Controllable Infrasound Source Doug Fox Daxton Ruger Jerad Wunder - - PowerPoint PPT Presentation

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Controllable Infrasound Source Doug Fox Daxton Ruger Jerad Wunder - - PowerPoint PPT Presentation

Jun 29, 2023 587 likes •874 views

Controllable Infrasound Source Doug Fox Daxton Ruger Jerad Wunder What is Infrasound? Frequencies below 20hz Human hearing lower limit - 12hz Common sources Helicopters Elephant Vocalizations Earthquakes

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Controllable Infrasound Source

Doug Fox Daxton Ruger Jerad Wunder

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What is Infrasound?

  • Frequencies below

20hz

  • Human hearing

lower limit - 12hz

  • Common sources

○ Helicopters ○ Elephant Vocalizations ○ Earthquakes

  • Can be detected over

large distances

http://people.ece.cornell.edu/land/courses/ece5030/FinalProjects/s2014/kkp37_rjs483/kkp37_rjs483/AudioGram.html

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Infrasonic Detection

  • Dr. Brian Elbing

○ Research in infrasound possibly emitted by a tornado

  • Infrasound microphone array located in the North Campus Lab area
  • Dr. Brian Elbing,

Oklahoma State University

https://www.wired.com/story/a-tornados-secret-sounds/

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Objective

  • To design and construct a compact, mobile

device capable of generating controllable infrasonic tones. ○ Used to calibrate infrasonic microphone array to ensure accuracy of collected data

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Subwoofers

  • Coil in magnetic field - current direction determines

cone movement direction

  • Placed in enclosure - separates + and - pressure waves
  • Not efficient below 20Hz
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Rotary Subwoofers

  • Efficient output from <1Hz to 20Hz
  • Fan motor spins blades
  • Helicopter rotor head actuates blade pitch

○ Controlled by subwoofer motor

  • Baffle separates pressure waves
  • Relatively compact

Eminent Technologies TRW-17

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Final Design

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Final Design

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Final Design

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Final Design

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Bill of Materials

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Sourced Materials

Subwoofer - Kicker CompR 12”

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Sourced Materials

Amplifier power supply - 75A DC power supply Subwoofer amplifier - Modified Kicker CXA1200.1

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Sourced Materials

R/C helicopter rotorhead

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Sourced Materials

3-phase A/C motor VFD Controller

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Design Needs Frame

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Design Needs Blade and adapter

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Design Needs Coupling shaft

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Design Needs Motor stand

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Design Needs Swashplate adapter

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Design Alternatives Blade

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Design Alternatives Shaft

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Design Alternatives Blade adapter

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Small building used as enclosure ○ “Infinite baffle” Frequency response (SPL) recorded 4- 20Hz ○ Larson Davis 831 microphone

Test Setup .

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Results

  • Microphone

~20ft axial distance

  • Amp gain

halfway

  • Motor @ 300

rpm

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References

[1] Olson, Harry F, (1967). “Music, Physics and Engineering,” Dover Publications, 1967. ISBN 0-486-21769-8.

[2] M. Simon, “A Tornado's Secret Sounds Could Reveal Where It'll Strike,” Wired, 08-May-2018. [Online]. Available: https://www.wired.com/story/a-tornados-secret-sounds/. [Accessed: 03-Dec-2018].