GHANA TECHNOLOGY UNIVERSITY COLLEGE (GTUC)

FACULTY OF ENGINEERING

DEPARTMENT OF TELECOMMUNICATION ENGINEERING

TITLE:

INSTALLATION OF FIBER OPTIC CABLES IN DEVELOPING COUNTRIES USING LINK SENSOR TECHNOLOGY.

A Project work in Partial Fulfillment of the Requirements for the Award of

BSc. In Telecommunication Engineering

BY:

BERNARD BLEWUSI AGBLEVOR (B040113015)

AND

NATHANAEL SHAMO ABBEY (B040113002)

SUPERVISOR: ALEXANDER OSEI-OWUSU

JULY 2015

DECLARATIONThis project is presented as part of the requirements for BSc. In Telecommunication

Engineering awarded by Ghana Technology University College. We hereby declare that

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

however been acknowledged with due respect.

Authors Signature

BERNARD BLEWUSI Agblevor (B040113015) ………………………

NATHANAEL SHAMO ABBEY (B040113002) ……………………….

Date:…………………...

Supervisor:

Alexander Osei-Owusu ……………………….

Date:…………………...

Head, Faculty of Engineering:

Dr. Adjin ……………………….

Date:…………………...

ii

ABSTRACTThe project is about developing remote sensing and signaling device to protect installed

fiber cables which are often under threat of damage by external agents such as

trenching.

The device was built using a microcontroller unit –Arduino Uno. This will serve as the

processing unit for sensing and remote signaling. When there is a disturbance at a

particular segment, the piezo disc converts the mechanical vibrations into an electrical

voltage. The microcontroller processes the signal and a voltage is sent to a LED

indicator switching it on to indicate where the disturbance is occurring.

With the link sensor in place, location of faults will be easily identifiable for restoration

work to be done very fast. And this will minimize the downtime the Telcos are likely to

face

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TABLE OF CONTENTSGhana technology university college (gtuc).......................................................................i

Declaration....................................................................................................................... ii

Abstract............................................................................................................................ iii

List of Tables.................................................................................................................. vii

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

1.1 Background to the study.........................................................................................1

1.2 Problem Statement.................................................................................................2

1.3 Research Questions...............................................................................................3

1.4 Research Objectives..................................................................................................3

1.5 Significance of the research.......................................................................................3

CHAPTER TWO...............................................................................................................4

2.0 LITERATURE REVIEW..............................................................................................4

2.1 INTRODUCTION........................................................................................................4

2.2 Communication through Fiber Optic Medium.............................................................4

2.3 Fiber Design...............................................................................................................5

2.3.1 Types of Trenches.............................................................................................52.3.2 Ducting and Civil Works.....................................................................................82.3.4 Manholes – Access Chambers..........................................................................8

2.4 Installation Types or Methods................................................................................10

2.4.1 Aerial............................................................................................................10

2.4.2 Underground Cable installation......................................................................112.4.3 Direct Buried/Buried Cable............................................................................132.4.4 Submarine/Underwater Cabling.....................................................................14

2.5 SAMPLE 1: THE USE OF Warning tape TO PROVIDE FIBER SECURITY............14

2.5.1 Limitation of warning tape................................................................................152.5 SAMPLE 2: Protecting Fiber using Bricks................................................................15

2.5.2 Limitation of warning bricks..............................................................................162.7 Summary of Literature Review...............................................................................18

CHAPTER THREE.........................................................................................................19

3.1 Methodology...........................................................................................................19

3.1.1 Description of Elements of Block Diagram.......................................................213.2 DETAILED SCHEMATIC DIAGRAM........................................................................21

3.2.1 At the Input......................................................................................................22

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3.2.2 At the Output....................................................................................................223.3 Specifications...........................................................................................................23

3.4 Description of pins connection.................................................................................23

3.5 Background of Components.....................................................................................24

3.5.1 Microcontroller Unit –Arduino Uno...................................................................243.5.3 Zener Diode.....................................................................................................263.5.4 Light-emitting Diode (LED)...............................................................................273.5.5 Resistor............................................................................................................283.5.6 Buzzer Alarm...................................................................................................29

4.0 CONSTRUCTION, TESTING, RESULTS AND ANALYSIS:....................................31

4.1 CONSTRUCTION:...................................................................................................31

4.2 TESTING..................................................................................................................31

4.3 RESULTS AND ANALYSIS......................................................................................32

4.4 ANALYSIS................................................................................................................32

CHAPTER FIVE.............................................................................................................34

5.0 CONCLUSION AND RECOMMENDATION.............................................................34

5.1 Conclusion...............................................................................................................34

5.2 Limitation..................................................................................................................34

5.3 Recommendation.....................................................................................................34

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LIST OF FIGURES

Figure: 2.1 (The FOA_Guide To Fiber Optic and Premises Cabling-2014) Pictorial view of fiber………………………….………..…………..……………...………….………………...4

Figure: 2.2 (The FOA_Guide To Fiber Optic and Premises Cabling-2014) Optical Fiber Parts………………………………………………………………………………………..….…5

Fig. 2.3 (MTN Gh – Fiber Optic Network Expansion- 2014)…………………..……….…..6

Fig. 2.4 (MTN Gh – Fiber Optic Network Expansion- 2014)…………………………….…6

Fig. 2.5 (MTN Gh – Fiber Optic Network Expansion- 2014)…………………………....….7

Fig. 2.6 (MTN Gh – Fiber Optic Network Expansion- 2011…………………………..….…7

Fig. 2.7 Manhole Specification (MTN Gh – Fiber Optic Network Expansion- 2014)….…9

