Navigational Aid for a Blind Deaf Individual

Konrad Ahlin Ben Davidson

Bob Evans Jackson Lamp

David Sachenik Rob Steigerwald

David Yip

Design Goals Able to communicate effectively with

deaf blind individuals Weight cannot exceed 4 ounces Must fit within a 4 x 2 x 1 inch volume Must be reasonably inconspicuous Will track position using RFID tags Power must last for ten twenty minute

uses Cost to produce must not exceed $700

*antenna not counted in weight and size requirements

Concerns Volume Constraints Weight Constraints Heat Dissipation Attaching device to belt Program Accuracy PCB Design and Functionality

Size of Components

ComponentsLength (in)

Width (in)

Height (in) Inch cube

Microcontroller 0.551 0.551 0.063 0.019

Reader 2.756 2.087 0.354 2.038

Keypad 2.008 2.520 0.276 1.394

Battery 2.09 1.3 .225 .6113

Magnetometer 0.9 0.5 0.1 0.045

Size of Components Cont’

ComponentsDiam Height Inch cube

Side Motor 0.394 0.907 0.110

Side Motor 0.394 0.907 0.110

Middle Motor 0.472 0.134 0.023TOTAL VOLUME: 3.802

Outer Dimensions

ComponentLength (in)

Width (in)

Height (in) Inch cube

Main Case 2.91 2.25 1.38 9.04

Component Diam (in)Height (in) Inch cube

Side Case 0.5 1.2 0.197

Components Inch cube

Total Volume: 9.44

Weight of ComponentsComponents Weight (oz)

Microcontroller TBD

Reader 0.441

Keypad TBD

Magnetometer 0.028

Battery .77

Side Motor 0.229

Side Motor 0.229

Middle Motor 0.060

Case Total 1.18TOTAL: 3.069

Power ConsumptionRFID Antenna 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

Battery is 3.7V, 1100mA*hr, 4.01W*hr

Heat Analysis – Hand Calculations

Conduction caused by air: Section of chip 0.1” x 0.1” A=6.45*10-6 m2

Q= -KA (dT/dx) QTotal=1.6W QPart =1.6W/210 = 0.00762W K= (about) 0.0257 Wm-1K-1

dT/dx = Q/(-KA) dT/dx = 0.00762/(0.0257*6.45*10-6) = 45969 degC/m

=649 degF/in =64.9 degF/0.1in

Chip

Air

Heat – Experimental Results

0 5 10 15 20 2580

90

100

110

120

130

140

Chip Temp (deg F) Case Air Temp (deg F)Time (mins)

Tem

p a

bove C

hip

(deg F

)

Null hypothesis: Average temperature < 120 deg F

95% ConfidenceAlpha = 0.05Mean=113.9P-Value=1.00

Fail to reject null hypothesis

Heat – Analytical AnalysisCase thermal conductivity = 0.2 Wm-1K-1

Outside case temp set to 20 deg C

Top of chip set to 54 deg Celsius (130 deg F)

Bottom of chip insulated

1) Region Map

2) Nearest Tag ID(s)

3) Destination

9) Charging Power

20) Off Path

21) Hardware Health

22) Movement Instructions

5) Receive Map Info

12) Record location history

14) Regulate Power

Enclosure: Support & Manage Internal Components

7) Receive User Input

13) Calculate

path

8) Determine Orientation (Compass)

6) ID current

location

11) Compare current to map

16) Calculate next

movement instruction

18)

Del

iver

Non

-Pro

mpt

ed

Info

rmat

ion

to U

ser

Via

Hap

tic

Feed

back

15) Monitor Hardware Health

(MCU: Define Interfaces with Power, User Input,

Map Input, RFID Reader, Magnetometer, Output

Drive Circuitry)

10) On-Board Power

Navigation Loop

Battery Life

Connectivity of Modular

Devices

19)

Del

iver

Pro

mpt

ed

Info

rmat

ion

to U

ser

Via

Hap

tic F

eedb

ack

23) On Correct Path

24) Button Pushed

25) Estimated Remaining Distance

17) Estimate Remaining Distance4) User Input

Destination Arrival

Turn

Functional Decomposition

Final Design Design elements kept from previous years

RFID tag and reader Keypad input

Changes from previous years Vibratory haptic feedback

Two motors for directional feedback One motor in base unit for input confirmation

