Engineering a Device to Locate Golf Balls
Ryan Smolenski
Stem Research Project
Massachusetts Academy of Math and Science
February 14, 2013
Golf Ball Location 1
Table of Contents
Abstract
2
Introduction
3
Literature Review
4
Methodology
14
Results
18
Data Analysis and Discussion
25
Conclusions
27
Limitations and Assumptions
28
Applications and Future Experiments
30
Literature Cited
34
Acknowledgements
36
Golf Ball Location 2
Abstract
Golf balls can be difficult to locate after they are driven by golfers, especially when they
land at a far distance. A location device was built to detect a golf ball, so that searching for it
would be less time-consuming. A standard golf ball was cut in half, and the inner material was
removed. A circuit board comprising a button cell battery, a power switch, a transmitter, an LED,
a resistor, and two capacitors was placed in the ball. An antenna was built with a wooden rod, a
coaxial cable, six cable raps, a reflector, a vibrator, and two directors. Another circuit board,
which contained a 9-volt battery, four resistors, three capacitors, a power switch, a receiver, a
cell, an oscillator, and a headphone jack, was soldered to the coaxial cable. A pair of headphones
was connected to the headphone jack, and the apparatus was tested. The antenna received the
signals sent by the circuit board in the golf ball, and the pitch emitted by the headphones
determined the distance between the ball and the antenna, 109m max. The volume indicated both
distance and direction. Large objects interfered with the accuracy. In the future, the apparatus
could be used by people with vision problems.
Golf Ball Location 3
Introduction
The Game of Golf
Golf is a casual sport; it does not involve any running, and golfers can move at their own
paces. Players start out in an area called the teeing ground and hit the ball with a club. The
golfers then proceed to where they hit the ball by walking on foot or by riding in a golf cart.
Once the ball is hit into the hole, in an area called the green, the same process is repeated
eighteen times. The goal of golf is to complete the game with as few strokes as possible.
In order to make the game more interesting, obstacles and hazards are placed in various
locations. The Official Rules of Golf state that a hazard is water, a bunker, or a sand trap in the
ground. Trees and thick grass called rough are considered hazards by some people as well. The
ball does not need to be directly on an obstacle to be considered in it. For example, the area
around water is marked with flags, which indicate the land surrounding it within is a threat
(Kelley, 2012). Figure 1 shows a typical golf course, with hazards surrounding it.
Water
Out of bounds
(brown)
Long grass
called rough
(dark green)
Trees
Short grass called
the fairway (light
green)
Sand traps called
bunkers (white)
Figure 1.Golf course layout. Most golf courses comprise a landscape with trees, bunkers, and
water (“TCU golf clubs”, n.d.).
Golf Ball Location 4
Literature Review
Golf Ball Retrieval
Hence a need has become obvious for retrieving golf balls. Some people walk to them,
while others with special licenses can pay to ride in a golf cart (“New rules for golf carts”, 2012).
Locating the golf ball is not always straightforward. If the ball was hit into a patch of long grass,
especially at a far distance, then it would be challenging to locate. In any case where the ball
cannot be retrieved, substitute golf balls with identification markers may be used. Even though
golf balls may come in different colors, they all share the same basic design, as shown in Figure
2.
Figure 2. Golf ball design. All golf balls contain
composite material that is surrounded by a shell.
Past Golf Ball Detectors
Recently, golfers have expressed an interest in locating golf balls by using detectors. The
cost per detector varies on how advanced it is. There are several different kinds of golf ball
detectors, and each uses a unique way to find the ball. One method involves photo imaging,
Golf Ball Location 5
which can only detect white balls. The ball needs to be at least 1% visible and within 10.7 meters
of the device (Bodamer, n.d.).
The handheld device called the Ballfinder Scout scans the surrounding area using a
digital imaging system. When the ball is found, the Ballfinder Scout buzzes and an LED light is
targeted towards the ball (Bodamer, n.d.).
A third example is the Visiball ball finder, which is in the form of eye spectacles. It
absorbs as much light as it can, but allows light to reflect off the ball. As a result, the ball will
appear to be much brighter than its surroundings. Adaptions have been made for people that
actually wear prescription glasses. The Visiball ball finder is less expensive to manufacture than
the Ballfinder Scout (Bodamer, n.d.).
The Prazza Golf Ball Finder (Figure 3) uses radio transmission. Only a handset and a
proprietary golf ball are needed, which connect within a range of 100 meters. Retailers demand
high prices for this apparatus, such as a discount price of $299.95. The golf balls emit a radio
signal and the handset will receive it. The handset will then give the location of the ball, showing
where it is on a screen and emitting sounds. The device will last up to eight hours with batteries.
Figure 3 shows the Prazza Golf Ball Finder (“Prazza golf ball finder”, n.d.).