Fig. 2.8 Precast manholes with four way sub duct entry and manhole dimension measurements (MTN Gh – Fiber Optic Network Expansion- 2014)……………………..10

Figure: 2.9 (Field Picture 2014) Concrete protect for HDPE in rocky area in Central Business District (CDB) Accra……………………………………………………………..…11

Figure: 2.10 (Field Picture 2014) OSP Fiber Optic cable across a bridge…………...….12

Figure: 2.11 (Field Picture 2014) Truss boring under existing road structure………......12

Figure: 2.12 (Field Picture 2014). This is a simple and less expensive technology used to cross a storm drain……………………………………………………………………...….13

Fig 2.13 Warning tape…………………………………………………………………..…….14

Fig. 2.14 (Field picture 2015) HDPE and Warning tape in trench………………..………14

Fig 2.15 Damage caused to fiber optic cable although there is a warning tape (2015)..15

Fig. 2.16 Laying Bricks in trenches to protect Fiber……………………………………..…16

Fig 2.17 Single ended configuration showing light path……………………………….…..17

Fig 3.1 Using a piezoelectric cable as a link sensor to prevent fiber optic cable cuts….20

Fig 3.2 General Block Diagram of the design concept…………………………………….20

Fig 3.3 Schematic diagram of circuit…………………………………………………….…..21

Fig 3.4 Microcontroller Unit –Arduino Uno…………………………………………...……..24

vi

Fig 3.5 Zener diode…………………………………………………………………………....27

Fig 3.6 Blue, pure green, and red LEDs in 5 mm diffused cases……………………..….28

Fig 3.7 Several different types of resistors…………………………………………….……29

Fig 3.8 Buzzer alarm……………………………………………………………………….….29

Fig 4.1 Prototype of circuit on a board……………………………………………………....30

Fig 4.2 Prototype of circuit on a board……………………………………………………....31

vii

LIST OF TABLESTable 3.1 ……………………………………………………………………………………………………………………………………………23

viii

LIST OF ABBREVIATIONS

NCA: National Communication Authority

OSP: Outside Plant

FOA: Fiber Optic Association

ROW: Right of Way

PVC: Polyvinyl Chloride

HDPE: High Density Polyethylene

MCU: Microcontroller Unit

PC: Personal Computer

LED: Light Emitting Diode

USB: Universal Serial Bus

PWM: Pulse Width Modulation

PN JUNCTION: Positive Negative Junction

PCB: Printed Circuit Board

ix

ACKNOWLEDGEMENT

Our immense gratitude goes to God Almighty for guidance, grace and for giving us the

strength, resources and the endurance during the project and throughout BTE program.

Our deepest appreciation also goes to our project supervisor Alexander Osei Owusu

(BSc, MSc, PhD Fellow) for his guidance and encouragement which has largely

contributed to the successful completion of this study.

Lastly, we wish to express our sincere gratitude to our families for their financial support

and to Nana Boamah (BSc, MSc) of GTUC Telecom Engineering department for his

constructive criticism and recommendations during the construction of the prototype.

x

CHAPTER ONE

1.1 BACKGROUND TO THE STUDY

The use of Fiber Optic in telecommunication services has become common in recent

time and this is due to the increasing demands of bandwidth needed by the telecom

companies to transmit customer data, voice and video at the fastest possible time.

Increasing technological demands is also putting so much pressure on the copper

cables and have rendered the use of the copper by telecom companies inefficient in the

modern world.(FOA 2013)

Telecom companies have suffered an upsurge of fiber optic cable cuts mainly caused

by road construction and other construction activities across the country. Statistics from

the Telecoms Chamber suggests that telecom companies in the country last year 2014

suffered a 30 per cent increase in cable cuts and this put to total of 2110 cable cuts

compared to 1,605 in 2013 and 480 in 2012.

It was also recorded that three-quarters of the cuts occur during road construction,

followed by small-scale illegal mining, which is responsible for 10 per cent of cuts. The

rest are theft, vandalism and bushfires.

Network challenges such as call drops, speech mutation, poor voice signals and quality

among others are attributed to rampant cuts in underground fibre optic cables during

road construction and other development activities. (NCA 2014).

Between 80 and 90 per cent of transmissions of all the telcos pass through fibre hence

a cut or puncture affects service quality greatly. The fibre optic cable has bigger

capacity to carry more calls and data compared to microwave and the satellite systems.

MTN, the largest communication service provider in Ghana, recorded 506 cuts in 2012,

and this increased to 804 cuts in 2013, and by June this year, the company had already

recorded 436 cuts. (www.graphic.com.gh 2014).

1

In particular this research is aimed developing at a device that can detect disturbances

of any form, giving clear location of such a disturbances so that further or no damage

can be done to the fiber cables buried underground

1.2 PROBLEM STATEMENT Research has shown that, human error is by far the most common cause of cable

damage and failure, accounting for over 40% of all fiber optic cable malfunctions (NCA

2014). Many communication companies today face the challenge of fiber optic cable

relocation due to improper route designs (NCA 2014). Construction of new roads and

building projects accounts for relocation of fiber network infrastructure.

