What WiFi Knows About Your Body
20 days ago
- WiFi signals can extract heart rate, breathing pattern, and movement data through walls by analyzing reflected radio waves, without the subject's knowledge or consent.
- The author built a functional heart rate sensor using cheap hardware (€25) and AI assistance, with no prior signal processing expertise.
- WiFi sensing works via Channel State Information (CSI), measuring how body movements distort reflections of the signal.
- Research advances include high-accuracy breathing and heart rate detection, gait recognition, and even body pose estimation through walls.
- The new IEEE 802.11bf standard formalizes sensing capabilities but lacks privacy protections, consent mechanisms, or opt-out options.
- WiFi sensing often enters the market through care applications (baby monitoring, elderly fall detection, sleep apnea diagnosis) but can be used for surveillance.
- The author's system inadvertently violated GDPR by sensing a stranger's heartbeat through a wall without consent, highlighting enforcement challenges due to lack of traces.
- Future capabilities include keystroke inference from finger micro-movements via WiFi, currently in early research stages.
- The 'Partition' art project uses WiFi-sensed heart rate to drive a pen plotter in real time, with consent at the peephole but no data storage.
- Two walls have fallen: the physical walls of homes and the boundary of the skin, making internal biometrics externally readable without permission.