Tactile Auditory Sensory Substitution

1
Tactile Auditory Sensory Substitution

• Jimmy Fong , Jack Page, Becky Jones, Ryan Thome,
  and Matt Valaskey
• Client Veronica H. Heide, Au.D.
  Advisor Mitchell E. Tyler

Device Placement-Behind Ear
1
-Point discrimination test on that area-Tactors 1
and 2 are on the mastoid process 30 mm apart
-Tactors 2 and 3 are 25 mm apart -Tactors 3 and
4 are on the skin below the mastoid process and
are 30 mm apart -The distances are based on a
two-point discrimination test
Abstract
High frequency hearing loss is a problem common
among people of all age groups. People who
suffer from this type of hearing loss often lose
the ability to hear certain consonant sounds.
The goal of this project is to replace the
missing high frequency information using sensory
substitution, a technique for presenting
environmental information missing in one sensory
modality to another.
Design Overview
Device layout
Attachment Considerations

• 1) Long or short term Adhesive
• Made for direct skin application
• Comfortable, easy to apply
• 2) A hook or headband apparatus

-Remove without skin trauma -Resistant to dirt
and moisture -Excellent adhesion to skin
Sound Processing
Channel to Frequency Breakdown
Sixty Fifty
1 1.6-2.0 kHz p, i, m 2 2.0-3.0 kHz ch,
sh 3 3.0-3.5 kHz ch, f 4 4.5-8.0 kHz s, th

• Runs on two 9 V batteries
• Current draw 150 mA
• Expected battery life 12 hr

Costs Circuit Components 10.16 Roadie Sound
Card 49.99 Motors 15.96 Attachment 2.00
Total 78.11
-Normal hearing 50 20,000 Hz -High-frequency
hearing loss Above 1,000 Hz is
lost -Categorized as sensorineural hearing
loss -Loss of ability to hear certain high
frequency consonants
Circuit Design
-Observe vibration pattern of specific words and
consonant sounds -Pairs of words that can be
distinguished with device Sixty versus
Fifty Kit and Tick Shirt versus
Church Sit and Tip Kite and Tied Sob
versus Shop

• Circuit schematic for each audio channel
• - 1st Stage Amplifies signal with a gain of
  50
• 2nd Stage Comparator that saturates at 9 V when
  
• signal gt 1 V
• - 3rd Stage Inverting summer that adds a -9 V
  offset and inverts signal
• 4th Stage High input impedance buffer
• 5th Stage 555 timer in monostable configuration
  to provide a square wave voltage to the
  motor

-Develop system for training with device -Test
efficacy of device on human subjects -Implement
real-time sound processing -Further testing of
tactile placement area -Miniaturize device
Acknowledgements
We would like to thank Dr. Veronica Heide and
Prof. Mitch Tyler for their patient guidance as
well as Prof. L. Burke ONeal and Amit Nimunkar
for their circuit expertise.
Vibrotactile Motors
Vibrating Motor
References
-12mm diameter, 3.4mm thick -1G vibration -12,000
RPM -Requires lt 3V and lt 50mA

• Krames Communications. (1995). Hearing Aids.
  Brochure. San Bruno, CA.
• Audiological Engineering Corp. (n.d.) Tactaid 7.
  Retrieved 29 September, 2006 from
  http//www.tactaid.com/tactaid71.html.
• Kanyo, M. et al. 2005. A Tactile Synthesis Method
  Using Multiple Frequency Vibrations for
  Representing Virtual Touch. IEEE/RSJ. p 1121
  1127.