Piezoelectric device for monitoring activity of vehicle driver

摘要

The measuring device comprises a piezoelectric device designed to measure frequency and amplitude esp. the frequency and amplitude of the respiration of the driver of a vehicle. The device consists of a layer of piezoelectric material (7) which is fitted within a protective sleeve (8) which may be a plastic envelope. To ensure the complete protection of the piezoelectric layer, the plastic envelope may in turn be attached to an electrical screening layer (9), such as a metallic mesh. The piezoelectric device may consist of a number of separate elements which are connected together head to tail in order to provide a series circuit, thus producing a changing voltage in response to the piezoelectric effect.