Beep Keep - Department of Electrical and Electronic Engineering

YOUR PERSONAL REMINDER. NEVER LEAVE YOUR THINGS BEHIND.
KIMBERLEY FOK, GUANG YANG, BIQI LIU, GEORGIOS KARAFOKAS,
YIANNIS KATSIDIARIS, RUMESSA RAJA, MAREK WOLOSZYN
1. Introduction
1
2. Feasibility Study and Design Choices
1
2.1 Market Analysis
1
2.2 Existing Competitors
1
2.3 Wireless Connectivity
2
2.4 Issues Regarding the Use of Bluetooth
3
2.5 Power Supply
4
3. Product Design
5
3.1 System Design
5
3.2 Software Design
5
3.3 Hardware Specification
6
4. Tag Design
8
4.1 General Features
8
4.2 Comparison between “BeepNano” & “BeepGoLarge
8
5. Project Management
9
6. Conclusion
9
7. References
10
8. Appendix
1125
Imperial College London
Department of Electrical & Electronic Engineering
Beep Keep
INTRODUCTION
Whatever your lifestyle, it is easy to leave something behind, and can result in serious consequences if it is vital to that
day’s task. Fortunately, with modern technology it is now possible to implement solutions to these problems. Finding
items often requires a tracking device attached to the item and a system that detects these devices in order to track their
position. A connection must be established between the system and its trackers to allow the exchange of information.
Though some of these systems already exist in the market, they are not widely used due to their exorbitant costs.
This report introduces BeepKeep, an electronic reminder system designed by studying existing devices and
technological advances which could improve its capabilities and reduce production costs. With BeepKeep people will
no longer leave their essentials behind. This report will follow the research involved, design and implementation of the
device. We pursue the objective of making small yet durable tags that will take advantage of the capabilities of modern
smart phones.
FEASIBILITY STUDY AND DESIGN CHOICES
Market Analysis
To determine the how our device would have to be implemented and compromised to meet the market expectations, we
conducted a survey on a group of 200 people. The survey was implemented online and distributed to family and friends,
who were also asked to pass along the survey link. Thus we managed to obtain an audience with a large age range and
from varied professional circles. For detailed survey results see
Appendix A.
Firstly, we wanted to ensure that our product would sell. The
survey showed that a promising 78% of the respondents said
they would purchase it, however, only 14% were willing to pay
£40 or more.
Next we needed to determine how big a device would be
acceptable to our market. Only about 60% of the respondents
were willing to use a tag that was not flat (Figure 1). As the
size of the tag is mostly dependent on the power source, we
have to investigate which is the smallest feasible design.
The survey also determined that very few were aware of the
existence of any similar products that are already on the market.
This shows that an aggressive promotional campaign will be
Figure 1: Pie chart showing the maximum
needed to launch BeepKeep.
‘acceptable’ tag size according to the survey
results.
Existing Competitors
There are currently many reminder applications available for smart phones such as ‘Don’t Forget’, ‘Reminders’ by Apple
or ‘Location Reminder’. The latter is just one of many which use GPS to incorporate a location triggered reminding
feature. However the following products incorporate systems that would directly compete with our design.
Loc8tor
Loc8tor is a UK technology company that specializes in GPS tracking devices. Their main target market is home use for
tracking children, or pets, however they have specific products for enterprise and security use. They produce a large range
of products from small trackers to large positioning systems. A product comparable to our specification is the Loc8tor
Lite. Loc8tor Lite uses an independent handset to track the tags. It is the size of a thick credit card (86x54x6mm), and uses
RFID technology to communicate with tracker tags and pinpoint their location using visual and audio cues. It uses
patented production technology to keep its tags small. The tags use two SR54 (Silver Oxide) batteries, which must be
replaced every 2-5 months. The tracking signal has a range of up to 122m in open air, depending on environmental
factors, location and the object being tracked. The typical cost for this system is £45 (tracking handset + 2 tags).
Stick N’ Find
Stick N’ Find [1] is a company that specialises in Bluetooth technology trackers for indoor navigation [2], as well as home
use. The business is divided into Consumer, Business to Business and Indoor Tracking departments that offer suitable
products for each division. The product is a small (size of a coin) tag that contains a Bluetooth 4.0 receiver and a lithium
1
cell watch battery. The user can communicate with the tags via a smart phone app, where the location of the device will be
displayed. The system is also compatible with other apps such as the ‘Maps’ so users can see the last detected location of
their tagged item. The estimated battery life is 1 year (based on 30 min per day usage) and the range is about 30m.
Although the app is free to download, each tag costs around £30.
Tile
A new device, expected to be on the market in the summer of 2014, the ‘Tile’ measures 36x36x4.2mm and is designed to
be attached to a keychain. Tile is also linked to smart devices via Bluetooth 4.0 so that lost keys could be located. The
App uses crowd sourcing, allowing other phones to detect the missing keys should they leave the 50-150 foot range of the
user’s phone and send an alert to your phone. The Tile also boasts a ‘beeping’ built in speaker, to help in finding the
items. The product requires battery changes every 12 months. Pre-order price is $19.95 for a single tag.
Hone
Hone is another system to keep track of lost keys, consisting of a tracker tag attached to a keychain that the Hone app on
smart device can activate, causing it to flash and beep. The system uses Bluetooth 4.0 to detect the distance to the device
and guides the user on a ‘Hot and Cold’ basis using light patterns displayed on the screen. The tracker tag is the size of a
car fob (54x32x15mm), has a 150 foot range and a 6 month battery life (CR2032). The device can be bought for $59.99.
The project was financed by Kickstarter pledges, with a budget of $85,426 provided by 1,132 backers.
Judging by the number and nature of the reviews for each device on amazon.co.uk, Stick N’ Find is currently the best
product on the market with an average 4 star rating (out of 5).
Wireless Connectivity
One of the most important aspects of our project is how the system will connect to its trackers. The technology used must
allow for fast, secure and low power data transmission. The main types of
types of wireless communications that can be used with smart phones are Bluetooth, NFC (Near Field Communication)
and RFID (Radio Frequency Identifications).
Bluetooth
Bluetooth has been one of the most promising wireless tranmission
systems. It communicates via radio waves but only for short distances.
An example of a Bluetooth network (piconet) can be seen on Figure 2.
It consists of a ‘master’ (M) device and ‘slaves’ (S). The master can
exchange data with many slaves, while the slaves can only
communicate back to the master and not between themselves.
Bluetooth provides a short distance connection between the devices
allowing data transfer in a spread spectrum frequency hopping, fullduplex signal at a nominal rate of 1600 hops/sec. Bluetooth can work
Figure 2: Piconets
with different bandwidths such as 2.4 GHz – 2.485GHz (unlicensed
industrial), or ISM (scientific and medical.
Bluetooth has been installed on all phones since 20001, and is therefore readily available to every person that owns a
smartphone. Furthermore, Bluetooth is more immune to noise among other wireless connections, the signal to some extent
can penetrate through solid objects such as walls and can be read in any position by the receiver. Bluetooth devices are
relatively cheap and have a low consumption of power. The technology also addresses security issues by requiring
“pairing” between devices before a connection can be established.
