CONSTRUCTION OF A MICROCONTROLLER BASED T-JUNCTION TRAFFIC LIGHT CONTROLLER

ABSTRACT T-junction traffic light controller is such a device that will play a significant role in controlling traffic at junctions, to ease the expected increased rush at such junctions and reduce to minimum disorderliness that may arise, as well as allowing the pedestrians a right of the way at intervals rather than being struck down when in a hurry to cross the roads. Such an electrical system with a touch of electronics that control the flow of traffic in a pre-determined sequential pattern at a junction, has its diagram comprising of different components. The power supply unit provides the control unit with specified voltage from primary source. The pulse generator consisting of a timer generates pulse for the system. The clock or counter moderates the signal that enters the decoding logic system. The display unit of each stand consists of led, the first is red in colour, the second is amber in colour and the last is green in color.
TABLE OF CONTENTS     Title Page - - - - - - - - - - - -i Certification - - - - - - - - - - -ii Dedication - - - - - - - - - - - -iii Acknowledgement - - - - - - - - - -iv Abstract - - - - - - - - - - - -v Table of Contents - - - - - - - - - -vi List of Figures - - - - - - - - - - -x

CHAPTER ONE INTRODUCTION 1.1 Background of the Study - - - - - - - -1 1.2 Objective of the Project - - - - - - - - -3 1.3 Scope of the Study - - - - - - - - -3 1.4 Project Report Organization - - - - - - - -3
CHAPTER TWO LITERATURE REVIEW 2.1 Introduction - - - - - - - - - -5 2.2 Pre-Emption And Priority - - - - - - - -8 2.3 Special Provisions - - - - - - - - -10 2.4 Technology- - - - - - - - - - -11 2.5 Control And Co-Ordination- - - - - - - -14 2.6 Design Layout And Operation Site- - - - - - -14
CHAPTER THREE DESCRIPTION OF SYSTEMS 3.1 The Power Supply - - - - - - - - -15 3.2 The Voltage Regulator - - - - - - - - -16 3.3 Crystal Oscillator - - - - - - - - - -21 3.4 Paper Capacitor-   - - - - - - - - -26 3.5 The Microcontroller- - - - - - - - -27 3.6 System Flow Diagram- - - - - - - - -33 3.7 Light Indicator Stage- - - - - - - - -35 3.8 Transistors- - - - - - - - - - -35 3.9 Resistors-   - - - - - - - - - -41 3.10 Bridge Rectifier- - - - - - - - - -44 3.11 Electrolytic Capacitor- - - - - - - - -45 3.12 Step Down Transformer- - - - - - - -48 3.13 Seven Segment Display- - - - - - - - -49
CHAPTER FOUR SYSTEMS OPERATIONAL UNITS 4.1 The Control Unit - - - - - - - - - -55 4.2 System Analysis - - - - - - - - -56 4.3 Choice Of Counter - - - - - - - - -56 4.4 The Interface Unit- - - - - - - - -57 4.5 Test And Result - - - - - - - - - -58 4.6 Observation - - - - - - - - - -58 4.7 Packaging-  - - - - - - - - - -59 4.8 Bill Of Engineering Measurement And Evaluation - - - -60
CHAPTER FIVE CONCLUSION AND RECOMMENDATIONS 5.1 Conclusion -- - - - - - - - - -63 5.2 Recommendations- - - - - - - - -63 5.3 Suggestions For Further Research- - - - - - -64  References- - - - - - - - - - -65
LIST OF FIGURES Figure 1.1 Traffic light control system Figure 3.1 Regulated power supply Figure 3.5 The AT89C51 microcontroller circuit Figure 3.6 System flow diagram Figure 3.81 Transistor as a switch Figure 3.10 The bridge rectifier Figure 3.13 The individual segments of a seven   segment display Figure 3.14 General circuit diagram Figure 4.1 Block diagram of a control circuit Figure 4.7 Project package photograph
INTRODUCTION  The traffic on our roads, especially intra-city traffic due to increasing number of cars grow by the day and unless adequate steps are taken to control the situation, we shall soon meet with circumstances we do not bargain for. That the innumerable traffic junctions in the country by far out-number the staff strength of the traffic wardens available and that the traffic wardens even where they are enough to control all the junctions cannot do so throughout the day is not in doubt. Traffic control at T.junctions or elsewhere ensures orderliness of movements of vehicles, goods and pedestrians while its absence strongly indicates chaos and most at times leads to accidents.
In the light of the above, it is imperative to recognize the need to compliment the physical exhausting efforts of the traffic wardens. In doing so, steps to be taken should assume permanence in nature rather than any ad-hoc exercise. Such is the role expected to be played by an installed operational road junction traffic controller. This project –DESIGN AND CONSTRUCTION OF A THREE WAY JUNCTION TRAFFIC LIGHT CONTROLLER is such a device that will play significant role in controlling traffic at junctions to ease the expected increased rush at such junctions and reduce to minimum such disorderliness that may arise as well as allowing the pedestrians a right of the way at intervals rather than being struck down when in a hurry to cross the roads.
Such an electrical system with a touch of electronics that controls the flow of traffic in a pre-determine sequential pattern at a junction has its diagram below with blocks representing distinct units.