Chapter 2

CONCEPTUAL FRAMEWORK

This chapter presents the prior arts, review of related literature and related studies

concerning the design of a Personal Safety Gadget Using Bluetooth Technology and

Android-Based Application. This serves as a source of ideas and basis in the

conceptualization of the study particularly on the functions of the device as well as the

materials used for its construction. It also includes project concepts, conceptual model,

conceptual framework and the operational and technical definition of terms.

Prior Arts

Wearable Multi-Sensory Personal Safety and Tracking Device

The present invention by Shah, T.G. et al is a wearable, multi-sensory, personal

safety and tracking device which predicts danger by sensing changes in voice, pulse,

emotions, impact, motion of the wearer and the device state. In emergency situations, the

device triggers SOS, alarm, electro shock, pepper spray and starts capturing images and

audio recording for the safety of the wearer. For keeping a track of the wearer, the device

connects to the internet using GPRS and sends the images clicked, the sound recorded

and the GPS and GSM coordinates to the rescue team for gaining help for the wearer if

needed. In the present invention, various technologies are integrated into one single

wearable device thereby eliminating the need for purchasing and carrying multiple
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devices like pulse monitor, motion monitor, phone, camera, GPS module, self defense

tools, etc. thus saving money and providing comfort to the user.

Safelet

As with many wearable devices that focus on safety, a Safelet, as shown in Figure

1, was designed with speed and convenience in mind. The bracelet has two buttons on the

side that users can press to send a message to contact within a Guardian Network. If the

situation is one of high danger, friends and family members who see the alert can

automatically call an emergency number like 911 from within the app. The smart bracelet

also syncs with the user’s mobile phone to start recording audio.

Source: www.safelet.com
Figure 1. Safelet

React Mobile Sidekick

With the React Mobile Sidekick panic button, you’ll never have to walk home

alone. This Bluetooth panic button and personal safety app allows you to get help fast

when you need it with just one click. Simply press the button, as shown in Figure 2, and

Source: www.reactmobile.com
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the contact of your choice will be alerted that you need help and will be sent your GPS

location. The React Mobile Sidekick can easily be attached to key chains, backpacks and

purses.

Source: www.reactmobile.com

Figure 2. React Mobile Sidekick

Design and Development of Women Self Defense Smart Watch Prototype

Shreyas R.S, et al. (2016) designed a smartwatch prototype that deals with a quick

responding, cost protection system for an individual and especially for women using

which a woman in anguish can call for help just with the press of a button on this smart

gadget. It has the ability to help women with technologies that are embedded into a

compact device. It has the potential to help women with technologies that are embedded.

It has a control button that will be used by women to inform nearby police when they are

in distress. This watch directly gets connected to the satellite through GPS when
 10

activated. Then the location is transferred through the GSM, it also contains a shock

mechanism to produce non-lethal electric shock in emergency situations to deter the

attacker.

Security System

A security system designed by Sallie Mitchell Floyed, comprising a pocketable

alarm device having a receiver, antenna and a noise generator and a separate wearable

trigger device having a switch or button, a wireless transmitter and an antenna; wherein

the trigger device comprises attachment means for detachably securing the trigger device

to a person’s body or clothing with use of a wrist strap, clip or a cord and wherein the

alarm and trigger devices are each battery powered using rechargeable batteries charged

via an electrical port, and the switch of the trigger device is operable so that the trigger

devices sends a signal wirelessly using Bluetooth (RTM) technology to the alarm device

to produce a sound by the noise generator of at least 100dB. The noise generator is a

speaker or a compressed gas system and the alarm is arranged to sound for a pre-

determined period of time.

Safer

Figure 3 shows a subtle smart necklace from Leaf Wearables that looks like a

regular piece of jewelry. The necklace connects to your phone over Bluetooth and sends

SOS alerts with your whereabouts to friends and family if tapped twice. There’s also a
 11

90dB buzzer that acts as an alarm to alert those nearby that you’re in danger. When

you’re travelling, you can also use the necklace to share your location with your chosen

contact.

Source: leaf-wearables.myshopify.com
Figure 3. Safer
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Nimb

Nimb is a wearable safety device in the form of a sleek and subtle ring as shown

in Figure 4. Nimb tracks your location and can send an alert to friends, family members

and emergency services if you’re in danger. Once the distress button is pressed, Nimb

connects with your smartphone to send distress signals to the contacts of your choice.

