A sensor which works on the principle of piezoelectricity is known as a piezoelectric sensor. Where piezoelectricity is a phenomenon where electricity is generated if mechanical stress is applied to a material. [1] Not all materials have piezoelectric characteristics.

Figure 1: The Piezoelectric Sensor Mat [2]

The commonly measured physical quantities by a piezoelectric sensor are Acceleration and Pressure. Both pressure and acceleration sensors work on the same principle of piezoelectricity but the main difference between them is the way force is applied to their sensing element.

In the pressure sensor, a thin membrane is placed on a massive base to transfer the applied force to the piezoelectric element. Upon application of pressure on this thin membrane, the piezoelectric material gets loaded and starts generating electrical voltages. The produced voltage is proportional to the amount of pressure applied.

In accelerometers, seismic mass is attached to the crystal element to transfer the applied force to piezoelectric materials. When motion is applied, seismic mass load’s the piezoelectric material according to Newton’s second law of motion. The piezoelectric material generates charge used for calibration of motion.

An acceleration compensation element is used along with a pressure sensor as these sensors can pick up unwanted vibrations and show false readings.

For this purpose we here use piezoelectric sensors that use piezoelectric effect in order to measure acceleration, force, pressure by its conversion into electric signals. Which then notifies with making the buzzer On. [3] So whenever any Visitors arrive there is no need of any doorbell doormat can automatically detect visitor and notify on their behalf. With the Piezo sensor built-in, Mat is able to actively monitor any time whether there’s a change in pressure from someone or something standing or sitting on the Mat. It’s not only a doormat, either. It’s a weight touchy layer of smart foam that you can set under your doormat or practically anyplace in your home you need pressure-sensitive responses.

Smart home service is blooming in the virtue of development of sensor network technologies, so that delivering more convenient life style in our home. Lights, dish washers, coffee machines work according to context information such as user identity, his activity, weather, indoor temperature, and so on. Commercialized its applications are demonstrating various simple, useful use cases which is mainly focusing on in and-out scenarios. [4] These results from not only that users carry their cell phone with them since they leave their houses so that the service system can easily recognize their locations, but also that there is much miscellaneous work. Based on these scenarios, user localization technologies have been investigated. However, a large quantity of them has focused on whole floor sensing, which cause enormous installation cost and time. In this work, we propose a foot mat sensor which allows easy installation and market feasibility. This smart mat system is designed to be capable of capturing user identity information, building wireless sensor network, and transmitting the information to the central control system.

References:

1. https://www.elprocus.com/what-is-a-piezoelectric-sensor-circuit-specifications-and-applications/
2. https://www.semanticscholar.org/paper/An-optimal-design-for-piezoelectric-energy-system-Pisharody/ae441cdb28aea0c705f556595a81939d9827447e/figure/7
3. https://nevonprojects.com/peizo-based-visitor-sensing-welcome-mat/
4. https://www.quickcompany.in/patents/peizo-based-visitor-sensing-welcome-mat

Cite this article:

Vinotha D (2022), The Technology of Piezoelectric Sensor Mat, AnaTechMaz, pp. 67