i

ABSTRACT

Timing measurement is essential for sport (i.e. sprint event) and fitness test.

Conventionally, the measurement tool used is the stopwatch. However, the result obtained

from method of stopwatch is not consistent and not accurate due to reason of it involves

human manual element of starting and stopping the watch. Timing athlete with stopwatch

system has a typical error of around 7-10% to be expected. Therefore, an electronic timing

mechanism, also known as timing gate, is invented. Application of timing gate can provide a

more reliable and accurate measurement of speed and time during fitness testing instead of

using a stopwatch. In a timing gate system, a photoelectric sensor is used to create a light

beam, when athlete pass through the gate, the beam is broken or in other words, the light

beam is interrupted and the sensor will generate a signal which is then processed by the

computer. In our research, we are required to help a final year student to do the design in his

thesis about speed timing gate. Firstly, we need to identify the type of timing gate systems

which to be designed. Secondly, the type of sensor is chosen. Then, we proceed to designing

the mounting for the sensors. After that we assemble the system layout.

ii

ABSTRAK

Pengukuran masa adalah penting untuk sukan (contohnys acara pecut) dan ujian

kecergasan. Lazimnya, alat pengukuran yang digunakan ialah jam randik. Tetapi, hasil yang

diperolehi dariada penggunaan jam randik tidak konsisten dan tidak tepat kerana kaedah ini

melibatkan refleksi manusia untuk memulakan dan menghentikanjam randik. Pengukuran

masa dengan menggunakan kaedah jam randik mempunyai kesilapan sekitar 7-10%. Oleh itu,

satu mekanisme pemasaan elektronik, juga dikenali sebagai “timing gate” telah dicipta.

Pengguanan “timing gate” memberikan ukuran kelajuan dan masa yang lebih tepat semasa

ujian kecergasan dibandingkan denagn penggunaan jam randik. Dalam sistem “timing gate’

ini, sensor fotoelektrik digunakan untuk memancar satu alur cahaya, apabila atlet melalui

pintu gerbang, alur cahaya terganggu. Sensor itu akan menjana isyarat yang kemudiannya

akan diproses dalam komputer. Dalam kajian kami, kami dikehendaki untuk membantu

seorang pelajar tahun akhir untuk melakukan reka bentuk dalam tesisnya tentang “timing

gate”. Pertama, kita perlu mengenal pasti jenis sistem “timing gate” yang direka bentuk.

Kedua, jenis sensor dipilih. Kemudian, kita teruskan untuk mereka bentuk pelindung untuk

sensor. Selepas itu, kami merangkakan sistem tersebut secara tersusun.

iii

ACKNOWLEDGEMENT

I would like to express my sincere gratitude to the following people who have

contributed and assisted me throughout the entire research directly and indirectly.

Sincere thanks are due to my academic supervisor Mr. Ahmad Saifizul bin Abdullah for

his unmatched guidance, invaluable advice, and knowledge during the course of this project.

Thanks to senior, Hazman bin Hafiz for his advice and constructive suggestions on design of

timing gate systems.

An acknowledgement is also made to my department, Mechanical Engineering

Department, Engineering Faculty, University Malaya for offering this course KMEM 3173,

Integrated Design Project. Thanks are also due to my group members, Yip Pak Ngin

(KEM090062) and Julian Micky (KEM090064) for their invaluable suggestions on timing

gate design.

A mention must also be given to dealer in Technical Avenue Sdn. Bhd for giving us

some advice for selecting suitable sensor for our speed timing gate design.

I am also indebted to technical staffs, Mr. Dehis bin Mastik for utility and laboratory

supports.

Finally, thanks are due to my family and friends for their love, patience and

encouragement throughout many long days and nights of work. Not forgetting to my relatives

for their endless supports and encouragement during these difficult times.

iv

TABLE OF CONTENT

ABSTRACT ................................................................................................................................................. i

ABSTRAK ................................................................................................................................................. ii

ACKNOWLEDGEMENT ...................................................................................................................... iii

Table of content.................................................................................................................................... iv

List of Figure .......................................................................................................................................... vi

List of tables ........................................................................................................................................... ix

List of abbreviation ............................................................................................................................... x

CHAPTER 1 INTRODUCTION ........................................................................................................ 1

1.1 BACKGROUND ............................................................................................... 1

1.2 OBJECTIVE AND STUDY .............................................................................. 4

CHAPTER 2 Literature Study ........................................................................................................ 5

2.1 Timing devices .................................................................................................. 5

2.2 Reaction time ..................................................................................................... 7

2.3 Sensors ............................................................................................................... 7

2.4 Software ........................................................................................................... 20

v

2.5 What Is Data Acquisition? .............................................................................. 23

2.6 What is Illuminance? ....................................................................................... 27

CHAPTER 3 METHODOLOGY ...................................................................................................... 29

3.1 BENCHMARKING ........................................................................................ 29

3.2 Concept generation .......................................................................................... 41

3.3 concept selection ............................................................................................. 44

3.4 materials .......................................................................................................... 45

3.5 fabricating ........................................................................................................ 49

3.6 Cost .................................................................................................................. 54

CHAPTER 4 RESULT AND DISCUSSION .................................................................................. 55

4.1 System layout .................................................................................................. 55

4.2 Product Specification ...................................................................................... 57

4.3 DISCUSSIONS ............................................................................................... 65

CHAPTER 5 CONCLUSION AND RECOMMENDATION ...................................................... 69

5.1 Conclusion ....................................................................................................... 69

5.2 Recommendation ............................................................................................. 69

CHAPTER 6 REFERENCES ............................................................................................................ 72

vi

LIST OF FIGURE

Figure 2-1 Through Beam Sensor .................................................................................... 14

Figure 2-2 Retroreflective Sensor .................................................................................... 15

Figure 2-3 Diffuse Sensor ................................................................................................ 19

Figure 2-4 Data originates in the acquisition function and then flows intuitively to the

analysis and storage functions through wires .......................................................... 22

Figure 2-5 The use of data acquisition in a typical industrial process ............................. 23

Figure 2-6 Model Name - NI USB 6008 Data Acquisition Hardware, suitable for

academic experiment setup ...................................................................................... 26

Figure 3-1 SMARTSPEED by Fusion Sport using single beam with Error Correction

Processing (ECP) ..................................................................................................... 30

Figure 3-2 SpeedLight by Swift Performance using double beam system ...................... 32

Figure 3-3 Typical Error of Measurement (TEM) for the two systems ........................... 33

Figure 3-4 Measure of reliability, Coefficient of Variation (CV%) .............................. 34

Figure 3-5 Through Beam Sensor .................................................................................... 37

Figure 3-6 Diffuse-reflective Sensor ............................................................................... 37

vii

Figure 3-7 Retroreflective Sensor .................................................................................... 37

Figure 3-8 Sub-problems for Speed timing gate .............................................................. 42

Figure 3-9Milling machine .............................................................................................. 50

Figure 3-10Metal Cutting Band Saw Machine ................................................................ 50

Figure 3-11 Cutting the aluminium tube using metal cutting band saw machine ........... 51

Figure 3-12 Drilling the tube using turret milling machine ............................................. 51

Figure 3-13 Mounting box for the sensor ........................................................................ 52

Figure 3-14 Drilling process for mounting box of sensor................................................ 52

Figure 3-15 Drilling process for mounting box of sensor with the aid from lab assistant

.................................................................................................................................. 53

Figure 3-16 Surface finishing for mounting box of sensor .............................................. 53

Figure 3-17 Sawing process for bracket of mounting box of sensor ............................... 53

Figure 4-1 System Layout ................................................................................................ 55

Figure 4-2 Schematic diagram for the system layout ...................................................... 56

Figure 4-3 Sections in the system layout ......................................................................... 57

Figure 4-4 Schematic diagram for the system layout ...................................................... 58

viii

Figure 4-6 Dimension of sensorFigure4-7 Hardware Figure 4-5 Components of the

system ...................................................................................................................... 59

Figure 4-8 Dimension of the reflector ............................................................................. 59

Figure 4-9 Mounting for sensors...................................................................................... 60

Figure 4-10 Mounting for Reflector ................................................................................ 60

Figure 4-11 Mounting for sensor ..................................................................................... 60

Figure 4-12 Trajectory View of the mounting rack for the sensor ................................... 61

Figure 4-13 Mounting Rack for Reflector ....................................................................... 61

Figure 4-14 Trajectory view of the mounting rack for the reflector ................................ 62

Figure 4-15 Camera Tripod Stand ................................................................................... 62

Figure 4-16 Sample CAD model of a Tripod Stand ........................................................ 62

Figure 4-17 Sample Front Panel for the User Interface ................................................... 64

Figure 4-18 Poorly designed multiple beam gate system ................................................ 67

ix

LIST OF TABLES

Table 2-1 Phenomena and Existing Transducers ............................................................. 24

Table 2-2 General information about USB 6008 ............................................................. 27

Table 2-3 Illuminance for a Few Examples ..................................................................... 28

Table 3-1 Comparison among the Through Beam, Diffuse-reflective and Retro reflective

Photoelectric sensors ................................................................................................ 37

Table 3-2 Comparison of OMRON E3FZ-R and TELCO SPACEPARK SPPR ............ 39

Table 3-3 Mechanical properties of ABS ........................................................................ 46

