CPE 322 – HW7
Personal Navigation System Glasses
Siti Srinorlela Rosdi
Ilham Mohd Azmi
Siti Nadhirah Mohamad Rahim
Nazhatul Kamarudin
Sulastrie Sukri
We pledge our honors that we have abided by the Stevens Honor System
Contents:
Introduction………………………………………………………………………………………………………………3
Hardware Block Diagram……………………………………………………………………………………………4
Software Block Diagram…………………………………………………………………………………………….8
Design Constraints…………………………………………………………………………………………………….10
SWOT analysis…………………………………………………………………………………………………………..12
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Introduction
In this report, the group provides two flowcharts which are the hardware and software flowcharts. The
group also includes the design restriction and SWOT analysis. The work division for this report is as
stated in the table below.
Member
Task
Ilham Mohd Azmi
Software design
Nazhatul Kamarudin
Design restriction and SWOT analysis
Siti Nadhirah Mohamad Rahim
Hardware design
Siti Srinorlela Rosdi
Software design
Sulastrie Sukri
Hardware design
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Hardware Block Diagram
The physical components for the project to be produced are switches, microphones, speakers, LEDs and
GPS receiver. The most important component that provides electricity to the whole circuitry inside GPS
glasses is the lithium ion battery. With all the components needed, the project can do its purpose.
Switches
There will be two switches implanted right on the glasses frame. One for on/off button and
another one is for reset button. The on/off button is to generate the flow of electricity, in other word is
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to start the system. The reset button is mainly used to reset the system. Below is an example of push
button switch that is available to be used for the design. The button should be light such that it will not
bring inconveniences to the user.
< http://www.sparkfun.com/products/97>
Speaker
The second component is speaker. The group will be using two speakers which each one of
them will be implanted both sides of the glasses frame. The speakers will produce sound from the
electrical audio signal that they received. The speaker dimension is 30mm x 10mm which is suitable to
be built into the glasses frame.
< http://szhonson.en.alibaba.com/productshowimg/431760753-212205266/30X10mm Rectangle
Computer _speaker.html>
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Microphone
The third component is microphone. The microphone is also to be built into the glasses frame.
The microphone is for the user to give the information about the desired destination and then the
microphone will convert the sound wave into an electric signal. The problem of surrounding noises will
be overcome by using the noise cancellation technology as discussed in Homework 4. There are two
designs that the group is considering about: 1) with a microphone and 2) with two microphones. The
second design will use more electricity and the available lithium ion battery has limited capability.
Battery
The forth component is the two Lithium ion Batteries. This product specifically uses one CR2032
battery as the source of energy. It provides 3 volts of power per battery to operate product. The group
decides to use this type of battery because of its small size. This is a very important criterion to make
sure that it can fit into the small component that is places at one side of the frames. The dimension of
this battery is 4 in x 2 in x 1 in. This lithium battery is very cheap which costs only about $0.50. Therefore,
the users will not have a problem to replace it.
< http://www.overstock.com/Electronics/Lithium-Coin-Battery-CR2032-Pack-of5/3521764/product.html >
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LED
The fifth components are LED lights. This product uses two different colors of LED light which
are red and green. The colors of the LED lights will tell the user whether they are in the right direction or
not. When the red LED is light up, it indicates that the user is in wrong direction and the other way
around.
<http://www.crunchgear.com/2010/08/03/video-this-pair-of-glasses-is-actually-a-personal-navigationsystem/>
GPS receiver
The last and the most important component is the GPS receiver. Basically, GPS satellites
broadcast the time and data about their location. Then, the GPS receiver will receive a few signals from
different satellites and compare them. The GPS receiver will calculate its distance from the satellites and
use triangulation to figure out its own location.
<http://www.how-gps-works.com/>
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Software Block Diagram
As the device is activated by a switch, an input signal will be given by the user through the
speech recognition process to initially set the destination. The speech recognition fundamentally
functions as a pipeline that converts PCM (Pulse Code Modulation) digital audio from a sound card into
recognized speech. The elements of the pipeline include transformation of the PCM digital audio into a
better acoustic representation, identification of phonemes spoken, reducing the computation and
increasing accuracy. Significant tolerance against variations in the acoustic signal related to this would
be voice level variability, the ability to cope with microphones with different frequency response and
with changing environmental conditions. Since the device works based on the voice commands, the
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whole process will go through quite a number of interactions between the user and the verbally
responding interfaces.
Given that the instructions are simultaneously being recognized, the input would be configured
by the GPS to work on the positioning calculation. The GPS calculation in the receiver uses four
equations in the four unknowns x, y, z, tc, where x, y, z are the receiver’s coordinates, and tc is the time
correction for the GPS receiver’s clock. Depending on the accuracy of the clock in the GPS receiver, the
determined position will be more or less wrong. For the practice of GPS based navigation this would
mean that no determined position can ever be of any use, as the runtimes of the signals are so short,
that any clock error has an overwhelming influence on the result. By constantly recalculating its position,
the GPS receiver can additionally determine the speed and direction of a movement (referred to as
"ground speed" and "ground track").
