Design, Assembly and Testing of a Novel Piezoelectric Geophone Based on PVDF Film

Abstract

A piezoelectric geophone is a vibration transducer that converts mechanical vibrations into electrical signals via the piezoelectric effect. At present, the commonly used sensitive component of the conventional piezoelectric geophone is piezoelectric ceramic (PZT) material, which has low structural flexibility and high natural frequency. This paper reports a piezoelectric geophone based on polyvinylidene fluoride (PVDF) film with a sensitive unit composed of PVDF film and spiral cantilever beam, which can increase the sensitivity and reduce the low-frequency cutoff frequency. Firstly, the PVDF piezoelectric film is introduced, and the sensitive unit with PVDF piezoelectric film and spiral cantilever beam is designed. Secondly, the signal conditioning circuit and the digital module circuit are designed according to the characteristics of the detector and the test environment. Finally, the performance tests and fabrication of the geophone are carried out. The results indicate that the piezoelectric geophone has a stable sensitivity of 230 mV/m/s2 in the range of 4–90 Hz, which are superior to the existing piezoelectric geophone.