Patent attributes
An entrapment detecting system includes a detection portion provided at an opening/closing apparatus for detecting an acceleration thereof on the basis of an output from a piezoelectric sensor for outputting a voltage corresponding to the acceleration and a control portion for judging whether or not an object is entrapped by the opening/closing apparatus on the basis of a detected result of the detection portion. The detection portion includes a current control portion connected to the control portion in series as a closed circuit whereby electricity is supplied from the control portion to the current control portion. The current control portion changes a consumed current of the detection portion on the basis of the output from the piezoelectric sensor. The control portion judges whether or not the object is entrapped on the basis of the consumed current of the detection portion changed by the current control portion.