Description
ABSTRACT
This work is on 500w wireless public address with lecture podium and solar system which is an electronic sound amplification and distribution system with a microphone, amplifier, podium stand, solar inverter and loudspeakers, which used to allow a person to address a large public such as in in lecture hall.
This wireless public addressing system have a potential for audio feedback, which occurs when sound from the speakers is picked up by the microphone, which converts the sound energy to electrical energy, the energy electrical signal being transmitted is been received and amplified by the amplifier circuit. The amplifier’s output is fed into the loudspeaker which converts the electrical energy back to the original form but amplified sound energy. This project is made up of the solar power supply unit, the pre-amplifier and power amplifier units, wireless unit and the tone control unit. This system is capable of delivering 500W of electrical power into a 8 ohm load(loudspeaker).
TABLE OF CONTENT
COVER PAGE
APPROVAL PAGE
DEDICATION
ACKNOWLEDGEMENT
TABLE OF CONTENT
CHAPTER ONE
- INTRODUCTION
- BACKGROUND OF THE PROJECT
- PROBLEM STATEMENT
- OBJECTIVE OF THE PROJECT
- SIGNIFICANCE OF THE STUDY
- APPLICATION OF THE PROJECT
- SCOPE OF THE PROJECT
- PROJECT JUSTIFICATION
- PROJECT WORK ORGANIZATION
CHAPTER TWO
LITERATURE REVIEW
2.1 REVIEW OF PUBLIC ADDRESSING SYSTEM
2.2 HISTORICAL BACKGROUND OF PUBLIC ADDRESSING SYSTEM
2.3 DIFFERENT TYPES PUBIC ADDRESSING SYSTEM
CHAPTER THREE
CONSTRUCTION
3.1 BASICS OF PUBLIC ADDRESSING SYSTEM
3.2 BLOCK DIAGRAM OF THE SYSTEM
3.3 COMPONENTS OF A TYPICAL SYSTEM
3.4 CIRCUIT DIAGRAM
3.5 THE WIRELESS MICROPHONE AND ITS RECEIVER
3.6 COMPONENTS PARTS
3.7 SOME IMPORTANT AUDIO TERMINOLOGY
CHAPTER FOUR
RESULT ANALYSIS
- CONSTRUCTION PROCEDURE AND TESTING ANALYSIS
- CASING AND PACKAGING
- ASSEMBLING OF SECTIONS
- TESTING OF SYSTEM OPERATION
CHAPTER FIVE
5.1 CONCLUSION
5.2 RECOMMENDATION
5.3 REFERENCES
CHAPTER ONE
- INTRODUCTION
A public address system allows you to broadcast information to a large group of people, whether you are giving a speech or playing live or recorded music.
Public address systems typically consist of input sources, pre-amplifiers, control and monitoring equipment, and loudspeakers. Input sources refer to the microphones that provide a sound input for the system. These input sources are fed into the pre-amplifiers. The pre-amplified signals are then passed into the audio power amplifiers.
These amplifiers will amplify the audio signals to an adequate speaker line level. In view of the above, one can now say that the public address system is an electronic amplification system used for communication in public areas.
Microphone is a device that converts sound waves into electrical waves. Sometimes colloquially called a micro mike is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, live and recorded audio engineering, in radio and television broadcasting and in computers for recording voice, and for non-acoustic purposes such as ultrasonic checking. The sensitive transducer element of a microphone is called its element. Since a wireless microphone is used in this project; a wireless microphone is one in which communication is not limited by a cable.
Solar inverter used ensures an uninterruptible power supply to the whole system by providing a renewable energy source (solar) using and inverter which is used to provide a 220vac to the whole system.
1.1 BACKGROUND OF THE PROJECT
A public address system comprises electrical equipment to greatly amplify a speaker’s voice so it will reach a much larger assemblage than he could speak to unaided. Beginning with the presidential conventions of the two major parties in 1920 and the inaugural address of President Harding in March 1921, when a special address system installed by the telephone engineers enabled him to address an audience estimated at 125,-000, there followed in rapid succession, many public events demonstrating the value of such systems. One of the most notable of these occurred on Armistice Day 1921, when the speeches, prayers and music at Arlington, Virginia, were heard, not only by 100,000 persons gathered there at the National Cemetery, but by some 35,000 in New York City and 20,000 in San Francisco. On this occasion the three public address systems, one for each of these cities, were joined by long distance telephone circuits.
