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GHANA TECHNOLOGY UNIVERSITY COLLEGE

FACULTY OF ENGINEERING

DEPARTMENT OF TELECOMMUNICATIONS ENGINEERING

TITLE:

AN INTELLIGENT TRAFFIC SIGNALLING SYSTEM FOR

SELECTED ROAD INTERSECTIONS IN KUMASI

A Project Work Submitted in Partial Fulfilment of the Requirements for

BSc. In Telecommunications Engineering

BY:

KONADU YIADOM KWASI (B010113504)

SUPERVISOR:

MR FRANCIS KWABENA ODURO – GYIMAH

JUNE 2016

II

DECLARATION

This project is presented as part of the requirements for Bsc. in Telecommunications

Engineering awarded by Ghana Technology University College. I hereby declare that this

project is entirely the result of hard work, research and enquires. I am confident that this

project work is not copied from any other person. All sources of information have however

been acknowledged with due respect.

AUTOR:

Konadu Yiadom Kwasi DATE: ……………………………

STUDENT ID: B010113504 SIGNATURE: ……………………

SUPERVISOR:

Mr. Francis Kwabena Oduro - Gyimah DATE: …………………………

SIGNATURE: …………………….

HEAD OF DEPARTMENT:

Mr. Francis Kwabena Oduro - Gyimah DATE: ……………………………

SIGNATURE: …………………….

III

ACKNOWLEDGEMENT

First and foremost my utmost appreciation goes to God Almighty for His protection and

favour upon my life throughout my studies. I owe Him every success and achievement in this

project.

I express my profound gratitude to my supervisor Mr Francis K. Oduro – Gyimah for his

encouragement, direction and guidance throughout this project. His forward thinking and

dedicated mentoring have been an invaluable source of inspiration in this project.

Much appreciation goes to Mr Ngala whose lucid explanations on traffic variation on roads

were a great help in my research into intelligent traffic light systems. His readiness response

to my enquiries were also much appreciated.

I am deeply grateful to Mr Kusi Ankrah of Sunyani Polytechnic, who was incredibly

welcoming and forthcoming in providing assistance when contacted.

My sincere gratitude goes to Kodom, who gave me my first Proteus ISIS 7 tutorial and thus

opened up to me the immense potential of the software.

To all my course mates, I am eternally grateful for the constantly willing input and

contributions to problems pertaining to this project.

Finally to my friends and family I am highly indebted to you all for your support both

physically and spiritually. I say God bless you all.

IV

LIST OF ABBREVIATIONS

AC: Alternating Current

ADC/DAC: Analog to Digital Converters / Digital to Analog Converters

CAN: Controller Area Network

CPU: Central Processing Unit

DC: Direct Current

DIP: Dual In-line Package

EEPROM: Electrically Erasable Programmable Read-only Memory

FTTLC: Fixed Time Traffic Light Controllers

GPS: Global Positioning System

GSM: Global System for Mobile Communication

IR: Infrared

IVS: Intelligent Video Sensor

LED: Light Emitting Diodes

LCD: Liquid Crystal Display

MCLR: Master Clear

MAC: Medium Access Control

NEMA: National Electrical Manufacturers Association

OSC1/CLK IN: Oscillator Crystal Input

V

OSC2/CLKOUT: Oscillator Crystal Output

PLC: Programmable Logic Controller

PIC: Peripheral Interface Controller

PWM: Pulse Width Modulation

RAM: Random Access Memory

ROM: Read only Memory

RFID: Radio Frequency Identification

RSU: Road Side Unit

RF: Radio Frequency

SPI: Serial Peripheral Interface

TX/RX: Transmitter/Receiver

UART: Universal Asynchronous Receiver/ Transmitter

VIP: Video Image Processors

VSS and VDD: Voltage supply

VSM: Virtual System Modelling

WPAN: Wireless Personal Area Network

VI

ABSTRACT

Vehicular traffic is increasing tremendously in Ghana, especially in the cities which is

contributing huge negative impact on transportation in the country. Traffic in the cities is

mainly regularized by traffic lights, which may contribute to the unnecessary long waiting

times for vehicles if not efficiently configured. This inefficient configuration is unfortunately

the case for the traffic lights on the Tech to Adum road in Kumasi. The traffic lights situated

at the Bomso, Anloga and Amakom intersections are based on fixed time cycle protocol

hence cannot better accommodate the increasing traffic variations that occur at different times

on the road. Moreover, emergency vehicles such as ambulance and fire trucks sometimes get

delayed at the intersections since the traffic lights lack the intelligence to detect such vehicles

and provide access for them. Therefore, this study proposes a traffic signalling system that

can work on real time basis to help optimize congestion and wastage of time at the

intersections. The proposed system provides automatic switching of the traffic light based on

traffic density, remote override feature for emergency vehicles on priority basis and

monitoring and detection of system breakdown or malfunctioning of the LED lights. During

normal time the signal timing changes automatically on sensing the traffic density at the

junction but in the event of any emergency vehicle like ambulance, fire trucks etc. requiring

priority are built in with RF remote control to override the set timing by providing

instantaneous green signal in the desired direction while blocking the other lanes by red

signal for some time. However in the advent of malfunctioning of the LED lights, the

controller reports “fault” to the main traffic control room to the maintenance team via the RF

device. The system was designed and simulated using Proteus ISIS 7 software together with

MikroC programming language.

VII

TABLE OF CONTENTS

Contents

DECLARATION..................................................................................................................... II

ACKNOWLEDGEMENT ..................................................................................................... III

LIST OF ABBREVIATIONS ............................................................................................... IV

ABSTRACT ............................................................................................................................ VI

TABLE OF CONTENTS .................................................................................................... VII

LIST OF FIGURES ............................................................................................................... XI

LIST OF TABLES ............................................................................................................... XII

CHAPTER ONE ...................................................................................................................... 1

1.1 Introduction ..................................................................................................................... 1

1.2 Background study ........................................................................................................... 2

1.2.1 Overview of traffic flow in Kumasi ................................................................................ 3

1.2.2 Bomso Road intersection ................................................................................................ 5

1.2.3 Anloga Intersection ......................................................................................................... 6

1.2.4 Amakom intersection ...................................................................................................... 7

1.3 Problem Statement .......................................................................................................... 7

1.4 Objective ......................................................................................................................... 8

1.4.1 Main objective ................................................................................................................ 8

1.4.2 Specific Objectives ......................................................................................................... 8

1.5 Significance of the project .............................................................................................. 9

1.6 Scope of the Project ........................................................................................................ 9

VIII

1.7 Organisation of Study ................................................................................................... 10

CHAPTER TWO ................................................................................................................... 11

LITERATURE REVIEW ..................................................................................................... 11

2.1 Introduction ................................................................................................................... 11

2.2 The Traffic Light........................................................................................................... 11

2.2.1 First Four Way Traffic Signal ....................................................................................... 11

2.2.2 Light Emitting Diodes (LEDs) traffic light .................................................................. 12

2.3 The Controller Unit ....................................................................................................... 13

2.3.1 Electromechanical Controller ....................................................................................... 13

2.3.2 Peripheral Interface Controller (PIC Microcontroller) ................................................. 14

2.4 Sensors .......................................................................................................................... 15

2.4.1 Video/image sensors ..................................................................................................... 15

2.4.2 Inductive loop detector ................................................................................................. 16

2.4.3 Infra-red sensors............................................................................................................ 17

2.5 Strategies in Traffic Control ......................................................................................... 18

2.5.1 Fixed or Pre-timed Signal ............................................................................................. 18

2.5.2 Real Time Signal........................................................................................................... 19

2.6 Related works................................................................................................................ 19

CHAPTER THREE ............................................................................................................... 23

DESIGN METHODOLOGY ................................................................................................ 23

3.1 Introduction ................................................................................................................... 23

IX

3.2 Design of the ITSS ........................................................................................................ 23

3.2.1 Main Traffic Control Unit ............................................................................................. 24

3.2.2 The Emergency System Unit ........................................................................................ 25

3.2.3 The Monitoring Control Unit ........................................................................................ 26

3.3 Hardware Components Description .............................................................................. 27

3.3.1 Power Supply ................................................................................................................ 27

3.3.2 PIC 16F877A Microcontroller ...................................................................................... 28

3.3.3 The Radio Frequency (RF) Module .............................................................................. 32

3.3.4 Liquid crystal display (LCD) ........................................................................................ 34

3.3.5 Global Positioning System (GPS) ................................................................................. 35

3.3.6 Buzzer ........................................................................................................................... 36

3.3.7 Infrared Transmitter ...................................................................................................... 37

3.3.8 Infrared Receiver .......................................................................................................... 38

3.4 Software Developing tools (description) ...................................................................... 39

3.4.1 Proteus ISIS 7 ............................................................................................................... 39

3.4.2 MikroC .......................................................................................................................... 40

3.4.3 Flow chart for the ITSS................................................................................................. 41

CHAPTER FOUR .................................................................................................................. 42

ANALYSIS AND RESULTS ................................................................................................ 42

4.1 Implementation of the Intelligent Traffic Signalling System (ITSS) ........................... 42

4.2 Results for high density at lane two (L2) ...................................................................... 43

X

4.3 Results for emergency override .................................................................................... 44

4.4 Results for system failure of the LED traffic light ....................................................... 45

4.5 Results for malfunctioning of a particular LED traffic light ........................................ 46

CHAPTER FIVE ................................................................................................................... 47

Conclusion and Recommendations ...................................................................................... 47

5.1 Conclusion .................................................................................................................... 47

5.2 Recommendations ......................................................................................................... 47

References ............................................................................................................................... 49

Appendix ................................................................................................................................................

