DESIGN AND CONSTRUCTION OF A VARIABLE A.C. VOLTAGE SOURCE WITH DIGITAL DISPLAY

1.1 Introduction

The development of information display electronic based system has covered numerous technologies since its beginnings (Gowrishankar, Mritha, & Chandra, 2014). Digital Display, is a system electronically designed and constructed, that is used to display different information to the view of the masses. The information to be displayed could be diagrams, symbols letters, colours, numbers, codes etc depending on what is needed at a particular places and time. This without doubt, has made life easier for the people in different ways, however electronics display board, which is the heart of this system, can be described thus: an electronic display is a computer. All computers whether we are talking personal desktop computer you are using is a general-purpose computer than can run any of thousands of programs.

As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Limitations of the Study and Definition of technical terms.

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1.2 Background of Study

Display technologies have been developed for many years. In the late twentieth century, cathode Ray Tube (CRT) dominated the market. However, new trends in display include the demand of picture quality, size and power consumption. So, Liquid Crystal Display (LCD) is then emerging to be the current market. Due to their relatively light weight, low operating power and compact design, LCD has become a popular part of home entertainment system and it continues to dominate the existing market (Chan, Cheungkaki, & Mak, 2011). Traditional LCD requires colour filter to display full color. Electronic display devices nowadays are mostly controlled by a microcontroller. And the semiconductor that gives out light like an LED has been a great breakthrough in electronic display (Baron, 2011). Field Sequential Color of LCD (FSC-LCD) generates full color without color filters, with the use of colour addition.

The electronic digital display system as used in this report refers to a sign that uses electronic hardware and software to display its copy, messages or images. Also, a sign utilizing a fixed light source to provide a message in text, images pictures, and/or symbols that may appear to move or may appear as on/off messages. This is in contrast to traditional non-electronic signs where the copy displayed is physically applied to the sign surface by printing, painting or otherwise attaching it onto the sign. The materials or substrate to which the copy is applied is typically paper, wood, plastic or the wall of a building.

In this modern time, solid materials have helped man to show that he exists by doing wonders in the world of electronics. One major development, made possible by the enormous advances in solid-state technology, is the “digital revolution”. Circuits are designed to implement the basic digital logic functions fundamental to all digital systems. Digital electronics, therefore, comprises the design, manufacture and use of circuits for processing information in digital form (Simpson, 1978).

Digital Display project uses LEDs in displaying streams of characters by putting ON and putting OFF these LEDs consistently and in a very fast manner that one could hardly notice the effect of this LEDs coming ON and going OFF. It consists of a small PC board containing LEDs arranged in a matrix of 5 by 7 i.e. 5columns and 7rows making up of 35 LEDs in each page. The PC board also contains an AT89S52 microcontroller. It uses this Microcontroller in controlling the ON and OFF sequence of the LED. It can also be programmed to use some scrolling effects like jumping, blinking, dropping e.t.c. when displaying the characters as programmed in the microcontroller. The hardware is grouped into two; electrical circuit and the screen (containing the LEDs). The electrical circuit is also grouped into the power circuit and the display control circuit, in the display control circuit, we have diodes, transistors, capacitors, regulator, crystal and buffers. A capacitor and resistor near the chip creates the R-C timing for the oscillator (the chip contains the rest of the components for the oscillator).

The extent of development in information dissemination has made it possible that the well-known method of displaying information using signposts, notice boards, etc has to be modified by using an electronic digital display system. In today’s rapidly advancing technology market, most conventional digital display systems are not being implemented using individual logic gates and integrated circuits (ICs) such have been used in the past instead, programmable devices such as microprocessor and microcontroller chips which contain the circuitry necessary to create logic functions are being used to implement digital systems. The use of a 555 timer as a stable multi-vibrator and decade counter (CD4017) can be used to build a less expensive electronic display system. The use of these two major ICs will bring about less board space, fewer power consumptions and overall, low cost in manufacturing.

This project, however; emphasizes mainly the display of information using two major integrated circuits (ICs) namely NE555 timer (ICI) and CD4017 (IC2) to control the lighting of LEDs. This message display circuit is built around readily available, low-cost components. It is easy to fabricate. A total of 250 LEDs will be used to display the message “WELCOME TO NOUN ADO EKITI STUDY CENTRE”.

Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Design and Construction of a Variable A.C. Voltage Source with Digital Display.

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1.3 Statement of the Problem

Due to the various problems encountered in the manual design and construction of a Variable A.C. Voltage Source with Digital Display, there is every need for an automated electronics display system that will solve this problem. This will ensure that viewers get the adequate information that is displayed in good and attractive colors. Though the display board, a way of displaying information to the view of the people is still targeted, viewers are attracted.

The height is which advertisement in Nigeria will be maintained if some of its design, construction operation is computerized (electronics display board) especially the ones that has to do with bigger companies. This will also maintain the good relationship between the company and its numerous customers. 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 an electronic digital display system.

The limitation of the signboard or local signboard which could not display clearly at night except light shines on it, it is then necessary that an electronic display system is employed to counter the limits of the local signboard. The information displayed on the local signboard is less attractive compared to the information displayed using an electronic digital display system.

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1.4 Aim and Objectives of the Study

The aim of the study is to Design and Construct a Variable A.C. Voltage Source with Digital Display. In achieving this aim, the following specific objectives were laid out as follows:

1. To design a system that will display “Great Nigerian students”
2. To construct a Variable A.C. Voltage Source with Digital Display system that will use the electronic digital display system constructed as a signpost for Federal Polytechnic, Nekede.
3. To provide the required power to the load using an AC supply at the input.
4. To design a power supply with one output terminal with variable output voltage, and the output is gotten by turning the voltage adjuster known as the potentiometer.
5. To construct a system that will display a moveable coded letters that welcomes a visitor to the department this displays WELCOME TO NOUN ADO EKITI STUDY CENTRE.

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1.5 Significance of the Study

Electronic digital display system plays a 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 study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.

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1.6 Scope of Study

The study focuses on the Design and Construction an Electronic Digital Display Board that will display a moveable coded letters that welcomes a visitor to the department this displays WELCOME TO NOUN ADO EKITI STUDY CENTRE.

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1.7 Limitations of the Study

During the course of this study, many things militated against its completion, some of which are:

1. Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
2. Research material: availability of research material is a major setback to the scope of the study.
3. Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
4. Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).