Wireless signals can carry information—and reveal information about their surroundings. At very different powers and in purpose-built systems, electromagnetic energy can also disrupt electronics or damage a target.
Sources checked September 23, 2026 · Selected examples, not an inventory of every system
Imagine noticing someone moved because a shadow changed. Wi-Fi sensing uses a different clue: changes in a received radio signal.
Software interprets those changes. Detecting motion, counting people and estimating body positions are separate capabilities. Each needs its own setup and evidence.
Sharing a part of the spectrum does not make two exposures equivalent. Power, frequency, beam shape, duration and distance matter. A Wi-Fi sensing demonstration does not establish harm from ordinary wireless exposure.
Signals reach a receiver along multiple paths. Walls, objects and moving bodies affect those paths. Sensing software looks for patterns in the resulting measurements.
A relatively steady scene can produce steadier measurements.
A transmitter sends a signal through the environment.
Movement changes reflections and other signal properties.
Systems may use signal strength or a more detailed record of how the signal changes along its path. Researchers call that channel state information, or CSI.
An algorithm estimates motion or another trained outcome.
WiFi Motion is opt-in. Compatible gateways and connected devices detect movement through signal changes and can provide activity notifications. Xfinity says it captures no images, video or audio, and Comcast does not monitor the generated motion or notifications.
The documentation reviewed here does not establish that Comcast creates detailed interior maps, identifies occupants or runs the research systems below in subscribers’ homes.
Placement, building materials and signal coverage affect detection. Comcast also describes potential disclosure of generated information through lawful legal process.
Xfinity: feature, activation, limitations and privacy terms ↗
Motion detection, counting people, identifying someone and reconstructing a room are different tasks. Evidence for one does not prove the others are happening in a particular product.
The capabilities are real research topics. The setup and limits belong beside every result.
UCSB researchers estimated the number of people walking behind walls using a Wi-Fi transmitter and receiver outside the area. They reported 44 experiments in five campus spaces, with up to 20 people.
Depatla & Mostofi · 2017 paper ↗A configured experiment involving walking people. It does not establish universal detection of still occupants or reveal their identities.
DensePose From WiFi used trained software to estimate positions and body surfaces from Wi-Fi measurements, using a specific arrangement of transmitters and receivers.
Geng, Huang & De la Torre · 2023 preprint ↗Images were used to teach the software during training. It performed worse in a room layout it had not seen before. An inferred body representation is not a photograph, and this paper is not proof of Comcast deployment.
NIST and FDA collaborators used Wi-Fi measurements and the BreatheSmart algorithm to classify simulated breathing patterns.
Mosleh et al. · 2022 study ↗The demonstration used a mannequin that simulated breathing in a controlled chamber, plus specially modified router software. It was not a clinical diagnosis service operating in ordinary homes.
UCSB demonstrated 3D imaging of static structures behind walls using Wi-Fi measurements collected by two moving drones.
Karanam & Mostofi · 2017 project and paper ↗The positions and movement of the drones, along with reconstruction software, were part of the experiment. This does not demonstrate that any stationary household router can produce a complete floor plan.
Directed-energy weapons are designed to deliver concentrated energy to a target. Their demonstrated effects do not transfer automatically to everyday communications equipment.
This is the system often described as a “heat ray.” It creates a heating sensation in the skin intended to make a person move away. The mechanism is electromagnetic heating, not sound; “cooking people” is not a precise description of its intended effect.
“Non-lethal” describes its intended role, not a guarantee of no injury. GAO identifies unresolved health and ethical questions around directed-energy weapons.
GAO: mechanisms, effects and limitations ↗The U.S. Air Force Research Laboratory reported a 2023 demonstration of THOR against a drone swarm. This is a purpose-built counter-drone system aimed at electronics.
A reported test demonstrates a capability under those conditions; it does not establish unlimited range or reliable performance in every operational setting.
AFRL: April 2023 demonstration ↗In November 2025, the UK Ministry of Defence reported drone shoot-down trials and a contract for Royal Navy delivery from 2027. That announcement describes a tested system and a future delivery plan.
Laser performance depends on conditions including the atmosphere, tracking and maintaining the beam on the target. A test or procurement announcement is distinct from an operational deployment.
UK MOD: trial and delivery announcement ↗ · GAO: technical limitations ↗Lasers in space are real. NASA uses optical communications technology to send data between spacecraft and receivers. That is a communications application.
To establish that an orbiting laser is a weapon, we would need evidence identifying the system, what it is designed to do and what it has demonstrated. The sources on this page do not establish operational orbital laser weapons.
Keep a proposed system, a laboratory test, a space communications link and a deployed weapon in separate categories.
NASA: optical communications ↗Space Force reported accepting Meadowlands for operational use on June 8, 2026. It describes ground-based radio-frequency equipment that disrupts satellite communications. This is electronic warfare; the announcement does not describe an orbital laser.
Space Force · June 2026 announcement ↗A U.S. Space Force threat assessment says China has ground-based laser weapons capable of interfering with or damaging satellite sensors. This is an attributed government assessment, rather than an independently reproduced test presented here.
A laser directed from Earth toward a satellite is a different configuration from an orbiting weapon aimed at the ground.
Space Force · Space Threat Fact Sheet ↗Who can enable sensing? Do household members and visitors know it is active?
Are raw measurements, motion events or inferred patterns retained? What leaves the device?
Who can view, share or request the information? What retention and deletion rules apply?
Does a setting disable sensing itself, or only silence notifications? How is that verified?
These are technology and privacy questions. They do not establish that a provider is secretly mapping homes, that a person is being targeted, or that a sensing result demonstrates a health effect.
For an EMF research comment, ask which frequencies, operating modes, exposure levels and durations a study actually covers. The existence of a weapon is not a substitute for exposure-specific health evidence.