Abstract: A vibration sensor includes a piezoelectric crystal; and a base having an upper surface and a lower surface, the piezoelectric crystal attached to the upper surface of the base, the base defining a notch in at least one of the upper surface and the lower surface. Another embodiment of a vibration sensor includes a first piezoelectric crystal; a second piezoelectric crystal; a base attached to the first piezoelectric crystal on first side of the base and attached to the second piezoelectric crystal on a second side of the base opposite the first side of the base; a voltage amplifier in electrical communication to the first piezoelectric crystal; and a charge amplifier in electrical communication to the second piezoelectric crystal.

Abstract: An electronics package for use with a proximity probe is disclosed that is capable of being calibrated to work with any proximity probe and cable and that is capable of being programmed in the field. The electronic package establishes and measures a plurality of gaps between the proximity probe and a target. An amplifier is operatively coupled to the proximity probe and produces an output which is digitized, linearized and stored. A linear piecewise approximation technique is used to approximate the voltage at the output of the amplifier for gaps that were not measured.