The appeal is that nothing in the house has to change. No box on the bedroom wall, no pendant to argue about, nothing your mother has to agree to wear. The router is already there, and the software claims to read the home from it.
What it reads is interference. A moving body distorts the radio between the router and everything connected to it, and the software infers movement from that distortion. That is why the coverage is the whole home rather than one room, and it is why the answer comes back coarse.
Key facts
- Wi-Fi sensing works from channel state information (CSI): the distortion a body creates in the signal path. One of Verizon's Fios routers in the United States ships with Origin Wireless "human presence detection" (How Wi-Fi sensing became usable tech, MIT Technology Review, 2024).
- As of February 2024, MIT Technology Review reported that "we have yet to see a commercially viable Wi-Fi device for tracking breathing or detecting falls". Sam Yang of the sensor company Xandar Kardian told the magazine "the signal is just not clean enough", and that in a home "Grandma falling looks a lot like a child jumping off the couch" (MIT Technology Review, 2024).
- The published home trials are small. A 2025 volunteer trial recruited 12 people aged 60 and over; breathing-rate accuracy in homes was 89.25%, against up to 96.90% previously reported in controlled laboratory conditions, and heart-rate error averaged 9.26 bpm. The authors call the study underpowered (IEEE Journal of Translational Engineering in Health and Medicine, via PMC, 2025).
Listings
Nothing published in this section yet.
What the router can actually tell you
A Wi-Fi sensing system is usually software running on a router, a mesh node or a plug-in access point. It watches how the signal between the router and everything connected to it fluctuates, and infers movement from those fluctuations. Because Wi-Fi radio already fills the house, coverage is whole-home rather than room-by-room, and nothing has to be mounted, worn or plugged in beside the bed.
Typical outputs are motion or no-motion for the home, sometimes a coarse zone, and sometimes a "nobody has moved since" timer. Some products layer on activity summaries for a family member's phone.
When it is a reasonable first step
Wi-Fi sensing suits a low-stakes question asked from a distance: has there been any activity in the house today? It is a cheap first step for an adult child who is not ready to install sensors, and it is unobtrusive, because there is no new box in the bedroom. It is a poor fit where the worry is specific — a bathroom, a bed, a long stillness in one chair — because that is exactly the resolution it does not have.
When the worry is that specific, the alternatives are per-room rather than per-home. Radar presence sensors cover one room each with no camera and nothing worn; bed alarms cover one bed and one event; acoustic monitoring covers one room but needs a microphone in it; indoor cameras show the most and are refused in the most rooms. Each costs more effort or more privacy than leaving the router to it, and each answers a question Wi-Fi sensing cannot.
What to ask before buying
- Does it report rooms or only the whole home? Ask for the vendor's own words.
- Does it need specific router hardware, and what happens when the internet provider swaps the router?
- Where is the data processed and stored, and in which country?
- What exactly triggers an alert, and how long can a person be still before anyone is told?
- Does the vendor claim fall detection or vital signs? If so, ask for the study and the medical-device licence.
- Is it sold and supported in Canada?
The nine things to get in writing
Wi-Fi sensing is sold mostly by internet providers and mesh-router brands, whose product pages are written for a general audience rather than a care decision. Before you rely on one, get these in writing from the vendor's own pages: what the sensor actually is; whether there is a camera; whether there is a microphone; whether anything must be worn; the fall-detection claim in the vendor's exact words, if any; where the data is hosted; whether it is sold and supported in Canada; what it costs and on what terms; and a link to the page each answer came from. That is the same set this directory records for every listing, and where a vendor is silent we publish "Not publicly stated" rather than a guess. See the methodology, the sensor-by-sensor comparison in PIR vs mmWave radar vs Wi-Fi sensing vs acoustic, and the attribute table in the directory comparison.
What it cannot do
It cannot reliably tell you which room a person is in, whether they are sitting or lying down, or that a fall happened. It does not distinguish a person from a dog, and every extra body in the home degrades the picture. Signals leak through walls, so a neighbour's movement or a passing visitor can register. Change the router, add a mesh node or move furniture and the system usually has to relearn the space.
Vital-sign features deserve particular care. Where they exist at all, the evidence is small-sample and worse at home than in a laboratory, per the 2025 trial above. Health Canada decides whether software is a medical device from its intended use, judged from "the manufacturer's labelling, including instructions for use manuals, websites, promotional material" (Software as a Medical Device guidance, Health Canada, 2019). If a Wi-Fi product's website promises breathing monitoring or fall detection, ask whether it is licensed as one.
Frequently asked questions
Can Wi-Fi detect a fall?
As of February 2024, MIT Technology Review reported that no commercially viable Wi-Fi device for tracking breathing or detecting falls had yet been seen (MIT Technology Review, 2024). Treat any such claim as unproven until the vendor shows real-world data.
Does Wi-Fi sensing need a camera or a microphone?
No. It reads radio signal changes only. That is its main privacy advantage over a camera in a bedroom or bathroom.
Will it work if my parent has no smart devices?
Coverage generally improves with more connected devices, because each link is another path to measure. A home with a router and a phone gives the system very little to read.
Where WalledCare fits
WalledCare is a camera-free millimetre-wave radar presence sensor. It is mounted in a room and reports presence, movement, prolonged stillness and prolonged inactivity for that room. It answers a narrower, sharper question than Wi-Fi sensing: what is happening in this bathroom or this bedroom. Nothing is worn or charged, the unit needs an outlet rather than a working router relationship with an internet provider, and our own pages state that it is "Built & hosted in Canada". The cost of that resolution is one unit per room. It does not detect falls, does not measure breathing, and is not a medical device. See the WalledCare listing or the methodology.
Sources
- How Wi-Fi sensing became usable tech (MIT Technology Review, 2024). https://www.technologyreview.com/2024/02/27/1088154/wifi-sensing-tracking-movements/
- Design and Evaluation of Volunteer User Trials of Unobtrusive Vital Signs Monitoring for Older People in Care Using Wi-Fi CSI Sensing (IEEE Journal of Translational Engineering in Health and Medicine, via PMC, 2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC12599888/
- Software as a Medical Device (SaMD): Definition and Classification, Guidance Document (Health Canada, 2019). https://www.canada.ca/en/health-canada/services/drugs-health-products/medical-devices/application-information/guidance-documents/software-medical-device-guidance-document.html