Modular belt design Two motors Base unit with keypad Separate antenna

Schematic of Build (outer case)

Schematic of Build (Battery)

Schematic of Build (RFID)

Schematic of Build (PCB)

Schematic of Build (Keypad)

Schematic of Build (Cover)

Schematic of Build (Motor Case)

Procedure of Build Week 1

Motor Testing (without case) Antenna Testing

PCB Prototyping Board Week 2

Finalize design and build motor case Motor Tests (with case) Testing of Magnetometer Order Wiring and Belt

Week 3 Order Base Case Test Keypad

Procedure of Build Cont’ Week 4

Test PCB Start design for part placement in case Order spacers and insulation for case Have developed program to start testing

Week 5 Re-machine Case and continue fitting parts Test connections and interactions between MCU and

other devices Order PCB

Week 6 Test Durability of general design Finish Full Build

Week 7 Application testing of device

Week 8 – 10 Presentation Set up

Haptic Feedback Motors

Navigation Feedback Precision Haptic 10mm

Vibration Motor - 15mm Type

Input Confirmation

Pico Vibe 12mm Vibration Motor - 3.4mm Type

Motor Tests Volt Step Testing

Orientation Testing

Case Material Testing

Duty Cycle Testing

Applied Force on Case

Motor Testing Results310-002

Voltage Current (mA) Vibrating IntensityBest Orientation

0.1 13.6no N/A0.2 27.3no N/A0.3 41no N/A0.4 47.5no N/A0.5 51.2yes light N/A0.6 61.2yes light N/A0.7 76.1yes moderate N/A0.8 89.4yes moderate N/A0.9 101.2yes moderate N/A

1 114.4yes moderate N/A1.1 361.5yes high N/A1.2 400yes high N/A1.3x x x

User InputsCommand/ Request Step 1 Step 2 Step 3

Guide to room #?????? *

Enter 6 Didgit room number *

Guide to Closest Bathroom * 1 *

Guide To Closest Water fountain * 9 *

Test Left Motor * 4 *

Test Right Motor * 6 *

Test Center Motor * 5 *

ETA /On-Track * 0 *

Cancel Request # #

Enter Sleep Mode * # *

User Confirm * *

Outputs to User (Automated)

Output to User

Duration of Vibration (s)

Time Between Vibrations (s)

Frequency (Hz)

Duty Cycle (%) Which Motor Repeat

Turning Warning Pulse 2N/A N/A N/A Turn Side Motor

Test on entered testing instruction. Pulses and then turns off

Turning Vibration 3 1 0.25 75Turn Side Motor

Continues to cycle until turn is accomplished or off track instruction is activated

Warning Battery Low 4 1 0.2 80

Both Side Motors

Goes throught the cycle till use confirms they understand

Warning for Off_Track 4 1 0.2 80Center Motor

Goes throught the cycle till use confirms they understand

Destination Arrival Confirmation 1 1 0.5 50

Both side Motors

Goes through the cycle till use confirms they are in the room

Outputs to User (User Generated)

Output to UserDuration of Vibration (s)

Time Between Vibrations (s)

Frequency (Hz)

Duty Cycle (%) Which Motor Repeat

ETA 0.5 0.5 1 50Center

Active on user instruction. Pulses for the number of tags in list still to come

Testing Vibrations 1N/A N/A N/A Tested Motor

Test on entered testing instruction. Pulses and then turns off

Number Button Push Confirmation 0.5 0.5 1 50Center

Vibrates for number of pulses equal to numeric number of button

Testing of Total Design Heat

Internal Temperature must be less than 120 degrees Fahrenheit

Drop Must be fully functional after a free fall

drop from 3 feet Guidance

Must accurately guide an individual from any location on the second floor of Building 9, to any designated location

Testing of Total Design (cont’) Battery Replacement

Must take less than 1 minute Charge Time

Charges in 8 hours or less Power Consumption

Can Run for at least 200 minutes on 1 charge

Removal and attachment of device Less than 1 minute

P12015: Bill of Materials

Type Part Manufacturer 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 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

Project Timeline

Risk AssessmentMCU Lead Time Taking too long

Motors Vibrating too had for leads

Motors Burning Out

Fails Drop Test

Keypad Lead Time

Questions?