1. FM Hearing-Aid Device Checkpoint 1
Brian Fang | Robert Johnson | Shoman Kasbekar | Zach Kovar | Arif Moktader

2. The Problem Hearing aid difficulties
How can hearing performance be improved to enable speech distance evaluation?
Project Goal: modify FM radio system in order to maintain a constant signal-to-noise ratio as the distance between the transmitter and receiver changes
Amplification quality must be maintained throughout
Detecting and expressing location of the transmitter relative to the receiver may be secondary function to research and develop
hearing aid user has great difficulty discerning between auditory stimuli at near and far distances, particularly in unstructured settings such as houses.
This project essentially strives to design a better hearing aid
The goal of the project is to modify an FM radio system (wireless microphone) such that the distance between the transmitter and receiver can be detected and expressed to the user while maintaining audio amplification quality.
Detecting and expressing location of the transmitter relative to the receiver may be secondary function to research and develop

3. Last Time Out
Touched base with sponsors - cleared to continue with design plan
Hearing aid company is based in Switzerland, so it took a while to schedule the meeting
Goals are now much clearer - focus on distance
Dr. Anne Marie Tharpe
Dr. Daniel Ashmead
Francois Marquis

4. Design Components Signal Filter Microphone Receiver Hearing Aid
Transmits signal to
Signal Filter
Microphone
Receiver
Transmits filtered signal to
Transmits signal to
Transmits signal to
Transmits distance data to
Hearing Aid
Transmitter
Receives signal from
Detects distance from
Receives filtered signal from
Located close to
Detector
User
Speaker

5. Project Progress Code in development Future Goals MATLAB C
Create a hardware box that implements filters in real time
Will request funding for an Arduino to program and control input sound signals

6. Background Research Intensity loudness changes depending on distance
Inverse relationship, extensively modeled
Frequency
perceived pitch changes depending on relative distance
operates as a cue relative to distance - unusable at short distances
Pinna effect
Binaural
(An Analysis of Cues to Auditory Depth Perception in Free Space)
Physical acoustics reveals a bunch of stimulus correlates of sound source distance. These provide distance information detectable by ear.
Intensity - commonly known, amplitude of sound changes with distance at an inverse relationship. This relationship has been extensively studied and
Frequency - another cue in auditory depth perception, controversy as to how this cue influences distance judgments. Must consider frequency to operate as a cue in one manner at near differences and in another manner at far distances.
Pinna effect
delay from reverberant sound
Binaural
degree of phase difference

7. Basic Design Flowchart
Location Scalars
Reverb
Filtering
Input
Output

8. GANTT Chart

9. Questions?