Figure 3. Prazza ball finder. One example of a device
that locates a golf ball using radio waves is the Prazza
ball finder. (“Prazza golf ball finder”, n.d.).
Golf Ball Location 6
The idea of light detecting and ranging was considered on a few occasions. LIDAR
detectors search for infrared laser pulses. Because of the thinness in the laser, LIDAR detectors
are less accurate than other golf ball location devices (“How do laser detectors work?”, 2004).
Various apps that use GPS technology are increasing. There exist golf balls that have a
GPS system already built into them, which lets the app user know the exact location of the ball.
At least one golf-related project has been completed using GPS; Chris Savarese devised
RadarGolf, a locating system for golf balls. Proprietary balls are installed with a microchip, and a
locating handheld uses GPS technology and will sync to the chip. Within a range of 9.14 to 30.5
meters, the handheld will emit sounds as it navigates closer to the golf ball (Grass, 2011).
Circuitry
Knowledge of how circuit boards work has become essential in engineering a device that
can locate golf balls. Circuit boards contain chips that have metal prongs at the ends of them, as
shown in Figure 4. The prongs send electrical discharges and travel through wires in the circuit
board to other chips. The discharges do not occur all the time; at specific times a certain amount
of electricity is passed (Andrews, 2009).
Prongs (gold)
Figure 4. Parts of a circuit board. A circuit board
comprises electronic components, including prongs,
buzzers, and oscillators (“Circuit boards / PCB”, n.d.).
Golf Ball Location 7
There are many different types of components in circuit boards, and each result in
mathematical computations that the majority of electronics use to carry out functions (Andrews,
2009). Figure 5 shows a list of circuit board components, along with a description of their
function.
Component
Wire
Wires joined
Circuit Symbol
Picture
Function of Component
Used to pass current between components.
Current passes between them.
Wires not
joined
Current does not pass between them.
Op-Amp /
Timer
It takes in voltage and multiplies its value.
Battery
It supplies energy, which is transferred by the
wires. The larger terminal is positive (+).
Earth
(Ground)
It contains 0 v of electricity, so it is not used
often.
On-Off
Switch
2-Way Switch
Resistor
It controls the flow of current.
It controls the flow of current, in two directions.
It resists some of the passing current, conserving
energy. This image shows one of several varieties
(“Industrial and scientific,” n.d.).
Golf Ball Location 8
Capacitors
It stores energy, coming in many different
models. This image shows one of several
varieties (“Industrial and scientific,” n.d.).
Potentiometer
It has an adjustable knob to control voltage and
volume
Transmitter
N/A
It takes a signal, modulates it, and sends it to the
antenna.
Receiver
N/A
It receives the modulated signal sent by the
antenna, and demodulates it to an electrical signal
that is then carried by the wire.
Speaker
A speaker emits sound.
Headphone
Jack
It provides a place for a headphone and sound
signals to meet.
LED Light
Light-emitting diodes emit light with minimal
energy.
Figure 5. Circuitry symbols, pictures, and descriptions. This is a list of components that can be found in
circuitry, as well as their description (Hewes, n.d.).
Radio Transmission
Progress in the area of radio transmission has created a surge in locating lost apparatus.
Wireless instrument networks have been used for several years, being used only by the military
when they were first released.
Golf Ball Location 9
When wireless networks are set up, the type of transmission frequency needs to be
decided, either licensed or unlicensed, From the U.S. Federal Communications Commissions, the
licensed require an application procedure. The unlicensed have limits on the transmission of the
highest power (Eren, 2006).
There are two components in radio transmission – a transmitter and a receiver (see
previous table). A transmitter takes an electrical signal and modulates it. Then, the signal is sent
through the air until it finds the nearest receiver. The receiver then takes it and converts it to a
usable electric signal.
Radio transmitters are reliable and cost friendly, opening up even more possibilities.
Several devices use them, ranging from microwaves to clocks. Even GPS technology uses radio
waves to a certain extent; they transmit data to the satellites and the satellites return it. The
technology is simple to construct (Brain, n.d.).
Antennas
When radio transmission occurs, an antenna (Figure 5) is needed to continuously radiate
the signals modulated by the transmitter. The receiver takes that signal and uses it to perform
other functions. Antennas need to be a certain size, however, for this to work properly. The
formula to find the size is to multiply the wavelength by 11.99 meters; the wavelength is equal to
984 divided by the frequency. The closer the proper length is, the better it works (“How does a
CB radio antenna work?”, n.d.).
Golf Ball Location 10
Figure 6. Parts of an antenna. An antenna
comprises two directors, a vibrator, and a
reflector. Those take a modulated signal made by
a transmitter and give it to a receiver.
