ABSTRACT
The aim of this project work is to design and construct an electronic digital display system, based on light-emitting diodes connected in an array that forms the information to be displayed i.e. “GREAT NIGERIAN STUDENTS”. This project is useful for creating attention – getting messages, presentations, advertisements and location identifiers. The system consists of power supply unit, oscillator unit, counter unit, driver unit and output unit. The power supply unit uses alternating current (AC) from the mains which will be stepped down to 12V using a step-down transformer, rectified with bridge rectifier, filtered with the actual capacitor and regulated to 9 volt using an IC regulator. The oscillator unit contains a 555 timer IC set as astable multivibrator used to produce clock pulses for the counter unit which contains 4017 decade counter IC. The 4017 counter enables the information to be displayed sequentially as desired. The driver unit uses transistor to amplify the signal strength of the counter’s output. The output unit enables the information to be displayed using light emitting diodes (LEDs).
CHAPTER ONE
INTRODUCTION
1.1 Background of the study
Electronic digital display system as used in this reports 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 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 really 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).
An information display is a way of providing information and it is also used as an object for promotion. It can be seen in a form of cardboard or tarpaulin at stores / shops, sign posts, placards, notice boards and electronic display boards. But the advent of new technologies has made the information in the form of an electronic display in the world of advertisements and promotions (Gupta, Shukla and Nagwekar, 2013). The ability to display a short message can be useful application to be available for any business. Electronic digital display system is perfect for this application. It can be used for both indoor and outdoor which makes it universal fit for any business or event. Electronic digital display system is very efficient and cost effective way to spread messages to thousands of people, without any personal contact or door to door sales. Light-Emitting Diode (LED) is a solid state light source with several attractive properties for display application. LED is a diode that gives off visible light when forward biased (Mehta and Mehta, 2014). It is chosen as the main component for displaying messages because, today LED is the most energy efficiency example and other useful systems.