Corresponding to the GPS directional procedure are the LEDs which are going to flash on showing
whether or not the user is heading to the correct route. It somehow keeps up a correspondence just to
certain range of movement since the user might not want undesired recalculation every time he moves
his head.
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Design Constraints
Economic:
For the GPS device price, we can see that the basic price for the device is about S150 but it is do
not have some of the important features that we need like higher-quality speaker, travel conveniences,
navigation without signal, and also voice address input. For a better GPS navigation device, we have to
spend about $300, which is quite high. But, the price for build in microphone and speaker is not too
costly. Therefore, we have no problem in term of financial constraint for the build in speaker and the
microphone.
For the basic noise reducer, we can get for only $20++. But, in order to overcome some
problems from the noise reducer, we plan to use noise cancellation technology in this device which will
need more money to buy an advanced noise-reducer. Basically, we can reduce the economic constraints
by using a simple noise-reducer and install some new software in that device to overcome some
background effect. The most important thing to be considered to create this personal navigation glasses
is the type of material that we want to use. We decided to use CR-39 plastic lenses which is quite
reasonable in term of price thus we can reduce our economic constraint.
Environmental:
Drivers use GPS application to ease their journey. The folded paper maps are replaced with this
advance technology, which is this personal navigation glasses. With this product, we can reduce the
usage of paper. Material being used in manufacturing the glasses built-in GPS system is mostly the same
as in normal glasses. In conclusion, the group’s project will not affect the environment.
Manufacturing constraint:
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To build this personal navigation glasses, we need to input a GPS chip into the frame, and we
also need to put build in microphone and speaker. It will be kind of hard to put these electrical
components into this personal navigation glasses. It might need extra research and lots of design work.
These include power supply for the circuitries and signal multipath. Other than that, the group has to
think of having a power supply that is sufficient for the components without putting too much additional
weight to the glasses. Batteries might just work but it should be in the perfect size and weight with the
best capacity of electricity. For manufacturing these personal navigation glasses, we will need a lot of
patience and concentration since every components involved will be tiny and vulnerable to damage. Not
only that those are expensive but also easy to lose, hence the group has to make sure the circuitries are
well managed and the storage is organized.
Health and safety:
Many people are curious about the health effect of the use of GPS. It is due to the radiation
emitted by the device. The users are curious of the effects of the radiation to the brains. As there are
lacks of formal studies to prove microwave radiation to be unsafe, the radiation is claimed to be safe. It
has also been approved by the FDA to be used by consumers. Then, as the GPS is located at the frame of
the glasses, the group has to ensure the insulation and heat flow are done properly. It is to reduce the
temperature increase that might lead to hot ear and face and also explosion.
Satellite communication errors and outdated or inaccurate maps can cause accidents for visual
impaired users. It is because they are not able to confirm the information given by the GPS. These errors
can also affect the normal users as they take GPS device's instructions too literally.
Sustainability constraints
The team decided to use CR-39 plastic lenses for the prescription glasses because of they are
lightweight, less likely to shatter and have better protection against ultraviolet (UV) light criteria.
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Nevertheless, the CR-39 plastic lenses are more prone to scratch compared to glass lenses. However,
this problem can be solved by adding scratch-resistant coating to the lenses. Even thought the CR-39
plastic lenses are less likely to shatter, they are not totally impact proof. Therefore, the users have to
avoid from wearing the glasses to play a sport. The frame of the Personal Navigation System glasses are
made of nylon which is strong and lightweight compared to other types of plastics. Even though nylon is
strong, it is still breakable. The strength of the nylon frame will slightly decrease after being exposed to
sunlight for a long time. Besides, the color of the frame can fade over time.
SWOT analysis
Strengths1. This device is a new product in a new market. It is because there are no other products that
combine GPS and a pair of glasses.
2. Voice activated device is an emerging technology today. Thus the group believes that this
product will be able to grab the attention of the targeted customers.
3. This product can also be used by vision impaired people as it is activated by voice. So they do
not have to type in the address of the desired location.
Weaknesses –
1. For this personal navigation glasses, there could be a problem for us to put the chip in the frame
of the glasses.
2. The navigation glasses has to made lighter as we would need to install a GPS chip and we need
to put a speaker in the frame. The battery and electrical components in the frame also might
add weight to the glasses. Therefore, the users might feel uncomfortable wearing it.
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3. All the components in this personal navigation glasses are built-in components. Thus, it requires
high cost that will lead to high price. It might a little bit expensive compared to any other glasses.
4. The batteries used will not be last long but the price of the batteries is kind of cheap, therefore
we can easily replace the batteries.
Opportunities –
1. This personal navigation glasses is a new product in the market. Therefore, it might become the
most wanted device of the year as there is no other product that has these kind of features yet.
2. This product might be one of the trendiest glasses as its features will attract a lot of young
people.
3. Improvement can be made to this personal navigation glasses by using light and compact
materials in order to make it less heavy.
Threats1. The electrical device that is located near to the brain arise the question of safety and health.
2. Inaccurate map and error in satellite communication might lead to accidents as users totally rely
on the GPS instruction
3. The heat released by the electrical components might result in hassle to the users.
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