University of Portland
School of Engineering
5000 N. Willamette Blvd.
Portland, OR 97203-5798
Requirements and Functional
Specifications
Frequency Response Audio Visualizer
Team Members:
Jake Nylund (Fall Team Lead)
Kevin Ratuiste (Spring Team Lead)
Alex Arlint (Treasurer)
Robert Rodriguez (Secretary)
Industry Representatives:
John Turner – Impinj, Inc.
Faculty Advisors:
Dr. Joseph Hoffbeck
Clients:
Will Taylor – Student
Phone 503 943 7314
Fax 503 943 7316
FUNCTIONAL SPECIFICATIONS
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REVISION HISTORY
Rev.
Date
Author
0.9
20 Sept 2013
Team
Final edits made before submitting to Dr. Hoffbeck
0.95
26 Sept 2013
Team
First revisions after reviewed by Dr. Hoffbeck
1.0
3 Oct 2013
Team
Update and added detail
UNIVERSITY OF PORTLAND
Reason For Changes
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TABLE OF CONTENTS
REVISION HISTORY ................................................................................................................ 2
TABLE OF CONTENTS ............................................................................................................. 3
INTRODUCTION ..................................................................................................................... 4
REQUIREMENTS .................................................................................................................... 5
USE CASE ............................................................................................................................... 7
USER INTERFACE.................................................................................................................... 8
DEVELOPMENT PROCESS ....................................................................................................... 8
MILESTONES........................................................................................................................ 11
PRELIMINARY BUDGET ........................................................................................................ 12
FACILITIES ........................................................................................................................... 12
RISKS ................................................................................................................................... 13
CONSTRAINTS ..................................................................................................................... 13
CONCLUSION ....................................................................................................................... 14
GLOSSARY ........................................................................................................................... 15
REFERENCES ........................................................................................................................ 15
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INTRODUCTION
The project, Frequency Beats, by team Couch Street, will be a sound visualizer utilizing the
reaction of ferrofluid to magnetic fields. A visualizer is an animated representation of sound
waves. Some electronic music players come with this feature built in, generally in the form of
LEDs. Figure 1 is a basic representation of a digital visualizer. Ferrofluid is a fluid containing tiny
magnetic particles, typically iron, which react to magnetic fields. Figure 2 shows one example of
ferromagnetic fluid using a simple magnet.
Figure 1: LED Visualizer
Figure 2: Ferromagnetic Fluid
The genesis of this project arose from two distinct proposals generated and promoted by
different team members. One member’s desire was to work with ferromagnetic fluid to better
understand its unique properties and to gain proficiency with its use. Another team member
proposed working with sound to process audio input. Initially these competing ideas seemed
unrelated. However, through further team discussion, the idea of using ferromagnetic fluid to
represent audio input arose and seemed like the perfect combination of both project ideas.
Certainly visualizers are not a new technology. The first electronic music visualizer was the Atari
Video Music system introduced by Atari Inc. in 1976. It was designed by Robert Brown, the
initiator of the home version of Pong, the first video game to reach mainstream popularity. Our
goal is to take something old and put a new spin on it. To our knowledge, there is not a
commercially-available ferromagnetic fluid visualizer, though there is another college design
project very similar to the concept this team has decided on. A video on YouTube of their final
project is available at http://www.youtube.com/watch?v=6hLeKBNHBk4.
Our final result should resemble the concept sketch provided in Figure 3 below.
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Figure 3: Front, Top, and Rear View Concept Sketch
REQUIREMENTS
The overall goal of this device is to visualize the frequency response of an audio signal. A
microcontroller will filter Low, Mid, and High frequencies and send the appropriate current to
the respective electromagnet based on frequency amplitude to actuate the ferrofluid according
to the audio’s frequency response. The actuation will be in the form of the ferrofluid in the
containers rising when the audio contains strong frequency signal in the respective frequency
range.
Overview
The input will be an analog line level audio signal connected via a standard 3.5mm headphone
jack. This signal will enter the microcontroller, such as an Arduino, where it will be processed
and filtered to separate the various frequencies in the audio signal. Implementing the filters
digitally allows more flexibility in how the microprocessor will process the signal as well as the
resulting action or response. Once the frequencies of the audio signal are separated, they will
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be output to the electromagnets, which, in turn, will manipulate the ferromagnetic fluid
creating a visual representation of the audio signal.