Basic antennas are easy to construct. They require a wooden or plastic base, a cable, a
transmitter, and at least four pieces of copper wire. The wire is used to make a reflector, a
vibrator, and at least two directors. While the vibrator and the reflector control the signal
exchanges, the directors allow the device to be more accurate. Dr. Fred J. Looft at Worcester
Polytechnic Institute in Massachusetts claimed that if the amount of directors were to increase on
an antenna, the size and spacing of each copper wire would decrease to account for the change in
frequency (personal communications).
Antennas are also sensitive; the slightest changes to the apparatus could change the way it
behaves. The antennas need to be as straight as possible, and the wire size needs to be indirectly
proportional to the frequency.
Golf Ball Location 11
Engineering Plan
Engineering problem being addressed:
Golf balls can be difficult to locate after they are driven by golfers, especially when they land at
a far distance.
Engineering goal:
The goal of this project was to engineer an accurate and inexpensive device to locate a golf ball.
Description in detail of methods or procedures:
The first thing to do was to research the different methods of locating matter. People can
locate roughly anything by using sonar, radar, tagging, quantum dots, GPS, and radio
transmission. Sonar is when objects emit a sound wave and the wave is reflected back at them,
producing an echo. Sonar can travel for thousands of miles. Depending on the frequency of the
echo, that is how animals know how big an organism or area is. Several animals with poor
eyesight use it, especially underwater. Bats, dolphins, and whales are among them.
In radar, signals are sent between three radar installations, where they will ping in a
triangular method. For example, in the golf project, the locations could be a tower, the ball, and
the location handheld.
When animals are tagged, scientists can locate them at any given moment. Satellite
tagging is done so that scientists can research animals’ migration patterns and movements. The
process occurs between a satellite and a receiver. Data transmitted includes latitude, longitude,
date, and time. Two types of satellite tagging exist for marine organisms. One is instantaneous
Golf Ball Location 12
and the other is when the organism surfaces. Archival tags are used to find out the living
conditions of an animal, so that scientists can learn how the animal reacts to changes in its
environment. There is no way to transmit the data, so scientists must manually retrieve the tags
(Goetz, 2012).
Quantum dots, or semiconductor nanocrystals, are micro-sized molecules that contain
electrons. The amount of electrons changes the energy levels of the dots. Quantum dots are the
result of when thin semiconductor films bend due to the difference in lattice structures that the
films were originally formed. They are used in abundant electrical devices, including
semiconductors for cascade lasers, injection lasers, quantum computers, semiconductors for
photo detectors, and places for storing information (Mishra, n.d.). When the semiconductors
change, they emit unique colors. The colors can be injected into components of the human
bodyto locate biomolecules (“Quantum dots - what are quantum dots, why are they important
and what applications are they used in?”, 2005). Quantum dots are not widely used because they
are relatively new and expensive. In the future, however, they may be used on currency so that
counterfeit money will become obsolete.
When a golf ball is hit, acceleration occurs for a brief time. As shown in Table 1, the gforce was calculated. Its purpose is to find an appropriate force to test the durability of the ball.
Table 1. The work shown to calculate the g-force exerted on a golf ball when it is hit (Elert, 2001).
Realistic values for the situation




Initial Velocity = 0 m/s
Final Velocity = 41 m/s
Mass of ball = 0.046 kg
How far the force was applied for
(change in distance) = 0.010 m
Obtaining acceleration




VF2 = VI2 + 2aΔx
(41 m/s)2 = (0 m/s)2 + 2a (0.010 m)
1681 m2/s2 = (0.02 m) a
a = 84050 m/s2
 G=a/g
 G = (84050 m/s2) / (9.8 m/s2)
 G = 8576.53
Obtaining applied force
 F = ma
 F = (0.046 kg) (84050 m/s2)
 F = 3866.3 N
 G=F/g
 G = (3866.3 N) / (9.8 m/s2)
 G = 394.52
Golf Ball Location 13
The location device would need an antenna, a transmitter, and a receiver. An antenna was
constructed with a wooden rod, a coaxial cable, six cable raps, a reflector, a vibrator, and two
directors. A circuit board that contained the receiver, a speaker, and two AAA batteries was
made and attached to the coaxial cable of the antenna. Then a circuit board that contained the
transmitter was built. Eventually, the two devices were tested in the woods (where there are a lot
of trees) and on a football field (where the distances are marked), and the results were recorded.
Many golf balls were cut apart to find out which method would be the best for putting in
the transmitter. After sawing some in half and drilling holes in others, it was decided that it
would be best to use a milling machine that would both saw the ball in half and dig out some of
the composite material.
