Letter of Transmittal October 14th, 2014 Dr. Andrew
Contents
1. eent 3 Figure 3 Main Microcontroller Input and Output Components EEN 6 Figure 4 Ultrasonic sensors mounted on the VIA neeseerseeesverserssersressvensensseensrnserensensersnsensersnsensersstensenn 8 Figure 5 Audio System Feedback Flow Chart ene 9 iii Sensible Solutions Glossary Accelerometer Measures acceleration Adafruit Trinket Pro Referred to as Trinket The microcontroller used in the marketable and final product Arduino Uno Referred to as Arduino The microcontroller used during prototyping stages Bluetooth A standard for the short range wireless interconnection of cellular phones computers and other electronic devices Braille Written language used by the visually impaired represented by patterns of raised dots Embedded System A computer system with a dedicated function GPS Global Positioning System Gyroscope Determines orientation with respect to the force of gravity Microcontroller A small computer designed to govern embedded systems operations MM Millimeter s MS Millisecond s PCB Printed circuit board Proof of concept a demonstration in principle whose purpose is to verify that some concept or theory has the potential of being used S Second s Ultrasonic Sensor Sensors working off the principle of radar or sonar V Voltage VIA Visually Impaired Assistant Watchdog timer An electronic timer used to detect and recover from computer malfunctions2. as followed Stage 1 Functional Prototype 1 The functionality and placement of the ultrasonic sensors will be outlined 2 The distance measurements of the ultrasonic sensors will be tested and evaluated 3 All components will be integrated though not all may be used for the time being 4 Identification of obstacles will be introduced Stage 2 Prototype Refinement Marketable Product 1 Identification of objects will be solidified and continually tested 2 Audio for feedback control will be implemented through speakers on the device 3 Accelerometer gyroscope functionality will be integrated into the system 4 Anon off switch and control buttons will be integrated onto the device 5 Aclip on wired for hearing audio in noisy environments will be added 6 The design of the device will be evaluated for ergonomic related improvements Stage 3 Final Product 1 LED indicators as a visually impaired warning system will be added 2 A headphone jack will be added for those users who prefer to use earphones headphones 3 Software robustness and reliability will be improved Standards for each of the components of our design as well as for the product itself is something we will be using heavily throughout the process of creation A proof of concept will be delivered by December 2nd 2014 to keep with the required deadlines set forth for the project Our first goal is to keep the user safe and able to feel comfortable moving with
3. standards I R70 II The device shall comply with IEC 60651 Sound level meters 8 5 7 Usability Requirements R71 II The volume of the audio feedback system shall be controlled via device mounted buttons R72 II The clip on speakers shall not cause damage to the user s clothing while clipped on Sensible C Solutions 6 Accelerometer Gyroscope 6 1 Component Overview The accelerometer and gyroscope are key components of the VIA that will help not only detect obstacles but anticipate when the user will reach the obstacle The gyroscope will be used to collect data on the angle that the user is holding the VIA Combining this data with the knowledge of the fixed angles of each of the ultrasonic sensors the microcontroller will be able to accurately measure the user s distance from the obstacle The accelerometer is also used alongside the ultrasonic sensors to approximate the users walking velocity Given the user s velocity and the distance to an obstacle the VIA will be able to predict when the user will encounter said obstacle and provide an appropriate notification For the remainder of section 6 the accelerometer gyroscope shall be referred to as the peripheral 6 2 General Requirements R73 I The peripheral shall make readings independent of the microcontroller R74 II The peripheral shall determine the orientation of the device while running 6 3 Reliability and Durability Requir