There’s even a hidden recording feature to capture audio – this can be a useful source of

evidence should anything serious occur.

Source: http://www.nimb.com/
Figure 4. Nimb

Wireless Personal Safety Device

A personal protective device invented by Scully, J.T. et al is combined with a

cellular telephone. Activation of either device causes activation of the other device.

Activation is achieved by a switch or voice command. Upon activation, a message asking

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for assistance at the present location is sent to a previously agreed upon emergency

contact. The smartphone also starts both audio and video recording, which are also part of

the data sent to the emergency contact person or service. Additionally, the personal

protective devices are integrated into a unit that may combine such items as a protective

spray, Taser, strobe light, dye pack, siren and other deterrent technologies to ward off

would-be attackers. These devices are integrated into a hand held unit that can be

unobtrusively worn or carried in a purse or pocket. An optical safety device is included to

protect the user from a potential assailant approaching from rearward.

Personal Safety System with Wearable Electronic Gadget

The inventors Vidhyotma, et al have designed a light weight, adjustable,

waterproof and eco-friendly wearable gadget to make women feel safe and secure. It

includes a three button triggering system, an alarm, a camera recorder, tracking system

and emergency voice call/message system Therefore a control unit, RF receiver and

transmitter, a video recording system, GSM and GPS system, cloud computing system,

siren system, self-defense (pepper spray), switching and triggering system are essential

components of the gadget. Pressing first button allows pepper spray to leak from the

container and help the user to escape. On press of second button, the pre-recorded voice

call/messages along with person’s location is send to the helpline (1091), also to the

authenticated guardian or friend and the video starts recording and is transmitted over

cloud for future help in investigation. A siren starts to blow thus, alerting the nearby

people for immediate help.

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The Personal Safety Gadget Using Bluetooth Technology and Android-Based

Application uses the existing modern technology to develop a hand-held device that

communicates with your smartphones true Bluetooth Technology. It sends SMS with pre-

determined messages, GPS location and updates to your emergency contacts. It

automatically records audio, and utilizes your smartphone’s features in order for the

device to be more compact and smaller in size.

Revolar

From a distance, Revolar looks almost like a small garage clicker like in Figure 5.

But this wearable safety device easily clips onto key chains, backpacks and purses. When

pressed twice, Revolar sends a ‘yellow alert’ to designated contacts; they receive a text

message with the user’s location and a message saying the user feels unsafe. A triple-

press sends a ‘red alert’ which indicates the user is in need of serious help.

Source: https://revolar.com/
Figure 5. Revolar
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Review of Related Studies

The studies that are presented are in some way related to the project under study.

The following information comes from different sources that may help in the

development of the project.

Personal Safety Mobile Notification System

The inventors Saigh M. M., et al stated that in described embodiments,

a system establishes a perimeter around an area, and mobile devices within the

established perimeter communicate with a server that provides and collects personal and

asset safety information. The provided information might enable users associated with

the mobile devices to plan actions or take routes based on a given criterion, such as a

safest route, through display on the mobile device. The collected information from

the mobile device might be location, emergency event, environmental factors, sensor

information and the like, which might then be communicated to users and/or

administrators of the system. Location information, such as through global

positioning system (GPS), might provide tracking of mobile devices and users or assets

associated with each mobile device. GPS functionality associates latitude, longitude and

elevation (X-Y-Z coordinate axis) data with the collected and provided information.
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A Mobile Based Women Safety Application (I Safe Apps)

Archana Naik et al. (2015) proposed an app, in which a single click of SOS sends

a message containing the location and/ or audio-video call to the guardian number. At

receiver touch the location URL in the message to view it in the Google Map. It also

provides different help tools like First-Aid help, Fake Call Help and video call. The First-

Aid help tool provides the help on various health issue problems occurred at an accidental

or emergency situation during the night time. First aid help for various problems are as:

unconscious and not breathing, choking, bleeding heavily, burns, heart attack, diabetes

etc. The Fake call help to escape from the meetings-parties at a time when women start

feeling uncomfortable and think that, ―if someone calls me then I can leave this place‖.

Fake call rings tone same as that of normal incoming call ring and once call accepted it

stop ringing. It also supports Fake Hang Up option. The guardian contacts are by-default

for this app, but it able to search the cops, firemen, hospitals contacts nearby to your

location. It also sends the audio-video recording via Email-Gmail of emergency situation

taken by the user where user unable to speak or tell the circumstances.

