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Design Document
Shiley School of Engineering, University of Portland
EE/CS 480A Senior Design Project Preparation
Magnetic Manipulator
Team 125
Marley Rutkowski (Fall Team Lead), John Olennikov,
Chad Perkins, Benjamin Younce
Faculty Advisor: Dr. Robert Albright
Industrial Advisor: Andy McConnell
Client: Dr. Mark Utlaut
November 15th, 2013
1
Table of Contents
Page
Introduction ................................................................................................................................ 2
High-Level Architecture .............................................................................................................. 4
Construction Specifications ........................................................................................................ 6
Component Structure ................................................................................................................. 7
Software Architecture ................................................................................................................11
System Test Plan ......................................................................................................................12
Development Plan, Milestones, Assumptions, Risks, and Facilities...........................................13
Final Budget..............................................................................................................................13
Conclusion ................................................................................................................................13
Bibliography ..............................................................................................................................14
Glossary....................................................................................................................................15
Appendix A ...............................................................................................................................16
Figure 1. System Layout ............................................................................................................ 3
Figure 2. System Block Diagram ................................................................................................ 4
Figure 3. Electromagnet Layout ................................................................................................. 6
Figure 4. System Schematic ...................................................................................................... 8
Figure 5. Magnet Field Visualization .......................................................................................... 9
Figure 6. DC to DC Adjustable Voltage Regulator/ Power Supply DC Boost Converter
Schematic .................................................................................................................................10
Figure 7. 7805 DC Voltage Regulator IC Schematic .................................................................11
Figure 8. Software Components ................................................................................................12
Figure 9. User Interface Diagram ..............................................................................................12
2
Introduction
Team 125 has designed a magnetic levitation device that will manipulate a small metal
object, controlling its movement in a small area of vertical 1D space without any physical
interaction. The team hopes to further expand on this process to achieve controlled levitation in
2D space in which an object can be moved left, right, up and down.
Levitation will be achieved by switching the electromagnets on and off above the
levitating object to maintain its desired position. The system will monitor levitation position of the
object, and if it is below the desired position, the electromagnet is fully powered. It is powered
down again when the object is at the desired position. Stable levitation is achieved by repeating
this process very rapidly. The system layout is detailed in Figure 1. The user will be able to
adjust the desired vertical position of the levitating object. An Arduino microcontroller will
monitor the position of the object by decreasing the percentage of the time that the power to the
electromagnet remains on to allow the object to drop, and increasing this time to lift the object.
Team 125 hopes to expand the device to achieve horizontal movement by using a second
electromagnet positioned adjacent to the original one to pull the object to the side, eventually
achieving stable levitation under the second electromagnet.
Many examples exist of systems that have achieved levitation comprised of a single
electromagnet, coupled with a Hall Sensor at the tip of the electromagnet, and positioned above
a magnetic object. Team 125’s system will expand upon this idea with an added adaptability of
position control. Accurate manipulation of the object will require experimentation once the team
has the physical system of the Magnetic Manipulator set up. Achieving proper functionality at
the high speed at which the system will have to adjust electromagnet strength in order to
stabilize the magnet will the primary challenge of the system. It will have to be precise, and it will
be difficult to identify what is causing problems in the system. However, by choosing an Arduino
as the center of the team’s logical system, there will be opportunities to fine-tune the system to
work as desired. In the team’s finished project, the user will be able to control the levitation
movement using a computer connected by serial to the microcontroller, as well as manipulate
the levitating object in a pre-programmed movement pattern.
This concept could eventually be expanded to utilize additional adjacent electromagnets
to achieve levitation in a larger area, and possibly in 3D space. The device will serve as a
conceptual demonstration for a technology that can be applied to numerous fields, potentially
including manufacturing or even eventually in patient medical surgery.
In this document Team 125 will go over the Magnetic Manipulator design and how it will
be implemented. First, high-level architecture will be discussed; each of the system
components, their functionality, how they interact and how they fit the requirements of the
system. This document will then delve deeper into the component structure of the system,
giving details on how components will be designed and implemented. Team 125’s plan will be
detailed in the system test plan section. The project development plan, as well as the team’s
milestones, assumptions, risks, and required facilities, will also be discussed. Finally, Team
125’s final budget will be provided.
