<p>➀ Researchers at UC Santa Cruz developed Pulse Fi, a system using WiFi signals to measure heart rates without wearables, achieving ≈0.5 BPM error across multiple body positions;</p><p>➁ The low-cost system combines ESP32 chips ($5-$10) and Raspberry Pi with machine learning to filter heartbeat signals from WiFi variations, working up to 3 meters away;</p><p>➂ Trained using oximeter-correlated datasets, the technology enables accessible health monitoring for homes and resource-limited environments.</p>