Infra-red detection and positioning system
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Introduction
Infra-red detection and positioning system is used to locate and display the position of IR signal source. For tracking purpose IR eye is used as a receiver and any IR emitting terminal as transmitter. It is easy to deploy and give a large range of coverage. The system finds its applications in museums and such places were directional guidance is required for visitors. It can also be used in tracking objects which carry active tags that emits IR signal which are received by stationary mounters.


Circuit Principle
In this chapter topics including basic block diagram, circuit diagram, working and components used are discussed and explained. Block diagram includes the basic building blocks for developing the infra-red detection and positioning system using serial port.After that circuit diagram and its workingis described. Further, various components used like optocoupler, stepper motor, microcontroller 89C2051, line driver MAX232 and their working is explained.


Optocoupler:
An optocoupler (or an optoelectronic coupler) is basically an interface between two circuits which operate at (usually) different voltage levels. The key advantage of an optocoupler is the electrical isolation between the input and output circuits. With an optocoupler, the only contact between the input and the output is a beam of light. Because of this it is possible to have an insulation resistance between the two circuits in the thousands of megaohms. Isolation like this is useful in high voltage applications where the potentials of two circuits may differ by several thousand volts.The most common industrial use of the optocouplers (or optically-coupled isolators) is as a signal converter between high-voltage pilot devices (limit switches etc) and low voltage solid-state logic circuits.