The location apparatus went through a few modifications. The speaker was replaced by a
headphone jack, and the two AAA batteries were replaced by one button cell. Smaller cable raps
were fastened on, the coaxial was coiled up, and a transparent box containing the transmitter was
put under the antenna. An LED light and nail polish was put on the switches to indicate that the
power was on. Eventually, the apparatus was tested on a football field (where the distances are
marked) and in the author’s backyard (for convenience), and the results were recorded.
Golf Ball Location 14
Methodology
An antenna (mass of 290 g, 80 cm x 34.5 cm x 14 cm) was constructed with a wooden
rod (beige, 70.5 cm x 3 cm x 2 cm), a wooden handle (dull green, 9.5 x 3.5 cm x 12 cm), a
coaxial cable (black, 1.52 m long,), six cable raps (black, mass of 1 g, 19.5 cm x 0.5 cm) and
four pieces of wire (copper, 2 mm diameter). The space between the reflector (34.5 cm) and the
vibrator (28.5 cm) was 13.1 cm. The space between the vibrator and the first director (31.2 cm)
was 18.6 cm. The space between the first and second directors (30.6 cm) was 29.5 cm.
Figure 7. The first prototype. The
first model of the location device.
The holes were drilled in the direct middle of the wooden frame (1cm). The handle was
screwed (1cm diameter) to the end of the rod, after the reflector. The coaxial was soldered
(Oatey Brand, contains bismuth, copper, silver, and tin) to the vibrator. A hole (5mm) was drilled
6cm away from the end of the rod, and the other end of the coaxial went through.
A receiver (model RWS-371, frequency of 433.92MHz, 5-volt) was soldered onto a circuit board
(3cm x 2cm) (“RWS-371 RF module series,” n.d.). Pin one was connected to the ground, pin two
to the transmitter, pins 4 and five are the receiver voltage, pins six and seven are to the ground,
and pin eight is to the antenna. Four resisters were pinned to the front, and one capacitor was on
Golf Ball Location 15
each side. A diode was placed in there for volume control. The coaxial from before was soldered
onto pin four. The battery was soldered the op-amp (-) and the on-off switch (+). A speaker
(yellow, radius of 3cm), was attached to the negative terminal.
Figure 8. Receiver. The receiver of the location device.
An on-off switch of the same of the same kind was soldered to a new circuit board (3 x
2.5). An op-amp was placed on the far side of the circuit board, and the transmitter (model TWSBS, frequency of 433.92MHz) was placed in between them (“TWS-BS RF module series,” n.d.).
The ground was connected to pin one, an operational amplifier to pin two, a battery to pin three,
and the antenna to pin 4 (Gray, n,d,). Two capacitors (yellow and brown) and a resistor were
soldered to the op-amp. Two AAA batteries (Rayovac, 11g each) were set up.
Figure 9. Transmitter. The transmitter of the location device.
Golf Ball Location 16
The two devices were tested in the woods (Oxford, MA, -3.89°C) to test how directional
the device is. Then they were tested at a football field (Oxford High School, Oxford, MA 6.67°C) for distance, and the results were recorded.
Figure 10. Forest of illusion. The trees were a source of
reflection.
At WPI, a golf ball (Wilson brand, mass of 46 g, diameter of 42.7 mm, inner core made
out of black proprietary material, diameter of 3.81 cm, volume of 28.94 cubic cm, outer shell
made out of white thermoplastic) was sliced in half. A milling machine was used to remove parts
of the insides of the halves.
The location apparatus went through a few modifications. The speaker was replaced by a
headphone jack, and the two AAA batteries were replaced by one button cell. Smaller cable raps
were fastened on, the coaxial was coiled up (radius of 6cm), and a transparent box containing the
transmitter circuitry was super glued under the antenna.
Figure 11. Final location device. The changes
made include adding a headphone jack and a
protective box.
Golf Ball Location 17
An LED light and nail polish was put on the switches to indicate that the power was on.
Figure 12. Button cell battery. Instead of AAA batteries, a
button cell battery was used.
Eventually, the apparatus was tested on a football field (Oxford High School, Oxford,
MA -5.55°C and in the author’s backyard (6 Heritage Drive, Oxford, MA, 0°C), and the results
were recorded.
Figure 13. Testing at home. From a distance of 30m, tilting
the location device altered the results.
Golf Ball Location 18
Results
The golf balls needed to be as close to their original shape and weight as possible. The
amount of displaced material, including the black composite material, needed to be minimal. The
overall appearance of the golf ball should not look any different than before. Several different
methods of opening the ball and placing the chip inside were tested for durability, which include
cutting it in half and sealing it with weld, drilling a hole to the middle, and milling the inside of
it. The latter of these designs was the only one to fit the transmitter, but drilling a hole to the
middle kept it close to the original mass of the ball.
