Navigational Aid for a Blind Individual

Electrical/ Computer

Engineering Team P12015: Bob EvansJackson LampDavid SachenikDavid Yip

P12016: Curtis BeardAalyia ShaukatDavid TaubmanOliver Wing

Summary

Introduction/Review Power Calculations Battery User Input (Keypad) Microcontroller Navigation Algorithm Schematics Magnetometer RFID Reader/Antenna/Tags Testing Procedures Bill of Materials

Our Navigation Aid Device

P12015: Power Calculations

RFID Reader 1.5796 W*hr

Motors 0.021166667 W*hr

MCU 0.047784 W*hr

Magnetometer 0.0913 W*hr

Keypad 0.083333333 W*hr

*Sum 1.823184 W*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 19.3998 17.1823

737.6470 2458.8234 60.4133 5.5175

Battery 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) = 789.5738Worst Usage

(mAh) = 745.098Worst Case (mWh)

= 2458.8234

PRT-00339 3.7 V 1000 mAh 2.09” x 1.3” x 0.225” 0.770 oz 2-pin JST-PH connector

P12015: Battery

P12016: Battery

Tenergy Li-ion 17500 3.7V 1100mAh 0.71” x 2.09” (Diameter x Height) 1.04 oz. Molex 51021 2-Pin Connector

2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 40

0.5

1

1.5

2

2.5

3

3.5

4

Regulated Output

POK

Battery Voltage [V]

Outp

ut

Volt

age [

V]

Comparison of Voltage Regulation output and POK – Threshold Reached Indicator

User Input (Keypad)

7 Pin Connection Contact rating: 20mA, 24VDC 2.52” L x 2.01” W x 0.28” H 0.26 ounces

Output Pin No.

Symbol

1 ROW 1

2 ROW 2

3 ROW 3

4 ROW 4

5 COL 1

6 COL 2

7 COL 3

Microcontroller Selection

Flow Chart Memory Usage Clock Speeds Approx. 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

Type of instruction Cost in cyclesCost in cycles for an N=1000 graph

pre-reserved 0 0“ 0 0“ 0 0“ 0 0“ 0 0“ 0 0“ 0 0

deref, comp, branch 20 20000index, assign 10 10000index, assign 10 10000index, assign 10 10000

increment 6 6000index, assign 10 10

assign 6 6index, comp, branch 20 20000

index, assign 6 6000

Type of instruction Cost in cyclesCost in cycles for an N=1000 graph

index, deref, comp, branch 26 104000index x2, deref x2, assign 30 120000index x2, deref x2, assign 30 120000

index x2, addition, comp, branch 32 128000index x2, addition, comp 32 128000

index, assign 6 24000increment 6 24000

assign 6 6000assign 6 6000

deref, comp, branch 20 80000index x2, comp x2, bool, branch 38 152000

index, assign 10 40000assign 6 24000

increment 6 24000Total: 1062016 cycles

Mapping Data StructuresRFIDTag Representation 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.

StaticNode Basic 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.

Elements numTags: 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 StructuresNode Nodes 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.

Elements node: 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 StructuresDestination Structure representing a destination

using an integer identifier and a heading/distance vector.

Elements id: 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

Tags 300Tag:Node Ratio 2

Avg. Branches:Node 3Avg. 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 3000Node 16 0 16 1350 0 2700 0

NodeVector 48 0 48 0 900 0 5400Destination 48 48 0 300 0 1800

Total 2700 12600

MCU Specs

TI MSP430F5438A 16-bit ISA 25 MHz Clock 16 KB SRAM/256 KB FLASH 8 USCI interfaces with support for SPI, I2C,

and other serial protocols 18 Programmable PWM Outputs Extremely low power operation—1.05 mW to

35 mW active mode, 1.1 μW to 300 μW sleep mode

Magnetometer

ST Micro ElectronicsLSM303DLH Tilt Compensated Compass Supply Voltage 3.3V Current in Operating Mode 0.83mA 16-bit data out I2C serial interface

RFID Antenna/Reader/Tags

HperLink Wireless 900 MHz 8 dBi Flat Patch Antenna (HG908P)

Skytek M9 Module Alien Briggs Tag Type ALN-9640 Squiggle Inlay

Block Diagrams/Schematic

USB Interface with Microcontroller USB Transient Suppressor USB Charging Circuit Linear Regulator Keypad RFID Reader PWM (Motors) Magnetometer

Testing Procedures

Battery & PCB Keypad MCU Magnetometer RFID Reader

Battery & PCB testing

Test 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]

TP1 3.7

TP2 3.3

Keypad Testing

Input Room Numbers/Destinations-Monitor MCU data collection-Feedback from vibrating motors

Powering on/off

MCU Testing

When 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 Tests

Correct indication of Northern Direction-With/Without interference(Different areas within building)-Flat surface vs. Tilted at various

angles-Walking motion test

Data interface with microcontroller Power consumption test Heat Dissipation

RFID Reader/Antenna Tests

Antenna Position/Polarity Read distance Optimal reading angles Read Time Power Consumption Test Heat Dissipation

P12015: Bill of MaterialsType Part Manufactuer

Manufacturer Part # Quantity Unit Price Shipping Cost Total Cost ($)

Component900 MHz 8 dBi Flat Patch Antenna - 4ft SMA Male Connecto

L-com Global Connectivity HG908P-SM 1 $54.99 $10.95$65.94

ComponentPrecision Haptic 10mm Vibration Motor - 15mm Type model 1 Precision Microdrives 310-001 3 $7.56 $22.68

ComponentPrecision 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

Component3D 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 MAXIMMAX1555EZK+TCT-ND 2 $2.37 $4.74

Component IC REG LDO 3.3/ADJ 500MA MAXIMMAX1818EUT33+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 $19.98Total Cost: $538.04

P12016: Bill of MaterialsPart Manufacturer Mfr P/N Quantity Unit Price

Total Price - All Units

Shipping/Handling

Subtotal

Microcontroller Texas InstrumentsMSP430F5438A 1 N/A N/A

Digital Compass/Accelerometer

Pololu Robotics and Electronics

LSM303DLH 1 $19.95 $19.95

12 Button Keypad (3x4)Futurlec Electronics

KEYPADSM 1 $2.20 $2.20 $4.00 $6.20

Vibrating Motor (#1)Sparkfun Electronics

ROB-08449 4 $4.95 $19.80 $3.56 $23.36

Vibrating Motor (#2)Pololu Robotics and Electronics

1638 4 $3.49 $13.96 $4.95 $18.91

Battery

RFID Reader

Antenna

Elastic Material

IC BATT CHRGR LI+ 1CELL

MAXIMMAX1555EZK+TCT-ND

2 $2.37 $6.50 $0.00 $4.74

IC REG LDO 3.3/ADJ 500MA

MAXIM MAX1818EUT33+T 2 $3.25 $6.50 $0.00 $6.50

IC USB FS SERIAL UART FTDI FT232RL 2 $4.50 $9.00 $0.00 $9.00

Fasteners - Keypad to Housing

McMaster-Carr 4

Fasteners - Housing to Electronics

McMaster-Carr 4

ABS Plus (3D Print Resin)N/A - RIT Provided

N/A - RIT Provided 1.16 $10 $11.60

M2.5 Spacers - 2mm McMaster-Carr 93657A200 4 $0.87 $3.48

M2.5 Spacers - 10mm McMaster-Carr 93657A212 4 $1.07 $4.28

Rocker SwitchSparkfun Electronics

COM-10727 1 $0.50 $0.50

Battery Jumper Wire/Connector

Sparkfun Electronics

PRT-09914 1 $0.95 $0.95

Questions?