Meg Duff

Over a decade ago, Neal Patwari lay in a hospital bed, carefully timing his breathing. Around him, 20 wireless transceivers stood sentry. As Patwari’s chest rose and fell, their electromagnetic waves rippled around him. Patwari, now a professor at Washington University in St. Louis, had just demonstrated that those ripples could reveal his breathing patterns. A few years later, researchers from MIT were building a startup around the idea of using Wi-Fi signals to detect falls.