Navigational Aid for a Blind Individual - PowerPoint Presentation

Navigational Aid for a Blind IndividualElectrical/ Computer Engineering Team P12015: Bob EvansJackson LampDavid SachenikDavid Yip P12016: Curtis Beard Aalyia Shaukat David Taubman Oliver Wing

SummaryIntroduction/ReviewPower CalculationsBatteryUser Input (Keypad)MicrocontrollerNavigation AlgorithmSchematicsMagnetometerRFID Reader/Antenna/TagsTesting ProceduresBill of Materials

Our Navigation Aid Device

P12015: Power Calculations RFID Reader1.5796 W*hr Motors 0.021166667 W*hr MCU 0.047784 W*hr Magnetometer0.0913W*hrKeypad0.083333333W*hr*Sum1.823184W*hr *For (10) 20 minute intervals of navigation Battery is 3.7V, 1000mA* hr , 3.70 W* hr Voltage Output: 3.3V

P12016: Power Calculations Total Power (mW/hr)Total (mW)Battery Life (%) Total hours of Life 23.1495 77.165 1.8959 175.8137 236.8721 789.5738 19.399817.1823737.64702458.823460.41335.5175Battery is 3.7V, 1100mA*hr, 4.01W*hr Voltage Output: 3.3V *For (10) 20 minute intervals of navigation Min Usage ( mAh ) = 23.3833 Min Usage (mWh ) = 77.165 Average ( mAh ) = 239.2648 Average ( mWh ) = 789.5738 Worst Usage (mAh) = 745.098 Worst Case ( mWh ) = 2458.8234

PRT-003393.7 V1000 mAh2.09” x 1.3” x 0.225”0.770 oz2-pin JST-PH connector P12015: Battery

P12016: Battery Tenergy Li-ion 175003.7V1100mAh0.71” x 2.09” (Diameter x Height)1.04 oz.Molex 51021 2-Pin Connector

Comparison of Voltage Regulation output and POK – Threshold Reached Indicator

User Input (Keypad)7 Pin ConnectionContact rating: 20mA, 24VDC2.52” L x 2.01” W x 0.28” H0.26 ounces Output Pin No. Symbol 1 ROW 1 2 ROW 2 3ROW 34ROW 45COL 16COL 27COL 3

Microcontroller SelectionFlow ChartMemory UsageClock SpeedsApprox. Number of Instructions processes for algorithm

Program Flow

Path Finding Algorithm

Path Following Algorithm

/* performs dijkstras algorithm upon the building graph */"dijkstra(graph *g, int start ){ int i,j; bool intree[MAXV]; int distance[MAXV]; int v; int w; int weight; int dist;for (i=1; i<=g->nvertices; i++) {intree[i] = FALSE; distance[i] = MAXINT; parent[i] = -1; } distance[start] = 0; v = start; while (intree[v] == FALSE) { intree[v] = TRUE; for (i=0; i<g->degree[v]; i++) { w = g->edges[v][i].v; weight = g->edges[v][i].weight; if (distance[w] > (distance[v]+weight)) { distance[w] = distance[v]+weight; parent[w] = v; } } v = 1; dist = MAXINT; for (i=1; i<=g->nvertices; i++) if ((intree[i] == FALSE) && (dist > distance[i])) { dist = distance[i]; v = i; } }} Navigation Algorithm

Navigation Algorithm Time Calculation

Mapping Data StructuresRFIDTagRepresentation of an RFID tag. May be implemented as a 64 bit integer. Tags are stored in an array in FLASH and are referenced with an index value .StaticNodeBasic node in a map graph. Composed of multiple RFIDTags, destinations, and references to other Nodes using NodeVectors. StaticNodes are stored in an array FLASH and are referenced with an index value.ElementsnumTags: The number of tags referenced by this Node.tags: The array of RFIDTag indicies referenced by this Node. numDestinations : The number of destinations associated with this Node. destinations: The array of destinations associated with this Node. numNodes: The number of NodeVectors leading to other nodes associated with this Node.nodes: The array of NodeVectors leading to other nodes associated with this Node.

Mapping Data StructuresNodeNodes are used as proxies to the StaticNode structures held in ROM. They consist of an index value which is used to identify the StaticNode they correspond to as well as a “visited” bit which is used by both the path finding and path following algorithms. An array of these is loaded into memory on system startup in an array which mimics the StaticNode array.Elementsnode: The index of the StaticNode this Node represents.visited: The visited status of the node.NodeVector Represents a link from one node to another. Includes heading and distance information, which is used to determine edge costs in the navigation algorithm and to direct the user during the path following stage. Elements node: The index of the Node referenced by this NodeVector . heading: The direction of the referenced node.distance: The distance to the referenced node.

Mapping Data StructuresDestinationStructure representing a destination using an integer identifier and a heading/distance vector .Elementsid: The room number or other identification code of the Destination.heading: The direction of the Destination from the host Node.distance: The distance to the Destination from the host Node.

