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Final Documentation - University of Central Florida

1. Length 1 in x aa width 25 Hin E 0 93 b Force vs Distance Thickness 125 in 2 Distance 2 H in x 8 2 Calculate 1 2 distance in Click for larger chart Clear Magnetic Field at 0 2in on 877 Gauss axis See the Permeance Coefficient Magnetic Field Pc 0 56 Figure 4 6 Magnetic calculator showing repelling force between two magnets 1 x 25 x 125 of grade N42 at a distance of 0 20 Also shown is the strength of the magnetic field in Gauss and the Permeance Coefficient Reprinted with permission from K amp J Magnetics INC Since the levitation through a halbach array means the vehicle would not be touching the track this means that friction between the vehicle and the track would be non existent In terms of drag a halbach array can reduce the drag from the eddy current As the magnets pass through the magnetic fields at a faster rate the drag from the eddy current increases Halbach arrays are of a low magnetic field Since they are not electromagnets the potential dangers of using electromagnetic levitation are non existent Finally the nature of the halbach array dictates that it is low power Traditional halbach arrays in use today make use of passive coils The projected described in this paper makes use of permanent magnets In either case there is miniscule power consumption by the halbach arrays The main type of Halbac
2. Financing Component 50 00 Track materials 450 00 Track magnets 100 00 Vehicle Materials and Drive system 40 00 MCU 5 00 EM detection 10 00 Power source 16 00 Wireless Connectivity 20 00 Other Total 691 00 Table 7 2 4 Financial Table 117 Financing inancing Z Figure 7 2 4 Financing 7 3 Bill of Materials The bill of materials will be quite extensive and the majority of the cost will be due to the Neodymium magnets used for the track drive system Final Costs Figure 7 3 itemizes our final budget and the costs spent on the individual products Products Wood Material 30 00 Neodymium Cylindrical Magnets 250 00 Neodymium Rectangular Magnets 180 00 Fiber Board 10 00 Acrylic Material 14 00 Copper Wire 20 00 Aluminum Channel 10 00 Breakout Board 14 95 H Bridge Motor Drive 7 00 IC Hall Effect Sensors 13 76 MCU parts 15 00 Bluetooth Module 17 95 PCB 20 00 Other 100 00 Total 702 66 Figure 7 3 Final Budget 118 Appendices Copyright Permissions Re Permission for image use REPLY E REPLYALL FORWARD A r k d James Jordan lt james jordan cox net gt ii Tue 7 9 2013 12 48 AM Drafts To William Schiller lt wschiller knights ucf edu gt Cc jamesrpowell32 gmail com janedanby aol com Certainly you may use the image Send us a copy of your paper when it is complete Jim Jordan Original Message From
3. Hardware requirement Bluetooth adaptor on all the devices connecting with each other Wireless adaptors on all the devices of the network a wireless router and or wireless access points Range 5 30 meters With 802 11b g the typical range is 32 meters indoors and 95 meters 300 ft outdoors 802 1 1n has greater range 2 5GHz Wi Fi communication has greater rangethan SGHz Antennas can also increase range Power Consumption Low High Ease of Use Simple to use Can be used It is more complex and requires to connect up to 7 devices configuration of hardware and at a time easy to switch software between devices or find and connect to any device Latency 200ms 150ms Bit rate 2 1Mbps 600 Mbps Table 3 2 3 2 Reprinted with permission from diffen com 34 3 2 4 Electromagnets Linear motion will be achieved through the use of electromagnets An electromagnet can be created by simply connecting a current source to both ends of a conducting wire which will induce a magnetic field around the wire This project will use electromagnets to propel our vehicle forward with a steady acceleration to achieve a velocity of around 1mph A key difference between electromagnets and permanent magnets is that the polarity of electromagnets can be manipulated to the user s preference Understanding the properties of the magnetic field created is essential to design of the electromagnets Th
4. 53 permanent magnets This track design is a mix of the EDS system and Inductrack design This design consisted of a track that was fitted with both permanent magnets on the top of the track and on the sides Both magnet arrays would be arranged in a Halbach array in order to direct the magnetic field towards the car at all times Another difference is that with this track the vehicle would be fitted with a 3 phase motor system consisting of copper solenoids The solenoids would interact with the magnets alternating poles to create the propulsion needed No control system is needed as the vehicle is levitating at all times and there is no need for any type of magnetic shielding as these permanent magnets are not super cooled and thus do not create such an immense magnetic field This design is not without its flaws either Cost Labor intensive Types of magnets Dimensions of the track Again cost becomes an issue with the permanent magnets Since both sides of the top of the track and both sides of the sides of the track must be lined with permanent magnets the cost of just those magnets alone will be quite high The magnets must also be oriented correctly to produce the proper levitation and propulsion that the project demands which increases the amount of manual labor for the project The dimensions of the track are also under more scrutiny as the dimensions need to be able to accommodate the magnets and hold them adequately Too much
5. Effect sensors connected to the analog ports of the Atmega328 AO A1 and A2 We will have the input be saved as a variable whenever we need to read the sensor The code our group will use will be variable Analogread port This means our MCU will take the signal being received by whichever port that is in the parenthesis and save it into the variable Obviously for our actual programming we will have variables and ports correctly established for efficiency and organization Once we have the current analog value saved into a variable of our choice we are free to use it however we choose Atmega328P Take input Allegro A1301 alog_inO Analogread AQ Figure 4 2 1 2 Hall Effect Block Diagram 76 4 2 1 3 Microcontroller Conversion function Yes digitalWrite pins HIGH digitalWrite pin7 LOW Yes Figure 4 2 1 2 Control Flow chart The functioning of the microcontroller is a crucial portion of the project The MCUs job is take the input it received from the Hall Effect sensors and convert that information into digital outputs that will be in charge of controlling the solenoid magnet polarities This means that it will take an analog value and turn it into digital outputs The pattern it will follow is based on the three phase sinusoidal diagram Figure 3 4 Interaction between sensors and track magnets If the analog input has just passed the 5v mark it means that the specific sensor has just passed an
6. IDE Eclipse IntelliJ Netbeans Xcode Programming Language Java Objective C Interfacing with external Very open Mostly Apple only Devices devices Bluetooth Support Any Bluetooth enabled Only devices supporting device Bluetooth 4 0 LE Example Source Code Numerous Examples Very few Related to Project Interface development Less User friendly More user friendly Testing on Real Device Free 99 and must join Apple Developer Program Table 3 2 2 2 30 3 2 2 3 Android Smartphones The remote controller has to be updated with the latest technology based on the group s project intentions Since the group is using an Android powered smartphone to act as the remote controller for the system there are many phones to consider Of the latest smartphones released that run the latest Android version of open GL 4 3 there were three prominent choices out there These are the HTC One the Samsung Galaxy Note 2 and the Samsung Galaxy S4 All three of these present prominent choices for use with our system Analyzing all of their features the group understands that the most important features are those of its Bluetooth capabilities and processing speed HTC One The HTC One brings a 4 7 inch screen for user interfacing with the Operating System It carries a 1 7 GHz quad core processor for processing speed and power and its one of the first of its kind to bring four cores to the CPU The Bluetooth capabilities of this phone are the latest whi
7. The budget for the track is in the realm of 500 00 A small portion of the budget 150 00 was allocated to the track materials themselves This will cover the cost of the prototyping building materials and any extra materials that are needed during the construction of the track The remaining 350 00 of the track budget was allocated to the magnets The permanent magnets that make up the levitation 114 and propulsion are the bulk of the cost of the track and the entire project as a whole Financing for the track materials and magnets will come from the members of the group itself The group has attempted to contact distributors such as e Master Magnetics INC www magnetsource com e K amp J Magnetics INC www kimagnetics com e Lowes e Home Depot e eBay In summary e Track budget 500 00 e Track materials allocation 50 00 e Permanent magnet allocation 450 00 7 2 2 Vehicle budget and finance Like the track the design process of the vehicle resulted in breaking down the vehicle into subsections for budget allocation Vehicle materials Chassis Pine Circuit housing Acrylic nonconductive material Levitation magnets 4 Neodymium permanent magnets Drive system Solenoids Copper wire The vehicle itself is not as costly as the track as it is made up of relatively inexpensive components Regardless the group felt to allocate 100 00 towards the materials of the vehicle This amount would cover the c
8. Bluetooth enabled devices The client contacts the server or the microcontroller in order to make use of its resources such as its CPU and Data Storage More specifically to the groups system the smartphone will make use of the microcontroller s ability to communicate directly with the vehicle and the information it holds about the vehicle and track In the typical client server model the method through which communication occurs is request response In that the client sends a request and the server sends back a response This group s model is going to be variably different The client the smartphone will only send one request The rest will be commands where no actual response is needed from the server to the client A response is needed but the effect will be on the vehicle itself So a total of three general commands with no direct response needed from the android smartphone remote 95 controller will be send and only one request where a response will be needed from the microcontroller 4 5 4 Commands Exchanged There are three main commands that will be executable from the smartphone to the microcontroller through the Bluetooth module These commands will be e Forward e Back e Stop All of these commands will be identified through integers There is a range of seven integers that will be used to identify each specific command The range of integers will be from 0 to 6 The first command forward will be identified by the nu
9. Specification Description Dimensions 26 0 mm x 13 5 mm x 2 7 mm Weight 1 2 g ELECTRICAL CHARACTERISTICS Specification Description Supply Voltage 3 0 3 6 V DC Working current Depends on profiles 30 mA typical Standby current disconnected lt 0 5 mA Temperature 40 C to 85 C ESD JESD22 A224 class 0 product Humidity 10 90 non condensing 23 Using the specs above we can see that the RN 52 meets all the requirements of our project The dimensions are small enough to fit on the maglev vehicle but not too small to balance safely The weight is not too heavy and will not limit the movement of the vehicle The voltage and current characteristics fit the design perfectly and will allow for easy implementation An operation range of 10 meters will be more than enough to control the device successfully The functioning temperature will easily stay inside the required functioning temperatures With all of the difference interface possibilities we know that we will be able to connect efficiently ooon OW ovrwrwwrwrsss qgoaqQqqaqaqaaa ge eer er Ae Abeer 4 O00 000 1 GND GND 2 GPIO3 SPKR_L 3 GPIO2 SPKR_R 4 AICO0 SPKR_L 5 GPIO4 SPKR_R 6 GPIO5 AGND 7 GPI012 MIC_R 8 GPI013 MIC_L 9 GPIO11 RN52 MIC_R 10 GPI010 Top View MIC_L 11 GPIO9 MIC_BIAS 12 USBD LEDO 13 USBD LED1 14 UART_RTS SPI_MOSI 15 UART_CTS SPI_SCK 16 UART_TX SPI_MISO 17 UART_RX eee
10. The interface through which the user will control the system is directly through the remote control which has been established to be an android smartphone There are many examples of applications of reference that do a similar task as the group s intended function for developing an android application which is communicating with an external device through Bluetooth communication For this specific project a specific application with a specific task is needed In order to access the Bluetooth libraries from Android Plugin permission must be granted in the manifest file of the root directory The manifest brings the important information about the application to the Android system This information is necessary before the system can execute any of the code Some important aspects of the manifest file are as follows e t possesses the Java package which serves as an identifier for the application e Used to describe all of the components including services activities broadcast receives etc e Declares which permissions the application has to have for it to access guarded sections of the programming interface and comingling with other applications e t also lists others permission needs to interact with this application s components e Declares the minimum level of Android application programming interface that this application needs e lt also lists the necessary linked libraries that are accessed by the application What the group s
11. a possible analog remote controller Instead the control will come from an Android phone through an RN 42 Bluetooth module This chip only has four pin connections that will be utilized Receive input UARTRX and transmit output UARTTX VDD and ground The RN 42 bluetooth module runs on a 3 3V supply and as shown in figure 5 1 3 it is connected to the 3 3V pin on the Arduino board For figure 5 1 3 the RN 41 is the closest similar part to the RN 42 that could be found the differences are not important enough to warrant a change in schematic ARDUINO UNO R3 7 j T S lt Tf Figure 5 1 3 Connections between the Arduino and RN41 NN 100 PADI Palereld aly N rocco Figure 5 1 3 1 Total Eagle Schematic UNO R3 Perii PADS N758410 ee at tanks Y Ae rele ARMOR AMEE WK AMI ih ht 22 ta Sr oF yi ROLL W ts WW tas WMG W RY ELUETOOTH Al t ako 101 5 2 Arduino ProtoShield PCB surface The Arduino ProtoShield allows for circuit prototyping on a compact and stackable surface The ProtoShield mounts on top of the Arduino Uno board by utilizing stackable headers The convenience of this allows all the Arduino UNO board pins to be raised to the Protoshield level for circuit design The Arduino ProtoShield kit which is roughly 10 depending on the online vender comes with the following 1 ProtoShield ba
12. biased switches the direction of current flow through the MOSFETs and LED s is controlled by S1 and S2 used green LED s in this Multisim simulation to illustrate the direction of current flow when the switches are toggled There are two scenarios with this circuit when 1 is high and S2 is low LED2 turns on and LED1 is off In other words the current is flowing from left to right through the load which in our case would be the solenoid The second scenario would be when S2 is high and S1 is low this allows current to flow through LED1 and turn it on The act of turning on LED1 would describe current direction from right to left through the load We need a decent amount of current to create the amount of magnetic pull we need for the solenoid For this circuit have generated about 9 A although used an unrealistic voltage for VCC VCC Should be around a 9V DC source instead of the 50V shown So in order to implement this circuit with the parameters specified we will consider purchasing an H bridge IC from TI or a similar vendor ELTE Eg J E GS be fey CA Gaz set Rarinnt BR b teidan mantel Figure 3 2 6 1 Scenario 1 S1 high and S2 Low gt current left to right through load 37 Multimeter XMM2 x 856 857 mA fad E 2 fe Wa OA 5 lt lt Mul
13. demonstration of the maglev vehicle While the circular track had the better demonstration capabilities the straight track provided the ease of construction and would allow for viewers for better observation With the NASCAR like track the maglev vehicle can demonstrate its high speed capability on an infinite track while showcasing the linear motion on the straightaways The difficulty of construction is limited to the curved corners of the track and transporting the track is made simple due to its curved shape 56 Levitation array Levitation array Figure 4 3 The rough sketch of the track design that was ultimately decided upon Shown is the top view with the segmented rows to indicate the permanent magnet levitation arrays The large arrows in the track show the direction of motion that will be demonstrated when the vehicle is in operation The nature of the track allows for constant motion as it is an infinite track The vehicle will be able to travel both forward and backward to showcase the entire range of linear motion The dimensions of the finalized track are as follows e Straightaways 2ft e Arc sections 1ft diameter e Angle of curvature for arc length 90 A 2 foot long straightaway is sufficient length to showcase the high speed capabilities of the vehicle The arc lengths were designed to be a little longer to facilitate an easy transition to the adjacent straightaway This way the speed can remai
14. each other and fly into someone s eyeballs 4 1 6 Building Plan for First Prototype This step by step procedure gives a rough building plan for the 1 prototype the team designed for the car By no means should this be considered a final and exact approach to the end product This procedure also only details the car foundation for which will house the solenoids circuitry and PCB board MCU Bluetooth 1 Cut wood blocks to specified dimensions if not already done Make sure the pieces of board are roughly 2 to wide 2 Cut the two 7 x 2 wood pieces into four 3 5 x 2 sections this is done to leave a space for the roughly 2 wide aluminum channel that is to be fit across the bottom of the body piece 3 Since now the wood pieces exceed the desired dimensions cutting down to size so that the extensions from the main body are only 1 5 can be done 4 Connect the four sections to the corners of the body piece by drilling non ferrous screws The screws should be small in length not more than 7 the width of the board Wood glue could also be used which might produce better results than the screws 5 Next it s time to attach the magnets to the four corners of the car This needs to be done with an extreme adhesive like a two part epoxy It is important to keep other magnets away while the adhesive is drying Some important tips for gluing Neodymium magnets were found from K amp J Magnetics website e Alw
15. in between The coils will be wound tightly in order to achieve the greatest possible magnetic field which will result in greater repulsion attraction hence more speed For a solenoid without a ferromagnetic core the magnetic field can be calculated with the following equation Where u is the permeability of free space N is the number of turns is the current and L is the length of the wire section B Uni T For the solenoid to function similar to the permanent magnets on the track the wire must carry a substantial current around 500 mA and the turns must be closely spaced Then a uniform magnetic field should be produced within the interior region creating poles on both ends of the cylindrical coil as shown in Figure 3 2 5 Exterior Interior Figure 3 2 5 Tightly Spaced turns vs loosely spaced turns of a solenoid Reprinted with permission from Kshitij School The solenoids are positioned on the car itself which will be placed in a track configuration of alternating polarity permanent magnets in a Halbach array Due to the price of copper the selection of the wire gauge came down to an affordable 30 AWG 36 3 2 6 H Bridge Circuit The solenoids need a circuit that switches the direction of the current through the windings The most effective way of sending current in either direction is creating an H bridge circuit A basic H bridge circuit utilizes 4 MOSFET s two PMOS and two NMOS These MOSFETs act like current
16. of funding The straight track offered decreased design complication as it only involves one straight section With the exemption of the curved sections the group was able alleviate the amount of physics problems associated with the curved sections Finally the group realized that all that is needed for the project to demonstrate all the attributes associated with a maglev was a straight track While a curved track could expand on the basic principles by offering more track length to allow for in depth speed calculations closer demonstration of acceleration and deceleration a straight track allows for all of the basic functionality required for the project to be a success Design procedure Track material Now that the design of the track was settled upon the construction of the track was the next order of operation The main issue was to find out what kind of material the track was to be constructed out of This material would have to be Sturdy Lightweight Cheap Unable to interfere with magnetic field Track material Wood The first material choice for the track material that the group decided upon was wood Wood is an obvious choice as it fits the criteria of what the group wanted for a track for the maglev vehicle The advantages and disadvantages of wood generally speaking are as follows 59 Advantages of wood Non conductive Easy to work with Sturdy Relatively cheap depending on the type of wood Disadvant
17. orientation The rough material and dimensions for solenoid creation is itemized below e 8 of ferrous metal tubing thick Inside Diameter e 30 AWG copper magnet wire approximately 1000 of length e Mounting brackets to vehicle or aluminum channel with cut outs Final Solenoid Design A few details changed with the final design of our solenoids Firstly instead of ferrous metal tubing for the cores an air core substitute was used The air core consisted of thick plastic tube and the sides of the windings were held together by aluminum sheet metal cut outs Instead of making cuts in the channel itself the solenoids fit snuggly on the inside and glued in place Ferrous metal could not be made for the cores due to the permanent attraction between the track magnets This would interfere with our braking functions and the desired forward and backwards movement 69 4 1 3 Car Design 4 1 3 1 Lego Design The initial design idea was to build the car using an assortment of Lego bricks and stud plates Seeing as Lego construction is extremely easy it would eliminate the need for power tools when designing the dimensions of the car Some of the Lego pieces that would be needed for this design path are listed as follows Dimensions 5 x 8 Lego stud plate foundation 4 4 x 1 stud Lego bricks 2 12 x 1 stud brick 4 4 x 8 stud brick 3 4 4 x 6 stud brick 1 x 10 stud brick With t
18. regulate the current into the Arduino According to the datasheet a max of 40mA DC current flows through the I O pins and since the linear Hall Effect sensors Vout functions at a quiescent voltage of 2 5V with an operating range of 2 5V 1k ohm resistors should be plenty to send variable current of 0 5mA to the board On the Arduino there is a 5V pin which sends a regulated 5V to the hall effect sensors which operate between 4 5V 5 5V This pin helped clarify the choice of the Arduino board over the MSP430 Figure 5 1 1 is the schematic for how the pin connections and the sensors will connect and interact 97 ARDUINO Figure 5 1 1 Connections between the A1301 sensors and Arduino Board 5 1 2 Interfacing SN754410 with the Arduino When interfacing the SN754410 H Bridge chip to the Arduino board it is important to organize which solenoid control pins on the IC is connected to which specific pair of Digital O s on the board This will be significant when coding its switching operation on the MCU One SN754410 has 16 pins of which 4 of those are utilized as ground or if heat is a factor will rather connect to a heat sink Also one IC will drive two solenoids applying current either left or right through the windings This requires 4 pins on the IC for each solenoid two for control and two for driving current Different colored LED s will be connected in opposing directions to signify which direction
19. see the signal changing in the pattern we want when we send it with the MCU then we know the signal is going to work We can connect the MCU to the H bridge to the solenoids and trust that changing the values using the MCU it will change the solenoid polarity correctly 6 3 6 Hall Effect Sensor through Solenoid functioning This is the final test before we put all pieces together for a finished prototype This step involves checking for the system to function correctly through each every step simultaneously The way this will work is by connecting all the pieces together in order to be ready to see the results We will pass the Hall Effect sensors over different spacing and polarities of magnets When we do this if everything is working properly we should see a proper change in the solenoid strength and polarity Following a similar model as the table 7 2 2 we will see the different distances and polarities cause different polarities of the solenoids Distance Orientation Expected Expected Expected Actual Correct cm polarity polarity polarity Polarity correlation solenoid solenoid solenoid 1 2 3 0 S 0 N 5 S 5 N 1 S 1 N Table 6 3 6 System function Test Table 110 If we are able to fill this table out and meet all of the expectations our design will be almost complete If this test results in a correct form it proves that the general function of the car is