3
Figure 1. System Layout
4
High-Level Architecture
Team 125’s magnetic levitation system will require at least 9 major components: an Arduino
microcontroller, computer, electromagnet*, Hall sensor*, levitating object, power source,
transistor*, voltage regulator*, and an enable switch. The primary goal of Team 125 will be to
achieve controlled levitation under a single electromagnet in one dimension. Once this has been
completed, the team hopes to achieve controlled levitation in two dimensions by adding a
second electromagnet. The inclusion of a second electromagnet will require an additional set of
each of the control system components marked by an ‘ * ’, in order to control the second
electromagnet. Figure 2 is a block diagram of all of the system components and how they
interact. Further information on their functions and the specific parts being used can be found
below.
Figure 2. System Block Diagram
1-Arduino Microcontroller:
The Arduino microcontroller is the central brains of Team 125’s system. It is responsible
for interpreting commands from and providing information to the user, tracking the levitation of
the object through the Hall sensor, and controlling the power given to the electromagnet via the
transistor.
 User input data will be received by the Arduino as bytes sent over a serial wire by the
computer. When commands are available in its buffer, the Arduino will read and interpret
them in order to determine how the state of the system should be affected.
5



System state data will be encoded by the Arduino and sent over serial to the computer in
order to provide the user with information to improve system control.
Hall sensor data will be read in by the Arduino on an analog pin. Its value will be used to
track the position of the levitating object at any given time.
The levitating object position will be used by the Arduino in order to determine how to
control the electromagnet given the present position of the levitating object, the desired
position, and the change since the last measurement.
2-Computer:
The computer will serve as the user interface for the magnetic manipulation system. The
user will be able to input commands into a custom GUI which will be encoded and sent over
serial to the Arduino to be executed. The GUI app may also have to buffer commands to make
sure that they are not sent too fast for the Arduino to read because it has a serial queue of
limited size. The GUI should also decode and display pertinent data about the system state,
received from the Arduino over serial.
3-Electromagnet(s):
The electromagnet creates the magnetic field that interacts with the levitating object
keeping it in place. It is activated and deactivated by the transistor that controls the power
provided to it. The electromagnet must be powerful enough to maintain levitation of our object
within a maximum range of at least 2 inches.
4-Hall Sensor(s):
Hall sensor data will be used to gather information on the position of the levitating object.
A Hall sensor varies its output voltage in response to the magnetic field; the Arduino will monitor
this data on one of its analog input pins. From this information the Arduino will be able to
extrapolate the position of the levitating object at the given time. The Hall sensors must be
strong enough to accurately sense the magnetic flux of a ferromagnetic with an induced charge
strong within a 2-inch range.
5-Levitating Object:
This is the object that the system is working to levitate. It has a force exerted on it be the
field of the electromagnet which counters the force of gravity, and the Hall Sensor reads the
value of the magnetic field produced by this object to provide information on its position. The
team will design the Magnetic Manipulator to levitate a 1/2 inch diameter by 1/8 inch thick disc
grade N48 Iron-Boron Neodymium magnet.
6-Power Source:
The power source provides the energy necessary to activate the electromagnets. Team
125 will use a power source that meets the power requirements of the electromagnets. In
preliminary lab tests using a physical concepts demonstration magnet team 125 was able to
estimate the amount of power needed to lift the magnets of interest at 2 inches. Tests showed
that lifting at such a range with the test electromagnet required about 20W of power (2.92V at
6.1A). Therefore based on current research and experimentation the Magnetic Manipulator
6
system will require a 12V DC power supply that can supply at least 20W of power. Until further
notice, the team will use a supply from the University of Portland Senior design laboratory.
7-Transistor(s):
A transistor will be necessary to switch the power to the electromagnet on and off. The
transistor will take power, provided by the power source, through the power regulator. The
transistor will then supply power to the electromagnet when activated, and supply no power
when not activated. A digital control signal from the Arduino will be used to activate and
deactivate the transistor.
8-Voltage Regulator(s):
The voltage regulator maintains a constant voltage supply to the system, independent of
the power supply and the current load. It takes power in from the power source and provides
power to the transistor circuit that is responsible for controlling power supplied to the
electromagnet. It may be necessary to use an adjustable power regulator so that the output
voltage will be adjusted by the Arduino via an analog signal. The technical specifications of the
team’s voltage regulator will depend on the power supply and electromagnets that Team 125
chooses to use in the system.
