Earthquake Detector Using the Michelson InterferometerEarthquake Detector Using the Michelson Interferometer
The Mid-South Annual Engineering and Sciences ConferenceThe Mid-South Annual Engineering and Sciences ConferenceMAESC 2006MAESC 2006
Memphis, TennesseeMemphis, Tennessee
Haoyan Bill LanHaoyan Bill Lan
March 31, 2006March 31, 2006
Deep undergroundEvery Day
America's most destructive earthquakes since America's most destructive earthquakes since
the turn of the 20th century:the turn of the 20th century:
Last Decade
People Are at RiskPeople Are at RiskResearches need to be done Researches need to be done
there are there are 70,00070,000 buildings in state of buildings in state of California alone that could sustain major California alone that could sustain major quake damage quake damage
Experts predict there will be a major Experts predict there will be a major earthquake in state of California earthquake in state of California before before year 2024 year 2024
For those who lives thereFor those who lives there
It would be nice….It would be nice….
If……If……
Earthquake Detector PrototypeEarthquake Detector Prototype
Michelson Interferometer
Optical Power Meter
Analog to Digital Interfaceand LED Displays
UP3 Board with aCyclone Microprocessor
Project Concept Project Concept Michelson Interferometer
Light Intensity Measuring Device
Analog to digital interface
Major part of the project
Central processing unit UP3 board (Quartus II)
Alarm System and back up power supply
4 Digits7-Segment LED Display
Screen Matrix for Different NeedsScreen Matrix for Different Needs
3D View of an Interferometer3D View of an Interferometer
Sensor of Light Intensity Measuring Device
Move Mirror#1 to cause the fringe movement
He Ne Laser Beam Generator
Beam Splitter
Mirror#2 Stationary
Bright Fringe
Dark Fringe
Dispersion Lens
How does it work?How does it work?Mirror#2 Stationary
Mirror#1 Moving
Bright Fringe
Dark Fringe
Sensor of Optical Power Meter
Movement of Mirror#1 generates fringe movement
Dial for Moving Mirror
Need fringes number to calculate the Need fringes number to calculate the wavelength wavelength
Fringe movements not be counted using Fringe movements not be counted using naked eyesnaked eyes
The sinusoidal wave has a frequency The sinusoidal wave has a frequency approx. at 100Hzapprox. at 100Hz
The way to measure the spectral of the light The way to measure the spectral of the light is is
where d is the distance M1 has been moved where d is the distance M1 has been moved and n is the number of the fringes and and n is the number of the fringes and Lambda is the wavelength of the laser beam. Lambda is the wavelength of the laser beam.
n
d
2
How does this work?How does this work?
a single tap on the table will cause a single tap on the table will cause rapid movement of the fringes rapid movement of the fringes
this property can be used to this property can be used to detect a detect a potential earthquakepotential earthquake
Sinusoidal wave from the optical power meter
Output wave form goes into the UP3 board
Offset Voltage
Design of an Analog to Digital InterfaceDesign of an Analog to Digital Interface
Adjustable offset voltage
TTL output
Project Concept Project Concept Michelson Interferometer
Light Intensity Measuring Device
Analog to digital interface
Major part of the project
Central processing unit UP3 board (Quartus II)
Alarm System and back up power supply
4 Digits7-Segment LED Display
Altera UP3 board is setup in the labAltera UP3 board is setup in the lab
Output to 4-digits Displays
Input from Analogto Digital Interface
Microprocessor is Programmed via a PC
Circuit Design using QuartusCircuit Design using Quartus
Input from Analogto Digital Interface
Output of the UnitDigit
Output of the TenthDigit
Output of the Hundredth Digit
Output of the Thousandth Digit
A 74143 chipA 74143 chip
Input
Decade Counter
Decoder
LED Digit DisplaysLED Digit Displays7-Seg LED Display
Prototype TestingPrototype Testing
Simulate an Simulate an earthquakeearthquake
Tester tap table Tester tap table with his/her fingerwith his/her finger
SinceSince
Lambda for a He-Ne laser beam is 632nmLambda for a He-Ne laser beam is 632nmFor each fringes (n=1), we are movingFor each fringes (n=1), we are moving
Theoretically we are detecting vibration on Theoretically we are detecting vibration on 1/3um scale 1/3um scale
Put 1/3um into a prospective scalePut 1/3um into a prospective scale
Vibration of1/3 of this Scale
Human hair avg. 65um in Diameter
Prototype Estimated CostPrototype Estimated Cost
Interferometer $700Interferometer $700
Light intensity detector $150Light intensity detector $150
Quartus II and software $300Quartus II and software $300
Other parts and hardware $50Other parts and hardware $50
Total cost $1200Total cost $1200
Estimated Production CostEstimated Production Cost
Interferometer $100Interferometer $100
Light intensity detector $50Light intensity detector $50
Burn-in Chips $10 Burn-in Chips $10
Other parts and hardware $50Other parts and hardware $50
Total cost ~$210Total cost ~$210
Instead of the $300 UP3 Board
ReferencesReferences
http://www.3dimagery.com/http://www.3dimagery.com/3dmichelson.html3dmichelson.html
http://www.latimes.com/business/la-me-http://www.latimes.com/business/la-me-quake8sep08,0,3035306.storyquake8sep08,0,3035306.story
http://www.altera.com/education/univ/http://www.altera.com/education/univ/students/unv-students.htmlstudents/unv-students.html
http://www.space.com/scienceastronomy/http://www.space.com/scienceastronomy/astronomy/interferometry_101.htmlastronomy/interferometry_101.html
Questions And Comments?Questions And Comments?
Prototype Testing ContinuesPrototype Testing Continues
Simulation of a Simulation of a fire disasterfire disaster has been conducted has been conducted as wellas well
A pressure changing device has been usedA pressure changing device has been used
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