Pulse wave sensor for non-intrusive driver's drowsiness detection.

This research proposes a PVDF film pulse wave sensor for use in driver's drowsiness detection. The sensor non-intrusively measures heart pulse wave from driver's palm and an adaptive filter is employed to cancel the measurement noise aroused by the changing of gripping force. Experimental results show clear pulse wave signals can be obtained. Two-hour driving simulation is performed for drowsiness detection tests. The low frequency to high frequency (LF/HF ratio) is calculated from power spectrum density (PSD) of subjects' heart rate time series. The LF/HF ratio shows decreasing trends as subjects go from awake to drowsy.