troy owens, john trytko, adam ornstein, dmitriy polyakov, michael tanksalvala
Post on 19-Dec-2015
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OPEN-ATMOSPHERE PHASE-SHIFT CAVITY RINGDOWN INSTRUMENT
NOAA’S ARK
Troy Owens, John Trytko, Adam Ornstein, Dmitriy Polyakov, Michael Tanksalvala
CONCEPTUAL BACKGROUND
System measures the phase shift of light to determine the concentration of particles in the airLight accumulates a media-dependent phase shift as it
resonates in the cavityHigher concentration of particles induce a larger phase shift
This is used in conjunction with other instruments to compute specific concentrations of various aerosols
John Dmitriy Michael Adam Troy
Laser Controller Laser
PhotodiodeBeam Splitter
Ringdown Cavity
Phase Shift Detector
John Dmitriy Michael Adam Troy
Kebabian, Paul L., Scott C. Herndon, and Andrew Freedman. "Detection of Nitrogen Dioxide by Cavity Attenuated Phase Shift Spectroscopy." Analytical Chemistry 77.2 (2005): 725. Print.
APPLICATIONS AND ADVANTAGES
Applications:Reference for specialized particle-detecting systemsMeasure aerosol content in open airAir quality
Advantages:Compact and portableTurn-key (no knowledge of instrument required)Self-aligning opticsAutonomous data collection
John Dmitriy Michael Adam Troy
GOALS
Low PriorityAchieve awesomeness – easy with lasersDetect phase shift on optical breadboard
MediumAutomated laser alignment systemData storageNo use of external lab equipment
HighCompact (backpack size) systemEntirely autonomous (after easy startup)
John Dmitriy Michael Adam Troy
FUNCTIONAL OUTLINE OF APPROACH
Pow
er
Battery
Optics
Operating System
CMOS Camera
Alignmentμ-Controller
Photo DiodeA/D
SD CardUserI/O
Clock
John Dmitriy Michael Adam Troy
CONSTRAINTS
Successful signal detection Cavity must establish and maintain an
optical standing wave Mechanical stability Meaningful output from photodiode Final output in specified file format Time!!!
John Dmitriy Michael Adam Troy
SAFETY AND ENVIRONMENTAL IMPACT Environmental impact
Difficult to dispose of partsBeam doesn’t interfere with the environment
SafetyLaser can damage eyeLow power laser
John Dmitriy Michael Adam Troy
LASER SAFETY
Class IIIa-IIIb (continuous wave, 1 to 20 mW)Visible wavelengths (350 – 800 nm)Low power/area (< 2 mW/cm2)
HazardsCorneal damage only (safe exposure time is
roughly .25 seconds)Non-permanent retinal damage if viewed for 1 to
2 seconds, permanent viewed for longerDo not look into the laser
John Dmitriy Michael Adam Troy
MANUFACTURABILITY AND SUSTAINABILITY
Manufacturability Intended for singular creationMass production unlikelyEasily portable
SustainabilityLow power consumptionDurable parts and reliable electronics
John Dmitriy Michael Adam Troy
THE OPTICS
Laser controller (enabling phase detection) Concave mirrors for the cavity Controllable mirror mounts (enabling
feedback control) Beam-splitter Photodiode (signal measurement) CMOS Camera (sensor for feedback)
John Dmitriy Michael Adam Troy
Laser Controller Laser
PhotodiodeBeam Splitter
Ringdown Cavity
Phase Shift Detector
John Dmitriy Michael Adam Troy
Image obtained from: http://www.chem.ualberta.ca/~xu/research/crds.htm
ACTIVE FEEDBACK/ALIGNMENT
Objective: Maintain maximum signal power Keeps beam pointed at photodiode using
PID Controller If signal is lost, methodically scans over area
to try to find it Concave mirrors provide small amount of
passive beam alignment
John Dmitriy Michael Adam Troy
CONTROLLABLE MIRROR MOUNTS
Constructed from normal mirror mounts and (disassembled) piezoelectric buzzers
Piezoelectric ceramic expands when voltage is applied
John Dmitriy Michael Adam Troy
Laser Controller Laser
Beam Splitter
Alignment System
CMOS Camera
Micro-Controller
John Dmitriy Michael Adam Troy
CONSTRUCTION AND TESTING
Create circuit to connect camera to computerHelps for debugging during and after
developmentEnables good capstone demo
Add controllable mirror and microcontrollerBeam-steering functionalitySoftware-based PID signal maximizationSignal-finding
Add second mirror and integrate it into PID
John Dmitriy Michael Adam Troy
OBSTACLES
Processing TimeCamera can output millions of datapoints20 MHz processor
Number of Cameras Signal strength at Camera Contingency plan: Using concave mirrors
provides a self-aligning force, so even without active feedback, measurements can be made
John Dmitriy Michael Adam Troy
OPERATING SYSTEM AND μC
SD CardStorage of phase, timestamp, and “valid bit”OS Storage (cold-start)
ClockMicrocontroller oscillatorTimestamps
John Dmitriy Michael Adam Troy
Operating System
Battery
UserInterface
HardwareClock
Micro-Controller
Phase Shift Detector
Solid StateDrive
SD
John Dmitriy Michael Adam Troy
OPERATING SYSTEM AND μC
SD CardStorage of phase, timestamp, and “valid bit”OS Storage (cold-start)
ClockMicrocontroller oscillatorTimestamps
John Dmitriy Michael Adam Troy
OS I/O AND FUNCTIONS
ADC SD Card Time I/O
Data Processing Time ManagementData Formatting
OS / μC
John Dmitriy Michael Adam Troy
DIVISION OF LABORTask Primary Secondary
OS Design and Data Storage Adam Michael
Mechanical Structure/Alignment Dmitriy John
Control Systems Michael Adam
Power system Troy
Board Layout/Construction John, Adam Troy, Michael
Optical Construction and Detection
John Dmitriy
Design Documentation All
Chief Financial Officer (CFO) Michael
John Dmitriy Michael Adam Troy
BUDGET Equipment Estimated Price
Laser Controller Borrowed from NOAA
Laser Borrowed from NOAA
Mirror Mounts/Mirrors Borrowed from NOAA
Photodiode $20
1-2 x Beam-Sampler 1-2 x $60
MSP430 $40
ATMega328 $5
16-Pin AVR Development Board $20
1-2 x CMOS Camera 1-2 x $35
1-2 x PCB 1-2 x $60
Piezoelectric Buzzer $5
Other $100
TOTAL $345 - $500
John Dmitriy Michael Adam Troy
FUNDING AND GRANTS
NOAAProviding optical parts (mirrors, mounts,
laser controller, optical breadboard, laser)Will keep the prototype upon completion
UROP Funding (Pending)Up to $1000 fundingRequires a report upon completion
John Dmitriy Michael Adam Troy
POTENTIAL ISSUES / CONTINGENCY PLAN Not able to integrate OS with Optics
Will demonstrate the systems separately at Expo
Not able to construct casing for a portable deviceDemonstrate the project on separate
breadboards at Expo
John Dmitriy Michael Adam Troy