Piezoelectric crystals have an interesting property that make them unique and powerful as a sensor. On the sensor side, when a piezoelectric crystal is deformed, it generates an output EMF (Electromagnetic Field). This characteristic is the basis for the vast majority of vibration sensors as well as many popular audio input sensors.
The industry standard for this type of sensor is a two-wire interface that, depending on the manufacturer, may be called ICP, IEPE or a variety of other names.
The DNA-AI-211 4-channel IEPE / ICP Vibration Sensor Interface
The common thread is that the two-wire interface provided power via a constant current source (typically between 1 mA and 4 mA) and then returns the output voltage on top of the current source. See the DNA-AI-211 as an example of a four-channel ICP/IEPE interface.
Data Acquisition Systems Engineering 