Espressif ESP-WIFI-CSI software relies on the disturbance in the force WiFi signals between one or more ESP32 boards and a router to detect whether humans are present in a room, or even indoor positioning, providing a cost-effective solution since no sensors are needed.

Channel state information (CSI) leverages carrier signal strength, amplitude, phase, and signal delay indicators to reveal the signal scattering, reflection, and power attenuation phenomena that occur with the carrier as the transmission distance changes. This

A radar device the size of a Wi-Fi router could help continuously monitor Parkinson’s disease in patients from afar as they go about their lives at home. By using radio waves to track the gait of Parkinson’s patients, the device should help doctors assess the effectiveness of medications, see how the disease is progressing, and create better treatment plans.

Parkinson’s disease is a chronic, progressive brain disorder that affects motor function, causing tremors, impaired balance, and the risk of falls and injuries. There is no cure for it and patients rely on medications to control symptoms.

Researchers Train a Neural Network to Detect Human Occupancy by Sniffing Ambient Wi-Fi Signals
https://www.hackster.io/news/researchers-train-a-neural-network-to-detect-human-occupancy-by-sniffing-ambient-wi-fi-signals-21127327da3b

By monitoring the Wi-Fi signals in a room, and passing the data through a convolutional neural network, human presence can be detected.

A new study from University of Chicago and University of California, Santa Barbara researchers finds that external attackers can use inexpensive technology to turn these ambient signals into motion detectors, monitoring activity inside a building without being detected themselves.

With only a small, commercially available Wi-Fi receiver, an attacker from outside the target site can measure the strength of signals emitted from connected devices and monitor a site remotely for motion, sensing whether a room is occupied.

Researchers at MIT have developed a system that can read a person’s emotions, even hidden ones, at a distance.