Security and Public Safety Application for a Mobile Device

In a plurality of described embodiments as stated by Dan Kerning, various

modules of an application for a client device may operate to enhance personal security for

an individual user, as well as public safety in general. A Blue-Phone-in-Pocket (bPip)

module operates comparable to, but more effectively than, the traditional college campus
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blue light phone. When the user of the module toggles a button on the GUI of his/her

smartphone, the App may instantly record and transmit key information to a command

center, which operates to provide assistance to the student, at their current location,

without requiring the student to relocate to one of the tradition blue light phone fixtures.

A tracking module permits the student or other user to be tracked by his/her device until

safely reaching a travel destination. The person may trigger an alarm if endangered

during the trip, which may prompt a respond from local law enforcement, and other

assigned individuals.

Safety System Utilizing Personal Area Network

William Richard Kirkpatrick III et al. (2015) designed a communication system

that revolves around a hardware device which uses Bluetooth Low Energy technology

and a wireless BLE connection to communicate with a partner application on a separate

platform. The user can register the device with the application wirelessly by putting it

into an advertising mode and allowing it to be recognized by the application. This

connection process will be done either automatically or manually. The user can then (via

button press or other hardware input) use the BLE connection to send a signal from the

device to the application. When the application receives this signal, it initiates a specific

action. Examples include (but are not limited to): automatically sending a text message,

making a distress call to a remote server, and invoking the platform to run additional

programs or services.
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Review of Related Literature

This part of the chapter shows existing information related to the topic of the

study. The following information comes from different sources that may help in the

development of the project.

Android Application

According to www.techopedia.com (2018), an Android Application is a software

application running on the Android platform. Because the Android platform is built for

mobile devices, a typical Android Application is designed for a smartphone or a tablet PC

running on the Android OS.

Figure 6. Android Operating System

Global Positioning System

GPS, according to www.techterms.com (2018), is a satellite navigation system

used to determine the ground position of an object. The GPS system includes 24 satellites

and each GPS satellite broadcasts a message that includes the satellite's current position,
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orbit, and exact time. Three satellites are required in order to determine a receiver's

location, though a connection to four satellites is ideal since it provides greater accuracy.

Figure 7. Global Positioning System

Vibration

According to www.hsa.ie (2018), vibration means rapid movement to and fro or

oscillating movement. Vibration motors are widely used in a variety of applications

including cell phones, handsets, and pagers, and so on according to www.egr.msu.edu

(2013).

Figure 8. Vibration
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Cancellation

According to www.dictionary.cambridge.org (2018), cancellation is the act of

deciding that an organized event will not happen or of stopping an order for something. It

is a situation in which something that has been arranged is stopped from happening.

Figure 9. Cancellation

Short Message Service (SMS) Notification

As stated in www.twilio.com (2018), SMS Notifications are out-of-band text

messages sent in response to events or transactions which occur somewhere else. While

often used as a marketing tool to increase the percentage of returning visitors, SMS

notifications are very useful for organization and public safety purposes as well.

Figure 10. Short Message Service

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Video Recording

According to www.mnemonicdictionary.com (2018), a video recording is a

recording of both the visual and audible components (especially one containing a

recording of a movie or television program).

Figure 11. Video Recording

Precision

As stated in www.merriam-webster.com (2018), precision is the degree of

refinement with which an operation is performed or a measurement stated. It is also the

level of agreement of a particular measurement with itself when it is repeated according

to www. dictionary.cambridge.org (2018).

Statistical Tool

The statistical tool used is T-test for Correlated Samples. As stated in Statistics

Made Simple by Antonio S. Broto (2nd ed., 2006), the T-test for correlated samples is used

when comparing the means before and after treatment. It is also used to compare the
 22

means of the pretest and the posttest. The decision rule is if t-computed value is greater

than or beyond critical value, reject Ho.