XI

LIST OF FIGURES

Figure 1. 1 Map showing Location of Road Intersections ................................................................ 4

Figure 1. 2 Layout of Bomso Intersection ........................................................................................ 6

Figure 1. 3 Layout of Anloga Road Intersection .............................................................................. 6

Figure 2. 1 First Four Way Traffic Signal ....................................................................................... 11

Figure 2. 3 A PIC16F877A Microcontroller ................................................................................... 14

Figure 2. 4 Traffic Signal Control using Inductive Loop Detector ................................................. 16

Figure 2. 5 Traffic Control using IR Sensors .................................................................................. 17

Figure 3. 2 Block Diagram of Main Traffic Control Unit ............................................................... 24

Figure 3. 3 Block Diagram of Emergency System Unit .................................................................. 25

Figure 3. 4 Block Diagram of Monitoring Control Unit ................................................................. 26

Figure 3. 5 circuit diagram of the power supply.............................................................................. 28

Figure 3. 6 Pin Diagram of the PIC 16F877A ................................................................................. 31

Table 3. 1 pin description of the PIC circuit .................................................................................. 32

Figure 3. 7 pin diagram of RF transmitter and receiver ................................................................. 33

Figure 3. 8 Pin Diagram of 20×4 LCD Display .............................................................................. 35

Figure 3. 9 GPS Module ................................................................................................................. 36

Figure 3. 10 schematic diagram of 5v buzzer module ....................................................................... 37

Figure 3. 11 circuit diagram of IR Transmitter ................................................................................. 37

Figure 3.12 circuit diagram of IR receiver ....................................................................................... 38

Figure 3. 13 Proteus ISIS 7 development environment ..................................................................... 40

Figure 4. 1 schematic diagram of the ITSS ..................................................................................... 42

Figure 4. 2 traffic light at lane two switched to green light for 6000ms ......................................... 43

Figure 4. 3 simulation of the emergency override ........................................................................... 44

Figure 4. 4 results for system failure of the LED traffic light ......................................................... 45

Figure 4. 5 shows simulation results for malfunctioning of a particular LED traffic light ............. 46

XII

LIST OF TABLES

Table 3. 2 Pin description of RF transmitter ....................................................................... 33

Table 3. 3 Pin description of RF receiver ........................................................................... 33

Table 3. 4 Pin description of 20×4 LCD display ................................................................ 34

CHAPTER ONE

1.1 Introduction

Mobility as one of the essential activities of life can be said to be inevitable in the lives of

living things (William, 2015). In human life, people migrate from one place to another by air,

water or road. From the Stone Age, movement of people and goods was through the use of

chariots and some animals such as donkeys, horses etc. Today, science and technology has

improved transportation with the introduction of vehicles, aeroplanes and other systems to

ease movement. Among the various modes of transportation, Road transportation has become

the predominant way for transporting goods and people from one point to another (Arasan,

2012). However with the rapid growth of population of the people in the world, there is an

upsurge in the number of vehicles and traffic demand on our road. This has resulted to issues

of traffic congestion, air pollution, sound pollution, weariness and time and energy wastage,

consequently the need for the practice of minimising road traffic congestion gaining more

popularity as the importance becomes apparent (Bagheri et al., 2007; Madhavi and Banga,

2012).

Moreover with the improvement of technology, several studies and findings are being worked

up to optimize and eradicate completely these prevailing problems that motorists and

pedestrians encounter and also enhance the road network system to facilitate economic

growth and reduce environmental hazards (Arasan, 2012). Efforts have been made to improve

the traffic flow which includes broadening of the roads around an intersection, prohibition of

turning movements at a junction, introduction of traffic circles at the road intersection and

traffic light. Among these, traffic light is doubtlessly the most familiar, important and

effective method of traffic control at intersections. They are generally installed to ensure

safety, decrease the average time of proceeding and increase flow of vehicles across the

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intersection. All these systems and measures are put in place based on certain data or

information collected over time. However, since the traffic situation at the cities varies over

time, the whole system has to be re-planned again because the road may have exceeded its

designed carrying capacity (Baffour, 2011). Hence, this study proposes a traffic signalling

system that can work on real time basis to help optimize congestion and wastage of time at

the intersections.

1.2 Background study

Traffic congestion is a serious problem encountered by many metro cities around the world.

Getting stuck within a dense traffic is a headache for every motorist and even traffic wardens

in controlling the traffic. According to David (2014), anyone who has ever driven a city street

and been frustrated by having to stop again and again for red lights has probably thought that

there must be a better way.

One of the oldest methods of controlling traffic was having a policeman positioned at each

junction and physically controlling the influx of traffic via hand signalling. However this was

quite arduous and complicated and then came the need for a different type of control using

traffic signals. Traditional traffic light controllers used fixed pre-set time for traffic influx for

each route at the junction. The controller was an electromechanical controller system

consisting of a dial timer, a solenoid and a cam assembly (Tarun, 2013).

However the whole concept of a fixed time traffic light controller (FTTLC) is not convenient

for cities where traffic flow is variable. Traffic load is highly dependent on parameters such

as time, day, season, weather and unpredictable situations such as accidents, special events or

construction activities. If these parameters are not taken into account, the traffic control

system will create bottlenecks and delays. A traffic control system that solves these problems

by continuously sensing and monitoring traffic conditions and adjusting the timing of traffic

3

lights according to the actual traffic load is called an intelligent traffic control system

(Muhammad, 2011).

1.2.1 Overview of traffic flow in Kumasi

Traffic flow is simply defined in the McGraw-Hill Dictionary as the number of vehicles

passing a given point in a given time. Traffic flow is expressed as vehicles per hour. Kumasi

is the second largest city and almost the hub of urbanized and densely inhabited Ghana. Road

transportation has been dominant in Kumasi, since air and rail transport just account for less

than one per cent of the daily movements of goods and persons within the Metropolis. The

road network is radial with Kejetia and Adum being the hub of the network. There are four

major arterial primary roads connecting Kumasi to other parts of the country consisting of the

Accra Road, the Tamale Road, the Sunyani Road, and the cape Coast Road. The inner and the

arterial roads have traffic lights and roundabout to regulate the flow of vehicle. Figure 1.1

shows the map of Kumasi with Selected intersections indicated in a rectangular box and

labelled accordingly which are located on Tech to Adum road (Kumasi Metropolitan

Assembly, 2015).

4

Figure 1. 1 Map showing Location of Road Intersections (Source: Obiri-Yeboah et al., 2013)

This study focuses on the problems associated with the traffic lights situated at the three

selected intersections highlighted on the map above; which include the Amakom intersection,

Anloga intersection and the Bomso intersection.

The traffic light was introduced at the intersections to control traffic congestion, ease the

stress of road users and reduce the time delay experienced by motorists at the intersections.

Unfortunately the system operates on fixed cycle time which does not consider the waiting

time on signals of different intersections. It controls vehicular movement and pedestrian

crossing based on certain time intervals that changes the lights accordingly whether there is

traffic or no traffic at the junctions (Syed et al., 2007).

Emergency vehicles such as police cars, fire trucks and ambulances are generally permitted to

cross an intersection against a traffic signal. These vehicles normally use horns, sirens and

flashing lights to prompt other motorists moving toward the intersection that an emergency

vehicle intends to cross that intersection. However, some motorists play adamant to the

warning signals issued by these emergency vehicles especially in a situation where the traffic

5

light gives way for traffic to flow across the intersection from a different direction. This

results in more delay of the emergency vehicle (Sahar et al., 2012).

