Purdue ECE Senior Design Semester Report
Course Number and Title
Semester / Year
Advisors
Team Number
Project Title
Name
Kathleen Klacik
Brian Baumgartner
Dan Strauss
Kyle Anderson
ECE 477 Digital Systems Senior Design Project
Fall 2008
Profs. Meyer and Johnson
1
SHU: The Running Companion
Senior Design Students – Team Composition
Area(s) of Expertise
Major
Utilized in Project
EE
Hardware
EE
Harware
CompE
Software
CompE
Software
Expected
Graduation Date
May 2009
May 2009
May 2009
December 2008
Project Description: Provide a brief (two or more page) technical description of the design
project, as outlined below:
(a) Summary of the project, including customer, purpose, specifications, and a summary of the
approach.
SHU: The running companion is targeted at both casual and serious runners. It is meant to
assist all runners in his or her training by providing them with the real time knowledge that
he or she needs. It displays up to date running statistics on the LCD screen and offers a
variety of training modes. It is meant to be worn on the runner’s upper arm and can be
attached with an arm strap. SHU’s lithium ion battery can be charged through a connection
to an external wallwart.
In our project we used a freescale MC9S12XDT256 microcontroller interfaced with several
components to achieve the desired functionality. The external components used were and
SD reader/writer board, a GPS receiver, a speaker, a fuel gauge IC, and an LCD screen
with push buttons. In order to interface with these components and achieve desired
functionality we used the following on chip peripherals: SCI, PWM, and TIM. SCI was used
to communicate with the GPS, SD card reader/writer, and the LCD screen. PWM was used
to drive the speaker and TIM was used in order to maintain an accurate stopwatch. A
battery charging IC (MAX8776) was used in order to switch between a battery power supply
and a wall wart supply as well as to charge the battery.
(b) Description of how the project built upon the knowledge and skills acquired in earlier ECE
coursework.
We found that our project built upon almost all previous ECE coursework, but relied most
heavily upon the knowledge gained in 362 and 270. These classes equipped us with the
knowledge of how to approach embedded systems and familiarized us with microcontrollers
and how to program them. It should be noted that 201 and 202 as well as 255 were
employed at some points in our project design when deciding what our passive components
would be. We also built upon the skills learned in 264, C programming when doing all of
our programming on our microcontroller.
(c) Description of what new technical knowledge and skills, if any, were acquired in doing the
project.
Firstly, this was the first time anyone had done a PCB layout. The software used to create
the layout and the conventions used in placing parts and routing traces required much
learning—often times through trial and error.
Also, this was the first time anyone on the team had worked on a project of this scale. The
planning involved with determining what parts were needed and actually ordering those
parts proved more difficult than expected. By the time the last parts were ordered, the
methods and organization used to do so had become much smoother and more honed.
Thirdly, the software development process was something that was also relatively new. In
previous projects, the process of programming the microcontroller and flashing the
controller’s memory was something that those working on it were mostly walked through.
This time around, the development environment, the low-level specifics of programming,
the method of flashing and debugging the controller, and the process of debugging the
program for each individual external component were all more complicated and less laid our
for the developers than previously had been.
(d) Description of how the engineering design process was incorporated into the project.
Reference must be made to the following fundamental steps of the design process:
establishment of objectives and criteria, analysis, synthesis, construction, testing, and
evaluation.
In our design project, the first step is to decide upon project specific success criteria. These
are the objectives that we would like our project to accomplish. After deciding on success
criteria, the next step is to pick out the parts that our project will need in order to accomplish
our set goals. To do this we needed to analyze the things that we want our project to do
and then decide on the specific IC or hardware configuration to do this. It is important that
we paid attention to the specific things that we wished for our hardware to do and also that
we paid attention to the ratings of every IC and discrete components that was chosen. If
we had neglected to pay attention to the ratings of the ICs and discrete components, there
is a good chance or project would not have worked, because of this the step of analyzing
was very important to our project. Checking to make sure all of our parts would work
together by paying attention to their ratings is also part of the synthesis step in the design
process. Without doing this, there would be no guarantee that our chosen parts would work
together to form our final project. In addition, it is important to have a solid schematic going
into the PCB design, where we really began to visualize what our project will look like when
it is all finished. During the construction phase, we ran into a couple problems with our
PCB. Our main problem was that we neglected to make a connection for a ground plate on
one of our ICs. After we came up with a solution to this problem, we managed to assemble
the rest of our PCB with minimal incidents.
(e) Summary of how realistic design constraints were incorporated into the project
(consideration of most of the following is required: economic, environmental, ethical,
health & safety, social, political, sustainability, and manufacturability constraints).
Economic: Economically, our design was constrained in the sense that we limited the
amount of unnecessary features our device would have. In the beginning we were looking
at making our device a touch screen device but decided against it because of both cost and
complexity purposes.
Environmental: Our product does not have much of an impact on the environment other
than in the LCD manufacturing phase and in the recycling phase. In order to combat these
problems, we could use green LCDs and offer a monetary reward system so that the user
would send their product back to us and we could recycle the parts when the original
product’s life cycle is over.
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Ethical: Our project’s main ethical concern is whether we will test our project well enough
to go to market and also whether our battery could potentially short and cause a fire or
extreme heat and burn the user’s arm. In order to combat these issues, we will put our
project through thorough tests such as lots of shaking, some extreme motion jolts, and
moisture testing. In the case of the battery, we could just put a fuse in line with it to prevent
a short circuit between ground and power.
Health & Safety: Certain failure modes posed a safety risk to the user. If any voltages went
too high, there was the potential for high temperatures which could cause burns to the user.
The battery, especially, could become dangerous if anything went seriously wrong. Safety
checks, both in software and hardware needed to be added. In the initial design process,
portability took precedence over safety. Nonetheless, fuses and emergency shutdown
modes were added.
Sustainability: It was necessary that our device be able to sustain a lifetime of wear and
tear on the user’s arm. Due to this it was necessary that our product be thoroughly tested
to ensure that it would not fail prematurely during routine usage. We needed to make sure
that we used very durable materials and employed durable foam to keep parts from moving
around inside the enclosure.
Manufacturability: When picking out parts, we used parts that were mostly easy to
integrate. It was necessary that our product was designed in such a way that it would be
easily manufactured and would also be profitable.
(f)
Description of the multidisciplinary nature of the project.
Many different disciplines of skills needed to be used for this project. There was the obvious
division between electrical and computer engineering. Schematic design was more
electrical engineering, while programming the processor was more computer engineering.
The two came together for the PCB layout design and circuit board population.
There was also the more managerial work such as putting together presentations, ordering
parts, and writing the final report.
Some reports touched on patent law, safety and ethics, and marketing.
(g) Description of project deliverables and their final status.
SHU currently meets three out of five project specific success criteria. The user is able to
successfully navigate the menu system using pushbuttons and the LCD. The battery is
able to be charged through a connection to an AC wallwart, and the fuel gauge displays the
amount of battery left on the screen. We hope to get the SD card storage and GPS
tracking ability working soon.
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