Tactile Navigation System
for the Blind & Visually
Impaired (VI)
Presented by:
Tim Giguere & Tim DeBellis
Shannon Carswell & Tim Garvin

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
Problem Statement
Intra-Building Navigation: Functional
Decomposition
Intra-building Navigation:
Concept Generation
Navigate
Building
Input
Destination
Keypad
Voice
Braille
Automaticread
schedule
Read
Location of
User
RFID
GPS
IR
Ultrasound
Generate
Directions
Compass
Map
Piece by
Piece
Direct.
Compass
and Map
Interface
Directions
Sound
Digital
Display
Tactile
Display
Braille
Display
Track
Location
RFID
GPS
IR
Ultrasound
Verify
Location
Tag Id’s
GPS
Location
Ultrasound
Readings
IR Signature
Intra-Building Navigation: Concept Selection
Step #1 Screening
RFID
IR
Web
Dog
(REF)
2 RFID
tags
RFID and
IR
Aug.
GPS
RFID and
Compass
Availability of parts
+
+
+
D
+
+
-
+
Distance
0
0
0
0
0
+
0
Cost of parts
+
+
-
+
+
0
+
Size
+
+
+
+
+
+
+
Accuracy
+
+
0
+
+
+
+
Ease of Integration
+
+
+
+
+
+
+
Cost of upkeep
+
+
+
+
+
+
+
Sum + 's
6.00
6.0
0
4.00
6.00
6.00
5.00
6.00
Sum 0's
1.00
1.0
0
2.00
1.00
1.00
1.00
1.00
Sum -'s
0
0
1
0
0
1
0
Selection Criteria
A
T
U
M
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
Read Range for Alien 'G' Inlay with PS
0˚
345˚
360˚ 60
330˚
Test Procedure:
◦ Initial Read Range
 USB
 Power Supply
◦ Surface
◦ Height Placement
◦ Engineering Specifications
 Accurate Directions
 Repeatability
◦ Directions
◦ Location Identification
 Latency
 Mean Learning Time
30˚
45˚
40
315˚

15˚
50
60˚
30
300˚
75˚
20
10
285˚
90˚
0
270˚
105˚
255˚
120˚
240˚
135˚
225˚
A50
150˚
210˚
195˚
180˚
A49
165˚
A48
Read Range for Alien "G" with USB
0˚
360˚
50
15˚
345˚
30˚
40
330˚
45˚
30
315˚
60˚
20
300˚
75˚
10
285˚
90˚
0
270˚
105˚
255˚
120˚
240˚
135˚
225˚
150˚
210˚
195˚
180˚
165˚
A50
A49
A48
Intra-Building Navigation: Interface
Intra-Building Navigation: Navigation

‘Hybrid’ Algorithm
◦ Graph Traversal
◦ Area Navigation
A
B
C
Intra-Building Navigation: Navigation

‘Hybrid’ Algorithm
◦ Graph Traversal
◦ Area Navigation
A
B
C


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
means

Device operation dependent on customer
needs.
System Integration
Customer Needs



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

Stress Analysis

Fatigue Analysis

Vibration Analysis of Motor
◦ FEA models for compressive load
scenarios
◦ Servo-arms tested under bending
with servo max stall torque.
◦ Modified Goodman Criteria applied.
 Plastic component stresses
applied to research data for
fatigue conditions
◦ 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
Mechanical System Design
Analysis





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





Individually test
components for
functionality
Prototype system
using PIC
development kit
Create ‘front end’
user inputs
Move design to
PCB
Verify power levels
Electrical System Design Strategy
Tactile Team:
Navigation Team:
Christian Seemayer (EE)
Shannon Carswell (EE)
Rob Proietti (ME)
Daniel Paris (EE)
William Kelly (ME)
Tim Garvin (CE)
Tim DeBellis (EE)
Daniel Stanley (CE)
Tim Giguere (ME)
Sponsors:
Advisor:
Dr. Elizabeth DeBartolo