20. sent correctly is by orienting the Hall Effect sensor at different distances from both an S and N polarized magnet and recording the value using an oscilloscope or multi meter Once we have created a table of expected values we will hook up the TI SN754410 to the Atmega328 Once it is ready we will implement the code for taking analog inputs and save it to the MCU and compare the values being stored in our variable to the expected value on our table The table below will be the one that we fill out in order to determine if we were successful in communication Distance cm Orientation Expected Received Correct output Value correlation 0 S 5 0 N 0 5 S 4 5 N 1 1 S 3 1 N 2 Table 6 3 3 Hall effect reading Test Table If we complete this table and have a successful reading on each section we will know we have completed our connection 108 6 3 4 Testing Solenoid polarity and H bridge function In order to test that our solenoids will be following the correct polarity arrangements we will test them in two parts We will first need to test whether or not the Solenoid is following the expected polarity when current is sent through Then we will hook up the solenoid to the TI SN754410 and determine if the binary controls to the H Bridge will control the solenoid in the proper fashion In order to test the polarity of the solenoids we will simply attach each end of the solenoid to a power supply c
21. solenoid as it passes through 67 Propulsion magnet Propulsion magnet Solenoid Figure 5 0 The side view cutout of the track featuring the propulsion magnets The field lines shown are the result of the halbach arrays on either side of the track Ideally the field lines are to be focused on the solenoid and should be minimized as to not interfere with the levitation array A design idea for the halbach array pertaining to the propulsion magnets was taken from the FTC Robotics team Antipodes The team used an alternating magnet spacer combination for the propulsion array that consisted of rectangular neodymium magnets separated by brass spacers Behind these brass spacers however were cylindrical magnets oriented in a halbach array This design is interesting as it provides a strong propulsion base with the permanent magnets and offers a reinforced magnetic field from the spacer array Magnets Field lines going towards the solenoid Figure 5 1 A mock representation of the Team Antipodes brass spacer configuration The cylindrical magnets are arranged in a halbach array to where the flux is directed towards the solenoid the center of the track 68 4 1 2 Solenoid Design The car will have three solenoids mounted on the bottom of the car utilizing mounting brackets that will fit a 1 4 inch to 1 2 inch tube preferably made of iron lron or steel tubing would be ideal because the ferrous metal will strengthen th
22. specifications will include the type of materials used in the construction of the track construction of the car type of permanent magnets that will be used any MCU s that will be used and their functions the type of propulsion system that we will use et cetera 2 3 1 Levitation For an in depth look at how we will achieve magnetic levitation we look to the Inductrack design To put it plainly the Inductrack design uses an array of permanent magnets to levitate the train This array of magnets is called a Halbach array The Halbach array is a special type of arrangement where the magnetic field is essentially focused on one side while the other side s magnetic field is virtually suppressed Figure 2 5 Halbach array fundamentals By orienting the magnets in such a way where the direction of the magnetic field is rotating spatially we can create a focused magnetic field Reprinted with permission from Wikimedia Commons license photo is public domain By creating a Halbach array to where the magnetic field is focused towards the under carriage of the vehicle the vehicle need only to be equipped with permanent magnets of the same polarity This way when placed on the track the magnetic fields repel each other causing levitation The Halbach array arrangement will need to extend for the length of the entire track to facilitate the levitation The Halbach array is ideal for creating levitation as it is essentia
23. to read the location specifically on the track and send it to the remote The communication between the analog remote controller and the systems controller occurs through an adjustable analog knob The control is made of Plexi glass for protection of its internal components This remote controller controls not only the acceleration of the vehicle but the braking system as well By making an analog remote they simplify the speeding and braking of their system by adjusting the knob for acceleration and returning the knob to its original stable position for braking Turning the knob in either direction puts the vehicle in motion in either direction as well Since our team is to use a remote controller for the system with digital inputs to the vehicle s micro controlling unit adjusting speed and braking would be a challenge that was definitely undertaking The other biggest difference aside from the choice of a remote controlling device is the track The Antipodes team built a horizontal track while our project s design involves a circular track This also will present diverse challenges since the team will encounter different situations in the turning of the vehicle where other similar projects and work was based of a linear track and no need for turning of the magnetic levitation vehicle was necessary 3 1 2 Small Scale Maglev Train Another design similar to the project at hand is a small scale version of a magnetic levitation train done by a se
24. vehicle we have designed and if it meets the requirements we set for ourselves 6 3 1 Initial Testing of Android Application Testing the Android smartphone is an interesting aspect and important part of this system This application would provide the entire user interface for the group to interact with the system When it comes to program and application testing the group is prepared to encounter many issues and bugs before it gets a working application Before and interfacing with the microcontroller can be done the application itself must work appropriately The main role of the Android application remote controller is to send and receive data to and from the microcontroller The medium through which this data was to be sent is Bluetooth Wireless Communication This is the smartphones first and most important role This is to establish a wireless connection with the microcontroller of the system and initiate communication Interfacing with the Bluetooth To begin testing the application after all Bluetooth features have been added to this application the group will begin checking to see if the Bluetooth will be able 105 to be enabled through the application Since the Bluetooth capabilities of the smartphone are a separate application than the application being designed and developed specifically for the group s magnetic levitation system it needs to be able to access this Bluetooth application and enable it directly through the designe
25. work and have already been tested by its manufacturer If the android smartphone application can successfully detect all of its surrounding Bluetooth enabled devices within the given range then this test will be successful Otherwise if the application is unable to detect any of its surrounding devices or only certain ones but not all of the Bluetooth devices then the test case is a fail If the device detects no devices then the test is definitely a fail If the device only detects a portion of the devices in range then the case is more specific That means that some part of the application is working correctly while there is still some error since all of the devices will be shown in a list view This case if encountered will be face uniquely although the group does not believe to come across this problem Once both of these test cases which are enabling the Bluetooth and discovering any external Bluetooth devices are met then the actual interfacing between the Android smartphone application and the Bluetooth Module can begin This brings 106 about a test case that is essential to the project as this is how the entire interfacing or commands will be exchanged by the user and the vehicle 6 3 2 Bluetooth communication to the Atmega328 The first part of our system is to receive a signal from a Bluetooth controller In order to make sure that the MCU is receiving the correct signal is very simple Once we have the connections between t
26. 2 A3 A4 pins 2 7 10 15 of the first device and A1 A2 pins 2 7 of the second TI SN754410 Once the pins are connected correctly we only need a simple amount of code to actually deliver a signal Since the H bridge circuit s input is hooked up to a digital output of the MCU all we need to do is switch the port value Before toggle function TI SN754410 TI SN754410 Figure 4 1 1 4a Switch signal block diagram Using something simple such as Digital_Toggle port which is a code that allows the easy switching of the digital output signal we can accomplish this task For example if the output port D1 on the Atmega328 is set at 0 we can simply run the code of Digital_Toggle D1 and we will see that the new value of that wire is 1 instead of 0 When the wire value switches we can see that it also switches value in the TI SN754410 This means that it switch the flow of current if the switches are organized correctly This change in current is what will be changing the polarity of solenoids and effectively moving our vehicle There are many different possibilities for switch organizations that we will have to be aware of in order to get our car to function properly As described early we would need the magnet to be oriented to NS if the magnet it just passed is N polarized We will need it to be SN if the magnet it just passed was S polarized If the magnet is aligned with either an S or N polarized magnet we will need the s
27. 4410 2 33 x 2 4 66 Winner 3 2 7 1 1 SN754410 Truth Table The truth table in Figure 3 2 7 1 1 highlights the states and functions of the Digital Inputs for the H Bridge IC s This is for one of the solenoids which can be translated for the other two just interchange 1A to 3A and 2A to 4A and 1 2 EN to 3 4 EN 1 2 EN 1A 2A Function 1 0 1 N S orientation 1 1 0 S N orientation 1 0 0 Turn off solenoid 1 1 1 Turn off solenoid 0 X X Turn off solenoid Figure 3 2 7 1 1 3 2 8 Hall effect Sensor Hall Effect sensors provide a voltage read out that is proportional to the strength and polarity of the magnetic field it is sensing In other words a Hall Effect sensor could read a standard 2 5V when no magnetic field is within range This value will fluctuate 2 5V depending on the polarity and proximity of the magnet being sensed For example when an S pole comes within range of the sensor the output voltage would fluctuate less than 2 5V how much less depends on the field strength When an N pole comes within range of the sensor the output voltage would become greater than 2 5V depending on the field strength Another important aspect to consider with Hall effect sensors is the strength of the magnets in which we are using For the track we will be using Neodymium magnets which are the strongest permanent magnets available for purchase by the public These magnets are capable of causing damage if han
28. A scan H Device 23RR45F6 PAIRED kad Figure 2 3 3 1 Main Menu When paired with the magnetic levitation vehicle or more specifically the microcontroller system that will control the vehicle the controlling interface will be displayed which will allow the user to send commands to the device The prototype for this Controlling interface can be seen in Figure 2 3 3 2 The top of this interface will display a menu button and a settings button The menu button will allow the user to return to the Main Menu interface or activity as it is called in the Android Software Development Kit The settings button will allow the user to access the application settings as the previous settings button allowed on the Main Menu activity Then the three main commanding buttons will be in the center of the screen These will send outputs read by the microcontroller to give our vehicle commands The two commands that will allow the user to put the vehicle in motion are forward and back which are pretty self explanatory The Stop button will allow the user to bring the vehicle to a stop when the device is in motion All of these commands will be handled by the microcontroller which will be pre 12 programmed to execute specifically on the vehicle depending on each specific command At the bottom of this interface will be displayed a meter that will show the vehicles speed as it moves about the track The speed will be displayed in mph miles per h
29. MagLev Group 2 12 6 2013 Julio Arias Sean Mawn William Schiller Leo Sell Table of Contents 1 0 Executive Summary 2 0 Project Description 2 1 Project Motivation and Goals 2 2 Objectives 2 3 Project Requirements and Specifications 2 3 1 Levitation 2 3 1 1 Vehicle 2 3 1 2 Track 2 3 2 Remote Control 2 3 3 Android Application Interface 3 0 Research Related to Project Definition 3 1 Bibliography of Related Work 3 1 1 Linear Motor for Maglev Train 1997 W Beaty 3 1 2 Antipodes Magnetic Levitation Vehicle 3 1 3 Small Scale Magnetic Levitation Train 3 2 Relevant Technologies 3 2 1 Microcontrollers 3 2 1 1 Atmega328P 3 2 1 2 RN 42 3 2 1 3 RN 52 3 2 2 Application Development 3 2 2 1 iPhone Development 3 2 2 2 Android Development 3 2 2 3 Android Smartphones 3 2 3 Wireless Communication 3 2 3 1 Wi Fi Communication 3 2 3 2 Bluetooth Communication 3 2 4 Electromagnets 3 2 5 Solenoid 3 2 6 H Bridge Circuit 3 2 7 H Bridge ICs 3 2 7 1 TI SN754410 3 2 7 1 1 SN754410 Truth Table 3 2 8 Hall Effect Sensors 3 2 8 1 Allegro A1301 Hall effect sensor IC 3 2 8 2 Optek OHO90U 3 2 8 3 Melexis US1881 3 3 Levitation 3 3 1 Static Magnets vs Electromagnets 3 3 2 Lifting Power calculations 3 4 Distance Tracking With Sensors 3 5 Three Phase Drive System _ O OONDOD FP oO 3 5 1 Approaching N Pole B magnet 3 5 2 Perpendicular to N Pole B magnet 3 5 3 Leaving N Pole B magnet 3 5 4 Test Case scenarios for the Drive
30. Magnetic Field Magnet Force On Vehiche From LSM Winding LSM End View j Vehicle etic eld f Magret eee Propulsion Force Is Y info Screen a Crossover Current lin LSM Winding Figure 3 3 2 1 Diagram displaying LSM propulsion Reprinted with permission from MAGLEV2000 com 47 3 4 Distance Tracking with Sensors One of our tasks will be calculating speed of the maglev vehicle and displaying on an android phone It will be important to understand how position on the track will be calculated The position can be measured from the readings given from the Hall Effect sensors As mentioned before the sensors act linearly between 0 and 5 Volts This will be taken into account when the sensor sends signals close to OV and 5V to the MCU When either value is read this means that the sensor has passed a N pole oriented magnet or an S pole oriented magnet Since these magnets will be spaced a specified distance apart a counter can be implemented that will increase with every passing magnet on the track This counter also has a specified distance associated with it For example when the car goes too one N pole magnet to the next S pole magnet it has traveled the length of one magnet and the spacer in between This distance will be roughly 1 inch If each of the two straight sections of the track is roughly 2 feet and the arcs are each 1 foot in diameter The distance traveled around the arc is related to the circumference 2 pi r
31. S polarized magnet If it has just passed an S polarized magnet the solenoid needs to be SN oriented If it has just passed by the OV marker it means that specific sensor has just passed through an N polarized magnet If it has just passed through an N polarized magnet it needs to be NS oriented Now if it is reading exactly 5 or exactly 0 that means it is directly aligned with either a magnet of either polarization When it is directly aligned with either polarized magnet the solenoid needs to be turned off Following this specific pattern will allow each magnet to move cohesively and separately allowing for smooth motion in the direction of our choice The way we accomplish the task of turning the analog input into a correctly oriented solenoid described above is the programming The small portion of code above is just an example of what the code will be doing The variables will be 77 similar but syntax and exact names and coding will differ once we grow closer to completing every goal The code is also based on just one of the analog input ports while the final code will be contain all the analog ports The code shows an if statement that will determine if the analog signal being received is exactly OV or exactly 5V if this is the case the switches will change to turn the solenoid off Based on our understanding of the H bridge circuit we will have to change switch 1 to 0 and switch 2 to 0 also With both of these being O it will caus
32. SPI_SS i a neg 20900 Resa es Bat 9 vaoaz2z23 z bbs rTITTITITI Oorannwrw oo SNNN N N NAN N Figure 3 2 1 3a RN 52 Pin Diagram 24 Pin Symbol 1 O Type Description Direction Default 1 GND Bidirectional with programmable strength Ground internal pull up down Bidirectional with This pin enters device firmware update Input Low programmable strength DFU mode at bootup if a USB device internal pull up down powers VBUS GPIO3 requires 47 kQ to 2 ground and 22 kQ to the USB VBUS GPIO3 signal if the USB VBUS is supplying power to the main board 3 Bidirectional with Reserved event register Toggles from Output High GPIO2 programmable strength high to low for 100 ms to indicate that internal pull up down the module s state has changed A microcontroller can enter command mode and poll 4 Bidirectional Analog programmable 1 O AIOO input output line 5 Bidirectional with Factory reset mode To reset the module Input Low GPIO4 programmable strength to the factory defaults GPIO4 should be internal pull up down high on power up and then toggle low high low high with a 1 second wait between the transitions 6 Bidirectional with I O High GPIO5 programmable strength Programmable 1 0 internal pull up down 7 Bidirectional with 1 0 High GPI012 programmable strength Programmable I O internal pull up down Pin Symbol 1 O Type Description Dire
33. System 4 0 Project Architecture and Software Design Details 4 1 Initial Design Architecture 4 1 1 Track design 4 1 1 1 Track Design Propulsion and Levitation 4 1 2 Solenoid Design 4 1 3 Car Design 4 1 3 1 Lego Design 4 1 3 2 Wood Design 4 1 4 Car Prototype Diagrams 4 1 4 1 First Car Prototype 4 1 4 2 Second Car Prototype 4 1 5 Car Materials 4 1 6 Building Plan for First Prototype 4 2 Microcontroller functions 4 2 1 Programming functions 4 2 1 1 Receiving order from Bluetooth 4 2 1 2 Taking the Hall Effect input 4 2 1 3 Microcontroller conversion function 4 2 1 4 Sending the Signal to the TI SN754410 4 2 1 5 Bidirectional vehicle 4 4 Android Application Development Architecture 4 4 1 Application Class Diagram 4 4 2 Application Programming Plan 4 5 Interfacing Microcontroller and Remote 4 5 1 General Communication through the System 4 5 2 Establishing a Connection 4 5 3 Client Server 4 5 4 Commands Exchanged 5 0 PCB Circuit design 5 1 Arduino Interfacing 5 1 1 Interfacing A1301 with the Arduino Board 5 1 2 Interfacing SN754410 with the Arduino 5 1 3 Interfacing Bluetooth with the Arduino 5 2 Arduino ProtoShield PCB surface 6 0 Project Prototype Testing 6 1 Hardware Testing Environment 6 2 Testing the Hall Effect Sensors 6 3 System Testing 6 3 1 Initial Testing of Android Application 50 51 51 55 104 107 6 3 2 Bluetooth communication to the Atmega328P 6 3 3 Testing Hall Effect Sensor to the Atmega328P 6 3 4 Testing S
34. The radius is half a foot therefore traveling one arc length is equivalent to Pi feet or 3 14592654 feet Track type quantity Length Straight Section 2 4ft Half circle 2 6 283185307 ft Total 10 283185307 ft One lap is equivalent of 10 28318 ft Since there are about 12 magnets in relation to 1 foot the amount of magnets passed would be around 124 in total Both sides of the propulsion gap have this amount of magnets so this equates to an estimate of 248 alternating polarity magnets For distance measuring purposes only half of that number will be used Figure 3 4 shows the distance between magnets and relative distance of the Hall Effect sensors on the vehicle The polarity of the magnets will alternate on the track for optimal drive The spacers between the magnets are utilized for optimal magnetic field lines and also to cut down on costs since N42 magnets are expensive in large quantities Now that the distance has been calculated it can be sent back to the android phone for speed calculations The app itself will have an internal timer which will be set and reset with each trial run Having a time measurement and distance reading speed can be calculated and converted to desired units of measure within the coding of the app 48 N Pole S Pole r magnet spacer oe Hall Effect Sensor 1in Figure 3 4 Interaction between sensors and track magnets 3 5 Three Phase Drive System The
35. William Schiller To info maglev2000 com Sent Tuesday July 09 2013 12 41 AM Subject Permission for image use To whom it may concern My name is William Schiller and I m an Electrical Engineering Student at the University of Central Florida I am sending this email to request permission to use your image displaying LSM propulsion for my senior design paper The image is located on http www maglev2000 com works how 03 d html Thanks William Product Photos SparkFun product photos may be used without permission for educational purposes research papers school projects ete However permission must be granted for commercial use and proper credit to SparkFun must be given For inquiries about the use of our product photos or permission to use them please contact marketing sparkfun com Legal LEGAL NOTICE Copyright 2013 Allegro MicroSystems LLC Allegro All Rights Reserved Permission is hereby given to copy any information contained herein provided it is clear on the copy that the information came from Allegro Allegro reserves the rightto make from time to time such departures from the detail specifications as may be required to permit improvements in the performance reliability or manufacturability of its products Allegro reserves the right to discontinue any product without notice Nothing contained herein shall be construed as conferring by implication estoppel or otherwise any license or right under any pat
36. accomplish all required tasks Memory The 1k bytes of EEPROM memory will be used to store constant values regarding the distances between magnets and other distances that are crucial to the design but also that might be changed as time goes on This will also be used to control the variable leading to connection with the Bluetooth device Since we will possibly want to switch cell phones at some points we would like to be able to slightly adjust this in the memory The Flash memory allowed by this microcontroller will allow us to save our program to the device It is large enough to sufficiently control all aspects expected of this project and possibly more as we move through 5V output At first this was an ignorable feature involved in this design Once our design move forward this feature gave our group and easy and efficient source that could power each of our sensors and other microchips Instead of using complicated wiring and taking up more space than needed the 5v output condenses those hassles into one simple port Analog inputs Our design requires Hall Effect Sensors to help us control the vehicles movement The Arduino Uno rev 3 comes with analog inputs that are perfect for this specific use Other models of microcontrollers did not come with these Our Hall Effect sensors will be utilized to their fullest potential with the standard analog input pins 20 Digital inputs Since we will need to send our H bridge switches sign
37. ad method This method is called to accept a connection request It blocks all other interaction and therefore is not called in the main thread To stop this call a method called close on the BluetoothServerSocket or BluetoothSocket from another thread can be called and the blocked call will immediately return public AcceptThread Use a temporary object that is later assigned to mmServerSocket because mmServerSocket is final BluetoothServerSocket tmp null try MY UUID is the app s UUID string also used by the client code tmp mBluetoothAdapter listenUsingRfcommWithServiceRecord NAME MY UUID catch IOException e mmServerSocket tmp Run method This method is the main function for the thread and runs to listen for a connection while doing some work when a connection is accepted public void run BluetoothSocket socket null Keep listening until exception occurs or a socket is returned while true try socket mmServerSocket accept catch IOException e break If a connection was accepted if socket null Do work to manage the connection in a separate thread manageConnectedSocket socket mmServerSocket close break ee ey Cancel method Cancels the listening socket and then closes the running thread public void cancel EEY 4 mmServerSocket close catch IOException e 92 4 5 Interfacing Microcontro
38. age gt E 3 E O 5 0 5 5 Supply Voltage V Figure 3 2 8 1 2 Graph of the Magnetic Sensitivity vs Supply Voltage for the A1301 Reprinted with permission from Allegro Microsystems Another important aspect of the A1301 is that the IC will function under high magnetic fields and not break Instead the output gets pushed into a nonlinear region The UA package has the desired pin orientation we will use and looks as follows Symbol Pin Number Function VCC 1 Connects supply voltage to IC GND 2 Ground VOUT 3 Analog output to MCU Figure 3 2 8 1 3 Pin connections of the Allegro A1301 3 2 8 2 Optek OHO90U The OHO90U is a threshold triggered Uni Polar Hall effect sensor with a digital output Within a certain magnetic field threshold the output is triggered to a logic 43 level 1 or 0 For the OHO9OU a logic level 0 indicates that the sensor is on or above a set B value and off when the logic level is 1 or below a minimum magnetic field value The 0 logic level is reached after a magnet s S pole attains a close enough proximity to the sensor The Schmitt trigger built into the IC means that there is a hysteresis gap between when the sensor triggers on and off therefore allowing an amount of magnetic field leniency on how far the magnet is from the sensor This sensor is called Uni Polar because it only operates within range of an S po