Table 3-4 Physical properties of ABS ............................................................................. 46

Table 3-5 Physical properties of Aluminium Alloy 6061 ................................................ 47

Table 3-6 Thermal properties of Alumimium Alloy 6061 ............................................... 47

Table 3-7 Electrical Properties of Aluminium Alloy 6061 .............................................. 47

Table 3-8 Mechanical properties of 304 grade stainless steel ......................................... 48

Table 3-9 Physical properties of 304 grade stainless steel .............................................. 48

Table 3-10 Cost Estimation for the Speed Timing Gate System ..................................... 54

x

LIST OF ABBREVIATION

% Percentage

Mr. Mister

Sdn.Bhd Private limited company

M Metre

Mm Milimetre

LED Light Emitting Diode

Hz Hertz

°F Degree of Fahrenheit

µ Micro (x10-6

)

sec Second

in. Inches

micron micrometre

DAQ Data Acquisition

i.e For example

NI National Instrument

USB Universal Serial Bus

RTD Resistance temperature detectors

LVDT Linear Variable Differential

Transformer

pH measure of the acidity or basicity

PC Computer

I/O Input/ Output

ECP Error Correction Processing

TC Test Center

Etc "and other things" or "and so on"

TEM Typical Error of Measurement

CV Coefficient of Variation

Wt Weightage

max Maximum

G gram

Cm centimeter

approx approximately

°C Degree of Celcius

G Giga(x109)

Pa Pascal

W watt

Ω Ohm

1

CHAPTER 1 INTRODUCTION

1.1 BACKGROUND

Sprints are the short running events in athletics and track field. Races over short distances are

among the oldest running competitions in the world. At the higher professional level, most of

the sprinters begin the race by assuming a crouching position in the starting blocks before

leaning forward and gradually moving into an upright position as the race progresses and

momentum is gained. The set position differs depending on the start. Body alignment is one

of key importance in producing the optimal amount of force. Athletes remain in the same lane

on the running track throughout all sprinting events, with the sole exception of the 400 m

indoors. Races up to 100 m are largely focused upon acceleration to an athlete's maximum

speed. All sprints beyond this distance increasingly incorporate an element of endurance.

Timing gates are very valuable tools for the exercise physiologist for timing

measurement during fitness testing. They are most widely used for sprint testing, though

many systems can be adapted for other applications such as measuring vertical jump height

and reaction time. Hence, it is also an instrument tool that can be used to measure for the

running per-formance in athletic development and research. There is a wide range of these

system has been developed with purposes for commercially or in-house usage.

2

There are several types of timing gates made specifically to measure running speed in

fitness testing. Compared to the alternative of using a stopwatch, the timing gate provides an

accurate and reliable measure of speed.

Using infra-red signal and detectors, the gates record when the beam is broken. Using

different configurations, the gates should be able to be used for single sprint, repeat sprints,

running back and forth through same gate, and multiple people sprinting in different lanes.

Some systems may also come with a timing switch sensor mat to use for vertical jump testing.

Generally, a single retroreflective beam timing light existing in global market used to

register a signal when an athlete passes the timing gate. However, this type of system has

been critised for introducing errors due to false signal registered. The main objective of the

timing gate specifically is to measure the speed of movement of an athlete as accurate as

possible, so we can identify athlete’s performance even it is a small improvement or

deterioration Australian Institute of Sport has conducted a research shown that single beam

timing light has a typical error of range over 5%. Hence, the system is not accepted by

Australian Institute of Sport Network and cannot be purchased in Australia.

A single beam system produce an undesirable error as an athlete passes through the

photo beam hence “break” the beam and it will register a signal. A few breaks can occur due

to leading or trailing hands or feet and the torso. Single beam system will trigger a signal by

the first event or in other words when the first time “the beam has been broken” at start and

3

stop or split gates. The source of unreliability of this system is, for example, the start gate

may be triggered by hand or feet instead of the torso, hence the results obtained is not an

accurate result. In running, the start or stop time will be determined only when the body or

torso of the athlete passes the starting ending line.

Generally, there are five common features of Athletic/ Sport Timing Gate:

Storage, Process & Download – large amount of data needs to be recorded during field

track event. Therefore, capability of the system to store, download and process the signal

are very essential since it is one of the purposes timing gate is being implement for track

field use.

Single or multiple beam – depends of the types of the system. A single beam system is

easy to setup and align but comes with poor results whilst multiple beams can overcome

false signal being triggered by leading hand or trailing foot but more difficult to set up as

all beams must be aligned for it to work.

Wiring – wireless or wired systems. Wireless system enables timing gates to be placed

anywhere within the coverage range and it is very easy to setup and disassemble since no

wiring required to operate. Wireless system reduced possibility of someone get tripped by

the running wire on the ground. But somehow wired system comes with lower price

compared to the wireless one.

Ease of Setup – the easier the setup is, the better it gets. Time for setup and number of

people required to do the setup can be reduced if the system has easy installation process.

4

Reliability – the system must be reliable and produce accurate result every time it is

working. Poor or inconsistent result from the timing gate system can be misinterpreted as

the athlete performance has improved or deteriorated.

Environmental Condition – since it is outdoor instrument tools, it must be durable,

portable, water resistant and works well in every situation whether rain, heat or cold.

Furthermore the timing gate must have good stability and balanced too during windy

condition.

1.2 OBJECTIVE AND STUDY

To develop a speed timing gate system

To design the hardware component for the speed timing gate system

5

CHAPTER 2 LITERATURE STUDY

2.1 TIMING DEVICES

Hand-held stopwatches have become more accurate, but they depend on human judgement

and reactions. This places an absolute limit on accuracy – times will be uncertain by at least

0.2 of a second. Over a 100 metres foot-race this is equal to an error of 2 metres.

Such inaccuracy presents considerable difficulties. For example, in the 1960 Olympic

Games in Rome, Australia's John Devitt and America's Lance Larson finished neck-and-neck

in the final of the 100 metres freestyle swimming event. Two of the three first-place judges

had Devitt as the winner, but two of the three second-place judges had Devitt second. Among

the timekeepers there was no doubt: all three on Devitt's lane gave him 55.2 seconds, while

the timekeepers on Larson's lane gave him 55.0, 55.1 and 55.1 seconds – all faster than Devitt.

But all six measurements were within 0.2 of a second of each other; thus, they did little

to help decide the winner. On the basis of the decisions by the first-place judges, the race was

awarded to Devitt and the official time for both was recorded as 55.2 seconds. John Devitt

received the gold medal.

6

In 1964 an electronic quartz timing system was used for the first time in international

events, thereby improving timing accuracy to 0.01 of a second. The computerised timing

systems used in events today have increased the accuracy to less than 0.001 of a second,

which is 10 times the accuracy required under the rules.

Judging very close running races remained a problem until photo-finish video cameras

were used at the finish line. (Originally, film-based cameras were used, but this meant that

athletes and spectators had to wait until the film was developed before they knew the result.)

The introduction of the vertical line-scanning video system in 1991 totally removed human

judgement and reactions from the timing and judging of world class running events. The

starter's pistol is linked to a transducer, which detects the sound made when the starter pulls

the trigger. The transducer is connected to a timing computer, which starts to count

immediately it receives the signal.

Connected into this system is a high quality video camera located at the finish line. This

produces the official time and a video image of the athletes as each one passes the finish line.

The video camera scans a thin line aligned with the finish line up to 3000 times per second.

The video image of each athlete as they actually cross the line is shown superimposed with a

grid that records the time for each competitor. This system allows judges to declare the result

more quickly and more accurately. (Two parallel infra-red beams also located at the finish

line are directly linked to display boards within the stadium. They provide the audience with

an instant but unofficial time for the race.)

7

2.2 REACTION TIME

Reaction time is the time that elapses between the moment a stimulus is detected by the brain

and the moment a response starts. Tests have confirmed that nobody can react in less than

0.110 of a second. Sprinters need excellent reactions to ensure that they leave the blocks as

quickly as possible after hearing the gun. Australia's Cathy Freeman, a world-class athlete,

had a reaction time of 0.223 seconds in the 1995 World Championships women's 400 metres

final.

A device within each starting block records the interval between the gun firing and the

first athlete leaving the blocks. A false start is declared if this interval is less than 0.110 of a

second, since the runner must have decided to go before hearing the gun.

2.3 SENSORS

Photoelectric sensors represent perhaps the largest variety of problem solving choices in the

industrial sensor market. Today ’s photoelectric technology has advanced to the point where

it is common to find a sensor that will detect a target less than 1 mm in diameter while other

units have a sensing range up to 60 m. These factors make them extremely adaptable in an

endless array of applications. Although many configurations are available including laser-

8

based and fibre optic sensors, all photoelectric sensors consist of a few of basic components.

Each contains an emitter, which is a light source such as an LED (light emitting diode) or

laser diode, a photodiode or phototransistor receiver to detect the light source, as well as the

supporting electronics designed to amplify the signal relayed from the receiver.

Probably the easiest way to describe the photoelectric operating principal is: the emitter,

also referred to as the sender, transmits a beam of light either visible or infrared, which in

some fashion is directed to and detected by the receiver. Although many housings and

designs are available they all seem to default to the basic operating principal.