Formula in Solving T-test for Correlated Samples:

D
t=

√
2
(∑ D)
2−
∑D n

n( n−1)

Where:

D - the mean difference between the pretest and the posttest

ΣD2 - the sum of squares of the difference between the pretest and the posttest

ΣD - the summation of the difference between the pretest and the posttest

n - the sample size

Arduino Nano

According to www.farnell.com (2018), an Arduino as shown in Figure 12. The

Arduino Nano is a small, complete, and breadboard-friendly board based on the

ATmega328 or ATmega168. It has more or less the same functionality of the Arduino

Duemilanove, but in a different package. It lacks only a DC power jack, and works with a

Mini-B USB cable instead of a standard one. The Nano was designed and is being

produced by Gravitech.
 23

Source: www.nuttyengineer.com

Figure 12. Arduino Nano

Smartphone

According to www.whatls.com (2018), a smartphone as shown in Figure 13 is a

cellular telephone with an integrated computer and other features not originally

associated with telephones, such as an operating system, web browsing and the ability to

run software applications.

The following are some of the other key features of a smartphone:

 internet connectivity;

 a mobile browser;

 the ability to sync more than one email account to a device;

 embedded memory;

 a hardware or software-based QWERTY keyboard;

 wireless synchronization with other devices, such as laptop or desktop computers;

 the ability to download applications and run them independently;

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 support for third-party applications;

 the ability to run multiple applications simultaneously;

 touchscreen;

 Wi-Fi;

 a digital camera, typically with video capability;

 gaming;

 unified messaging; and

 GPS -- global positioning system

Source: www.xda-developers.com

Figure 13. Smartphone

HC-O6 Bluetooth Module

According to www.sgbotic.com (2016), the HC-06 as shown in Figure 14, is a

class 2 slave Bluetooth module designed for transparent wireless serial communication.

Once it is paired to a master Bluetooth device such as PC, smart phones and tablet, its

operation becomes transparent to the user. All data received through the serial input is
 25

immediately transmitted over the air. When the module receives wireless data, it is sent

out through the serial interface exactly at it is received. No user code specific to the

Bluetooth module is needed at all in the user microcontroller program. The HC-06 will

work with supply voltage of 3.6VDC to 6VDC; however, the logic level of RXD pin is

3.3V and is not 5V tolerant. A Logic Level Converter is recommended to protect the

sensor if connect it to a 5V device (e.g Arduino Uno and Mega).

Source: www.sgbotic.com

Figure 14. HC-06 Bluetooth Module

Lithium-Polymer Battery

According to www.sparkfun.com (2016), Lithium-Polymer Battery is a very slim,

extremely light weight batteries based on Lithium-Polymer chemistry. Each cell outputs a

nominal 3.7V at 1000mAh. These batteries require special charging. Do not attempt to

charge these with anything but a specialized Lithium-Polymer charger.

 26

Battery includes built-in protection against over voltage, over current and

minimum voltage. Caution should be observed when using this battery in wearable

projects. When using conductive thread, a short in the thread can create sparks and heat.

Source: www.circuit.rocks

Figure 15. Lithium-Polymer Battery

Lithium-Polymer Charger/ Booster

According to www.circuit.rocks (2017), the 5V/1A Lithium-Polymer

Charger/Booster is a no-nonsense circuit for generating one amp from a Lithium Polymer

battery at 5V. This Lithium-Polymer charger is a very economical choice that is equipped

with a simple booster circuit utilizing the PAM2401 IC, and includes protection diodes so

you can run multiple cells in series for an extra kick. While the booster circuit is in

operation, this board can draw more current the lower the input voltage, making it perfect

to deliver a strong charge in a small amount of time.

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The circuit is constructed by feeding an MCP73831 charge controller IC to the

Lithium-Polymer port, and to the input of a PAM2401 boost controller. Multiple

connection types are provided for the battery, charge source and switch to allow

flexibility of application, and two LEDs provide feedback on system status.

Source: www.circuit.rocks

Figure 16. Lithium-Polymer Charger/ Booster

 28

Source: www.elc.williams.edu

Figure 17. eTrex

eTrex

The eTrex is a six ounce, 12 channel and hand held GPS receiver. It has a built-in

GPS antenna and five user-buttons. All buttons are located on the sides of the unit,

allowing for simple, one-handed operation that won’t obstruct your view of the display. It

runs for 22 hours on two AA alkaline batteries in battery save mode. In addition to

determining your location, the eTrex creates, names and saves a location (as an electronic

waypoint) in its memory, allowing you to navigate back to this point any time you want.

And once you start moving, your GPS provides other data, like speed, direction of

movement, time and distance to destination, and more.