4. 3 II Switches and buttons shall be rigid enough to prevent accidental changes yet easily useable by the user R14 II The battery cover shall use a sliding mechanism to minimize the effect of continuous use and wear on the case 2 6 Environmental Requirements R15 i The device shall operate under most indoor conditions R16 II The device shall operate under ideal outdoor conditions R17 II The device shall operate between 20 C to 40 C 21 R18 II The device shall operate between 40 and 90 relative humidity BI R19 II The device shall be water resistant 2 7 Reliability and Durability Requirements R20 I The device shall not output any false positives R21 I The device shall output all confirmed readings R22 The device shall run for 4 consecutive hours on a single charge R23 IV The device shall run for 8 consecutive hours on a single charge R24 II The device shall withstand drops of 1 5 meters R25 II The device shall withstand drops of 2 0 meters 2 8 Standards R26 II The device shall comply with IEC 60529 Degrees of protection provided by enclosures IP Code standards I R27 II The device shall comply with IEC 60085 Electrical insulation standards 3 R28 II The device shall comply with IEC 60086 Primary batteries standards I6l 2 9 Safety Requirements R30 I All components shall be grounded R31 II The device shall be well insulated R32 a
5. I The microcontroller shall be able detect malfunctions and initiate a device reset 3 6 Performance Requirements R54 I The microcontroller shall have a faster clock than all peripherals and components Sensible s Solutions 4 Ultrasonic Sensors 4 1 Component Overview The VIA is designed to have four ultrasonic sensors mounted on it sending proximity readings with a one inch resolution to the microcontroller Three of the sensors will be pointed towards the ground on a single axis yet at different angles These three sensors will be use to detect low obstacles such as a bag or a curb The fourth sensor will gather proximity data directly in front of the user This sensor will mainly be used to detect and anticipate oncoming people or walls Figure 4 shows how the ultrasonic sensors are mounted on the device Sensor Beams Obstacle Figure 4 Ultrasonic sensors mounted on the VIA 4 2 General Requirements R55 I The sensors shall have longer range than the average white cane 1 0 1 5 meters 4 3 Physical Requirements R56 IT The sensors shall not protrude past the device s casing 4 4 Safety Requirements R57 I The sensors shall not cause interference with external electronics R58 I The sensors shall not cause interference with internal components 4 5 Performance Requirements R59 I The sensors shall take 4 readings per second R60 II The sensors will be able to take readings rega
6. Sensible s Solutions 1 Introduction The Visually Impaired Assistant or the VIA is a handheld device created by Sensible Solutions The product uses ultrasonic sensors to detect and identify nearby objects as well as give an approximation of the distance the obstacle is from the user through a small speaker It is a more expensive option than the currently used white cane but with much more information provided to the user to make navigation easier The system must meet the requirements of the user as well as the standards set in place for the different components used These requirements will be outlined in the following documentation 1 1 Scope This functional specifications document will provide an in depth look into the VIA system The document will outline the proof of concept model requirements the features of the product a test plan implementation and finally the safety standards and sustainability of the VIA It will also give a review of the specific stages of our design specifically the difference between our proof of concept model and our intended final working prototype This document will be used throughout the implementation design and development of the VIA system 1 2 Intended Audience This document is intended for a wide range of persons involved in the implementation of the VIA Any member of the Sensible Solutions team specifically the CTO designers and testers can use the functional specifications The Chi
7. Sensible s Solutions Letter of Transmittal October 14th 2014 Dr Andrew Rawicz School of Engineering Science Simon Fraser University Burnaby British Columbia V5A 156 Re ENSC 440 and 305W Functional Specification for the VIA Visually Impaired Assistant Dear Dr Rawicz You will find enclosed the functional specifications for the VIA Visually Impaired Assistant It is our hope to develop a system to help the visually impaired navigate their way through everyday life in a more efficient manner We drive to provide them with a greater amount of information about the environment around them A better solution than the current white cane is in great need and our goal is to improve on this present result This functional specifications purpose is to provide high level design descriptions proof of concept and many of the requirements of our product As well we hope to outline the sustainability and safety of our design Sensible Solutions is composed of three engineering students of a strong and determined mind set Ahmad Ibrahim Robert Sanchez and Jessica Zanewich We appreciate you taking the time to analyze our functional specifications If there are any questions or concerns regarding this document please feel free to contact us by email at jzanewic sfu ca Sincerely Jessica Zanewich Chief Executive Officer Sensible Solutions Functional Specification for the VIA Visually Impaired Assistant Project T