Fiber optic cables are needed to facilitate enhanced access to broadband services for

all persons living in Ghana. However these are being cut regularly, sometimes on a

daily basis, resulting in disruption of vital communications services to schools, hospitals,

disaster areas, and the general public. The already huge investment cost of these

infrastructure makes it hard for telco’s to devote human resources to protect every

length of communication fiber optic cable worldwide.

This situation is becoming quite worrisome to the communications industry as a whole

and particularly to the NCA as Regulator of the communications sector as it creates

numerous challenges including poor quality of service delivery to consumers of

communications services as well as unplanned costs to Telecom Operators. It also

impedes the achievement of government’s universal access and service policy goals of

providing and enhancing access to quality broadband internet and other

communications services to all citizens of Ghana particularly those living in underserved

communities.

This study is devoted in finding a much easy, effective and cost effective way of

protecting and minimizing fiber cut buy developing a sensor and signaling device that

can aid our effort.

2

1.3 RESEARCH QUESTIONS How will deployment of the link sensor improve restoration time when a fiber cut

occurs?

How can the link sensor enhance monitoring of the installed fiber cable and

thereby protect it against potential damage?

1.4 RESEARCH OBJECTIVES Design and simulation of a link sensor mechanism which has the intelligence of

detecting and showing exact location of fiber optic cable attack and disturbance.

1.5 SIGNIFICANCE OF THE RESEARCH

The outcome of this study will help minimize fiber cuts by the deployment of the

link sensor.

With the link sensor in place, location of faults will be easily identifiable for

restoration work to be done very fast. And this will minimize the downtime the

Telco’s are likely to face.

This research will also help minimize the amount of trenching done by the

maintenance team in detecting the exact location of the fault. Since the exact

location would have been communicated to the team.

3

CHAPTER TWO

2.0 LITERATURE REVIEW

2.1 INTRODUCTIONThis chapter presents a review of relevant literature concerning the subject under study.

We examine how outside plant (OSP) fiber is laid by the various telecommunication

companies in Ghana and in other jurisdictions. We also examine the procedure and the

practices employed by the Telco’s in laying their fiber cable.

2.2 COMMUNICATION THROUGH FIBER OPTIC MEDIUMFiber Optics is the communications medium that works by sending optical signals down

hair-thin strands of extremely pure glass or plastic fiber. The light is "guided" down the

center of the fiber called the "core". The core is surrounded by an optical material called

the "cladding" that traps the light in the core using an optical technique called "total

internal reflection." The fiber itself is coated by a "buffer" as it is made to protect the

fiber from moisture and physical damage. The buffer is what one strips off the fiber for

termination or splicing.

Figure: 2.0 (The FOA_Guide to Fiber Optic and Premises Cabling-2014) Pictorial view of fiber.

4

Cladding

Core

2.3 FIBER DESIGNThe construction of a fiber optic cable consists of a core, cladding, coating buffer,

strength member and outer jacket.

Figure: 2.1 (The FOA_Guide to Fiber Optic and Premises Cabling-2014) Optical Fiber Parts

2.3.1 Types of Trenches

Specific characteristics such as dimensions, filling, position and dimension of ducts, etc.

for each proposed trenching solutions would be defined. It is expected however that the

Installer will closely follow these configurations during installations to provide security for

the installed fiber. (MTN GH – Fiber Optic Network Expansion- 2011).

Road Sections

Road Configuration – R1

The ducting structure will consist of 4 x HDPE 40mm ducts, with sand filling. The trench

will be backfilled with "sand" (normally the same material that was extracted from the

trench). A warning tape will be laid along the whole length of the trench to prevent

accidental damage to the ducts.

5

90

c m

Existing Pavement/Road…

TrenchR2

…

Extracted Materials

Sand

Readymix Concrete (20 cm)

15

cm90

c m

Existing Pavement/Road…

TrenchR2

…

Extracted Materials

Sand

Readymix Concrete (20 cm)

15

cm

Fig. 2.2 (MTN GH – Fiber Optic Network Expansion- 2014).

Road Configuration – R2

The ducting structure will consist of 4 x HDPE 40mm ducts, with backfill sand and an

intermediate concrete layer.

Fig. 2.3 (MTN GH – Fiber Optic Network Expansion- 2014).

Road Configuration – R3

The ducting structure will consist of 4 x HDPE 40mm ducts, with concrete filling

6

90

c m

Existing Pavement/Road…

TrenchR3

…

Extracted Materials

Readymix Concrete

15

c m

10

c m

90

c m

Existing Pavement/Road…

TrenchR4

…

Extracted Materials

Sand

30

cm

Fig. 2.4 (MTN GH – Fiber Optic Network Expansion- 2014).

Road Configuration – R4

The ducting structure will consist of 2 x HDPE 40mm ducts, with sand filling. The trench

will be backfilled with typically the same material that was extracted from the trench. A

warning tape will be laid along the whole length of the trench to prevent accidental

damage to the ducts. The depth of the trench will be sufficient to provide a level of

security.

Fig. 2.5 (MTN GH – Fiber Optic Network Expansion- 2014.

7

2.3.2 Ducting and Civil Works

The ducting infrastructure consist of a trenched duct, or set of ducts, that runs parallel to

the roadside, through the acquired Right Of Way (ROW). The fiber optic cables are

pulled through this ducts to provide security to them.