Bluetooth is suitable for implementing in our tags because of a good balance between advantages and drawbacks.
NFC
NFC is a low-range wireless communication technology, which allows two devices to transfer data between them through
radio frequency modulation. The most common applications of NFC technology are in contactless micropayments [3], in
mobile marketing [4] or using the phone instead of badge. NFC tags don’t require a power source since they draw power
from the detecting device while Bluetooth tags need their own power supply. NFC technology also consumes less power
in the smartphone [5]. NFC’s maximum transfer rate is 424 kbps which is significantly slower than that of other standards
such as Bluetooth (up to 24Mbps) [6]. Also, NFC works without pairing which makes it more vulnerable to hackers.
However, the biggest drawback of NFC technology is its range. The current uses of NFC involve touching the tag or
2
approaching it at a maximum distance of 10cm when Bluetooth communication can take place over 100m. This means
that this technology will not be suitable to implement in our system for tracking the tags. The technology is however
suitable to implement a registration system for individual tags that can scan them into the system directly.
RFID
This newly introduced technology can be used in various applications such as reading electronic passports and contactless
payments. It uses radio-frequency magnetic fields to transfer data. It consists of two components; a circuit that is used for
modulation and demodulation of signals (interrogator), and a tag (transponder), which has a microchip contains an
antenna that receives the radio waves from the reader. The system also includes a database where the information of the
tag content is stored. RFID works in a wide range of frequency. Both the reader and the tag must operate at the same
frequency for RFID to work. Its most significant advantage is low power draw. Currently RFID tags can have a lifetime of
over 10 years with a consumption of 100mA/h. This is very low consumption if we compare it with a normal AA battery,
which consumes 2100ma/h. Hence this application can be used for a larger range of communications2. Also its range (c.
90m) is the same as Bluetooth technology.
However a single RFID tag is very expensive (£15) and would increase the cost of the product significantly. Furthermore,
the RFID technology can be very unsecure as RFID tags respond to whoever sends a signal to them. This can lead to
unauthorized access to the user’s data. Since it is a newly developed technology, started no longer than 10 years, these
issues3 have not yet been solved.
For these reasons current RFID technology is unsuitable for our device.
Bluetooth technology, which is a form of wireless communication, was chosen for several advantages over similar forms
of communications. However, although it is an elegant approach for developing BeepKeep, it still raises certain
concerns with privacy and data protection.
Issues regarding the use of Bluetooth technology
Privacy
Many concerns may arise regarding tracking technology. The purpose of the device is to track items that are likely to be
lost or forgotten. However, in order to do users must enable their smartphone’s Bluetooth connectivity. Any Bluetooth
device can identify nearby devices and track their location, if they are ‘visible’ to other devices. This means that the
device and also the Bluetooth tags will be traceable to others [7] as long as they stay within the range of the handheld
tracking them. In the case of a smartphone, it will transmit its signal at 2.4GHz and will be visible to peripheral Bluetooth
devices. As a direct result of Bluetooth tracking, user privacy becomes an issue. Using Bluetooth to track people can be
considered an invasion of their privacy. Most legal systems allow parents to track their children for safety, but in general
tracking people is not allowed without consent. There are already a few products (e.g “Zonith Indoor Positioning System
[8]”) available on the market for consensual tracking of the employees in a workspace. The products main purpose is to
locate lone workers in case of emergency e.g. when they lose consciousness, for security personnel to call back-up or even
in aggressive working environments, for protection.
Of course Bluetooth tracking is limited by it’s own technology. The maximum distance it can work properly is up to 100
metres9 (300 feet) or less if it encounters solid objects such as walls, which doesn’t make it a big concern without using
GPS.
A lot of existing and developing projects are using Bluetooth technology to work properly with peripheral devices or to
improve tracking through closed space. This application of Bluetooth is desirable as long as it doesn’t violate human
rights to privacy and keeps exchanged information encrypted.
Data Protection
Since the introduction of Bluetooth technology mobile devices have been able to send and receive data by tracking other
mobile devices with the same technology [9]. However, this technology can endanger its users because it deals with a lot
of sensitive, private data. The technology can be used to access the device that is using it to connect to other devices or to
intercept the information transported between these devices.
There are 3 distinguishable types of Bluetooth hacking.
Bluejacking is the most “harmless” method of abusing Bluetooth connectivity. The hacker can use the business card
feature to send messages (within the Bluetooth range) to a visible mobile device [10]. Anyone with Bluetooth enabled is
2
3
(RFID Security, 2008) http://www.infosec.gov.hk/english/technical/files/rfid.pdf
(“Problems with RFID”) http://www.technovelgy.com/ct/Technology-Article.asp?ArtNum=20
3
vulnerable to annoying or offensive messages. However it is not so harmful because it cannot access any data on the
phone. Also, users can avoid this type of attack by setting their mobile device to ‘hidden’ or ‘invisible’.
Bluesnarfing targets the user’s information, and can affect them even if their mobile device is set to ‘invisible’. This type
of hacking works by using specialised software to send information requests to the user via the Bluetooth OBEX pushprofile. However it takes time because the attacker has to guess or be able to track the mobile device’s name.
Bluebugging is the ability to take over the user’s phone after accessing it via one of the previous methods. The hacker
can then corrupt or steal personal data. Fortunately most modern devices are not vulnerable to this problem.
Despite Bluetooth not being an entirely secure method of connection, simple steps can be taken to protect the users from
being vulnerable while using it. The user can reduce the risk by making devices undiscoverable so the hacker cannot see
them. Also, users are strongly encouraged to change their device name sand use strong PIN’s between any transfers of
data. There is lots of software created in order to prevent hackings and can be downloaded and installed very easily.
Power supply
The power supply is used to turn the Bluetooth connection of the tag on. Since the Bluetooth installed operates typically
1.8V~3.6V4, thus, the minimum voltage supply must be 3.6V. The tag should be designed to be small and light like a
‘sticker’ to attach to items. However, the type of power supply dominates the size of the tag since the size of the Bluetooth
that built in is (5x5mm) is significantly smaller. The lifespan of the power supply is expected to last at least a year
provided the tag might be ‘on’ about 30 minutes per day5.
We can estimate the life-time of a battery:
Battery lifetime (h) = Battery capacity (mAh) / Average current consumption (mA)
The limitation of using the batteries to power up the tag’s
Bluetooth is the life span of the batteries. This is because the
Bluetooth 4.0 operates at different modes requiring different
supply current supplied by the voltage at short pulse widths.
Research shows that high voltage supply at short pulse will
have sudden voltage drop across the ESR (Equivalent Series
Resistor) of the battery. A sudden discharge of the battery
will shorten the battery’s lifespan.
The ESR of super capacitors is much lower than the ESR of
normal batteries. Thus, the voltage drop across the parallel
connection is much less leads to greater usable voltage which
we would like to have.
Below is a list of criteria we would consider while deciding
Figure 3: Power Density of different type of power supplies
on our power supply6:
1. Rate of charging/ discharging
2. Size
3. High and constant output voltage
4. Energy Density (Figure 3)
To meet the requirements we can use one of two combinations of
super capacitors and batteries.
