Comcast is promoting WiFi-based motion detection as a part of its new Xfinity Shield home protection platform, allowing routers and wireless devices to detect people moving through a home without cameras or motion sensors.
This feature was announced as part of a new Xfinity Shield product offering on Tuesday, a new application suite that combines cybersecurity, physical home monitoring, and family safety features through Xfinity WiFi and the Xfinity app.
Part of this new offering is WiFi Shield, which is included at no additional cost for Xfinity Internet customers with compatible gateways. It combines Xfinity’s CyberSecure network protection, Family Settings, and WiFi Motion, with Home Watch, Away Watch, and Dark Watch modes used to control when notifications are generated.
Comcast is also launching Shield Select for $15 per month, which adds an indoor camera, door/window sensor, cloud video storage, and 24/7 urgent response functionality.
However, while Comcast is now making WiFi Motion a major part of its WiFi Shield security offering, the motion detection feature isn’t new.
A Reddit post from August 21, 2024, shows an Xfinity customer receiving an email introducing WiFi Motion.
This email describes the same functionality as today’s announcement, stating that the feature detects disruptions to WiFi signals between the gateway and devices on the network and generates notifications in the Xfinity app.
“It works too. It detects motion to the point of raising your hand to change the channel with the remote control. Detects my cat walking across the living room,” reads another user using the feature in 2024.
WiFi NOW also reported in February that Comcast had offered WiFi Motion “for a long time” and was ramping up its marketing, including advertising it during Olympic hockey broadcasts.
Turning WiFi signals into motion sensors
WiFi Motion works by turning the radio links between an Xfinity Gateway and stationary WiFi devices into virtual motion sensors.
According to support documents, customers select stationary WiFi devices, such as smart speakers or thermostats, positioned around the home. When someone moves through the area between the gateway or extender and one of those devices, their body changes how the WiFi radio signals travel.
Comcast says the system detects these changes in the home’s radio frequency signals and uses them to determine that movement has occurred. Customers will then receive notifications through the Xfinity app without installing a camera or motion detector.
Xfinity says the system does not identify who is moving or determine their exact location, and WiFi Motion is opt-in and disabled by default.
“It is designed to detect motion, not identify specific people, and does not track the exact location of movement. Notifications indicate when movement is detected between a connected device and the Xfinity Gateway,” explains an Xfinity support document.
However, the technology can be sensitive, with Comcast providing different motion sensitivity levels to filter out movement from small pets weighing around 40 pounds or less.
The company warns that the system has no visual information and therefore may not always distinguish a small pet from a similarly sized child.
Source: Xfinity
Comcast also advises customers in apartments and other buildings with shared walls to lower the sensitivity if movement outside the sensing zone causes unwanted detections.
A Comcast patent application provides a glimpse into how this type of system can work.
The pending patent, titled “Methods, systems, and apparatuses for presence detection,” was filed by Comcast Cable Communications in September 2023 and published in April 2025.
It describes using stationary network devices for motion detection and analyzing changes in characteristics such as the wireless signals to determine when an object or person has moved through a space.
The patent explains that WiFi signals can travel along multiple paths as they reflect or scatter off walls, people, and other objects. Movement changes those paths and the resulting wireless signal, allowing software to detect that something in the environment has moved.
Comcast’s patent cites several earlier Cognitive Systems patents related to WiFi motion detection, including technology for detecting motion from repeated wireless transmissions and motion detection in mesh networks.
Using WiFi as an invisible motion sensor raises questions about what happens to the data generated when people move around their houses.
As first spotted by TechCrunch, Comcast’s WiFi Motion documentation says the company may disclose information generated by the feature to third parties “without further notice to you” in connection with a law enforcement investigation or proceeding, a dispute involving Comcast, or pursuant to a court order or subpoena.
Comcast separately states that it does not monitor the motion or notifications generated by WiFi Motion.
The company’s documentation does not explain what WiFi Motion information Comcast retains, how long it keeps it, or what it could provide in response to a legal demand.
BleepingComputer contacted Comcast with questions about the generated data and will update the article if we receive any additional information.
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