The trenches contain 2 or 4 x 40mm HDPE ducts that are buried at a sufficient depth to

provide reasonable protection against vandalism and erosion. The trench will be

properly marked for maintenance and repair purposes. (MTN GH Fiber Optic Network

Expansion 2014).

Ducts should be cut with a suitable cutting tool, the inside end beveled to form a bell

mouth. All cut ends should be square to the axis of the duct and all burrs removed

before jointing is carried out using a specific collar.

PVC ducts will be manually laid on horizontal and well compacted bedding. They should

be laid so that the spigot end is always in the same direction. They will be bound by

means of plastic rings every 6m as to ensure to maintain their initial position expecting

addition of the padding and back-filling materials.

HDPE will be laid manually or mechanically upon method selected by the installer and.

In case of manual installation they will be maintained in the initial position by means of

rings. In case of mechanical installation (sloughing) with immediate back-filling, the

permanent respective position of ducts will be ensured by a gate behind the laying

shear hosting the number of ducts to install.

2.3.4 Manholes – Access Chambers

Dimensions and Mechanical Resistance: As to allow easily splice box installation and

cable coils with respect of maximum bending radii, the dimensions of the manhole will

not be less than: Internal Length: 1.20 m - Internal Width: 0.50 m - Internal Depth: 0.60

m The grading up of ducts to enter into manholes due to the internal depth of the

manhole should be minimized. Lateral walls and covers will be resistant to a minimum

of: 400 KN for manholes under roadways 250 KN for manholes buried in verges or

sideways Position: It is expected that the manhole should be placed at the end of each

8

set of inner duct reels and at no greater distance than: 3 km on the Long Distance

network. If the Installer proposes a distance greater than this upper bound then they

should provide the reasoning and also explain how maintenance factors will not be

compromised. 500m (subject to design) in urban areas unless otherwise approved.

Where bridges, streams or other obstacles require crossing, chambers should be

placed on either side of the obstruction. These methods are therefore employed to give

protection to the fiber infrastructure at the joints.

Fig. 2.6 Manhole Specification (MTN GH – Fiber Optic Network Expansion- 2014).

9

Fig. 2.7 Precast manholes with four way sub duct entry and manhole dimension measurements (MTN Gh – Fiber Optic Network Expansion- 2014).

Most of the manhole are securely constructed and looks safe but most of the fiber cuts

usually occur along the cable which laid along the road and not the chamber. So it is

good to secure the chamber because that is where fiber cables from various LEGS are

joined but still does not solve the problem of fiber cut.

With regards to the chamber, although usually secured when constructed, they are

mostly not managed properly by maintenance workers who occasionally do work on

them sometimes even left open which could lead to the tempering of the cables. As a

result the security of the fiber cable is compromised.

2.4 INSTALLATION TYPES OR METHODSAccording to FOA, OSP installations fall into four broad categories, and each uses

different procedures, tools and even cables. The following are the four main categories:

i. AERIAL

ii. UNDERGROUND

iii. DIRECT BURIED

iv. SUBMARINE (underwater)

10

2.4.1 Aerial

Although most optical fiber cables are intrinsically lightweight, they are subject to

stresses caused by the environment they are installed in. Cables located in aerial runs

can be affected by wind and creating a situation that can cause the cable to stretch or

sag, pulling on the fiber. Under most conditions aerial optical fiber cables should be

supported by an external support member, suspension strand, or “messenger”. Strong

“wires” made of steel are positioned and secured to utility poles along the desired route.

The cable is then placed along the route under the messenger, lifted into place and

lashed or tied to the messenger with a steel or dielectric thread. Lashing can be

accomplished using standard lashers designed for this purpose. Lashing strands

should be chosen in accordance with guides associated with the lashing tool. As a

general rule, there should be at least one wrap of the lashing wire per foot.

2.4.2 Underground Cable installation

Underground cables are pulled in conduit/HDPE that is buried underground, usually (1-

1.2 meters) deep to reduce the likelihood of accidentally being dug up. The process

usually begins with digging a trench to bury the HDPE which is generally 34mm

diameter, sometimes with pre-installed inner duct (also called duct liner) with a pulling

tape to facilitate the actual cable pulling process. Directional boring can also be used to

avoid digging up the surface, for example in crossing streets or sidewalks. If the conduit

and cables are all dielectric, a conductive marker tape may be buried about 0.31m

above the HDPE to assist in future cable location and as a warning to anyone digging in

the vicinity of the cable.

11

Figure: 2.8 (Field Picture 2014) Concrete protect for HDPE in rocky area in Central Business District (CDB) Accra.

Figure: 2.9 (Field Picture 2014) OSP Fiber Optic cable across a bridge.

12

Figure: 2.10 (Field Picture 2014) Truss boring under existing road structure.

Unless inner ducts are installed in the HDPE, only one cable can be installed in the

HDPE unless all the cables are pulled together. Pulling a cable into a conduit which

already has several cables may cause tangling, increasing pulling tension and

potentially damaging cables. Inner duct or duct liners come in several types, including

flexible tubes with corrugated or smooth interiors; Smooth Interior is mostly used in

Ghana and most African countries. Corrugated tubes with smooth liners have a greater

tendency to flatten, limiting cable size, while corrugated interiors may be more fragile. A

new type of duct liner is more like a fabric sleeve that lies flat until the cable is pulled

through it, and takes up less space in the cable than rigid inner duct allowing space for

more cables to be installed and enhancing its security. (FOA 2014)

13

Figure: 2.11 (Field Picture 2014). This is a simple and less expensive technology used

to cross a storm drain.

