Design And Construction Of An LED Display With Audio Output (Welcome)

ABSTRACT

This work is on design, construction and working of a LED Display System. The project covered a fairly comprehensive study of a Dot Matrix Information Display. system made up of light emitting diodes (LEDs), in which one or more LEDs are modulated and encoded with audio information or messages, is disclosed. The system has a LED Display panel with an interface circuit to a computer, an audio signal transmitter, and a receiver. An executive program runs on the computer for the visual display control of characters, decorative pattern or messages on the display panel. The receiver combined with a speaker is located at a distance from the display panel. The receiver is designed to demodulate the optically transmitted audio information and broadcast the messages with the speaker.

The project has been carefully designed such that the Dot Matrix Information Display operates with electrical power from any source alternate or direct current. 

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• PROJECT MOTIVATION
• AIM OF THE PROJECT
• STATEMENT OF PROBLEM
• OBJECTIVES OF THE STUDY
• SIGNIFICANCE OF THE STUDY
• RESEARCH QUESTIONS
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• OVERVIEW OF THE STUDY
• ORIGIN/HISTORY OF THE PROJECT
• REVIEW OF DIGITAL SIGNALS
• PIXEL RESOLUTIONS
• CHARACTER RESOLUTIONS
• CHARACTER RESOLUTIONS

CHAPTER THREE

METHODOLOGY

• SYSTEM DISCRIPTION
• SYSTEM BLOCK DIAGRAM
• THE PROCESS OF DESIGN AND CONSTRUCTION
• LOADING THE ROM
• FABRICATION
• THE DISPLAY SYSTEM
• THE SOFTWARE
• MODE OF OPERATION
• POWER SUPPLY

CHAPTER FOUR

TEST AND RESULT ANALYSIS

• COMPONENTS ASSEMBLY
• CIRCUIT CONSTRUCTION TECHNIQUES
• SELECTION OF COMPONENTS
• STEP-BY-STEP-METHOD
• CONSTRUCTION ON VEROBOARD
• SOLDERING TECHNIQUES
• TESTING/COUPLING
• TIPS ON MAINTENANCE OF THE PROJECT

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION

CHAPTER ONE

• INTRODUCTION

1.1                                           BACKGROUND OF THE STUDY

Communication has become inevitable and vital thing in this present age, it is even believed to be a commodity meant for consumption by any targeted audience. One of the important qualities possessed by all animals is the ability to communicate with each other or one another at a given time.

An information display is a way of providing information and is used as an object for notification. It can be used for both indoor and outdoor which makes it universal fit for any form of alerts.

The extent of development in information dissemination has made it possible that the well known method of displaying information using sign posts, placards, notice boards, etc has to be modified by using intelligent display board.

In the previous years, the means by which adverts, information are display has been through the use of static mode of sign display such as banners, flyers etc, they are becoming boring and unattractive.

LED Display system display advertisements are designated to catch a people’s attention and create a memorable impression very quickly, leaving the reader thinking about the advertisement after they have driven past it. They have to be readable in a very short time because, they are usually read while being passed at high speeds.

This piece of digital technology can be found in a number of places and are being used for different purposes.

In some business places, it is used to display “welcome” which can communicate to customers when the business was opened.

This is a new generation of multicolor LED display system where, in addition to the usual function of LED display, they concurrently provide audio broadcasting through the visible light rays transmitted by the display panel or assembly. The  system is comprised of a tricolor dot matrix display panel with an interface circuit to a computer, an audio signal transmitter, and a receiver. It also comprises an executive program that runs on the computer for the display control of characters, decorative pattern or messages on the display panel. The receiver is designed to demodulate the optically transmitted audio information, and reproduce the messages with the speaker. For modulating emission of the LEDs, an oscillator is used to vary the frequency of on/off periods of the LEDs. The frequency of flicker is high enough to be indistinguishable by human eye and, hence, display appears to be constantly illuminated.