There is no monitoring system to check the status of the traffic light and so in the case of

system failure or malfunctioning, vehicles get stacked in the traffic and the whole place get

jammed. Most at times the traffic at the intersections is controlled manually by a policeman

due to frequent system failure. In view of this, the FTTLC installed at these intersections on

the Tech to Adum road lacks the intelligence to identify the road with the higher density of

vehicles and also give special access to emergency vehicles such as Ambulance, Fire trucks

etc. As such it has worsened the traffic problems faced by road users and has failed to deal

with the congestions that occurs at different traffic situations (Syed et al., 2007). A general

observation of the traffic systems in Ghana was made by Baffour (2011). He recommended

that there is the need to refit the whole timing process to maximize the usefulness of the

traffic control devices to better serve the driving public.

1.2.2 Bomso Road intersection

The intersection at Bomso is signalised and is a few meters away from tech junction. The

intersection has four main lanes and two minor lanes .The main lanes consist of two lanes

approaching Tech from Adum and the other two lanes exiting Tech to Adum with one

approach and exit lanes connecting to the two minor lanes on the Bomso to Ayiggya road.

6

Figure 1. 2 Layout of Bomso Intersection (Source: Obiri-Yeboah et al., 2013)

1.2.3 Anloga Intersection

The intersection at Anloga consists of many configurations. Considering the Asokwa to

Aboabo road, it has four major lanes consisting of two entries and two exit lanes with two

minor lanes that connect to the Adum to Tech road. The Adum to Tech road also has the

same configuration with two minor lanes connecting to the Asokwa to Aboabo road.

Figure 1. 3 Layout of Anloga Road Intersection (Source: Obiri-Yeboah et al., 2013)

7

1.2.4 Amakom intersection

The Amakom signalised intersection has four lanes consisting of two approaches and two

exits on the Tech to Adum road. The Adum road has a short lane that branches to the stadium

road whiles the tech road also has a short lane that branches to the Asawase road. The

Asawase to stadium road has two lanes connecting the two towns. Each exiting lane has a

short branch road that connects to the Adum to Tech road. The figure below shows the road

configuration at the Amakom intersection.

Figure 1. 4 Layout of Amakom Signalised Intersection (Source: Obiri-Yeboah et al., 2013)

1.3 Problem Statement

Traffic control has become a major problem in Ghana especially in Kumasi. Traffic situation

at the Tech to Adum road is becoming overwhelming and inharmonious since the traffic

controllers situated at the intersections on the road are operated by fixed time controllers.

The fixed time traffic controllers (FTTLC) are programmed in a particular time interval to

control the flow of traffic at different directions with fixed time delay following a particular

cycle. In this study, it was observed that the traffic situation at the intersections varies

randomly at different periods within a day such that at a particular period, one side of the

intersection becomes denser when compared to the other. But since the controller is

8

programmed with a particular fixed time interval, regardless of the traffic changes that

occurs, it fails to efficiently control the variation of the traffic situation which consequently

leads to congestion especially during hours of heavy traffic, resulting in more unwanted time

delays.

Emergency vehicles such as ambulances, fire trucks etc. generally depend on horns, sirens

and flashing lights to alert other vehicles approaching the intersections. In situations where

the traffic light switches green light to clear the traffic from a different lane across the

intersection, the emergency vehicles are delayed for a while, which cause noise pollution and

threat to life and properties.

In the case of system failure or malfunctioning of the traffic light, it takes a longer time

before being fixed or serviced by the traffic control unit. This also creates huge congestion on

the road. In conclusion, the FTTLC clearly fails to adequately improve traffic flow and

reduce the time spent at the intersections.

1.4 Objective

1.4.1 Main objective

The objective of this project is to design an intelligent traffic signalling system to reduce

traffic congestion, unwanted time delay, detect LED light malfunctioning and to provide

smooth access for emergency vehicles.

1.4.2 Specific Objectives

a. Be able to simulate changing red and green times based on traffic density.

b. Be able to simulate detection of traffic light malfunctioning.

c. Be able to simulate the override feature to provide green light for emergency vehicles.

9

1.5 Significance of the project

This project will help reduce the time spent on the road intersections in cities and

urban areas in Ghana.

Through the provision of overrides for emergency vehicles, the end result will be the

saving of life and assisting in promoting state security.

The introduction of a monitoring system will help check the status of the traffic

systems and update the maintenance team to service any system failure and

malfunctions.

Moreover the findings of this work will add to existing knowledge.

1.6 Scope of the Project

The scope of the project encompasses the areas enlisted below;

a. Studying the traffic situation at the intersections on the Tech to Adum road in

Kumasi.

b. Designing a traffic signalling system that will operate based on traffic variation on an

intersection.

c. Reducing traffic congestion on intersections using Infra-red sensors to detect the

density of traffic on the roads and

d. Using radio frequency modules effectively to provide override feature for emergency

vehicles.

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1.7 Organisation of Study

The research work is organised as follows:

The first chapter outlines;

The introduction of the project and discuss the objectives and significance of the

project

The background study of traffic flow in Kumasi: define traffic flow, description of

Kumasi road network and the traffic situation at Bomso, Amakom and Anloga road

intersections.

The second Chapter introduces;

Traffic light system: historical background of traffic light, different types of traffic

light.

Strategies in traffic control: fixed and real time signals in controlling traffic.

Review of components such as PIC Microcontroller and sensors

Previous related works: findings of related researches done by others.

The third chapter illustrates;

The design methodology

Detailed description of components and item specifications

The fourth chapter presents;

System implementation and Simulations: simulate changing traffic density on an

intersection, simulate changing red and green times based on traffic density

Circuit analysis and results.

The fifth chapter gives;

Conclusion and relevance of the intelligent traffic system.

Limitation of the project work and recommended future works.

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CHAPTER TWO

LITERATURE REVIEW

2.1 Introduction

This chapter introduces the literature review of the project. The content of literature review is

one of the important steps to gather information about the project. It will explore the basic

history and evolution of traffic light system and also give some basic knowledge or

theoretical base that will serve as a foundation to successfully achieve the main objective of

the project. Most of the literatures are from the related articles, books and previous works of

the same field.

2.2 The Traffic Light

2.2.1 First Four Way Traffic Signal

William Potts of the Detroit Department is generally credited as the originator of the red-

yellow-green traffic signal. The signal, probably of the overhead suspension type, marked

another pioneering venture for Detroit when it was installed. He instituted electrical

interconnection of the signal of fifteen of Detroit’s traffic towers so that they could be

controlled by a police officer from a single location (Signalfan, 2015). With this system, a

timer controls the switching of the lights instead of a police controlling the traffic at the

intersection (Osborne, 2014; Willis, 2015).

Figure 2. 1 First Four Way Traffic Signal (Source: Willis, 2015)

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2.2.2 Light Emitting Diodes (LEDs) traffic light

It is made of arrays of light emitting diodes (LEDs). These are tiny electronic lights that are

energy efficient and last for long. Due to the tiny size of the LED hundreds of them are used

together in an array. The incandescent halogen bulbs are been replaced by LEDs in most

cities in the world because of its numerous advantages such as:

LEDs bulbs last for years, while halogen bulbs last for months. Replacing bulbs cost

huge sums of money and also create traffic on roads.

LED bulbs save a lot of money because it consumes less wattage of power as

compared to the incandescent halogen bulbs. Assuming a traffic light uses 100-watt

bulbs today and the lights are on 24 hours in a day, it means it will use 2.4kilowatt-

hours per day. The power consumption drops by a factor of five or six. These energy

bulbs can be run on solar energy instead of electrical lines to save money especially in

remote areas (Yakima Washington Department of Public Works Streets and Traffic

Division, 2015).

LED traffic lights can also be used as transmitters. According to Emad and Aman (2011)

several research has been done on LED traffic lights which suggest that its implementation

requires total overhaul of all the traffic lights and the introduction of cameras in vehicles to

facilitate communication.

Ibrahim and Beasley (1998) discussed the technical aspects of LED traffic lights and

provided estimates on expected savings if all traffic lights were to be replaced by LEDs.

Akanegawa et al., (2001) proposed a traffic information system using existing LED traffic

lights. Their study focused on the power and rays of the LED used in traffic control.

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2.3 The Controller Unit

Traffic signal controllers are control units that control and coordinate the traffic signals to

ensure traffic flow at a junction. They are classified into electromechanical and electronic

controllers. The electronic controllers include programmable logic control (PLC) controller,

peripheral Interface controller etc.

2.3.1 Electromechanical Controller

The electromechanical controllers are made of mechanical systems operated electrically.