Super capacitor combine with the batteries
Current tags are mainly powered by coin cells such as the CR2032 that
Figure 4: Parallel combination of Super
has a nominal voltage of 3.0V (from CR2032 Datasheet included in the
Capacitor and battery.
Appendix D). By connecting the coin cell parallelly with the super
capacitor (Figure 4), the power management of the power supply is improved and will extend the life span the tag. A
diagram of the differences of the usable voltage against the current pulse width has shown that the parallel connection’s
4
5
(Nordic Semiconductor Nrf8001 Single-chip Bluetooth ® low energy solution Product Specification 1.2 )
(StickNFind App Integrates Map Application, 2013)http://blog.sticknfind.com/sticknfind-app-integrates-map-application
(Sticknfind, 2014) https://www.sticknfind.com/sticknfind.aspx
6
(Paper) Design Advantages of Solid State, Batteries versus Supercapacitors
4
dropout voltage is smoothened by the super capacitor, thus extending the duration of voltage drop across the coin cell
(Figure 5).
Super capacitors:
Figure 5: Useable Voltage vs. Current pulse width showing the difference between the configurations
A combination of the energy storage properties of the batteries with the power discharge characteristics of capacitors, also
known as Electrochemical Double Layer Capacitors (EDLCs).
It has higher capacitance and energy density than normal capacitors. A more in depth introduction on the super capacitor
will not be discussed here. The report will only emphasize why it will be a good choice to combine with the battery.
Research shown that using super capacitors has the following advantages :
1. Shorter duration of discharge and charge than the batteries
2. Provide high peak power (low ESR- Equivalent Series Resistor).
3. Meet environmental standards , i.e. no leakage of chemicals
4. Operates at extreme temperature. The super capacitor we chose is Cellergy’s CLC03P070L1 (CLC: Low Leakage
Line Charge, used to offer low leakage current for extra-long battery life without compromising on power
density).
The size is 17x17.5 mm2 double super capacitor, which is an optimum for larger designs. This connection will allow the
power supply has a longer lifespan than using a single coin cell. Furthermore, the high rechargeable ability of using super
capacitor which ensure a sustainable power source for the tag. A general engineering characteristics of this super capacitor
is included in the Appendix G.
Theoretically, a fully charged super capacitor has 3.5V, the time taken for it to discharge is calculated as below:
0.07F × 3.5V = 0.245C, (capacitance of CLC03P070L1 is 70mF)
∵ 1C = 1A × 1s (In the SI system) ⇒ 3600C = 1A × 1h
⇒ 0.245C = 68μAh-1
⇒ 68μAh-1 / 0.6μA = 4.7 days
This shows that the super capacitor has a significant short discharge rate compare to a normal 3.0V coin cells might take 6
months or more to discharge. The super capacitor will discharge/ charge faster compare to the coin cell based on different
operating modes of Bluetooth. Hence, this result in a greater change in the current through the super capacitor compare
through the coin cell. By minimizing the change of current/voltage across the coin cell, we can prolong the cell’s lifespan.
Parallel combination of coin cell CR20327
Since the coin cells are already applied into the current available devices in the market, we would not do a great detail on
this type of power source. We have included the datasheet of CR2032 in the Appendix D. Research shown that by
connecting the coin cells in parallel i.e. 2 coin cells increases the life span by 400% compared to using one coin cell. The
research state that the battery’s life span is dependent on the current is drawn from it. Since the Bluetooth 4.0 operates at
different modes which draw different currents, it has been shown that different current drawn affects the battery life time
significantly. The results of the report convince us that this approach would be feasible. However, parallel combination of
the two coin cells result in a more bulky size of our tag, which might not be preferred by our consumers. It will be at least
doubling the size of the tag. Therefore, we introduced a few sizes of the tags with different lifespans of the power supply
as the alternative solutions.
7
(Shahriar Emami, 2013) IEEE 24th International Symposium on Personal, Indoor and Mobile Radio Communications
5
PRODUCT DESIGN
System Design
The system requires a platform which will receive information from the tracking tags in order to help find the user’s
items. Instead of building our own platform, we decided to use the capabilities of the smart phone. Smart phones seem to
have become a necessity and most people carry them every day. Developing an application for a smart phone, which can
detect Bluetooth signals and send alerts, will be the most efficient solution comparing with designing our system.
Therefore, smartphone application is one essential and irreplaceable part of developing BeepKeep.
Choice of mobile platform
The four platforms most widely used, are namely iOS, Android, Blackberry, and Windows Phone. At the beginning of our
research and development, the Android platform enables us to design our product most efficiently. This is because of its
open-source feature and available code resources. Although the iOS system is used by a significant number of customers,
the iOS version of the application could not be written because we did not have the necessary development resources at
hand.
Corresponding applications will be developed if the product is commercially successful. Remarkably, Blackberry platform
has the advantage of being used by businesses, which could expand our product to new markets.
Software Design
Mobile App
The Android operating system provides built-in Bluetooth APIs (e.g. scan for devices, query the local adapter, manage
multiple connections), detailed documentation and a rich Graphical User Interface (GUI). Those modules are sufficient for
our app to be developed. Under its open ecosystem, a huge number of open-source codes are available and are free to
adapt and redevelop. It is highly possible to produce one app within a limited time period by referring existing example
codes.
The application on Android platform is designed to have several functions, including testing the Bluetooth connection,
distance estimation, and changing user settings. The basic structure is demonstrated in Fig. 6.
Figure 6: App Design
To start with, users need to add new stickers by entering sequence numbers. The number is actually the MAC address of
the Bluetooth sticker. Then, if the “Start Detecting” button is clicked, the app will create a broadcast to scan for this MAC
address and return the Received Signal Strength Indicator (RSSI). An estimated distance is displayed on screen after
comparing the RSSI value with our experimentally measured RSSI-distance data (Figure 7). The newest generation of
RSSI-Distance Data For Bluetooth 2.0
RSSI-Distance Data For Bluetooth 4.0
-30
-40
-40
-50
-50
RSSI (dBm)
RSSI (dBm)
-30
-60
-70
-80
-60
-70
-80
-90
-90
0
100
200
Distance (cm)
300
400
Figure 7a: RSSI-distance relationship (Detector is LG
Nexus 4 (Bluetooth 4.0), target is Nokia N95
(Bluetooth 2.0))
-100
0
100
200
Distance (cm)
300
400
Figure 7b: RSSI-distance relationship (Detector is LG
Nexus 4 (Bluetooth 4.0), target is LG Nexus 5
(Bluetooth 4.0))
6
Bluetooth has a better performance in terms of RSSI measurement accuracy (linear trend show in Figure 7b). The
maximum error is ±25cm. Moreover, for Bluetooth 4.0, the detection period is almost fixed (12-13 seconds).
In terms of Bluetooth API, only the discovering function is programmed. Our app does not contain any functions for
Bluetooth data transfer. The reason is that this app has to be running all the time and executing more functions will cause
cumulatively higher power consumption and shorten the battery life of both the phones and the tags. The newest version
of Android (version 4.3) contains built-in platform support for Bluetooth Low Energy (LE)8. By applying this provided
APIs, the app can discover devices at even lower power losses.
