The availability of hardware sensors on the smartphone. The sensors on a smartphone ranges from proximity and ambient light sensors, to accelerometer, gyroscopes and compass. These hardware sensors facilitate things like auto-brightness, position information etc.
Proximity, Light, Accelerometer, Compass, Gyroscope, Barometer, Fingerprint, Hall, Heart rate, Fingerprint sensor model - Synaptics-Validity VAL004A8-T
Proximity, Light, Accelerometer, Gyroscope, Magnetometer, Fingerprint, Hall, Fingerprint sensor model - Fingerprint Cards FPC1035
Proximity, Light, Accelerometer, Compass, Fingerprint