OCCUPANT SENSOR

摘要

An electric field sensor (12) comprising at least one electrode (26) mountable within a seat (14) is operatively coupled to a sensing circuit (38), which applies an oscillating signal (28), comprising at least one frequency or at least one pulse, to at least one electrode (26) and generates a signal (32) responsive to at least one electric-field-influencing property of an object proximate to the electric field sensor (12). At least one frequency or pulse width of the applied signal (28) are adapted to be at most weakly responsive to a wetting condition of the seat (14). A method of sensing an occupant comprises placing at least one electrode (12) within a seat (14) of a motor vehicle (16), applying an oscillating signal (28) to at least one electrode, measuring (1112) the amplitude (1026) and phase (1038) of a signal (26) responsive to the at least one electrode (26), rotating (1116) the measured amplitude (1026) and phase (1038), compensating (1118) the rotated amplitude by a value responsive to the rotated phase, and comparing (1120) the compensated amplitude with a threshold.