MSD P13038 Hearing Aid Design

System Design ReviewJanuary 11, 2012

Team Members 1.11.13

Alissa Anderson Team Manager

Conor Murphy System Integration Engineer

Ronald Dries Lead Electrical

Kelly Murosky Lead Mechanical

Nanxi Yu EDGE Master

Paula Garcia Secretary

Eric Lew Budget Master

Marbella Vidals Customer Relations

Sarah Brownell Guide

Agenda 1.11.13Project Overview (5 minutes) - Background - Motivation- Major customer needs, specs, and functions

Mechanical Design (10 minutes) - Enclosure renderings - Mechanical architecture - Hot Topic: User-centered design

Electrical Design (20 minutes) - Electrical architecture- Hot Topic: micro-processor selection and power distribution

Software Design (15 minutes) - Software architecture - Hot Topic: System simulation and filtering methods

Project Plan (10 minutes) - Critical Path- Major risk summary - Budget review

Background & Motivation 1.11.13Expected Project Benefits:

(1) De-stigmatize hearing aids as medical devices by creating an audio accessory that is socially accepted and used by both hearing and hard of hearing individuals.

(2) Provide hard-of-hearing market with an alternative hearing aid device that offers similar features contained within a new physical form

(3) Project is to serve as an initial proof of concept for future MSD projects to focus on improvements in device adjustability and functionality

Target Audience: hearing and hard-of-hearing, young hearing aid users Oticon, Agile

Functional Decomposition 1.11.13

amplify sound

process sound

capture sound

modify sound

filter sound

adjust by frequency

supply power

store energy

transform energy

output energy

accept energy

interface with user

accept ear

fits comfortably

protects user

resists water and shock

controls volume

manages heat

program device

accepts data

stores data

user input

recognizes input

stores input

adjusts system to input

raise sound level

track power level

modify function to data

output sound

Design Constraints (ME/ID) 1.11.13

Customer Need

Rank Description

CN2 9 The device fits most adult ears ages 15-25years

CN3 9The device does not draw attention to the user as a hard of hearing individual

CN4 9The device supports an active lifestyle (stays on the ear during everyday activities and light activities)

CN7 9 The device is rechargeable by computer USB port

Spec Source Specification DirectionUnits of

measure Marginal Ideal

S9CN2, CN4,

CN11Range of adult ear size

accommodatedmax percentile

25th to 75th

10th to 90th

S10CN4, CN6,

CN10, CN11Weight of earpiece min g <15 <12

S14 CN3

Percent of serveyed people who identify a picture of the device as something other than a hearing

aid.

max percent >60 >80

S15 CN3

Percent of surveyed hard of hearing people who prefer the

form of the new device to standard behind the ear hearing

aids

max percent >50 >75

S17 CN11Percent of surveyed people who feel the device is comfortable to

wearmax percent >60 >80

Benchmarking 1.11.13

Enclosure Proposal 1.11.13

Key Features:

Processes and amplifies sound based on custom user hearing profiles

Rechargeable power source

Reprogrammable software for changes in user application

Interfaces with USB 2.0

User control of volume, power, and profile setting

Interfaces with standard ear tube and ear mold styles (custom fit, dome, etc.)

Optimized number and location of microphones for sound capture

Enclosure Proposal 1.11.13

detachable “Transfer Module”

Design Constraints (EE) 1.11.13

Customer Need Rank Description

CN1 9 The device amplifies sound

CN7 9 The device is rechargeable by computer USB port

Spec # Source SpecificationDirecti

onUnits of

measure Marginal Ideal

S1 CN1 Lowest level of sound detected min dB <60 <30

S2 CN1 Frequencies amplified max Hz N/A 85-8000

S3 CN1, CN6 Maximum amplification target dB 85-95 90

S5 CN7 Time to charge earpiece min minutes <60 <30

S7 CN7Connects to standard USB 2.0

computer porttarget yes/no yes/no yes

S12 CN8Earpiece battery life at maximum

amplificationmax hours >16 >48

Proposed Budget 1.11.13

Item Qty Cost ea. Total

Evaluation Boards 7 $200 $1400

Microphones 2 $100 $200

Microprocessor 3 $150 $450

Amplifier components 1 $70 $70

Speaker 2 $50 $100

USB Interface 1 $20 $20

Rechargeable Battery 10 $15 $150

PCB 4 $50 $200

Acoustic Test Stand 1 $500 $500

3D Printing Costs 7 $75 $525

Miscellaneous X X $1000

TOTAL $4615

Timeline: Critical Dates 1.11.13

Date Event DRI

Jan 7Enclosure sketches due (select 2 potential product options)Finalize scope, deliverables, needs

ID

Jan 11 System Design Review ALL

Jan 17 Order Eval Boards  EE

February 7Printed Circuit Board (PCS) 1.0 Printed Enclosure Alpha Printed

EE

February 15 Detailed Design Review ALL

March 29Final PCB printed and on campus (for integration) Final enclosure printed (for integration)

ME

April 1 Start integration and debug ALL

April 26 WORKING PROTOTYPE DUE ALL

May 4 Imagine RIT ALL

May 10 Final MSD Review (Week 10) ALL

Risk Assessment 1.11.13ID Risk Item Effect Cause

Likelihood

SeverityImportance

Action to Minimize Risk Owner

1Project Scope too large

due to large scope, deliverable list is too large and project is not completed on time

Team approves too many deliverables; poor resource planning; poor benchmarking and feasibility causes team to believe they have the resources to complete a task

