A Piezoelectric Flow Sensor for Wake-Up Switch of Wireless Sensor Network Node

Power management technology is a fundamental issue in wireless sensor network. In this paper, we propose a concept of a piezoelectric flow sensor for a wake-up switch of a wireless sensor node to reduce the power consumption. The sensor detects air flow change surrounding the wireless sensor node by using a cantilever with Pb(Zr, Ti)O₃ (PZT) thin film. We fabricated a prototype of the flow sensor and measured the relationship between the flow velocity change and the piezoelectric voltage of the cantilever. The sensor responded when the flow velocity changed. The output voltage increases with the increase of the flow velocity change.

I. Introduction

Recently, advances in micro-electro-mechanical systems (MEMS) technology have enabled integration and miniaturization of physical sensors, microcontrollers, and radio interfaces on a chip for wireless sensor network node. Wireless sensor network (WSN) has attracted widespread attention with its practical values. WSN is used for health monitoring [1], [2], environmental monitoring [3], [4], and so on. In many applications, wireless sensor nodes are deployed with limited battery power. It is difficult to replace batteries frequently due to the cost for replacement of battery on a huge number of senor nodes, hard-to-reach installation location, and other factors. Power management technology to utilize the power of node efficiently is one of the most crucial technologies in WSNs.