The Sound Sense Vibe

1. The Sound Sense Vibe

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

3. Motivation for project • ~ 6.5 million deaf people in North America. • Strong market for solutions. • Improving safety of the deaf via environmental awareness

4. Roles in project JOHNSON PATRICK MIKE

5. 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

6. 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

7. MIKE • Design and testing of the amp circuit • Soldering of the Pulse Width Modulation (PWM) driver circuit • Post mortem • Half of presentation

8. System Overview The Sound Sense Vibe consists of four major components: • Microphone array • Signal Conditioning Unit • Microcontroller & Software • Vibrating motor array

9. 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

10. High level system design

11. Signal Acquisition • Four unidirectional microphones • Noise filtering • Pre-Amplification • Output signal 0.7 V

12. 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

13. 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

14. 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.

15. Business case • Competition • Cost • Market

16. Competition • Cochlear implants • Hearing Aids • Alert Devices • Multi-Purpose Alert Devices

17. 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 • Mobile Disadvantages: • Very expensive ($60,000+). • Requires rehab to refamiliarize user with sounds • Cannot fully reproduce sounds • Only some deaf people are suitable candidates.

18. 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+)

19. 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

20. 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

21. 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

22. 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.)

23. Project Details Project Budget: • Stayed fairly close to original budget • Amplifier stages were not foreseen

24. Schedule

25. What Was Learned • Plan Carefully • Test early and frequently • Integration never works the first time • Even simple signal processing can be difficult

26. Future Work • Add calibration UI • Better positional performance • Miniaturization • Better armband for comfort and feedback prevention

27. 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

28. Questions