alt Hacker NewsThis 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.