If the project were to be continued, the circuit board inside the chip will need to be tightly
compacted so that it will not break. It will need to withstand at least 3866.3 N of force. The
inside of the golf ball will need to use a sealant that will completely surround the chip, absorbing
shock at the same time. If part of the shell of the golf ball was displaced, it will need to be
replicated.
The prototype had its own set of criteria. If the antenna pointed in the direction of the
ball, it would get louder; if it moved away, the volume would decrease. As the distance between
the antenna and the transmitter decreased, the pitch would need to lower and the volume would
need to increase. The device should have a high resistance to any reflection from obstacles on the
field, and no interference of any kind should occur. The volume should be loud enough to hear,
even if there is a lot of wind blowing around. The apparatus would need to be safe enough for a
child to handle, and it should not break easily. It should be light and comfortable to handle, like
any other location device. The materials it contains should be inexpensive and the unit should be
professional design. Table 1 summarizes the criteria for each version of the apparatus.
Golf Ball Location 19
Table 1. The matrices of each version of the location device.
Location Device Matrices
1. When pointed towards the transmitter, the volume
increases
2. The further away the transmitter and receiver are, the
lower the volume goes
3. Resistance to reflection
4. Loud enough to hear
5. Safe and resists to breaking
6. Portability (weight and size)
7. Low cost and effort to manufacture
8. Aesthetically pleasing
Total
Percent
Max Points
10
Design 1
8
Design 2
7
9
8
9
8
7
6
5
4
3
52
100%
4
3
2
3
3
2
33
63.5
4
7
4
2
2
2
37
71.2
Both of the volumes of the devices increased as they pointed towards the transmitter, but
Design 1 worked the best. Both designs worked far better than predicted, and Design 2 had a
maximum distance of 109.35 m. Both models did not work well inside houses; the walls
reflected some of the electromagnetic waves, altering the results. Design 1 used a quiet speaker
that could barely be heard. Design 2 omitted the speaker and replaced it with a headphone jack,
so the sounds could be heard much clearer. Both devices are sensitive because there are many
things that could happen to them, like the antennas being bent and the circuitry breaking. Design
2 included a box that cradled the receiver so it would not break. The antennas were heavy, which
decreased the user’s comfort. The box in Design 2 added to the weight. Both devices were cheap
compared to other golf ball finders, like the Prazza Golf Ball Finder, which is priced at three
hundred dollars (“Prazza golf ball finder”, n.d.). Overall, the antennas were different looking
from other antennas, such as the one in Figure , but they were appealing to the eye.
Golf Ball Location 20
Figure 14. Professional antenna. This is an antenna
that is more aesthetically pleasing to the eye than the
constructed ones (“DIY yagi antenna for 1200MHz
(2400MHz)”, 2010).
The location devices were tested to see if they could locate the ball or not, from various
distances and angles. Figures 15 through 17 show the results for both versions of the device
when it was tested for its maximum distance.
Maximum Distance (Meters)
140
120
100
80
60
40
20
0
1
2
3
4
5
6
Version 1
7
8
9
10
11
12
Version 2
Figure 15. Trials done for distance. The various distances recorded as maximums for each
design.
Golf Ball Location 21
Average Max Distance (Meters)
140
120
100
80
60
40
20
0
1
2
Figure 16. Averages for distance. The averages for the maximum distances for both versions.
Version 1
Version 2
AVG
97.97
109.35
STDEV
11.15
7.41
%RSD
11.39
6.78
Figure 17. Maximum distance technical results. The average, the standard deviation, and the
robust standard deviation.
The rotation angles from a 30 m distance were tested. The device was held parallel to the
ground, and the copper wires were horizontal. The device stayed stationary, but it was rotated so
that the copper wires were no longer parallel, as shown in Figures 18 through 20.
Golf Ball Location 22
Maximum Angle of a 90° Rotated Antenna
40
35
30
25
20
15
10
5
0
1
2
3
4
5
6
Counterclockwise
7
8
9
10
Clockwise
Figure 18. Trials done for angles. The various changes in angle degrees recorded as maximums for
counterclockwise and clockwise motions.
Average Max Angle of a 90° Rotated Antenna
40
35
30
25
20
15
10
5
0
1
2
Figure 19. Averages for angles. The averages for the maximum angles for both directions. 1 means
counterclockwise and 2 means clockwise.
CCW
CW
AVG
20.15
29.06
STDEV
5.98
4.41
%RSD
29.70
15.18
Figure 20. Maximum angle technical results. The average, the standard deviation, and the robust standard deviation
for counterclockwise (CCW) and clockwise (CW) motions.
Golf Ball Location 23
The rotation angles from a 30 m distance were tested. The device was held parallel to the
ground, and the copper wires were horizontal. The device stayed stationary, but it was rotated so
that the copper wires were no longer parallel, as shown in Figures 21 through 23.