9-Enable Switch:
Team 125 will include a physical switch that can be used to enable and disable the
levitation system. The switch will be connected to one of the Arduino’s digital input ports. When
disabled, the electromagnets will have no power supplied to them. When enabled, the system
will work as specified.
Construction Specifications
System Layout:
Figure 3 depicts how the team plans to lay out the electromagnets and Hall effect
sensors if system is extended to execute controlled levitation in two dimensions. For the team’s
primary one-dimension goal, one of the electromagnet and Hall sensor systems will be utilized.
Figure 3. Electromagnet Layout
7
Stand:
Team 125 will build a stand to suspend the electromagnets above the area of
manipulation. This stand must be sturdy, but it must also allow for an unobstructed view of the
Magnetic Levitator at work. The team must also be able to place the system electronics
somewhere that the magnetic fields generated by the electromagnets will not interfere with
them. In order to achieve these goals, the team will use a hangman-style stand that will allow for
an unobstructed view at three out of four angles. With this design, the electronics will be placed
on the base of the stand of the Magnetic Manipulator, opposite of the levitation area. The
primary construction material of the stand will be Plexiglas. Constructing the stand from
Plexiglas will allow the system to have an unobstructed view from the back. Figure 1, provided
above, demonstrates how the system will look.
System Dimensions:
 The maximum distance of magnetic manipulation control that the system should achieve
is 2 inches, so the electromagnets will have to be mounted high enough to allow for
improvement from this goal with some leeway. However, the levitating magnet will not be
able to move too close to the electromagnet or else it will be attracted to the
ferromagnetic iron core, so our manipulation range will be approximately 0.5-2 inches.
By building the mounting structure so that the electromagnets are about a foot above the
base of the mount, there will be enough room for improvement on the team’s 2-inch goal.
 The electromagnet(s) will have to be far enough away from the vertical part of the stand
so that the movement of the levitating object will not be obstructed. The first
electromagnet will be placed 2 inches from the vertical part of the stand to allow for
enough space. This will put the entire top structure, or overhang, of the stand at
approximately 5 inches.
Component Structure
This section details the structure of each component of the magnetic manipulator. It
displays the parts that have been chosen by Team 125 and how they will be effectively
integrated into the system. Figure 4 is a system schematic showing all of the system
components and how they are integrated.
8
Figure 4. System Schematic
Arduino:
Team 125 will use an Arduino Due to control the Magnetic Manipulator system.
Maintaining stable levitation will require very rapid adjustments to the magnetic field supporting
the object, and the Due contains the quickest processor of all of the Arduino microprocessor
boards. Unlike the other boards it utilizes an Arm processor with a clock speed of 84 MHz,
which will allow the system to have a high turnover rate. The Due has 521kB if flash memory
available to the user, as well as 96 kB of SRAM which will be plenty of memory since the
system will not need to store much information. The board has 54 digital I/O pins, 12 analog
input pins and 2 analog output pins, many more than the teams’ system will require.
A key difference of the Arduino Due and the other Arduino products is that it has an
operating voltage of 3.3V for all of its pins, whereas other Arduinos run on 5V. This means that
all of Team 125’s components that interact directly with the Arduino Due must also operate in a
0-3.3V range. This includes the Hall sensor(s) and transistor(s) that will have to be integrated
with the board. The Analog input pins on the Due are 12 bit (i.e. 4096 different values),
representing values in the range 0-3.3V, meaning they have an accuracy of approximately
0.806mV.
Electromagnet(s):
Team 125 will use a Ginsberg Solenoid/Electromagnet with a steel core. The type of
electromagnet chosen is important because it will affect how the levitated magnet will respond
to its magnetic field. The solenoid measures 8” x 4” x 4” with a ¾” x 6” removable steel core. It
will be powered by a 12V DC input and provide more than enough force to lift and suspend a
small neodymium magnet in midair. The electromagnet will be powered by a transistor circuit
that activates and deactivates based on the negative feedback of the system. The
electromagnet is expected to maintain a minimum distance of 2 inches between itself and the
neodymium magnet that it levitates.