39. ages of wood e Weight e Cost depending on type of wood e Susceptibility to outside elements The advantages of wood towards this project are obvious The material is first and foremost non conductive Wood is also a sturdy material able to facilitate the high speed travel relative to this project The main problems faced with the debate of wood were the susceptibility to outside elements and the cost of wood The bulk of the finance in the project is geared towards the permanent magnets and as a result cuts must be made in other departments In order to construct a desirable track out of wood the group was forced to investigate the different types of wood that would be considered worthy of constructing a track from The types of wood considered by the group were Balsa Oak Pine Cedar Fir The type of wood that was to be used was a source of debate within the group Balsa wood is the lightest out of all of the considered woods however it is flimsy and weak For the track the group decided that balsa wood is not ideal and would not be able to handle construction let alone any of the propulsion forces Oak was the next choice for debate amongst the group The strengths of oak wood lie in its durability It is strong enough to support the weight of the magnets and the forces acting on it via the vehicle s motion However oak is heavy and somewhat expensive As it was decided that much of the funding that the group was going to have to
40. al was 0 signaling an N magnet The solenoid would switch to SN and it would hold itself in position If this process is completed correctly then the MCU will have an efficient braking system This code will be implemented for each of the solenoid Hall Effect sensor combinations If we have all three solenoid Hall Effect sensor combinations functioning the same it will end up being smooth effective motion Once we have the proper code to convert the analog signal to a digital output of the switches then we will be able to send the correct digital output to the H Bridge achieving movement With the correct timings and distancing established we will send the signal from the MCU to the solenoids in order to have created a successful project 4 2 1 4 Sending switch signals to SN754410 Once we have received the analog signal and converted into a digital assignment for the switches the final task of the Atmega328 is to send this signal to the TI 78 SN754410 If the correct signals are sent to the H Bridge then the solenoid will be in the correct orientation and therefore be applying the correct forces for movement This means that all we need to know is how to change the output of the specific digital port of the Atmega328 to the correct port of the TI SN754410 The ports used on the Atmega328 for the switches will be DO D1 D4 D5 D12 D13 pins 2 3 6 7 16 17 Those ports will be connecting respectively to the TI SN754410 ports of A1 A
41. als the multiple digital inputs will definitely be utilized We have to make sure our all of those are heading to the correct place Also the digital inputs will have to be used in order to connect the Microcontroller to the phone using the RN 42 to connect wirelessly This will use the rest of the inputs and outputs for the digital section of the MCU 3 2 1 2 RN 42 The RN 42 is a device used to connect through Bluetooth Since this device was so popular in t he hardware community it was an easy choice for the group We knew that with its popularity there will be a large amount of resources to learn how to use the device Also the popularity could hint toward the quality of the device being better than its competitors This device is programmed by simple ASCI command language Block Diagram CSR BlueCore 04 External Figure 3 2 1 2a RN 42 Block diagram NEEDS CITATION When we configure the RN 42 we will be able to the LAN default settings of e Baud rate 115 200 e 8 bits e No Parity e 1 stop bit e Hardware flow control enabled We will need to follow the configuration settings in order to establish a connection between the device 21 a sind DESCRIPTION a confie LOCAL onl a _Contiuous config REMOTE onl Table 3 2 1 2a Configuration Gales Along with the configuration timers we will need the PIO and DIP switches configuration Ta mm a or Cadi N ARID OFF disabled ON enable Bwige 07 OFF s
42. am designed for companies wanting to interface their technologies or devices with Apple s products and was not what a senior design group was looking for Furthermore in order to access the iPhones Bluetooth capabilities from the application the external device or peripheral had to support Bluetooth 4 0 Low Energy LE devices This would limit our choice of a microcontroller and force us to choose one that might not be the best fit for our system Using the iPhone as a remote controller meant we needed to buy kits that were specific to iPhone interaction and therefore more expensive When it came down to testing that is where the team believed had the upper hand since we had an iPhone 5 one of Apple s latest developments In order to test our application there was an emulator that simulated the iPhone environment and had most of the capabilities that an actual iPhone would have For the 27 magnetic levitation system we needed the actual smartphone as the remote controller for the vehicle not a simulated one which was fine for initial testing purposes Testing our application on our iPhone brought another issue with Apple For a developer to test their application using Xcode you had to become part of Apple s developer program which cost 99 for a year Although this was a cost that could be overcome and might be worth its value the fee was still a cost that would be factored in our budget After all of these obstacles were conside
43. application is interested in is the permissions part of the manifest file since it will be accessing an external library and needs to interact with the smartphone s built in Bluetooth application The permission is declared in the manifest file as follows lt manifest gt lt uses permission android name android permission BLUETOOTH gt lt manifest gt 86 4 4 1 Application Class Diagram Figure 4 4 1 shows the class diagram for the overall application The method used for the diagram is considering that the application will be developed using a standard version ver 4 3 of the Eclipse Integrated development environment with the Android development tools plugin Each class and or activity shows the objects and functions that are essential to its specific purpose Class Diagram Maglev Controller Main Class BtAdapter BluetoothAdapter Devices Set mReceiver BroadcastReceiver filter IntentFilter Controller Class onReceive Context Intent foward int back int 4 stop int distance int 0 1 moveFoward moveBack stopVehicle ConnectThread Class getDistance int displaySpeed int int Socket BluetoothSocket InStream InputStream OutStream OutputStream ConnectThread BluetoothSocket run write Byte cancel Figure 4 4 1 4 4 2 Application Programming Plan Main Class The Main class is where the connection will be established betwee
44. arranged in a Halbach array to achieve levitation while the EMS system uses electromagnets controlled via a feedback loop Regardless of what we chose it would have to be small scale For static magnets our choice was the neodymium NdFeB permanent magnet These magnets are the strongest permanent magnet manufactured Neodymium magnets are used in a wide array of applications ranging from hard drives fasteners and motors Input Output Grade N42 v Pull Force Case 1 Pull Force Case 2 Pull Force Case 3 Magnet to a Steel Plate Between 2 Steel Plates Magnet to Magnet Length 1 in x sE n i 7 7 34 b 21 24 b 7 34 b Width 25 sj in Force vs Distance Force vs Distance Force vs Distance Thickness 125 Slin e at a 15 E 15 e e a 8 1 81 8 10 Distance 0 7 in x 5 4 5 ns c Ww uw TO Calculate 5 ue K distance in distance in distance in Click for larger chart Click for larger chart Click for larger chart Figure 3 1 Magnetic Force vs Distance chart on a permanent neodymium magnet of grade N42 Shown are 3 scenarios detailing the pull force of a permanent magnet 1 x 25 x 125 Reprinted with permission from K amp J Magnetics INC For electromagnets we would use a simple electromagnet structure that would consist of tightly wound coils around a core preferably ferrous There are problems that arise with creating the necessary lift without interfe
45. ata to the remotedevic public void write byte bytes try mmOutStream write bytes catch IOException e Cancel method Is used to end the connection between the paired devices This method can be called from the main class or thread when device pairing is done Called from the main activity to shutdown the connection public void cancel try mmSocket close catch IOException e 90 As mentioned one of the devices must act as a server and the other as the client in order for one to open the connection and the other device to make the connection Figure 4 4 1 1 shows the ConnectThread Class and the AcceptThread class in the Client Server model system The AcceptThread class serves as the server which opens the server socket and the ConnectThread class behaves as the client who attempts to make the connection Class Diagram continued AcceptThread Class serverSocket BluetoothServerSocket Gaul SERVER AcceptThread run cancel 0 1 ConnectThread Class Socket BluetoothSocket InStream InputStream OutStream OutputStream C LI E N T ConnectThread BluetoothSocket run write Byte cancel Figure 4 4 1 1 Server and Client Class Diagram AcceptThread Class The purpose of this class is to hold open the server socket and listen in for connection requests from the client 91 serverSocket Opens the connection for the server AcceptThre
46. ay This technology is in use overseas albeit most of the breakthroughs that are related to maglev are strictly experimental Commercial maglev rails are few and far between as there are only 2 rails in existence today that transport people Our maglev rail will feature a modified version of the Inductrack maglev design as well as Electromagnetic Suspension design ideas The vehicle will feature a 3 phase linear motor mounted on the underside The vehicle will also be equipped with permanent magnets that will react with the track to create levitation For levitation the track will be outfitted with two rows of permanent magnets arranged in a Halbach array This arrangement will direct the magnetic field towards the underside of the vehicle The on board permanent magnets will react with the track as stated above and will result in levitation This track will be a circular track to demonstrate the speed capabilities of maglev technology While our vehicle will have the ability to go forward and backward with a circular track we can apply fully power to the vehicle to demonstrate an important feature of maglev technology high speed The vehicle will be controlled via a mobile device The mobile device will interface with a Bluetooth module on the vehicle and will be able to be controlled wirelessly from the device The cost of the project is estimated to be in the range of 600 900 US dollars In order for this project to be a success the v
47. ays clean the surface of the side of the magnet with Isopropyl alcohol The oils from fingerprints can be enough to lessen the bond to the gluing surface e Scratching the surface of the magnet to enhance the bond Do this with sandpaper or a sharp object such as a nail 73 e Many strong adhesives will work but what works best is Two part Epoxy When buying Two part epoxy there is a variety of drying times between 5 and 30 minutes The quicker the drying times the better although the price seems to reflect this time reduction e It is important not to use a glue gun the high temperatures can demagnetize the magnets Once the main body is finished it is important to now focus on the design of the aluminum channel This channel will hold the three solenoids circuit wiring and the Hall Effect sensors for position sensing The channel will be between 1 and 2 wide and run the length of the board about 7 Cut three circular holes through both sides of the aluminum channel to house the solenoid tubing cores Cut big enough to fit to size of the solenoid tubing if oversized it should not be a problem if two rubber washers are placed on both ends of the solenoid pipe Double check the spacing of these holes they should be far enough apart so that the sensors can be correctly placed in between to detect the magnet polarity and position Next the ferrous pipe must be cut into three sections for each of the respective solenoids These s
48. be located on four extended corners of our car The four magnets would roughly be rectangular 1 long and wide this will fit ideally glued to the underside of the 1 5 inch appendages from the main body The simplified breakdown of the material dimensions is as follows Dimensions 2 7 x 2 pine wood blocks 7 x 4 pine wood block 4 x 3 Circuit board housing 4 1 x 2 N42 NdFeB rectangular magnets 1 5 4 1 5 7 Arduino Board housing magnets glued to underside 5 Figure 4 1 4 1 Top view of 1 car Prototype 4 1 4 2 Second Car Prototype The second prototype for our car used only one wood cross section instead of two like in the 1 prototype Having only one section across the middle will affect levitation stability in a negative manner To counteract this negative stability affect we will have to purchase larger magnets and orient them lengthwise across the middle piece The team thinks that ultimately this design will not be the best candidate because it will cause the car to rock dip in the front and back when significant acceleration forces are applied when braking at specified 71 distances The simplified breakdown of the material dimensions for the second design is as follows Dimensions 7 x 4 pine wood blocks 7 x 4 pine wood block 4 x 3 Circuit board housing 2 x 1 N42 NdFeB rectangula
49. ce can be All three major types of maglev technology revolve around the inner workings of the track and the train Since the need for mechanical parts for propulsion have been virtually wiped out the only things that would require maintenance regularly are the track magnets and the train magnets As far as goals are concerned the main goal of this project is to demonstrate the capabilities of maglev technology By creating a small scale project of a maglev train we can demonstrate in person how this kind of technology works and what its capable of In terms of personal goals for the project performance the main goal is to achieve levitation and propulsion via magnetic fields without the need for a manual start In order to demonstrate the technology in full our train car 5 vehicle or apparatus must first achieve levitation Levitation is key as it will demonstrate the absence of contact between the vehicle and the track This will eliminate friction between the track and vehicle and allow for frictionless linear motion The next step is to achieve linear motion via magnetic fields By manipulating either a linear motor mounted on the car or manipulating electromagnets in the track we can achieve a push pull effect based on the polarity of the magnets 2 2 Objectives The objectives of the project are as follows e To achieve levitation through a magnetic field generated by permanent magnets located on the track e To achieve
50. ch is Bluetooth 4 0 Low Energy Which means the group will be getting the best out of the phone Samsung Galaxy Note 2 The Samsung Galaxy Note brings for the about the biggest user interfacing screen out of all three smartphones in comparison with an almost six inch display It also has a 1 6 GHz quad core processor for speed and usability Looking at its Bluetooth capabilities the Note 2 also comes with Bluetooth 4 0 Low Energy In essence the only significant difference with the other phones was its screen size Samsung Galaxy S4 The Galaxy S4 is the latest in Samsung s smartphone technology It has a 5 38 inch screen significantly bigger than the HTC One but at the same time much smaller than the Galaxy Note 2 also carrying a quad core processor but a bit faster that the HTC One and the Galaxy Note 2 The processor speed is 1 9 GHz outrunning the HTC One by 200 Hertz and the Galaxy Note 2 by only 300 Hertz When it comes to Bluetooth Technology the Galaxy S4 also carries the latest Bluetooth 4 0 Low Energy technology In essence there was no major difference between these three phones as seen for prospective remote controllers for the group s magnetic levitation system The essential features and specifications brought were equally capable to carry out the task for which the group intended the remote controller to do So deciding on which smartphone to choose for the team s remote controller was basically based more on individual o
51. come up with would be put towards the magnets the track material would have to be cheap and thus oak was not chosen as the track material The group next decided to investigate pine cedar and fir wood While these materials were ideal in terms of constructing a stable and sturdy track their expense was more than what the group would have hoped for 60 Track Material Acrylic Polycarbonate Wood proved itself to be reliable and sturdy the drawbacks relating to the on average cost of wood and the techniques used to shape and fabricate the appropriate track would seem time consuming Thus the group s next material to consider was acrylic and polycarbonate These materials interested the group for their advantages including e Non conductivity e Lightweight e Durable e Weatherproof Acrylic and polycarbonate are ideal materials for creating a track They are non conductive so they will not interfere with the magnetic fields produced by the magnets They are lightweight which helps with transportation and ease of use Acrylic and polycarbonate are notorious for their durability They are so durable that certain types are used in bullet shielding This project is not in serious demand of a heavy duty acrylic polymer but a sturdy lightweight track is what is desired Finally an added bonus that acrylic brings to the table is that it is essentially weather proof On its own it does not fall subject to the elements unlike wood Wo
52. connections Wi Fi has had the main purpose of connecting devices to the internet Since the smartphone has Wi Fi capabilities this would be a prospective connection to use to communicate with the vehicle s microcontroller Using Wi Fi would limit the connectivity to the Wi Fi connection strength and signal depending on the testing environment in which the system is not only tested but presented as well Although Wi Fi allows for longer ranges of interfacing between systems or devices ranges such as 300 feet from the networking node this is not really a pro with this particular system The user in this system will not be any farther from this system than a probable 10 feet making this Wi Fi advantage over Bluetooth a light one Wi Fi connectivity can be seen as more secure network with numerous securities Yet again for this system this is not a heavy advantage since the system s focus is not on security but communication and interfacing between a remote controller and a wireless enabled micro controlling hardware 32 3 2 3 2 Bluetooth Connectivity Communication between our smartphone controller and our magnetic levitation vehicle system will happen through a wireless Bluetooth connection between the smartphone and the microcontroller Bluetooth is a low power wireless and automatic radio frequency standard It will allow our smartphone to use as little power needed to send commands to our microcontroller Our Bluetooth connection be
53. ct is based on the latest version of each software program for best results As our project intends to be designed based on the latest generation s technology present the group will be using the latest available 112 software Each of these tools are essential to the building of the group s interfaces testing of the system and simulating the circuits and parameters designed for the system Software Summary Name Version Eclipse IDE 4 3 ADT Plugin Tools 20 0 0 Eagle Simulation Software 6 4 0 Ni Multisim Circuit Design 11 0 Arduino Development Environment 1 0 5 Android simulator 4 2 2 Table 6 4 6 5 Conclusion Maglev technology has the potential to create a new system of mass transit that is fast efficient safe and clean This project is aimed towards those who are not familiar with the technology and those who are not convinced and feel that this kind of technology is not an improvement over the current rail technology in use today 7 0 Administrative Content 7 1 Milestone Summer 2013 7 9 Submit forty page draft 6 3 Decided on Maglev project 6 10 Research on relative projects on how they achieved propulsion 6 17 Decide what systems group mates will focus on writing 6 24 Individual research and writing on designated subjects 7 2 Submit Table of Contents to Dr Richie 7 11 Group meeting with Dr Richie 7 31 Each group member has their respective 30 pages done and now formatti
54. ction Default 8 Bidirectional with I O High GP1013 programmable strength Programmable I O internal pull up down 9 Bidirectional with 1 0 High GPIO11 programmable strength Programmable I O internal pull up down 10 Bidirectional with I O High GPIO10 programmable strength Programmable I O internal pull up down 11 Bidirectional with When you drive this signal low the 1 O High GPIO9 programmable strength module s UART goes into command internal pull up down mode If this signal floats high the UART is in data mode Reserved Not available for use at runtime 12 Bidirectional USB data minus 1 O USBD 13 Bidirectional USB data plus with selectable internal I O USBD 1 5 Kohm pull up resistor 14 CMOS output tri state Output UART_RT with weak internal pull up UART request to send active low S 15 CMOS input with weak Input UART_CT internal pull down UART clear to send active low S 16 CMOS output tri state Output UART_TX with weak internal pull up UART data output 17 CMOS input with weak Input UART_RX internal pull down UART data input 18 GND Ground Ground Table 3 2 1 3b RN 52 Pin table 25 Using the Pin Diagram above we will be able to setup our hardware efficiently Comparison Since we have two options we have to figure out which one serves us better Using the research our group has found we can understand that both will be able to successfully complete the task of connecting our vehicle to the Bluet
55. d application This case can be tested by initializing the application attempting to enable Bluetooth then closing the application and checking the external Bluetooth indicator to see if Bluetooth was successfully enabled If it was enabled then the test case passes otherwise if the Bluetooth was not enabled then troubleshooting has to be done and the code needs to be changed Discovering other external Bluetooth Devices After testing and succeeding at enabling the Bluetooth on the smartphone through the application another test case has to be met before the microcontroller comes into play Since the android smartphone will communicate with the microcontroller wirelessly through Bluetooth it must be able to scan its surrounding range or environment and detect all of the Bluetooth devices present within a given range of about 30 feet This test case can be done by enabling the Bluetooth on the smartphone and then attempting to scan its surroundings for other Bluetooth devices Devices with which it can be tested are Bluetooth enabled laptop Another Bluetooth enabled smartphone Bluetooth enabled stereo Bluetooth enabled headset Bluetooth enabled MP3 Player Bluetooth Enabled Television These are just some devices for which the application s scanning and detection can be tested These are all prospective testing devices because the group is aware that these are standard devices that not only have Bluetooth but its Bluetooth capabilities
56. d be too risky to commit the entire track to a substitute that shared the as many advantages with it would be something to consider With that the group decided to investigate fiberboard and its advantages and disadvantages Advantages e Like wood non conductive e Inexpensive e Lighter than ordinary wood Disadvantages e Less sturdy than ordinary wood e Susceptible to elements The advantages of wood are improved upon with fiberboard in the areas of cost and weight Fiberboard is extremely inexpensive much less expensive than ordinary wood This offers the opportunity to let our budget breathe when it comes to the track materials It shares non conductivity with wood as well which makes it an ideal choice for the track Finally fiberboard is much lighter than wood While acrylic is lighter than both fiberboard and ordinary wood transporting fiberboard would be easy The disadvantages of fiberboard while apparent are few Structurally fiberboard is less sound than ordinary wood due to it being a composite of wood particles Its less dense and cannot handle the same type of stress that wood can That being said the type of stress that will be subjected on the track is not nearly severe enough to cause significant structural damage With all of the materials investigated and taken into consideration it was decided that the track was to be constructed out of a combination of fiberboard and acrylic These two materials were determine
