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Comcast announced a home protection platform called Xfinity Shield on Tuesday, August 18, built around a feature that turns a customer's router into a motion sensor. The feature, WiFi Motion, detects people moving through a house without any camera or dedicated sensor, BleepingComputer reported.
The technology works by treating the radio links between an Xfinity gateway and stationary devices, such as a smart speaker or a thermostat, as invisible tripwires. A person walking between the two changes how the WiFi signal travels. Comcast's software reads those changes and pushes a notification to the Xfinity app. It supports XB7 gateways and newer, and it covers millions of installed devices.
Comcast says the system does not identify who is moving or pinpoint where in the house they are. It is opt in and switched off by default. Sensitivity is adjustable, partly so households can filter out pets weighing roughly 40 pounds or less, though the company warns that with no visual information the system may not always tell a small pet from a similarly sized child. Customers in apartments and other buildings with shared walls are advised to lower sensitivity if movement next door keeps triggering alerts.
The privacy terms attached to the feature drew attention first. As TechCrunch reported, an Xfinity support page states that Comcast "may disclose information generated by your WiFi Motion to third parties without further notice to you" in connection with a law enforcement investigation or proceeding, any dispute involving Comcast, or under a court order or subpoena.
Comcast says separately that it does not monitor the motion data or the notifications the feature produces. Its documentation does not say what WiFi Motion information the company retains, how long it holds it, or what it would hand over in response to a legal demand.
The underlying capability is not new. An Xfinity customer posted a company email describing the same functionality in August 2024, and one user at the time reported that it picked up a hand raised to change the television channel and a cat crossing the living room. A Comcast patent application filed in September 2023 and published in April 2025 describes using stationary network devices to detect presence by analyzing changes in wireless signal characteristics.
WiFi Shield comes at no extra cost to Xfinity Internet customers with a compatible gateway, bundling the motion feature with Comcast's CyberSecure network protection and its Family Settings controls, plus Home Watch, Away Watch and Dark Watch modes that govern when alerts fire. A paid tier, Shield Select, costs $15 a month and adds an indoor camera, a door and window sensor, cloud video storage and a 24/7 urgent response service.
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