What is a mmWave radar sensor, and why it can go where a camera can't

How does a mmWave radar sensor work?

Send out a radio wave. Time the echo. Most room sensors use FMCW radar (frequency-modulated continuous-wave): the sensor sends a tone that slides up in pitch, a "chirp", and compares it with the echo. From that it works out how far away an object is and how fast it is moving (Texas Instruments, 2020).

"mmWave" means the wavelength is "in the millimeter range" (Texas Instruments, 2020). Short waves bounce off small things, like a hand on a blanket. Infineon says its radar sensors can detect "even the smallest movements invisible to the human eye" (Infineon, accessed 2026). That is why radar can tell a person sitting still from an empty chair, where a basic motion detector cannot.

Infineon says 24 GHz sensors "have lower free space attenuation, which makes them ideally suited for outdoor and long detection range applications", while 60 GHz systems "offer a better range resolution" at short range. Strictly, 24 GHz sits just below the millimetre-wave band, but the industry groups these sensors together.

What can a radar sensor tell you, and what can't it?

It can tell you someone is in the room, even sitting or lying still; that they are moving, and roughly how much; that they have been still a long time; and that they have left.

It cannot tell you:

• Who the person is. Radar sees a reflecting shape, not a face.
• What they look like or what they said. There is no image and no audio.
• Why they stopped moving. A nap and a collapse look the same to a presence sensor.
• Reliably, that a fall happened. A 2024 lab prototype using three radars reported 96.3% fall-detection accuracy on over 300 minutes of data, about 360,000 frames (Sensors, 2024). A 2024 survey of 74 research papers stressed "the necessity for a clear definition of falls and appropriate detection criteria", and pointed to real-world application as a direction still to be worked out (IEEE Robotics & Automation Magazine, 2024).

Infineon lists "the monitoring of vital functions (respiration rate and heartbeat)" among 60 GHz use cases (Infineon, accessed 2026). That is what a chip can attempt. Whether a product does it, and how well, is a question for each vendor.

Why can it go where a camera can't?

Its raw output is distances, speeds and angles. Researchers put it this way: "Compared to wearables and camera methods, Millimeter-Wave radar is not plagued by mobility inconveniences, lighting conditions, or privacy issues" (Sensors, 2024). So it can go in a bathroom or bedroom, and it needs no light.

Radar is not magic. Pets, fans and moving curtains can register as movement. Single-chip sensors usually cannot tell two people apart; the lab system above needed three radars for that (Sensors, 2024). And the activity records are still personal information, even with no image or audio.

Radar vs PIR vs camera vs pendant

A pendant is the only option here that lets a person call for help on purpose.

Is it legal in Canada?

Low-power radar sensors are licence-exempt under ISED's RSS-210. Annex J covers licence-exempt field disturbance sensors at 57 to 71 GHz; radar devices are a subcategory of field disturbance sensor. A 24 GHz sensor falls under Annex F.1 (24.075 to 24.175 GHz) or the general limits in Annex B.10 (24 to 24.25 GHz), depending on how it is certified (ISED, 2024). Exposure is governed by Safety Code 6, whose limits "protect against all established adverse health effects" (Health Canada, 2015).

"Certified to RSS-210" is not "Health Canada approved". Health Canada does not certify consumer radar sensors. Products sold as medical devices need a licence, and its guidance says "It is the intended use of the device that primarily determines the class of the device" (Health Canada, 2015). More in Is mmWave radar safe?.

Radar sensors marketed for elderly care

Disclosure: WalledCare Learn is published by Moneli Automation, maker of WalledCare. Listings are not paid; claims are quoted as the vendor words them, checked 2026-09-06. Canadian availability is confirmed only for WalledCare. How we check listings.

• WalledCare (Moneli Automation). Camera-free mmWave presence sensor. Its page says it "is not a medical device and does not detect falls" and is "Built & hosted in Canada". (walledcare.com)
• Vayyar Care. "Receive immediate alerts when a resident experiences a fall." No cameras, no wearables. (vayyar.com/care)
• Milesight VS373. A 60 GHz radar fall sensor advertising 99% accuracy, footnoted "The part of the data are all derived from laboratory conditions, and there may be deviations in actual use". (milesight.com)
• Aqara FP2. Presence sensor with a fall alert; "not a medical device, and can only be used for notification purposes". (aqara.com)

Treat every accuracy figure as marketing until you see who tested it and on how many people.

What does the evidence say?

Plainly: it is thin. A 2025 systematic review of 33 studies in hospitals and long-term care facilities found sensor systems achieved "high usability (>80% acceptance)" but "did not consistently reduce fall incidence", and that "frequent false alarms contribute to alarm fatigue" (Medicina, 2025). It did not cover private homes, so it is only indirect evidence for home use.

A 2025 Canadian randomized trial of passive home monitoring followed 313 client-caregiver pairs in Ontario and Nova Scotia and found no significant effect on staying home (Ontario HR 0.7, P=.30; Nova Scotia HR 1.1, P=.90). It used mixed sensors, including cameras, not radar alone (JMIR Aging, 2025). A 2023 Canadian scoping review said "more high-quality research on this topic is needed" (Canadian Journal on Aging, 2023).

The need is real. "Between 2017 and 2022, deaths due to falls increased 51% in adults aged 65 years and older", from 4,752 to 7,182, Yukon excluded (Health Infobase, PHAC, updated 2025). No sensor has yet been shown to change those numbers. A sensor gives you information; people still have to act on it. More in falls in Canada: the statistics.

What to do next

• If your worry is a fall and an immediate call for help, start with a monitored pendant. Life Alert alternatives in Canada sets out what is sold here and what each option misses.
• If your worry is a bathroom or a bedroom where a camera is refused, compare the sensor types room by room in PIR vs mmWave vs Wi-Fi vs acoustic.
• Whatever you are looking at, ask the vendor for its ISED certification number, and ask who tested any accuracy figure and on how many people.