High Frequency Strobe Light to View Vocal Cord Vibration

1
High Frequency Strobe Light to View Vocal Cord
Vibration

• Team Members Paul Heideman
• Chris Valley
• Clients Dr. Diane Bless
• Dr. Doug Montequin
• Advisor Willis Tompkins

2
Overview

• Introduction to Stroboscopy
• Problem Statement
• Design Specifications
• Acoustic Impedance
• Alternate Designs
• Final Design
• Design Matrix
• Future Work

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Introduction to Stroboscopy

• Used to diagnose laryngeal diseases and damage
• Stroboscope used to view vocal cord vibration in
  slow motion
• Frequency of strobe light is adjusted according
  to vocal cord vibration frequency

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Introduction to Stroboscopy

• Strobe firing at same frequency as
  vibrationimage is viewed as not moving
• Strobe frequency changed slightly to view
  vibration in slow motion.
• Uses Claude Shannons principle of alias frequency

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Problem Statement

• Currently used model
• Kay RLS Videostroboscopy System Model RLS 9100
• Large and not easily moveable
• Produces significant amounts of noise
• The goals of the project
• Design a self-standing stroboscope system
• Reduce noise
• Smaller, portable design

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Design Specifications

• Self-standing stroboscope system
• Strobe frequency range 50 500 Hz
• Accurate to 1Hz
• 300 Watt Xenon light source
• Low heat generation
• Portable (.5m wide x .3m tall x .7m deep)
• Acoustically sound

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Acoustic Impedance

• Important in determining the ability of a medium
  to absorb sound
• Dependent on
• Density of the medium (?)
• Velocity of sound in medium (V)
• Z ?V 1kg/m2s 1MRayl
• Energy loss between media
• Direct contact between media allows more energy
  transfer
• Air gap reduces contact and energy transfer

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Alternate Designs Design 1

• Plexiglas case (0.5cm thick)
• Foam insulation to prevent sound escape
• Weight 26.8 lbs
• Acoustic impedance
• Plexiglas 3.1 kg/m2s
• Cost estimate 50

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Alternate Designs Design 2

• Steel case (0.2 cm thick)
• Weight 49 lbs
• Acoustic impedance
• Steel 46 kg/m2s
• No foam insulation
• Cost estimate 42

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Final Design

• Aluminum case (0.2cm thick)
• Foam insulation
• Lining inside of case (air gap)
• Surrounding strobe light (heat resistant)
• Weight 28.5 lbs
• Acoustic impedance
• Aluminum 17 kg/m2s
• Cost estimate 68

Circuitry
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Design Matrix
44
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Future Work

• Collaborate with group to determine optimal
  design
• Develop finalized drawings with circuitry and
  strobe light
• Create prototype
• Test prototype
• Acoustic impedance
• Strobe frequency range
• Accuracy

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Questions?
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References

• Kay Elemetrics. http//www.kayelemetrics.com
• UT Encyclopedia acoustic impedance.
  http//www.ndt.net/article/az/ut/aim.htm
• United States Patent and Trademark Office,
  http//www.uspto.org
• Acoustic Impedance. NDT Resource Center.
  http//www.ndt- ed.org/EducationResources/Communi
  tyCollege/Ultr asonics/Physics/acousticimpedance.h
  tm
• Velocity and Acoustic Impedance. Stroud
  Systems, Inc. http//www.stroudsystems.com/veloc
  ity_and_acoustic
• impedance_.htm
• Custom Audio Designs. Soundproofing materials.
• http//www.customaudio.freeserve.co.uk/index.htm