WEARABLE NAVIGATION DEVICE FOR THE BLIND MSD II - TEAM P12016 MAY 18, 2012 Based upon work supported by the National Science Foundation under Award No. BES 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.

PRESENTATION AGENDA 1. Team Roles 2. Introduction & Requirements 3. Physical Components 4. Software & System Architecture 5. Subsystem Testing 6. System-Level Assembly 7. System-Level Testing & Spec Comparison 8. Lessons Learned 9. Future Work 10. Q & A

TEAM ROLES Oliver Wing | CE Path-finding algorithm Path-following algorithm Software & functionality testing Curtis Beard | EE PCB design Testing & support Stu Burgess | ME Plastic enclosure design Mechanical assembly & tolerances Thermal modeling Magy Yasin | ISE Scheduling Test creation & documentation Attachment manufacture Dave Taubman | EE PCB design PCB testing & support Algorithm creation Jeff Chiappone | ME Plastic enclosure design Stress testing Poster design Aalyia Shaukat | EE PCB design Testing & support ? Jackson Lamp | CE Path-finding algorithm Path-following algorithm ?

INTRODUCTION & REQUIREMENTS Description: The blind face numerous challenges when navigating inside buildings Braille not always helpful - only 10% read it Sought to design wearable electronic device for this purpose Customer Requirements: Lightweight, fairly conspicuous, easy to use/learn Guides towards a destination, warns if detract from path Provides non-visual/non-auditory feedback (not Braille) General Requirements: Resilient, withstands 3-foot drop Allows user to change battery in <1 minute Goals for this project: Dramatically reduce size, weight of previous projects Less conspicuous Focus on portability, have enclosure contain all components

COMPONENTS & SUBSYSTEMS

PHYSICAL COMPONENTS Printed circuit board Links together all other electronics Contains micro-controller unit Vibrational motors Send out long or pulsed vibrational feedback User senses these and interprets for directions RFID tag reader Acts as the “eyes” of the device Senses RFID tags in building Numeric keypad Takes room number input from user Magnetometer Keeps device working properly in any orientation Antenna Senses RFID tags for reader Housing enclosure Houses all electronics Allows easy access to battery Elastic sleeve Holds electronics to body Keeps device secure and wearable

SOFTWARE & SYSTEM ARCHITECTURE

SUBSYSTEM TESTING Image of thermal test results? 92% 98% 100%98% 90% 100% Drop Tests: Qualification: must survive fall of 3 feet onto concrete Result: device passed, no fracture or cracking Ergonomic Testing : Qualification: highest percentage of vibrations perceived over all other locations Result: three distinct locations chosen with specific distance determined by additional qualitative testing. Thermal Testing: Qualification: air inside device can not exceed 120 degrees F Result: housing successfully dissipates enough heat during use to meet the qualification Input Loop Testing: Qualification: prioritize reset, verify room # entry, respond to pause/resume Result: keypad input always accepts reset, even while receiving and filtering room # entry and navigation commands

PROTOTYPE & SYSTEM-LEVEL RESULTS

SYSTEM-LEVEL ASSEMBLY Vib. motor locations Battery door (faces this way) Wiring Housing enclosure PCB & connectors Keypad RFID Ergonomic curvature Housing enclosure Component stack-up

SYSTEM-LEVEL TESTING & SPEC COMPARISON Image of battery door with batt. slid out partially Path-finding: Qualification: Given starting and ending locations, the program can calculate a shortest path Result: Device can take any two points on the map and store the nodes on a shortest path from one to the other for path following. Path-following: Qualification: Correctly issues turn signals and other status information to the user based on calculated path and user's current location Result: Device is able to monitor location by detecting RFID tags and offer turn feedback based on heading comparison with the magnetometer. Reliability is still untested due to interface glitches. Battery replacement | Put-on | Take-off : Qualification: Each process should take less than one minute to complete. Result: The user is able to attach and remove the device in less than a minute. Battery door gives quick access to battery allowing it to removed quickly

RESULTS & CONCLUSIONS

LESSONS LEARNED Mechanical: The time for ideation is slim-- brainstorm quickly, then arrive at a solution Rapid prototyping is a successful choice for quick turn-around and cost effectiveness Rapid prototyping will always be much less precise than expected- plan accordingly for fit and tolerances More than one iteration may be required for a good fit between mating plastic parts Hardware: Become familiar with all interfaces to the MCU, and develop interface code with a development kit in late MSD I / early MSD II Collaborate directly with other teams or previous team/project members if possible Always plan for 1-2 weeks of changes/debugging to PCB even if design seems finalized Software: Write testbenches for software that can run without one or more sensors, in case the interface code is slower to develop than the algorithms Make the code easily configurable for different hardware destinations (i.e., dev kit vs. end PCB design)

FUTURE WORK Include obstacle detection Design attachment so that device could be worn on either hand Expand to include multiple floors and buildings Replace RFID Reader Include auditory output as an additional option for feedback