Wi Fi Routers Detect People in a Room

Intriguing capability, unexpected. 

Wi-Fi Routers Can Detect Human Locations, Poses Within a Room

Tom's Hardware, Mark Tyson, January 18, 2023

Carnegie Mellon University scientists have been testing a system that uses Wi-Fi signals to detect the positions and poses of people in a room. The researchers positioned TP-Link Archer A7 AC1750 Wi-Fi routers at either end of the room, while algorithms generated wireframe models of people in the room by analyzing the signal interference the people caused. The researchers based the perception system on Wi-Fi signal channel-state-information, or the ratio between transmitted and received signal waves. A computer vision-capable neural network architecture processes this data to execute dense pose estimation; the researchers deconstructed the human form into 24 segments to accelerate wireframe representation. They claim the wireframes' position and pose estimates are as good as those generated by certain "image-based approaches."  ... '