Just as the basic operating principal is the same for all photoelectric families, so is

identifying their output. “Dark-On” and “Light-On” refers to output of the sensor in relation

to when the light source is hitting the receiver. If an output is present while no light is

received, this would be called a “Dark On” output. In reverse, if the output is ON while the

receiver is detecting the light from the emitter, the sensor would have a “Light-On” output.

Either way, a Light On or Dark On output needs to be selected prior to purchasing the sensor

unless it is user adjustable. In this case it can be decided upon during installation by either

flipping a switch or wiring the sensor accordingly.

The method in which light is emitted and delivered to the receiver is the way to

categorize the different photoelectric configurations. The most reliable style of photoelectric

sensing is the through beam sensor. This technology separates the emitter and receiver into

9

separate housings. The emitter provides a constant beam of light to the receiver and detection

occurs when an object passing between the two breaks the beam. Even though it is usually

the most reliable, it often is the least popular due to installation difficulties and cost. This is

because two separate pieces (the emitter and receiver) must be purchased, wired and installed.

Difficulties often arise in the installation and alignment of two pieces in two opposing

locations, which may be quite a distance apart.

Through beam photoelectric sensors typically offer the longest sensing distance of

photoelectric sensors. For example, units are available with a 25 m and more sensing range.

Long range is especially common on newly developed photoelectric sensors such as models

containing a laser diode as the emitter. Laser diodes are used to increase sensing accuracy and

detect smaller objects. These units are capable of transmitting a well-collimated beam with

little diffusion over the sensing ranges as long as 60 m. Even over these long distances, some

through beam laser sensors are capable of detecting an object 3 mm in diameter, while

objects as small as 0.01 mm can be sensed at closer ranges. However, while precision

increases with laser sensors the speed of response for laser and non-laser through beam

sensors typically remain the same, around 500 Hz. An added bonus to through beam

photoelectric sensors is their ability to effectively sense an object in the presence of a

reasonable amount of airborne contaminants such as dirt. Yet if contaminants start to build up

directly on the emitter or receiver, the sensor does exhibit a higher probability of false

triggering. To prevent false triggering from build-up on the sensor face, some manufacturers

incorporate an alarm output into the sensor’s circuitry. This feature monitors the amount of

light arriving on the receiver. If the amount light decreases to a certain level without a target

in place, the sensor sends a warning out by means of a built in LED and/or an output wire.

10

A very familiar application of a through beam photoelectric sensor can be found is right

in your home. Quite often, a garage door opener has a through beam photoelectric sensor

mounted near the floor, across the width of the door. This sensor is making sure nothing is in

the path of the door when it is closing. A more industrial application for a through beam

photoelectric is detecting objects on a conveyor. An object will be detected anyplace on a

conveyor running between the emitter and receiver as long as there is a gap between the

objects and the sensors light does not “burn through ” the object. This is more a figurative

term than literal. It refers to an object that is thin or light in colour and allows the light

emitted from the emitter to penetrate the target so the receiver never detects the object.

The photoelectric family with the next longest sensing distance is called retro-reflective

sensors, commonly referred to as a “retro”. Retro--reflective sensors operate similarly to

through-beams without being able to reach the same sensing distances. Certain units may still

be used in applications needing ranges of up to 10 m. The similarity between retro-reflective

and beam photoelectric sensors is that there is a constant beam that needs to be broken in

order for an output to occur. But, instead of having a separate housing for the emitter and

receiver, they are both located in the same housing, facing the same general direction. The

emitter produces a laser, infrared or visible light and projects the beam towards a specially

designed reflector, which returns the beam, back to the receiver. .Detection occurs when the

light path is broken or otherwise interfered with. If the output occurs when the beam is

broken, the sensor would be considered a dark-on photo.

11

A reason one would specify a retro-reflective sensor over a through beam is because

only one location needs to be wired for installation. The opposing side simply requires

installation of the reflector. This could result in a big cost savings in both parts and time.

However, objects that are very shiny or highly reflective like a mirror, a can, or small

juice box wrapped in clear plastic can provide a challenge to a retro-reflective photoelectric.

These targets may reflect enough light to “trick” the sensor: because ample light is reflected

from the object, the receiver may not recognize that the beam has been interrupted and the

sensor does not identify that the target has passed. Some manufacturers have addressed this

problem with a polarization filter, which allows only light reflected a specially designed

reflector to be received, and not erroneous reflections from the target.

Diffuse-reflective sensors operate under a somewhat different style than retroreflective

sensor and through-beams although the operating principle remains the same: diffuse

reflective sensors actually use the target as the “reflector”, such that detection occurs upon

reflection of the light off the object back onto the receiver as opposed to an interruption of the

beam. The emitter sends out a beam of light. Most often it is a pulsed infrared, visible red or

laser beam, which is reflected by the target when it enters the detectable area. The beam is

diffused off of the target in all directions. Part of the beam will actually return back to the

receiver inside of the same housing in which the sensor originally emitted it from. Detection

occurs and the output will either turn on or off (depending upon if it is Light On or Dark On)

when sufficient light is reflected to the receiver. This can be commonly witnessed in airport

washrooms, where a diffuse photo will detect your hands as they are placed under the faucet

12

and the attending output will turn the water on. In this application, your hands act as the

reflector.

Due to the operating principle of using the target as the reflector, diffuse reflective

sensors are often at the mercy of target material and surface properties; a non-reflective target

such as matte-black paper will have a significantly decreased sensing range as compared to a

bright white target. But, what seems as a drawback on the surface can actually be a benefit in

practice. Because diffuse sensors are somewhat color dependant, certain versions are suitable

for distinguishing dark and light targets in applications that require sorting by contrast or

quality control. Specialty versions of diffuse sensors are even capable of detecting different

colours. Also, with only the sensor itself to mount, installation of diffuse sensors is usually

simpler than for through-beams and retroreflective.

Deviations of sensing distances and false triggers when reflective backgrounds are

present led to the development of other diffuse sensors. These new developments, allow the

diffuse sensor to “see” an object while simultaneously ignoring any objects behind it. In the

simplest of terms, the sensor is looking out at specific point in the foreground and ignoring

anything beyond that point. There are two ways in which this function is achieved, the first

and most common is using fixed-field technology. In this technology, the emitter sends out a

beam of light like a standard diffuse photoelectric sensor. In turn, the light is received by two

receivers and a comparator then evaluates how the light is received. One receiver is focused

on the “sweet spot” or desired sensing location and the other on the background or long range.

If the comparator finds the long-range receiver is detecting a higher intensity of reflected

13

light, than the amount on the focused receiver, the output will not turn on. Only when the

intensity of light on the focused receiver is above the long-range receiver will an output occur.

Adjustable sensing distance versions are also available. The receiver element in an

adjustable-field sensor is accomplished by the use of an array of receivers and a

potentiometer to electrically adjust the sensing distance.

Fixed-field and adjustable-field photoelectric sensors operate optimally at their preset

“sweet spot”. They allow for the recognition of small parts and a tight drop-off between the

sensed target and cut-off point. They also offer an improvement over a standard diffuse

sensors’ difficulty in sensing different colour targets. However, target material surface

qualities, such a high gloss, can produce various results. In addition, highly reflective objects

outside of the sensing area tend to send enough light intensity back to the receivers for the

output to trigger, especially when the receivers are electrically adjusted.

To combat these limitations, a technology known commonly as true background

suppression by triangulation was developed. True background suppression sensors emit a

beam of light exactly like a standard diffuse, but unlike fixed-field sensors, which rely on

light intensity, background suppression units rely completely on the angle at which the beam

returns to the sensor.

14

To accomplish this, background suppression sensors employ two or more receivers

accompanied by a focusing lens. The receivers remain in a fixed position, while the lens is

mechanically adjusted to change the angle of received light. .This configuration allows for an

extremely steep cut off between target and background, sometimes as small as 0.1 mm. Also,

this is a more stable method when reflective backgrounds are present, or large target colour

variations are an issue: reflectivity and colour affect the intensity of reflected light, not the

angles of refraction used by triangulation-based background suppression photos.

Figure 2-1 Through Beam Sensor

The transmitter and receiver in a thru-beam application are in separate housings

mounted opposite each other. The transmitter emits pulsed light in the infrared or visible red

wavelength range. The receiver detects the light beam and immediately converts a beam

interruption caused by an object in the sensing zone into a switched signal.

Thru-beam pairs are typically used where long sensing ranges or high excess gain (the

additional light energy that is emitted to overcome dust, water, or oil that may build up on the

lens of a photoelectric device) is required. The effective beam describes the area that must be

completely interrupted to reliably sense a target. The diameter of the effective beam, or beam

15

diameter, is used to predict how well a sensor will detect small objects, and it is generally

based on the size of the optical lens.

The output of a thru-beam pair can be configured to provide a signal when a target

interrupts the beam (“dark-on” or “dark-operate”) or when a target is not present (“light-on”

or “light-operate”). Care must be taken to avoid cross-talk when using multiple thru-beam

pairs. Cross-talk occurs when the light emitted from one transmitter is detected by a receiver

other than the intended one.