Functionality
After completing fundamental functions, a series of
optimisation [11] is carried out gradually. The user
interface has been altered several times until the desired
result of a colourful and concise, minimalistic design is
reached. The installation package has been reduced from
200kB to 55kB by redesigning and minimizing resources
(Figure 8).
If the app detects that a device is out of a user defined
range (within Bluetooth performance) it will generate a
loud Alarm to prevent the user from overlooking the alert.
Figure 8: App GUI
Logo Design
A business needs a well-designed logo which is both eye catching and memorable.
Taking our target market and the final product into account we designed a logo
which is shown on Figure 9. Keeping in line with our desire to be memorable to the
consumer, we settled on the name ‘BeepKeep’ due to the significance of each
word: ‘Beep’ indicates that our product will generate an audible alert; ‘Keep’
suggests that this Bluetooth reminder will help users to keep a hold of their
belongings. The logo is built based on the image of a bee, partly because ‘bee’ is a
syllable in ‘beep’, but also because bees live as a strict society and are responsible
for their assigned tasks. Colourful design is consistent with our multi-colour and
lively Bluetooth tags.
App Security
Figure 9: BeepKeep
logo
In order to increase the security of the system, our application does not transfer data between the tags and the user.
However, when using the tracker, the phone is still vulnerable to attacks via the Bluetooth network.
To prevent this the communication between the stickers and the mobile device that they are going to be connected to
through our application will be encrypted. Each tag will have to be paired with the device so that no 3rd party can use the
app to connect to the phone. With this protection, security issues are minimised.
Hardware Specification
A further study of Bluetooth technology was necessary to make design
choices.
There are two significant types of Bluetooth, Classic Bluetooth and Smart
Bluetooth(low energy or LE). A major difference between both is the
prior can connect to seven slaves whereas the later connects unlimited
number of slaves9 besides differs in the power consumption10. A
comparison of Bluetooth versions are shown on the Figure 10.
However, it has a smaller detectable range in comparison to the other
versions, it is sufficient to be implemented into our device since only low
data transfer rate needed. [12]
8
9
Inquiry
Active Mode
Sniff Mode
Paging
Hold Mode
Connection
Park Mode
Figure 10 Connection steps of 2
Bluetooth devices
(Bluetooth Low Energy, Google Developer document) http://developer.android.com/guide/topics/connectivity/bluetooth-le.html
(Jia Liu, Canfeng Chen, Yan Ma, Ying Xu, 2013)
10
See Appendix F
7
In order for the system to work, the smart phone and the tags must have compatible profiles11. For our project, the tag’s
Bluetooth will just transmit a set of data when it exceed a predetermine range / distance from the Bluetooth of the phone.
Hence, we will be using the LINK Loss Service (LLS)12.
When the user activates their Bluetooth, their phone will be able to detect the surrounding electronic devices that have
Bluetooth enabled. Pairing between the Bluetooth of the smart phone and these device can happen once both share the
same affinity, before they exchange data between themselves. Once pairing is successful, the user of the smart phone has
to approve via an authetication process. Once this is approved, the two media will then share their addresses, profiles,
names and store them in memory. [13] A ‘key’ will also be generated for future connections, which means the smart
phone will automatically ‘remember’ each other. 13For the general specification of Bluetooth 4.0, please refer to Appendix
E.14
nRF8001
The traditional Bluetooth device (Figure 11) maintains the
Versions
Range(m)
Speed
Power
connection between the device and the user, even if there is no
(Mbps) Consumption
data transfer. There are some modes (sleep, idle, standby) that
(mW)
allow the device to consume less current, therefore less energy.
1.2
10(1- 100)
1
2.5(1-100)
However at the active mode, the peak current is typically 252.1
10(1- 100)
2~3
2.5(1-100)
30mA which is considered to be large in the use of coin cell
3.0
10(1- 100)
24
15-20
batteries
4.0
61
1
1.5-20
Researches have recently introduced the Bluetooth Low Energy
(Bluetooth 4.0 LE) which our product nRF8001. Its advantages are
various. Firstly, the peak current during the data transfer is
typically 15mA. Typical transactions of data are within a range of Figure 11 The different modes of nRF8001 drawing
different amount of current & power consumption at
3ms. This means that with the use of our coin cell battery Cr2032
various condition
(nominal voltage 3V, 220mAh capacity) and an average
transactions of 10 reports per minute of the day (14400 reports /day), the average expected battery life will be 1500 days
or approximately 4 years. Also it has a range of 100m which is more than essential for our application specifications.
Our Bluetooth device uses different modes so that it can minimize the power consumption. When it is not used it will be
in standby mode, ready for use between connections of devices. When it is inactive over a long period, it will get in sleep
mode which reduces the power consumption (peak current reduces to 1μA). It has a high region for operating temperature
range (-40oC to +85oC).
nRF8001 Single-chip Bluetooth® low energy solution (see Appendix E)
It supports the Bluetooth LE v4.0 with low energy LLS and operating at voltage supply 1.8~ 3.6V.
Bluetooth 4.0 can be programmed to assume ‘sleep mode’ constantly and ‘wake up’ when data transmission is required.
This means that most of the time the Bluetooth draws minimum current, while detecting transmission of data regularly.
Antenna design for Bluetooth
The antenna is essential for any devices that involve the transmission of radio waves. It is used to convert electrical
current to electromagnetic waves of vice versa1. The size of the antenna has to be the same as the wavelength of Bluetooth
radio waves:
Where c: speed of light; λ: wavelength; f: frequency. fBluetooth 4.0 =2.5GHz so
= 0.12m is the size of the antenna.
In Bluetooth, there are two types of antenna: Chip antenna and Film antenna15. The prior are applied in most Bluetooth
devices whereas the latter is installed in all smart phones.
We will be designing our antenna such that it wraps around the coin cell’s circumference to ensure there is no blockage of
transmission/ receiving of signals. Thus, film antenna is preferred due to it is more flexible than using chip antenna.
However, from the above calculations, the length of antenna is significantly long. The type of antenna to be installed in
the tags is Omnidirectional Antenna3.The size of the antenna can be adjusted according to the directivity. We will focus
on the design of antenna at a later stage.
11
12
an additional protocol to define what kind of data both Bluetooth are transmitting
defines the behaviour when a link is loss between two device (Bluetooth Developer Portal)
13
(sparkfun)
(Decuir, 2014 )
15
(Jeong, 2012)
14
8
TAG DESIGN
Before starting the design process, there were several things to consider. The size of tag
should be determined by the size of hardware implemented inside, including the power
supply, a Bluetooth chip and the inner circuit. One specific design specification-the size was
taken great care of. As we will be handling very small items, the size of the hardware chips
implemented will be a design trade off. More detailed specifications, such as cost and
Figure 12: Beep Keep Tag
shape of tags, were based on the survey conducted. Though all requirements can’t be
3D model
met due to technology limitations, we tried to maintain the largest possible market. The
concept model of the tag can be seen in Figure 12.
General features:
Appearance - trendy, simple and promotional ‘Beep Keep’ tags can be a lifelong companion for some of user’s stuff, thus,
the appearance of tags should serve as a decoration as well as at the same time promote our product, by showing the logo.
