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