Figure 2-2 Retroreflective Sensor

Unlike an through beam sensor, a retroreflective sensor contains both the emitter and

receiver elements. The effective beam is established between the emitter, the reflector, and

the receiver. As with an opposed-mode sensor, an object is sensed when it interrupts or

"breaks" the effective beam. Most reflectors are made up of many small corner-cube prisms.

A light beam enters a corner cube prism through its hypotenuse face and is reflected from the

three surfaces. In this way, the reflector returns the light beam to its source. Most corner-cube

reflectors resemble bicycle reflectors, and are moulded using clear acrylic plastic,

manufactured in various sizes, shapes, and colours. If an opposed-mode sensor is not an

option, then a retro reflective-mode sensor may be a good second choice. Retroreflective

16

mode sensors offer relatively long ranges. Retroreflective sensing is a beam-break mode. So,

it is generally not dependent upon the reflectivity of the object to be detected. For this reason,

the retroreflective mode is a relatively reliable sensing mode.

A retroreflective-mode sensor offers a convenient alternative to opposed mode when

sensing is possible only from one side, or if electrical connections are only possible on one

side. Retroreflective-mode sensors lose excess gain twice as fast as opposed-mode sensors,

due to dirt build-up on both the reflector and the sensor lenses. This is because the light

travels through four lenses, once from the emitter to the reflector and back from the reflector

to the receiver. There is also much less available excess gain in a retroreflective mode sensing

beam, due to the inefficiencies of the reflector and because the light must travel twice as far

to reach the receiver, as compared to the opposed mode. It's difficult to create a small

effective beam with a retroreflective mode sensor, so avoid using this mode for detecting

small objects or for precise positioning control. We can offer some retroreflective sensors that

have an effective beam of less than 25mm. The optics of a good quality retroreflective sensor

are designed and assembled with great care to minimize "proxing" (undesirable reflection of

the sensing beam directly back from an object that is supposed to break the beam). However,

an object with a shiny surface that presents itself perfectly parallel to a retroreflective sensor

may return enough light to cause that object to pass by the sensor, undetected. This problem

can be compensated for by angling the sensor relative to the object to avoid direct reflection

or by using an anti-glare or polarizing filter.

17

Except at close range, the size of the reflector becomes important. The width of the

beam pattern for each retroreflective sensor serves as an estimate of how much reflector area

should be used to return the maximum amount of light. Reflector size does affect the range.

The smaller the target size, the smaller the effective beam, and the shorter the range.

Also the efficiency of different reflector material types varies. Most retroreflective

sensors are designed for long-range sensing, and suffer a "blind spot" at close range. A "Blind

Spot" is an area close to a sensor lens, where light energy is returned to the emitter rather than

the receiver, rendering the sensor effectively blind. This effect is most pronounced with some

retroreflective sensors. A retroreflective sensor contains both the emitter and receiver element.

The effective beam is established when the emitter sends a light beam which is bounced off a

reflector, back to the emitter. An object is detected when it breaks this effective beam.

Retroreflective-mode sensors offer reliability, and are convenient in applications where

sensors can be mounted only on one side of a process. However, retroreflective sensors can

lose gain twice as fast as opposed mode sensors, and they aren't always the best choice for

sensing shiny, clear, or very small objects

A Proximity sensor can detect objects without physical contact. A proximity sensor

often emits an electromagnetic field or beam and look for changes in the field. The object

being sensed is often referred to as the proximity sensor's target. Different proximity sensor

targets demand different sensors. For example, a capacitive or photoelectric sensor might be

suitable for a plastic target; an inductive proximity sensor requires a metal target. In

capacitive proximity sensors, the sensed object changes the dielectric constant between two

18

plates. A proximity sensor has a range, which is usually quoted relative to water. Because

changes in capacitance take a relatively long time to detect, the upper switching range of a

proximity sensor is about 50 Hz. The proximity sensor is often found in bulk-handling

machines, level detectors, and package detection. One advantage of capacitive proximity

sensors is that they are unaffected by dust or opaque containers, allowing them to replace

optical devices. A typical capacitive proximity sensor has a 10-mm sensing range and is 30

mm in diameter. The proximity sensor incorporates a potentiometer to allow fine tuning of

the sensing range and can repetitively detect objects within 0.01 mm of the set point.

Switching frequency is 10 Hz, and operating temperature range is -14 to 158°F. Conditioning

the output of a proximity sensor has always been difficult. Proximity sensor designers must

confront linearity, hysteresis, excitation voltage instability, and voltage offset. A proximity

sensor that measures current flow between the sensing electrode and the target provides

readouts in appropriate engineering units. Usually, one side of the voltage source or oscillator

connects to the sensing electrode, and the other side connects through a current-measuring

circuit to the target, which generally is a metal part at earth or ground potential. Probes used

with a capacitive proximity sensor have either a flat disc or rectangular sensing element

surrounded by a guard electrode that provides electrical isolation between the proximity

sensor and its housing. The guard also ensures that the lines of electrostatic field emanating

from the probe are parallel and perpendicular to the surface of the proximity sensor.

Capacitance proximity sensor systems can make measurements in 100 µsec with resolutions

to 10-7

in. (0.001 micron). Probe diameters range from a few thousandths of an inch to several

feet for corresponding measurements ranging from thousandths of an inch to several feet.

19

Diffuse sensors operate similarly to the retroreflective sensors in that the transmitter and

receiver are contained in a single housing. However, diffuse sensors rely on transmitted light

being reflected back by the target to determine output status. The sensitivity of a diffuse

reflective sensor is very high. Only 2% of the transmitted light must be reflected back by the

target to switch the output. As opposed to thru-beam and retroreflective applications, a

diffuse application is considered “light-operate” when a target interrupts the beam and “dark-

operate” when the target is not present. Diffuse sensors are used for short sensing ranges. The

term “light spot” refers to the area in which the target can be accurately sensed. The size of

the light spot can be determined based on the angle of aperture (αt) of the transmitted beam

using the following formula:

Figure 2-3 Diffuse Sensor

Since the sensor evaluates the direct reflection of light by the target, detection depends

on the reflective qualities of the target, i.e., size, texture, shape, and colour. The more

reflective the target, the easier it is to detect with a diffuse sensor.

In a diffuse reflection application, one must also consider the background behind the

target. If the sensor is set to maximum sensitivity and an object other than the target is within

the range of the sensor, that object will cause the output to switch even though the target may

tan αt= light spot diameter / (2 x sensing distance)

20

not be present. For this case, the sensitivity must be reduced through the use of a “teach”

button or potentiometer adjustment.

2.4 SOFTWARE

2.4.1 NATIONAL INSTRUMENTS LabVIEW

LabVIEW is a graphical programming environment used to develop sophisticated

measurement, test, and control systems using intuitive graphical icons and wires that

resemble a flowchart. It offers unrivalled integration with thousands of hardware devices and

provides hundreds of built-in libraries for advanced analysis and data visualization – all for

creating virtual instrumentation.

LabVIEW: Graphical, Dataflow Programming

LabVIEW is different from most other general-purpose programming languages in two

major ways. First, G programming is performed by wiring together graphical icons on a

diagram, which is then compiled directly to machine code so the computer processors can

execute it. While represented graphically instead of with text, G contains the same

programming concepts found in most traditional languages. For example, G includes all the

standard constructs, such as data types, loops, event handling, variables, recursion, and

object-oriented programming.

The second main differentiator is that G code developed with LabVIEW executes

according to the rules of data flow instead of the more traditional procedural approach (in

21

other words, a sequential series of commands to be carried out) found in most text-based

programming languages like C and C++. A Dataflow language like G promotes data as the

main concept behind any program. Dataflow execution is data-driven, or data-dependent. The

flow of data between nodes in the program, not sequential lines of text, determines the

executionorder.

This distinction may seem minor at first, but the impact is extraordinary because it

renders the data paths between parts of the program to be the developer’s main focus. Nodes

in a LabVIEW program (in other words, functions, structures such as loops, subroutines, and

so on) have inputs, process data, and produce outputs. Once all of a given node’s inputs

contain valid data, that node executes its logic, produces output data, and passes that data to

the next node in the dataflow path. A node that receives data from another node can execute

only after the other node completes execution.

Benefits of G Programming

G code is typically easier for engineers and scientists to quickly understand because they

are largely familiar with visualizing and even diagrammatically modelling processes and

tasks in terms of block diagrams and flowcharts (which also follow the rules of data flow). In

addition, because dataflow languages require you to base the structure of the program around

the flow of data, you are encouraged to think in terms of the problem you need to solve. For

example, a typical G program might first acquire several channels of temperature data, then

pass the data to an analysis function, and, finally, write the analyzed data to disk. Overall, the

flow of data and steps involved in this program are easy to understand within a LabVIEW

diagram.

22

Figure 2-4 Data originates in the acquisition function and then flows intuitively to the analysis and

storage functions through wires

A Better Way to Solve Problems

LabVIEW and its graphical, dataflow programming language provides a better way to

solve problems than traditional, lower-level alternatives, and the proof is in its longevity. The

key differentiators for programming in G are the intuitive graphical code that can create and

the data-driven rules that govern its execution combine to offer a programming experience

that expresses the thought processes of its users more closely than other languages.