9
The positive lead of the electromagnet will be connected to the positive out of the
voltage regulator, and its negative terminal will be connected to the collector of its controlling
transistor. It will also be connected in parallel with a diode to dissipate backflow current with its
cathode wired to the positive lead and its anode to the negative lead (and transistor collector).
Hall Sensor(s):
The magnetic manipulator will utilize an A1326 linear Hall effect sensor with analog
output. This sensor can be powered by the Arduino at 5V and will have a quiescent voltage
output of 2.5V with a sensitivity of 2.5mV/G. However since the output voltage range of this IC is
0-5V a voltage divider to bring the range down to 0-3.3v will be needed, this will decrease the
sensitivity to 1.67mV/G. Such a divider circuit will be made with a 1kOhm and 2kOhm resistors
in series, the Arduino monitors the voltage between the resistors through an analog input pin.
The Arduino Due’s analog input pins have an accuracy of about 0.806mV per integer; therefore,
using this sensor, Team 125 will be able to interpret the strength of the magnetic field at an
accuracy of approximately 0.48G. If in testing the team finds that this is not accurate enough,
the Hall sensor signal can be amplified and a voltage divider can be used to get more accurate
data.
Levitating Object:
Team 125 will design the Magnetic Manipulator to levitate a 1/2 inch diameter by 1/8
inch thick disc grade N48 Iron-Boron Neodymium magnet. Such a magnet weighs
approximately 3g and has a pull force of 6.1lb (placed directly against steel). According
experimenting done by K&J Magnetics the magnetic field strength of such a magnet 2 inch
away on axis is approximately 6.8 gauss. Figure 5 displays the shape and strength of the
magnetic field. Neodymium magnets are the strongest permanent magnets in the world, which
makes them perfect for our application where the Magnetic Manipulator will require the greatest
ratio of field strength to mass in order to support the object across a large air gap. Team 125
hopes to be able to extend the project to the levitation of other sizes/types of magnets and even
ferromagnetic materials (at smaller ranges), once the team has achieved its goal with the
Neodymium magnets specified above.
Figure 5. Magnet Field Visualization
10
Transistor(s):
A TIP 120 NPN transistor will be used in the Magnetic Manipulator. The maximum
collector-base voltage of the TIP120 is 60V, the DC collector current is 5A, and collector
dissipation (TC=25°C) is 65W. This is way above the system specifications where the Magnetic
Manipulator is expected to run on around 12V with less than 1A, meaning that the power of its
system would be around 12-24 watts. The maximum collector cut-off current of the transistor is
0.5mA, and the base-emitter on voltage is 2.5V which can be easily supplied by the Arduino
Due outputs which can provide 3-15mA, and have a maximum voltage of 3.3V.
The transistor will be wired with its base connected to the Arduino through a 1KOhm
resistor. The emitter will be wired to ground, and the collector will be wired to both the negative
lead to the electromagnet and the anode of a diode. The diode will be wired in parallel with the
electromagnet in order to prevent any backflow current created when the electromagnet turns
off from propagating back into the system. Therefore, its cathode will be connected to the
positive lead of the electromagnet.
Voltage Regulator(s):
Team 125 will use a high power DC-to-DC adjustable voltage regulator/power supply DC
boost converter. The regulator is present in the system to stabilize the voltage from the source
and raise the voltage and/or power of the power source. The voltage regulator has a range of
4.5-32V at the input and is capable of 5-42V at the output. The current limit through the
regulator is 6A. The power output capability of the boost converter is much higher than the
Magnetic Manipulator will need, but the power boost converter in the regulator will give the
operator the ability to raise or lower the voltage supplied by the source without changing the
current supplied to the electromagnet.
The voltage regulator will be wired between the power switch and the electromagnet.
The second pole of the power switch will be wired to the positive input of the voltage regulator.
The positive output of the voltage regulator will be connected to the positive lead of the
electromagnet.
The voltage regulator/boost converter that the team will use is a purchased product that
is a complete circuit on its own. A schematic of the device is shown in Figure 6 below.
Figure 6. DC to DC Adjustable Voltage Regulator/ Power Supply DC Boost Converter
Schematic
11
Figure 7 displays the schematic of the 7805 voltage regulator IC that is an element of the
voltage regulator/boost circuit.
