DHA D irectional H earing A id
description
Transcript of DHA D irectional H earing A id
![Page 1: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/1.jpg)
![Page 2: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/2.jpg)
Team Members:Noah Van FossanShareen HossainDeepthi ChandraChristina ClemenzLaura Hanley
Advisors:Prof. Mark BellProf. Carla Zoltowski
Project Partner: Prof. Robert Novak
DHA Directional Hearing Aid
![Page 3: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/3.jpg)
To design and develop an inexpensive hearing aid that will cancel out background noise so that a person with a hearing impairment can carry out a conversation in a noisy environment.
Four microphones forming a linear array are embedded on an eyeglass frame and connected to a circuit which is is largely responsible for the noise cancellation effect.
Project Goal
Overview
DHA Directional Hearing Aid
![Page 4: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/4.jpg)
All microphones must be separated by a fixed distance to produce maximum cancellation of unwanted signals.Input and summing stages must have similar impedances so they do not cause a phase shift inside of the circuit.Having the microphones spaced four centimeters apart increases directionality for high frequencies because of their short wavelength. Low frequencies would require a larger spacing between microphones.
Microphone Array Theory
DHA Directional Hearing Aid
![Page 5: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/5.jpg)
DHA Directional Hearing Aid
The frequency range is from 500Hz to 5.5KHz.
Adjustable lower frequency cutoff switch- 500Hz to 1.5KHz
• Human ear loses high frequency first so more emphasis must be placed upon the base.
Cascading low and high pass filters create the desired frequency range.
Frequency Range Theory
![Page 6: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/6.jpg)
DHA Directional Hearing Aid
• new circuit built, in testing phase
• Increased gain to 45 dB
• Finished auto-off design
• debugging circuit antenna problem
• redesigning the virtual ground
Semester Accomplishments
![Page 7: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/7.jpg)
DHA Directional Hearing Aid
Current Circuit
![Page 8: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/8.jpg)
DHA Directional Hearing Aid
Summing amplifier and High pass stage. • Directionality and low frequency cutoff
occur in this stage
Low pass Stage • High frequencies are cutoff at this
stage.
Gain Stage • The output signal is amplified during
this phase.
![Page 9: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/9.jpg)
DHA Directional Hearing Aid
• Antenna Problem Input
• Voltage leads act as an antenna and is bringing in a frequency of 33KHz
Debugging Process
![Page 10: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/10.jpg)
DHA Directional Hearing Aid
Flaws in Virtual Ground Design
• Large current cannot be drawn from current design
• Gain loss occurs when a load resistance (headphones) is attached
Debugging Process
Current Virtual Ground
![Page 11: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/11.jpg)
DHA Directional Hearing Aid
Solution for antenna problem. • Relocate circuit to protoboard.
New virtual ground design
Proposed Solutions
![Page 12: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/12.jpg)
DHA Directional Hearing Aid
Implementation of auto-off featureFuture Circuit Design
![Page 13: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/13.jpg)
Producing the ProductFuture Semester Goals
DHA Directional Hearing Aid
1. Build Prototype of new circuit
2. Perform various tests
Post prototype lab test
Human subject test
3. Deliver the product
![Page 14: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/14.jpg)
![Page 15: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/15.jpg)
![Page 16: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/16.jpg)
![Page 17: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/17.jpg)
![Page 18: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/18.jpg)
Presented by:Maggie ZhuJason KaedingGreg MooreGuy BarcelonaJamy Archer
Project Partner – Dr. Robert Novak,M. D. Steer Audiology Clinic at Purdue
SEM Sound Exposure Meter
![Page 19: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/19.jpg)
Project Objectives Alert user when
noise level could cause hearing damage
Easy to use, easy to understand
Small size (i.e. a pager)
![Page 20: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/20.jpg)
Desired Functionality Instantaneous indicator
• Current noise level > 85dBA
Average level indicator• Avg. noise level for 1 min. > 85dBA
Impulse noise indicator• Avg. frequency of impulses in excess of
110dBA > 1 per 3 sec.
![Page 21: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/21.jpg)
Overview ofCircuit Design
Instantaneous IndicatorAverage Level Indicator
Impulse Noise Indicator
![Page 22: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/22.jpg)
SemesterAccomplishments
Evaluated and consolidated impulse noise indicator section
Redesigned A-weighting filter
Created test plan
![Page 23: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/23.jpg)
Impulse Noise Indicator
Tested current hardware configurations
Consolidated counters and comparator into PLD
Added continuous testing functionality.
![Page 24: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/24.jpg)
Filter Design Goal: accurately model A-weighting
transfer function
![Page 25: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/25.jpg)
Filter Design Design completed
•Three sections
• Each realizes one part of the transfer curve
• Used active Sallen and Key circuits
•SPICE simulation
• Max. deviation < 0.6dB
![Page 26: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/26.jpg)
Test Plan
Designed for the overall circuit
Includes a standardized procedure and safety concerns
Compares circuit response to the response of Sound Level Meter
![Page 27: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/27.jpg)
Future Plans
Individually test each functional block
Fine tune reference voltages in comparators
Complete new circuit diagram
Implement test plan for whole circuit
![Page 28: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/28.jpg)
![Page 29: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/29.jpg)
Tim ChuahJason FluckeyValerie Lamott
Erica LuteNate Miller
Project Partner – Dr. Robert Novak,M. D. Steer Audiology Clinic at Purdue
VLM Voice Level Meter
![Page 30: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/30.jpg)
Problem Identification
Audiology Clinic needs a visual means of measuring speech volume.
Existing device, Spright II, has been discontinued.
![Page 31: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/31.jpg)
Improvements
Existing device is not very accurate. Longer cord or battery operated. Improve LED display readability.
![Page 32: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/32.jpg)
Design Concept
5 10-segment LED bar graphs
Range of 40-89dB
![Page 33: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/33.jpg)
Block Diagram
![Page 34: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/34.jpg)
Circuit Diagram
![Page 35: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/35.jpg)
Project Status
Low pass filter has been built and it works.
Second low pass filter was designed and it also has been built and works.
Log amp has been built and it works. Microphone through log amp
working together
![Page 36: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/36.jpg)
Future Plans
Add potentiometers Work on driver chips Work on casing
![Page 37: DHA D irectional H earing A id](https://reader036.fdocuments.in/reader036/viewer/2022062309/56815827550346895dc58b86/html5/thumbnails/37.jpg)