Description
ABSTRACT
C Intercoms are generally mounted permanently in buildings and vehicles. Intercoms can incorporate connections to public address loudspeaker systems, walkie talkies, telephones, and to other intercom systems. Some intercom systems incorporate control of devices such as signal lights and door latches
TABLE OF CONTENTS
COVER PAGE
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWELDGEMENT
ABSTRACT
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE PROJECT
- AIM/OBJECTIVE OF THE PROJECT
- PURPOSE OF THE PROJECT
- BENEFIT OF THE PROJECT
- SCOPE OF THE PROJECT
- SIGNIFICANCE OF THE PROJECT
- DEFINITION OF TERMS
- APPLICATION OF THE PROJECT
- PROJECT ORGANISATION
CHAPTER TWO
LITERATURE REVIEW
- REVIEW OF DIFFERENT TYPES OF INTERCOM
- HISTORICAL BACKGROUND OF INTERCOM SYSTEMS
- WIRELESS AND WIRED HOME INTERCOM SYSTEM
CHAPTER THREE
SYSTEM DESIGN
- SYSTEM BLOCK DIAGRAM
- BLOCK DESCRIPTION
- WIRING DIAGRAM
- INTERCOM CIRCUIT SCHEMATIC DIAGRAM
- COMPONENTS LIST
- CIRCUIT DESCRIPTIONT
- SYSTEM OPERATION
- MAJOR COMPONENT’S DESCRIPTION
CHAPTER FOUR
TESTING AND RESULTS
- CONSTRUCTION PROCEDURE AND TESTING
- CASING AND PACKAGING
- ASSEMBLING OF SECTIONS
- PACKAGING
- MOUNTING PROCEDURE
- PROBLEM ENCOUNTERED
CHAPTER FIVE
- CONCLUSION
- RECOMMENDATION
- REFERENCES
CHAPTER ONE
1.1 INTRODUCTION / BACKGROUND
Human to human communication is an essential part of our everyday activities. Advances in communication technology have enabled any-time-anywhere connection between people. There are a wide variety of devices to communicate with family, friends and workgroup members who are distributed geographically. Cellular phones are used at the working places, stores etc. to call home to be reminded of what is needed or when one will be late to work, meeting etc.
The purpose of a communication system is to transfer information between two or more points. In general, a communications system requires three things namely; a transmitter, a propagation medium, and a receiver. The information to be transferred may be in analog form (example, voice or audio) as in the case of this study where voice is the source of information, or in digital form (computer data, digitalized voice, and so on). The transmitter must have some means of superimposing this information onto its output signal (modulation). The modulated transmitter signal must pass through a propagation medium to a receiver. The propagation medium may be free space, an RF transmission line, or a fiber opticcable. The function of the receiver is to select (filter) the desired signal, amplify and extract the information.
Interest arises in promoting communication within a building which is difficult and stressful going from one point to another within the building in the name of delivering information. In a domestic setting, family members will be collocated within the same building, but often will be unable to be heard using a normal speaking voice. Many households utilize intercom systems to facilitate conversations between remote parts of the home, but these systems have their drawbacks. They require one or both parties to go to specific parts of the house or hold onto a handset in order to communicate. They also offer little ability to direct communication to a person, within the house when the location of the person is initially unknown.
An intercom system is therefore a private telecommunication system that allows typically two or more locations to communicate with each other like telephone does. An intercommunication system may be a simple two- station system or a multi – station system. Many productions which need co-operation of more than a few people need special intercoms that cover many users. Intercom systems used in TV and stage productions are usually headsets type intercoms connected to one line using party line arrangement. The primary use of this type of system is in lives 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. A simple two station wired intercom system can be used as an intercom and door phone. One can use an intercom system from the house to house gate to screen visitors to the house.
Intercommunication systems are well known which allow residents of apartment buildings to communicate with callers waiting outside, and also to open the main door or gate. With these systems, the caller announces himself through an intercommunication apparatus having a keyboard for calling the individual apartments, which is arranged near the main gate, and the resident replies via an intercommunication apparatus in the apartment, including a door-opening pushbutton.