3 3 9

Focus on main goals of project, discuss, research, and prove feasibility of optional functionality. Discuss goals of project with guide and experts to determine feasibility and likelihood of success. Drop dead date for deliverable list is at system design review (Friday Week 5)

Team Lead, Engineering Leads

5

Difficulty getting electronics small enough for hearing aid

Prototype is larger then originally intended

Components chosen too large, not enough space left for electronics in main hearing aid shell. System integration not thought of before mechanical and electrical systems are built

3 3 9Keep small form factor in mind when choosing technologies and functionality

Lead Electrical Engineer / System Integration Engineer

10

No experience/expertise with ON Semi chip DSP Hybrid chip

If chosen, could run out of time, not have a happy customer, potential product failure

Too difficult to implement, Run out of time trying to learn new product

3 3 9

Seek advice from experts at ON Semi, Plan for difficult implementation and put a large amount of scheduled time

Lead Electrical Engineer/ Systems Engineer

15

Team member feels overloaded with work from MSD

team loses support and quality of work from stressed team member. team member loses motivation to work for the team

Team member volunteers for too many projects; unbalances work assignments; team member is under qualified for assigned tasks and does not seek necessary support (or vocalize need for support)

3 3 9

team manager should monitor work loads of team members to help facilitate an equal distribution of work; individual team members should speak up (to manager or team) if they feel over loaded or that the work is not equally divided among qualified members

team members (and team manager)

Backup

MatLab 1.11.13Code Overview: amplifies sound and reduces noise for a patient with “ski-slope” hearing loss

Frequency Shaper:

Breaks hearing loss into piecewise functions and calculates the required gain for each section

Applies Fourier Transform on the input signal, and multiplies transformed signal by the required gain function

The Inverse Fourier Transform of the signal converts signal back to the time domain.

Amplitude Shaper:

Output signal is inputted into an amplitude shaper to remove noise and confirms signal is in acceptable (not harmful) range.

Types of Ear Molds 1.9.13

Oticon Intiga Hearing aid with “dome” style earmold

Oticon DigiFocus II Hearing aid with “custom” style earmold

Motorola HK200 Bluetooth Headset, “dome” style earmold

Customer Needs 1.11.13Customer Need Rank Description

CN1 9 The device amplifies sound

CN2 9 The device fits most adult ears ages 15-25years

CN3 9 The device does not draw attention to the user as a hard of hearing individual

CN4 9The device supports an active lifestyle (stays on the ear during everyday activities and light activities)

CN5 9 The device includes a way for the user to adjust the volume while on the ear

CN6 9 The device is safe to use

CN7 9 The device is rechargeable by computer USB port

CN8 3 The power in the earpiece should lasts at least 48 non-continuous hours

CN9 3 The device interfaces with a standard tube and ear mold

CN10 3 The weight of the device is similar to existing earpieces

CN11 3 The device is comfortable to wear

CN12 3 The device does not generate excessive heat during use or charging

CN13 1The device includes an additional method for toggling between functions (for later use to switch between programs or turn on Bluetooth, etc.)

CN14 1 The device has a cost similar to current devices when in production

CN15 0 Optional: The device communicates with a cell phone or music player by Bluetooth

CN16 0 Optional: The device has noise cancellation capabilities

Specifications 1.11.13Spec # Source Specification Direction Units of measure Marginal Ideal Notes DRI

S1 CN1 Lowest level of sound detected min dB <60 <30 lowest range of normal hearing EE

S2 CN1 Frequencies amplified max Hz 300-7000 85-8000marginal values are those used in

radio, 85 is lowest male voiceEE

S3 CN1, CN6 Maximum amplification target dB 85-95 90 max considered safe EE

S4 CN5 Levels of volume adjustment max levels 5 20 adjusted in steps or continuous EE

S5 CN7 Time to charge earpiece min minutes <60 <30 EE

S7 CN7 Connects to standard USB 2.0 computer port target yes/no yes/no yes EE

S8 CN11, CN12Maximum temperature at outside surface of

devicemin oF body temp + 10 body temp MEEE

S9CN2, CN4,

CN11Range of adult ear size accommodated max percentile 25th to 75th

10th to 90th

ISE

S10CN4, CN6,

CN10, CN11Weight of earpiece min g <15 <12

marginal values will depend on ergonomic info

ISE

S12 CN8 Earpiece battery life at maximum amplification max hours >16 >48 EE

S14 CN3Percent of serveyed people who identify a

picture of the device as something other than a hearing aid.

max percent >60 >80team should conduct surveys (at

imagine RIT? thoughts?)ID

S15 CN3Percent of surveyed hard of hearing people who prefer the form of the new device to standard

behind the ear hearing aidsmax percent >50 >75 team should conduct surveys ID

S16 CN3Percent of surveyed hearing people who would use the device for Bluetooth or music listening

max percent >50 >70 team should conduct surveys ID

S17 CN11Percent of surveyed people who feel the device

is comfortable to wearmax percent >60 >80 team should conduct surveys ID

S18 CN9 Attaches to a standard ear tube and ear mold yes/no yes/no yes yes maybe should interview

audiologist for final decisionID

S19 CN14 Manufactured cost (estimated) min $ <2000 <1000not as important in first round of

prototyping, but should be considered

ISE

User Interface

Logic Board

Enclosure

Dummy

Ear moldSpeaker

MicrophoneUSB

Battery

System Architecture (Physical) 1.11.13

Ear Tube