As with any cable installation, it is important not to bend the cable too tightly this may

cause damage to the cable or its fibers. Standard cable guidelines are a minimal bend

radius of 20 times the cable diameter under tension and 10 times the cable diameter

after the pulling tension is removed.

2.4.3 Direct Buried/Buried CableIf the nature of the ground allows, fiber optic cables of the appropriate types can be

buried directly in the ground by plowing directly into the ground, directional boring or

trenching and placing the cable in the trench. Where the ground is soft and relatively

free of rocks and the land is flat and has no obstacles for the movement of heavy

equipment, direct burial is a fast method of installation, allowing several km of cables to

be installed in a day.

2.4.4 SUBMARINE/UNDERWATER CABLINGFiber optic cables sometimes need to be installed underwater. The best known of these

installations are probably the transoceanic cables that provide worldwide telecom and

Internet communications. Examples are May One, Sat 3 and Glo One cables, all these

cables runs from Africa to Europe. Installing these cables is a very specialized process

that requires special cable designs and custom cable-laying ships to pay out the cable

over thousands of kilometer runs and place it on the ocean floor at great depths

14

2.5 SAMPLE 1: THE USE OF WARNING TAPE TO PROVIDE FIBER SECURITY

Warning tapes forms an important part of the installation and helps prevent accidental

damage to the cables. To achieve fiber security the use of a warning tape is a

recommended option. A bright orange (preferably “ULCC” orange) warning tape with a

minimum width of 3 in (7.6 cm) may be buried approximately 12 in (30.5 cm) below the

existing grade. As a minimum, the tape should be marked “WARNING OPTICAL

CABLE.” This is done during the back-filling process. These underground marking tapes

are specified the world over as a warning system to protect against accidental dig-ins

and to alert workers of buried fiber cables. When dug up, the warning tape will stretch

up and out of the ground in one continuous piece alerting the operator to stop digging

immediately to avoid causing damage to the installed fiber infrastructure.

(http://www.reefindustries.com/communications-warning-tape.php)

Fig 2.12 Warning tape Fig. 2.12 (Field picture 2015) HDPE and Warning tape in

trench

2.5.1 Limitation of warning tape

As has been the case, these warning tapes which should have serve as security

measures for these Telcos, have not yielded the desired result. At times even the

warning tape is not placed at all and there is even an issue of literacy. Often people

employed to dig trenches for various purposes such as water supply and other

construction purposes sometimes are illiterate and either cannot read well or will not

15

even pay attention to writing on the warning tape. Below figure shows how the fiber is

still susceptible to cut although warning tapes have been installed.

Fig 2.13 Damage caused to fiber optic cable although there is a warning tape (2015)

2.5 SAMPLE 2: PROTECTING FIBER USING BRICKSAccording to Uranium Corporation of India Depth of trench shall be at least 750 mm in

soil. However, for road crossings/Concreted area the trench depth shall be at least 500

mm. The width of trench at the top and bottom shall be adequate for proper installation

of PLB HDPE pipes, GI pipes, Warning Brick etc. as per requirement. The trench depth

shall be measured from the bottom of the trench. Trench shall be located at the lowest

point of lower area if possible. Trench shall not be constructed at field boundary or any

up-heap. In case of uneven ground, the Contractor ensure that the bottom of the trench

is not uneven, the Contractor shall maintain minimum depth of the trench as per

specifications and may be required to increase the depth at some locations and provide

a suitable gradient in the trench. (Uranium Corporation of India 2014)

Bricks (non-modular) class designation-5(50) of the actual size 225 mm (Length) x 111

mm (Width) x 70 mm (Thick) shall be laid as per Figure - 1(average 17 bricks per meter)

immediately above and sides of the sand layer in which PLB HDPE pipe is installed.

Brick of size other than above may also be used. Warning bricks shall be used in

throughout the length (except road crossing and concreted are where GI pipe is to be

used). (Uranium Corporation of India Limited_2014)

16

Fig. 2.14 Laying Bricks in trenches to protect Fiber

2.5.2 Limitation of warning bricks

As can be seen from the picture above, protection of fiber in this way is not ideal since

the bricks can be destroyed by any indiscriminate digging leading to the cut of the fiber

cables by heavy road construction equipment. It is also possible for the disturbance in

the arrangement of bricks, should there be a major earth earthquake in areas where

earthquakes are prone to occur.

2.6 SAMPLE 3: USING FUTURE FIBER TECHNOLOGY LINK TO SECURE FIBER

FFT Secure Link can utilize the existing fiber optic communications cable as the sensor,

dramatically reducing the installation cost and time, yet still detect and intrusion to within

25 meters (75 feet) or better regardless of the size of the network. A single controller

can protect up to 40km (25 miles) of cable.

17

Laser light is transmitted along this fiber optic network cable, and the returned signal is

monitored and analyzed by the Secure Link controller for disturbances on the cable.

This returned signal is intelligently processed to minimize false alarms, while still

detecting and reacting to the smallest hostile event.