They are mainly composed of movable parts - a dial timer, a solenoid and a cam assembly

together with electrical relays to control the signals. Cycle lengths of signalized intersections

are determined by small gears that are located within dial timers. Since a dial timer has only

one signalized intersection time plan, it control phases at a signalized intersection in only one

way. A motor and a gear assembly operate the dial timer which in turn is responsible to

energize or de energize a solenoid. The motor rotates a camshaft with cams which provides

current to each signal indications. The dial timer provides repetition of fixed time intervals

(Tarun, 2014). A lot of human ingenuity was involved to make this controller function so

well and fairly reliable in its time. There are quite a few of these in operation today, although

their numbers are slowly dwindling.

Figure 2. 2 An Electromechanical Controller (Source: the traffic signal museum, 2015)

14

2.3.2 Peripheral Interface Controller (PIC Microcontroller)

Peripheral interface controller (PIC) is a type of microcontroller developed by microchip. It is

fast and easy to implement programs and interface with other peripheral PIC as compared to

other microcontrollers like 8051. PIC consists of RAM, ROM, CPU, Timers, Counter Analog

to digital converters (ADC) and Digital to Analog (DAC). It supports protocols like CAN,

SPI, UART for interfacing with other peripherals (electronicshub, 2015)

PIC16F877A is an 8-bit microcontroller which has 40 pin DIP and is based on Harvard

Architecture. It features 256 bytes of EEPROM data memory, self-programming, an LCD, 2

Comparators, 8 channels of 10-bit ADC, 2 capture/compare/PWM functions, the synchronous

serial port can be configured as either 3-wire Serial Peripheral Interface for the 2-wire Inter-

Integrated Circuit bus and a Universal Asynchronous Receiver Transmitter. All of these

features make it deal for more advanced level A/D applications in automobile, industrial,

appliances and consumer applications. It has 8kb flash memory which can be used to erase

and rewrite the programs for the controller. Hence the device can be re-programmed up to

100, 000 times. The controller works with a low power supply such as 5V DC

(Shanmugasundaram et. al., 2013).

Figure 2. 3 A PIC16F877A Microcontroller (Source: electronicshub, 2015)

15

2.4 Sensors

There is a wide range of sensor technologies available for vehicle detection and traffic

monitoring systems. These include infrared sensors, inductive loop detector, video/ image

sensors etc.

2.4.1 Video/image sensors

An intelligent video sensor (IVS) combines image processing with video sensing and data

communication. It can be realized as an embedded system and capture a stream of video,

compute the data pertaining to high-level traffic parameters and transfer this video stream and

the computed traffic parameters to a base station. Traffic parameters may include vehicle

flow rate, average vehicle velocity as well as detection of obstacles. Video sensors usually

include video image processors (VIP) for processing the obtained images and videos. It is a

combination of hardware and software which extracts desired information from data provided

by an imaging/video sensor. The VIP can detect speed, count, occupancy and presence.

Because these sensors produce an image of several lanes, there is potential for a VIP to

provide a wealth of traffic information such as vehicle classification and incident detection.

The basic operation of a VIP can be described in the following manner: the operator selects

several vehicle detection zones within the field of view of the camera. Various image

processing algorithms are then applied in real time zones in order to extract the required

information such as vehicle speed or occupancy (Ashwini et al., 2014).

However advantages offered by these sensors are that, they are mounted above the road

instead of in the road, the placement of vehicle detection zones can be made by the operator,

the shape of the detection zones can be programmed for specific applications and the system

can be used to track vehicles.

16

Moreover the disadvantages associated with the sensors are that, detection of vehicles can be

blocked by objects and flying birds, reflections from the roadway and varying weather

conditions such as fog, rainfall etc. affect the sensor in monitoring vehicles on the road.

2.4.2 Inductive loop detector

It consists of wire embedded into a groove on the road surface which is sealed with a rubber.

It detects change in frequency. The inductor coil is connected with the detector which detects

the change in resonant frequency of the coil loop and accordingly controls the triggering of

the relay which is used to trigger the traffic signals. Basically it works on the principle that

when a car moves over the inductor coil, the inductance of the coil decreases, causing

resonant or oscillation frequency to increase. The electronic unit accordingly sends electric

pulses to the control unit to control the switching of traffic lights.

However a disadvantage of such system is that, the inductor loops are prone to

electromagnetic interference, i.e. electromagnetic radiation from other devices can also affect

the magnetic field and hence the inductance of the coil. They are also more prone to failure

and require high installation cost and also cause disruption of traffic (Tarun, 2013).

Figure 2. 4 Traffic Signal Control using Inductive Loop Detector (Source: Tarun, 2013)

17

2.4.3 Infra-red sensors

There are two types of infrared (IR) detectors. These are active and passive type detectors.

Active IR sensors operate by transmitting energy from either a light emitting diode (LED) or

a laser diode. A passive IR system detects energy emitted by objects in the field of view and

many use signal processing algorithms to extract the desired information. All objects emit

some form of energy, which is in the form of heat or thermal radiation. This radiation most

often falls in the IR spectrum which cannot be seen with the naked eye but can be detected by

an infrared sensor that accepts and interprets it. In vehicle sensing and detection, infrared

sensors are placed in line of sight across the road. Any time a vehicle blocks the

communication between the sensors, it sends information to the control unit which interprets

the signal and switches the traffic light to glow for a particle time based on the vehicle count

by the sensors (Ashwini et al., 2014).

Infra-red waves offer many advantages which include: transmission and reception of large

amount of data due to high frequency, not susceptible to adverse weather conditions and low

cost and power requirements. However it also has some disadvantages which include;

requires line of sight transmission which can easily be blocked by people and animals, it

cannot penetrate through walls, doors etc. and easily distracted by objects.

Figure 2. 5 Traffic Control using IR Sensors (Source: Tarun, 2013)

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2.5 Strategies in Traffic Control

Traffic control is the supervision of the movement of people, goods or vehicles to ensure

efficiency and safety. A traffic light system is an electronic device that assigns right of way at

an intersection or street crossing by means of displaying the standard red, yellow and green

coloured indications. Traffic light provides many advantages to cities and urban areas. It

ensures that pedestrians and bicyclists get their fair share of the road. It also prevents

accidents at road intersections since it regulates the movement of vehicles (Muhammad,

2011; Adewoye et al., 2014).

There are different strategies employed in controlling traffic which include fixed or pre-timed

signal and real time signal.

2.5.1 Fixed or Pre-timed Signal

At fixed timed traffic signals each signal phase or traffic movement is serviced in a

programmed sequence that is repeated throughout the day. Main street traffic receives a fixed

amount of green time followed by the amber and red clearance intervals. The same interval

timing is then repeated for the minor or side street. The amount of time it takes to service all

conflicting traffic movements is referred to as the cycle length. The signal timings and cycle

lengths may vary by time of day to reflect changes in traffic volumes and patterns. During

peak traffic periods for example, cycle lengths may range from 90-128 seconds to

accommodate heavier volumes, particularly on the busier arterial roadways. During off peak

times of day cycle lengths are reduced as traffic volumes are much lighter and therefore not

as much green time is required to effectively service all movements. With pre-timed signals

the pedestrian walk/don’t walk signal indications are automatically displayed in conjunction

with the green signal for vehicles. Fixed time control clearly defines signal program

19

elements, such as cycle time, stage sequence and duration of the green period. The signal

program is processed periodically (Sonja, 2012)

Pre-timed signals are best suited for intersections where traffic volumes are predictable,

stable and fairly constant. Once the timing programs are set, they remain fixed until they are

changed manually in the field. Pre-timed signals are cheaper to purchase, install and

maintained than real time signals (Ravi et al., 2012).

2.5.2 Real Time Signal

Real time signal combines preset cycle time with proximity sensors, which can activate a

change in the cycle time or the light. The real time data about traffic processes are used to

determine control or its modification. The proximity sensors in this system are used to detect

the presence of traffic waiting at the light and thus can avoid giving the green light to an

empty road while motorists on a different route are stopped. This reduces the delay at

intersections by providing the most effective green and red times and eliminate signal

changing altogether if there is no demand from any particular part of the road intersections.

However a timer is frequently used as a backup in case the sensors fail in real time control

(Adewoye et al., 2014).

2.6 Related works

Vikramaditya et al. (2012) designed an Image Processing Based intelligent Traffic Controller

with a camera fixed on poles and other tall structures to overlook the traffic scene. Images

extracted from the video are then analysed to detect and count vehicles. Their system was

able to allot time to each lane depending on the signal cycle. In addition, emergency vehicles

at road intersection were provided access when detected on a particular lane by giving the

lane a priority over the other lanes. One shortcoming with this system is that the camera is not

20

robust. The second problem is that when ambulances arrive from different lanes, the system

fails and gives green light to all lanes.