23

2.5 WHAT IS DATA ACQUISITION?

Data acquisition (DAQ) is the process of measuring an electrical or physical

phenomenon such as voltage, current, temperature, pressure, or sound. By using a standard

laptop or desktop PC, it can be turn into user-defined measurement or control system with

combination of modular hardware i.e NI USB 6008 and flexible software, for example

LabVIEW.

Figure 2-5 The use of data acquisition in a typical industrial process

While each data acquisition system has unique functionality to serve application-

specific requirements, all systems share common components that include signals, sensors,

signal conditioning, DAQ hardware, and a computer with software.

24

2.5.1 Signals/Sensors

A sensor (or transducer) is a device that converts a physical phenomenon into a

measurable electrical signal, such as voltage or current. The following table shows a short list

of some common phenomena and the transducers used to measure them.

Table 2-1 Phenomena and Existing Transducers

Phenomenon Transducer

Temperature Thermocouple, RTD, Thermistor

Light Photo Sensor

Sound Microphone

Force and Pressure Strain Gage, Piezoelectric

Transducer

Position and Displacement Potentiometer, LVDT, Optical

Encoder

Acceleration Accelerometer

pH pH Electrode

Transducers convert physical phenomena into measurable signals; however, different

signals need to be measured in different ways. For this reason, it is important to understand

the different types of signals and their corresponding attributes. Signals can be categorized

into two groups: analog and digital.

2.5.2 DAQ Hardware

Data acquisition hardware acts as the interface between a computer and signals from the

outside world. It primarily functions as a device that digitizes incoming analog signals so that

the computer can interpret them.

25

Connection to Signals

Data acquisitions devices typically consist of one or more of the following functions for

measuring different types of signals:

Analog inputs – measure analog signals

Analog outputs – generate analog signals

Digital inputs/outputs – measure and generate digital signals

Counter/timers – count events or generate pulses

Multifunction data acquisition boards combine analog, digital, and counter operations on

a single device. Additionally, some data acquisition boards include integrated signal

conditioning specific to a signal or sensor type.

2.5.3 Advantages of NI DAQ

Designed for performance, NI data acquisition devices provide high-performance I/O,

industry-leading technologies, and software-driven productivity gains for your application.

With patented hardware and software technologies, National Instruments offers a wide-

spectrum of PC-based measurement and control solutions that deliver the flexibility and

performance that your application demands.

High-Performance I/O

Measurement accuracy is arguably one of the most important considerations in

designing any data acquisition application. Yet equally important is the overall performance

of the system, including I/O sampling rates, throughput, and latency. For most engineers and

26

scientists, sacrificing accuracy for throughput performance or sampling rate for resolution is

not an option. National Instruments wide selection of PC-based data acquisition devices has

set the standard for accuracy, performance, and ease-of-use.

2.5.4 NI USB 6008

In this project, we are using NI USB-6008 as our data acquisition instrument. The

National Instruments USB-6008 provides basic data acquisition functionality for applications

such as simple data logging, portable measurements, and academic experiments. It is low-

cost and affordable for student research and development project, but powerful enough for

more sophisticated measurement applications.

Figure 2-6 Model Name - NI USB 6008 Data Acquisition Hardware, suitable for academic

experiment setup

27

Table 2-2 General information about USB 6008

Product Name USB-6008

Product Family Multifunction Data Acquisition

Form Factor USB

Part Number 779051-01

Operating System/Target Linux , Mac OS , Pocket PC , Windows

DAQ Product Family B Series

Measurement Type Voltage

RoHS Compliant Yes

2.6 WHAT IS ILLUMINANCE?

In the research for the sensors, we came across with a term “illuminance”. What is

illuminance?

Illuminance is a measure of how much luminous flux is spread over a given area. One

can think of luminous flux (measured in lumens) as a measure of the total "amount" of visible

light present, and the illuminance as a measure of the intensity of illumination on a surface. A

given amount of light will illuminate a surface more dimly if it is spread over a larger area, so

illuminance is inversely proportional to area.

One lux is equal to one lumen per square metre:

1 lx = 1 lm/m2 = 1 cd·sr·m

–2.

28

A flux of 1,000 lumens, concentrated into an area of one square metre, lights up that

square metre with an illuminance of 1,000 lux. However, the same 1,000 lumens, spread out

over ten square metres, produce a dimmer illuminance of only 100 lux.

Achieving an illuminance of 500 lux might be possible in a home kitchen with a single

fluorescent light fixture with an output of 12,000 lumens. To light a factory floor with dozens

of times the area of the kitchen would require dozens of such fixtures. Thus, lighting a larger

area to the same level of lux requires a greater number of lumens.

As with other SI units, SI prefixes can be used, for example a kilolux (klx) is 1,000 lux.

Table 2-3 Illuminance for a Few Examples

Example Illuminance, Lux

Total starlight at overcast night 1E-4

Full Moon overhead 0.267

Twilight 10

Overcast day 1000

Full daylight (not direct sun) 10000-25000

Sun overhead 130000

29

CHAPTER 3 METHODOLOGY

3.1 BENCHMARKING

3.1.1 Speed Timing Gate in Market

Nowadays, the global market has 3 main types of sport timing light product. There are:

Single beam gate without Error Correction Processing (ECP). Example: Brower,

Microgate

A single beam with Error Correction Processing (ECP). Example: SMARTSPEED

Dual and triple beam system. For instance, Swift Performance.

Single Beam Gate without Error Correction Processing (Brower, Microgate)

The latest development from Brower Timing System is the Test Center (TC) Timing

System. It is a wireless timing device that enables athletes and coaches to measure time,

speed, count repetitions, input test data and save it all in the TC-Timer memory. It can send

radio transmissions up to one thousand feet and is accurate to thousandth of a second, making

it a highly precise timing tool. The TC-PhotoGate A&B creates an infrared beam that can

start, split or stop the time.

Microgate is another system that develops professional timing with precision, providing

impeccable time measurement for sports. The products mostly has a transmission timing

signals system that is wireless. The system can be connected to any gate, photocell or device

30

with a normally open contact. The speed measurement program via cable and radio allows

the measurement of speed on a base of any length.

Single Beam Gate with Error Correction Processing (Smartspeed)

SMARTSPEED is an innovative product introduced sport timing light gate by a company

known as Fusion Sport who is a wholly owned subsidiary of Grabba International Pty Ltd,

specializing in applying Sports Science to develop education and technology products for a

wide range of sports and activities. It operates with a single beam gates which implement a

technology called Error Correction Processing (ECP) and also known as False Signal

Processing. The best trait of this method is that, there can be any numbers of hand break,

trailing feet breaks and etc – since it only take the largest event of the break and take the start

of the largest event as the starting or ending time.

Figure 3-1 SMARTSPEED by Fusion Sport using single beam with Error Correction Processing (ECP)

31

Figures 3-1 shows how SMARTSPEED does Error Correction Processing (ECP) have

been implementing by Fusion Sport. How these system works will be well elaborated in

Methodology part of this proposal. These systems definitely have significantly improved the

overall result since it can distinguish between valid and invalid signal. Let’s see the

advantages of this systemto make the argument stronger. The advantages of single corrected

beam are numerous based on the research from Fusion Sport:

(1) Real event measurement – timing based on actual event; time is

recorded when the torso crosses the beam.

(2) Flexibility and Configurability – as ECP is innovation software, it

can simply configure (on or off) accordingly depends on the users need.

(3) Ease to use – Single beam corresponds to single photoelectric

sensor, less setup time, less power consume

(4) Cost and power saving – Cut the cost of production, no additional

electronics components and less power demands.

(5) Common sense – Better to use the software to achieve the

requirement rather than spends extra cost on hardware modification.

Dual Beam System (Swift Performance)

Swift Performance Equipment is one of the few timing light manufacturer tried to

improve the reability by introducing extra beams in the existing system (usually two or three

beams per gate). The main idea is two or three beams are placed 30cm apart from each other,

and the gate will be triggered only when both beam were broken concurrently. So, if the

athlete’s hand accidentally breaks one of the beams, the gate will not trigger any signal since

the condition is not met. Besides that, Australia Institute of Sport Network which is one of the

32

world’s leading sport organisation has made two beams system their standard of practice for

the past years.

However, Swift Performance still use two beam system on their latest product named

SpeedLight V2.This product has been critised by its own competitors due to higher cost of

manufacturing, battery requirement as well as maintenance. The two beam system gain

advantage from one point of view which is the complexity of the system software; less time

spend to develop the system software. The theories lie behind these systems is simple. The

two beams just have to be broken concurrently to register as valid signal i.e in the case when

the athlete’s torso passes the gate. But, there is still possibility of the two beams is both

broken concurrently by swinging arms. Therefore, that is the minus side of these systems.

Figure 3-2 SpeedLight by Swift Performance using double beam system

33

So, since error correction processing (ECP) and two beam gate system has been

understood, why not incorporate both of these two things into one system which is called

“Two Beam Gate System with ECP.

Figure 3-3 Typical Error of Measurement (TEM) for the two systems

As indicated by Figure 3-3, typical error increases as distance increases, due to a greater

absolute time and potential for variation between trials. It also indicates that SMARTSPEED

gates typically had a lower typical error at all distances.