As can be seen in the picture below, there is no power or electronics installed in the

field. Power is only required at the sensing controller which is normally housed in a

secure control room. The inactive lead-in cable runs from the Secure Link controller to

the network cable where a start sensor is installed. The cable (shown in red) is now

sensitive all the way along the existing fiber bundle until the end sensor. (FFT Secure

Link).

Fig 2.15 Using Future Fiber Technology Secure Link to prevent Fiber cuts

2.6.1 Limitation of Using Future Fiber Technology Link to secure Fiber

Although Future Fiber Technology Secure Link system is used to detect intrusion on the

installed fiber network, experience shows that the fiber cables get cut any way before

the arrival of field team. The field team therefore restore the fiber to reduce downtime on

18

the network. As can be seen, it aids in the speedy restoration of the damaged fiber

infrastructure and not the prevention of the cable cuts.

2.7 SUMMARY OF LITERATURE REVIEW Judging from the works reviewed so far, we have concluded to improve upon the use of

the secure link sensor to prevent fiber cuts. We found out that, the secure link sensor

uses a pair of the free cores as means of deploying the link sensor mechanism. We

would therefore recommend the use a piezoelectric cable installed on the warning tape

at a depth of 0.4m from the top of the trench. This would be connected across the rings

created on the network. An emergency cable would also be installed at a depth of 1.1m

from the top of trench before final backfilling is done.

CHAPTER THREE

3.1 METHODOLOGYThis chapter presents the research methods used in the study. After a brief description

of what constitutes the study area, an overview of the research design is provided. A

19

description of the piezoelectric cable used as a Link sensor and procedure involved in

the design and the construction of its model showing how the various components and

subsystems relate with each other in the development of this system.

A piezoelectric sensor cable would be placed on top of the warning tape to prevent

accidental damage to the installed fiber. This sensor cable would detect an intrusion

and then send a signal to the Network Operating Center. The cable effectively behaves

as an extended microphone, converting stress, strain, vibration, impact, sound or

pressure change into minute electrical signals.

Fig 3.0 Piezoelectric sensor cable

20

Fig 3.1 Using a piezoelectric cable as a link sensor to prevent fiber optic cable cuts

Fig 3.2 General Block Diagram of the design concept

3.1.1 Description of Elements of Block DiagramMicrocontroller Unit –Arduino Uno. This is an electronic prototyping board based on

Atmega328P (an AVR 8-bit microcontroller). This will serve as the processing unit for

sensing and remote signaling.

Piezoelectric disc (sensors). This is for sensing vibrations or disturbances near the fiber

cables and thus detecting threats to it Sensor wire. This will be used for sensing when

the threat to the fiber cables are really critical requiring, emergency measures.

The LEDs are indicators indicating where which piezo disc is receiving vibrations or

disturbances. The buzzer is an alarm which sound to give a notification that there is an

emergency. The signal processor at the MCU sends a message to the computer

indicating where the disturbance has occurred. The PC shows an indication of where

the disturbance is located.

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3.2 DETAILED SCHEMATIC DIAGRAM

Fig 3.3 Schematic diagram of circuit

3.2.1 At the InputLS1, LS2 and LS3 (they are the piezo electric disc) and each of them is link to an

analogue pin. Each one of them will be at a particular segment where it will respond to

vibrations. Every segment of the fiber cable has a piezo electric disc sensor connected

to a microcontroller pin through a wire.

In the code, the threshold value is set to 400. This threshold correspond to a certain

kind of vibration which produce a certain kind of voltage. When it sense vibrations which

is above the threshold it will send a signal to the microcontroller unit (MCU).

When there is a disturbance at a particular segment, the piezo electric disc converts the

mechanical vibrations into an electrical voltage. This voltage is fed into the Analog Pin

of the microcontroller, which is configured as an Analog input. When the voltage sent to

the analogue pin it convert it to a variable and these values will be used to do the

processes by the microcontroller.

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On sensing the voltage from the Analog Pin the microcontroller compares the voltage to

a threshold voltage. This threshold voltage is there to ensure that common vibrations

are distinguished from vibrations that actually pose a threat to the cables.

When the microcontroller determines that the sensed voltage is greater than the

threshold voltage, it sends a signal to the control room through a dedicated fiber optic

cable.

3.2.2 At the OutputAt the output, we have light emitting diode (LED), a sensor cable and an alarm. There is

a code that runs in the microcontroller unit such that when there is a disturbance at any

of the terminal that is where the piezo electric disc is, the LED connected to that

particular disc will light. When the microcontroller determines that the sensed voltage is

greater than the threshold voltage, it sends a signal/voltage to a LED indicator switching

it on to indicate when and where the disturbance is occurring. The microcontroller also

sends a message to the computer indicating where and when the disturbance occurred

3.3 SPECIFICATIONSThe rating of the zener is 5.1v at which it become a closed circuit. When voltage range

between 0 to 5v, it allowed to get to the analogue pin but when it exceed 5v it would

have reached the threshold voltage of the zener diode hence voltage will be conducted

down to prevent excessive voltage from destroying the microcontroller unit (MCU).

The zener diode is configured in the reversed bias so that under normal circumstance,

no voltage will pass through it. It purpose is to protect the microcontroller unit

(MCU).The voltage released by the piezo will be proportional to the vibrations hence

high, which if not guard against can destroy the microcontroller unit (MCU).

