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
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
Risk AssessmentMCU Lead Time Taking too long
Motors Vibrating too had for leads
Motors Burning Out
Fails Drop Test
Keypad Lead Time