Environmental Noise Harvester Using a Helmholtz Resonator and Piezoelectric Transducer

This work represents a guideline for designing, analyzing, and implementing a compact, low-cost, lightweight, and portable system that harvests energy from environmental noise at different locations. Considering that the proposed energy harvesting system (EHS) is based on a piezoelectric transducer (PZT) embedded in a Helmholtz resonator (HR), we first characterize the noise at four different locations selecting the most suitable ones for energy harvesting. Then, we electrically analyze and describe the PZT determining its resonance frequency. Subsequently, by using this frequency, we perform the sizing of the HR. Thus, we analyze the behavior of the implemented EHS under controlled and actual conditions. In controlled conditions, we determine the gain of the implemented EHS using a pure sinusoidal signal at 500 Hz and a pink noise signal. In actual conditions, we measured its gain considering two different locations. We observed that under controlled conditions, the implemented EHS achieved a gain between 168.3% and 200.3%, and under actual conditions, its gain was 159.5% in the traffic zone and 597.7% in the music zone. In addition, for the HR modeling and design, we show that its theoretical gain corresponds to its simulation gain but differs from its experimental gain due to the used material and manufacturing. Finally, we show that the implemented EHS performs similarly or better than other more sophisticated systems or systems with more piezoelectric elements.