We have designed 2 sizes, each with 2 colours to match the colour of the user identified item.
BeepNano
‘BeepNano’ benefits from its small size. For ‘BeepNano’ we use the smallest
possible size for the power supply: coin cell CR927. The coin cell we will be using
has to be smaller thus has a short life span. It can be easily attached to small items
such as keys and bank cards. The body of “bee” shape indicates the place of button
cell and has a diameter of 9.5mm. Fig.13 shows the size of a ‘BeepNano’ tag in
comparison with a bankcard. The tag is designed to have a white background with
the logo at centre of it.
Figure 13 A bank card with
‘BeepNano’
BeepLarge
‘BeepLarge’ is of regular size and is used for larger items. Without the limitation
in hardware size, battery can be chosen to last longer and save the effort of recharging/changing batteries constantly. The
logo however is designed with word ‘BeepKeep’ which promotes the product even better.
Structure - tidy and handy
The tags come with a lid at the top to replace the button cell.
Bluetooth address of each and every single tag is carved at the back of its lid, which makes it quite easy to set up the link
between these tags and the mobile app.
Sticker - sticky as one
We intend to use the same technology as “command strips” from 3M, which is basically a very strong sticker and the best
thing is if one day the item is no longer in use, the sticker can be easily removed, leaving no trace behind.
Make it ‘lifelong’
We use materials that have high endurance to weather and are waterproof.
Comparison between “BeepNano” & “BeepLarge”
BeepNano
BeepLarge
Bluetooth Technology
Bluetooth 4.0 LE nRF8001 (Bluetooth® low energy Connectivity IC, Active)
Range
45m
45m
Battery type
CR927(Appendix D)
CR2032
Battery Life (30min/day)
6 months
20 months
Battery dimensions (d*h, approx.) 16
9.5×2.7(mm)
20×3.2(mm)
Bluetooth dimensions
4.6×5.6×1.0(mm)17
18.1×12.05×2.3(mm)18
16
(www.batteriesinaflash) www.batteriesinaflash.com/coin-cells/cr927/new-energy-cr927-lithium-3v-coin-cell-batteriesdl927-ecr927
17
(www.global.tdk.com) http://www.global.tdk.com/news_center/press/20140212771.html
18
(www.mouser.com) http://uk.mouser.com/ProductDetail/Bluegiga-Technologies/BLE112-Av1/?qs=sGAEpiMZZMtqO%252bWUGLBzeBlUsuxvYOBGeTcfZ0yyKCA%3d
9
Uses
Bank cards, Bus passes, Keys etc.
Laptops, Pencil cases, Bags, etc.
Device Compatibility
Android devices supporting Bluetooth Smart (Nexus 5, Samsung S3 etc.)
Working Temperature
-15 to +65 ºC
Size of antenna (around cell)
59.7mm 113.7mm
PROJECT MANAGEMENT
This project is initiated by three members of the group. They are Kimberley Fok, Guang Yang and Biqi Liu. During the
team making process, the other four members join the team to form a group of seven. Kimberley Fok is selected as the
group leader via voting process among the members.
LEADER
SOFTWARE TEAM


App development
Website design
SOFT SKILLS TEAM
HARDWARE TEAM



Connections between
smart phone and tag
Power supply of the tag
Design Circuitry of the
tag





Security issues of the
communication
Ethical issues and news
Economic analysis
Market Survey
Publicity and Media
Figure 14 Divison of Tasks
The group is divided into three sub- groups to work in different aspects of the project as shown below (Figure 14). Each
sub- group consists of two members. The process of assigning members into different subgroups based on their
preferences. If each sub- group needs extra help from other members, they can just inform the leader so that the leader
will reorganize to ensure the working progress is maintained. Each group will be assigned on a specific task each week
and have to get things done by next meeting. Strict rules are set to ensure each member contributes fairly on the design
process. We created a Facebook page and Whatsapp chat group to inform members on regular meetings every Wednesday
and remind of each member’s duty of the week. If any members have suggestions on the project, they could post their
ideas via this. Weekly emails reporting the working progress to our Supervisor, Dr Lucyszyn is in charged by the leader.
If the leader encounters any problems in terms of technical and management which cannot be solved within the group, the
supervisor, will be the consultant which gives professional advice on it.
CONCLUSION
Our survey showed us that there were enough people interested in Beep Keep to move forward with this product. Based
on demands of the market we designed a tag so that it would be small and could be produced cheaply. We had to consider
several approaches to our design to try and meet this demand. We chose Bluetooth as the dominant technology, because it
is already available to almost everyone, and it’s constantly being developed to increase its efficiency and decrease its
power consumption. We decided that while super capacitors how promising solutions to problems with sources of power,
their current development is not suitable to our technology. However, by implementing a ‘’sleeping’ state in our tags, we
could increase the time the product would be able to operate for, on just watch batteries. By writing our application so as
to avoid as many privacy and security issues as possible, we were able to come up with a product that could not only be
small and fast, but also safe and respectful to its owners. BeepKeep technology is ideal for everyday users who don’t
want to clutter their minds with remembering whether they have all their belongings. Because this market is just
emerging, the growing customer base will make this product sustainable and profitable. However, what makes it a really
good investment is the promise of future technologies that could be implemented into this simple solution to make it even
more powerful. This is a technology that will not let you forget your things, and most definitely will not be forgotten.
10
REFERENCES
[1] SticknFind Support Centre. (2013, September 17). StickNFind App Integrates Map Application. Retrieved
January 11, 2014, from StickNFind Blog: http://blog.sticknfind.com/sticknfind-app-integrates-map-application
[2] Bekkelien, A. (2012, March). Bluetooth Indoor Positioning Thesis. Retrieved from University of Geneva:
http://cui.unige.ch/~deriazm/masters/bekkelien/Bekkelien_Master_Thesis.pdf[b1] Arthur, C. (2012). Apple,
Samsung, Google and the smartphone patent wars - everything you need to know. Retrieved May 5, 2013, from
http://www.guardian.co.uk/technology/2012/oct/22/smartphone-patent-wars-explained
[3] Cheng, H.-C., Liao, W.-W., Chi, T.-Y., & Wei, S.-Y. (2011). A Secure and Practical Key Management
Mechanism for NFC Read-Write Mode. Advanced Communication Technology (ICACT). Seoul: Dept. of
Information & Management, Chinese Culture University, Taipei, Taiwan.
[4] Hassam. (2011, October 24). Types Of Bluetooth Hacks And Its Security Issues. Retrieved from HubPages:
http://hassam.hubpages.com/hub/Types-Of-Bluetooth-Hacks-And-Its-Security-Issues
[5] Beattie, A. (2013, April 22). Common Methods Hackers Are Using To Crack Your Cellular Phone. Retrieved
from Techopedia: http://www.techopedia.com/2/27824/security/common-methods-hackers-are-using-to-crackyour-cellular-phone
[6] Omorogbe, P., & Sokoya, S. (2013, October 20). How to prevent Bluetooth hacking on your smartphone.