8. The audio feedback volume shall be controlled via volume buttons R33 II Others around the user shall be notified of the user s visual impairment R34 III The device shall notify the user of the battery charge dropping to 20 2 10 Performance Requirements R35 I The device shall be able to distinguish obstacles within 500 ms of detection R36 II The device shall be able to distinguish obstacles within 100 ms of detection R37 I The device shall give audio feedback within 50 ms of distinguishing obstacles R38 III The device shall respond to buttons being pressed within 50 ms R39 I The device shall take 4 readings per second from each ultrasonic sensor R40 I The device shall have an obstacle detection accuracy of 1 inch Sensible C Solutions 2 11 Usability Requirements R41 II The device shall be able to determine and compensate for the user s height within 1 s of the device powering on and being held in the correct position R42 III The device shall be easily serviceable by trained individuals R43 IV The device shall be easily serviceable by untrained individuals using a manual R44 IV The device shall not require more than an annual calibration check service 2 12 Luxury Functions R45 IV Sensors with an accuracy of 1 mm shall be integrated into the device R46 IV GPS functionality shall be integrated into the device for navigation purposes R47 IV Bluetoot
9. UE E 10 6 5 Performance Requirements een 10 TeS OWA EE VEE TEEN A EEE EEE EP ER Eee 11 7 1 General Requirements m sserserssserserssrenssnsseenseovsrensenssrsasensersstenssenseesssersresstensensseenersserenernstennsenstesssenseennsens 11 7 2 Reliability and Durability Requirements ENEE 11 7 3 Safety Requirements m semesrersersssenserssrensnnsrenssovsrensenssrsasensersstensserseessserstenseensenssennerssseeneesstennsenseesstensennssens 11 7 4 Performance Requirements ENEE 11 G User Documenta tomsin aS ea aeaa iaaa TEE Eedse Tet Aaea aaaea asap aiT 12 EENEG 12 8 2 General Requirements seet 12 8 3 Usability Requirements ssersvrasvorsvenssennensvenseensrannnenereneenteanersnseeseennnenseensernerenenenteenenentensennnseetennneeseenne 12 9 System Test Elan eebe EEN 13 9 1 Microcontroller enee 13 EE EE EE EE 13 9 3 Ultrasonic Sensors EEN 13 9 4 Audio Feedback stengt ei es fitness raced debate atin tie ide Gaede 14 9 5 Accelerometer GYLOSCOPE ersersnsensenssteassassrensenssrsasensersatenssenstenssensrenseensrsnsensersstenssenstesssenseenssenseenssensennne 14 9 6 LED External Warning System ssesseesseoseresserserssserserssrenssesseesssossrenseensrsssenssersstenseesstessserseenseenseenseensennne 14 10 Conelusion EE 15 1I Reference Smena a E a A onan enanaoacs 16 List of Figures Figure 1 Block diagram of the VIA s main COoMponents sssssesesssessssssrsrrsrsrrersrrsrsnsnsssssnsnsnsssssssns 2 Figure 2 State machine of Chev
10. currentresults com Weather Canada Cities humidity annual average php Thompson Reuters TechStreet 2013 August 29 Degrees of protection provided by enclosures IP Code CONSOLIDATED EDITION Online Available http www techstreet com products 1864271 product id 186427 1 amp sid goo0g amp g clid CjwKEAjwk_OhBRDO6abu3qSoxlwSJACt7sZ7nX7HUFSVwPLmOq0Lc7sftEX4Sr 4hV75f1u0ulU0P6BoCwEHw wcB International Electrotechnical Commission 1957 January 1 Recommendations for the classification of materials for the insulation of electrical machinery and apparatus in relation to their thermal stability in service Online Available http webstore iec ch webstore webstore nsf standards IEC 2060085 opendoc ument International Electrotechnical Commission 2011 February 17 Primary Batteries Part 1 General Online Available http webstore iec ch webstore webstore nsf artnum 044867 opendocument International Electrotechnical Commission 2012 January 16 Audio Video Similar Electronic Apparatus Safety Requirements Online Available http www drzamps com documents etl web report pdf NoiseMeters Canada Sound Level Meter Standards Online Available http www noisemeters ca help faq standards asp MaxBotix Inc LV MaxSonar EZ1 High Performance Sonar Range Finder Online Available http maxbotix com documents MB1010 Datasheet pdf 16
