Abstract: The preferred arrangement utilizes a magnet suspended at the center of an elastic cord over a pickup coil. Movement of the magnet is sensed by the coil in that signals are generated by such movement. The signals are processed in the combination of a time delay circuit and a comparator to provide an output which is a measure of acceleration of the element on which the elastic cord is mounted and, in one form, by a measure of jerk in a similar time delay circuit and comparator combination.