CHAPTER ONE
INTRODUCTION
The industrial batch counter is an electronic and electrical device that handles the counting and controls the flow of individuals using an automated slide door that allows access only when the administrator permits. The technique involved in the design is a simple sensor unit that opens and closes the door when someone obstructs the light path. These parameters can be used to determine when someone has moved in or out of the conference hall (for instance). The light sensing type involves monitoring the unit with photon or optical devices; this consists of the encoder (transmission path or the source of energy) and the decoder (receiver unit that converts the light intensity to electrical signal). An LED emitter, combined with a photo detector (Light Dependent Resistor, photo transistor or infrared sensing diode) in proximity, form a very useful object called opto-coupler or opto-isolator. When the opto coupler is obstructed, the door opens and the display shows an increase or decrease of individuals in the room (depending on the path followed).