Mapping Data Structures

Memory Requirement Estimate Tags300 Tag:Node Ratio 2 Avg. Branches:Node 3 Avg. Dest:Node 2 Max Branches in Map 8 Structure Struct Size (b) Extra Size (b) Size (b) Instances in RAM Instances in ROM Size in RAM (B) Size in ROM (B) RFIDTag 64 0 64 0 300 0 2400 StaticNode 48 112 160 0 150 0 3000 Node 16 0 16 1350 0 2700 0 NodeVector 48 0 48 0 900 0 5400 Destination 48   48 0 300 0 1800 Total           2700 12600

MCU SpecsTI MSP430F5438A16-bit ISA25 MHz Clock16 KB SRAM/256 KB FLASH 8 USCI interfaces with support for SPI, I2C, and other serial protocols18 Programmable PWM OutputsExtremely low power operation—1.05 mW to 35 mW active mode, 1.1 μW to 300 μW sleep mode

MagnetometerST Micro ElectronicsLSM303DLH Tilt Compensated Compass Supply Voltage 3.3VCurrent in Operating Mode 0.83mA16-bit data outI2C serial interface

RFID Antenna/Reader/TagsHperLink Wireless 900 MHz 8 dBi Flat Patch Antenna (HG908P) Skytek M9 ModuleAlien Briggs Tag Type ALN-9640 Squiggle Inlay

Block Diagrams/SchematicUSB Interface with MicrocontrollerUSB Transient SuppressorUSB Charging CircuitLinear Regulator KeypadRFID ReaderPWM (Motors)Magnetometer

Testing ProceduresBattery & PCBKeypadMCUMagnetometerRFID Reader

Battery & PCB testingTest Points (TPs) will be placed in the PCB to verify functionality. Voltage of test points will be measured and compared with their theoretical values. When the battery is fully charged, all test points should be within +/- 10% of theoretical value.

Example of a TP Table Test Point (TP)Theoretical Value [V]Measured Value (When battery is fully charged, falls within +/- 10% of theoretical) [V]TP13.7TP23.3

Keypad TestingInput Room Numbers/Destinations -Monitor MCU data collection -Feedback from vibrating motorsPowering on/off

MCU TestingWhen possible, testing is performed while debugging the MCU.Navigation algorithm will be tested in the following cases:Known tag ID and destination supplied; path returned in < 1s. Known tag ID and unknown destination supplied; failure reported in < 1s.Unknown tag ID and known destination supplied; failure reported in < 1s.Interfaces with other devices will be tested individually prior to the code being integrated with the main program.

Magnetometer TestsCorrect indication of Northern Direction -With/Without interference (Different areas within building) -Flat surface vs. Tilted at various angles -Walking motion testData interface with microcontrollerPower consumption testHeat Dissipation

RFID Reader/Antenna TestsAntenna Position/PolarityRead distanceOptimal reading anglesRead TimePower Consumption TestHeat Dissipation

P12015: Bill of Materials TypePart Manufactuer Manufacturer Part # Quantity Unit Price Shipping Cost Total Cost ($) Component 900 MHz 8 dBi Flat Patch Antenna - 4ft SMA Male Connecto L-com Global Connectivity HG908P-SM 1 $54.99 $10.95 $65.94 Component Precision Haptic 10mm Vibration Motor - 15mm Type model 1 Precision Microdrives 310-001 3 $7.56   $22.68 Component Precision Haptic 10mm Vibration Motor - 15mm Type model 2 Precision Microdrives 310-002 2 $7.56   $15.12 Component Pico Vibe 12mm Vibration Motor - 3.4mm Type Precision Microdrives 312-101 1 $6.48 $17.97 $24.45 Component 3D Compass and Accelerometer Carrier with Voltage Regulators Pololu Robotics & Electronics LSM303DLH 1 $19.95   $19.95 Component LSM303DLH Tilt Compensated Compass Chip ST Micro Electronics COM-09757 1 $6.95 3.86 $10.81 Component Polymer Lithium Ion Battery - 1000mAh Sparkfun Electronics PRT-00339 1 $11.95   $11.95 Component 16-Bit Ultra-Low-Power Microcontroller Texas Instruments MSP430F5438A 1 $12.13   $12.13 Component Small Keypad Futurlec Electronics KEYPADSM 1 $2.20 $4.00 $6.20 Component SkyeModule M9 SkyeTek M9 V.080527         Component PCB     1 $300.00   $300.00 Component IC BATT CHRGR LI+ 1CELL MAXIM MAX1555EZK+TCT-ND 2 $2.37   $4.74 Component IC REG LDO 3.3/ADJ 500MA MAXIM MAX1818EUT33+T 2 $3.25   $6.50 Component IC USB FS SERIAL UART FTDI FT232RL 2 $4.50   $9.00 Case Rod, ABS, Beige, 1 In Dia x 1 Ft L Grainger 1ZBU6 1 $8.59   $8.59 Case Case RIT - 1.998 $10.00   $19.98 Total Cost: $538.04

P12016: Bill of Materials

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