Changes in Distance for Altitude (Meters)
0.6
0.5
0.4
0.3
0.2
0.1
0.0
1
2
3
Version 1
4
5
Version 2
Figure 21. Trials done for altitude. The various changes in altitude recorded as maximums for each design.
Average Change in Distance for Altitude
(Meters)
0.6
0.5
0.4
0.3
0.2
0.1
0.0
1
2
Figure 22. Averages for altitude. The averages for the maximum altitudes for both versions.
Golf Ball Location 24
AVG
1
2
0.40
0.24
STDEV
0.08
0.05
%RSD
21.32
21.15
Figure 23. Maximum altitude technical results. The average, the standard deviation, and the
robust standard deviation for altitude.
Golf Ball Location 25
Data Analysis and Discussion
As shown in Figure 16 the average distance the golf ball could not be detected from was
97.97 m for Design 1 and 109.35 m for Design 2. The standard deviation, shown in Figure 17,
was 11.15 and 7.41 respectively, which means that the data for Design 2 was more consistent.
The robust standard deviation, or %RSD, was 11.39 percent for Design 1 and 6.78 percent for
Design 2. If the %RSD is greater than ten percent, then the data is not precise. That was the case
for Design 1, but Design 2 was highly precise.
As the maximum angles were being tested, interference was occurring at the football
field. There were a set of metal bleachers that would make the volume of the receiver increase
whenever the antenna was pointed in that direction, no matter where the golf ball was. If the
antenna was kept so that the wires were all parallel to the ground, inconsistent signals would
occur. More testing was commenced at the author’s house, where metal cars would increase the
volume. This was only done for Design 2.
When the antenna was turned sideways, the signal in the headphones would come in
clearer. If the device were rolled in a 90° clockwise and counterclockwise motion, so that the
antennas were perpendicular to the ground, it was hypothesized that the maximum angle readings
would decrease, since there is less room for error. The average angle to the left for a
counterclockwise motion was 20.15° and 29.06° for a clockwise turn. The standard deviation was
5.98° and 4.41° respectively, which is a high range. The %RSD was 29.70 and 15.18,
respectively, which show low precision. This was because of the metal car and nearby trees and
houses, which the latter caused reflection.
The last thing tested was a change in parallel altitude. The transmitter and the antenna
were initially at the same height off the ground, and the antenna was pointing towards the
Golf Ball Location 26
transmitter. The transmitter was moved, and the results were recorded, as shown in Figures 22
and 23. This was done for both versions.
The average for Design 1 was 0.40 m and 0.24 m for Design 2. The standard deviation
was 0.08 m and 0.05 m respectively. The %RSD was 21.32 percent for Design 1 and 21.15
percent for Design 2, meaning they both had low precision, and they have a trend.
Compared to other studies, these results would be poor, because the real manufacturers
would not sell their product. Their ranges are much shorter, which allows for easier testing. The
amount of g-force calculated could be off a little, so if it were slightly greater than it was
actually, then there could be potential danger for the chip.
Golf Ball Location 27
Conclusion
A location device was engineered successfully. The maximum distance the device would
read was what was expected. Its directionality could have been better, which was due to the high
amount of reflection and interference. It emitted higher volume as the device was pointed in the
general area of the transmitter. The transmitter was not put into the golf ball, so there was no way
of knowing if it would have survived 3866.3N of force.
Golf Ball Location 28
Limitations and Assumptions
The location device needed to be accurate, as well as inexpensive. As a result, an
inexpensive plastic casing was used to cover the receiver. The project cannot be used during an
official golf tournament because some consider it cheating, especially if the tournaments are
timed.
Only one brand (Wilson) was used for testing, so that the results would be consistent. The
core was completely filled in with black composite material, whereas older golf balls usually
have a small rubber ball in the middle. It was assumed that those golf balls would not be as
reliable as the fully composite ones because a change of mass in the rubber ball would be harder
to recover and balance the weight. Only one ball would be synced at a time, so if the circuit
board snapped, a new detector would need to be made.
The actual size of the circuit board made it difficult to fit in the ball. The liquid metal
worked well as filler. The inner material could not be dug out with ease, so the ball could not be
closed with the transmitter in it. It was assumed that it needed to have a mass of 46g and a
weight of 0.4508N, the standards for a ball. If the force of impact on the ball far exceeded
3866.3N, the ball and/or the chip could break.
To minimize costs, replaceable batteries in the golf ball and the device were used. If the
batteries in the ball died, then the whole ball would need to be taken apart.
Throughout the testing, interference occurred. One source was anything made of metal,
such as cars. This caused receiver to emit sounds, even when it was not pointed towards the ball.
