The Sound Sense Vibe

Outline Motivation for project Roles in project System Overview High level system design Business Case Project Details What Was Learned Future Work Conclusions Questions

Motivation for project

~ 6.5 million deaf people in North America.

Strong market for solutions.

Improving safety of the deaf via environmental awareness

Roles in project

JOHNSON

PATRICK

MIKE

JOHNSON

Pre-amplifier soldering and modification Revised design of signal conditioning amplifier PWM motor driver design Microphone “Shot Gun” enclosure Vibrating motors enclosure Hardware testing and wiring

Signal cable construction

PWM ISR instruction code Draft of A/D conversion ISR instruction code

PATRICK

Majority of Software A/D Capture & Summation ISR Main Program Loop Some PWM ISR Work

Amplification Stage Requirements & Testing Armband concept and creation High-level project design, requirements and testing

MIKE

Design and testing of the amp circuit Soldering of the Pulse Width Modulation

(PWM) driver circuit Post mortem Half of presentation

System Overview

The Sound Sense Vibe consists of four major components:

Microphone array Signal Conditioning Unit Microcontroller & Software Vibrating motor array

System overview

Microphones capture the audio

Signal Conditioning Circuit (pre-amp and amp) prepares signal for A/D converter

Microcontroller A/D converter digitizes signal

Software determines whether motor should be activated or not

Microcontroller Output port activates/deactivates motor

High level system design

Microphone A Preamp A Amplifier AMicro Controller A/D Channel A

PWM Motor A Vibrating Motor A

Microphone B Preamp B Amplifier BMicro Controller A/D Channel B

PWM Motor B Vibrating Motor B

Microphone C Preamp C Amplifier CMicro Controller A/D Channel C

PWM Motor C Vibrating Motor C

Microphone D Preamp D Amplifier DMicro Controller A/D Channel D

PWM Motor D Vibrating Motor D

Signal Aquisition Signal Conditioning Signal Processing Actuator Interface

Signal Acquisition

Four unidirectional microphones Noise filtering Pre-Amplification Output signal 0.7 V

Signal Conditioning

Amplification Output is from -2.5V to 2.5V

Level shifting Output is from 0 V to 5 V

Variable resistor Variable DC offset Enhanced stability Ensures proper output shifting

Signal Processing

10 KHz sampling rate Approximate signal

integration to find signal power for a fixed window

Use this power and a threshold to determine if a motor should be on/off during window period

Actuator Interface

Four vibrating motors Pulse Width Modulation

(PWM) driver. PWM signals drive transistor

into saturation Power to motor controlled by

pulse bandwidth Current limiting resistor Diode preventing startup

spikes.

PWM Input

M

Electric Motor

Collector Current Limit Resistor

+Vcc

GND

Surge Protection Diode

Business case

Competition

Cost

Market

Competition

Cochlear implants

Hearing Aids

Alert Devices

Multi-Purpose Alert Devices

Cochlear implants

Direct connection between nerve endings in the brain and the hearing aid.

Advantages: Users can regain the ability to

understand speech Device completely bypasses possibly

damaged inner ear and cochlea works Even in cases of profound

deafness MobileDisadvantages: Very expensive ($60,000+). Requires rehab to refamiliarize user

with sounds Cannot fully reproduce sounds Only some deaf people are suitable

candidates.

Hearing Aids

Amplifies sound for the ear most common device for the hearing

impaired.

Advantages: compensates for the gradual decay of

hearing widely available Mobile

Disadvantages: Cannot help those with profound

deafness Still moderately expensive ($300+)

Alert Devices

Alarm triggers receiver which notifies user via vibration or lights.

Advantages: Fairly Cheap Ensures the user is alerted to

specific events

Disadvantages: Non-mobile (limited to the

domicile) Requires replacement of existing

doorbells/fire alarms/alarm clocks

Multi-Purpose Alert Devices

Programmable to recognize certain noises and alerts user.

Advantages: Priced between hearing aids and general alert devices Can be trained to recognize events for alerting Mobile

Disadvantages: Rare (not available anywhere on market in large volumes) Can be difficult to setup

Cost

The total cost of all components in our project was ~$300 (see budget for more info)

Final miniaturized version should still be sub $500

Comparable to a hearing aid

Market

Our product fits into a unique area not covered by any competing products

TARGET: profoundly deaf not suitable for hearing aids cannot afford cochlear implants not suitable patients for the

surgery. Workers in high noise

environments (Airport tarmac workers, etc.)

Project Details

Project Budget: Stayed fairly close to

original budget Amplifier stages were

not foreseen

Item Estimated Actual

Uni-Directional Microphones

$30 $16

Pre-Amplifier N/A $20

Signal Amplifier N/A $10

Vibrating Motor $20 $18

68HC11 Micro-controller DEVL. Board

Free Free

Arm Attachment $20 $16

Misc. Expenses (Shipping etc)

N/A $10

Total: $70 $90

Schedule

What Was Learned

Plan Carefully Test early and

frequently Integration never

works the first time Even simple signal

processing can be difficult

Future Work

Add calibration UI Better positional

performance Miniaturization Better armband for

comfort and feedback prevention

Conclusions

Accomplished a lot in a small amount of time Heavy limitations in terms of time and resources Good proof of concept device performs what we

hoped it would Project provided a good combination of

disciplines: electronics, real-time embedded programming, signal processing, usability

Questions