34

Figure 3-4 Measure of reliability, Coefficient of Variation (CV%)

The above result demonstrates that single beam gates (with error correction) are

considerably more reliable than traditional dual beam gates, at all distance. This was

particularly evident at the 5m distance, where error measures for SMARTSPEED were

almost half those of the dual beam system, and where timing accuracy is especially important

given the amount of improvement an athlete can expect over such a short distance.

35

3.1.2 Sensor

For building a speed timing gate, we have to use wave emitting sensor. The interrupted

wave will make the sensor to produce a digital signal to the DAQ and the software will run

the program to measure the speed of the athlete.

As discussed in the CHAPTER 2, there are many types of wave emitting sensor

depending of the types of wave, such as ultrasonic sensor and photoelectric sensor. Since

ultrasonic sensor cost higher and more complex to be configured, we will consider the other

alternative, photoelectric sensor as the sensor for the speed timing gate.

There are a few reasons why that particular photoelectric sensor has been chosen to be

used in this project. The reasons can be identified from their advantages as described below :

Long sensing distance – for example the thru-beam type can detect object

more than 10m away.

Can detect almost any object –for example glass, plastic, wood and liquid.

These sensors operate on principle that an object interrupts or reflects light, so they are

not limited like proximity sensor to detecting metal objects.

Fast response time – this feature is very significant since real time

measurement is required. The response time is very fast due to light travels at high speed

and the sensor performs no mechanical operations because all circuits are comprised of

electronic components only.

36

High resolution – these sensors are improved by advanced design technologies

that yielded a very small spot beam and unique optical system for receiving light. This

development enables detection of small objects as well as precise position detection.

Non-contact sensing – little or no damage to the sensor because objects can be

detected without physical contact.

Easy Adjustment – positioning the beam on an object is simple with models

that emit visible light because the beam is visible.

Basically, photoelectric sensors are being classified by 3 basic types. There are being

classified by their sensing method. There are through-beam sensors, diffuse-reflective sensors

and retroreflective sensors.

A through beam photoelectric sensor consists of a receiver located within the line-of-

sight of the transmitter. In this mode, an object is detected when the light beam is blocked

from getting to the receiver from the transmitter.

A diffuse-reflective photoelectric sensor is one in which the transmitted radiation

must reflect off the object in order to reach the receiver. In this mode, an object is detected

when the receiver sees the transmitted source rather than when it fails to see it.

37

A retroreflective photoelectric sensor places the transmitter and receiver at the same

location and uses a reflector to bounce the light beam back from the transmitter to the

receiver. An object is sensed when the beam is interrupted and fails to reach the receiver.

Some photoelectric sensors have two different operational types, light operate (Light-

On) and dark operate (Dark-On). Light-On photoelectric sensors become operational when

the receiver "receives" the transmitter signal. Dark-On photoelectric sensors become

operational when the receiver "does not receive" the transmitter signal.

Figure 3-5 Through Beam Sensor

Figure 3-6 Diffuse-reflective Sensor

Figure 3-7 Retroreflective Sensor

Table 3-1 Comparison among the Through Beam, Diffuse-reflective and Retro reflective Photoelectric

sensors

Through Beam Diffuse-

reflective

Retroreflecti

ve

Sample OMRON E3FZ-T OMRON

E3FZ-D

OMRON

E3FZ-R

Sensing

Distance

15m 1m 0.1 to 4m

Light

Source

(wavelength)

Infrared

(870nm)

Infrared

(870nm)

Visible Red

(660 nm)

Power

supply voltage

10 to 30 VDC, including 10% ripple(p-p)

Current

consumption

45mA max.

(Emitter: 25mA

25 mA max.

38

max.,

Receiver; 20 mA

max. )

Weight approx. 40 g approx. 20 g

For this project, retroreflective sensors has been chosen for several reasons. First of all,

the transmitter and receiver of the sensors is incorporated into a single housing not like the

through beam type. Therefore, it makes the sensor looks compact, ease of setup and highly

mobility. The way these sensors work are the same like the other two types but it requires a

reflector which is mounted opposite to the sensor to return transmitted light back to the

receiver. These sensors have 2 modes of operation; light-on: sensor provide signal when

beam is not interrupted (target not present) or dark-on : sensors provide signal when the beam

is interrupted ( target present).

The condition to be met for the sensor to work effectively is the area of the reflector

must be completely interrupted in order to reliable sense a target and it increases as the

distance between the sensor increases. In that case, it is obvious to say that the sensor will

work at its best since the target is human body (torso) which is far away bigger than the

reflector (max diameter 30mm). More often than not, athlete’s jersey is not highly reflective

that can reflect light back to receiver to make it appear as if the target (athlete) not present

when it passes through the beam. Therefore, retroreflective type is the best method of sensing

compared to the other types.

39

In surveying for market available retroreflective photoelectric sensors, we came into

the two company product. OMRON E3FZ-R series and TELCO SPACEPARK SPPR series.

The table below shows the comparison between these two sensors for different aspects.

Table 3-2 Comparison of OMRON E3FZ-R and TELCO SPACEPARK SPPR

Product: OMRON

E3FZ-R

TELCO

SPACEPAK

SPPR

Sensing Distance: 0- 4m 0-10m

Power Supply

Voltage

10-30V dc +/-

10% ripple

10-30V dc +/-

15% ripple

Current

Consumption

25mA max 65mA max

Response Time 1ms 2ms

Light Source Visible Red

LED (660 nm)

Visible Red

LED (660nm)

Ambient

Illuminance

10000 lux 25000 lux

Ambie

nt

Temperature

Oper

ating:

-25 to +55 ºC -20 to +55 ºC

Stora

ge:

-40 to +70 ºC -40 to +80 ºC

Control Output 100mA / 30V

dc

200mA / 30V

dc

Connection Method Pre-wired cable

or Standard M12

connector

Pre-wired cable

or Standard M12

connector

Housing Shape Cylindrical Cube

Materi

al

Case

Cover

lens

ABS

PMMA

ABS

Polycarbonate

Cost RM240++(excl

uding reflector)

RM445++(excl

uding reflector)

40

In case of sensing distance, TELCO has longer sensing distance compare to OMRON.

However, our requirement for the sensing distance is around 4m so both sensors fulfil our

requirement in term of the sensing distance.

In term of consumption of power supply, OMRON stands better than TELCO as the

percentage of ripple for OMRON is smaller than TELCO. The current consumption for

OMRON is also smaller than TELCO.

Both OMRON and TELCO have short response time. The response time for OMRON

is shorter than response time for TELCO. To make the speed timing gate precise, we will

need a shorter response time sensor. The shorter the response time, the more precise the

speed timing gate.

In term of the ambient to the illuminance (in other word, light intensity), TELCO will

work under better than OMRON sensor as TELCO have greater ambient illuminance. As

stated in CHAPTER 2, the illuminance for a full day light (not direct sunlight) is in the range

of 10000-25000 lux.

In term of the casing, we will need a casing with water proof and well electric

insulating material. Both of the OMRON and TELCO sensors use ABS as the casing material.

So, both OMRON and TELCO sensors meet our requirement.

41

There is a huge gap in term of cost between OMRON sensor and TELCO sensor.

OMRON sensor cost only RM245++ where else TELCO sensor cost RM445++. In term of

cost saving, OMRON will be the choice.

Based on all the considerations above, both OMRON sensor and TELCO sensor meet

our requirements. However, when we consider about the energy consumption, the responding

time, and especially the cost, OMRON will be a better choice. Therefore we choose OMRON

E3FZ-R sensor for this project.

3.2 CONCEPT GENERATION

For system, the six critical sub-problems are faced:

42

The alternative solution concepts for each of the sub-problem above can be obtained

from modifications and improvements of different part of the speed timing gate system

4.3.1 The housing for sensor and bracket

The height of the housing is 350 millimetres which is the average length of the human

body. So the gap between the sensor and reflector are 30 mm away from the edge of the

housing. This is the solution for sub-problem 2. The housing also protects the sensor from

harm in any even that it might fall because of weather condition. The tripod stand has to be

adjusted to a suitable base area to stabilize the equipment.

Sub-problem statement 1:

Storage, Process and Download

Sub-problem statement 2:

Single or Multiple Beam

Sub-problem statement 3:

Ease of Setup

Sub problem statement 4:

Wiring

Sub-problem statement 5:

Realibility

Sub-problem statement 6:

Environmental Condition

The timing gate

system

Figure 3-8 Sub-problems for Speed timing gate

43

4.3.2 Dual beam

For this system, we use the dual beam system with Error Correction Processing (ECP).

With this sub-problem one and two is solved. The sensor used is Omron E3FZ/E3FR which

has a fast storage, process and download feature.

4.3.3 Signal Conditioner

For this is the solution for sub-problem 1 and 5. As we are using NI DAQ 2008 it has a

connection with a PDA in this case we are using a laptop with the software of LABVIEW to

process the signal produce by the Omron E3FZ/E3FR.

4.3.4 Sensor

Since the sensor we are using is Omron E3FZ/E3FR, it is said to be easy-to-setup which

is using the snap and mount installation. This solves the sub-problem 3.

4.3.5 Wiring

Since the sensor being use is Omron E3FZ/E3FR. The installation is not that of a hassle

since we are using a retroreflective type which has a less wiring setup solving sub-problem 4.

