International Journal of Computer Science and Engineering Communications- IJCSEC. Vol.2,Issue.1,February,2014. ISSN:2347–8586 100 Hall Effect Sensor Based Portable Tachometer for RPM Measurement Kathirvelan J, Babu Varghese, Ubaid A Ponnary, Fajas Kamar, Renju Thomas Jacob School of Electronics Engineering, VIT University, Vellore. India. babualumkan@gmail.com 1 ,ubaidponnary@gmail.com 2 ,fajazz@gmail.com 3 , renjujacob_88@yahoo.co.in 4 ABSTRACT Hall effect sensors has a wide variety of applications in position sensing, angular measurement, speed measurement...Etc. Reference[1] is a velocity measurement by using linear hall effect sensor. Basically Hall Effect sensor is a magnetic field detector which detects the changes in field strength .This paper tries to explain a tachometer based on Hall Effect sensor which is accurate, portable and contactless. By using latched Hall Effect sensor, rotational speed can be measured by counting the number of pulses per revolution. The tachometer shaft is made in contact with the motor shaft whose speed is to be measured and a number of magnets are mounted on tachometer shaft. Hall sensor is positioned stationary in such a way that it will closely face the rotating magnets. Since the output is in the form of pulses it becomes easy to manipulate the data. We could develop a model which counts the rotation and which handle high speeds up to 5000-6000 rpm. With the help of a microcontroller speed can be calculated and displayed. From the conventional analog tachometer the Hall Effect based tachometer is expected to give wide ranges of operating speed and increased accuracy. Key Words: Hall Effect, Lorentz Force, Tachometer, Revolution per Minute. INTRODUCTION Hall Effect is a phenomenon that occurs in conductor carrying a current when it is placed in a magnetic field perpendicular to the current. The charge carrier in the conductor become deflected by the magnetic field and give rise to an electric field(Hall field)that is perpendicular to both current and magnetic field. If current density ‘Jx’ is along X and the magnetic field, ‘Bz’, is along Z, then the Hall field is either along +Y or –Y depending on the polarity of the charge carriers in the material. The force exerted on the charge carriers is given by Lorentz equation. The Lorentz force is the force experienced by a moving charge in a magnetic field. When a charge q is moving with a velocity v in a magnetic field B, within the presence of an electric field E, then it experience a force F, that is proportional t o magnitude of the charge q, its velocity v, and the field B such that, Paper Type: Article. Category: Electronics Corresponding Author: Renju Thomas Jacob, Email ID: renjujacob_88@yahoo.co.in scientistlink.com