Earthquake Detector Using the Michelson Interferometer The Mid-South Annual Engineering and Sciences Conference MAESC 2006 Memphis, Tennessee

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Earthquake Detector Using the Michelson
Interferometer The Mid-South Annual
Engineering and Sciences ConferenceMAESC
2006Memphis, Tennessee

• Haoyan Bill Lan
• March 31, 2006

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Every Day
Deep underground
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America's most destructive earthquakes since the
turn of the 20th century
Last Decade
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People Are at RiskResearches need to be done

• there are 70,000 buildings in state of California
  alone that could sustain major quake damage
• Experts predict there will be a major earthquake
  in state of California before year 2024

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• For those who lives there
• It would be nice.
• If

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Earthquake Detector Prototype
Optical Power Meter
Analog to Digital Interface and LED Displays
Michelson Interferometer
UP3 Board with a Cyclone Microprocessor
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Project Concept
Michelson Interferometer
Light Intensity Measuring Device
Analog to digital interface
Major part of the project Central processing
unit UP3 board (Quartus II)
4 Digits 7-Segment LED Display
Alarm System and back up power supply
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Screen Matrix for Different Needs
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3D View of an Interferometer
Sensor of Light Intensity Measuring Device
Bright Fringe
Mirror2 Stationary
Dark Fringe
Beam Splitter
He Ne Laser Beam Generator
Dispersion Lens
Move Mirror1 to cause the fringe movement
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How does it work?
Mirror2 Stationary
Mirror1 Moving
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Bright Fringe
Dark Fringe
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Sensor of Optical Power Meter
Dial for Moving Mirror
Movement of Mirror1 generates fringe movement
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• Need fringes number to calculate the wavelength
• Fringe movements not be counted using naked eyes
• The sinusoidal wave has a frequency approx. at
  100Hz

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• The way to measure the spectral of the light is
• where d is the distance M1 has been moved and n
  is the number of the fringes and Lambda is the
  wavelength of the laser beam.

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How does this work?

• a single tap on the table will cause rapid
  movement of the fringes
• this property can be used to detect a potential
  earthquake

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Sinusoidal wave from the optical power meter
Offset Voltage
Output wave form goes into the UP3 board
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Design of an Analog to Digital Interface
Adjustable offset voltage
TTL output
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Project Concept
Michelson Interferometer
Light Intensity Measuring Device
Analog to digital interface
Major part of the project Central processing
unit UP3 board (Quartus II)
4 Digits 7-Segment LED Display
Alarm System and back up power supply
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Altera UP3 board is setup in the lab
Microprocessor is Programmed via a PC
Input from Analog to Digital Interface
Output to 4-digits Displays
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Circuit Design using Quartus
Output of the Unit Digit
Output of the Tenth Digit
Input from Analog to Digital Interface
Output of the Hundredth Digit
Output of the Thousandth Digit
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A 74143 chip
Decade Counter
Decoder
Input
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LED Digit Displays
7-Seg LED Display
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Prototype Testing

• Simulate an earthquake
• Tester tap table with his/her finger

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• Since

• Lambda for a He-Ne laser beam is 632nm
• For each fringes (n1), we are moving
• Theoretically we are detecting vibration on 1/3um
  scale

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• Put 1/3um into a prospective scale

Human hair avg. 65um in Diameter
Vibration of 1/3 of this Scale
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Prototype Estimated Cost

• Interferometer 700
• Light intensity detector 150
• Quartus II and software 300
• Other parts and hardware 50
• Total cost 1200

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Estimated Production Cost

• Interferometer 100
• Light intensity detector 50
• Burn-in Chips 10
• Other parts and hardware 50
• Total cost 210

Instead of the 300 UP3 Board
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References

• http//www.3dimagery.com/3dmichelson.html
• http//www.latimes.com/business/la-me-quake8sep08,
  0,3035306.story
• http//www.altera.com/education/univ/students/unv-
  students.html
• http//www.space.com/scienceastronomy/astronomy/in
  terferometry_101.html

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Questions And Comments?
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Prototype Testing Continues

• Simulation of a fire disaster has been conducted
  as well
• A pressure changing device has been used