A Piezoelectric Pulse Generator and FM Transmission Circuit for Self-Powered BSN Nodes

This paper presents a piezoelectric pulse generator for body sensing and wireless transmission. A steel rolling ball is used as a proof mass to provide a smooth motion excited by non-harmonic external vibrations. In addition, the proof mass in this prototype is implemented to achieve both impulse excitation of the piezoelectric cantilever by magnetic coupling, and self-synchronous switching. A new actuation mechanism to pre-bias a piezoelectric cantilever passively is demonstrated which enhances the energy extracted. Experimental results are presented to compare between the pre-biased and unbiased cases, showing 76% more extracted energy in the pre-biased case. A transmitter is designed which encodes the sensor signal by frequency modulation, to demonstrate the feasibility of building a self-powered body sensor network (BSN) node based on the demonstrated piezoelectric pulse generator.