11. eam Contact Person Submitted to Issued Date Revision Ahmad Ibrahim Jessica Zanewich Robert Sanchez Jessica Zanewich Dr Andrew Rawicz ENSC 440 Steve Whitmore ENSC 305 School of Engineering Science Simon Fraser University October 14th 2014 1 1 Sensible Solutions Executive Summary Expanding the possibilities and depth of field of the visually impaired is highly desired They are unfortunately limited to only a couple of valid options in the current market There are an estimated 285 million people who are regarded as visually impaired worldwide 1 With the VIA we at Sensible Solutions are hoping to change a large portion of these visually impaired people approach the world Our objective is to create a remote like device for a more compact and accurate solution The hope is to use audio feedback through a speaker to indicate obstacles This will give an indication of how far the obstacle is from the person and what kind of obstacle it is It will give the visually impaired a larger awareness radius With our design we are taking some very important measures into consideration Specifically our aim is to give the greatest radius possible but this must also stay very accurate Size and form factor is also a very great consideration With a comfortable ability to hold the device it will be a product worth having Our product will go through three phases of design and we will proceed with development
12. ease in the space around them Sensible s Solutions Table of Contents Executive SUTIN AV Yre i istotkiguges eege seco chngssttssennseebonseanstadcsedeasctenesdureaserannrassediuanestanpcaeetlivaneesenparniaspanisitenste iii GOSS E iv 1 Introduction ee 1 e D EE 1 12 Intended Audiente iniiis nna auai sivaivecevtes eetuteairaiesdnndsitecigivaceaienins 1 1 3 Glassificatio E 1 Z System Requir ments gebuede 2 LESY SCOT V CLV CW eona aA E dea esiea hin 2 2 2 General Requirements smerseressvvsvrenvoensvensrnnsvesennnsveteranerserenterneentenneerrennterstennsenseentrenseenetenseentrenseenerantenssen 3 2 3 Physical Requirements sesseresserserssvenssorsenssersrenseesserrssennserssrennsersersssensresstensensseensenverensenssrensensersasensersstenssen 24 Electrical R quirementsuusinsskndtesesmenmaeenketihbn Ee ee el 2 5 Mechanical Requirements smeesevesvoesveasernsseevennnvnsvensernvreneeenreenvesneeeneenneestenstenseenteenseenerenseenteenseentennersten 2 6 Environmental Requirements 2 7 Reliability and Durability Requirements ENEE 4 EE 4 2 9 Safety Require Ment sessecsseccsscsescessseessessceessteceeesstecseesssecseeeseestessanestessaesanesseessuesseesseesaeeeseeaneeeaeeaneeaness 4 2 10 Performance Beouirements EEN 4 2 11 Usability Requirements nenssserserssvrnsorsvesssersressversrrssennsrssrennsersersssenseessrensenssrensenverensenserensenversnsensersstenssnn 5 2 12 Luxury Funetionsuggussrenueduuumnisensdnstu
13. ef Technical Officer can use this as a standards and safety guide when conducting training for the use of certain components The designers can utilize the requirements set forth to keep with what is expected for the VIA proof of concept and prototype Finally the testers may use this document and the test plan found within as a manual for proper function of different components 1 3 Classification The following convention will be used when listing functional requirements Rn P Functional Specification n denotes the The values of P are as such nth functional requirement I High Priority Required for the proof of concept prototype model P denotes the II Moderate Priority Aimed to be implemented for the priority value working marketable model ranges from I to IV II Low Priority Aimed to be implemented for the consumer product IV Future Consideration Not intended to be implemented as part of the first consumer product may be implemented in future consumer releases Sensible Solutions 2 System Requirements 2 1 System Overview The VIA is a handheld electronic device used to help the visually impaired maneuver through different obstacles in their day to day lives This is done in three key steps gather data from the peripherals processing the data and audio feedback as shown in figure 1 Ultrasonic Sensors Audio Microcontroller Feedback System Accelerometer and Gyroscope Figure 1 Block diagram of
14. ements R75 I The peripheral shall last the lifetime of the device 6 4 Safety Requirements R76 I The peripheral shall have an accuracy of 95 6 5 Performance Requirements R77 I The peripheral shall be able to make 4 readings per second R78 I The peripheral shall output readings within 10 ms after the request is made by the microcontroller 10 Sensible CH Solutions 7 Software 7 1 General Requirements R79 I The software updates shall not require hardware changes 7 2 Reliability and Durability Requirements R80 I The software shall not have memory management issues 7 3 Safety Requirements R81 I The software shall produce warnings when appropriate R82 II The software shall not produce false positives R83 III The software shall detect hardware malfunctions and compensate accordingly R84 III The software shall have a watchdog timer 7 4 Performance Requirements R85 I The software s performance shall not be affected by the runtime duration 11 Sensible lt Solutions 8 User Documentation 8 1 Overview A user manual is included with each device This manual will aid the user in setting up utilizing and troubleshooting their device Two versions of the manual will be provided one in plain text and the other in braille 8 2 General Requirements R86 III The user documentation shall be one all inclusive user guide which includes the warranty d
