Sleep trackers use your resting heart rate, heart rate variability and breathing data to estimate how long you sleep and how much time you spend in each stage.

The BPM Vision doesn't actually work with Withings' Cardio Check-Up—you need an ECG-enabled Withings tracker, like the ...

Optical sensors are a broad class of device for detecting light intensity. This can be just a simple component for notifying when ambient light levels rise above or fall below a prescribed level, or a ...