An algorithm to determine the number of vehicles on the road is presented in Naeem et al.

(2013). The density counting algorithm works by comparing the real time frame of live video

by the reference image. The computed vehicle density can be compared with other direction

of the traffic in order to control the traffic. A disadvantage of this system is that, video

processing is more time consuming and can often lead to delays during processing and thus

delays in transitions of traffic signal to various states (Red, Yellow, or Green). It is also

affected by the bad weather conditions like wind, rain, fog, etc. such that the images received

by the camera are distorted by noise and not clear for the system to identify the vehicle.

Priority Based Traffic Lights Controller using Wireless Sensor Networks was designed by

Shruthi and Vinodha (2012). Their system provided priority access for emergency vehicles.

Wireless Sensor Network is being used as communication infrastructure in the proposed

traffic light controller. System uses fuzzy logic to define direction of emergency vehicle.

Central monitoring system collects all information and gives appropriate response. A

disadvantage to this system is that data exchange in between sensors is not reliable and can

lead to more time delay at the junction when network is unavailable.

Dinesh and Swapnili (2012) designed an intelligent traffic signal control system which

incorporated infra-red sensors, microcontroller with programmable flash memory and built in

8-channels ADC. Their system was able to provide priority access for emergency vehicles via

detection by an infra-red sensor. However the limitation found in this system is that, the

infra-red device is not reliable since it is easily affected by climatic conditions.

Sarika and Gajanan (2013) designed an embedded system for Intelligent Ambulance and

Traffic control Management. Their system was able to provide the best path for emergency

21

vehicles by collecting information about the moving emergency vehicles through global

positioning system (GPS) and Global system for mobile communication (GSM) whiles

monitoring the density of traffic on roads to provide access to the more dense lanes through

the RFID device. Secondly the heart beat and temperature sensors in the ambulance provided

constant monitoring and reports on the health status of the patients through the GSM device

to a corresponding hospital. However the system is quite expensive in the implementation

since all vehicles on road should be equipped with RFID device and all ambulances should be

equipped with special instruments other than medical instruments which come with extra

cost.

Shweta and Amit (2014) designed a density signal management system with a Road Side

Unit (RSU) placed at junctions to track traffic density on roads. Their system also

implements wireless communication technology in every vehicle that communicates with the

RSUs. It provided access for multiple priority-based vehicles and controlled traffic

dynamically through the communication between the RSUs and wireless device placed in the

vehicles. The limitation associated with this system is that it is very expensive and difficult to

implement since all vehicles should be equipped with special communication device.

Nitksaz P. (2012) implemented an automatic traffic estimation using image processing. The

system estimates the size of traffic in highways by using a camera to detect the number of

vehicles on the highways and also detects the occurrence of accidents and violations on

highways. However the limitation associated with the system is that, it has extreme

sensitivity to light as sunlight causes interference with camera.

Hashim et al., (2013) designed a traffic light control system for emergency vehicles using

Radio Frequency. Their system receives signal from emergency vehicles based on radio

frequency transmission (RF) and uses a PIC16F877A microcontroller to trigger the system to

22

emergency mode giving priority for the emergency vehicle to move across the intersection.

However the limitation associated with their system is that, the system cannot identify the

direction of the emergency vehicle whether it is approaching from the north, east, west or

south towards the intersection and hence switch the whole system into emergency mode.

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CHAPTER THREE

DESIGN METHODOLOGY

3.1 Introduction

The methodology used to address the research problem is described in this chapter. It consists

of two sections. The first section introduces the design of the proposed system. The second

section describes the detailed hardware and software components used to implement the

system.

3.2 Design of the ITSS

The proposed system consists of three parts, namely: Main traffic control unit, the override

system unit and a monitoring control unit. The main block diagram of the ITSS is show in the

figure below;

Figure 3. 1 Block Diagram of Intelligent Traffic light Signalling system

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3.2.1 Main Traffic Control Unit

In this system, infra-red sensors are used to measure the density of the vehicles which are

fixed within a particular distance. All the sensors are interfaced with the PIC16F877A

microcontroller which in turn controls the traffic signal system according to the density

detected by the sensors. The density of vehicles is measured in three zones, i.e.; low, medium

and high based on which timings are allotted accordingly. Three Infra-red sensors are placed

across the road at a particular interval marking as low, medium and high. Each IR transmitter

faces an IR receiver opposite to each other across the road which is interfaced with a

microcontroller. The IR system gets activated whenever vehicles pass between the IR

transmitter and receiver. The microcontroller controls the IR sensors and assumes either low

medium or high density of traffic based on the activation of the IR sensors. At each direction

thus; north, south, east or west of the intersection, the microcontroller re-time the green light

signal based on the density at that particular direction. For high density, there will be more

time allotted and low density, less time allotted for traffic to flow respectively.

The block diagram of the traffic control unit is displayed in the figure below;

Figure 3. 2 Block Diagram of Main Traffic Control Unit

25

3.2.2 The Emergency System Unit

The override system provides priority access to emergency vehicles approaching the

intersection. It consists of a microcontroller, Global positioning System (GPS), a wireless

module (Radio frequency module) and a Liquid Crystal Display unit (LCD). The system gets

activated automatically at the start of the ignition key. The GPS device receives GPS

coordinates from orbiting satellites to locate the position of the emergency vehicle. The

coordinates received by the GPS are transmitted via the wireless RF transmitter to the control

unit of the traffic system. The LCD unit displays the status of the system to indicate whether

it is connected to the traffic system. The control unit in turn computes position, speed and

location of the emergency vehicle. The traffic controller overrides the set timing and switches

the green light till the vehicle cross the intersection.

The figure below displays the block diagram of the emergency system

Figure 3. 3 Block Diagram of Emergency System Unit

26

3.2.3 The Monitoring Control Unit

The monitoring control unit consists of a microcontroller, an alarm, Liquid Crystal Display

unit and RF module transceiver. It provides constant monitoring and update of the status of

the traffic light at the intersections. In the simulation, a fault button is connected to the main

traffic control unit which when activated causes the traffic light to go off. The controller then

report fault to the base station controller via the wireless device. When the base station

receives the signal, it triggers an alarm and display the information on the LCD board. The

figure below shows the block diagram of the monitoring control unit

Figure 3. 4 Block Diagram of Monitoring Control Unit

27

3.3 Hardware Components Description

In this section the main components used in the design of the ITSS are described below. It

covers the circuit description and components used in the design of the power supply and

detailed description of the other components used in the entire circuit design of the ITSS.

3.3.1 Power Supply

The power supply section is very important for all electronic circuits. The 220V, 50Hz AC

mains is stepped down by a transformer TR1 to deliver a secondary output of 12V AC power

supply. The transformer output is rectified by a full-wave rectifier comprising of a bridge

rectifier BR1 into a DC voltage source. The pulsating DC voltage is filtered by a 1000μf

capacitor C1 and regulated by 7812 voltage regulator U1 to obtain a constant 12v DC supply.

To obtain an alternate +5v DC supply to power the PIC16F877A, the 12v is further regulated

by a 7805 voltage regulator to provide a constant +5v DC power supply. Capacitors C2, C3,

to C6 are used respectively to further eliminate ripples present in the regulated power supply.

An LED-red (D1) act as the power indicator and R1 limits the current through LED-red (D1).

Bridge rectifier

A rectifier convert AC signal to a pulsating DC signal. The output from the step down

transformer is fed into the bridge rectifier. It converts A.C. into pulsating D.C. The rectifier

may be a half wave or a full wave rectifier. A bridge rectifier is used because of its merits like

good stability and full wave rectification. (Electronic Tutorials, 2016)

Capacitor

Capacitive filter is used in power supply circuit. It removes the ripples from the output of

rectifier and smoothens the D.C. Output received from this filter is constant until the mains

voltage and load is maintained constant. However, if either of the two is varied, D.C. voltage

28

received at this point changes. Therefore a regulator is applied at the output stage. (Electronic

Tutorials, 2016)

Voltage regulator

As the name itself implies, it regulates the input applied to it and gives a stable output. A

voltage regulator is an electrical regulator designed to automatically maintain a constant

voltage level. Power supply of 5V and 12V are required for Paper dispenser system. In order

to obtain these voltage levels, 7805 and 7812 voltage regulators are to be used. The first

number 78 represents positive supply and the numbers 05, 12 represent the required output

voltage levels. (Electronic Tutorials, 2016)

The circuit diagram of the power supply is displayed below;

Figure 3. 5 circuit diagram of the power supply

3.3.2 PIC 16F877A Microcontroller

PIC is a family of Harvard architecture microcontrollers made by microchip

technology, derived from the PIC1640 originally developed by general instrument’s

microelectronics division. PIC is popular due to their low cost, wide availability, large

user base, extensive collection of application notes, availability of low cost or free

29

development tools and serial programming (and re-programming with flash memory)

capability.