Figure 4: Functional Block Diagram
Client Specifications
Audio Accompaniment:
The client would like speakers included with the product, so that the audio signal can be
heard in conjunction with the ferromagnetic fluid display.
Buttons:
To allow for easy testing, debugging, and demonstration, the user can press three
buttons, respectively, to allow activation of the electromagnets without music.
LEDs:
To assist in the aesthetic appearance of the display, the client would like to see LEDs
pulse with the music as well. This will complement the movement of the ferromagnetic
fluid.
Ferromagnetic Fluid Response:
The ferromagnetic fluid should respond instantaneously to the music with no noticeable
lag. This will be particularly important since the audio signal will be heard
simultaneously through the speakers.
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Physical Specifications
Form Factor:
The project will consist of four major components: cubic display cases, electromagnets,
a microcontroller, and a power supply. These components will be mounted on a flat
piece of wood with a divider between the functional hardware and the display cases.
The finished product will be small enough to fit into the display case in Shiley and is
expected to be no taller than one foot; it should be easily transported by two people.
Use:
The product is meant as a display piece and should be operated indoors at room
temperature (approximately 72 °F) and on a level surface. When in use, it should not be
moved around. While it will be sturdy enough for typical transportation, it is not
designed to survive drops and impacts. Exposure to direct sunlight should be minimized
to avoid evaporation of the fluid housing the ferromagnetic fluid.
Hardware Specifications
General:
The hardware the team will be utilizing will be a microcontroller (i.e. Arduino). The only
software necessary for the product will be an open source microcontroller environment
(i.e. Arduino programming environment) and/or MATLAB to program the
microcontroller. The software does not restrict us to using a specific computer operating
system.
Power:
The device will likely require a large amount of current. With this in mind, the team is
planning on using one of the Engineering Lab power supplies Through testing the
behavior and characteristics of ferromagnetic fluid, it will be possible to determine the
amount of current needed to create the desired response of the fluid.
USE CASE
Planned Use Cases:
A user displays frequency visualization for a performance or personal recreation.
Primary Actors:
User, Electromagnets (3), Ferromagnetic Fluid, Arduino Board, Audio Input
Goal in context:
Display the simple frequency response (Low, Mid, High) in the ferromagnetic fluid
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Preconditions:
The device is powered.
Trigger:
The user inputs an audio signal. The microcontroller processes the signal.
Scenarios:
1. The user inputs the audio signal to the microcontroller.
2. The microcontroller processes the audio signal, filtering the frequency response of the
audio.
3. The microcontroller forwards the appropriate current to each electromagnet corresponding
to the respective frequency amplitude.
4. The electromagnet gives off an electromagnetic field with the appropriate intensity, causing
the surrounding ferromagnetic fluid to react to the respective magnetic field.
Exceptions:
1. The user selects an audio file with amplitudes above the current capacity
microcontroller board and/or electromagnets, in which case the microcontroller will
scale to the maximum safe current.
2. The input audio is silence, in which case the electromagnets do not receive current
and the device does nothing.
Open issues:
1. Calculating the current required for each of the electromagnets.
2. Finding a power supply that will meet the requirements for the magnets.
3. Finding the optimal positions for the electromagnet in relation to the ferromagnetic
fluid to create the best response.
4. The best way to process the input signal and filter accordingly.
USER INTERFACE
The user will plug in their audio signal via a 3.5mm standard audio cable on the back side of the
project device. Once connected, the user presses play and watches the audio visualization of his
or her music choice on the front side of the device. Alternatively, the user may press one of the
three buttons present on the front of the device to actuate the ferromagnetic fluid without
audio.
DEVELOPMENT PROCESS
Below is a diagram and description of the development process laid out for the design and
production of the ferromagnetic fluid visualizer.
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Ferromagnetic Fluid /Electromagnet Tests
The initial tests of the fluid will be key to the success of this project. During these tests, the
team members will determine the best way to manipulate ferromagnetic fluid, and what is a
reasonable response to expect from the magnets and ferrofluid. In particular, the goal is to
understand how quickly ferromagnetic fluid can move and how much current it takes to
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produce the desired result. In addition, the difference between using ferrofluid in and out of
water will be tested.
Determine Ferromagnetic Fluid Display Design
Taking the results from the Ferromagnetic Fluid /Electromagnet Tests, the team will design the
individual ferromagnetic fluid displays. During this step, the dimensions and material of the
display case will be decided.
