How Sensors Collect, Process, and Track Data in Wearable Devices

A smartwatch can tell you that your heart rate is 78 beats per minute, that you've walked 6,421 steps, or that you slept for 7 hours last night. All of these numbers appear simple on the screen, but behind each one is a surprisingly long chain of measurements and calculations. Your watch doesn't actually see a "step" or directly measure "sleep."...