It is characterized by the following features: Separate code and data spaces (Harvard

architecture). A small number fixed length instructions which are simple cycle

execution (4 clock cycles) with single delay cycles upon branches and skips. A single

accumulator (W), the use of which (as source operand) is implied (i.e is not encoded

in the opcode). All RAM location function as registers as both source and/ or

destination of maths and other functions. A hardware stack for storing return

addresses. A fairly small amount of addressable data space (typically 256 bytes),

extended through banking, Data space mapped CPU, port and peripheral registers.

The program counter is also mapped into data space and writable( this is to implement

indirect) unlike most other CPU’s, there is no distinction “memory” and “register”

space because the RAM serves the job of both memory and registers and RAM is

usually just referred to as the register file or simply as the registers (Abinaya and

Uthira, 2014).

PIC 16F877 uses 14 bits for instructions which allows for all instructions to be one

word instructions. It is also typical for Harvard architecture to have fewer instructions to be

one word instructions. It is also typical for Harvard architecture to have fewer instructions

than Von Neumann’s and to have instructions to be executed in one cycle. The major

advantage with this architecture is that while an instruction is being executed the next

can be fetched. The execution speed is doubled. PIC uses Harvard architecture, so the size

of an instruction can be different from the size of the data. PIC 16F877A is one of the most

commonly used microcontrollers especially in automotive, industrial, appliances and

consumer applications. PIC16F877A is at the upper end of the mid-range series of the

microcontrollers developed by microchip Inc. It can be reprogrammed and erased up to about

30

100,000 times. Therefore it is very good for new product development phase. The memory of

PIC 16F877 chip is divided into three sections. They are; Program memory, Data memory

and Data EEPROM

Program memory: It contains the programs that are written by the user. The program counter

(PC) executes these stored commands one by one. Usually PIC16F877 devices have 13 bit

wide program counter that is capable of addressing 8K×14 bit program memory space. This

memory is primarily used for storing the programs that are written to be used by the PIC. The

PIC 16F877×A family has an 8-level deep × 13-bit wide hardware stack. The stack space is

not a part of either program or data space and the stack pointers are not readable or writable

(Vysakh, 2011).

Data memory: The data memory of PIC16F877 is separated into multiple banks which

contain the general purpose registers (GPR) and special function registers (SPR). The

PIC 16F877 chip has only four banks (BANK 0, BANK 1, BANK 2, and BANK 3).

Each holds 128 bytes of addressable memory.

Data EEPROM: The data EEPROM and flash program memory is readable and

writable during normal operation (over the full VDD range). This memory is not

directly mapped in the register file space; instead it is indirectly addressed through the

Special Function Registers. The EEPROM data memory allows single- byte read and

writes. The write operations automatically perform an erase before write on blocks of

four words. A byte write in data EEPROM memory automatically erases the location

and writes the new data (erase-before-write). The write time is controlled by on-chip

timer. The write/ erase voltages are generated by on-chip charge pump, rated to

operate over the voltage range of the device for byte or word operations (Vysakh,

2011).

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Figure 3. 6 Pin Diagram of the PIC 16F877A (Vysakh, 2011)

Pin Description

VSS and VDD: These are power supply pins. VDD is the positive supply and VSS is

the negative supply or 0V. The maximum supply voltage that you can use is 6V and

the minimum is 2V.

MCLR: Master clear (reset) input. This pin is an active low to the device. This pin is

used to erase the memory locations inside the PIC (i.e. when we want to re-program

it). In normal use it is connected to the positive supply rail.

OSC1/CLK IN and OSC2/CLKOUT: These are oscillator crystal input and output.

These pins are where we connect an external clock, so that the microcontroller has

some kind of timing. These are connected to crystal or resonator in crystal oscillator

mode.

32

Table 3. 1 pin description of the PIC circuit

Pin Name Pin No. Description Application

VDD 11, 32 Positive

supply (+5V)

Positive supply

to chip

VSS 12, 31 Ground

Reference

Ground

Reference

OSC 13, 14 20MHz

quartz crystal

Basic clocking

to the

microcontroller

MCLR 1 Reset input Connected to +5v

3.3.3 The Radio Frequency (RF) Module

The RF module, as the name suggest, operates at Radio Frequency. The corresponding

frequency range varies between 30 KHz and 300 GHz. In this RF system, the digital data is

represented as variations in the amplitude of carrier wave. This kind of modulation is known

as Amplitude shift keying (ASK).

The module comprises of an RF transmitter and receiver. The transmitter/receiver pair

operates at a frequency of 434 MHz. An RF transmitter receives serial data and transmits it

wirelessly through its antenna connected at pin 4. The transmission occurs at the rate of

1Kbps to 10Kbps. The transmitted data is received by an RF receiver operating at the same

frequency as that of the transmitter. The RF module is often used along with a pair of

encoder/decoder. The encoder is used for encoding parallel data for transmission feed while

reception is decoded by a decoder (engineersgarage, 2015). Pin diagram of RF transmitter/

receiver is displayed by the figure below;

33

Figure 3. 7 pin diagram of RF transmitter and receiver (Source: engineersgarage, 2015)

Pin Description:

Table 3. 2 Pin description of RF transmitter

Pin Number Function Name

1 Ground (0v) Ground

2 Serial data input pin Data

3 Supply voltage (5v) Vcc

4 Antenna output pin ANT

Table 3. 3 Pin description of RF receiver

Pin number Function Name

1 Ground(0v) Ground

2 Serial data output pin Data

3 Linear output pin; nit

connected

NC



34



8 Antenna input pin ANT

3.3.4 Liquid crystal display (LCD)

A liquid crystal display (LCD) is a thin, flat display device made up of any number of colour

or monochrome pixels arrayed in front of a light source or reflector. It is utilized in battery-

powered electronic devices as it uses small amount of electric power. In this proposed

system, LCD 20×4 LCD display is used to display fault detection at the monitoring unit of

the ITSS and also display the connection status of the emergency vehicle to the main traffic

control unit.

Table 3. 4 Pin description of 20×4 LCD display

Pin number Symbol Function

1 VSS Ground

2 VDD Supply voltage for

logical circuit

3 VEE Supply voltage for

LCD driving

4 RS A signal for selecting

registers

5 R/W A signal for selecting

read or write actions

6 E Enable signal for

reading or writing

35

data

7 DB0-DB7 8 bit data bus

Figure 3. 8 Pin Diagram of 20×4 LCD Display

3.3.5 Global Positioning System (GPS)

The Global Positioning System (GPS) is a satellite- based navigation system consisting of a

network of 24 satellites located into orbit. The system provides essential information to

military, civil and commercial users around the world and it’s freely accessible to anyone

with a GPS receiver. GPS works in any weather circumstances at anywhere in the world. A

GPS receiver must be locked on to the signal of at least three satellites to estimate 2D

position (latitude and longitude) and track movement (Abinaya and Uthira, 2014). With four

or more satellites in sight, the receiver can determine other information like speed, distance to

destination and time. GPS receiver used for this research work is installed in the emergency

vehicle to detect vehicle location and provide information to the main traffic control unit

through the radio frequency (RF) device.

36

Figure 3. 9 GPS Module (Source: Riscin, 2015)

3.3.6 Buzzer

A Buzzer is a signalling device, which may be mechanical, electromechanical or

piezoelectric. It is typically used in alarm devices, automobiles, household appliances such as

a microwave oven etc. it mostly consists of a number of switches or sensors connected to a

control unit that determines if and which button was pulsed or a preset time has lapsed. It

sounds a warning in a form of continuous or intermittent buzzing or beeping sound (tinkbox,

2015).