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Conceptual Model

The figure below shows the Input Process Output Model. The IPO model is the

block by block organization of inputs, processes, and output involved in the

conceptualization of the project:

INPUT PROCESS OUTPUT

A. KNOWLEDGE A. DESIGN

 Arduino IDE  Emergency Button PERSONAL SAFETY GADGET

 Android Programming  Rechargeable Device USING BLUETOOTH
 Basic Electronics  Software Design
TECHNOLOGY AND ANDROID-
 Electronics  Design and Dimension of
BASED APPLICATION
Communication Principles the Device Casing
 Technical Data of Modules B. FABRICATION
B. HARDWARE  Emergency Button
Assembly
 Arduino Nano
 Rechargeable Device
 Bluetooth Module
 Device Casing
 Battery Unit (Lithium
Polymer Battery) C. TEST
 Lithium Battery Charging
Board  Emergency Button Testing
 Tact Switch  Response Time of the
 Case Assembly Emergency Alert Testing
 Android Device  Cancellation of Emergency
Alert Testing
C. SOFTWARE  Accuracy of the Location
Testing
 Arduino BETA Software  Accuracy of the Android
 Android Studio Application Testing
 Rechargeable Battery
Capacity of the Device
Testing
 Full System Testing
 Troubleshooting

EVALUATION

Figure 18. Conceptual Model of Personal Safety Gadget Using Bluetooth Technology
And Android-Based Application
 30

Input
This block shows the knowledge, materials, equipment and services needed in

order to obtain the desired output of the project. Knowledge on Arduino IDE, Android

Programming, Basic Electronics, Electronics Communication Principles and technical

data of modules are essential to assure the functionality of each parts of the system.

Hardware materials such as Arduino Nano, Bluetooth module, battery unit, Lithium

battery charging board, tact switch, case assembly, and Android device are important in

fabricating and testing the designed prototype.

Process

The process starts with the identification of the problem. Gathering of data to

identify the possible causes is the second part and the last part is to come up with a

solution to the problem. The Process block presents the different procedures included in

the Personal Safety Gadget Using Bluetooth Technology and Android-Based Application.

Designing, fabricating, and testing are the three basic processes. For the designing

process, the following are included: layout planning of the emergency button,

rechargeable battery powered device, software design, and the design and dimensions of

the device casing. The fabrication process includes the assembly of the emergency

button, rechargeable battery powered device, and the casing. The last one is the testing

process. The emergency button, response time of the emergency alert, cancellation of

emergency alert, accuracy of the location, accuracy of the Android application, and

rechargeable battery capacity of the device are tested individually to assure system’s

reliability and functionality. A full system testing is also conducted after assembling and
 31

interfacing the prototype properly. Troubleshooting is done when the desired output has

not been met.

Output

After the full system testing, the output which is the Personal Safety Gadget

Using Bluetooth Technology and Android-Based Application is attained. It is a prototype

project that will be activated during emergency detection to provide safety and awareness

in security. It will instantaneously send emergency alert to the authority like the police

and the user’s trusted friends and family wherein user’s location will be tracked and

monitored. The system is also an aid to prevent forthcoming threats and crimes.

Evaluation

This part is the gathering and documentation of the assessments from respondents.

This verifies how the research project obtains a positive or negative feedback to be able

to modify or if not, suggest ideas how to enhance the project. This is based on a

questionnaire with its criteria:

1. Functionality is measured in terms of the prototype’s ability to provide

comfort and convenience to the user, the ease of operation, and its user

friendliness.
2. Aesthetics refers to appropriateness of size and attractiveness of the design of

the locking system.

 32

3. Workability refers to the availability of materials, components, and tools and

the presence of technical expertise of the proponents.

4. Durability is the quality of the design, materials used, and the workmanship of

the prototype that can withstand external factors.

5. Economy is measured by its fabrication cost and maintenance cost.
6. Safety refers to the absence of toxic materials, sharp edges and electrical

hazards.
7. Saleability refers to the prototype’s price competency, the presence of market

demand and the accessibility of the finished product to the user.

