The Bionic Ring determines when a person is sleeping by combining multiple physiological and motion-based signals captured through miniature sensors. These sensors work together to detect changes in body activity, heart rhythms, and blood oxygen that correspond to different sleep stages such as light, deep, and REM sleep.
Photoplethysmography (PPG) is the primary optical sensing technology used. It involves emitting light onto the skin and measuring variations in light absorption caused by blood flow changes. These variations allow the ring to estimate e.g. heart rate and blood oxygen saturation (SpO₂).
An Accelerometer, a tiny motion sensor continuously tracks physical movement. During sleep, general movement decreases significantly, and the accelerometer’s data helps differentiate between resting but awake states and actual sleep. Its readings are crucial in recognizing transitions between light and deep sleep or detecting brief awakenings during the night.