Specifications:

On-board passive buzzer

On-board 8550 triode drive

Working voltage: 5v

Pin configuration:

1. VCC

2. Input

3. Ground

37

Figure 3. 10 schematic diagram of 5v buzzer module (Source: tinkbox, 2015)

3.3.7 Infrared Transmitter

An electro luminescent IR LED is a product which requires care in use. IR LEDs are

fabricated from narrow band hetero structures with energy gap from 0.25 to 0.4 eV. Infra-red

transmitter emits IR rays in planar wave front manner. Even though Infrared ray spreads in all

directions, it propagates along straight line in forward direction. IR rays have the

characteristics of producing secondary wavelets when it collides with any obstacles in its path

(engineersgarage, 2015). When IR rays gets emitted from LED, it moves in the direction it is

angled. When any obstacle interferes in the path, the IR rays get cut and it produces

secondary wavelets which propagates mostly in return direction or in a direction opposite to

that of the primary waves, which produces the net result like reflection of IR rays.

Figure 3. 11 circuit diagram of IR Transmitter

http://2.bp.blogspot.com/_1YUZv5rd5AE/SGSYLT8uieI/AAAAAAAABTQ/pr_90bkHkm8/s1600-h/ir-transmitter.JPG

38

3.3.8 Infrared Receiver

Infrared photo receiver is a two terminal PN junction device, which operates in a reverse bias.

It has a small transparent window, which allows light to strike the PN junction. A photodiode

is a type of photo detector capable of converting light into either current or voltage,

depending upon the mode of operation. Most photodiodes will look similar to a light emitting

diode. They will have two leads, or wires, coming from the bottom. The shorter end of the

two is the cathode, while the longer end is the anode (engineersgarage, 2015).

A photodiode consists of PN junction or PIN structure. When a photon of sufficient energy

strikes the diode, it excites an electron thereby creating a mobile electron and a positively

charged electron hole. If the absorption occurs in the junction’s depletion region, or one

diffusion length away from it, these carriers are swept from the junction by the built-in field

of the depletion region. Thus holes move toward the anode, and electrons toward the cathode,

and a photocurrent is produced.

Figure 3.12 circuit diagram of IR receiver

http://1.bp.blogspot.com/_1YUZv5rd5AE/SGSY1DA6FTI/AAAAAAAABTY/8I-hbeujlfw/s1600-h/ir-receiver.JPG

39

3.4 Software Developing tools (description)

This section describes the software and the programming language used in the circuit design

and simulation of the ITSS. The ITSS was designed and simulated with Proteus ISIS 7

software. The instructions used for simulation was written using MikroC compiler which was

based on an algorithm in the flow chat shown in figure 3.14 below. The program was

compiled and the hex file generated from it was loaded unto PIC16F877A microcontroller.

3.4.1 Proteus ISIS 7

Proteus 7.0 is a virtual system modelling (VSM) that combines circuit simulation, animated

components and microprocessor models to co-simulate the complete microcontroller based

designs.

The tools for developing software and hardware for microcontroller based systems include

editors, assemblers, compilers, debuggers, simulators, emulators and device programmers. A

typical development cycle starts with writing the application program using a text editor. The

program is then translated into an executable code with the help of an assembler or compiler.

If the program has several modules, a linker is used to combine them into a single

application. Any syntax errors are detected by the assembler or compiler and must be

corrected before the executable code can be generated (Tomorrow Scientist, 2016). A

simulator is used to test the application program without the target hardware. Once the

program seems to be working, the executable code is loaded to the target microcontroller chip

using a device programmer and the system logic is tested. Debuggers and in-circuit emulators

analyse the program’s operation and display the variables and registers in real time with the

help of breakpoints set in the program. These software development tools are computer

programs that allow the programmer to create, modify, and test application programs (Ashok,

2014). The figure below shows the developing environment of Proteus ISIS 7.

40

Figure 3. 13 Proteus ISIS 7 development environment

3.4.2 MikroC

The mikroC PRO for PIC is a powerful, feature- rich development tool for PIC

microcontrollers. It is designed to provide the programmer with the easiest possible solution

to developing applications for embedded systems, without compromising performance or

control. PIC and C fit together well: PIC is the most popular 8-bit chip in the world, used in a

wide variety of applications and C, prized for its efficiency, is the natural choice for

developing embedded systems. MikroC PRO for PIC provides a successful match featuring

highly advanced IDE, ANSI compliant compiler, broad set of hardware libraries,

comprehensive documentation and plenty of ready- to- run examples (MikroElektronika,

2015).

41

3.4.3 Flow chart for the ITSS

Figure 3. 14 shows flow chart for the ITSS

42

CHAPTER FOUR

ANALYSIS AND RESULTS

4.1 Implementation of the Intelligent Traffic Signalling System (ITSS)

Figure 4. 1 schematic diagram of the ITSS

The figure above shows the schematic of the ITSS. The system is simulated for an

intersection consisting of lane one to lane four with each lane having an LED traffic light

mounted to control the flow of traffic. The sequence of the traffic light starts as green light at

lane one (L1) and red light for the other three lanes with each mode lasting for

3000milliseconds(ms). The light switches from green light to the amber for 500miliseconds.

Each lane also has two logic state indicators to represent IR sensors on the road. In this

simulation, 6000ms is assigned for high density whiles 3000ms is assigned for low density

respectively. The two logic state indicators are interfaced with the PIC16F887A which

switches to either 1 or 0 to indicate high or low density. Another indicator switch is

connected to the PIC16F887A to represent current sensors which can be toggled between 1

43

and 0 to introduce a fault in the LED traffic light. Upon activation, the PIC transmits signals

via the RF module TX to the RF module RX of the base controller unit. The LMO44L (20×4

LCD) displays the status of the system as ‘fault detection’ whiles a sound buzzer blows alarm

continuously. The emergency side is also made of a PIC16F887A which is interfaced with an

LM044L and a GPS module. It also has a logic toggle which upon activation triggers the PIC

to transmit GPS coordinates via the wireless RF module TX to the main traffic control unit.

4.2 Results for high density at lane two (L2)

Figure 4. 2 traffic light at lane two switched to green light for 6000ms

Figure 4.2 shows that when the two toggle switches at lane two were activated, the PIC

controller increased the green time allotted to lane two (L2) to 6000ms before switching to

the next lane.

44

4.3 Results for emergency override

Figure 4. 3 simulation of the emergency override

When the toggle switch was activated, the GPS coordinates received from the GPS module

was transmitted via the RF module to the main traffic controller. The controller overrode the

sequence of the traffic light and assigned green light to lane one (L1) based on the

coordinates received.

45

4.4 Results for system failure of the LED traffic light

Figure 4. 4 results for system failure of the LED traffic light

When the logic toggle was activated, the LED traffic light went off; this triggered the

controller to transmit signals via the RF module TX to the base controller. The LM044L at

the base station displays ‘fault’ and the buzzer blows alarm continuously.

46

4.5 Results for malfunctioning of a particular LED traffic light

Figure 4. 5 shows simulation results for malfunctioning of a particular LED traffic light

Considering the figure above, the main traffic control unit upon receiving GPS coordinates

from the emergency vehicle assigned green light to the respective lane (L3) even though the

two toggle switches at lane two (L2) were activated to indicate high density. The logic state

indicator for fault detection was activated to render the LED light at lane four inactive. This

triggered the controller to transmit signals via the RF module TX to the base station

controller. The buzzer blows alarm whiles the LM044L displays the status of the traffic light

as “fault”.

47

CHAPTER FIVE

Conclusion and Recommendations

5.1 Conclusion

The primary objective of this study was to design and simulate an intelligent traffic signalling

system to reduce traffic congestion, unwanted time delay, detect light malfunctioning and to

provide smooth access for emergency vehicles.

Proteus ISIS 7 was used together with MikroC in the design and simulation of the ITSS.

After the design and simulation of the system, the results show that the system was able to

change red and green times based on traffic density, detect malfunction of traffic light and

provide access for emergency vehicles.

However there were also many challenges that were met in the designing of the ITSS. The

simulation software (Proteus ISIS 7) used could not take into account certain parameters such

as behaviour of drivers and nature of roads. The limitation associated with this system is that

the RF module TX/RX which serves as the main communication medium in the simulation

cannot travel far.

5.2 Recommendations

The results obtained from this research can easily be implemented and integrated in the

existing system to help optimize traffic congestion in the city and the country at large. The

design of the ITSS can further be enhanced by replacing the infra-red sensors with imaging

systems/camera systems in other to have a wide range of detection capabilities.

Consequently the recommended future work may be oriented on studying the traffic variation

in Ghana so as to synchronize all the traffic junctions in the cities by establishing a network

among them. This will help provide useful information such as traffic situation on roads,

48

accident and vehicle tracking to motorist, security and other organisations to ensure safety

and at large reduce traffic congestion on roads in Ghana.