15. ent is extremely small as it is hardware based A simple on off switch will be linked to the LED which can be easily tested by using the switch However we would want to implement a buzzer to indicate the light is on so a person who is visually impaired will know the light is on 14 Sensible C Solutions 10 Conclusion Sensible Solutions is well on its way to developing the VIA or Visually Impaired Assistant a device that will help the visually impaired navigate safely and confidently in their surrounding environment The functional specifications and requirements established above not only clearly define what the VIA is intended do but also indicate priorities of different features A proof of concept is being developed at this time and is expected to meet all of the high priority requirements mentioned in this document With the gradual completion of each feature of the device the VIA will be able to evolve from a simple prototype to a fully marketable product 15 Sensible Solutions 11 References World Health Organization 2014 August Visual Impairment and Blindness Online Available http www who int mediacentre factsheets fs282 en Statistics Canada 2007 October 12 Weather Conditions in Capital and Major Cities Online Available http www statcan gc ca tables tableaux sum som 101 cst01 phys08b eng htm Current Results Average Annual Humidity at Canadian Cities Online Available http www
16. h functionality shall be integrated into the device for audio feedback purposes Sensible s Solutions 3 Microcontroller 3 1 Component Overview The main purpose of the microcontroller is to facilitate the obstacle detection and to send audio feedback to the user Data is obtained from the ultrasonic sensors accelerometer and gyroscope and is then processed If an obstacle is detected the appropriate audio clip is obtained from the external memory and played on the appropriate audio feedback speaker The components and microcontroller interaction is outlined in figure 3 Aside from these core functions the microcontroller will also be used to rhythmically flash LED lights to indicate the visual impairment of the user 4 Ultrasonic Sensors Figure 3 Main Microcontroller Input and Output Components Speaker System 3 2 General Requirements R48 I The microcontroller shall be able to run Arduino code R49 I The microcontroller shall have enough memory to store the software 3 3 Physical Requirements R50 I The microcontroller shall have enough pins to accommodate all of the peripherals 3 4 Electrical Requirements R51 I The microcontroller shall require no more than 5 V to operate R52 II The microcontroller shall be able to power all of the peripherals without additional electrical components Sensible Solutions 3 5 Reliability and Durability Requirements R53 II
17. isclaimer user manual troubleshooting and contact information R87 III The user documentation shall be in English R88 IV The user documentation shall be in French 8 3 Usability Requirements R89 III The user documentation shall include a braille copy R90 III The user documentation shall include a printed copy 12 Sensible Solutions 9 System Test Plan To ensure a high quality design and execution of the product we will be following a bottom up testing approach This approach requires an intensive unit testing stage where each component will be tested individually We then proceed into integration testing where each component will be integrated into the system individually Each stage of development will have an overall test to ensure the unit is working correctly before moving onto the next stage Using these techniques and timelines for our testing will ensure a solid working device with very few errors to be found in the final product 9 1 Microcontroller Since the Adafruit Trinket Pro is a vital component as it will ensure that we are able to make the ergonomic constraints of the device Since we will be doing a great amount of component testing integration and prototyping with the Arduino Uno we have to ensure that our system is seamlessly ported into the trinket which will entail extensive software testing through simulations and physical testing of the device A lot of the early stage developme
