Piezoelectric Pressure Sensors as Switching Devices

In this paper, the applications where the piezoelectric pressure sensors using as switching devices were investigated. To begin with, the piezoelectric pressure sensor was designed and manufactured. The piezoelectric Lead Zirconate Titanate (PZT) disks with customized thickness, fabricated by the tape-casting process, were used in this sensor as sensing element because of its great piezoelectric properties. Two most widely used structure designs of the pressure sensors were compared and the PZT pressure sensor adopting unimorph structure was selected. Next, corresponding theoretical analysis was conducted according to the established unimorph structure model. Based on the analysis, several pressure sensors samples with improved sensitivity and simple structure ware fabricated. Using these pressure sensors, two experiment where the pressure sensors were used as switching devices were studied. First, one pressure sensor was connected to an Arduino UNO board to form a trigger switch, which was designed to control a DC motor. By properly designing program algorithms and adjust the control parameter, it is successfully realized to change the working state through touching the pressure sensor. Second, a dimmer switch which consists of two pressure sensors were designed. The dimmer switch was also connected with the Arduino board to adjust the brightness of a dimmable LED. A brightness gradient was designed in the control program, which makes different brightness levels achievable by touching different positions on the dimmer switch.