Figure 7. 7805 DC Voltage Regulator IC Schematic
Enable Switch:
Team 125 will use a toggle switch with ratings of up to 5A and 28V DC, manufactured by
TE Connectivity. This is much more power than the Arduino will ever require, so the switch
should integrate effectively into our system. The system enable switch will be wired with a
positive lead to 3.3V and a negative lead to a digital “in” on the Arduino. The team will also wire
a switch in series with the power source and power regulator so that an operator can quickly
shut off power in case of emergency.
Software Architecture
The user can affect the circuit only by interacting with the provided interface. The user,
through the interface, can enter an input that decides how the object should be raised or
lowered. The interface then communicates with the Arduino chip and interprets the user data.
The Arduino, in response, sends back present statistics that will be displayed to the user via the
interface. The Arduino monitors the input values of the Hall sensors in the circuit and
manipulates the pulse frequency to manipulate the object. The Arduino chip also runs
calculations to determine the strength of the magnetic field and calculate the levitating object’s
distance from the magnets.
12
Figure 8. Software Components
User Interface
The user interface will be designed using the Processing programming language. As
shown in Figure 9, the interface will consist of a data and a user input container. Section 1
contains and displays all the relevant data related to the program. The user-set “Pulse
Frequency” is shown in a text view as shown in Section 2. Section 3 and Section 4 are also text
views that display the calculated values for the “Magnetic Field” strength and the distance that
the object is from the magnets. Section 5 contains components which allow the user to interact
with the device. If the users decide to raise or lower the object, they would press either the “UP”
button, as shown in Section 6, or the “DOWN” button, as shown in Section 7.
Figure 9. User Interface Diagram
System Test Plan
TEST 1. Steadily levitate one Neodymium magnet.
1. Turn on the power source.
2. Carefully place the magnet about 1 inch directly below the electromagnet in mid air.
13
Note: For a passing result the magnet should levitate steadily underneath the
electromagnet.
TEST 2. Use the GUI to steadily move the Neodymium magnet vertically, up and down.
1. With the magnet statically levitating from TEST 1.
2. Use the up button on the GUI to move the magnet upward 0.5 inch.
Note: For a passing result the magnet should move steadily upward toward the
electromagnet 0.5 inches and settle, levitating steadily 0.5 inch higher than it was
previously.
3. Use the down button on the GUI to move the magnet downward 1 inch.
Note: For a passing result the magnet should move steadily downward away from the
electromagnet 1 inch and settle, levitating steadily 1 inch lower than it was previously.
Development Plan, Milestones, Assumptions, Risks, and Facilities
Refer to the Requirements and Functional Specifications v1.0 document for a complete list of
Team 125’s current milestones, assumptions, risks and facilities required.
Final Budget
See Appendix A - Final Budget (p16)
Conclusion
Team 125 will strive to develop a system that will achieve stable magnetic manipulation
controllable in at least the vertical plane. The team has chosen a flexible design, so after
achieving this result Team 125 hopes to have the opportunity to extend our goals into further
dimensions. The Magnetic Manipulator’s design will allow the user to have a high level of
control, but still have insight on how it is working. In developing Team 125’s system, the team
will face lots of trial and error testing in order to develop the code to make the device work
properly. Therefore, one of the team’s biggest challenges will be the testing of the Magnetic
Manipulator, and the potential of accidentally damaging system components. Team 125 will
order extra parts so that if components are damaged, progress is not greatly inhibited. Although
the team’s ultimate goal of 2D magnetic manipulation is a stretch on the skills of each team
member, Team 125 has provided itself with goals of increasing difficulty and achievable
milestones that will lead to the ultimate success of the Magnetic Manipulator.
14
Bibliography
Arduino. 2013. http://arduino.cc/en/Guide/ArduinoDue (accessed September 5, 2013).
DigiKey. http://www.digikey.com/ (accessed September 7, 2013).
HacknMod. 2013. http://hacknmod.com/hack/how-to-controlled-levitation-using-magnetsmicrocontrollers/ (accessed September 15, 2013).
Instructables. 2013. http://www.instructables.com/id/Use-Arduino-with-TIP120-transistor-tocontrol-moto/
(accessed September 11, 2013).
Instructables. 2013.
http://www.instructables.com/id/Controlling-solenoids-with-arduino/?ALLSTEPS
(accessed October 27, 2013).
