NAVIGATION AID FOR THE BLIND

P12015

This material is based upon work supported by the National Science Foundation under Award No. BES-0527358. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.

FACULTY GUIDE: DR. BETH DEBARTOLO

Our Engineering Team

From Left:Bob Evans Electrical EngineerDavid Sachenik Electrical EngineerJackson Lamp Computer EngineerDavid Yip Electrical EngineerBen Davidson Mechanical EngineerRob Steigerwald Industrial Systems EngineerKonrad Ahlin Mechanical Engineer

Project Description

• Creation of a device that allows a vision/hearing-impaired individual to easily navigate to a location in an unfamiliar building.

• Our device understands locations by recognizing various passive radio-frequency identification (RFID) tags that are placed by doorways, restrooms, water fountains, and other areas of interest.

• The navigation algorithm calculates and determines the quickest routes to user inputted destinations.

• Complete prototype is user friendly, comfortable, and hands free.

Project requirements

•Battery Charge time less than 8 hours

•Interchangeable Battery

•Non-visual Commands

•Generates less than 50 dB Noise

•Attachment Time less than one minute

•Impact Resistant

•Lightweight

•Reliable

Electrical Design

Central Processing Unit: • MSP430F5438A Microcontroller

Determines Heading of User: • LSM303DLH Magnetometer

Determines Location of User: • SkyeTek SkyeModule M9 RFID Reader

Power Source: • Polymer Lithium Ion Battery – 1000mAh

Electrical Design

RFID Reader Antenna: •HyperLink Wireless 8 dBi Flat Patch Antenna

User Input Device:•3x4 Numerical Matrix Keypad

Defines Locations Within Building:

• Alien-Higgs Passive RFID Tags 840-960MHz

Provides Feedback to User:• Precision Microdrives 10mm Vibration Motors 400mA

Electrical Design PCB Layout

Software Design

Two Step Navigation Process:

1.) Path Finding:• Implementation based on Dijkstra’s

Algorithm• Path is stored for use by the path

following algorithm• Re-run whenever the user wanders off

course

2.) Path Following: • Currently a work in progress• Interprets data generated by the path

finding algorithm to guide user to guide user to destination

Software Design

Management of Peripheral Devices:

• Custom Interface for Keypad• Uses a sequence of pulses to scan each column of keys

• SPI Interface for RFID Reader• Uses a packet based, request-response protocol• Current implementation can return a list of detected tag IDs• Challenging to implement, caused delays in

• I2C Interface for Magnetometer• Uses a register based protocol• Raw data needs to be converted into a heading value using

trigonometry• PWM Output for Vibration Motors

• Used to control intensity of vibrations programmatically• State base controller used to control output sequences

Mechanical Design

Main Case:• Slide allows for easy battery

access• Top cover holds keypad in

place• Main body holds PCB, RFID

reader, and battery in place

Motor Cases:• Transmits vibrations• Allows offset mass to rotate

Belt Enclosure:• Ergonomically designed• Properly secures components

Results/Demonstrations• Motor Feedback Interaction• User Keypad Inputs• RFID Tag Recognition• Magnetometer Heading• Assembly of Device