Tactile Navigation System Tactile Navigation System for the Blind & Visually for the Blind & Visually

Impaired (VI)Impaired (VI)Presented by:

Tim Giguere & Tim DeBellisShannon Carswell & Tim Garvin

Problem StatementProblem Statement

Objective: Develop a device to aid the VI and blind in navigation throughout a building using a tactile interface.

Issues Faced:◦ Campus and Classroom navigation◦ Predominate use of memory for navigation◦ Current market technology unreliable and expensive

This is a combination of two Senior Design Projects:◦ Intra-Building Navigation ◦ Tactile Interface

Intra-Building Navigation: Functional Decomposition

Intra-building Navigation:Concept Generation

Navigate Building Interface

Directions

Input Destination

Read Location of

User

Generate Directions

Track Location

Tag Id’s GPS Location

Verify Location

Ultrasound Readings

IR Signature

RFID GPS IR Ultrasound

Sound Digital Display

Tactile Display

Braille Display

Compass Map Piece by Piece Direct.

Compass and Map

RFID GPS IR Ultrasound

Keypad Voice Braille Automatic-read

schedule

Intra-Building Navigation: Concept SelectionStep #1 Screening

 

 RFID IR

Web

Dog (REF)

2 RFID tags

RFID and IR

Aug. GPS

RFID and CompassSelection Criteria

Availability of parts + + + D + + - +

Distance 0 0 0   0 0 + 0

Cost of parts + + - A + + 0 +

Size + + +   + + + +

Accuracy + + 0 T + + + +

Ease of Integration + + +   + + + +

Cost of upkeep + + + U + + + +

Sum + 's 6.006.00 4.00   6.00 6.00 5.00 6.00

Sum 0's 1.001.00 2.00 M 1.00 1.00 1.00 1.00

Sum -'s 0 0 1   0 0 1 0

Net Score 6 6 3   6 6 4 6

Rank 1 1 3   1 1 2 1

Continue? YES YES NO DATUM YES YES NO YES

Intra-Building Navigation: Concept Selection

Intra-Building Navigation: Selected Concept

RFID Technology◦ Place passive tags throughout the building to identify

locations◦ Use the reader to track location of user◦ Develop navigation algorithm to produce directions

between user and desired location

Compass◦ Provide initial bearing to produce accurate directions

Intra-Building Navigation: RFID Testing and Results

Test Procedure:◦ Initial Read Range

USB Power Supply

◦ Surface◦ Height Placement◦ Engineering Specifications

Accurate Directions Repeatability

◦ Directions◦ Location Identification

Latency Mean Learning Time

Read Range for Alien 'G' Inlay with PS

0

10

20

30

40

50

600˚

15˚30˚

45˚

60˚

75˚

90˚

105˚

120˚

135˚

150˚165˚

180˚195˚210˚

225˚

240˚

255˚

270˚

285˚

300˚

315˚

330˚

345˚360˚

A50

A49

A48

Read Range for Alien "G" with USB

0

10

20

30

40

500˚

15˚30˚

45˚

60˚

75˚

90˚

105˚

120˚

135˚

150˚

165˚180˚195˚

210˚

225˚

240˚

255˚

270˚

285˚

300˚

315˚

330˚

345˚

360˚

A50

A49

A48

Intra-Building Navigation: Interface

Intra-Building Navigation: Navigation

‘Hybrid’ Algorithm◦Graph Traversal◦Area Navigation

B

A

C

Intra-Building Navigation: Navigation

‘Hybrid’ Algorithm◦Graph Traversal◦Area Navigation

B

A

C

System IntegrationSystem Integration

Develop a tactile interface that blind and VI individuals can use as a personal navigator

Device operation:◦Destination Input◦Entry to Internal Map comparison◦Directional information relay to user via tactile

meansDevice operation dependent on customer

needs.

Customer Needs Customer Needs

Mechanical System DesignMechanical System Design

Housing Structure Top and Side walls

constructed from HDPE and Garolite plastic.

Bottom is rapid-prototyped at RIT Brinkman Lab.

Directionality Servo-driven tactile pegs Tactile pegs made of HDPE

Proximity Vibration Motor Controlled by pulse width

module to output 2 second vibrations

Mechanical System Design Mechanical System Design AnalysisAnalysis

Stress Analysis◦ FEA models for compressive load

scenarios◦ Servo-arms tested under bending

with servo max stall torque. Fatigue Analysis

◦ Modified Goodman Criteria applied. Plastic component stresses

applied to research data for fatigue conditions

Vibration Analysis of Motor◦ Issue of human exposure levels.◦ 5 m/s^2 max for exposure time

allowed.◦ From testing, motor reaches

between 25 and 55 minutes of constant exposure

Electrical System DesignElectrical System Design

Built around an 8-bit PIC C-based microcontroller.

Motors controlled by PIC and driven by BJT network.

Keypad continuously polled in software, user entry stored in variable length string

String will eventually compared to internal map to provide directional info

6V rechargeable NiMH battery

Electrical System Design StrategyElectrical System Design Strategy

Individually test components for functionality

Prototype system using PIC development kit

Create ‘front end’ user inputs

Move design to PCB

Verify power levels

Tactile Team: Navigation Team:

Sponsors:

Advisor: Dr. Elizabeth DeBartolo

Shannon Carswell (EE)

Daniel Paris (EE)

Tim Garvin (CE)

Daniel Stanley (CE)

Christian Seemayer (EE)

Rob Proietti (ME)

William Kelly (ME)

Tim DeBellis (EE)

Tim Giguere (ME)