Parameters 5 4 3 2 1
Functionality Table 1. Evaluation Criteria
Vibration Feedback
Emergency Cancellation Alerts
Audio Recording
GPS Precision
All components are operational
Aesthetics
Fastened Components and neatness
Workability
Availability of the material components
Availability of the tools
Presence of technical expertise of the proponents
Durability
Weather resistance
Economy
Fabrication Cost
Maintenance Cost
Operation Cost
Safety
Absence of toxic materials
Absence of sharp edges
Absence of electrical hazards
Saleability
Price Competency
Presence of Market Demand
Accessibility of the finished product to the users
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Prior to evaluation, the operation and utilization of the project is demonstrated to

the evaluators. The test result of the demonstrations is shown to the panel as evidence of

its capability in doing what is expected of it.

The criteria for evaluation give emphasis on the project’s functionality, aesthetics,

workability, durability, economy, safety and saleability. Each criterion is rated in a scale

of 1 to 5 where 1 is poor, 2 is fair, 3 is good, 4 is very good and 5 is excellent.

7-Point Criterion

The following criterion will be evaluated by the user to determine whether the

device had reached its objective with respect to authenticity, functionality, workability,

economy, durability, saleability and safety.

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Treatment of Data

After the evaluation, the results are tabulated and interpreted. Qualitative analysis

method is utilized for the evaluation of the project in determining its acceptability and

viability.

A Likert Scale as shown in Table 2 is a method of ascribing quantitative value to

qualitative data, to make it amenable to statistical analysis. A numerical value is assigned

to each potential choice and a mean figure for all the responses is computed at the end of

the evaluation or survey. Used mainly in training course evaluation and market surveys.

The final average score represents overall level of accomplishment or attitude toward

subject matter.

Numerical Rating Qualitative Description Arithmetic Mean Ranges

5 Excellent E 4.51-5.00
4 Very Satisfactory VS 3.51-4.50
3 Satisfactory S 2.51-3.50
2 Fair F 1.51-2.50
1 Poor P 1.00-1.50
Table 2. Evaluation Criteria

Operational Definition of Terms

 35

Arduino – Arduino refers to an open-source electronics platform or board and the

software used to program it. An Arduino board can be purchased pre-assembled or,

because the hardware design is open source, built by hand.

A pre-assembled Arduino board includes a microcontroller, which is programmed

using Arduino programming language and the Arduino development environment. In

essence, this platform provides a way to build and program electronic components.

Android SDK –API 23 - provides all necessary tools to develop Android applications.

This includes a compiler, debugger and a device emulator, as well as its own virtual

machine to run Android programs. Android is primarily developed by Google. Android

allows background processing, provides a rich user interface library, supports 2-D and 3-

D graphics using the OpenGL libraries, access to the file system and provides an

embedded SQLite database. Android application consists of different components and can

re-use components of other applications. This leads to the concept of a task in Android;

an application can re-use other Android components to archive a task.

Bluetooth – is a wireless technology standard for exchanging data over short distances

using short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz from

fixed and mobile devise, and building personal area networks.

Contact Persons – the person added by the user to receive SOS message including his

current location, photos and voice recordings in cases of emergency.

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Emergency Button – is a switch pressed by the user in case of emergency to send SOS

messages that will notify authorities and contact persons.

Global Positioning System (GPS) – is a radio navigation system installed at the user’s

smartphone that allows the authorities and contact persons to determine their exact

location in all weather conditions anywhere in the world.

Lithium-Polymer Battery - is a type of rechargeable battery in which lithium ions move

from the negative electrode to the positive electrode during discharge and back when

charging.

Personal Safety Gadget – is a small tool or instrument that utilizes a messaging app in

order to notify the authority and the registered contact persons in case of emergency,

when the gadget’s button is pressed.

Reception – it is the conversion of information-bearing signals, such as those conveyed

via electromagnetic waves, into the signals of interest, such as music, images, or data.
 37

Rechargeable – is a property of a battery-operated device to be able to have its electrical

energy restored by connection to a power supply.

Short Messaging Service (SMS) – is a predetermined message sent to the user’s contact

persons and authorities.

Smartphone - is a mobile phone that includes advanced functionality beyond making

phone calls and sending text messages. It is a cellular telephone with an integrated

computer and other features not originally associated with telephones, such as an

operating system, web browsing and the ability to run software applications.

Transmission – it is the conversion of information-bearing signals, such as audio, video,

or other content, into electromagnetic waves, or another form, which is transmitted in a

form suitable for subsequent signal reception.

Vibration Feedback – is a feedback system present in smartphones that is meant to

confirm that the SOS message is about to be sent to prevent false alarm.