International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 02 | Feb -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 1693 Sensitivity of the MEMS based Piezoresistive Wind Speed Sensor with Comparative Study of Different Shapes of Paddles Amandeeep Kaur Dhonkal 1 , Vimal Agarwal 2 , Kanchan Sengar 3 1 Scholar, Dept. of ECE, JECRC University, Jaipur, Rajasthan, India 2 Associate Professor, Dean Academics, Apex Institute of Technology, Jaipur, Rajasthan, India 3 Assistant Professor, Dept. of ECE, JECRC University, Jaipur, Rajasthan, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - MEMS (Micro-Electro-mechanical System) technology is one of the prominent technologies which has many advantages such as high accuracy, low cost and small size. Conventional rectangular beam cantilever are based on detection of the surface stress of the beam, generated due to the speed of the wind. Stress induced in the microcantilever beam is affected by the area of the cantilever. In this paper we have designed a piezoresistive microcantilever based wind speed sensor. The finite element method (FEM) is used to investigate the shape distortion and stress dissemination. The software Comsol multiphysics 4.4 is used to examine the linking characteristics between the material and the fluid. A comparative study for different shapes of paddle such as hexagonal, rectangular and triangular has been performed. The effect of different shapes on the stress induced has been compared, keeping the area of the shapes constant. The simulation results show that the triangular shaped paddle results in higher sensitivity of the sensor. The sensitivity of the respective wind speed sensor comes out to be 0.20402825 mV/ms -1 . Key Words: MEMS, FEM, Microcantilever, Paddles, Differential pressure. 1. INTRODUCTION Microcantilever is a component which is widely used in micro system devices and provides a good platform for various sensitive sensors. A cantilever is a device which is fixed on one end and movable on the other [1, 2]. Load is applied at the free end of the cantilever that results stress at the surface of the cantilever. A micro cantilever detects the change occurred in stress when the cantilever bends or change in the frequency due to vibration, hence widely used as physical, chemical or biological sensor. Micro cantilevers have become so popular from past few years because of their selectivity, high sensitivity and flexibility of on-chip circuits and ease of fabrication. It provides a wide range in industrial applications due to convenience to regulate and readily adjustable into unified electromechanical system. Micro cantilever sensors can be used in any medium such as air, vacuum or liquid. This paper provides details about the finite element method (FEM) to acquire the accurate performance of microcantilever sensor with different shapes of paddles such as hexagon, rectangle and triangle. Finite element method (FEM) is used for simulations and analytical calculations for various shapes and geometries of the cantilever paddles [3, 4]. Different shapes of paddle of the cantilever beam using structural mechanics module of Comsol multiphysics 4.4 has been designed and simulated. The result of stress induced due to the different shapes are compared to obtain the sensitivity of the sensor 2. DESIGN AND OPERATING PRINCIPLE 2.1 Basic Structure Static and dynamic characteristics are firstly considered for designing a micro-sensor. The structure of the microcantilever should have enough strength and should be suitable for external connections and easy to install. Fig -1: Structure of the sensor As shown in Fig -1, the sensor consists of pedestal, cantilever and triangular shaped paddle. Pedestal, cantilever and triangular shaped paddle have the same thickness. By placing the paddle at the free end of the cantilever, the sensitivity can be enhanced. Poly-Si is used as a material for the structure of the sensor. Then, a piezoresistive layer of the P type Si has been placed over the Poly-Si layer. One out of four piezoresistor is incorporated on the cantilever and a Wheatstone bridge is formed, as shown in the Fig -2.