4.3.6 Easily Detectable sensor to any material

The sensor can detect any type of body such as plastic, steel and etc proving that it can

be use for the human skin. It also can be used in any weather condition such as sunrays, dust

and etc for solving sub-problem 6.

44

4.3.7 Error Correction Processing

We are solving statement sub-problem 5 when using Error Correction Processing (ECP).

Our target is reducing 5% error or maybe less. The results will be reliable since athletes train

for a year to improve their performance to 5% to 10% every year.

3.3 CONCEPT SELECTION

We apply the concept screening method as an experiment to help me select the best

solution concept for each sub-problem. We have compared the sensor of single beam with

ECP and multi-beam system.

Through the concept screening method, the best solution concepts are selected and

combined to give the final concept for the whole design. We decided that all the selected

concepts are obviously better than the other alternative concepts, thus the second stage of

concept selection methodology, concept scoring method was not carried out. Hence the final

concept for the timing gate system is as follows:

The Speed Timing Gate system will be a dual beam with Error Correction Processing

(ECP). The Sensor used will be Omron E3FZ/E3FR retroreflective since it has a better

feedback in most outdoor condition. The Sensor will be place a proper housing and the gap

between both sensors will be the average length of the human upper body which is 350mm.

The Signal Processer use will be DAQ which will translate the signal directly from the sensor

45

to the laptop and using the software LabVIEW to analyse the results obtain from every test or

real time events.

3.4 MATERIALS

The material selection for mounting of sensor and reflector is significant in the design

process. The main purpose of the housing is to protect the sensor from damages from

environment like sunlight and raining. Hence, the material of housing should have properties

which are water-proof, heat resistant, light-weight and ease to fabricate.

We had compared three different types of materials for the fabrication of the mounting

box of sensor which are ABS (Acrylonitrile Butadiene Styrene), Aluminium Alloy-6061,

Stainless Steel 304.

ABS (Acrylonitrile Butadiene Styrene)

ABS is an amorphous thermoplastic blend. Acrylnitrile contributes with thermal and

chemical resistance, and the rubberlike butadiene gives ductility and impact strength. Styrene

gives the glossy surface and makes the material easily machinable and less expensive.

Generally, ABS has good impact strength also at low temperatures. It has satisfactory

stiffness and dimensional stability, glossy surface and is easy to machine. If UV-stabilizators

are added, ABS is suitable for outdoor applications.

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Table 3-3 Mechanical properties of ABS

Quantity Value Unit

Young’s modulus 2275-2900 MPa

Shear modulus 700-1050 MPa

Tensile strength 41-60 MPa

Elongation 5-25 %

Compressive strength 60-86 MPa

Fatigue 11-22 MPa

Impact strength 0.56-2.2 J/cm

Table 3-4 Physical properties of ABS

Quantity Value Unit

Thermal expansion 50-85 10-6

/K

Thermal conductivity 0.17-0.188 W/m.K

Specific heat 1260-1675 J/kg.K

Density 1060-1080 kg/m3

Resistivity 1e+15

- 2.7e+20

Ohm.mm2/m

Water absorption 0.2-0.45 %

Aluminium Alloy- 6061

Aluminium Alloy- 6061 is a precipitation hardening aluminium alloy, containing

magnesium and silicon as its major alloying elements. It has good mechanical properties and

exhibits good weldability. Aluminium alloy 6061 is one of the most extensively used of the

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6000 series aluminium alloys. It is a versatile heat treatable extruded alloy with medium to

high strength capabilities. Below are the properties of aluminium alloy-6061.

Table 3-5 Physical properties of Aluminium Alloy 6061

Density 2.7g/cm3

Melting point Approx. 580°C

Modulus of Elasticity 70-80GPa

Poissons Ratio 0.33

Table 3-6 Thermal properties of Alumimium Alloy 6061

Co-efficient of Thermal Expansion (20-

100°C)

23.5x106m/m.°C

Thermal Conductivity 173W/m.k

Table 3-7 Electrical Properties of Aluminium Alloy 6061

Electrical Resistivity 3.7-4.0x106Ω.cm

Stainless Steel 304

Stainless steel does not stain, corrode, or rust as easily as ordinary steel, but it is not

stain-proof. Grade 304 is the most versatile and most widely used stainless steel, available in

a wider range of products, forms and finishes than any other. It has excellent forming and

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welding characteristics. It is also excellent in a wide range of atmospheric environments and

many corrosive media.

Table 3-8 Mechanical properties of 304 grade stainless steel

Tensile Strength (MPa) min 515

Elongation (% in 50mm) min 40

Hardness Rockwell (HR B) max 92

Table 3-9 Physical properties of 304 grade stainless steel

Density (kg/m3) 8000

Elastic Modulus (GPa) 193

Thermal Conductivity (W/m.K) at

100°C

16.2

Specific Heat (J/kg.K) 500

Electrical Resistivity (nW.m) 720

After comparing all the three types of material above, the best material for fabricate the

mounting box of sensor is ABS. This is because it is water-proof (lowest water absorption

which is 0.2-0.45%), lightweight (1060-1080 kg/m3) and high heat resistivity (lowest heat

conductivity value of 0.17-0.188W/m.K) compare to aluminium alloy-6061 and stainless

steel 304.

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3.5 FABRICATING

A proper housing or mounting is needed to hold the sensors and reflector available in

place. The idea of the system is so that the sensor and reflector is parallel to each other so that

the projected beam from the sensor to the reflector will be reflected to desired orientation.

Thus an exact dimension housing or mounting is crucial for the sensor have to be fabricated.

We fabricated housing for the sensor and also the bracket for the reflector. We use the

metal cutting band saw and drilling machine to cut and drill the aluminium tube. The material

used for the housing is aluminium which is low in cost and durable. The use of the housing is

to hold the sensor in place and the plate that is fabricated for the reflector is also the same

size and the gap between the sensor and reflector is the same so it is parallel. So the sensor

reflects with the proper angle. The tripod stand is adjustable to calibrate the sensor to produce

the proper signal.

3.5.1 Fabrication of the sensor housing.

The material use for the housing of the sensor is aluminium alloy. It is light weight and

durable. The material can with stand harsh weather condition comparing to normal steel

which would corrode easily when in contact with moisture. We have the ready hollow

aluminium alloy in the lab and began to cut the long alloy into specified measurement.

350mmx75mmx45mm. After the cutting the long alloy to a desire dimension we proceed

with drilling using the drilling machine. Drilling to 20millimetres in diameter as coherently

the same as the snap mount of the sensor. The edges of the housing is smoothen using

sandpaper to shapen the edges.

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3.5.2 Fabrication of L-plate for reflector

The reflector plate is design to be an L shape plate to hold the reflector in place. Two

small diameter of 6.5mm was drill to the reflector plate to fit the snap mount reflector. The

same procedure was use to fabricate the plate for the reflector was use as for the sensor.

3.5.3 Equipment Used

Figure 3-9Milling machine

Figure 3-10Metal Cutting Band Saw Machine

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3.5.4 Photo of Fabricating Process

Figure 3-11 Cutting the aluminium tube using metal cutting band saw machine

Figure 3-12 Drilling the tube using turret milling machine

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Figure 3-13 Mounting box for the sensor

Figure 3-14 Drilling process for mounting box of sensor

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Figure 3-15 Drilling process for mounting box of sensor with the aid from lab assistant

Figure 3-16 Surface finishing for mounting box of sensor

Figure 3-17 Sawing process for bracket of mounting box of sensor

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3.6 COST

The cost to produce the whole speed timing gate system was estimated. The cost for

some raw material is taken from the market price from the manufacturer. The manufacturing

cost will not be included we only fabricate one unit of the system to run the experiment.

Table 3-10 Cost Estimation for the Speed Timing Gate System

Part Material Unit Cost per unit

(RM/unit)

Total Cost (RM)

Mounting for sensor ABS 3 60 180

Mounting for

reflector

3 10 30

Photoelectric sensor

(OMRON E3FZ)

6 275 1650

NI-USB 6008 1 576 576

Tripod stand 6 110 660

Total cost : RM3096

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CHAPTER 4 RESULT AND DISCUSSION

4.1 SYSTEM LAYOUT

In our speed timing gate system, there will be three gates. One is at the starting point,

one is at the finishing point and another one is at the middle of that two gates. We will place

the gates like Figure 4-1. The distance between two gates will be 10m. For each pair of gate,

two photoelectric sensors will be used since our system is using the concept of dual-beam

with error correction processing. The distance between the sensor and the reflector will be up

to 4m (maximum sensing distance for the sensor) so that we can ensure the space is big

enough for an athlete to run through.

Figure 4-1 System Layout

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Figure 4-2 Schematic diagram for the system layout

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4.2 PRODUCT SPECIFICATION

Basically, our speed timing gate system consists of two sections: Data Collecting section

and Data Processing section. (Figure 4-3) components in the data collecting section include

the sensors, reflectors and the mounting racks for the sensors and reflectors. (Figure 4-4For

data processing section, the hardware components will be the DAQ hardware and the

computer.

Figure 4-3 Sections in the system layout

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Figure 4-4 Schematic diagram for the system layout

4.2.1 Data Collecting Section

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The function for this section is to collect data from the athlete. The sensor will generate

signal when the athlete pass through the gates and the signal will transfer through cables to

the Data Processing section.

