How do biometric sensors work in smartwatches?

27 Haz 02:53

Smartwatch biometric measurements are typically done using PPG (photoplethysmography) sensors. These sensors emit green or infrared light onto the skin, allowing for regular readings of heart rate and blood oxygen levels (SpO₂). As I noticed while using my Xiaomi Mi Band 6, the sensors track heart rhythm changes by detecting minimal vibrations and analyzing light reflections. Some models also include ECG (electrocardiography) modules, which directly correlate electrical signals with heart activity. As for accuracy, I’ve observed that devices perform continuous calibration and algorithmic adjustments. For instance, fitness trackers use barometric pressure sensors to support oxygen level measurements, making them more resistant to errors caused by altitude or movement. I once noticed that during a high-altitude hike, the sensor readings aligned perfectly with my shortness of breath. These devices also use machine learning models in data analysis to account for individual differences—I learned that a friend of mine, who’s the same age, has a slower heart rate, and the sensor automatically adjusted for that.