Mekinikuv Blog. 2009.
http://mekonik.wordpress.com/2009/03/17/arduino-magnet-levitation/ (accessed October 30,
2013).
SparkFun. https://www.sparkfun.com/products/9312 (accessed September 4, 2013).
YouTube. http://www.youtube.com (accessed September 1, 2013).
Zelcom. 2013.
http://zeltom.com/products/magneticlevitation (accessed October 27, 2013).
15
Glossary
Arduino: A single-board microcontroller to make using electronics in multidisciplinary projects
more accessible.
Electromagnet: A type of magnet in which the magnetic field is produced by electric current
flowing through coils.
Enable Switch: Can be switched on or off to provide high/low logic.
Hall Sensor: A transducer that varies its output voltage in response to a magnetic field.
Team 125: A Senior Design Project team consisting of Marley, John, Chad, and Ben.
Magnetic Field: A region around a magnetic material or a moving electric charge within which
the force of magnetism acts.
Magnetic Levitation: A method by which an object is suspended with no support other than
magnetic fields.
Magnetic Manipulator: A device constructed by Team 125 that sustains controlled levitation of
a small object.
Neodymium Magnets: A member of the rare earth magnet family. They are called "rare earth"
because Neodymium is a member of the "rare earth" elements on the periodic table.
Neodymium magnets are the strongest of the rare earth magnets and are the strongest
permanent magnets in the world.
Power Source: A device that supplies electric power to an electrical load.
Pull Force: The holding force of a magnet when it placed up against a steel plate. This value is
determined in a lab with a pull force tester.
Transistor: A semiconductor device used to amplify and switch electronic signals and electrical
power.
Solenoid: A coil wound into a tightly packed helix used to create magnetic fields.
Transistor: A semiconductor device with three connections, capable of amplification in addition
to rectification.
Voltage Regulator: A device that automatically maintains a constant voltage level.
16
Appendix A
Final Budget
Item
Qty
Unit
Price
Cost
Supplier
Webpage
Arduino Due
2
$46.95
$93.90
Virtuabotix
https://www.virtuabotix.com/pr
oductpage/7640152111228/
Hall Sensor
A1326LLHLT-T
5
$2.20
$11.00
Digikey
http://www.digikey.com/produ
ct-detail/en/A1326LLHLTT/620-1403-1-ND/2639995
TIP120
Transistor
5
$0.66
$3.30
Digikey
http://www.digikey.com/produ
ct-detail/en/TIP120/TIP120ND/1052441
Bread Board
1
$7.95
$7.95
Virtuabotix
https://www.virtuabotix.com/pr
oductpage/608641373295/
Toggle Switch
2
$3.17
$6.34
Digikey
http://www.digikey.com/produ
ctdetail/en/A101SYZQ04/4501523-ND/1021810
Power
2
11.20
22.40
AliExpress
http://www.aliexpress.com/ite
m/DC-Adjustable-VoltageRegulator-DC-4-5-32V-to-542V-High-Power-IndustrialPowerSupply/678569187.html
Radial Magnet
5
$1.28
$6.40
Digikey
http://www.digikey.com/produ
ctdetail/en/1%2F2%22DIA%20
X%201%2F8%22THICK/4691002-ND/555326
10 N48
Magnets
2
$7.96
$14.92
Amazon
http://www.amazon.com/Neod
ymium-Magnets-inch-DiscN48/dp/B001KV38ES
Solenoid
2
$26.98
$53.96
Teacher
Supply
http://www.teachersupplysour
ce.com/product/63947/americ
an-educational-
Regulator
#090480
17
products/ginsberg-scienceandlabware/electricity/ginsbergsolenoid-electromagnet-withcore/
Diode 1N5817
5
$0.44
$2.20
Digikey
http://www.digikey.com/produ
ct-detail/en/1N5817T/1N5817DICT-ND/190530
*Stand
Expenses
1
$40
$40
Tap Plastics
http://www.tapplastics.com
Shipping Cost
Digikey $7.49-$9.75 (depending on weight)
Virtuabotix FREE
AliExpress FREE
Amazon $7.99
Teacher Supply $15.87
Total cost of parts: $262.37
Total cost of shipping: $33.61
Total cost of project: $295.98