Retrieved from Tribune: http://www.tribune.com.ng/news2013/index.php/en/component/k2/item/24332-how-toprevent-bluetooth-hacking-on-your-smartphone-%E2%80%A2my-blackberry-connects-me-with-my-fans.html
[7] Kostako, V. (2008). The privacy implications of Bluetooth . Retrieved from OULU publications:
http://www.ee.oulu.fi/~vassilis/files/papers/bluetooth_privacy.pdf
[8] Kongevej, G. (n.d.). ZONITH Indoor Positioning System (IPS). Retrieved from Zonith:
http://www.zonith.com/products/ips/
[9] Bluetooth SIG. (2013). A Look at the Basics of Bluetooth Technology. Retrieved from Bluetooth:
http://www.bluetooth.com/Pages/Basics.aspx
[10]
Browning, D., & Kessler, G. C. (2009). Bluetooth Hacking: A Case Study. Conference on Digital
Forensics, Security and Law. Burlington: Champlain College Center for Digital Investigation. Retrieved from
Gary Kessler: http://www.garykessler.net/library/bluetooth_hacking_browning_kessler.pdf
Meier, R. (c2012 ). Professional Android 4 application development. Indainapolis, Indiana, U.S.A: Wiley .
[11]
Granby, J. (n.d.). What Are Some Signal Interference Issues for the Bluetooth Technology? Retrieved
from Houston Chronicle: http://smallbusiness.chron.com/signal-interference-issues-bluetooth-technology58273.html
[12]
Kiyoshi Yoshino, K. H. (2004). United States Patent No. US 6756535 B1.
11
APPENDICES
Appendix A: Survey Results
What Age Group Are You In?
Under 18
18-25
26-34
35-50
51-65
Over 65
What Age Group Are You In?
8
122
25
30
9
6
5% 3% 4%
15%
What is Your Professional Area?
Business/Finance
Education
Entertainment
Healthcare
Legal
Retired
Science/Engineering
Student
13
12
4
19
3
4
94
51
12%
61%
Under 18
18-25
26-34
35-50
51-65
Over 65
Would You Use This Product?
No
Yes
44
156
Would You Use This Product?
How Much Would You Pay for this
Product?
FREE
£20
£40
£60
Wouldn't buy
22%
20
108
23
5
44
What Size Tag Would You Use?
Flat
3D Sticker
Larger
N/A
64
73
19
44
78%
Do You Know Of Similar Products?
No
Yes
188
12
No
Yes
12
What is Your Professional Area?
Student
Do You Know Of Similar Products?
Science/Engineerin
g
6%
Retired
Legal
Healthcare
Entertainment
Education
Business/Finance
0
20
40
60
80
100
What Size Tag Would You Use?
94%
No
Yes
22%
32%
10%
36%
Flat
3D Sticker
Larger
N/A
1
actiona.setTitle("Beep Keep");
Resources r = getResources();
Drawable myD =
r.getDrawable(R.drawable.bar);
actiona.setBackgroundDrawable(myD);
BluetoothAdapter bluetooth =
BluetoothAdapter.getDefaultAdapter();
Appendix B: Android App Code Segment
BluetoothActivity.java
package com.Beep Keep.bluetooth;
import
import
import
import
import
import
java.io.FileInputStream;
java.io.FileNotFoundException;
java.io.IOException;
java.io.InputStreamReader;
java.util.Timer;
java.util.TimerTask;
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
import
android.annotation.SuppressLint;
android.app.ActionBar;
android.app.Activity;
android.app.Notification;
android.app.NotificationManager;
android.app.PendingIntent;
android.bluetooth.BluetoothAdapter;
android.bluetooth.BluetoothDevice;
android.content.BroadcastReceiver;
android.content.Context;
android.content.Intent;
android.content.IntentFilter;
android.content.res.Resources;
android.graphics.drawable.Drawable;
android.media.Ringtone;
android.media.RingtoneManager;
android.net.Uri;
android.os.Bundle;
android.os.Vibrator;
android.util.Log;
android.view.Menu;
android.view.MenuInflater;
android.view.MenuItem;
android.view.View;
android.widget.Button;
android.widget.TextView;
android.widget.Toast;
android.widget.Switch;
this.bluetooth = bluetooth;
if (dialog_int == 0 && shec == 0) {
initBluetooth();
}
// status bar notification
Uri notification = RingtoneManager
.getDefaultUri(RingtoneManager.TYPE_ALARM);
ring =
RingtoneManager.getRingtone(getApplicationContext(),
notification);
Initial(); // Switch on Bluetooth
final Button button_new = (Button)
findViewById(R.id.button_new);
button_new.setOnClickListener(new
View.OnClickListener() {
public void onClick(View v) {
startActivity(new
Intent("com.Beep Keep.AddNew"));
}
}); // create a new switch label
}
public void onResume() {
super.onResume();
pause_int = 0;
if (dialog_int != 0) {
cease();
NotificationManager nm =
(NotificationManager)
getSystemService(NOTIFICATION_SERVICE);
@SuppressLint("NewApi")
public class BluetoothActivity extends Activity {
public static final String EXTRA_RSSI =
"android.bluetooth.device.extra.RSSI";
protected static final String TAG = "Beep Keep";
// for debug use
protected static int RSSI_value = -100;
protected static int count = 0;
protected static int count_pre = 0;
protected static int time_elapse = 0;
protected String s_now = "";
protected String s_pre = "";
protected String labels = "Keys"; // will read
from the switches labels
protected String bluetooth_address = "";
private static final int READ_BLOCK = 100;
protected static int shec = 0;
protected static int dialog_int = 0;
protected static int pause_int = 0;
protected static int sensitivity_value = -90;//
will read from "sensitivity.file", set by user
final Context context = this;
String text1 = "";
String[] ss = new String[4];
Timer mTimer = new Timer();
BluetoothAdapter bluetooth;
Ringtone ring;
nm.cancel(getIntent().getExtras().getInt("notific
ationID"));
}
}
public void onPause() {
super.onPause();
pause_int = 1;
}
// Add the Actions to the Action Bar
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu items for use in the
action bar
MenuInflater inflater =
getMenuInflater();
inflater.inflate(R.menu.main_menu, menu);
return super.onCreateOptionsMenu(menu);
}
// Respond to Action Buttons
@Override
public boolean onOptionsItemSelected(MenuItem
item) {
// Handle presses on the action bar items
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
switch (item.getItemId()) {
case R.id.action_dis:
// start discovery
// create title bar menu
setContentView(R.layout.main);
ActionBar actiona = getActionBar();
ReadBluetoothAddress(); // read
targetted Bluetooth addresses
1
count_pre = RSSI_value;
time_elapse = 0;
CharSequence message = "You have lost " +
labels;
if (shec == 0) {
mTimer = new Timer(); //
create a timer to do regular discovering
TimerTask mTimerTask =
new TimerTask() {
@Override
public void
run() {
notif.setLatestEventInfo(context, from,
message, pendingIntent);
nm.notify(notificationID, notif);
}
startDiscovery();
}
Intent i
= new Intent(context, BluetoothActivity.class);
if
(count != count_pre) {
if (RSSI_value < sensitivity_value || time_elapse
== 30) {
time_elapse = 0;
ring.play(); // create a sound alarm
count_pre = count;
}
} else {
if (RSSI_value > sensitivity_value || time_elapse
time_elapse++;
< 30) {
}
if
((RSSI_value < -80 && time_elapse > 10) || time_elapse >
30) {
ring.stop(); // stop this alarm
}
}
Vibrator v = (Vibrator)
getSystemService(Context.VIBRATOR_SERVICE);
}
};
v.vibrate(100);// Vibrate for 100 milliseconds
if (dialog_int == 0) {
if (pause_int == 0) {
frag dialogFragment = frag
.newInstance("You have
lost Keys");
mTimer.schedule(mTimerTask, 1000, 1000);
shec = 1;
} else {
cease();
}
return true;
case R.id.action_edit:
startActivity(new
Intent("com.Beep Keep.Edit"));
return true;
dialogFragment.show(getFragmentManager(),
"dialog");
}
dialog_int = 1;
if (pause_int == 1) {
case R.id.action_gear:
startActivity(new
Intent("com.Beep Keep.Gearact"));
return true;
default:
return
super.onOptionsItemSelected(item);
}
}
// create a notification bar
int notificationID = 1;
i.putExtra("notificationID",
notificationID);
PendingIntent pendingIntent =
public class switchButtonListener extends
BroadcastReceiver {
@Override
public void onReceive(Context context,
Intent intent) {
cease();
}
PendingIntent
}
.getActivity(context, 0,
i, 0);
NotificationManager nm =
(NotificationManager)
getSystemService(NOTIFICATION_SERVICE);
Notification notif = new Notification(
R.drawable.logo32,
"You have lost "+labels,
System.currentTimeMillis());
CharSequence from = "Alert";
public void cease() {
shec = 0;
mTimer.cancel();
ring.stop();
time_elapse = 0;
dialog_int = 0;
}
private void initBluetooth() {
if (!bluetooth.isEnabled()) {
// Bluetooth isn't enabled,
prompt the user to turn it on.