Wind was another source of error. As the waves traveled, the wind was 27.36km/h. When both
the transmitter and the receiver were placed flat on the ground, random low-pitched noises would
occur, most often at the time of wind gushes. A third source is the surface area of obstacles. The
Golf Ball Location 29
thicker they were, the harder it was to find the ball. Partially as a result of this, reflection would
occur, where the sound reading was the same, even at largely different angles.
The maximum distance, height, and rotational angles were about 109.35m, 0.24m, and
24.61°, respectively.
The 4.34Mhz antenna had directional limits, so the sounds emitted would not be
extremely sensitive to change in direction. If the location device were dropped and the inner
components broke, or if water were somehow to touch the circuitry, then the ball could not be
located.
It was assumed that the model mimicked reality. The device is based on other golf ball
location devices and methods. It is similar to the Prazza Golf Ball Finder, but it emits a sound
when it is pointed in the direction of the ball. The design is different, however, because the
Prazza Golf Ball Finder does not have an antenna. The antenna is directly based off a Yagi
antenna.
The testing methods performed were partially assumed to mimic real world testing. The
manufacturers do test for maximum distances, maximum angles, and for sources of error.
However, they would have an open area to do so, and there would be many more trials.
Golf Ball Location 30
Applications and Future Experiments
The set could be used during a normal golf game, saving time and effort spent looking for
balls. However, it cannot be used during a tournament. According to two workers at Pleasant
Valley Country Club in Sutton, using any location device is cheating and is against the Official
Rules of Golf (personal communications). The testing could be done indoors at a large arena,
where there is neither wind nor other interferences.
A future experiment would be to have the transmitter be built in the ball, instead of
having the ball be cut in half. This would make the results more reliable because the mass,
density, and weight of the ball would be the same. The batteries for the apparatus could be solarpowered, saving energy. The handle on the antenna could be built with grooves to maximize
comfort. Syncing multiple balls to the finder by Bluetooth would be more convenient than
always carrying the same ball.
If GPS technology was used, it would take much less effort to search for the ball. Recent
progression in science regarding global positioning systems has enabled its usage in navigation.
When GPS first came out, it was rare and expensive. The cost has been lowered ever since it has
become one of the most widely used navigation apparatuses. GPS works by having satellites
orbiting the Earth send signals to a GPS receiver, which will return the signals. The signals
contain information about the location and time. All GPS devices, such as the ones in Figure 5,
transmit their data at the same time. The devices are accurate, and most will send the user within
ten meters of their destination (Griffin, 2011).
Golf Ball Location 31
Figure 5.GPS receivers. There are several different types of GPS devices.
When data is received, information is displayed on the screens of the majority
(“GPS navigation device”, 2012).
A future application for the golf ball locator would be to include an LCD screen that
displays the location (latitude, longitude, and altitude) of the ball by GPS. An arrow could point
in the direction of the ball, and the distance could be displayed. The screen could either be
simple and low cost, or high quality and more expensive (U.S. Patent No. 7,054,725, 2006).
Not only could this be used by normal athletes, but also it could be used by people with
visionary problems. The ball finder could be attached to a golf cart and make the cart move to
the ball, in a year-long project. Multiple GPS handhelds are in the development stages and will
be installed into future golf carts/karts (Wa Wanjiru, n.d.).
It would be a lot of work making the cart move, because a sensing system would need to
be installed in the front (Figure 6). Automatic steering and brakes would need to be
implemented, so that the cart/kart does not run into any obstacles. P-BASIC or BASIC
programming language could be used to make the cart/kart move. Combining this and GPS
would lead to a helpful but expensive golf ball finder, as this could help people with physical
handicaps.
Golf Ball Location 32
Figure 6. White golf cart . The basic design of a golf cart/kart. The
sensing system could go where the license plate would be (“New rules
for golf carts”, 2012).
Original concepts for early navigation systems had the same premise – move by using a
map programmed into the device. It would contain an input system and would display
information regarding that information on a monitor. It would use coordinate points to move to
the final destination, and would stop if the exact point was reached, or if another point that was
very close to the original (U.S. Patent No. 4,796,189, 1989).
Finally, the antenna could be redesigned completely if the frequency of the waves were to
be raised. In the current design, the frequency is low, so the antenna’s directionality is limited.
With an increase in frequency, the directionality will dramatically increase (Figures 7 and 8.)
Golf Ball Location 33
Figure 7. Antenna with four long copper wires.
An antenna with two long directors limits the
directionality.
Figure 8. Antenna with eight short wires. An antenna
with six shorter directors significantly increases
directionality (“DIY yagi antenna for 1200MHz
(2400MHz)”, 2010).
Golf Ball Location 34
Literature Cited
Andrews, D. (2009, March 10). Computer tech support: How do circuit boards work?