Determine/Design Filters and Electromagnet Controllers
The filters will be implemented digitally through custom coding of a microcontroller. It will be
determined how exactly what parameters are needed to create the desired filters. The
electromagnetic controllers will be told by the microcontroller when to turn the magnets on
and off as well as supplying the proper current.
Design Document
After performing the experiments with the electromagnets, it will be possible to create the
Design Document which will specify, in detail, our calculations, specific parts, and circuit layout.
Build Base
The base of the product will be built. It will likely be made of plywood.
Build One Ferromagnetic Fluid Display
Get one fully functional Ferromagnetic Fluid display built before building the others. This will
allow for a much easier debug process and less time and money spent overall.
Program Microcontroller (One Display)
The microcontroller will be programmed to operate one ferromagnetic fluid display.
Test/Debug Display #1
A significant milestone will be this first test/debug effort. Using the microcontroller and the
assembled ferromagnetic fluid display, the team will test the visualizer to see if it is producing
the desired response. It should be possible to see the ferromagnetic fluid respond from at least
a few feet away. If it meets the standards, construction of the next displays will begin.
Build Remaining Ferromagnetic Fluid Displays
Construction of the remaining two displays will be completed.
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Program Microcontroller (Multiple Displays)
Add the additional functionality to the microcontroller code that will allow it to control multiple
Ferromagnetic Fluid displays.
Final Assembly
At this point, the entire project, displays, controllers, and so on, will be built into one unit. The
multiple ferromagnetic fluid displays and the microcontroller will be mounted to the base.
Test/Debug Display #2
This is the final set of tests. The entire device will be tested to ensure that it operates as
desired.
Founder’s Day Presentation
The completed project will be presented on Founder’s Day.
Final Report
The final report will be submitted. This document will include the project’s final design,
schematics, and budget.
MILESTONES
Note: A single asterisk (*) denotes a major milestone in the project. Two asterisks (**) denotes a particularly critical aspect
of the project.
First Draft of Functional Specifications Document:
9/20/2013
Adviser Approved Draft of Functional Specifications Document:
9/27/2013
* Final Draft of Functional Specifications Document:
10/4/2013
* Complete Testing of Ferromagnetic Fluid & Electromagnets:
10/13/2013
Determine Filters for Signal Processing:
10/20/2013
Determine which Microcontroller to use and test:
10/20/2013
* Finalize Design Layout and Specifications:
10/27/2013
First Draft of Design Document:
11/1/2013
Adviser Approved Draft of Design Document:
11/8/2013
* Final Draft of Design Document and Final Budget:
11/15/2013
Order All Parts:
12/1/2013
Finish Building Base and Get Audio Input:
1/17/2014
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** Finish Building One Ferromagnetic Fluid Display:
1/24/2014
** Finish the Digital Signal Processor Controls:
1/31/2014
**Construct and Test the Processor Control Circuit
2/3/2014
* Testing and Debugging / One Fully Operational Display:
2/7/2014
Build Second and Third Displays:
2/21/2014
Add Signal Processing for Two More Filters:
2/28/2014
* Final Assembly Testing:
3/14/2014
First Draft of Final Report:
3/21/2014
Adviser Approved Draft of Final Report:
3/28/2014
* Final Draft of Final Report:
4/4/2014
* Founder Day Presentation:
4/8/2014
PRELIMINARY BUDGET
Based on the design concepts, prices from multiple sources have been compared and an initial
estimate of $270 has been calculated. Below is a layout of how the university allotted funding
for this project will be spent.
Table 1: Preliminary Budget
Quantity
3
6
2
1
1
1
1
1
Material
½” x 3” steel pipe nipple
Steel electrical conduit covers
Magnet wire 16AWG spool (500’ each)
120V wall power supply
Arduino UNO
Plexiglas sheet to make display cubes
Magnetic ink (160g)
3.5mm female adapter
MISC parts
TOTAL
Cost
$10
$20
$40
< $50
$25
$75
$20
$5
$25
$270
FACILITIES
Throughout the experimentation, design, and construction process of our project will make use
of the bench space and equipment in Shiley 306. As far as software requirements, there are
open source microcontroller environments and/or MATLAB on any Engineering build computer.
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The equipment used will likely be limited to a soldering iron, ICs, and various hand tools for
construction.