Intent intent = new
Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(intent,
1);
}
1
}
tv1.setText(p2);
private void startDiscovery() {
IntentFilter intent = new IntentFilter();
intent.addAction(BluetoothDevice.ACTION_FOUND);
registerReceiver(searchDevices, intent);
bluetooth.startDiscovery();
}
BroadcastReceiver searchDevices = new
BroadcastReceiver() {
@Override
public void onReceive(Context context,
Intent intent) {
Bundle b = intent.getExtras();
Object[] lstName =
b.keySet().toArray();
short rssi =
intent.getShortExtra(BluetoothDevice.EXTRA_RSSI,
(short) 0);
for (int i = 0; i <
lstName.length; i++) {
String keyName =
lstName[i].toString();
Log.e(keyName,
String.valueOf(b.get(keyName)));
if
(String.valueOf(b.get(keyName)).equals(bluetooth_address)
) {
// if find the
device, get the RSSI value, and count increment by 1
RSSI_value =
rssi;
count++;
}
}
}
};
private void StartDiscover() {
mTimer = new Timer();
TimerTask mTimerTask = new TimerTask() {
@Override
public void run() {
runOnUiThread(new
Runnable() {
@Override
public void
run() {
TextView
tv1 = (TextView) findViewById(R.id.tx);
Switch
t1 = (Switch) findViewById(R.id.t_1);
String p
= ss[0];
String
p2 = "";
double
distance = (47.5 - RSSI_value) / 0.1202;
if (shec
== 1) {
p2 = " Last Update: " +
String.valueOf(time_elapse)
+ " seconds ago. ";
if (distance >= sensitivity_value) {
p += " (~" + distance + ")";
}
else if (time_elapse > 31) {
p += "( may be lost )";
}
}
t1.setText(p);
}
});
}
};
mTimer.schedule(mTimerTask, 1000, 1000);
}
private void Initial() {
RSSI_value = -100;
count = 0;
count_pre = 0;
time_elapse = 0;
// initialise the switches names
// will be able to add new switches by
users' setting
Switch t1 = (Switch)
findViewById(R.id.t_1);
Switch t2 = (Switch)
findViewById(R.id.t_2);
Switch t3 = (Switch)
findViewById(R.id.t_3);
Switch t4 = (Switch)
findViewById(R.id.t_4);
try {
// read the labels
FileInputStream fis =
openFileInput("labels.txt");
InputStreamReader isr = new
InputStreamReader(fis);
char[] i = new char[READ_BLOCK];
String s = "";
int c;
while ((c = isr.read(i)) > 0) {
String re =
String.copyValueOf(i, 0, c);
s += re;
i = new
char[READ_BLOCK];
}
ss = s.split("@@");
text1 = ss[0];
t1.setText(ss[0]);
t2.setText(ss[1]);
t3.setText(ss[2]);
t4.setText(ss[3]);
// read Bluetooth addresses
FileInputStream fis2 =
openFileInput("bluetooth_address.txt");
InputStreamReader isr2 = new
InputStreamReader(fis2);
s = "";
while ((c = isr2.read(i)) > 0) {
String re =
String.copyValueOf(i, 0, c);
s += re;
i = new
char[READ_BLOCK];
}
ss = s.split("@@");
bluetooth_address = ss[0]; //
for test only, read the first address
} catch (FileNotFoundException e) {
// TODO Auto-generated catch
block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch
block
e.printStackTrace();
}
}
private void ReadBluetoothAddress(){
FileInputStream fis2;
try {
fis2 = openFileInput("new.txt");
InputStreamReader isr2 = new
InputStreamReader(fis2);
2
String s = "";
int c = 0;
char[] i = new char[READ_BLOCK];
while ((c = isr2.read(i)) > 0) {
String re =
String.copyValueOf(i, 0, c);
s += re;
i = new
char[READ_BLOCK];
}
if
(s.equals("00:00:00:00:00:00")) {
bluetooth_address =
"00:21:08:66:2F:DF";
} else {
bluetooth_address = s;
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch
block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch
block
e.printStackTrace();
}
}
// ---- change the switches background colors
<end> --}
// ---- change the switches background colors
<start> --public void SwitchClick_blue(View view) {
Switch toggle = (Switch) view;
if (toggle.isChecked()) {
toggle.setBackground(getResources().getDrawable(R
.drawable.b_b2));
} else {
toggle.setBackground(getResources().getDrawable(R
.drawable.b_grey));
}
}
public void SwitchClick_purple(View view) {
Switch toggle = (Switch) view;
if (toggle.isChecked()) {
toggle.setBackground(getResources().getDrawable(R
.drawable.b_g2));
} else {
toggle.setBackground(getResources().getDrawable(R
.drawable.b_grey));
}
}
public void SwitchClick_red(View view) {
Switch toggle = (Switch) view;
if (toggle.isChecked()) {
toggle.setBackground(getResources().getDrawable(R
.drawable.b_r2));
} else {
toggle.setBackground(getResources().getDrawable(R
.drawable.b_grey));
}
}
public void SwitchClick_yellow(View view) {
Switch toggle = (Switch) view;
if (toggle.isChecked()) {
toggle.setBackground(getResources().getDrawable(R
.drawable.b_y2));
} else {
toggle.setBackground(getResources().getDrawable(R
.drawable.b_grey));
}
}
3
belongings when they are on the go. This concept is
illustrated in Fig. 1.
