Comment by vel0city
1 month ago
This technology doesn't rely on you actually having a WiFi device on you. It can detect presence/motion by changes to the standing waves of the EM propagation throughout the room.
As the salty water meatbags move from room to room we change how the reflections and scattering patterns of 2.4 and 5GHz waves move. Studying these changes and some calibration, you can even determine small changes (like is the person on the left side of the room breathing, are they standing or prone, etc).
In their docs, they show using the WiFi connection from a printer to determine motion sensing and have the option to exclude pets.
im very skeptical of the accuracy claimed. The layout and complexity of objects in most homes to do this is way to awkward to work reliably.
For someone breathing or a heartbeat you need much higher GHz signal. Usually this is done at 30ghz to 60ghz. The power flux leaving the antenna has an inverse square drop off rate which makes this basically impractical unless your standing directly in front of it.
I have personally tested wifi imaging from a cheap old 2.4Ghz linksys router that was accurate enough to tell if my hand was open or closed, maybe 10 years ago.
I do agree some of these claims are pretty extreme. I wonder if it does work what the reliability of things like breathing and heartbeats. FWIW, some of these systems do incorporate 60GHz signals in their analysis, but as you mention dealing with 60GHz is incredibly challenging even in something like a residential building.
I'd really like to actually see it in person to really grasp the limitations.
Is 60GHz not part of the standard now? Only a matter of consumer hardware support.
I don't think 60GHz is required on WiFi 7 which includes a lot of sensing, but I'm open to be proven wrong.