57. d to be the best choices for a track based on reliability and cost effectiveness 4 1 2 Track Design Propulsion and Levitation The main purpose of the track is to facilitate a propulsion and levitation component that works in unison with the vehicle The static propulsion and levitation components will be constructed out of permanent neodymium iron boron magnets NeFeB The neodymium magnets will be arranged in a Halbach array to provide an adequate magnetic field that the vehicle will be able to take advantage of and thus lift and propel itself along the track 62 Grade N42 Length lin Width 0 25in Thickness 0 125in Figure 4 5 Magnetic field of a rectangular magnet 1 x 25 x 125 of grade N42 Reprinted with permission from K amp J Magnetics INC Levitation Halbach array theory To achieve adequate levitation a Halbach array is designed to create a localized magnetic field where most of its strength is concentrated in one direction The group chose a Halbach array as it has demonstrated its usefulness in achieving a desired magnetic field The advantages of a Halbach array e Minimizing friction and drag e Low magnetic field for commercial sized trains this is ideal as passengers would not be exposed to high magnetic fields To certain individuals high magnetic fields can be lethal e Reduced power consumption 63 Grade N42 x Pull Force Case 4 Magnet Repels Magnet
58. dled improperly Since our car will not be exceedingly heavy 2 pounds 3 at most the lowest grade Neodymium magnet N24 will suit adequately for our purposes Since grade N24 magnets are not readily available we will find the cheapest obtainable grade possible All Neodymium magnets have magnetic field strengths of around 1 Tesla 1T being the lowest grade N24 and 1 43T being the highest grade N52 Knowing the strength of the magnet is important because some Hall effect sensors have a maximum Field rating that when 41 exceeded could damage the sensor Below are a few Hall Effect sensors that will be considered for position sensing in our project 3 2 8 1 Allegro A1301 Hall effect sensor IC The following technical information is obtained from an Allegro Microsystems datasheet The A1301 from Allegro Microsystems is a linear 3 pin surface mount continuous time Hall effect sensor When considering this sensor one of the most important specifications to look at is the field sensitivity this IC s sensitivity rating is 2 5mV G What this means is that when our vehicle approaches a magnet in our track array the sensor will output a higher voltage depending on its proximity Highest voltage output occurs when the sensor is directly next to the magnet When looking at these readings we want the highest voltage rating per gauss in order to better interpret our graphical results and have higher accuracy with measurements Figure 3 2 8 1 s
59. e magnetic field the solenoids will produce If not there are other options for small diameter tubing such as copper and brass that could be ordered in a vast quantity of sizes from onlinemetals com For the purposes of this project each solenoid won t exceed 2 inches in length so buying tubing of around 6 8 inches will provide enough tubing to cut and make the cores of our solenoids If mounting brackets are hard to come by with the right fitting for the tubing purchasing a channel could be another plan In this channel tubing holes can be cut out to insert each of our solenoids The channels material should not interfere with the cars magnets or the tracks so aluminum would be ideal Two factors are important when creating the solenoids the number of turns and the current driving through them Since the current flowing through each solenoid will be 1 amp or less the solenoids must be wound a great deal Utilizing a small gauge of wire around 30 gauge and providing a substantial number of turns to cover the surface of the core multiple times the solenoids can be built of substantial field strength to interact with the track magnets Winding hundreds of feet of copper wire would take an incredible amount of time so using the help of a drill would save the team valuable time in construction It is very important that the turns of the solenoid be exceptionally tight otherwise the magnetic fields produced will not be of the desired intensity
60. e properties governing the electromagnets are the magnetic field B and the magnetic force H since the magnetic force deals with the lifting power of the magnets that will be left to discussion in a later section The two variables are interrelated with the permeability of the surrounding medium For free space the relation looks as follows B po Both the force and magnetic field are circulatory around the copper wire Using the right hand rule for magnetism the direction of the magnetic field can be deduced from the conventional direction of the current flowing through the wire Electron flow is different than the flow of electrons Reversing the direction of the current will result in a change of direction in the magnetic field This concept understanding will be ideal when designing the circuitry for magnetic field polarity detection and reversing the current when needed To amplify the magnetic field intensity we need our conducting wire to be tightly spaced as shown in Figure 3 2 4 below in Microsoft Paint The magnetic field lines are shown wrapped around the conducting wire 2 Figure 3 2 4 Magnetic Field intensity resulting from close placement of conductors The intensity is nearly doubled when conductors with the same current flowing through them are placed in close proximity of each other 35 3 2 5 Solenoids The electromagnet configuration for our project will consist of three solenoids with three Hall Effect sensors placed
61. e the circuit to put no current through the solenoid effectively turning it off Another possibility is that the Hall Effect and solenoid has just passed 5V South polarized magnet this means it needs to be SN The S side of the solenoid will push away from the S magnet behind it and attract itself to the N magnet in front of it The way the solenoid is changed from off to SN is by changing the switches in the H bridge circuit The SWO will be changed to 1 and the SW1 will to 0 Once it gets to the N magnet the Hall Effect sensor will read 0 and the MCU will use this information to determine it just passed the N magnet After it is turned off briefly it will switch to NS The N solenoid side will push away from the N and attract itself to the S magnet coming up The way it switches to NS is by changing the SWO to 0 and the SW1 to 0 The last possibility is if the MCU is receiving a brake command from the Bluetooth controller This means that it will no longer be following the pattern for movement described above because we do not want any movement The way our group has decided to handle this situation is by setting the value of switches and leaving them unchanged This will effectively stop the Maglev vehicle by attracting itself to one spot of the track This means that if the Hall Effect sensor is producing a 5 signaling an S magnet the solenoid will be set to NS This will pull the car to that point and stop The same goes for if the sign
62. eans we need to have a Mac laptop or have access to one None of our team members owned a Mac laptop to begin with After this issue can be overcome there is the next obstacle of becoming familiar with Xcode and the coding language used for development The main coding language used in Xcode is Objective C another technology our team was unfamiliar with Although Xcode does allow integration using other languages such as C or Java languages that the team was familiar and had previous experience with this would surely bring about issues when it came down to integrating the source code since these were not Xcode s native language To reiterate the team first needed a Mac laptop to run our Xcode IDE then there was the issue of learning and troubleshooting with a whole new language called Objective C After further research the team found that Apple disproved of using their devices such as the iPhone to interact with other peripherals that were not made by Apple This meant that there were very little sources to help us with our application since our remote controller would be interacting with an external microcontroller not made by Apple Unless one became part of Apple s MFi licensing program which allows access to the hardware components tools documentation technical support and certification logos needed to create AirPlay audio accessories and electronic accessories that connect to iPod iPhone and iPad This was an expensive progr
63. earlier our group has decided to test each part separately to guarantee that each part is working We have separated each part to its most basic function and decided we would test there The first test would be to assure that our Bluetooth controller is successfully communicating with the MCU Then we can test that our solenoid magnets are creating the correct pull and push We then will make sure that the MCU is receiving accurate information from the Hall Effect sensors Once we know the MCU is receiving the correct inputs we can also test that it s sending the correct outputs Also once we know the MCU is receiving the correct signal from the Hall Effect sensor we can determine if the code is functioning properly and that it s trying to turn the correct switches based on its analog input Before we put everything together we will make sure that all of the wiring is hooked up correctly from the Atmega328 to the TI SN754410 to the solenoids If that is functioning correctly we can test the whole system from the Hall Effect sensor to the Solenoids If those systems are working we will clear each system part to move onto the final project We will connect all different pieces and wire them together Once the maglev vehicle is built and connect to the Bluetooth controller wirelessly we will have a final prototype Once the final prototype is built we will be able to test it extensively to determine if we have succeeded in building the maglev
64. ect The group allocated 40 00 to the MCU and the Protoshield The Bluetooth module needed for the project allows for wireless communication from the mobile device to the vehicle The group allocated 16 00 for a Bluetooth module The power source comes in the form of a 9V rechargeable battery along with a recharger pack which the group allocated 10 00 for The EM detection was facilitated through the use of Hall Effect sensors which the group allocated 5 00 towards The rest of the budget allocation was put towards prototyping breadboards capacitors resistors and an H driver Overall the allocation for these items 20 00 In summary MCU Arduino Uno and Arduino Protoshield 40 00 Wireless Connectivity Bluetooth module 16 00 Power source 116 EM detection Hall Effect sensors 5 00 Prototyping and other items 20 00 9V rechargeable battery 5 00 Recharger pack 5 00 Financing for this portion of the project will follow suit along with the other portions of the budget where the group members will finance all the parts themselves The group developed a list of distributors for the parts of the miscellaneous section Lowes Home Depot Radio Shack eBay TI Texas Instruments 7 2 4 Financial Diagram The table below details the financing of the entire project All of the components were documented and their price was recorded and added for a total sum of the project cost
65. ed for the Android Operating System previously which was an advantage to choosing an Android device yet there was an iPhone testing device that would be available to test with our system making our decision in need of in depth research into each field of smartphone application development Before the decision of device was made we also needed to know how we were to integrate the smartphone as a controller for our system and communicate as a peripheral with our magnetic levitation vehicle on the magnetic track In order to send inputs and outputs or commands from our smartphone we needed a method or channel through which communication execution of these commands were to take place There was the option of using Wi Fi versus Bluetooth as a means to communicate between the controller our smartphone and the controlling system of our vehicle the microcontroller 26 3 2 2 1 IPhone Development Our first initial inclination was to use the iPhone as the remote controller to our system After plenty of research we found many obstacles in developing the application in the iPhone Operating System When looking into iPhone application development one must have the right tools to even begin The only suitable Integrated Development Environment IDE for Apple the company behind the iPhone to be used if one wanted to become a developer for the iPhone Operating System is called Xcode Now this software can only be run in the Mac Operating System which m
66. ed through the thickness of the magnet Now that the both the vehicle s flux and the track s flux are directed towards each other and the magnets in use are of the same polarity both objects will repel each other This repulsion creates the levitation needed for the vehicle to work successfully The picture below details roughly how the magnets would be oriented on the vehicle and on the track 66 Vehicle magnet Levitation magnet i Solenoid Figure 4 9 The cutout view of a prototype track design detailing the levitation magnets and the vehicle permanent magnets The arrows dictate the direction of the flux The repulsion from the like poled magnets would create a strong enough levitation to keep the vehicle situated above the track Propulsion Halbach array theory The same theory that went into developing the levitation array went into the propulsion array as well The threat of interference from magnets used in the sides of the track was too large to not employ a Halbach array A halbach array for the propulsion proved to be a little more challenging than the array for the levitation The propulsion is oriented towards the center of the track This means that the array must be rotated so that the magnetic field is pointing towards the slot that the linear motor sits in However this array is identical to the array on the opposite side of the track The magnetic field lines from both arrays will cross over the
67. ehicle must demonstrate all capabilities of maglev technology which include Levitation achieved via magnetic fields Propulsion achieved via magnetic fields Controlled via mobile device Adequately demonstrate the fundamental features of maglev technology high speed frictionless and clean Maglev rail technology has virtually limitless potential It can effectively change the entire infrastructure of mass land transit to something more efficient and environmentally friendly By moving towards maglev technology our railways can improve upon transit time maintenance costs and emission output Not only will maglev technology improve mass transit but other transit systems such as military and freight have much to gain from maglev rail technology 2 0 Project Description This project is an attempt to replicate the maglev transportation system that has been researched since the 1950 s with the advent of the first working full size linear induction motor developed by Dr Eric Laithwaite The idea of a transportation system relying solely on magnetic fields has been theorized since before the creation of the linear motor however only recently has the world seen actual maglev transportation systems for commercial use The systems currently in use are located in Shanghai China and Aishi Japan The system in use in Shanghai is the Transrapid system The Transrapid is a German designed maglev system and the system in use in Aishi is t
68. en appear on the device and can be tested Running the application on a real device provides better debugging benefits than on the emulator provided by the Development Tools since the real device is what will eventually permanently host the application Android development provides many advantages to the developer and encourages coders to use their tools by providing numerous source code 29 examples for a variety of different projects Table 5 shows the main differences that compelled the decision between which application development technology to choose In the end the team believed developing the controlling application was better benefitted by using the Android Operating System on an Android powered smartphone Since the purpose of the application is to interface through Bluetooth the Android development was the best option These specifications shown in the Table 5 list the most important and pertinent areas of interest that were considered for the purposes of this specific project These are the areas that would have the greatest impact on the magnetic levitation system that is to be designed and created for this project Only the two most prominent and well known technologies Android and Apple in this area of application development were considered due to both having the ability to accomplish the task Android vs iPhone Development Table Android Apple iPhone Tools Any Laptop any OS Only Mac
69. ent trademark or copyright of Allegro or any third party Allegro makes no representation that the interconnection of circuits or products described will not infringe on existing patent rights of Allegro or any third party Allegro does not warrant the accuracy or completeness of the information text graphics links or other items contained within these materials Allegro may make changes to materials or to the products described therein at any time without notice Allegro makes no commitment to update this information All products described herein are sold by Allegro subjectto Allegro s Standard Terms and Conditions which among other things limits Allegro s liability to repairing or replacing any defective product and disclaims Allegro s liability for direct damages incidental damages indirect damages consequential damages punitive damages and loss of profits Allegro s products are not to be used in life support devices or systems if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system or to affect the safety or effectiveness of that device or system General Enquiries Name William Schiller Contact No Email Id __wschiller knights_ucf edv To whom it may concern My name is William Schiller and I m an Electrical Engineering Student at the Message University of Central Florida I am sending this email to request permission to use your ima
70. epending on the type of propulsion used will determine the structure of the track In terms of levitation the track will be lined with two separate permanent magnet tracks arranged in a Halbach array These Halbach arrays will direct the magnetic field towards the underside of the vehicle The vehicle will then repel itself against the track creating the necessary levitation 2 3 2 Remote Controller The remote controller will be the main interfacing device between the users that being any of the members of the group or another adequate person and the entire system consisting of the magnetic levitation vehicle and the magnetic track The remote controller will send wireless signals to the microcontroller to initiate the movement of our vehicle The remote controller will need to send several commands to the vehicle which will control the entire movement of the magnetic levitation vehicle The main or general commands that will be sent are e Forward motion e Backward motion e Stop The system will not function by physical human interaction with the vehicle about the track as has been previously done by other senior design groups with a similar project The vehicle will receive signals from the microcontroller which will inform the vehicle to begin movement in either a forward or backwards direction The microcontroller will be wirelessly controlled by the remote controller This remote controller has to have the capability of wirelessly interac
71. er as well as the type of commands the smartphone will be sending Not only are there general examples of using similar functionalities that will be needed from our Android smartphone but there are also specific examples for interfacing with the specific Atmel Atmega Arduino uno microcontroller we will be using in our system This provides us with ample sources that will save time when troubleshooting and debugging our application Testing Again to test our application the group needs to know that all the functionalities work on a real device This is where the challenge was since the team did not have an android device When comparing to iPhone development the team needed a cost of 99 to test the application So analyzing the advantages of the Android development thus far makes it worth acquiring an Android smartphone or investing in one When a device can be acquired the team was able to test the application on a real device In order to do this USB debugging needs to be enabled on the device This can be done on Android 4 2 versions and newer by going to Settings About phone Build number tap seven times Developer options hidden by default When you return to the previous screen the Developer options can then be seen After plugging the device on the computer used for development the Operating System on the computer will install the necessary drives for the smartphone When the application is built and run the application will th
72. es in the display For the main interface the group will design a main menu that will have three main buttons and an additional help button A prototype of the main user interface can be seen in Figure 2 3 3 1 The first button Scan will be used to scan for devices with Bluetooth integration It will display a list view of all devices in range and viewable by our application Each device shown by this button will be clickable and upon selection the user will be prompted to pair with the device giving a success or error message when done depending on whether the external device was successfully paired with our Android device The second button will allow the user to also see a list view similar to the one seen by scan only this will show the devices that the smartphone is already paired with This list will also show clickable devices which will allow the user to disconnect from that paired device or to establish communication between the already paired devices and be able to send data through the formed network The last button 11 will show a settings popup menu which will allow the user to access the Android s Bluetooth functionality and turn the Bluetooth on or off as well as make the device discoverable or visible by other Bluetooth devices In the bottom right of this Main Menu interface will be a small help button that will briefly explain the functionality of each button and the actions performed when any of the buttons are asserted
73. ffen Discern Decide Diffen Compare Anything Diffen Discern Decide N p n d Web 01 Aug 2013 ECE4007 Senior Design ECE4007 Georgia Tech Electrical amp Computer Engineering Senior Design N p n d Web 01 Aug 2013 How Bluetooth Works HowStuffWorks N p n d Web 01 Aug 2013 HTC One Drops by Bluetooth SIG with Android 4 3 Mobile Engadget N p n d Web 01 Aug 2013 Mohamed Safwat Android Code to Control Arduino via Bluetooth Shield turn on off LED Mohamed Safwat Android Code to Control Arduino via Bluetooth Shield turn on off LED N p n d Web 01 Aug 2013 Samsung Galaxy Note II N7100 Full Phone Specifications N p n d Web 01 Aug 2013 Samsung Galaxy S4 Follow Following Phone Arena N p n d Web 01 Aug 2013 Arduino Uno R3 Arduino Uno N p n d Web 01 Aug 2013 MSP430xx1x Family Ti com Texas Instruments n d Web Web 01 Aug Software Http arduino cc Atmel n d Web Web 01 Aug RN 42 Datasheet Sparkfun com Sparkfun n d Web Web 01 Aug
74. forces to move it backwards If the switches are being sent out correctly then the car will move correctly also 84 4 2 1 6 Final Code Logic While working on the project we had made design changes to the car and track for efficiency When the changes were made to these components it caused the overall logic of the MCU to change The main reason for these changes was the movement of the Hall Effect sensors from virtually adjacent with the solenoids to exactly in between them This allowed for a perfect distance of 75 The table below shows the new expected input output expectation of the Hall Effect sensor to solenoid combinations HES Reading Gauss Solenoid 0 2V 1024 200 S N 2V 3V 200 200 Off 3V 5V 200 1024 N S Table 4 2 1 6 In Out Expectation of HES to Electromagnet The microcontroller takes a HES reading between OV and 5V and converts it into a gauss reading that is based on that scale Once the MCU has a Gauss value it changes sets the electromagnet to the correct value Below is the new diagram showing the exact orientation of track magnets to electromagnets This diagram also shows the distance between the HES and Solenoid South North No Field p 4 i Je Foe Gauss gt 220 l E o jose 4 220 lt Gauss lt 220 jer Foe Gauss lt 220 Figure 4 2 1 6 Physical orientation of Solenoids and HES sensors 85 4 4 Android Application Development Architecture
75. g models of our electronic systems Some of the tools included and available in this laboratory for Senior Design students are Oscilloscope Tektronix DPO 4034 Function Generator Tektronix AFG 3022B Digital Multimeter Tektronix DMM 4050 Triple Output Power Supply Agilent E3630A Computer with Simulation Software Resistors Capacitors Diodes Prototyping Bread Boards Wires These tools will be used to simulate the systems three phase linear motion drive system Testing on the Arduino Uno R3 microcontroller circuit will also be done to ensure proper connections and port usage Another Facility will also be used is the machine shop and a member of the group s personal shop and tools The machine shop is available at the UCF campus Some of the tools and Equipment available that will be needed and used are as follows Radial Arm Saw or Table Saw Hole Saw Power Drill Hacksaw File Router Countersink Bit Clamps Vice Soldering Iron Solder The magnetic levitation system will require plenty of building since the entire track and vehicle will be built by hand and the entire design is very meticulous in measurements and fitting Many of these tools will be needed and some that are unforeseen at this stage of the project will also be needed This project also involves a need for software tools Table 6 4 shows a list of the software as well as the version used or that will be used for this project The software used for this proje