18. ittmludasenndngerigedbine 5 3 MiCrOCOMELOMET sic ces bueren dee EE 6 3 e reene EE 6 3 2 General e TEEN 6 3 3 Physical TE E CN 6 3 4 Electrical Requirements EEN 6 3 5 Reliability and Durability Requirements iseserrssersrrrsvensersersssersressvensensseensenserensensrensensersssensersstenssnn 7 3 6 Performance Requirements 0 essessssesssssssesseesessneesseessessssessecsseestecnsesseecseesueesseesueesaeesneeseesseeseenteeseessees 7 4 Ultrasonic Sensors L vanuimmutuitnthntdde neste ai a a ieia 8 4 1 Component Overview uuaunnasmnusgmnetnnnarnenvsuvitbinnhnnninidesgansi diddirees 8 4 2 General Requirements see NEEN 8 4 3 Physical Requirements EEN 8 4 4 Safety Reouirements EEN 8 4 5 Performance Requirements EEN 8 5 Audio Feedback System nreseressersersssenserssrensserseenssenseenseessrrsseenersstennsenstrsssenstesstensensstensrnsstensennerensensersstenssnnstensenn 9 5 1 Comp onent Overview uauungkengtiemmmeghnknm kbednuuitfedennandhaiiite 9 5 2 General Requirements EEN 9 5 3 Physical Requirements eege ege EE ie 9 5 5 Reliability and Durability Requirements ssessrosseoserssrrenersersssenserssvensenssrensnserensenserensensersnsensersstenssnn 9 BiG Stan Gard EE 9 KAES AE UE 9 6 Accelerometer GyrosCope EEN 10 6 1 Component Overviem innunnmummmmenmnniaismimirinmneeisirivisnele tive eddeduetdestenauautel iiegdeden 6 2 General Requirements 6 3 Reliability and Durability Requirements EENEG 10 Sensible lt Solutions G T AE
19. nd ergonomic case Making the device handheld allows for a smooth transition from the white cane while giving the user freedom to check for obstacles up to 6 meters in front of them This encasement will also come witha sleek wrist strap to help avoid accidental drop damage and misplacements 2 2 General Requirements R1 I The device shall be intuitive to use and has a gentle learning curve R2 I The device shall make correct readings and calculations regardless of the user s height R3 II The final production cost shall be less than CDN 200 per unit R4 IV The final production cost shall be less than CDN 150 per unit 2 3 Physical Requirements R5 I The device shall be ergonomically optimized regarding the device s size shape and weight as to not cause the user discomfort during prolonged use R6 I The device shall not impede the user s movements R7 II The device shall allow for the attachment of wrist straps lanyards to prevent drops R8 II All components and wirings shall be encapsulated within the device s casing 2 4 Electrical Requirements R9 I The device shall be powered via 4 AA batteries R10 III IV The device shall be powered via a rechargeable lithium ion battery pack R11 I The device shall have a rocker switch for its power switch R12 II The device shall have a fuse to prevent electrical surges Sensible C Solutions 2 5 Mechanical Requirements R1
20. nt is done on the Arduino due to the Trinket requiring components to be soldered on A large portion of the Trinket testing happens in the latter half of stage two and all of stage three refer to the executive summary for the description of each stage Since we aim to only integrate the Trinket once everything is working on the Arduino most of the aforementioned testing will be refining the system and getting it ready for the final product 9 2 Software The software build for this device is very important We will be conducting two different types of testing done on the software unit tests and a system test A test simulation is written for each component that extensively tests the software of each specific peripheral of the device Individual software design and analysis has been outlined with specifics in the individual testing descriptions The second type of testing software is the overall checks or system testing Only one software program may be used on the microcontroller which means each of the individual pieces must come together This process will be continuous as it begins with one component and after individual testing of the next part it can be added to the current software program for further testing The system testing after all of the software has been included must be extensive and must involve retesting each component as well as the device as a whole 9 3 Ultrasonic Sensors For testing of the ultrasonic sensor
21. o allow for proper storage and retrieval of sound clips from the memory card The aforementioned retrieved sound clip s are based on the readings of the ultrasonic sensors The audio is the last implementation for the proof of concept model and will very likely require re testing of the other components to produce a well functioning device The headphone jack that is a possible final product component should not affect other components and only require slight hardware retooling and some minor audio tests 9 5 Accelerometer Gyroscope Testing of the accelerometer and gyroscope will have 3 phases The first phase will consist of assuring both the accelerometer and the gyroscope function individually This will initially begin by writing a program that will simply output the tilt angle of the gyroscope The output angle will be compared to the expected readings Another program will then be written to test that accelerometer readings are consistent with what is expected The accelerometer and gyroscope are on a single chip and use the same pins this means the second phase of testing will involve confirming both components can simultaneously output accurate results The final phase involves integrating the fully functional accelerometer and gyroscope with the ultrasonic sensors At this point it is expected that all of the individual components can simultaneously run without any problems 9 6 LED External Warning System The LED testing compon