1.2                                          STATEMENT OF THE PROBLEM

Due to limitation of the sign board or local sign board which could not display clearly at night expect light shines on it, it is then necessary that electronic display system is employed to counter the limits of the local sign board. The information displayed on the local sign board is less attractive compared to the information displayed using dot matrix display system. Also, the existed LED display system only displayed the programmed information which will make it difficult for the blind to read the information displayed.

Thus, researchers are prompted to tirelessly hold up to these challenges by initiating some means of improving the above among which is the design and construction of a dot matrix display system with an audio output..

1.3                  AIM AND OBJECTIVES OF THE PROJECT

The main aim of this work is to build an LED display system that will display “WELCOME” with audio output. Specifically this study will achieve the following:

i        To display “welcome”

ii       To use the LED display system constructed as a sign post for the electrical department.

iii      To have more knowledge on what LED display system is all about.

v       To know the benefits of an LED display system.

1.4                                                      PROJECT MOTIVATION

The motivation of this project comes from the change involved with information in respect to time this days now prompt the huge step of constructing a reprogrammable intelligent display board to give information about anything at a particular moment to the targeted audience and need to know how Dot matrix display system can at least provide some improved measures to the limitations of conventional display listed in the problem statements. The astonishing and spectacular display of an electronic display is as well a source of inspiration.

1.5                                          SIGNIFICANCE OF THE STUDY

In all field of human endeavour, LED display system plays very vital role, such as means of advertisement, means of communication, presentations, exhibitions, identification and direction. It is also used in giving warning or safety instructions, such as warning signs, traffic signs, exit signs or signs conveying rules and regulations. This project write-up will be a guide to future designing in a related work.

1.6                                         JUSTIFICATION OF THE PROJECT

Due to the various problems encountered in the manual/analog design and construction of signposts for advertisement, there is every need for an automated electronic display system that will solve this problem. This will ensure that viewers get the adequate information that is displayed in good and attractive colors. The though the manual/analog way of displaying information to the view of the people is still targeted viewer are attracted. The height in which advertisement in Nigeria have attained will be maintained if some of its design/construction operation is computerized (Micro controller based information display) especially the one’s that has to do with bigger companies. This will also maintain the good relationship between the company and its numerous customers.

1.7                                               SCOPE OF THE STUDY

The scope of this study covers the building of an LED display system in which all the light-emitting diodes (LEDs) are modulated and encoded with audio information is presented. The novelty is on the concurrent use of the tricolor LED display for simultaneous visual message display and audio signal transmission in a free-space optical link. Program written in Assembly language was burned into the EPROM (Erasable Programmable Read Only Memory) of the system. The operation and working were enunciated. There are recommendations as the project is of outstanding quality. The feature of multiple colour makes it unique from other single colour display.

CHAPTER FIVE

5.1                                                               CONCLUSION

In conclusion, the LED display system was designed, constructed, tested satisfactorily and was found worthy of mass production. It was designed from inexpensive components. It has features that made it unique from other display boards in the market; the presence of multiple colour makes it preferable to other single colour display and the fact that it displays “welcome”.

This display system provides a visual signal and uses the visual light rays for transmitting audio messages to a remotely located target, is described. The display characters (WELCOME) in a decorative pattern can be conveniently implemented. Scrolling of the pattern on the LED display panel is allowed. During pattern updates, no noise is received at the receiver. The receiver needs to cover only one column in order to recover all information transmitted from the dot matrix display. A software program is used to control the LED display in each row and column of the display panel to display the desired pattern.

The LED dot matrix display described in this paper belongs to a new generation of dot matrix displays, as the visual light emitted from the display contains audio messages. It has long been realized that visible light has the potential to be modulated and used as a communication channel with high entropy. This application makes use of free space as a communication medium, and the receiver is required to be in LOS with the transmitter. It should be noted that the transmitter provides easy target for the line-of-sight reception by the receiver. This is because the LEDs, being on all times, are also indicators of the locations of the transmitter. This development can lead to many new applications in the industry. With diverse commercial and industrial applications, the experimental results in this paper have demonstrated that the proposed idea is totally feasible.

5.2                                                          RECOMMENDATION

This project is designed to be used in offices, shops, industries and also road sides, even at night to pass information to the public. And should be used and maintain by a qualified personnel.