The 1M ohm resistor is to prevent electromagnetic interference. Radiations can cause

the analogue pin to serve as an antenna that can receive these waves, so the voltages

will be induced into it. To prevent such voltages from affecting the true reading from the

piezo electric disc vibration, the analogue pin connected to the pull down resistor is

linked to ground. The pull down resistor sinks voltage to ground.

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The resistor connected to the LED at the output is to limit current that will pass through

the LED. This is because the LED has some internal resistance which when exceeded

will damage the LED. The resistor which is connected to the sensor wire is to prevent

too much current from damaging the microcontroller pin.

3.4 DESCRIPTION OF PINS CONNECTIONTable 3.1

PIN NUMBER FUNCTION

1 Transmit messages to computer

2 Controls light indicator for sensor A

3 Controls light indicator for sensor B

4 Controls light indicator for sensor C

14(Analog Pin A0) Sensors voltages transmitted by sensor A

15(Analog Pin A1) Sensors voltages transmitted by sensor B

16(Analog Pin A2) Sensors voltages transmitted by sensor C

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3.5 BACKGROUND OF COMPONENTS3.5.1 MICROCONTROLLER UNIT –ARDUINO UNO

Fig 3.4 Microcontroller Unit –Arduino Uno

Overview

The Arduino Uno is a microcontroller board based on the ATmega328. It has 14 digital

input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a

16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a

reset button. It contains everything needed to support the microcontroller; simply

connect it to a computer with a USB cable or power it with a AC-to-DC adapter or

battery to get started.

Power

The Arduino Uno can be powered via the USB connection or with an external power

supply.

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External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or

battery. The adapter can be connected by plugging a 2.1mm center-positive plug into

the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin

headers of the POWER connector.

The power pins are as follows:

VIN The input voltage to the Arduino board when it's using an external power source (as

opposed to 5 volts from the USB connection or other regulated power source). You can

supply voltage through this pin, or, if supplying voltage via the power jack, access it

through this pin.

5V.This pin outputs a regulated 5V from the regulator on the board. The board can

be supplied with power either from the DC power jack (7 - 12V), the USB connector

(5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins

bypasses the regulator, and can damage your board.

3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw

is 50 mA.

GND. Ground pins.

IOREF. This pin on the Arduino board provides the voltage reference with which the

microcontroller operates.

Communication

The Arduino Uno has a number of facilities for communicating with a computer, another

Arduino, or other microcontrollers. The ATmega328 provides UART TTL (5V) serial

communication, which is available on digital pins 0 (RX) and 1 (TX).

An ATmega16U2 on the board channels this serial communication over USB and

appears as a virtual com port to software on the computer. The '16U2 firmware uses the

standard USB COM drivers, and no external driver is needed. The Arduino software

includes a serial monitor which allows simple textual data to be sent to and from the

Arduino board.

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3.5.2 PIEZO ELECTRIC SENSOR

The piezoelectric sensor is a device that uses the piezoelectric effect to measure

charge in pressure, acceleration, temperature or force by converting them to an

electrical charge.

The high modulus of elasticity of many piezoelectric materials is comparable to that of

many metals and goes up to 106 N/m². Even though piezoelectric sensors are

electromechanical systems that react to compression, the sensing elements show

almost zero deflection. This gives piezoelectric sensors ruggedness, an extremely high

natural frequency and an excellent linearity over a wide amplitude range. Additionally,

piezoelectric technology is insensitive to electromagnetic fields and radiation, enabling

measurements under harsh conditions. Some materials used (especially gallium

phosphateor tourmaline) are extremely stable at high temperatures, enabling sensors to

have a working range of up to 1000 °C.

Two main groups of materials are used for piezoelectric sensors: piezoelectric ceramics

and single crystal materials. The ceramic materials (such as PZT ceramic) have a

piezoelectric constant/sensitivity that is roughly two orders of magnitude higher than

those of the natural single crystal materials and can be produced by

inexpensive sintering processes. The piezo effect in piezo ceramics is "trained", so their

high sensitivity degrades over time. This degradation is highly correlated with increased

temperature.

3.5.3 ZENER DIODE

The Zener Diode or “Breakdown Diode” is basically the same as the standard PN

junction diode but are specially designed to have a low pre-determined Reverse Breakdown Voltage that takes advantage of this high reverse voltage. The Zener

diode is the simplest types of voltage regulator and the point at which a zener diode

breaks down or conducts is called the “Zener Voltage”.

The Zener diode is like a general-purpose signal diode consisting of a silicon PN

junction. When biased in the forward direction it behaves just like a normal signal diode

passing the rated current, but as soon as a reverse voltage applied across the Zener

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diode exceeds the rated voltage of the device, the diodes breakdown voltage is reached

at which point a process called Avalanche Breakdown occurs in the semiconductor

depletion layer and a current starts to flow through the diode to limit this increase in

voltage.

The current now flowing through the Zener diode increases dramatically to the

maximum circuit value and once achieved this reverse saturation current remains fairly

constant over a wide range of applied voltages. The voltage point at which the voltage

across the zener diode becomes stable is called the “Zener voltage” for Zener diodes

this voltage can range from less than one volt to hundreds of volts.

Fig 3.5 Zener diode

3.5.4 LIGHT-EMITTING DIODE (LED)

A light-emitting diode (LED) is a semiconductor device that emits visible light when an

electric current passes through it. The light is not particularly bright, but in most LED is

monochromatic, occurring at a single wavelength. The output from an LED can range

from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400

nanometers).