22. rdless of water resistant features openings might be obstructed to make the device water resistant Sensible s Solutions 5 Audio Feedback System 5 1 Component Overview The audio feedback system as seen in figure 5 will be used only when an obstacle is detected Once this has happened the microcontroller must fetch the appropriate sound clip from memory and then play it on the appropriate speaker Collecting Sensor Data Obstacle Detected Figure 5 Audio System Feedback Flow Chart Play on Bluetooth Speaker Play on Attached Speaker Play on Mounted Speaker Define What Obstacle No 5 2 General Requirements R61 I The device shall use a device mounted speaker s R62 II The device shall use a clip on speaker R63 III The device shall have an audio jack for audio feedback purposes R64 IV The device shall have a Bluetooth system to sync with audio devices 5 3 Physical Requirements R65 II The clip on speakers shall not impede the user s movements 5 5 Reliability and Durability Requirements R66 II The audio feedback shall be clear and understandable R67 III The device mounted speakers shall last the lifetime of the device or easily serviceable R68 II The clip on speakers shall be easily replaceable 5 6 Standards R69 II The device shall comply with IEC 60065 Audio video and similar electronic apparatus Safety requirements
23. s a software program must be created to measure distances with each individual sensor After the validity of each sensor has been tested a second program must be written to test the distance measurements of all four sensors when used together This program must take into account the limitations of the sensors 9 and prevent internal interference since the sensors only function in one frequency 42 KHz 9 13 Sensible Solutions Many different surfaces objects obstacles and distances must be used in the testing of the ultrasonic sensors to ensure the warnings are accurate Sensors may need to be moved to many different placements throughout the testing of the device to provide the best readings possible 9 4 Audio Feedback System The testing of the audio component of our system will consist of both a sound and memory part The audio is strongly associated with the readings of the ultrasonic sensors After the ultrasonic sensor testing has produced precise readings the readings must be used in the testing of the audio For efficiency we will test the audio feedback system by running software simulations while also testing the ultrasonic sensors the integration of the two systems at this point should be trivial Due to the limitations of the Arduino Uno and Adafruit Trinket Pro the audio feedback system requires the use of an SD memory card to store the audio files Hence extension of the software framework must be performed t
24. the VIA s main components The peripherals of which the data is gathered from are the four ultrasonic sensors an accelerometer and a gyroscope Between these six components the microcontroller will have all of the data needed to accurately determine the location of obstacles in the direction that the VIA is being pointed For stage 1 and the first half of stage 2 the processing is done using an Arduino Uno an Adafruit Trinket Pro will be used in the latter half of stage 2 and stage 3 the reason is outlined in section 9 1 The microcontroller will be programmed to then interpret and analyze this data to accurately distinguish between different obstacles the user may encounter These obstacles will include but are not limited to stairs curbs inclines objects and holes The audio feedback system is comprised of an external memory card and the feedback system There are three possible audio feedback systems a mounted speaker and a clip on speaker and a headphone jack The external memory card is needed to store sound clips that will be used to specify any oncoming obstacles Also if the clip on speakers or the headphone jack is in use the mounted speaker will be turned off A diagram of the VIA states is shown in figure 2 Sensible Solutions Collect Data From Sensors Play Appropriate Sound Clip Obstacle Detected Figure 2 State machine of the VIA All of these components will fit into a compact a
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