Comment by er0k

This is nothing new. Wifi signals have been used to detect objects, people and animals, gait analysis[1], read keystrokes[2], monitor breathing and heart rates[3], "hear" conversations[4], etc for at least a decade now.

https://news.ycombinator.com/item?id=12353605

https://www.theatlantic.com/technology/archive/2016/08/wi-fi...

https://archive.is/XnHUV

1: https://ieeexplore.ieee.org/document/7457075

2: https://dl.acm.org/doi/10.1145/2789168.2790109

3: https://archive.is/mFSDq

4: https://archive.is/sNVcM