An LED or consists of two elements of processed material called P-type semiconductors

and N-type semiconductors. These two elements are placed in direct contact, forming a

region called the P-N junction. In this respect, the LED resembles most other diode

types, but there are important differences. The LED has a transparent package,

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allowing visible. Also, the LED has a large PN-junction area whose shape is tailored to

the application.

Benefits Include

Low power requirement: Most types can be operated with battery power supplies.

High efficiency: Most of the power supplied to an LED is converted into radiation in the

desired form, with minimal heat production.

Long life: When properly installed, an LED can function for decades.

Fig 3.6 Blue, pure green, and red LEDs in 5 mm diffused cases

3.5.5 ResistorThe principal job of a resistor within an electrical or electronic circuit is to “resist”,

regulate or to set the flow of electrons (current) through them by using the type of

conductive material from which they are composed. Resistors can also be connected

together in various series and parallel combinations to form resistor networks which can

act as voltage droppers, voltage dividers or current limiters within a circuit.

Resistors are what are called “Passive Devices“, that is they contain no source of power

or amplification but only attenuate or reduce the voltage or current signal passing

through them. Resistors are often made out of chunk s of carbon or thin films of carbon

or other resistive materials. They can be made of wires wound around a cylinder. The

common resistor is a two wire package with a fixed resistance measured in ohms;

however, different types of resistors are adjustable by the circuit designer or the user.

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Also, most common type of resistor consists of a small ceramic (clay) tube covered

partially by a conducting carbon film. The composition of the carbon determines how

much current can pass through.

Resistors determine the flow of current in an electrical circuit. Where there is high

resistance in a circuit the flow of current is small, where the resistance is low the flow of

current is large.

Resistance, voltage and current are connected in an electrical circuit by Ohm’s Law.

When a resistor is introduced to a circuit the flow of current is reduced. The higher the

value of the resistor the smaller or lower the flow of current.

Resistors are marked with a number of coloured bands. Each colour stands for a

number. Three colour bands show the resistors value in ohms and the fourth shows

tolerance. Resistors are blind to the polarity in a circuit. Current can pass equally

through a resistor in either direction

Fig 3.7 Several different types of resistors

3.5.6 BUZZER ALARMBuzzer alarm is commonly used at the output for audio circuits. The buzzer alarm

convert electrical signal to sound energy.

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Fig 3.8 Buzzer alarm

CHAPTER FOUR

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4.0 CONSTRUCTION, TESTING, RESULTS AND ANALYSIS:

4.1 CONSTRUCTION:We arranged all the components and used jumping wires to connect them on the

solderless circuit board. We also checked to ensure that no leads touch each other.

A USB cable was connected between the Arduino Uno on the board to a PC to supply

the circuit with 5v.

Fig 4.1 Prototype of circuit on a board

Three Plastic conduit boxes with piezo disc fixed at the bottom of the conduit box were

placed were placed about 40 cm away from the circuit board in different direction. We

place the sensor wire place also about 50 cm away from the circuit board.

4.2 TESTINGTo test that the sensor wire was sensing the 5v supplied, the switch connected to the

sensor wire when switched on, causes the buzzer to sound indicating that the wire is no

longer sensing the 5v.

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To check the sensitivity of the piezo disc, the plastic conduit containing the piezo disc

was filled with sand to the brim. When force was applied by touching the sand, the LED

indicator connected to that particular piezo disc light.

We had to increase the threshold of the disc from 100 to 400 because the LED

indicators were lighting at a minimal touch.

4.3 RESULTS AND ANALYSISThis is the presentation of results of the entire circuit. A PC was connected to the

Arduino Uno on the circuit board via a USB cable. The PC is to display messages.

Fig 4.2 Simulation Capture

4.4 ANALYSISAs shown from the PC, the emergency message displayed indicates that the sensor

wire has been cut

The message showing a disturbance at A indicates that the piezo disc at that the said

location “A” is sensing vibrations which could pose a danger to the safety cable.

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The message showing a disturbance at B indicates that the piezo disc at that the said

location “B” is sensing vibrations which could pose a threat to the safety of the cable.

The message showing a disturbance at C indicates that the piezo disc at that the said

location “C” is sensing vibrations which could pose a threat to the safety of the cable in

that location.

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CHAPTER FIVE

5.0 CONCLUSION AND RECOMMENDATION

5.1 CONCLUSIONThe piezo disc were able to sense the vibrations and the corresponding voltages

transmitted to the microcontroller. To demonstrate that the system is functioning well,

the LED connected to the sensor where the vibration occurred light and a message is

displayed on the PC to indicate that there is a disturbance at the said location.

5.2 LIMITATIONOur main constraint was that the Arduino Nano we used could not function properly.

Hence we had to result to use the Arduino Uno which could only function on a

solderless PCB.

5.3 RECOMMENDATIONAn Arduino Nano should be used. This will allow the component to be soldered on the

PCB firmly.

Another alternative to the piezoelectric disc will be the piezoelectric cable. This will be

deployed in the field rather than the piezo electric disc to detect the disturbance. Since

the piezoelectric cable will be able to cover longer distances unlike the piezoelectric disc

which would have to be introduced every five meters which is avoided by the use of

piezoelectric cable.

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