SDP Presentation1 STEVI: Sensory Technology Enhancement for the Visually Impaired 10/20/2009 Preliminary Design Review Alex StarosielskiSignal ProcessingWeb-Developer.

SDP Presentation 1

STEVI: Sensory Technology Enhancement

for the Visually Impaired

10/20/2009

Preliminary Design Review

Alex Starosielski Signal Processing Web-Developer

Brendan Gavin Sensors / Integration Treasurer

Charbel Kobrianos Sensors / Integration Team Administrator

Yi Lin Feedback / Integration Slide Developments

Team Vouvakis

Electrical and Computer Engineering

SDP Presentation 2Electrical and Computer Engineering

The Problem

The visually impaired can not navigate without assistance.

•Cane

•People

•The Guide Dog

SDP Presentation 3Electrical and Computer Engineering

Long Cane

• Common Solution

•Simple, cheap, robust and reliable

• Limited range

• Problems with obstacles above waist.

SDP Presentation 4Electrical and Computer Engineering

Electronic SolutionsElectronic Travel Aids (ETAs) • Detect obstacles with sensors

•Typically ultrasonic

• Indicate obstructions to user

•Feedback often auditory or tactile

SDP Presentation 5Electrical and Computer Engineering

Limitations of Existing Electronic Aids

•Expensive! $400 to $1000

•Trouble with stairs and slopes

•Insufficient directivity

•Problems with reflections indoors

•Problems with absorbing objects

Requirement Specifications

SDP Presentation 6Electrical and Computer Engineering

Society Needs Engineering Constraints Project Specs

Form Factor Handheld Size 5in x 5in x 2in (handheld)

Detection Range

0 – infinity Power and price 0.5-4m

Detection Angle

0 – 180° User interface and signal processing 20°

Obstacle sizes

All sizes Limitations of sensors > 3in x 3in

Cost Free Part, manufacturing and labor costs < $400

Battery Life Infinite Size, power consumption > 7 hours

Weight Negligible Hardware mass < 3 lbs

Big Picture

7Electrical and Computer Engineering SDP Presentation

SDP Presentation 8Electrical and Computer Engineering

Proposed Solution - STEVI

Sensor Fusion!

Auditory & Tactile Feedback

Ultrasound Laser Infrared

Small Objects X

Slanted Surfaces X X

Directionality X

Reflections Signal Processing

Absorbent Objects Signal Processing

Block Diagram - Basic

SDP Presentation 9Electrical and Computer Engineering

Block Diagram - Intermediate

SDP Presentation 10Electrical and Computer Engineering

SDP Presentation 11Electrical and Computer Engineering

Block Diagram – Full Function

SDP Presentation 12Electrical and Computer Engineering

Ultrasonic Sensors2 x Maxbotix UT

• Average time of flight to calculate distance

• Angle calculated from difference in signal return times

c = speed of sound in air = 343 m/s

www.sparkfun.com

SDP Presentation 13Electrical and Computer Engineering

Laser

• Detect distances with triangulation

• Used for handling stairs, curbs, angled walls and smaller objects

•(1/3-inch Sony Supper HAD Color CCD Wired Mini Pinhole Camera

Camera view:

Setup:Sony Supper HAD

www.lightinthebox.com

Infra Red

• Detect closer objects

• Prevents user from hitting objects while sweeping left and right

www.sparkfun.com

• Has a viewing angle of 40 deg.

14SDP PresentationElectrical and Computer Engineering

SDP Presentation 15Electrical and Computer Engineering

Microcontroller

• 3 x 28 pin ATMega88PA• Features: • 8kB Program Space • 20 MIPs at 20 MHz

• 23 I/O Lines, 6-channel 10 bit ADC• In-circuit programming - JTAG

www.digikey.com

SDP Presentation 16Electrical and Computer Engineering

User Feedback

3 x ROB-08449 Vibrating Motor

• Closer obstacle - stronger vibrations• Vibrating pad location - obstacle direction• Alternative Feedback - Audio Jack

www.sparkfun.com

SDP Presentation 17Electrical and Computer Engineering

Prices

Component Cost

Microcontrollers (3)www.digikey.com

$8

Vibrating Motors (3)www.sparkfun.com

$15

IR Emitter/Detector (2)www.sparkfun.com

$4

Ultrasonic Transducers (2)www.sparkfun.com

$10

Laser/Camera Assemblywww.allelectronics.com

$140

PCB Fabrication $100

Total Cost $277

Initial Balance $500

Net Savings $223

SDP Presentation 18Electrical and Computer Engineering

Proposed MDR Deliverables

Demonstration of Ultrasonic Detection• Block Diagram 2 • Ultrasonic Transducers• Transducer Microcontroller• Vibrating Motor Array

Principles of Laser Detection• Laser and Camera• Computer Processing

Gantt Chart of STEVI

Thank You

SDP Presentation 20Electrical and Computer Engineering