RISKS
Below is a comprehensive list of the anticipated risks the project could face as well as some
contingency plans:
Risk: It could be difficult to find a power supply that produces enough current and then to
design the controller circuit to control that current.
Contingency: It would be possible to use smaller, separate power supplies that would each be
easier to control and locate.
Risk: The Ferro fluid reacts differently in water than expected.
Contingency: There are alternative liquids that can be mixed with the ferrofluid It instead of
water to get the desired reaction from the fluid. Additionally, the team plans to experiment
extensively with the ferrofluid and different types of liquids to determine which setup will
provide us with the desired results.
Risk: There could be issues programming a microcontroller using the affiliated microcontroller
software language.
Contingency: Our group members are well versed in various other software languages that
could potentially be compatible with microcontrollers.
Risk: The team may run into issues constructing certain hardware components such as the
Plexiglas container for the ferrofluid.
Contingency: There are multiple resources available, including the faculty at the University of
Portland, the design project technicians, or at worst the library, and online sources to help.
CONSTRAINTS
Below is a detailed explanation of how this invention and use of the product may impact
individuals and society for the following realistic constraints:
Technical: This product could be of interest to companies in that there isn’t really anything like
this commercially available at the moment.
Economic: Economically, this product has minimal to no impact. The project budget is
estimated to be $270. If it were to be mass produced, costs to build one of these displays will
be considerably less, due to the fact that buying parts in mass would be cheaper.
Environmental: If this product were to be mass produced, there are environmental concerns. It
would use up valuable energy resources, and the components, after use, are not easily
recyclable.
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Social: Socially, this product could have an impact, in so far as it is a product that could appeal
aesthetically to young adults of high school and college age who are interested in science or
music.
Political: This product in no way relates to, or affects, the political world.
Professional: The completion of this product will reflect positively on the level of
professionalism maintained by Team Couch Street. It will reflect highly on the Team’s ability to
work as a cohesive unit, meet deadlines, test and troubleshoot a product, and ultimately
produce a quality product for a client.
Ethical: This product has no ethical impacts since it not dangerous to use. Even on a large scale,
a ferromagnetic fluid visualizer has no ethical constraints.
Legal: If the product were to be mass-produced for sale, it would be beneficial to consult a
patent attorney first and ensure that Team Couch Street is granted exclusive rights to the
product.
Health and Safety: The ferromagnetic fluid is dangerous if consumed, and it should be left in its
protective housing. Electromagnets can be damaging to other electronics so phones and
computing devices should be kept away.
Security: There aren’t any particular security concerns pertaining to organizations or individuals
that may be using or selling this product.
Manufacturability: This product would be relatively easy to mass-produce. The components
are easily available and not too difficult to assemble once initially designed and tested.
Sustainability: This product will hold up well over time and require minimal to no maintenance
to continue being operational over a period of several none of the materials used are difficult to
locate and purchase.
Standards: The product will need to meet the standards set by the client. If it were to go into
mass production, it would need to meet certain standards of reliability for the consumer.
Codes: The product will have to meet certain safety codes designated by the team and the
team’s advisors. These would include things such as ensuring all wires are properly insulated
and that there is no way for any potential user to be shocked or injured.
CONCLUSION
The ferromagnetic fluid visualizer is a new spin on an old idea. The microcontroller will be
collecting audio input, processing it, and displaying it using electromagnets and ferromagnetic
fluid. This document has laid out a time line for production of the prototype as well as
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preliminary design concepts and preliminary cost of production estimates. A visualizer should
be a challenging yet manageable design project for engineering college seniors. As a final
prototype, the ferromagnetic fluid visualizer should be an eye catcher for everyone whether
they be technologically inclined or not.
GLOSSARY
Arduino: is a single-board microcontroller to make using electronics in multidisciplinary
projects more accessible.
Electromagnet: is a type of magnet in which the magnetic field is produced by electric current.
Ferrofluid: is a liquid which becomes strongly magnetized in the presence of a magnetic field.
IC: (Integrated Circuit) is a microelectronic circuit manufactured on a thin substrate of a
semiconductor material such as silicon.
LED: (Light Emitting Diode) A semiconductor diode that emits light when a voltage is applied
to it and that is used especially in electronic devices (as for an indicator light).
REFERENCES
http://www.arduino.cc/
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