49

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Appendix

Code for the main traffic unit

char started, count;

char command, value, ok;

int fault = 0;

int allow = 0;

void RF_Send(char command, char value)

{

char checksum = ~(char)(command + value);

UART1_Write(0xFF); //Start

delay_ms(10);

UART1_Write(command); //Comando

delay_ms(10);

UART1_Write(value); //Valor

delay_ms(10);

UART1_Write(checksum); //Checksum

delay_ms(10);

}

void RF_Read(char *Cmd, char *Val, char *Ok)

{

char buffer;

char checksum_byte;

*Ok = 0;

if(PIR1.RCIF)

{

buffer = UART1_Read();

if(started)

{

count++;

if(count == 1)

{

*Cmd = buffer;

}

if(count == 2)

{

*Val = buffer;

}

if(count == 3)

{

checksum_byte = buffer;

started = 0;

if(checksum_byte == ~(char)(*Cmd + *Val))

{

*Ok = 1;

}

}

}

else

{

if(buffer == 0xFF)

{

started = 1;

count = 0;

}

}

}

}

void Interrupt()

{

RF_Read(&command, &value, &ok);

if(ok == 1)

{

if(command == 'A')

{

allow = 1;

}

else

{

allow = 0;

}

}

if(INTCON.INTF)

{

fault = 1;

INTCON.INTF = 0;

//goto fault;

}

}

void RF_Init()

{

UART1_Init(9600);

Delay_ms(100);

}

void RF_Receive_Init()

{

RCIE_bit = 1;

GIE_Bit = 1;

PEIE_Bit = 1;

INTE_bit = 1;

}

void main()

{

TRISD = 0b11000000;

TRISB = 0b00000001;

TRISC = 0b10111111;

ADCON0 = 0x00;

ADCON1 = 0x0F;

PORTD = 0x00;

PORTB= 0x00;

RF_Receive_Init();

RF_Init();

SPBRG = 255;

BRGH_bit = 0;

fault = 0;

while(1)

{

//Lane 1

PORTD = 0b00001100;

PORTB = 0b00010010;

if(PORTD.F7 == 1 && PORTD.F6 == 1 )

delay_ms(6000);

else

delay_ms(3000);

PORTD = 0b00001010;

if(fault == 1 || allow == 1) goto faulting;

delay_ms(500);

//Lane 2

PORTD = 0b00100001;

PORTB = 0b00010010;

if(PORTC.F0 == 1 && PORTC.F1 == 1 )

delay_ms(6000);

else

delay_ms(3000);

PORTD = 0b00010001;


delay_ms(500);

//Lane 3

PORTD = 0b00001001;

PORTB = 0b00011000;


delay_ms(6000);

else

delay_ms(3000);

PORTB = 0b00010100;


delay_ms(500);

//Lane 4

PORTD = 0b00001001;

PORTB = 0b01000010;


delay_ms(6000);

else

delay_ms(3000);

PORTB = 0b00100010;

delay_ms(500);

faulting:

while(fault)

{

PORTB.F7 = 1;

PORTD = 0b00000000;

PORTB = 0b00000000;

delay_ms(500);

RF_Send( 'F', 1);

}

while(allow)

{

PORTD = 0b00001100;

PORTB = 0b00010010;

while(fault)

{

PORTD = 0b00001001;

PORTB = 0b00001001;

RF_Send( 'F', 1);

delay_ms(500);

}

delay_ms(500);

}

}

}

Code for the monitoring unit

sbit LCD_RS at RB2_bit;

sbit LCD_EN at RB3_bit;

sbit LCD_D4 at RB4_bit;




sbit LCD_RS_Direction at TRISB2_bit;

sbit LCD_EN_Direction at TRISB3_bit;

sbit LCD_D4_Direction at TRISB4_bit;




// End LCD module connections

char started, count;

short fault = 0;

void RF_Read(char *Cmd, char *Val, char *Ok)

{

char buffer;

char checksum_byte;

*Ok = 0;

if(PIR1.RCIF)

{

buffer = UART1_Read();

if(started)

{

count++;

if(count == 1)

{

*Cmd = buffer;

}

if(count == 2)

{

*Val = buffer;

}

if(count == 3)

{

checksum_byte = buffer;

started = 0;

if(checksum_byte == ~(char)(*Cmd + *Val))

{

*Ok = 1;

}

}

}

else

{

if(buffer == 0xFF)

{

started = 1;

count = 0;

}

}

}

}

char command, value, ok;

void Interrupt()

{

RF_Read(&command, &value, &ok);

if(ok == 1)

{

if(command == 'F')

fault = 1;

}

if(INTCON.INTF)

{

fault = 0;

INTCON.INTF = 0;

}

}

void RF_Init()

{

UART1_Init(9600);

Delay_ms(100);

}

void RF_Receive_Init()

{

RCIE_bit = 1;

GIE_Bit = 1;

PEIE_Bit = 1;

INTE_bit = 1;

}

void main()

{

Lcd_Init(); // Initialize LCD

Lcd_Cmd(_LCD_CLEAR); // Clear display

Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off

Lcd_Out(1,2,"Traffic Monitoring");

Lcd_Out(2,10,"By");

Lcd_Out(3,8,"Konadu");

delay_ms(1000);

Lcd_Cmd(_LCD_CLEAR);

Lcd_Out(1,2,"Traffic Monitoring");

Lcd_Out(2,1,"--------------------");

Lcd_Out(3,1,"System: ACTIVE");

Lcd_Out(4,1,"Condition: Normal");

TRISB = 0x03;

TRISC = 0b10000000;

RF_Init();

SPBRG = 255;

BRGH_bit = 0;

RF_Receive_Init();

Sound_Init(&PORTC, 3);

Sound_Play(880, 1000); // Play sound at 880Hz for 1 second

while(1)

{

PORTB.F7 = 1;

delay_ms(500);

while(fault)

{

Lcd_Out(4,1,"Condition: Fault ");

Sound_Play(659, 250); // Frequency = 659Hz, duration = 250ms



delay_ms(100);

}

Lcd_Out(4,1,"Condition: Normal");

PORTB.F7 = 0;

delay_ms(500);

}

}

Code for the emergency unit

// LCD module connections

sbit LCD_RS at RB2_bit;

sbit LCD_EN at RB3_bit;





sbit LCD_RS_Direction at TRISB2_bit;

sbit LCD_EN_Direction at TRISB3_bit;





// End LCD module connections

char *Output;

char* codetxt_to_ramtxt(const char* ctxt){

static char txt[20];

char i;

for(i =0; txt[i] = ctxt[i]; i++);

return txt;

}

void RF_Send(char command, char value)

{

char checksum = ~(char)(command + value);

UART1_Write(0xFF); //Start

delay_ms(10);

UART1_Write(command); //Comando

delay_ms(10);

UART1_Write(value); //Valor

delay_ms(10);

UART1_Write(checksum); //Checksum

delay_ms(10);

}

void RF_Init()

{

UART1_Init(9600);

Delay_ms(100);

}

void main()

{

Lcd_Init(); // Initialize LCD

Lcd_Cmd(_LCD_CLEAR); // Clear display

Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off

Lcd_Out(1,2,codetxt_to_ramtxt("Emergency Override"));

Lcd_Out(2,10,codetxt_to_ramtxt("By"));

Lcd_Out(3,8,codetxt_to_ramtxt("Konadu"));

delay_ms(500);

Lcd_Cmd(_LCD_CLEAR);

Lcd_Out(1,2,codetxt_to_ramtxt("Emergency Override"));

Lcd_Out(2,2,codetxt_to_ramtxt("------------------"));

Lcd_Out(3,2,codetxt_to_ramtxt("System: ACTIVE"));

Lcd_Out(4,2,codetxt_to_ramtxt("Status: IDEAL"));

ADCON1 = 0x0F; //Desativa as portas analógicas(PORTA e PORTB)

TRISB = 3;

TRISD = 0x1F;

RF_Init();

SPBRG = 255;

BRGH_bit = 0;

while(1)

{

while(PORTD.F4 == 1)

{

//Lcd_Out(3,2,"Direction: NORTH");

Lcd_Out(3,2,codetxt_to_ramtxt("Sending: "));

Lcd_Out(4,2,codetxt_to_ramtxt("GPS Coordinates..."));

if (UART1_Data_Ready() == 1) { // if data is received

UART1_Read_Text(output, ",", 20); // reads text until 'OK' is found

UART1_Write_Text(output); // sends back text

}

RF_Send('A', 1);

}

Lcd_Out(3,2,codetxt_to_ramtxt("System: ACTIVE "));

Lcd_Out(4,2,codetxt_to_ramtxt("Status: IDEAL "));

RF_Send('B', 1);

delay_ms(500);

}

}

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