Comcast is turning tens of millions of routers into motion detectors

Comcast is turning tens of millions of its home routers into motion detectors. The feature, called WiFi Motion, uses a home’s own WiFi signal to sense movement, without any cameras. It is part of a new service called Xfinity Shield, which the company began rolling out on 18 August. It set out the details in an announcement.

WiFi Motion works by reading changes in the radio signal between an Xfinity router and a connected device, Comcast said. When something moves and disrupts that signal, the app sends an alert to the customer. The company said it does this without recording video, capturing images or identifying anyone. It casts the tool as awareness, not a full security camera.

The feature is opt-in and free for internet customers with a recent Xfinity gateway, The Verge reported. It pairs with three modes in the app: Home Watch, Away Watch and Dark Watch. Users can turn sensing on or off depending on whether they are in, out or asleep.

What Xfinity Shield includes

WiFi Motion is one piece of a wider bundle. The free tier, WiFi Shield, also folds in Comcast’s network cybersecurity and a set of parental controls. The cybersecurity blocks an average of 30 million threats a day, the company says. Comcast says the average customer now connects 36 devices to home WiFi.

There is a paid tier too. Shield Select costs $15 a month, the company said. It adds an indoor camera, a door and window sensor, cloud video storage and a 24/7 emergency-response option. It described the camera as AI-powered, able to tell apart people, pets, vehicles and package deliveries.

CNET reporter Tyler Lacoma noted that those recognition features are not new. Cameras have sorted people from packages and pets since well before the recent AI boom, he wrote.

How the sensing works

The technology has limits and settings. It needs the gateway plus stationary devices such as thermostats or speakers, not phones, The Register reported. Comcast advises placing equipment so signals cross the areas to be watched, and testing coverage regularly.

Users can tune it. A setting can tell the system to ignore small pets, though Comcast warns this may also miss small children, according to The Register. Sensitivity can be set to low, medium or high. The highest setting suits detached homes, and lower ones suit people who share walls with neighbours.

Comcast stressed the privacy limits. WiFi Motion does not track individuals or their precise movements and cannot identify specific people, it said. The company also said it does not monitor the motion or alerts the service generates. The Register still described the wording as leaving room for interpretation. Comcast does not consider WiFi Motion a home-security service, only a feature, the outlet noted.

The privacy questions

The launch has drawn concern all the same. The Register pointed to Comcast’s own small print. It suggests the service may be less private than the marketing implies, the outlet said.

That fine print covers data sharing. Comcast “may disclose information generated by your WiFi Motion to third parties without further notice to you”, the policy says. That covers a law-enforcement investigation, a dispute involving Comcast, or a court order or subpoena. The company does not spell out what information, or which third parties beyond law enforcement, that might involve, The Register noted.

Others went further. TechRadar’s Alex Blake called the rollout a potential “privacy nightmare”. He argued that millions of people who never bought a router to be tracked will now have one that can. He raised the risk that a future update could switch the feature on by default, and that presence data could become a target for hackers who want to know when a home is empty. Large stores of personal data have drawn breaches before.

The comparison that spread online was blunter. On Reddit, one user called the system “Flock for your bedroom”, likening it to Flock, the licence-plate camera firm that has drawn its own backlash. TechRadar highlighted the post.

Not a new idea

WiFi sensing is not unique to Comcast. The company launched WiFi Motion in 2025, and rivals have tried versions of the idea for years. Linksys offered a similar service in 2021 but later dropped it, and the smart-home firm Plume has run WiFi sensing since 2020, The Register reported.

The wider industry is moving the same way. Lighting makers such as Philips Hue have added sensing to their products, and the home-security company ADT bought Origin Wireless, a pioneer of the technique. A formal WiFi-sensing standard, known as 802.11bf, was ratified in 2025. Chipmakers including Qualcomm and MediaTek are building it into newer WiFi chips, The Register reported.

That trajectory is part of the worry.

CNET’s Lacoma wrote that the goal of presence sensing is the opposite of invasive surveillance, and that it can preserve privacy better than a camera. But the scale is what sets Comcast’s move apart. Turning a feature on across tens of millions of routers reaches far more homes than a gadget someone chooses to buy.

Comcast frames the change as protection, not surveillance. “The network should do more than connect devices,” chief growth officer Jon Gieselman said in a statement. Whether customers see it that way, and how the presence data is handled and shared, will decide how the feature is received.

Comcast did not respond to CNET’s request for comment, and similar privacy questions have trailed the technology before.