The Piezo Vibration Sensor is based on piezoelectric transducer. It is well known that  piezoelectric materials responds to strain (deflection) changes or applied force by generating a measurable output voltage.  This output voltage is proportional to the strength of shock or vibration.  So you can measure and characterize the vibration.

Specification

• Working Voltage: 3.3V or 5V
• Working Current: <1mA
• Operating Temperature Range: -10 ℃ ~ + 70 ℃
• Interface Type: Analog Output
• Size: 30mm x 23mm
• Weight: 5g

Pin definition

•  S: output signal from the sensor (connected to arduino analog input)
• +:  Voltage supply (VCC = 3.3 - 5)
•  -: ground (GND)

Arduino Sample Code