76. ge displaying Solenoid Turn spacing for my senior design paper The image is located on 4 p SUBMIT Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties conditions limitations and notices Reproduction of this information with alteration is an unfair and deceptive business practice TI is not responsible or liable for such altered documentation Information of third parties may be subject to additional restrictions Bibliography Arduino ProtoShield Kit Arduino ProtoShield Kit N p n d Web 30 July 2013 Continuous Time Ratiometric Linear Hall Effect Sensor ICs N p Allegro MicroSystems n d PDF DC Motor Control Using an H Bridge Physical Computing at ITP N p 24 Oct 2011 Web 30 July 2013 Hallogic Hall Effect Sensors Type OHO9OU N p OPTEK Technology May 1996 PDF McLyman William T Transformer and Inductor Design Handbook Boca Raton etc CRC Taylor amp Francis Group 2011 Print SN754410 Quadruple Half H Driver N p Texas Instruments 2008 PDF US1881 Hall Latch High Sensitivity N p Melexis Jan 2006 PDF Android bluetooth Android Developers N p n d Web 01 Aug 2013 Apple Developer IOS Developer Program N p n d Web 01 Aug 2013 Client server Model Wikipedia Wikimedia Foundation 30 July 2013 Web 01 Aug 2013 Diffen Compare Anything Di
77. gram continued 92 Figure 4 5 1 Communication through System Model 94 Figure 4 5 3 Client Server Model 96 Figure 5 1 1 Connections between the A1301 sensors and Arduino Board 99 Figure 5 1 2 Connections between the Arduino H Bridge drivers and Solenoids 100 Figure 5 1 3 Connections between the Arduino and RN41 101 Figure 5 1 3 1 Total Eagle Schematic 102 Figure 5 2 Final Schematic 104 Figure 6 2 Circuit for testing the A1301UA sensors 106 Figure 7 2 4 Financing 120 Tables Table 3 2 1 2a Configuration Values Table 3 2 1 2b Switch and Pin Setup Table 3 2 1 3b RN 52 Pin table Table 3 2 2 2 Android vs iPhone Development Table Table 3 2 3 2 Comparison chart Bluetooth vs Wi Fi Table 3 2 7 1 Pin Numbers and Functions Table 3 2 8 1 3 Pin connections of the Allegro A1301 Table 6 3 2 Bluetooth Controller Communication Test Table Table 6 3 3 Hall effect reading Test Table Table 6 3 4 H Bridge Control Test Table Table 6 3 6 System function Test Table Table 6 3 7 Prototype Test Table Table 6 4 Software Summary Table 7 2 4 Financial Table 1 0 Executive Summary Magnetic levitation or otherwise known as maglev technology is a system where propulsion is achieved through magnetic fields This technology does not use any mechanical method of propulsion such as wheels axles et cetera Our design proposal is that of a scaled down version of the maglev train technology that is in its infancy tod
78. h array system in use today is the Inductrack system The Inductrack halbach array makes use of permanent magnets that pass over unpowered loops of wire called Litz wires The Litz wires are made of up smaller wire strands that are woven in distinct patters to carry AC current The halbach array passes over these magnets and thus levitation is achieved 64 Figure 4 7 Rough sketch of the passive coils used in the Inductrack rail system This is a 3 phase winding In order to get the vehicle to levitate on its own it needed to be subject to a magnetic field of the same polarity as the magnets equipped on the vehicle However since there are two arrays of magnets that are attached to the track the levitation array and the propulsion array it is necessary to minimize the flux in all other directions besides upwards If the magnetic field from the levitation array were to cross the magnetic field from the propulsion array there would be interference which could compromise the entire vehicle In the event of interference the flux would be distorted by the surrounding magnets that are located in the propulsion array and possible the other magnets that are located in the levitation array This distortion could possibly e Negatively affect the levitation on the car e Adverse effects relating to the propulsion These types of adverse reactions can have unforeseen complications during building and testing of the track vehicle and the tende
79. he Linimo While the Transrapid and Linimo systems are the only two commercial maglev systems both South Korea and China have plans to construct native maglev systems which would bring the total to 4 operational commercial maglev systems There are currently 3 different types of maglev rail technology These are Electromagnetic Suspension EMS Electrodynamic Suspension EDS and Inductrack Permanent magnetic suspension EMS uses electromagnets whose magnetic field is monitored and altered via a feedback loop EDS uses on board superconducting magnets that are super cooled in tandem with magnets built into the track The magnetic field in EDS technology is extremely strong and as a result the fastest train speeds have been achieved by EDS trains 581 km h 361mph However due to the strength of the magnetic fields there are both medical and equipment hazards with EDS The Inductrack technology uses a permanent magnet array to keep the train levitated while passive coils in the track provide the linear motion when the permanent array passes above the coils The permanent magnet array in the Inductrack is a Halbach array which is used to direct the magnetic field in a general direction by canceling out unwanted fields Inductrack is more suited towards lower speed operations but is the most reliable of the three types of maglev technologies guidance magnet guideway stator 1 Figure 2 1 EMS techn
80. he RN 52 and the Atmega328 and the code in place for the MCU to take the value we will test it through the registers Below we have a table that our group will follow and fill out to determine if communication was successful Button pressed Signal Sent Signal recieved Signal Correct on app Expected Y N result Speed 1 000 Speed 2 001 Speed 3 010 Brake 011 Reverse 100 Table 6 3 2 Bluetooth Controller Communication Test Table All we have to in order to test is send the signal through and test whether the MCU recorded the correct value in the register chosen For example we will simply send the value from the Bluetooth controller of 01 and we will save that value into a variable of control_signal The way our group will determine if it recorded the correct signal is by pausing the MCU program and check the value of the variable control_signal If the signal was sent as 01 and the variable reads as 01 then we will know it was successful If this is not what the variable reads then we know that we will need to fix it 107 6 3 3 Testing Hall Effect sensor to the Atmega328 Another simple section that is essential to our maglev vehicle running is the analog value being sent from the Hall Effect sensor to the MCU This means that we will have to compare the expected reading of the Hall Effect sensor to the reading that our Atmega328 receives The way will determine if the signal is being
81. hese bricks and maybe a few more depending on what is needed when building the car actually begins the base and foundation of the car will be built Thought also needs to go into housing the two Neodymium magnets that will cause levitation above the track Since no one in the group has access to a substantial amount of Legos and buying individual Lego bricks per design could get expensive we will not be building our car using Lego parts 4 1 3 2 Wood Design The other option for building the car is just prototyping out of wood The type of wood is up for consideration a few factors should be considered when purchasing the material e Price e Hardness durability e Ease of cutting We will have access to power tools but the less labor required the more productive the team will ultimately be The wood block that will be purchased has the following dimensions which if not available can be cut with a table saw to scale down to a 7 x 4 x 5 wood block For the car foundation hardwood would be ideal because drilling and shaping needs to be done to glue the permanent magnets to the bottom of the wood block Balsa wood is too soft for our purposes but was considered Pine will be 70 used instead and if it is not possible to obtain the correct dimensions we need two pieces can be cut and spliced together 4 1 4 Car Prototype Diagrams 4 1 4 1 First Car Prototype The group s first design idea included four magnets that would
82. hould be about 2 in length cuts for each solenoid A handsaw for metal cutting will work but is a labor intensive process These pipe sections must then be made into spools by attaching aluminum or another type of cut out which should fit the tubing size and extend about 1 2 to an 1 above the outer diameter of the solenoid tube Use more 2 part epoxy to secure 10 The Solenoids must now be wound This will be time consuming as to the fact that the team will be winding over a 1000 feet in total of copper A winding drill should be utilized to lessen labor Keeping the windings tight is important as well every so often a bead of glue should be utilized to keep the winding close and intact Before the channel is attached to the underside of the car all the wiring for the Hall Effect sensors solenoids and H bridge drivers should be done and organized so that once the channel is screwed in place there will not be a need to take off again 12 The housing for the MCU and PCB board will be created from leftover plexiglass after creation of the track It will be roughly four inches tall and be wide enough to fit the 3 x 2 Arduino board with the stackable Protoshield 74 4 2 Microcontroller programming If we plan on completing our design we need to know what we will get out of having a microcontroller As described earlier we will need it to be taking analog inputs and use that information to send the correct signals out
83. hows a block diagram obtained from the A1301 datasheet Feedback is used to obtain more precise Vout measurements The voltage reading is then amplified and filtered to obtain a corresponding voltage field ratio VOUT CBYPASS Figure 3 2 8 1 1 The functional block diagram of an Allegro A1301 Hall effect sensor IC Reprinted with permission from Allegro Microsystems The operation of the A1301 is highly similar to the example described in the first paragraph of this section The A1301 operates around its Quiescent Output Voltage which is half of the supply voltage This supply voltage around 5V will be fed through the microcontroller So half of this voltage will be the Quiescent Output Voltage 2 5V For this sensor the presence of an S polarity magnetic 42 field B increases Vout This will continue to increase until which Vout reaches the Vcc rail which is 5V or the supply voltage The presence of an N polarity magnetic field B decreases Vout towards OV The magnetic sensitivity of this sensor can effectively be described by this equation Sensistivity Vout B Vout B 2B It will be important to note that when the supply voltage varries the field sensitivity will also change as shown in this graph from the A1301 datasheet This will be important to consider if the voltage in our battery is dropping and the readings become therefore inaccurate due to change in field sensitivity 1301 Device Sensitivity vs Supply Volt
84. icrocontroller that exceeds our project expectations because we can We have to find the cheapest one that meets our requirements This also refers to components that might be included in the board and MCU such as a Bluetooth device If an integrated board wireless device and MCU package is cheaper than buying the parts individually it might be considered Analog digital converter As of right now we will have analog inputs This means that our car will need analog inputs to work with the Hall Effect sensors Most of the msp430 parts do not support analog naturally which means we will have to narrow the search to correctly find a specific model Since that greatly limits the number of models we are able to look at it changes what our group might have been thinking for the MCU Since the arduino board with the ATmega328 has 6 analog inputs ready it already complies with the requirements Voltage and current Since our power supply will be on the vehicle we need to know what the MCU s requirements are The Atmega328 has a Built in 100 mA regulated power supply that accepts an input voltage ranging from 7v to 24v This also has a 5V output The MSP430 site says 1 8 3 6V operation which is significantly 18 lower than the Atmega328 which might mean that we could use more of our power source for moving the vehicle rather than the control system Compiler program Obviously our ability to program the MCU is of huge imp
85. in order to control our vehicle We will use the diagrams for port values that we have found along with schematics we ve created to code our MCU in order to complete our tasks 4 2 1 Programming functions 4 2 1 1 Receiving order from Bluetooth controller The first step for the MCU to function our car is simply to receive a signal Our microcontroller will be controlling this system but its directions will be received from a Bluetooth controller device We expect that this will be something along the lines of a simple phone app that connects to the MCU wirelessly It will not connect wireless directly because the Atmega328 does not have an on board wireless device The way we will connect the Atmega328 to the Bluetooth controller is through the RN 52 The RN 52 is a Bluetooth enabled information medium for this specific purpose So the code and wiring involved for the Atmega328 will be for the RN 52 device and not the controller directly UARTTX UARTRX Atmega328P Take input control_inO digitalread D12 Figure 4 2 1 1 Bluetooth Block diagram Following the diagram above we can see the UARTTX and the UARTRX ports of the RN 52 connected to the Atmega328 through the digital input ports of D12 and D13 Once the devices are connected properly we will need a code to direct the Atmega328 to take an input This code will follow the pattern of the code shown in the figure above Digitalread port will take a value being in
86. ishing connection with the correct device as there may be other devices in range during testing such as other smartphones so information about the devices is important OnReceive method Will allow the user to decide what happens when the information is received Private final BroadcastReceiver mReceiver new BroadcastReceiver public void onReceive Context context Intent intent String action intent getAction When discovery finds a device if BluetoothDevice ACTION FOUND equals action Get the BluetoothDevice object from the Intent BluetoothDevice device intent getParcelableExtra BluetoothDevice EXTRA_ DEVICE Add name and address to an array adapter to show in a ListView mArrayAdapter add device getName n device getAddress H IntentFilter object This is needed to register the broadcast receiver 88 Register the BroadcastReceiver IntentFilter filter newIntentFilter BluetoothDevice ACTION FOUND Controller Class The Controller class will be the main activity and interface through which the user will interact wirelessly and control the magnetic levitation vehicle Through this activity as it is called by the Integrated Development Environment the user will be able to send commands and receive information about the vehicle All of these commands and information will be handled by the system or the vehicle s microcontroller e Forward Thi
87. ite track e Can only showcase high speed provided the track is long enough e Along track is cumbersome to transport Levitation array Levitation magnet array Figure 4 1 Rough sketch of straight track initial design Top view shown with segmented areas to show permanent magnet location These magnets would provide the necessary levitation needed for the vehicle Circular track advantages e Infinite track length e Can showcase high speed maglev capabilities without restrictions e Amore compact design allows for easier transportation 55 Circular track disadvantages e Circular design will prove challenging to construct e Levitation and propulsion arrays will prove problematic when fitting to the track Levitation array Figure 4 2 Initial circular track design Shown is a top view of the track with segmented areas to show permanent magnet configuration which provides the levitation needed for the vehicle Taking all of the advantages and disadvantages of the straight track design and the circular track design into consideration the group decided to combine the two designs into a track resembling a NASCAR track The final track design would be consisted of two straightaways and two curved areas The group felt that the amalgamation of the straight track and circular track would be the most ideal due to the advantages of both of the tracks Both tracks had ideal advantages that would allow for adequate
88. ith creating an EDS track is the cost The magnets are cooled with a mixture of liquid nitrogen and helium to create the superconductor The cost alone was enough to put this track design in the realm of non feasibility but the limitations did not stop there The magnetic fields created by the EDS systems are so strong that it creates health hazards for certain people People with pacemakers are affected by the magnetic field creating the need for magnetic shielding Also cellphones credit cards magnetic strips et cetera would also be compromised by the magnetic field Finally assuming that cost and health hazards were not issues the speeds that an EDS rail system can achieve are ridiculously fast So fast that in terms of a senior design project is dangerous and not feasibly by any means While EDS tracks are technologically sophisticated and capable of extraordinary feats this track design was not feasible for what our project called for Initial track design Inductrack The final track design idea was based off of the Inductrack rail system As explained in the introductory section the Inductrack is a passive rail system that uses unpowered loops of coil for the main track while the vehicle is fitted with permanent magnets arranged into a Halbach array The interaction between the magnets on the vehicle and the track creates levitation The group deviated from the typical Inductrack design which calls for passive coils and instead used
89. ith similar projects as the one at hand With an analog controller there is the option of using an already built control and modify that for the system There are plenty of controllers that can be used for modification such as a Wii controller or any other gaming system controller Also using a remote controller for any remote controlled toy car can also be modified to fit this system Secondly we could use an already owned smartphone to control the vehicle This option brings a more up to date approach given the advances of smartphones in our generation An advantage to using a smartphone is these devices already monitor time in real time which will be adequate for the speed measurements Lastly we could control the system through a laptop PC Although the analog controller would require more parts and more costs there are sources to help the group with this part of the system that were specifically relevant to this project On the other hand the smartphone being used as a controller is a popular subject for our generation and therefore seemed more appropriate to use in this project Using a laptop would require building a website and setting up a server as well as using Wi Fi since the choice of connection was wireless Depending on a server host is an extra cost and somewhat risky based upon internet connection In the end the decision of the team was to expand the project and further emphasize the design by developing a smartphone applicatio
90. ity to use it in the project will be limited to what we can learn With the ATmega328 the user manual is very understandable and well laid out but somewhat limited in terms of how much information is actually given On the other hand the MSP430 user guide is much longer with descriptive details about every feature of the MSP430 Even though it is much more detail it 19 is not laid out as understandably in terms of use It doesn t have the same description Ease of use Knowing how easy it is to use each of the MCU s along with each of the board possibilities is very important If we cannot get our microcontroller to work the whole project will not work Knowing how to use the compiler in order to program our microcontroller is essential Having to learn a new program for the Atmega328 is going to be a task whereas in the MSP430 we already know code composer studio so we can handle programming it Also having the correct schematics for each of the ports of the microcontrollers is essential We will need to understand all of these things to make the best decision 3 2 1 1 Atmega328 Other features We plan on using each one of the features available for a specific part of the project As we said earlier in the project optimization comes from using each of the possible features to its optimal potential This choice was made simply because our group was on a budget and we knew it was necessary to spend the least amount of money but still
91. l and error The best range for this voltage will be noticeable because the motion of the car will be smooth instead of erratic 3 5 3 Leaving N Pole B magnet Once the threshold Voltage is passed again the solenoid will turn back on and have an N S orientation pushing off the N pole magnet The N pole magnet will push away the solenoid until it is attracted by the next S pole magnet Phase 1 Phase 2 Phase3 1 0 0 5 0 0 0 5 1 0 120 120 a gt MH Figure 3 5 Three Phase sinusoidal wave diagram 50 3 5 4 Test Case Scenarios for the Drive System This section is devoted to analyzing a number of cases for the three solenoid s operations Each case will be a hypothetical snapshot in time and will show ideal cases for the current state of solenoid operation The three states are OFF N S and S N orientation The table in figure 3 5 4 highlights six of the cases that will occur as the vehicle is propelled down the track At any point in time there will be two sensors reading above the quiescent voltage of 2 5V and one sensor reading below or vice versa two below 2 5V and one above The only exception would be when one of the solenoids detects no field and the other two are above and below 2 5V respectively These test cases cover 360 degrees of operation at the 6 points where one of the solenoids is off Sample case Voltage Solenoid 1 bei
92. le magnet Because of this fact we will not be using this sensor bi polar functionality is a must when interfacing with the MCU and achieving the control we desire with the motion 3 2 8 3 Melexis US1881 This sensor has a digital output and a wide operating voltage range 3 5V to 24V unlike the linear sensor A1301 Because it has a digital output it is similar in regards to the OHO9OU but the key difference is that this sensor functions as a bi polar latching Hall effect sensor The latching effect could be explained as such when an S pole approaches the sensor it turns on and only changes state when an equal in magnitude N pole magnetic field comes within range Figure 3 2 8 3 Allegro Optek Melexis A1301 OHO90U US1881 Operating 4 5 6 4 5 24 3 5 24 voltage V Polarity Bi polar Uni polar Bi polar Output type Analog Digital Digital Linear Magnetic 2 5 N A N A sensitivity mV Gauss Magnetic N A 90 60 operating point Gauss Magnetic N A 65 60 release point Gauss Quiescent 2 5 0 0 Output Voltage B 0 V Figure 3 2 8 3 Comparison of useful specifications of the three hall effect sensors 44 3 3 Levitation 3 3 1 Static vs Electromagnets In the case of providing levitation we were faced with choosing either static passive magnets or electromagnets This decision came down to the type of design plan we wanted to base the project on Inductrack uses passive static magnets
93. linear motion via a magnetic field by either manipulating the current in a linear motor attached to the vehicle or manipulating the current in the track By doing this we manipulate the poles of the electromagnets to create a push pull effect which in turn creates linear motion e To control the system using a mobile interface either Android or IOS These objectives are the core to our project and will be met in the fullest This proposal will investigate the techniques to achieve linear motion in greater detail in the appropriate sections Either way both paths can yield linear motion provided we design our project efficiently 2 3 Project Requirements and Specifications The main requirements for this project are as follows e Must achieve levitation and linear motion without any manual interference or stability such as wheels axles hands et cetera e Must be controlled via a mobile device The type of device will be expanded upon in the later sections of the proposal That being said the mobile device is narrowed down to two types these being an Android system or an IPhone IOS system e Must stay on the track The entire point of the maglev train system is to achieve linear motion via magnets along a guided path If the vehicle falls off the track then the project is not properly demonstrating the capabilities of maglev technology The specifications of the project will be elaborated on in the later sections of the proposal These
94. ller and Remote In order for the remote controller which will be the smartphone to interface and send commands to the vehicle it must consolidate with the microcontroller which will be directly handling the vehicle s motion The method through which the remote controller will interface with the microcontroller is Bluetooth communication The Atmel Atmega Arduino Uno board will be used as the microcontroller A Bluetooth module will be added to the Arduino board to support Bluetooth communication 4 5 1 General Communication through the System Figure 4 5 1 shows an outline of the interaction between each interfacing technology in the entire system and how each of these technologies will work The maglev vehicle will be on the magnetic track and levitate using magnetic levitation It will be controlled by the Arduino microcontroller which will be powered by a 12 volt battery The microcontroller will have pre programmed command inputs that will be received via wireless communication Bluetooth In order for the microcontroller to support Bluetooth an add on module is added to the board It will be a Bluetooth module which will serve as the slave for the Arduino Uno microcontroller board The Bluetooth module will serve as a hallway with the purpose of exchanging information between the smartphone serving as the remote controller and the board Communication through System Model Arduino Android Device Wireless Bluetooth Communicatio
