System and method for using a capacitive door edge sensor

摘要

A system and method for sensing capacitance at the edge of a movable barrier and for detecting an obstruction includes positioning a conductive member within or about a holder. A sensed capacitance between the conductive member and ground. A controller is coupled to the sensor. The controller determines whether an obstruction exists within a path of the barrier by analyzing the sensed capacitance. The conductive member and holder move away from a physical reference as the physical reference is approached such that the sensed capacitance between the conductive member and the physical reference remains below a predetermined threshold.