NOWATCH uses a photoplethysmography (PPG) sensor, electrodermal activity (by EDA), and an accelerometer to continuously capture your physiology.
The PPG sensor uses ambient, green, red, and infrared light to detect changes in blood volume circulation. Measures of heart rate, heart rate variability, breath rate, and blood oxygen concentration are derived from the PPG sensor with a high level of accuracy.
With EDA changes in the skin’s conductivity are recorded by sending a small, non-harmful current between two points on the wrist. The skin’s conductivity reflects the activity of the sympathetic nervous system, which is tightly linked to the stress system.
The accelerometer measures acceleration and is used to inform on movement.
The NOWATCH also contains a barometer and a temperature sensor, which will be supporting new features.