Design And Construction Of Full Duplex Intercom

ABSTRACT

This project is titled design and construction of full duplex intercom. It is designed to meet up with the communication demand in our homes, offices and industries.

Full duplex Intercom is a private telecommunication system that allows typically two or more locations to communicate with each other like telephone does. This system can be used as an intercom and door phone. You can use intercom systems from your house to house gate/door to screen visitors to your house. Full duplex intercom system allows the users of the system to communicate with each other on both directions without any controls (like transmit button pushing etc.)

This system allows operating two intercom stations leaving the operator free of using his or her hands in some other occupation, thus avoiding the usual “push-to-talk” operation modes. No complex changeover switching is required: the two units are connected together by means of s thin screened cable. With full duplex intercom, one host transmits, one receives but neither host can both transmit and receive. A microphone will transmit a message to a receiving speaker direction. This system composed of two amplifiers- one for transmitting and the other for receiving.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• PROBLEM STATEMENT
• AIM OF THE PROJECT
• OBJECTIVE OF THE PROJECT
• PURPOSE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• ADVANTAGES OF THE PROJECT
• SCOPE OF THE PROJECT
• METHODOLOGY
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• REVIEW OF THE STUDY
• DESCRITION OF AN INTERCOM
• DEFINITION OF BASIC INTERCOM SYSTEM TERMS
• TYPES OF INTERCOM
• HISTORICAL BACKGROUND OF INTERCOM SYSTEMS

CHAPTER THREE

METHODOLOGY

• SYSTEM BLOCK DIAGRAM
• DESCRIPTION OF SYSTEM BLOCKS
• CIRCUIT DIAGRAM OF THE SYSTEM
• PARTS LIST
• CIRCUIT DESCRIPTION
• CIRCUIT DESCRIPTION
• MAJOR COMPONENT’S DESCRIPTION

CHAPTER FOUR

• IMPLEMENTATION, TESTING AND RESULTS
• CONSTRUCTION PROCEDURE AND TESTING
• INSTALLATION OF THE COMPLET DESIGN
• CASING AND PACKAGING
• ASSEMBLING OF SECTIONS
• TESTING OF SYSTEM OPERATION
• COST ANALYSIS

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.0                                          INTRODUCTION

1.1                          BACKGROUND OF THE PROJECT

Full duplex intercom system allows the users of the system to communicate with each other on both directions without any controls (like transmit button pushing etc.).

This system allows operating two intercom stations leaving the operator free of using his or her hands in some other occupation, thus avoiding the usual “push-to-talk” operation modes. No complex changeover switching is required: the two units are connected together by means of s thin screened cable. With full duplex intercom, one host transmits, one receives but neither host can both transmit and receive. A microphone will transmit a message to a receiving speaker direction. This system composed of two amplifiers- one for transmitting and the other for receiving.

Implementation of full duplex intercom in generally much more complicated than implementing half duplex intercom, especially if you need to communicate with just few wires (a pair of wires) and want speakerphone like operation without handset. For this kind of full-duplex system you will generally need an amplifier at the gate like you have now but you will also need a circuit that isolates the gate circuit’s input from its own output, like a speaker phone does.

Intercom systems used in TV and stage productions are usually headset type intercoms connected to one line using party line arrangement. The primary use of this type of system is in live or media productions where (for example) the video director speaks to the camera operators, or where the stage manager speaks to the stage hands and lighting operator, etc. This type of intercom allows communications in two directions between anyone on the line in that basis that everyone hears everything.

This kind of intercom systems are frequently referred to as 2-wire although this term is misleading since the stations are connected together using 2-conductor shielded microphone cable, and the shield is very much a conductor. This connector is typically used to carry the party line voice in one wire and the station operating power on another wire. The ground is common for both of them. This kind of intercom systems are sometimes called “talkback” systems.

1.2                           STATEMENT OF THE PROBLEM

In a business organization, shops, stores, homes etc, many people find it difficult and stressful in relating/ delivering information between each other within a particular building. The servant finds it laborious going to the boss always whenever he / she has information to deliver or wants to carry out action(s) with respect to the master’s authority. Parents within a home are even forced to walk down to the child’s room whenever need arises. As a matter of fact, reaction to information is delayed.

Therefore, this project work is to address this issue, looking forward to eliminating the stressful manpower involved and to facilitate information delivery, making communication easier.

1.3                                    AIM OF THE PROJECT

The main aim of this work is to build a device that can be used to communicate with people inside and outside a building.

1.4                             OBJECTIVE OF THE PROJECT

At the end of this work, student involved shall be able:

(1) construct an intercom system that will help two persons or more to communicate with each other within a particular domain, like offices homes, warehouse e.t.c.

(2) To build a telephone that will transmit signal via a medium at no cost.

(3) To immensely help the engineering students understand the technology behind two way simple intercom and its practical development.

1.5                               PURPOSE OF THE PROJECT

The purpose of this work is to establish a means of easy flow of communication within a building or premises at no cost.

1.6                              SIGNIFICANT OF THE STUDY

The design and construction of two way intercom system will help students or individual to understand the basic knowledge of intercommunication industries, also it’s a means to replace man’s labour and stress of walking over a given premises for information delivery. This intercom system can be used as a door phone, connecting from the house to the door to screen visitors to the house. The wife, after preparing dinner, can through this system call on the husband in his bedroom to the dinner table. Generally, intercom system can be used for message broadcast (in case of multi-channel intercom), as door phone, monitoring etc.

1.7              ADVANTAGES OF FULL DUPLEX INTERCOM

The advantages of this system include relatively easy setup, simple operation, use of common cabling (standard microphone cables), portability, and clear and reliable communications. Full duplex intercoms are standard equipment at performing facilities, allowing communications among the lighting and stage-production staff. Touring sound and lighting companies will carry these systems with them for concerts and events. Locations such as community theaters, school and college auditoriums, sporting and racing venues also use party-line intercom systems.

1.8                                       SCOPEOF PROJECT

The scope of this project work “ full duplex intercom system” is to limited to the design, construction and test on a two station simple intercom system with specification that;

1. The demodulator should operate with a minimum distortion while producing an adequate output
2. The small signal amplifier must provide an undistorted signal into the buffer amplifier to be able to drive a speaker of 8 ohms impedance.

• A 9 volt d.c power supply is to be design and employed to power the simple intercom for operation at each station.

1. Result shall fully be discussed while suggestions for further study made.

1.9                                        PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to a of a two station wired wired intercom. In this chapter, the background, significance, objective limitation and problem of a two station wired intercom were discussed.

Chapter two is on literature review of a two station wired intercom. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.