95. lly a passive system There is no outside power source to generate a magnetic field it is done entirely via the magnets The key for a successful Halbach array however is creating a proper arrangement so that the magnetic fields are rotating spatially to negate one side of the field g ma b s C Magnetic field above rods Magnetic rod Magnetization vector Alternating rod rotation of 90 e rs Ps Te lt gt lt gt Magnetic field below rods Figure 2 6 An example of a Halbach array using magnetic rods Note the directions of the magnetic fields to achieve the desired resultant field Reprinted with permission under the Creative Commons Attribution ShareAlike license 2 3 1 1 Vehicle The vehicle will have 4 permanent magnets attached to each corner These magnets will be attached to the vehicle in such a way that when the vehicle is placed on the track the magnets will be situated on top of the track magnets Due to the track magnets being arranged in a Halbach array the magnetic field emanating from the track will be directed upwards towards the vehicle The magnets in the vehicle will then repel against the track magnets creating the necessary levitation needed to replicate the maglev technologies 2 3 1 2 Track The track will be structured in such a way to facilitate a vehicle that will be operated by maglev technology D
96. mbers ranging from 1 to 3 inclusive This is how speed will be executed in the track To keep the vehicle from possibly going to fast on the track and leveling off the track the group has defined three speeds for each direction So after testing purposes for example if the maximum safe speed of the vehicle is 6 mph then that speed will be divided into three phases identified as e First Speed e Medium Speed e Max Speed Going off the example of a max speed of 6 mph this would respectively be identified as the third speed or Max speed The Medium speed will be identified as 4 mph and the First speed will of identified as 2 mph So calculations of the First and Medium Speed will be based on the safest maximum speed the vehicle can move about the track The associative commands for the speeds are 1 2 and 3 where 1 is First speed 2 is Medium speed and 3 is Max speed The second command Back will be identified by the range of numbers between 4 and 6 inclusive This will work the same as the Forward command where 4 will be equal to First speed 5 to Medium speed and 6 to Max speed Only in this mode the vehicle will be going in the opposite direction or backwards The third command Stop will be identified by the integer 0 This command will enable to vehicle to come to a complete stop when it is in motion and regardless of the speed of the vehicle when the command is given This is done so no unnecessary amount of data will be sen
97. n Figure 4 5 1 93 4 5 2 Establishing a Connection The Android smartphone will initiate a connection between itself and the Bluetooth module The smartphone will send a radio frequency to any Bluetooth supported device in order to establish communication Once the Bluetooth module is on and ready to receive this signal a connection can then be made and communication can then take place where the Bluetooth module will serve as the slave and the Android smartphone will serve as the master This entittement is appropriate since the smartphone is the controlling device establishing the connection and deciding when to send and retrieve information The Bluetooth module itself waits for commands from the smartphone Four requirements must be met in order for this connection to take place e The smartphone must be in discoverable mode e The Bluetooth Module must be on e The smartphone must know the mac address of the Bluetooth module device e Both devices must be within range Approximately 30 feet from each other After these requirements are met then these devices can successfully communicate with each other as well as exchange the necessary information Since the group is using the Client Server model to establish a connection between the smartphone and the Bluetooth module adapter for the microcontroller one device has to act as the server while the other behaves as the client or the central caller The client server model presents an
98. n In this case since we have knowledge of the MSP430 having used it before this is the one we were leaning towards That being said the most descriptive project that we found which had a very huge impact in our design uses the ATmega328 with the Arduino Uno Revision 3 board Obviously we will choose the one that fits the projects needs but one of the needs is for the group to be able to use it properly Dimensions Dimensions refer to the board more than the microcontroller The board we will eventually use has to be small enough to fit on our vehicle but also large enough to be able to configure all the wiring we need At this specific time do not know every requirement that exists in terms of how large it must be but because of the vehicle size limitations we have a maximum size of the board Our car should not be larger than 8 10 inches long and 3 4 inches wide depending on track size This means that when our board is placed on the car along with other components it has to be small enough to fit estimate that our board should not be larger than 5 inches long and 3 inches wide Given that a majority of premade boards are much smaller than these requirements our requirements should be met Optimal cost Optimal cost is pretty self explanatory we must make sure that the microcontroller and board meet the requirements without going overboard to increase cost This means that we don t need to spend a ton of money on a ridiculous m
99. n constant while the vehicle travels from the initial straightaway through the arc and into the next straightaway The arc segments were designed to have a curvature of 90 This was done to demonstrate the level of control the vehicle can maintain while traveling at high speeds due to the nature of the propulsion 57 Radius Figure 4 4 The arc dimensions shown The diameter of each arc is 1ft while the angle of curvature is 90 rl ss e j TON ee E eMM 2ft Figure 4 5 Straightaway dimensions shown Shown is the corridor width overall track width and straightaway length The total distance of the track is as follows Total straightaway distance 4ft Arc section distance 2 pi r 3 141592654 ft Total arc distance 6 283183507 ft Total track distance 10 283183507 ft 58 Final track design choice While it was decided after looking at all of the track design layouts that the NASCAR track design was the ideal choice to showcase all of the desired plans and outcomes for the project the final design chosen was the straight track The straight track was chosen based on e Cost e Design simplicity e Adequate design functionality The main cause of the design change was motivated primarily by the cost of the permanent magnets The NASCAR track would require 2 straight aways and 2 curved sections This would at the absolute least triple the cost of the project and the group was not able to facilitate that type
100. n the android smartphone and the microcontroller through the Bluetooth module Below is the definition of the main objects and methods and examples of how they will be coded in the Android application 87 BluetoothAdapter object Allows the application to interact with the Bluetooth software already present in the smartphone This then allows the user to enable Bluetooth directly through the application BluetoothAdapter BtAdapter BluetoothAdapter getDefaultAdapter If BtAdapter null Bluetooth is not supported by device If BtAdapter isEnabled Intent enableBtIntent new Intent BluetoothAdapter ACTION REQUEST ENABLE startActivityForResult enableBTIntent REQUEST ENABLE BT Devices Set Will keep track of the paired devices with the smartphone In this application the user is only interested in the specific micro controlling system for the magnetic levitation vehicle Set lt BluetoothDevice gt Devices BTAdapter getBondedDevices Tf any paired devices if Devices size gt 0 loop through the paired devices for BluetoothDevice d Devices Add name and address to array mArrayAdapter add d getName n device getAddress BroadcastReceiver object Once the device begins to discover new devices in range it is necessary to gather information about each device The user wants to make sure that it is establ
101. n to control the vehicle 2 3 3 Android Application Interface The Android application needs to have several functionalities and specifications in order to function properly and execute the tasks by which it was created The application s purpose is to establish a wireless connection between the remote controller the smartphone itself and the magnetic levitation vehicle more specifically the microcontroller which will be sending the signals to the vehicle This Bluetooth application will need to send commands that will make the vehicle move around the track The three commands that will be given are forward backward and stop The Android application will also receive information from the vehicle such as the location on the track which will be used to determine the speed of magnetic levitation vehicle To begin developing the application for Android one needs to use the Android Bluetooth APIs Application Programming Interface which allows the access of Bluetooth functionalities already encompassed in the Android smartphone These APIs allows users to scan for other Bluetooth devices query the local Bluetooth adapter for paired Bluetooth devices establish RFCOMM channels connect to 10 other devices through service discovery transfer data to and from other devices and manage multiple connections These APIS are available in the android bluetooth package The library consists of the following classes and interfaces which will be envel
102. ncy of motion relating to the vehicle as it passes through the magnetic flux of the propulsion arrays Also the tendency of levitation can come under scrutiny if these adverse reactions were allowed to take place Shown in the figure below is an example of a Halbach array that showcases the tendency of the magnetic flux 65 1 402e 000 gt 1 476e 000 1 329e 000 1 402e 000 1 255e 000 1 329e 000 1 181e 000 1 255e 000 1 107e 000 1 181e 000 1 033e 000 1 107e 000 22 2 219e 001 1 481e 001 lt 5 078e 004 7 429e 002 Density Plot 8 Tesla Figure 4 8 A halbach array using neodymium magnets The orientation of the magnets effectively nullifies the flux on the bottom side while the flux on the top side is reinforced and directed The flux on the bottom can never truly be reduced to zero As noted in the picture a magnetic flux exists albeit weak Reprinted with permission under the Creative Commons CCO 1 0 Universal Public Domain Dedication To avoid this the magnets are arranged so that the flux above the magnets is reinforced and directed while the flux below the magnets is nullified as close to zero as physically possible This is the fundamental of the Halbach array By localizing and reinforcing the flux upwards the field is directed towards the undercarriage of the car The flux on the magnets on the car would be directed downwards by equipping the undercarriage of the car with magnets that are magnetiz
103. neering and Computer Science at the University of Central Florida The testing lab is not only a good location for each group member to meet easily but it also already contains the equipment we will need to appropriately test our parts The equipment needed will be a Multimeter oscilloscope and Power 103 supply These devices will help us in creating the simulated environments for each part of the system 6 2 Testing the Hall Effect Sensors It will be important that when the team receives the individual sensors that we test them to see if they indeed do react linearly in the presence of one of our magnets This could be done by setting up a simple breadboard circuit This circuit shown in figure 6 1 will have power running through the Arduino Board to the A1301 Hall effect sensor The output of the Hall Effect sensor will connect through a resistor connected in series to a 5mm LED To verify functionality of the sensors the LED s brightness should increase when an S pole oriented magnet approaches the sensor Its brightest point should be when it is closest and the sensor should output 5V When no magnet is present the LED should be dimly lit at all times while power is connected As an N pole oriented magnet approaches the Hall Effect sensor the LED should steadily turn off until it is finally out as the N pole magnet is directly next to it Figure 6 2 Circuit for testing the A1301UA sensors 104 6 3 System testing As stated
104. ng printing and binding of the pages commences e 8 1 Final report is due by 9 50 AM 113 Fall 2013 8 19 Order building parts for the track and car to start construction 8 26 Begin construction of track and car 9 16 Wire Solenoids 9 20 Order electrical parts the rest of the parts that haven t been acquired 9 30 Breadboard circuits for hall effect sensors LED s and H bridge IC s e 10 14 Once final breadboard circuit is working correctly solder the parts to the Arduino Protoshield Channel wiring to and from the solenoids e 10 17 Develop code algorithms and implement onto the microprocessor e 11 11 Testing Debugging implement safety precautions e 11 28 Prepare Final Documentation and Presentation 7 2 Budget and Finance This section will discuss the budget and the financing of the maglev project The sections that will be covered are e Track budget and finance e Vehicle budget and finance e Miscellaneous budget and finance 7 2 1 Track budget and finance During the design process the features of the track were broken down into sub sections for budget distribution These were Track materials Frame Fiberboard Acrylic housing Permanent magnets Levitation magnets Neodymium or rubber magnetic strips tentative e Propulsion magnets Neodymium magnets The group decided to allocate the largest amount of funds dedicated to it as the materials run the most expensive out of the entire project
105. ng front State Off N S or S and 3 being back N 1 3 75V 1 N S OV 2 OFF 3 75V 3 S N 2 5V 1 OFF 1 25V 2 N S 1 25V 3 S N 3 3 75V 1 S N 3 75V 2 N S OV 3 OFF 4 1 25V 1 S N 5V 2 OFF 1 25V 3 N S 5 OV 1 OFF 3 75V 2 S N 3 75V 3 N S 6 1 25V 1 N S 1 25V 2 S N 5V 3 OFF Figure 3 5 4 4 1 Initial Design Architecture This section deals with all of the specific details regarding all of the hardware and software of the project The hardware of the project consists of the track the vehicle the solenoid propulsion design on the vehicle the MCU apparatus the power mechanism and the Bluetooth connectivity hardware The software is all of the code related to the project 51 4 1 1 Track design The track is a large and significant portion of this project It houses the necessary components that give life to a maglev vehicle This section will discuss the initial design ideas and procedures that went in to the track The first track design ideas were taken from the existing maglev train systems in use today Electromagnetic suspension EMS Electrodynamic suspension EDS and Inductrack Each track system has a different type of suspension levitation system that was discussed in the introductory sections Initial track design Electromagnetic Suspension The EMS track design was our first design proposal for the track The EMS track uses electromagnets built into the train vehicle while the track is fitted with ei
106. nior design group from Georgia Tech In this system this group attempts to design a smaller version of a magnetic 15 levitation train that would be a prospective technology in the real world of transportation This group uses a small train car a track with a magnetic strip neodymium sik magnets for propulsion and levitation purposes a linear synchronous motor AC drive for the variable three phase current source an AC reactor and resistors There system reaches levitation of 2 4 mm above the track and a speed of 1 mph Braking is induced by decreasing the frequency of the AC drive This Georgia Tech group s main goals were to Power the AC Drive to provide the variable 3 phase current Setting the switch to control direction of flow of current in the LSM Gently pushing the train car to provide an initial momentum Controlling the frequency on the AC Drive to provide acceleration deceleration There system or more specifically there vehicle was physically powered or pushed on initial demonstration to get the vehicle in motion No remote controller was used to initiate the vehicle s movement across the track in comparison to the Antipode team where an analog remote controller with antennas was used to communicate with the vehicle Conclusions on Related Work Most of the related work and projects use similar features of the magnetic levitation design and basically all consist of the same foundation Where levitation is achieved thr
107. nsors LED s were not utilized to indicate direction this was purely done through the android app that was created Figure 5 2 shows the final schematic that we used for the Mag Lev project Diodes were not needed on the h bridge outputs for current fly back protection because the supply voltage is not greater than 24 V 102 j al Figure 5 2 Final schematic 6 0 Project Prototype Testing Once we have started building our project we will have to know if each part is working properly If we were to build the entire project then realize it didn t work we would not know which part isn t working and therefore not know which part we need to fix This has led our group to decide that we will be testing each piece in its most basic form This means that before connecting any raw materials together we will know that it the correct signal is being sent or received Then once each piece is tested we will connect them one by one in order to determine that each connection is functioning properly also 6 1 Hardware Testing Environment The first thing we will need in order to test our hardware is a good environment This means that it will be is a good location with proper equipment The testing will mostly take place in the Senior Design lab provided by the College of Engi
108. od is extremely susceptible to water which could potentially cause catastrophic damage to the track and any surrounding electronic equipment With acrylic the material itself is weatherproof This way any exposed corners and edges can be sealed off to create a weatherproof seal for the components housed inside the track While acrylic and polycarbonate offer substantial benefits in the realm of creating a sturdy lightweight track the team discovered crippling disadvantages to creating an entire track out of these materials The disadvantages of acrylic and polycarbonate e Cost e Ease of fabrication e Handling fabrication The main detractor from using either of these materials is the cost Acrylic and polycarbonate sheets are quite expensive for the amount you get Fabricating structures with acrylic and polycarbonate can be somewhat problematic as well If using the wrong tools the materials can split and crack in unwanted areas and could potentially compromise the rest of the structure While building a track made from entirely acrylic and or polycarbonate is not in the realm of feasibility the utility that these materials offer more than makes up for the disadvantages For the propulsion magnets which will be discussed in detail in the Track Dynamics section it was decided that polycarbonate was to be used to house the Halbach array 61 Track Material Wood substitute Fiberboard The group decided that while wood itself woul
109. olenoid Polarity and H Bridge Function 6 3 5 Testing Atmega328P Output to H Bridge Circuit 6 3 6 Hall Effect Sensor through Solenoid function 6 3 7 Final Prototype Testing 6 4 Facilities and Equipment 6 5 Conclusion 7 0 Administrative Content 7 1 Milestone Discussion 7 2 Budget and Finance Discussion 7 2 1 Vehicle 7 2 2 Track 7 2 3 Other features 7 2 4 Financial Diagram 7 3 Bill of Materials Figures Figure 2 1 EMS technology for the maglev rail Figure 2 2 EDS technology for the maglev rail Figure 2 3 1 Inductrack technology Figure 2 4 The JR Maglev design Figure 2 5 Halbach array fundamentals Figure 2 6 An example of a Halbach array using magnetic rods Figure 2 3 3 1 Main Menu Figure 2 3 3 2 Controlling Interface Figure 3 2 1 2a RN 42 Block diagram Figure 3 2 1 2b Pin Diagram Figure 3 2 1 3a RN 52 Pin Diagram Figure 3 2 4 Magnetic Field intensity Figure 3 2 5 Tightly Spaced turns vs loosely spaced turns of a solenoid Figure 3 2 6 1 Scenario 1 1 S1 high and S2 Low Figure 3 2 6 2 Scenario 2 S2 high and S1 Low Figure 3 2 7 Pin layout for the TI SN754410 Figure 3 2 7 1 1 TI SN754410 diagram Figure 3 2 8 1 1 The functional block diagram of an Allegro A1301 Figure 3 2 8 1 2 Graph of the Magnetic Sensitivity Figure 3 2 8 3 Specifications of the three hall effect sensors Figure 3 1 Magnetic Force vs Distance chart Figure 3 2 A simple electromagnet Figu
110. olenoid to be turned off Finally if the command received from the Bluetooth controller is to brake we will need the solenoids to be oriented to the magnet it is aligned with in order to hold itself to that specific part of the track 79 Just passed a N polarized magnet Below we have a diagram of switch signals whenever the MCU has determined it has just passed by an N magnet Figure 4 1 1 46 NS magnet block diagram In the diagram we can see every feature of the magnetic pull that we intend to occur It begins simply by toggling the output value on the MCU it will lead to the pull of the magnet Since the solenoid just passed an N polarized magnet we 80 changed the switch values to match what they would need to be in order to create movement The switches changed in the H Bridge circuit allow the current to go through the solenoid in the intended fashion causing it to be N based on this side Remember that since magnets are double sided the solenoid will have a mirrored orientation on the opposite side Just passed S polarized magnet Below we have the diagram of switch signals whenever the MCU has determined it has just passed by an S magnet Figure 4 1 1 4c SN magnet block diagram 81 This step is similar to step previous but instead we just passed an S polarized magnet therefore we need the circuit to change so that the solenoid is S polarized for the intended forces We can see that simply by changing the value
111. ology for the maglev rail Reprinted with permission under the Creative Commons Attribution Noncommercial ShareAlike license Internal Workings of the Maglev Train ressor Unit in Car mounted Com Bogie Helium Refrigeration System Levitation Frame Guida Air Coil Spring Auxiliary Guiding Gear Auxiliary Supporting gt Liquid Nitrogen a Outer Propulsion man Boil Liquid Helium ig Supporter Radiation Inner Vessel 1 Shield Figure 2 2 EDS technology for the maglev rail Reprinted with permission under the Creative Commons Attribution Noncommercial ShareAlike license MOTION OF TRAIN CAR gt HALBACH ARRAY MAGNETIC FIELD LINES CANCEL ORIENTATION OF MAGNET AAANAAANARNARAAAANAAANT LEVITATION CIRCUITS Figure 2 3 1 Inductrack technology Reprinted with permission under the Creative Commons Attribution Noncommercial ShareAlike license While not the fastest method of public transportation the maglev system has the potential to be the cleanest The core of maglev technology lies in the type of propulsion Typical rails today are diesel based which use a wheel and axle system powered by a diesel engine coupled with either a mechanical transmission or a d c generator that powers a traction motor Since maglev rails use virtually no form of wheels axles or bearings this eliminates the need for any type of fuel which the traditional rails would need to provide the necessar
112. on buttons in the application and updated every time a displacement is received Starting time calculation and ending at every displacement interval measured 3 0 Research 3 1 Bibliography of Related Work When considering building a magnetic levitation vehicle the group was aware of different projects that have done this project before With transportation through levitation being a very interesting subject there have been numerous attempts to provide a transportation that moves based on magnetic force propulsion 3 1 1 Linear Motor for Maglev Train 1997 W Beaty One of the most famous ideas is that of science hobbyist William Beaty His design of the magnetic levitation vehicle is based on hall sensors and a circuit consisting of transistors and diodes Each sensor controls the polarity of each electromagnetic coil and vice versa the coils affecting each sensor The sensors reverse the polarity of the magnet when it changes thus creating a zero magnetic field The point is that this will allow superconductive levitation where the coil assemblies repel bar magnets regardless of polarity William Beaty also writes about how one can add an electrical drive motor to the magnetic levitation vehicle The linear DC motors are composed of three parts e Along magnetic track e Amoving coil e A commuter to reverse the poles of the coil The key is to apply sideways thrust to the vehicle by switching polarity on the coils The next sys
113. onnect Thread Class is a thread that will allow both devices to establish a connection and begin exchanging information In order for this connection to be made a server and client must be established where one device opens a server socket and the other device initiates the connection by using specific information about the other device So the server will hold the Bluetooth socket open and listen for a request from the client and accept the request upon getting the connection request In this formation the ConnectThread class serves or behaves as the client InStream Handles the information coming in through the socket OutStream Handle the broadcasting going out of the socket ConnectThread construct Declares the socket and streams for the connection through which data will be transmitted public ConnectedThread BluetoothSocket socket mmSocket socket InputStream tmpiIn null OutputStream tmpOut null Get input output streams using temp objects EPY tmpIn socket getInputStream tmpOut socket getOutputStream catch IOException e mmInStream tmpIn mmOutStream tmpOut Write byte method sends data through this socket Along write is also a Get byte method that gets the information coming through the server socket This is where the commands will be sent to the vehicle and data or information on the vehicles location on the track will be received Called from the main activity to send d