Since both the connections between the indoor and the outdoor intercommunication devices, as well as the electric supply to the outdoor device, require electric conductors extending to the area of the main gate, the installation of such conductors involves carrying out destructive operations such as wall-breaking, excavations, etc. in the building and/or in the surrounding court or garden. These operations are often inappropriate or unduly expensive, e.g. in the case of buildings surrounded by very wide or historically interesting parks or courts, whose integrity and original condition it is desirable to maintain.
In this project work, discussions will base on design and implementation of a two station intercom system that will result in the instrumentation of a home to facilitate flexible one and two-way audio conversations. The intercom circuit will consist of two intercom stations linked to each other with a push – to – talk (PTT) switch. This kind of circuit, generally consist of only one or two amplifiers and generally uses loudspeakers as normal speaker and microphones (how it is used depends on talk switch position). Depending on the circuit design, there could be one PTT switch on one end, or separate PTTs on both stations (as in this case).
1.2 AIM AND OBJECTIVE
The aim and objective of this project is to design and construct a simple intercom system (mainly two communication stations) as a means to replace man’s labour and stress of walking over a given premises for information delivery.
1.3 APPLICATION OF THE PROJECT
Intercom Systems is used in places like:
- Home,
- Office or
- Business
- Churches
- Vehicles – vehicles including trains, watercraft, aircraft and armored fighting vehicles.
1.4 TERMS AND DEFINITION
- Master Station or Base Station – These are units that can control the system, i.e., initiate a call with any of the stations and make announcements over the whole system.
- Sub-station – Units that are capable of only initiating a call with a Master Station but not capable of initiating calls with any other stations (sometimes called slave units).
- Door Station – Like sub-stations, these units are only capable of initiating a call to a Master Station. They are typically weather-proof.
- Intercom Station – Full-featured remote unit that is capable of initiating and receiving party-line conversation, individual conversation and signalling. May be rack-mounted, wall-mounted or portable.
- Wall Mount Station – fixed-position intercom station with built-in loudspeaker. May have flush-mounted microphone, hand-held push to talk microphone or telephone-style handset.
- Belt Pack – portable intercom station worn on the belt such as an interruptible feedback (IFB) with an earpiece worn by talent.
- Handset – permanent or portable telephone-style connection to an intercom station. Holds both an earpiece and a push to talk
- Headset – portable intercom connection from a belt pack to one or both ears via headphones with integrated microphone on a boom arm. Connects to a belt pack.
- Paging Signal – An audible and/or visual alert at an intercom station, indicating that someone at another station wants to initiate a conversation.
- Power Supply – Used to feed power to all units. Often incorporated into the design of the base station.
- Telephonic – Intercom systems that utilize a transmitter (talk) and receiver (listen) to communicate, similar to standard telephone systems.
- Amplified – Intercom systems that utilize a single speaker to transmit and receive communications.
- Amplifier – An intercom systems main or central component that is responsible for switching or connecting communication paths between master and substations in addition to distributing or switching power to auxiliary connected devices i.e. door strikes to allow entry.
1.5 PURPOSE OF THE PROJECT
The main purpose of the Intercom system is to provide voice communication between 2 or more locations.
1.6 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.
1.7 SIGNIFICANCE OF THE STUDY
These intercom system can be used as a door phone, connecting from the house to the door to screen visitors to your 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.
1.8 SCOPE OF THE STUDY
The scope of this project work is limited to the design, construction intercom device system with specification that;
i The demodulator should operate with a minimum distortion while producing an adequate output
- The small signal amplifier must provide an undistorted signal into the buffer amplifier to be able to drive a speaker of 8Q. Impedance.
iii. A 9 volt d.c power supply is to be design and employed to power the intercom for operation.
- The mater and the remote stations will be built individually.
- 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 an intercommunication device. In this chapter, the background, significance, objective limitation of the study were discussed.
Chapter two is on literature review of an intercommunication device. 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.
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