The fundamental requirements of a satisfactory public address system are naturalness of reproduction and wide range of output volume. The meeting of these two requirements for music proves more difficult than for speech.
The public address system here described is most readily considered in three sections—“pick-up” apparatus which is placed in the neighborhood of the speaker and converts his words into undulatory electric currents; a vacuum tube amplifier for amplifying these currents; and a “receiver-projector” for reconverting the current into sound waves and distributing the sound over all of the audience. In the present system each of these three parts of the equipment has been designed with the intention of making it as nearly distortionless as possible, so that the various parts might be adaptable for audiences ranging in size from possibly one thousand to several hundred thousand, and might also be used in connection with the long distance telephone lines and with either radio broadcasting or receiving stations. One of the larger public address systems is easily capable of magnifying a speaker’s voice as many as 10,000 times.
The pick-up device whether of the carbon microphone variety or a condenser transmitter need not be placed close to the speaker’s lips but will operate satisfactorily when four or five feet away. The loud-speaking receiver mechanism is so designed that it will carry a power of several watts with small distortion. Under normal conditions, 500 watts distributed among a number of receiver-projectors arranged in a circle is ample to reach an audience of 700,000 persons.
1.2 PROBLEM STATEMENT
This project was carried out to overcome communication problems that usually occur when addressing a large audience such as making announcements or speeches so that everyone can listen precisely to what the speaker is talking about such as in a school. This simple project may also be used by lecturers in lecture halls to bridge communication gap between the lecturers and student in a lecture, as shouting during lectures may be very exhausting. This existed type of this device comes with conventional power supply which suffers power interruption whenever there is power outage. But this was also built to overcome this challenge by providing an uninterruptible power source using a renewable energy source to the system.
1.3 AIM AND OBJECTIVES OF THE PROJECT
This aim of this work is to build 500w wireless public address with lecture podium and solar system.
The objectives of the system are:
- To build a system prototype
- To provide adequate tone controls and mixer stages so as to enable communication or reproduction of speech and recorded music in buildings and institutions.
- To provide an uninterruptible power source to the system using a renewable energy source.
1.4 SIGNIFICANCE OF THE STUDY
Carrying out this work will serve as a means of becoming familiar with solar energy and its installation. This study will also help the reader to understand the working principle of a wireless Public addressing system.
1.5 APPLICATION OF THE PROJECT
Public addressing system is often used in small venues such as school auditoriums, churches, and small bars. PA systems with many speakers are widely used to make announcements in public, institutional and commercial buildings and locations.
1.6 SCOPE OF THE PROJECT
The scope of this work covers building a500w wireless public address with lecture podium and solar system.
1.7 PROJECT JUSTIFICATION
Over the ages, science and technology has been developing with new inventions in various fields; including the increase in modifications on existing technology all gearing towards improving effectiveness and reliability of equipment and achieving to a great degree miniaturization and optimal cost.
This project is backed by my interest in the area of electronics and communication, and having been groomed to a great extent with introductions into the various fields of electrical and electronics engineering, with the knowledge in principles of telecommunications, telecommunication engineering.
CHAPTER FIVE
5.1 CONCLUSION
Wireless Public address systems are an essential tool in communication throughout a premises or campus. The construction of this system would open up new simple and innovative way of delivery audio sounds from auditoriums. The system’s simplicity would require less technical ability in terms of operating the sound system while delivering a speed of lecture from the same location. This makes it user friendly and an essential part of everyday life of sound production and delivery of sound in auditoriums. This would further create job for many engineers when the design is finally adopted. The system would serve as a voice reinforcement in Conference and Meeting Rooms, Auditoriums, Churches, Hotels, Motels, Schools, Clubs, Meeting Halls, etc.
5.2 RECOMMENDATION
The system is highly recommended for auditoriums to ensure that one’s message is heard loud and clear. It would largely go a long way to create space as it eliminates the use of un-powered lecterns and public address at the same time in an auditorium. The compact nature of the system saves time and the hassle of mounting public address system with limited time.
Finally it is recommended for both indoor and outdoor programs provided it is not exposed to environmental factors like extreme heat and rain.