Components:

Sensor: OMRON E3FZ-R

Reflector: OMRON E38-R49

Figure 4-8 Dimension of the reflector

Figure 4-5 Dimension of sensorFigure4-6 Hardware

Figure 4-7 Components of the system

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Mounting for Sensors and Reflector

Figure 4-11 Mounting for sensor

Figure 4-9 Mounting for sensors

Figure 4-10 Mounting for Reflector

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Mounting rack for Reflector

Figure 4-13 Mounting Rack for Reflector

Hole to snap

the reflector Refl

ector

To join

with the tripod

Figure 4-12 Trajectory View of the mounting rack for the

sensor

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Stand for the mounting rack

We will use common camera tripod as the stand for the mounting rack.

Figure 4-15 Camera Tripod Stand

Figure 4-16 Sample CAD model of a Tripod Stand

Figure 4-14 Trajectory view of the mounting rack for the reflector

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4.2.2 Data Processing Section.

In data processing section, the main hardware component is the DAQ hardware and the

computer.

DAQ hardware:

NI USB-6008 will be used as our data acquisition instrument. The function of this

instrument is to convert the data or signal from the sensors to digital signal so that the data

will be processed in the software in computer

Computer:

A computer installed with LabVIEW software will be connected to the DAQ hardware.

The software LabVIEW will run the program to calculate and record the speed of the athlete.

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User Interface

The user interface from the software will look like Figure 4-16.

Figure 4-17 Sample Front Panel for the User Interface

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4.3 DISCUSSIONS

The sensor has to be positioned in an appropriate housing for it to be aligned straight

perpendicular to the track. Then, the beam projection can be horizontal at 90 degrees. Some

researches on the type of mounting available for a Dual beam installation in the market was

done but we were unable to find on a proper one in the case of the sensor we are using for the

test. Therefore, we have to design and fabricated our own mounting bracket which we feel

that is appropriate to be used.

Since the sensor we pick, Omron E3FZ-R does not have a wireless setup configuration.

We have to come out with a proper and neat type of system so that the set up will be tidier

and will not obstruct trails when athletes are running. The mounting bracket has to be able to

be calibrated easily or in other word, less calibration is need for setting up. We require he

material for the product to be water-proof and light-weight for sustainability and the ease of

setup of the system.

After looking at the consideration made above, we decide to fabricate a mounting for the

sensor shown in Figure 4-10. The dimension is shown in Figure 4-11. The modification is

based on the consideration that we feel is best to produce the best results for the speed timing

gate in which case we are using retro reflective photoelectric sensor (Omron E3FZ- R).

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4.3.1 Material for the Mounting Bracket

The body of the housing is made out of acrylonitrile butadiene styrene (ABS). The

example of finish product made with ABS are helmets, bathroom handles and etc. The

advantage of ABS is that this material combines the strength and rigidity of the acrylonitrile

and styrene polymers with the toughness of the polybutadiene rubber. The most significant

mechanical properties of ABS are impact resistance and toughness. Although the cost of

producing ABS is higher, it is considered superior for its hardness, gloss, toughness and

electrical insulation properties. Since the design of the body is like a hollow tube, it will be

lightweight and the production cost is also reduced. The hollow tube also helps in wiring

when setting up. The sensor is attached to the small opening of the front face of the mounting

bracket. A snap and mount installation (come with OMRON E3FZ-R) is used for the sensor

making it less time consuming when setting up.

4.3.2 The Dimension

The mounting bracket is 350mm in height, 45mm in length and 75mm in breath. The

average human height is 170cm-176cm. So we can assume that the height of the trailing hand

to the shoulders is approximately 350mm. The distance of the opening for the placement of

the sensor is 50mm apart from the edge of the fabricated mounting bracket. The distance

between the sensors in the dual beam system is 250mm apart making it readily contactable

when the beam sensing is mainly targeting the torso area of the body.

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Figure 4-18 Poorly designed multiple beam gate system

The light beams must be broken at the same time to obtain a proper reading. If the

problem such as Figure 4-18 above happens, we can adjust the height of the tripod stand to a

desirable height.

4.3.3 The Sensor and Mounting Bracket Set Up

As stated in 4.3.2 the opening of the mounting bracket for the installation of the sensor is

20mm in diameter. The sensor is 15mm in diameter. Thus making the placement to be a snap

and mount is suitable. A snap mount holder is place at the opening of the mounting bracket

making the sensor sliding through the opening with ease and secure.

4.3.4 Wiring Set Up

After installing the sensor to the mounting bracket, a connector is connected with the

sensor located at the back of the mounting bracket. Two more holes are drilled at 12mm

diameter to allow for this wiring installation. The connectors used for this installation is using

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I/O sensor connector. Either a straight or L-shape connector can be used. The wires are coiled

up around the tripod stand and finally connected to the Data Acquisition Instrument (DAQ)

where it is placed in the large circuit board box. These wires are connected to a multi

connection then to USB and the signal is transmitted to a Personal Computer (PC) for the

signal to be further processing.

4.3.5 The Tripod Stand

The tripod stand used for the mounting bracket has to be able to lock the base by thread

like a nut and screw application. It consumes less work to install the system. Using a tripod is

also saving space for keeping. The base of the tripod stand should be positioned with a

sufficient base area to keep the timing gate from falling down where it can damage the sensor

inside.

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CHAPTER 5 CONCLUSION AND

RECOMMENDATION

5.1 CONCLUSION

A speed timing gate system is designed to measure the speed of athlete instrumentally

using DAQ. The timing gate systems designed is dual beam with error correction processing

so the result obtained much more accurate. We have chosen photoelectric sensor (OMRON

E3FZ) as light beam for this system and NI-USB 6008 as data acquisition hardware in this

project. The system designed is also lightweight, adjustable and portable for the convenient

of the user. However, there is some problems raised and improvements can be done for speed

timing gate systems as further research in future.

5.2 RECOMMENDATION

There are rooms for improvement in our design. We will discuss them part by part of

our design

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5.2.1 Mounting for sensor

In our product, the positions of the mounting for sensors are fixed. If problem like

Figure 4-17 occurs, we will have to fabricate a whole new mounting bracket for different

position of sensors. This definitely will be a waste of cost and time. This problem can be

avoided by fabricating the mounting bracket to be having more option or more hole for

mounting for sensors. In this case, the position of the sensors will be adjustable. Number of

beam can also be changed for better testing result.

5.2.2 Mounting for the reflectors

Same with the mounting for sensors, our product’s mounting for reflectors are also

having fixed position for mounting. To solve the problem, we can make the mounting bracket

for the reflector to have more mounting position option like what suggested in 5.2.1. Or else,

we can also solve this problem by replacing the reflectors to bigger reflector so that all beams

emitted by the sensors can be reflected by a single reflector.

5.2.3 Sensors and Connectors

We have many sensors in the system and the wiring connection are very long. Wiring

for those sensors may be messed up with each other. Therefore, to prevent this kind of

problem, we may consider using sensors with wireless connection. By this way, the cost for

wires and connectors can be saved.

5.2.4 Appearance

We can improve the outlook and appearance of the mounting bracket to be more. May

be we can have a better shape and have some color for the mounting bracket. Having a nice

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and attractive appearance can attract more customers to buy our product if we commercialize

the product.

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CHAPTER 6 REFERENCES

1. (URL-http://en.wikipedia.org/wiki/Sprint_%28running%29), 9/10/2011

2. (URL-http://www.topendsports.com/testing/timing-gates.htm), 9/10/2011

3. (URL-http://www.fusionsport.com), 11/10/2011

4. D'Auria,S.,Tanner,R.,Sheppard,J. and Manning, J. (2006) Evaluation of Various

Methodlogies used to Asess Sprint Performance. Paper presented at the Australian Institute of

Sport Applied Physiology Conference, 2006

5. Earp & Newton (2010) Analysis of false signals in electronic timing systems: single

and double beam gates. Paper presented at the 2010 Australian Strength & Conditioning

Association Conference, Gold Coast, Australia.

6. (URL-http://www.clickautomation.com/o/photoelectric-sensor.php), 16/10/2011

7. (URL-http://www.ifm.com/ifmus/web/pinfo1_40_10_40_30.htm), 16/10/2011

8. (URL-http://www.tektron.ie/retroreflective.htm), 19/10/2011

9. (URL-http://en.wikipedia.org/wiki/Proximity_sensor), 19/10/2011

10. (URL-http://en.wikipedia.org/wiki/6061_aluminium_alloy), 26/10/2011

11. (URL-http://designinsite.dk/htmsider/m0007.htm), 26/10/2011

12. (URL-http://www.matbase.com/material/polymers), 26/10/2011

13. (URL-http://en.wikipedia.org/wiki/Stainless_steel), 26/10/2011

14. (URL-http://www.azom.com/article.aspx?ArticleID=3328), 30/10/2011

15. (URL-http://www.what-is-net.info/what-are-proximity-sensors.html), 10/11/2011

16. (URL-http://www.ifm.com/ifmus/web/pinfo1_40_10_40_40.htm), 15/11/2011

17. (URL-http://www.ni.com/labview), 20/11/2011

18. (URL-http://www.saf.com), 24/11/2011

19. (URL-http://www.google.com/products/catalog), 27/11/2011