114. ooth controller Since neither the RN 42 nor the RN 52 will fail to meet basic requirements such as dimensions or functionality we have to look into costs and ease of use The RN 42 costs 15 while the RN 52 is reaching upward towards 25 This means that we could save 10 using the RN 42 That being said the RN 52 has much more documentation on use and setup Also the setup seems to be much simpler and will be more effective Since our group is only saving a total of 10 by using the RN 42 it seems as though it is worth it to reach for the RN 52 instead The effectiveness of the RN 52 seems to be superior to the RN 42 enough for us to choose the RN 52 3 2 2 Application Development Application development plays a key role in this project since the application will be the main interface between the user and the system as a whole There is the option of doing an application for a MAC laptop or a Windows 8 Operating System laptop There is also the option of developing a smartphone application for a cellular device or developing a web application Given that a smartphone is a more feasible and portable device not to mention the growing popularity of its expanding capabilities the application was to be developed on a smartphone There was the option of diving into the field of application development in either of the two leading smartphone producers of our generation which includes the Android and the iPhone One of our group members had develop
115. oped in the Android application Bluetooth Adapter Bluetooth Device Bluetooth Socket Bluetooth Server Socket Bluetooth Class Bluetooth Profile For the application to be able to use the features of this library at least one of the two Bluetooth permissions needs to be declared Bluetooth and Bluetooth_Admin The Bluetooth permission is used for connection purposes such as requesting and accepting a connection as well as transferring data through the connection Bluetooth_Admin must be declared in order to manipulate the settings for Bluetooth that are already incorporated in the smartphone device Through this permission the application can put the device in device discovery mode This mode will actually allow the smartphone to search for as well as be found by any Bluetooth enabled devices within the probable range After filtering the main functionalities of the application a user interface needs to be designed to integrate these functionalities The application s interface is designed using XML Extensible markup Language and the Android Development Tools downloaded for the Eclipse Environment These tools allows developers to design the interface of the application by either simply dragging and dropping using the cursor and changing widget displays by using the side menus or by editing the actual XML code behind the interface By manually dragging and dropping etc the XML code gets edited simultaneously and accordingly to the chang
116. organized and more subjective view of the system as a whole which will help in the coding and debugging processes that will be undertaken by the group 4 5 3 Client Server The microcontroller in this case will serve as the Server and share its service with the Central client which will be the Android smartphone The Android application and microcontroller will both be configured as such The Central here is the Client or the Android smartphone and the peripheral or external device is the Atmel Atmega Arduino Uno board with the Bluetooth enabled module Figure 4 5 3 shows a Client Server model and the bidirectional relationship between both In the client server model there is a centralized system and therefore when a server has many clients it needs plenty of resources to allocate between each client This is the high level view of the client server model Within the application itself a client server model is also simulated between threads and the main thread where the main thread shares its memory between all other clients or child processes but each individual thread gets its personal memory 94 Client Server Model Central Android Device Figure 4 5 3 Client Server Model The smartphone client will not share any of its resources with the microcontroller in turn it will only send and receive pertinent information The client or smartphone will always initiate communication by scanning a range of its surroundings for any
117. ortance This means that the MCU we choose must have readily available programming software Along with it being available it should be cost efficient and usable by the group members The Atmega328 has been designed to use work with the Arduino IDE v1 0 x which is available free at http arduino cc hu Main Software Since this is free and easily downloadable it meets our requirements for accessibility Unfortunately none of the group members have used the software so we would have to learn Since the group has already used MSP430 we are well aware that code composer studio on campus is readily available Along with it being readily available we all have used it in previous classes so therefore can expect to understand all of the features Memory usage Knowing which memory can be used and how much is available is a feature we also must consider for choosing which microcontroller unit to choose The ATmega328 has its memory listed as e 32KB of flash memory e 2KB static RAM e 1KB EEPROM There are multiple msp430 models for choice up to e 64KB of flash memory e 10KB static RAM e 8KB EEPROM Obviously we do not have such high memory expectations but when finalizing our choice for which MCU s it s good to know what available Documentation The documents available for each microcontroller are useful for reference material on understanding how it works If there isn t very much documentation for a product then our abil
118. ost of all of the preliminary materials building expenses and extra materials that may be needed during the construction of the vehicle For the vehicle only 4 neodymium permanent magnets are needed Their cost is included in the initial budget allocation The financing for the vehicle will be taken care of by the group members themselves The distributors contacted for the vehicle parts are Lowes Home Depot eBay K amp J Magnetics INC 115 For the drive assembly the solenoids are made of wound copper wire with an iron tube for the core The cost of the drive system is included in the initial budget allocation of 100 00 In summary the budget for the vehicle is in the area of 100 00 7 2 3 Miscellaneous budget and financing The last part of the budget distribution falls under the miscellaneous category This section of the budget is comprised of MCU Arduino Uno and Protoshield EM detection Hall effect sensors Power source 9V rechargeable battery Charger for 9V battery Wireless connectivity Bluetooth module Other items TI SN755410 H driver Breadboard Capacitors and resistors The miscellaneous section of the budget was created to facilitate the expenses of all of the additional components that are essential to the project The bulk of this portion of the budget is focused on the MCU The Arduino Uno board is the brain of the project while the Protoshield allows for the design of custom circuits to help the proj
119. other Since they are pulling towards each other in the diagram above we will witness the maglev vehicle stopping Figure 4 1 1 4f double sided diagram With each of these switch organizations only one side of the Solenoid and track were shown As we know all magnets are oriented NS or SN which means the other side of the track needed to be shown The figure above shows the top view of the solenoid to track relationship We can see the dotted line separating what was shown and what was not The magnet in the middle is the solenoid which is two sided Since the opposite sides of the track have opposite polarities the forces remain pushing the cart in the same direction 4 2 1 5 Bidirectional vehicle One of the signals that can be sent from the Bluetooth controller is to drive the opposite direction This means that the same process will happen just in reverse All of the measurements will occur in the exact same way but the timing on when the solenoid is changing will change If we simply run the system in reverse and account for distance calibrations we should be successfully able to move our car backward If anything changes it will be the programming code that is running The connections and signals will still function exactly as they did before the only difference will be the MCU s programing to change the switches Instead of being SN when it there is an S polarized magnet behind and N in front It will be NS in order for the
120. ough magnetic polarity and maneuvering the solenoids through some sensors to achieve propulsion or movement about a track The group decided to take all these ideas together and add its own features as well as approaching certain sections differently by using some of the latest technological updates 3 2 1 Microcontrollers and Boards We decided our design would need a microcontroller The microcontroller s ability to obtain information and control our car via wireless control is an integral feature Our group decided we would need We had multiple requirements and many microcontrollers to choose from We had to consider which features offered by each of these Microcontrollers in order to decide which one to use First we chose features that we knew would be a requirement for the project then we compared that to the microcontrollers we had available Microcontroller Requirements and Preferences e Input output ports and pins e RF radio Bluetooth 16 Brand each group member feels works best Architecture Dimensions Optimal Cost Analog digital converter if needed Voltage and current usage Programming language requirements Compiler program availability Compiler versatility Memory Usage ROM EPROM EEROM Flash Frequency requirements Ease of use Documentation Once we understood what we needed our microcontroller to do we looked into multiple Microcontroller units to see which one would fit our needs the best One of
121. our Buttons used to send motion commands to MCU s Forward sends 1 Back sends 2 Stop sends 3 Speed of vehicle displayed and continously updated Miles per hour inches per second Figure 2 3 3 2 Controlling Interface Speed will be calculated by repeatedly prompting the Bluetooth module on the microcontroller for the vehicles location on the track and using the measured time on the smartphone thus allowing the team to use the displacement divided by time and giving our velocity v As At With the microcontroller keeping track of the location of the vehicle in reference to the track and the smartphone keeping track of the time the team will be able to calculate the speed of the vehicle during its movement about the track These variables will begin to get calculated as soon as a directional motion button Forward Back is pressed and will cease to calculate when the velocity reaches 0 mph or when the vehicle s displacement is equal to zero The microcontroller will have preprogrammed dimensions of the track The displacement will be calculated in accordance to the magnets and their specific location on the track The magnets will be about an inch in length Every time the vehicle crosses a magnet the displacement will be updated to the microcontroller This information 13 will in turn be sent to the Android application for processing of speed The time will then be measured from initial touch of the moti
122. pinion The features or a specification that would have the greatest impact on the group s system is the Bluetooth capabilities and the processor speed Looking at each smartphone s Bluetooth capabilities it can be 31 seen that all of the smartphones bring forth the latest version of Bluetooth which is Bluetooth 4 0 LE Low Energy So now it was a matter of the processor speed as the processor would play a role in the user responsiveness and processing of the sending and retrieving data Although the Samsung Galaxy S4 had the fastest processor the others were not too far behind The matter came into really just choosing individual preferences as mentioned earlier The outcome was the Samsung Galaxy S4 which dealt mostly on those extra two or three hundred Hertz of processing power 3 2 0 Wireless Communication Wireless communication is a growing field with more and more technologies available for this form of communication including infrared Wi Fi Bluetooth and other relevant technologies For the magnetic levitation system that the group proposes to design two of these technologies are the most prominent and best suited for this type of system These are both Wi Fi and Bluetooth Wireless Communication Both of these technologies provide an ample medium through which the remote controller and the system can communicate 3 2 3 1 Wi Fi Connectivity Wi Fi is a wireless communication standard that uses radio frequencies to establish
123. put from the 75 device and all we have to do is the value to a variable of our choice The code will save the current input as a variable and begin testing The device will be sending one of four signals Brake speed 1 speed 2 speed 3 Speed 1 2 and 3 will all lead to the same core function of moving the cart The only thing that will be different is the speeds at which the magnets are changing causing the vehicle to move If it receives a brake signal it will cause the MCU to perform the functions it needs to in order to stop the vehicle Once the controller takes the signal it can begin functioning throughout the rest of the code 4 2 1 2 Taking the Hall effect Input Once the MCU has received an order from the Bluetooth device the next step is taking the Hall Effect input Taking the Hall Effect input is the first step of the movement process of the Maglev vehicle Without this step our vehicle would be unable to determine where it is in relation to the magnets on the track and therefore wouldn t be able to accurately move itself in the expected direction Also our car will be controlling the solenoid magnets based on whether the solenoid is next to a N or S polarized magnet Using this information it will be able to determine the pattern it will change its own solenoids In order to function the Atmega328 to receive the input from Allegro A1301 we will have to make sure the ports are established correctly We will have three Hall
124. r magnets Arduino Board housing a i magnets glued to underside m l I Eng Figure 4 1 4 2 Top view of 2 car Prototype Final Car Design The final design for the vehicle consisted of one piece of hardwood 5 5 x 5 with ten magnets glued to the topside of the vehicle for stability purposes 5 on each side The aluminum C channel ran the length of the vehicle 5 5 and is wide A 2 wood extension was needed between the main platform and channel in order to correctly place the channel within the drive shaft so that the electromagnets could properly interact with the permanent magnets Our DOT PCB was mounted on the topside of the vehicle which held all of our electrical components 4 1 5 Car Materials There are three major components for the car design e Wood foundation e Aluminum channel e PCB Microcontroller housing 72 The aluminum channel houses the solenoids and the wiring to and from the Arduino PCB located on top of the car The housing for the PCB and microcontroller for aesthetic reasons will be comprised of Plexiglass This will display the LED s on top of the PCB more clearly to indicate electromagnet polarity Non ferrous screws are ideal for construction as to not interfere with the car or track magnets A strong epoxy adhesive is needed for attaching the magnets to the underside of the car otherwise safety could be a concern when adjacent magnets come within proximity of
125. range use this method of interaction any unlikely interference will at most last but a fraction of a second To further isolate our system Bluetooth allows detection for individual or certain addresses thus when our remote smartphone and our vehicle are in range they form a small network So in the case that another device is in range and transmitting a Bluetooth signal our system will ignore this interference being that it will not be within our systems network Other choices of wireless connectivity include Wi Fi yet the reason our system will communicate via Bluetooth is mainly due to low cost and bit rate Wi Fi allows a faster connectivity yet when it comes to communicating Bluetooth has Bit Rates of about 2 1 Mbps while Wi Fi is in the range of 600 Mbps A comparison chart between Bluetooth connectivity and Wi Fi connectivity can be seen in table 4 to further emphasize the differences between each technology 33 Comparison chart Bluetooth vs Wi Fi BLUETOOTH WI FI Frequency 2 4 GHz 2 4 3 6 5 GHz Standard IEEE 802 15 IEEE802 11 Cost Low High Bandwidth 800 Kbps 11 Mbps Specifications Authority Bluetooth SIG IEEE WECA Security It is less secure It is more secure Year of development 1994 1991 Primary Devices Mobile phones mouse keyboards office and industrial automation devices Notebook computers desktop computers servers TV Latest mobiles
126. re 3 3 2 1 Diagram displaying LSM propulsion Figure 3 4 Interaction between sensors and track magnets Figure 3 5 Three Phase sinusoidal wave diagram Figure 3 5 4 Sample test cases for the drive system 108 109 110 111 112 113 113 115 115 115 116 116 117 118 119 120 Figure 4 1 Rough sketch of straight track 56 Figure 4 2 Initial circular track design 57 Figure 4 3 The rough sketch of the track 58 Figure 4 4 The arc dimensions shown 59 Figure 4 5 Straightaway dimensions shown 59 Figure 4 5 1 Magnetic field of a rectangular magnet 63 Figure 4 6 Magnetic calculator 64 Figure 4 7 Rough sketch of the passive coils 65 Figure 4 8 A halbach array using neodymium magnets 66 Figure 4 9 The cutout view of a prototype track design 67 Figure 5 0 The side view cutout of the track 68 Figure 5 1 A mock representation of the Team Antipodes 68 Figure 4 1 4 1 Top view of 1 car Prototype 71 Figure 4 1 4 2 Top view of 2 car Prototype 72 Figure 4 2 1 1 Bluetooth Block diagram 75 Figure 4 2 1 2 Hall effect Block diagram 76 Figure 5 1 1 4 1 Switch signal block diagram 79 Figure 5 1 1 4 2 NS magnet block diagram 81 Figure 5 1 1 4 38 SN magnet block diagram 82 Figure 5 1 1 4 4 No magnet block diagram 83 Figure 5 1 1 4 5 Aligned Magnet block diagram 84 Figure 5 1 1 4 6 double sided diagram 85 Figure 4 4 1 Class Diagram Maglev Controller 87 Figure 4 4 1 1 Class Dia
127. re PCB 2 Stackable Headers 8 pin 2 Stackable Headers 6 pin 2 5mm LEDs 2 330 Ohm resistors 1 10k Ohm resistor 2 push buttons 2 1 uF ceramic capacitors The capacitors of the kit will be placed across the 5V supply and ground acting like decoupling capacitors to prevent unwanted voltage change to the board All the components are soldered through hole and tutorials for setup of this protoshield kit are provided on SparkFun com The interesting components to comment about in this kit are the 5mm LED s These LED s could serve a number of purposes for our project One of the LED s could be used as a power indicator connected directly to the 5V supply pin on the board The buttons could be useful as well when the need arises to toggle manual control between drivers instead of control solely through the software The ProtoShield as far as our Solenoid driving circuitry should have enough space for our two H bridge drivers and LED s signifying current direction The prototype board even comes with a 6 pin header for our Bluetooth module the important pins being the Rx and Tx for wireless serial communication Final Circuit Design The final circuit did not consist of any development boards Although we did use the Arduino Uno for testing and prototyping our circuit for the final circuit we had an atmega328P for our MCU and utilized the pin connections it has to interface with our h bridges and hall effect se
128. reating a current and therefore creating a magnetic field As long as the Solenoid creates the correct polarity for its magnetic field it will attract and push appropriately If we expect a N polarity and it is being attracted to an N polarity magnet we know that it is not working properly and must change the plan Once we know that the Solenoid is creating the correct magnetic force we can connect to the TI SN754410 Once we connect them together we can test the solenoids magnetic polarity whenever certain digital inputs are applied to its ports The way we plan to accomplish this task is by changing the switches and measure the solenoids magnetic field We will follow and fill out the table below and decide whether or not we have accomplished the task S1 S2 Expected Measured Correct polarity Polarity measurement 0 0 off 0 1 NS 1 0 SN 1 1 off Table 6 3 4 H Bridge Control Test Table If we fill this table out successfully then we know this section of the design is complete 109 6 3 5 Testing Atmega328 Output to H Bridge Circuit In order to efficiently test the signals being sent from the MCU to the H bridge circuit we will simply use a multi meter to read the signal being sent out of each of the digital outputs we are using We will instruct the MCU to send signals using the code of our choice and it will end with us being able to measure the amperage of each wire If we successfully
129. red the team now looked into the Android Operating System and its application development 3 2 2 2 Android Development Developing for the Android OS is a completely different scenario As far as the tools and environment Android allows you to use just about any Operating System which means any laptop can be used as a viable tool to develop an Android application This was the first obstacle faced with iOS development The next step is to choose an Integrated Development Environment When it comes to Android the team had more than one choice with IntelliJ and Eclipse being the most probable choices Since the team was familiar with the Eclipse Environment and the Android Developers site suggested Eclipse that s what the team chose The Android SDK also came with an emulator that would simulate the android OS on the computer used for development In order to start developing an Android app a version of Eclipse was needed and then the team was to download the Android SDK Software Development Kit After this the ADT Android Development Tools for Eclipse needs to be installed and the latest SDK tools and platforms are to be downloaded using the SDK manager already installed with the ADT All of these steps are seem simple and more familiar since Eclipse is an IDE the team was familiar with Java vs Xcode The main programming language that will be used is Java and as mentioned earlier this is a technology the team had experience with in con
130. ring with the linear motor placed on the vehicle Creating a Halbach array with electromagnets proves problematic as we have less space to work with The electromagnets need to be sufficient in size to generate the necessary lift to support the weight of the car 45 5 5 Lye L z ZA Figure 3 2 A simple electromagnet consisting of wire wrapped around an iron core Note the magnetic field lines BL and fringing fields BF Reprinted with permission under the author s Chris Burks written consent Taking both of these choices into consideration we decided to use the neodymium permanent magnets to generate levitation By using the neodymium magnets we have much more space to deal with as these magnets run quite small We also eliminate the need for a feedback loop as the permanent magnets are passive By equipping the car with identical magnets we can achieve lift quite easily by repelling the magnetic fields We don t need to constantly monitor the permanent magnets like we would need to with the electromagnets 3 3 2 Lifting Power The magnetic force is created by the current passing through the wire In order to achieve levitation of our vehicle the magnetic force must overcome gravitational force so that H Fg approximately Levitation is similar to the statics theory of achieving equilibrium The ideal system will be frictionless but achieving that result will in effort be challenging An
131. s of the Atmega328 outputs we have changed the direction of the current and therefore changing the polarity of the magnet This back and forth pattern will lead us to moving correctly along the track When solenoid is aligned with a track magnet either S or N Below we have a diagram showing the switch signal values when the solenoid is aligned with the track Figure 4 1 1 4d No magnet block diagram The figure above shows the switch orientation whenever the magnet is aligned with a track magnet Since there is no perfect way to pull or push in the correct 82 direction when directly aligned we need to turn off the magnet and let the other magnets do the work during this phase Since we will have each solenoid functioning along with each combination the aligned magnets will not have to be creating any force and the other solenoids will be able to move successfully Brake signal Below we have a diagram of the switch signals when the MCU has received a signal to stop the system Figure 4 1 1 4e Aligned Magnet block diagram Whenever we receive a signal of brake from the Bluetooth controller we need to set the solenoids polarity to whichever magnet is closest to it For example 83 above we have received the brake command and our magnet is aligned with an N magnet This means that we will change the H Bridge circuits switches to cause the solenoid to be S polarized so that they will pull towards each