Appendix C. Project Proposal
Abstract----- It is essential for us to bring our IDs,
phones, travel cards, wallets, keys etc. along when we
go out. However, people nowadays are clumsy to
leave their belongings when they are too hectic on
work and social lives. Due to increasingly heavy
reliance on social media, phones are the least
forgotten.
ADDITIONAL INFORMATION
Research
Intensive researches and studies are needed to miniature and
optimise this system, in order to make it less nettlesome and
conspicuous. Bluetooth 4.0 is the latest version and has the
primary feature of power efficiency [3]. The new single-mode
chips are promoted to be at an even lower cost. In terms of
their effectiveness, new protocol supports as far as 150 metres
[4]. In order to maximize power supply, the use of button cell
which would last for a few years or even longer is currently
under development. The implant of Bluetooth smart chip is
preferred due to its low energy consumptions [5]. It can be
powered wirelessly with recommended security.
Beep-to-Go is a reminder application built in the
smartphone which links to smart stickers labeled
onto these items. It works based on Bluetooth
technology. It is suitable for everyone especially the
elderlies and the disables. Whenever they go out,
Beep-to-Go ensures that they bring all the necessary
items along.
Expertise
This proposal requires knowledge on Signal
Processing for the Bluetooth, Analog Electronics for the
circuits implanted onto the stickers and Programming
skills for the mobile applications (detect distances,
register stickers on items etc.). We planned to program
the apps so that they can be applicable on all smart
phone platforms.
FEASIBILITY STUDY
The mobile app links to belongings with stickers
implanted with Bluetooth smart chips [1]. Whenever the
users need to bring their belongings, they can put
stickers on the belongings to remind themselves via a
check list app on their phone. The app works by
switching on the Bluetooth mode on the phone. The
users have to register the labeled items with stickers on
the phone for ease of reminding themselves. Even if the
users forget about the check list, as long as the distances
between the users and their items exceed a certain
amount, the smart phone will alarm the users. If he/she
checks the list before leaving, he/she can tap the listed
items to make sure those items are with them.
Costs
The app is free of charge and can be downloaded onto
all smart phones. However, research and manufacturing
funds are required for the stickers with implanted
Bluetooth chips. Stickers are meant to be flexible,
portable and durable. We estimate that this will take us a
few months to complete a demonstrator provided that we
have sufficient knowledge on the production of quality
stickers and financial support. For additional features, we
will consider to put a buzzer on these stickers too so that
the users are able to find them easily by searching the
sound source. The project is estimated to cost less than
40 pounds.
FEATURES
Fig.1 Blue print of Beep-to-go
Though there are a variety of check list applications
available
in the
market,
none of
them have
the ability
to produce
audio
signal as
an alarm
for the
user via
smart
phone
when the distance between the user and the items exceed
a predetermined distance. Inspired by OPPO’s O-Click
[2], we desired to design this to prevent people from
leaving their important belongings behind. It is also
designed to prevent the user from losing important
References
[1] Nick Flaherty, “Implantable 'lab on a chip' monitors
health via Bluetooth,” EE Times Europe on 21st
March 2013. Available:
http://www.electronics-eetimes.com/en/bluetoothsig-and-a4wp-to-shape-wireless-chargingstandard.html?cmp_id=7&news_id=222918531&vI
D=44
[2]
Available: http://en.oppo.com/products/n1/ By
OPPO
[3]
http://chapters.comsoc.org/vancouver/BTLER3.
pdf
[4] Adopted Bluetooth® Core Specifications Core
Version 4.0: https://www.bluetooth.org/enus/specification/adopted-specifications
[5] Security, Bluetooth Smart (Low Energy) from
Bluetooth Developer Portal.
Available:
https://developer.bluetooth.org/TechnologyOvervie
w/Pages/LE-Security.aspx
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Appendix D. Datasheet of CR2032
Ref: Product Datasheet Energizer CR2032
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References: The Swiss Power Source Renata Batteries Datasheet for CR927
Appendix E. General Engineering specification of Bluetooth 4.0
Range
Output Power
Max Current
Latency
Topology
Connections
Modulation
Robustness
Security
Sleep current
Modes
Bluetooth low energy factsheet
~ 150 meters open field
~ 10mW (10dBm)
~ 15mA
3 ms
Star
> 2 billion
GFSK @ 2.4 GHz
Adaptive Frequency Hopping, 24 bit CRC
128bit AES CCM
~1µA
Broadcast, Connection, Event Data Models, Reads, Writes
Note: items marked in blue are defined in the specification; other items are implementation
specific.
Reference circuitry
3
Schematic for nRF8001 with DC/DC converter enabled
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References: Introducing Bluetooth Smart By Joseph Decuir Part 1: A look at both classic and new
technologies.
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Appendix F. Comparison between Classic Bluetooth & Smart Bluetooth
Technical Specification
Classic Bluetooth technology
Bluetooth Low Energy Technology
Distance/Range
100 m (330 ft)
50 m (160 ft)
Over the air data rate
1–3 Mbit/s
1 Mbit/s
Application throughput
0.7–2.1 Mbit/s
0.27 Mbit/s
Active slaves
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Not defined; implementation
dependent
Security
56/128-bit and application
layer user defined
128-bit AES with Counter
Mode CBC-MAC and application
layer user defined
Robustness
Adaptive fast frequency
hopping,FEC, fast ACK
Adaptive frequency hopping, Lazy
Acknowledgement, 24-bit CRC, 32bit Message Integrity Check
Latency (from a nonconnected state)
Typically 100 ms
6 ms
Total time to send data
(det.battery life)
100 ms
3 ms, < 3 ms
Voice capable
Yes
No
Network topology
Scatternet
Star-bus
Power consumption
1 as the reference
0.01 to 0.5 (depending on use case)
Peak current
consumption
<30 mA
<15 mA
Service discovery
Yes
Yes
Profile concept
Yes
Yes
Primary use cases
Mobile phones, gaming,
headsets, stereo audio
streaming, automotive, PCs,
security, proximity, healthcare,
sports & fitness, etc.
Mobile phones, gaming, PCs,
watches, sports and fitness,
healthcare, security & proximity,
automotive, home electronics,
automation, Industrial, etc.
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Appendix G. General specifications of Cellergy’s supercapacitor
Parameter
Rating
Capacitance tolerance
-20% /80%
Capacitance range
7mF to 700mF
18mΩ to 1200mΩ
ESR range
Working voltage
Power
Foot print
Operating temperature
0.7-18.0 volts
10's of Watts, short pulse widths
12 × 12.5 mm, 10 × 15 mm, 17 × 17.5 mm, 28× 17.5
mm, 48 × 30.5 mm
-40°C to +70°C (CLC series)
Storage temperature
-10°C to +35°C
Surge voltage
15% above rated voltage
Pulse current
No limit
De-rating
Not required
Polarity
No polarity
Number of full charge/discharge cycles
Safety
Over 500,000
Constructed from environmentally friendly materials,
toxic fumes are released upon burning
[Cellergy pg 14 Diagram of through hole double lead]
References:
1. General Engineering Specification for Cellergy’s Super Capacitor
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