xfinity Gateway intelligence, WiFi Motion detects changes in the home's radio frequency signal between the Xfinity Gateway and a Wi-Fi connected device, then sends instant notifications to customers through the Xfinity app when unexpected activity is detected," Comcast said.
"It provides an added layer of awareness without recording video, capturing images or identifying individuals."
The company does not consider this a home security service, merely a feature, because it is not managed by a dedicated security provider.
Not every connected device can support the sensing feature. It uses the Xfinity Gateway, Xfinity Wi-Fi extenders, and up to three other compatible devices around the home.
Crucially, these devices must be stationary. Think thermostats and home speakers, not smartphones or toothbrushes.
Comcast advises users to position the router and extenders so that their signals pass through the areas where they want to detect motion. Open spaces such as hallways work best, and the company urges routine testing to ensure coverage is maintained.
A setting in the Xfinity app allows WiFi Motion to ignore small pets. Animals weighing around 18 kg (40 pounds) or less will not trigger alerts when this setting is enabled, and the app warns this may also exclude small children.
Customers can also adjust the sensitivity of the motion detection, choosing from low, medium, and high-sensitivity modes. Comcast says the latter works best in single-family, detached homes, whereas those who share walls with neighbors may want to choose the less-sensitive settings to avoid meaningless notifications.
The telco also assured customers that WiFi Motion does not track individuals or their precise movements, and cannot identify specific people. It added that it "does not monitor motion and/or notifications generated by the service."
The small print, which also accompanied the 2025 launch, suggests the service may not be quite as private as the marketing implies.
MORE CONTEXT
Comcast states: "Subject to applicable law, Comcast may disclose information generated by your WiFi Motion to third parties without further notice to you in connection with any law enforcement investigation or proceeding, any dispute to which Comcast is a party, or pursuant to a court order or subpoena."
Comcast does not specify what information may be disclosed or which "third parties," beyond law enforcement, might receive it.
How it works
Users can establish "sensing areas" by placing Wi-Fi devices around parts of the home with regular foot traffic.
Comcast describes each sensing area as a long oval extending between two connected devices.
Comcast diagram depicting how Wi-Fi sensing areas are established within the home
Sensing areas can be established through walls separating rooms, although in two-storey or multi-storey homes, the telco encourages customers to avoid placing Wi-Fi equipment directly above or below each other.
Comcast diagram depicting how Wi-Fi sensing areas are established within the home, also showing how top-and-bottom deployments don't work
"Motion is detected within the sensing area when movement disrupts the wireless signals that travel between your Xfinity WiFi equipment and selected WiFi-connected devices within the sensing area," said Comcast.
"Notifications will be sent only when motion disrupts the wireless signals in the sensing area between the WiFi equipment and your connected devices."
Not a novel feature
Comcast is the latest, but not the first, to harness Wi-Fi radio waves for motion detection.
Companies such as Cognitive Systems and Origin Wireless have been developing other uses for wireless signals.
Beyond domestic intruder alerts, the technology can measure occupancy and foot traffic in commercial buildings, helping operators reduce energy consumption and make better use of leased space.
Wireless signals can also be used to support caregivers in places like assisted living centers. Wi-Fi transmissions can help track activity patterns and build a greater understanding of patients' fall risks, for example.
Boffins began working on an official Wi-Fi sensing standard in 2020. Following a draft published by the IEEE in 2023, the 802.11bf standard was ratified in 2025.
Major chipmakers including MediaTek, Qualcomm, and others are now working on embedding the standard into their Wi-Fi 7 chips and beyond.
SaaS biz Plume, which provides smart home services to consumers and ISPs, has offered Wi-Fi sensing since 2020, around the time the 802.11bf working group began devising the standard. ®