132. s is a constant of type integer which will represent the command to move the vehicle in the forward direction e Back This is a constant of type integer which will represent the command to move the vehicle in the backwards direction e Stop This is a constant of type integer which will represent the command to brake or stop the vehicle when it is moving in either direction e Distance This is a variable of type integer that will be measured in centimeters e moveFoward method This method will handle the command sent to the vehicle to move it in the forward direction It will send the Forward constant of 1 through 3 that will be received by the microcontroller e moveBack method This method will handle the command sent to the vehicle to move it in the backwards direction It will send the Back constant of 4 to 6 that will be received by the microcontroller e stopVehicle method This method will handle the command sent to the vehicle to stop its motion in either direction It will send the Stop constant of 0 that will be received by the microcontroller e getDistance method This method will continuously query the server to update the distance traveled by the vehicle during any point in time and will be called and return to the displaySpeed method e dispalySpeed method This method will handle the speed calculation of the vehicle and will be updated continuously during the vehicles path about the track 89 ConnectThread Class The C
133. sensors will be oriented on the car to send a three phase voltage signal back to the MCU This means that each linear voltage waveform for the sensors will be 120 degrees apart from one another as shown in Figure 3 5 The phases for each of the waveforms in Figure 3 5 correspond to the three Hall effect sensors The scale that is shown will also be adjusted having the 0 point be 2 5V ranging from OV to 5V on the Y axis This is another reason why linear hall effect sensors are important for the team s drive system Having a three phase linear voltage reading allows for precise speed control by timed shut off and turn on of each one of the solenoids along with alternating the polarity of the solenoids to the correct polarity of the upcoming track magnet Each one of the solenoids will operate as such in the following cases highlighted for the N pole magnets but will work similarly to when interacting with an S pole magnet 3 5 1 Approaching N Pole B magnet When approaching an N Pole magnet which gives a negative value magnetic field the sensors will output a decreasing voltage from 2 5V OV Within these voltage ranges the solenoid connected to that sensor will have an S N orientation until the value is close to OV 49 3 5 2 Perpendicular to N Pole B magnet Once the output voltage from the sensor is near OV the respective solenoid will be turned off This threshold voltage that needs to be crossed will have to be determined by tria
134. space will space out the magnetic field while too little space could convolute the magnetic fields With these track designs in mind the group decided to go with the Inductrack EDS hybrid This design was the most feasible in terms of achieving what was desired out of the project and had the least amount of setbacks Cost will always be an issue but for the hybrid design it is not a big enough issue to break the design outright Design procedure Track structure With the basis for design chosen the group then started the debate on what kind of track structure would be ideal to showcase maglev technology There were a few factors to consider when choosing a structure e A structure that would facilitate high speeds e A structure that would not inhibit vehicle movement With this criterion the group turned to the current maglev rails in operation today for ideas on proper track design Upon investigating the rails the main difference between the maglev rails and the wheel axle rails is the type of propulsion used In essence the rails are the same in terms of the type of structure and shape 54 With modern railway systems as reference the group set out to decide if the track was to be a straight track or a circular track There were advantages and disadvantages with both track designs Straight track advantages e Simple construction e Showcases linear motion both forward and backwards Straight track disadvantages e A fin
135. t from the smartphone controller to the microcontroller such as long words of type strings 96 Those are the main commands that will be sent to the vehicle through the microcontroller The microcontroller will in turn be programmed to receive those commands and act upon them based on each unique command The last information exchanged between the android smartphone remote controller and the microcontroller is the distance travelled by the vehicle This will be an Ongoing request by the android smartphone on the microcontroller So the microcontroller will have to consistently know the position of the vehicle on the track By querying the Arduino Uno R3 microcontroller every quarter of a second or so the android smartphone can in turn use the information of distance travelled and calculate as well as consistently update and display the speed of vehicle Final Project In the final project we were not able to do variable speeds instead we had only One constant speed This was due to the short length of the track and choice of digital outputs for the H Bridges 5 0 PCB Circuit Design 5 1 Arduino Interfacing This section will detail the connections of the various components used in driving the solenoids and position sensing 5 1 1 Interfacing A1301 with the Arduino Board The Hall effect sensors will utilize three of the analog inputs on the Arduino Uno R3 board Resistors are connected between the output of the sensors and the board to
136. tem involving related work is heavily based on William Beaty s article and work done 3 1 2 Antipodes Magnetic Levitation Vehicle This design is a remote controlled 3 phase 6 solenoid motor with electromagnetic propulsion system done by an FTC World Championship team This system was built and designed by the team and based on William Betty s 14 1994 article mentioned above This team had two parts to their electronic system consisting of the motor controller and the remote The remote is an Xbee antenna mounted on an Arduino Prototyping shield which is mounted to the Arduino Uno R3 microcontroller and powered by a 9 V battery An encoder is also mounted and used for the users input The motor controller carriers an Xbee antenna mounted on an Arduino Prototyping shield as well They in turn have two Sparkfun Ardumoto Shields which are mounted on a separate Arduino Uno R3 and powered by an 11 1 V Lithium Polymer battery The motor shields in this project are used for sending current to the vehicle in either direction The three Hall effect sensors provide the three phase system and give measurements to the controller The track is made of wood and Plexiglas and of course different magnets and spacers to go in between magnets in a Hall Bach array like manner Their vehicle is composed of Lego parts and some aluminum material Communication and propulsion is done through the Hall Effect Sensors where the microcontroller is programmed
137. the Microcontrollers we selected was the Arduino Uno Revision 3 board which uses an ATmega328 microcontroller Another Microcontroller and board we were looking at was the MSP430 Input Output For our microcontroller the amount of inputs and outputs available is a big deal In this case we have to make sure our microcontroller will be able to handle the number of inputs and outputs our project requires When looking into the Atmega328 we can find that the there are 14 digital Input output pins and 6 analog Input Outputs We can see that on the msp430 there are 6 digital I O ports each of these ports supporting 8 digital I O pins As we can see here the msp430 wins out having the larger number of possible inputs since our project doesn t seem to need analog ports for basic function RF Radio or Bluetooth Obviously none of the microcontrollers were going to have an integrated wireless communication function already on board but this was still a call for concern since we knew our project would be controlled wirelessly Since we knew this is a requirement for our project we wanted to make sure there was a popular piece of hardware that was configurable with the current model of MCU we choose For the msp430 and the ATmega328 we have the very popular RN 42 Since both are compatible the only distinguishable feature is the amount of information on configurations and programming 17 Brand Obviously brand is going to be a consideratio
138. the current is presently flowing through the solenoid This will translate to the direction the vehicle is moving on the track This requires a total of six 98 LED s two for each solenoid separated into two colors three green and three red A capacitor will be placed between Vin and ground in order to prevent the microcontroller from resetting right away when power is disconnected Another important schematic feature to look at in Figure 5 1 2 is that the enable pins for the three solenoids are connected to the Digital I O pins on the Arduino board instead of connecting the enables to the 5V supply pin This could be useful when controlling the functionality of the solenoids With the enables connected directly to the 5V supply there are only two options of movement left or right front or back depending on reference position Now with the enables connected to the Digital I O pin the current drivers could be shut off completely The total modes of operation are now three forward back and off Solenoid ARAN J po iW g4 Vi J x NAY 5 x p ARDUINO it i Figure 5 1 2 Connections between the Arduino H Bridge drivers and Solenoids 99 5 1 3 Interfacing Bluetooth with the Arduino Having the Bluetooth module will eliminate the need for serial cables to
139. ther conductive material or magnets Our EMS design took a slightly different approach to creating the necessary propulsion Instead of fitting the vehicle with electromagnets we designed the track to have electromagnets on the sides while the vehicle was fitted with permanent magnets These electromagnets would be interfaced with optical sensors that would be able to detect the presence of the vehicle when it was approaching This way the next electromagnet would turn on while the previous electromagnet would turn off This design was based off of an older senior design project where the group created a maglev vehicle that used optical sensors with electromagnets While this design looked great on paper it had its flaws e Manual labor intensive e Cost e Additional components e Unsure if the design met what the group wanted to achieve This design is very labor intensive It was decided that the amount of manual labor overshadowed the amount of engineering design that was desired to experience The cost of the track would be very high as this system was also analog Another decision that was needed to be made was if a control system was necessary to keep the vehicle afloat or if permanent magnets would suffice Most EMS systems make use of a feedback control system to keep the vehicle stabilized vertically and horizontally by monitoring the current in the electromagnets After taking into account the manual labor cost and the availabilit
140. timeter XMM1 z F coe 1 758 UA 1 m GS a w EE Cao G 7 ee I 1 i Figure 3 2 6 2 Scenario 2 S2 high and S1 Low gt current right to left through load 3 2 7 H Bridge IC Doing a search online found a number of possible choices for IC s TI supplies IC s that will be ideal for our applications The DRV8837 is a low voltage single H Bridge IC it has the following specifications Specifications 1 8 11V operating supply voltage 1 8 A max drive current PWM interface Drives a single winding of a solenoid The current and voltage ratings are within our usable ranges The only drawback of this IC would be that in order to drive the three windings of our solenoids we would need three of these chips So we must consider instead buying a three phase H Bridge IC to drive the three solenoids Tl s L293D are quadruple high current half H drivers with the following operating specs 38 Specifications 4 5V 36V supply voltage range 1A output current per driver 2A peak 3 state outputs Output diodes to suppress Inductive transient response High Noise Immunity Inputs The L293D can drive two solenoids in either direction The operating voltage range is much higher than the previously discussed DRV8837 but within the range of what our power source can supply roughly 9 12 V 3 2 7 1 TI SN754410 This H Bridge IC is very similar to the L293D e
141. ting with a microcontroller device The remote controller not only has to be able to send inputs or commands to the microcontroller but receive an input from the device to monitor the speed of our vehicle Speed is a parameter that will be available on the remote controller thus forcing the remote to have this functionality So the remote controller has to have the capacity or ability to establish a wireless connection between the system and the remote itself send and receive inputs through this network and have the capabilities to monitor the speed of the vehicle in real time The remote controller will need access to a real time clock giving us a time parameter for the calculation in velocity The other parameter of displacement can be calculated by the controlling system of the magnetic levitation vehicle and sent as an input to the remote controller In whole the required functionalities of the remote that will control the magnetic levitation vehicle are as follows Able to send and receive data Have wireless communication capacity Ability to interface with a controlling circuit or microcontroller Have a user interface that will display information Store data in real time Wireless capacity range of 10 feet minimum For this project there were several choices of how to control the magnetic levitation vehicle Three options were brought forth the first being an analog remote controller which had been used previously by other teams w
142. tored setting 115K ON 9600 Table 3 2 1 2b Switch and Pin Setup Once we have the RN 42 configured and ready to operate we simply have to list a few commands using the list found in the user manual in order to operate appropriately in the system Also knowing which of the pins will be connected to which I O of the MCU will be an essential part of the Maglev control Figure 3 2 1 2b Pin Diagram reprinted with permission from www mbed org 22 The transmitter will easily have enough range to control the maglev The data sheet says 55 ft after one wall and because we never plan on being between a wall or more than roughly 10 feet away our design should be able to work perfectly 3 2 1 3 RN 52 The other popular device we have available for wireless communication is the RN 52 This is obviously the later version of the previously described RN 42 Since were looking for the most efficient part we could be using for this project we needed to do research on this part This device will be used to connect to Bluetooth as required by the project GENERAL SPECIFICATIONS Specification Description Standard Bluetooth 3 0 class 2 Frequency Band 2 4 2 48 GHz Modulation Method GFSK PI 4 DQPSK 8 DPSK Maximum Data Rate 3 Mbps RF Input Impedance 50 ohms Interface UART GPIO AlO USB SPI speaker microphone Operation Range 10 meters 33 feet Sensitivity 85 dBm at 0 1 BER RF TX Power 4 dBm WEIGHT amp DIMENSIONS
143. trast with a brand new IDE and programming language such as Xcode and Objective C Both of Java and Xcode provide the use of Object Oriented programming design Java however is more of a class based language which allows for more organized programming Objective C is an extension of the C language with what they call smalltalk Smalltalk gives the use to objects to e Hold state references to other objects e Receive a message from itself or another object e In the course of processing a message send messages to itself or another object This implementation of objects is also available in Java Although Java does derive many of its syntax from C it brings a completely different programming 28 language being designed to have as few implementation dependencies as possible References for the Project As far as source code examples and interfacing the Android smartphone with external devices such as in our case a microcontroller this was a definite plus Plenty of examples and guides were found that would help our development in the Android OS In contrast to iPhone and Apple Google the maker of the Android smartphone actually has numerous tutorials on interfacing with different external devices and accessing the Bluetooth capabilities of the phone This is important to our system since we will be able to gather information and have a better picture of the interaction that will happen between the smartphone and the microcontroll
144. travel times The Shanghai maglev system has a top speed of 431 km h 268 mph and has reached a record speed of 501 km h 311 mph 3 In Japan the experimental JR Maglev system broke the world record for trains at a speed of 581 km h 361 mph As far as travel speeds go the only method of travel faster than the above mentioned systems is air travel If maglev rail systems are implemented in high population areas travel efficiency can only improve Figure 2 4 The JR Maglev design The JR Maglev uses EDS technology to achieve its break neck speeds This design uses wheels at low speeds as the flux at these speeds cannot hold the weight of the train Reprinted with permission under the Creative Common Attribution Noncommercial ShareAlike license Another motivating factor of this project is that maglev technology is clean technology As stated above the conventional rail systems use fuel based diesel propulsion which in turn creates emissions Environmentally these emissions are not ideal This is where maglev technology shines Since the entire concept of maglev revolves around magnetic fields and electricity there is no need for any sort of fuel combustion or compression to generate energy to power the train By eliminating the need for fuel the potential of generating emissions is virtually eliminated A third motivating factor in choosing this project is to demonstrate the workings of the maglev system and how easy maintenan
145. tween our remote and our system will allow for as minimal interruption as possible given the technological advances today using a communication frequency between 2 402 GHz and 2 480 GHz which has been set aside by international agreement for the use of industrial scientific and medical devices ISM Our smartphone will send out a small signal of about 1 milliwatt limiting the range of connection between our remote and vehicle to about 10 meters or 32 feet This will further limit the odds of other devices in the area of testing or presentation that might have the ability to interfere with our system and device yet it is also a good enough range to where the user will not have to be directly next to the system more specifically our magnetic levitation vehicle Since our vehicle will be moving about a circular track with a radius of 0 75 feet the range in our Bluetooth connection will allow a sufficient testing distance In the case where there might be other devices such as other smartphones which will be likely with a Bluetooth capacity the Bluetooth connection uses spread spectrum frequency hopping This approach will isolate our system from any external devices since our connection will use about 79 discrete and randomly chosen frequencies within a chosen range and will be switching between these frequencies consistently So our transmitters will change frequencies 1 600 times every second Given that other Bluetooth devices that might be in
146. working properly We will finally be ready to complete the full build of the vehicle and test the prototype 6 3 7 Final prototype testing For the final prototype test we will figure out if or device works and meets all of our standards This test will be a simple checklist for the maglev vehicle to complete in order to determine all parts are satisfied This final prototype test could be done anywhere as long as we have the full vehicle and track there will not be any excessive equipment for this test The checklist will be set up simply as the maglev vehicle being able to complete each command sent by the Bluetooth controller The Table below will be our simple checklist we need to complete Task Complete Y N Speed 1 forward Speed 2 forward Speed 3 forward Speed 1 backward Speed 2 backward Speed 3 backward Brake Table 6 3 7 Prototype Test Table The way we know that we have accomplished all of our goals breaks down to if we are able to check off each task above 6 4 Facilities and Equipment This project is very labor intensive and will require much use of the facilities available to the group One of the facilities that will be used is the senior design laboratory which provides electronic instrumentation and software for Senior 111 Design students to create as well as model their projects The project will require the use of this facility for testing buildin
147. xcept that it is sold a dollar cheaper with most online sites Its specs are almost exactly like the L293D Specifications 4 5V 36V supply voltage range 1A output current per driver 3 state outputs Half H and Full H solenoid drivers Diode clamped inputs This IC is listed as an improved functional replacement of the L293 Like all the other H bridges it drives inductive loads such as our solenoids Figure 3 2 7 has the pin layout of the NE package that we will be purchasing along with an example motor control circuit with flyback diodes Figure 3 2 7 1 has the corresponding functions to each of the pins 39 Control A Control B Figure 3 2 7 Pin layout for the TI SN754410 Pin Function number 1 Enables and disables 1 solenoid 2 Digital logic pin high or low 3 Connects to one of the 1 solenoid wirings 4 Ground 5 Ground 6 Connects to the other wiring of the 1 solenoid 7 Digital logic pin high or low 8 Power supply 9 Enables and disables 2 solenoid 10 Digital logic pin high or low 11 Connects to one of the 2 solenoid wirings 12 Ground 13 Ground 14 Connects to the other wiring of the 2 solenoid 15 Digital logic pin high or low 16 IC power supply 5V Figure 3 2 7 1 Pin Numbers and Functions 40 Cost DRV8837 Free Samples on TI would need 3 L293D 3 08 x 2 6 16 SN75
148. y energy to power the mechanical systems All linear motion is maintained by the magnets either on the track or on the train itself This project will follow the similar idea of the current maglev systems which are commercial rails meant for mass transit The project will demonstrate how linear motion as well as levitation is achieved without the need for wheels bearings axles and fuel Our project will be on a smaller scale which will utilize and demonstrate the fundamental ideas of maglev technology These ideas are a high speed mechanically frictionless method of transportation and a transportation system with an environment friendly method of sustainability By demonstrating these concepts this project will serve as an educational tool as well as a neat way to show the possibilities of how mass transit can change in the future 2 1 Project Motivation and Goals The main motivation behind the maglev project is to show our peers that this technology exists Maglev is for lack of a better term young so to speak As stated above there are only 2 commercial rails in existence at the moment one of which is accused of being a white elephant 2 However the potential for maglev is virtually limitless Conceptually it is an obvious improvement to mass transit worldwide Since the entire technology is based off of a mechanically 4 frictionless method of propulsion there is an obvious increase in speed which leads to a decrease in
149. y friction encountered is negligible since our maglev vehicle will not be achieving speeds to where the friction would be noticeable in calculations 46 Levitation is produced from interaction of similarly arranged polarity magnets The tricky part however comes when arranging the magnets so that the car is stable on the track Linear Synchronous Motor LSM is a term used to describe an array of electromagnets Interaction with the permanent magnets on the vehicle cause linear propulsion The electromagnets are created through a 3 phase copper winding and applying an AC source The alternating current is important because the change in direction corresponds to the polarity shift of the magnetic field This shifting repulsion and attracting generates the desired motion The velocity can be adjusted by changing the frequency of the sinusoidal waveform A higher frequency results in a higher speed and vice versa This is the easiest method to cause the desired linear motion yet it would not have enough design material for a four person project Figure 3 3 2 1 shows how the magnetic fields in the windings propel the vehicle down the track It provides insight on which direction the field lines are oriented and vehicle direction for both the top view and side view of the LSM system If the group decided to go down this approach for the track design LSM Top View Energized LSM Winding In Guideway EEA R Upwards Vehicle Magnetic Propulsion
150. y of the parts that were desired it was decided that this track design while good is not the best for what was desired The next track idea was to follow the EDS system 52 Initial track design Electrodynamic suspension The EDS system is in use in Japan as an experimental track to test the capabilities of the maglev train systems The EDS system uses an array of superconducting magnets on the track and on the train to create lift and propulsion The track and train both emit a very powerful magnetic field due to the caliber of magnets used As explained in the introductory sections it uses the push pull effects of alternating magnetic poles to create propulsion These push pull forces can yield speeds that exceed 500 km h the land speed record for a rail vehicle was set by the JR Maglev in Japan at 581 km h This rail is an EDS system rail Our design would have followed suit with the existing EDS rails with permanent magnets fastened to the car and to the rail However there were obvious limitations to what we could do following an EDS design which led to removing the design completely The EDS system had a multitude of problems that the group faced when deciding if this track design was the proper design for the project Type of magnets Cost Potential health hazards Industrial hazards Speed hazards General non feasibility The EDS system uses super cooled magnets that essentially create superconductors An obvious problem w

Final Documentation - University of Central Florida

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