Retrieved from http://www.youtube.com/watch?v=gUzyd4klMQk
Bodamer, T. (2012). Golf ball finders: How they work. Retrieved from http://golftips.golfsmith.
com/golf-ball-finders-work-1445.html
Brain, M. (n.d.). How radio works. Retrieved from http://electronics.howstuffworks.com/
Brown, D., Burch, M., Krull, J., and Pemble, C. (2006, May 30). U.S. Patent No. 7,054,725.
Washington D.C.: U.S. Patent and Trademark Office.
Circuit boards / PCB. (n.d.). Retrieved from http://www.reatechnologies.com/circuitbrd.html
DIY yagi antenna for 1200MHz (2400MHz). (2010). Retrieved from www.mictronics.de/
Elert, G. (2001). Force of a golf club on a golf ball. Retrieved from http://hypertextbook.com/
facts/2001/EmilyAccamando.shtml
Eren, H. (2006). Wireless sensors and instruments: Networks, design, and applications. Boca
Raton, FL: CRC Press.
Goetz, K., Kerkering, H., Sanderson, M., and Stovall, J. (2012, June 22). Lesson: Marine animal
tracking. Retrieved from http://www.teachengineering.org/
GPS navigation device. (2012). Retrieved from http://en.wikipedia.org/wiki/
GPS_navigation_device
Grass, Jennifer. (2011). Golf ball GPS. Retrieved from http://www.radargolf.com/news/
articles/072007.asp
Gray, J. (n.d.). KLP / KLPA module walkthrough. Retrieved from http://www.sparkfun.com/
datasheets/RF/KLP_Walkthrough.pdf
Griffin, D. (2011, June 26). How does the global positioning system work?. Retrieved from
http://www.pocketgpsworld.com/howgpsworks.php
Hewes, J. (n.d.). Circuit symbols. Retrieved from http://www.kpsec.freeuk.com/symbol.htm
How does a CB radio antenna work?. (n.d.). Retrieved from http://electronics.howstuffworks.com/
Industrial and scientific. (n.d.). Retrieved from www.amazon.com/
Golf Ball Location 35
Itoh, T., Nakayama, O., and Ueno, H. (1989, January 3). U.S. Patent No. 4,796,189. Washington
D.C.: U.S. Patent and Trademark Office.
Kelley, B. (2012). Hazard. Retrieved from http://golf.about.com/od/ golfterms/g/Hazard.htm
Mishra, G. (n.d.). Quantum Dots. Retrieved from http://wolfweb.unr.edu/homepage/
bruch/Phys461/6.pdf
New rules for golf carts. (2012, June 26). Retrieved from http://www.cityoffollybeach.com/
new-rules-for-golf-carts/
Prazza golf ball finder. (n.d.). Retrieved from http://www.amazon.com
Quantum dots - what are quantum dots, why are they important and what applications are they
used in? (2005, August 25). Retrieved from http://www.azonano.com/
Reply 1: How does a laser detector work? (2004, March 9). [Comment on how a laser detector
works]. Retrieved from http://www.airliners.net/aviation-forums/non_aviation/
read.main/516608/
RWS-371 RF module series. (n.d.). Retrieved from http://content.solarbotics.com/products/
datasheets/receiver_module_data_sheet.pdf
Simple 430-mhz 4-el yagi for mountains. (2003). Retrieved from
http://www.antentop.org/004/files/434.004.pdf
TWS-BS RF module series. (n.d.). Retrieved from http://ecee.colorado.edu/~ecen2270/
components/TWS-BS-3_433.92MHz_ASK_RF_Transmitter_Module_Data_Sheet.pdf
Wa Wanjiru, M. (n.d.). GPS golf; How can a GPS system work with the game of golf? Retrieved
from http://www.streetdirectory.com/travel_guide/115686/gaming/
gps_golf_how_can_a_gps_system_work_with_the_game_of_golf.html
Golf Ball Location 36
Acknowledgements
The author wished to thank all of his teachers for their support and interest in his project.
He praises his advisor, Mr. David Ludt, for giving him confidence. He would like to thank the
students in his advisory, including Nicholas Gigliotti, Andrew McAffee, and Lambert Wang for
their excellent suggestions and for helping him set up interviews. He expresses gratitude towards
Dr. Judith Sumner for continually urging him to do better, and Mr. Thomas Regele for
organizing the science fair forms.
Much appreciation goes towards the author’s parents, for their support and willingness to
help whenever they can. He would like to thank his WPI mentor, Dr. Fred J. Looft, who guided
him through the steps to engineer his project. His advice, assignments, and patience were much
appreciated. He would also like to thank a senior Mass Academy student, Ryan Fletcher, for
talking to him about the early stages of the author’s project.