Transcript Troy Owens, John Trytko, Adam Ornstein, Dmitriy Polyakov, Michael Tanksalvala.

Troy Owens, John Trytko, Adam Ornstein, Dmitriy Polyakov, Michael Tanksalvala

System measures the phase shift of light to
determine the concentration of particles in the air
 Light accumulates a media-dependent phase shift as it
resonates in the cavity
 Higher 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
Ringdown
Cavity
Beam
Splitter
Photodiode
Phase Shift
Detector
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.
John Dmitriy Michael Adam Troy

Applications:
 Reference for specialized particle-detecting
systems
 Measure aerosol content in open air
 Air quality

Advantages:

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Compact and portable
Turn-key (no knowledge of instrument required)
Self-aligning optics
Autonomous data collection
John Dmitriy Michael Adam Troy

Low Priority
 Achieve awesomeness – easy with lasers
 Detect phase shift on optical breadboard

Medium
 Automated laser alignment system
 Data storage
 No use of external lab equipment

High
 Compact (backpack size) system
 Entirely autonomous (after easy startup)
John Dmitriy Michael Adam Troy
Power
John Dmitriy Michael Adam Troy
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
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Environmental impact
 Difficult to dispose of parts
 Beam doesn’t interfere with the environment
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Safety
 Laser can damage eye
 Low power laser
John Dmitriy Michael Adam Troy

Class IIIa-IIIb (continuous wave, 1 to 20 mW)
 Visible wavelengths (350 – 800 nm)
 Low power/area (< 2 mW/cm2)

Hazards
 Corneal damage only (safe exposure time is
roughly .25 seconds)
 Non-permanent retinal damage if viewed for 1 to
2 seconds, permanent viewed for longer
 Do not look into the laser
John Dmitriy Michael Adam Troy

Manufacturability
 Intended for singular creation
 Mass production unlikely
 Easily portable

Sustainability
 Low power consumption
 Durable parts and reliable electronics
John Dmitriy Michael Adam Troy
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
Ringdown
Cavity
Beam
Splitter
Phase Shift
Detector
Image obtained from: http://www.chem.ualberta.ca/~xu/research/crds.htm
John Dmitriy Michael Adam Troy
Photodiode
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
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
MicroController
John Dmitriy Michael Adam Troy

Create circuit to connect camera to computer
 Helps for debugging during and after
development
 Enables good capstone demo
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Add controllable mirror and microcontroller
 Beam-steering functionality
 Software-based PID signal maximization
 Signal-finding

Add second mirror and integrate it into PID
John Dmitriy Michael Adam Troy
Laser
Controller
Beam
Splitter
Laser
Alignment
System
John Dmitriy Michael Adam Troy
Photodiode

Processing Time
 Camera can output millions of datapoints
 20 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
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SD Card
 Storage of phase, timestamp, and “valid bit”
 OS Storage (cold-start)

Clock
 Microcontroller oscillator
 Timestamps
John Dmitriy Michael Adam Troy
Battery
Phase Shift
Detector
Hardware
Clock
User
Interface
MicroController
SD
Solid State
Drive
John Dmitriy Michael Adam Troy
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SD Card
 Storage of phase, timestamp, and “valid bit”
 OS Storage (cold-start)

Clock
 Microcontroller oscillator
 Timestamps
John Dmitriy Michael Adam Troy
Data Processing
Data Formatting
Time Management
OS / μC
ADC
SD Card
John Dmitriy Michael Adam Troy
Time I/O
SD
John Dmitriy Michael Adam Troy
Task
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
John Dmitriy Michael Adam Troy
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

NOAA
 Providing optical parts (mirrors, mounts,
laser controller, optical breadboard, laser)
 Will keep the prototype upon completion

UROP Funding (Pending)
 Up to $1000 funding
 Requires a report upon completion
John Dmitriy Michael Adam Troy
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Not able to integrate OS with Optics
 Will demonstrate the systems separately at
Expo

Not able to construct casing for a
portable device
 Demonstrate the project on separate
breadboards at Expo
John Dmitriy Michael Adam Troy
Bob
Carissa
Tom
Alex
Sam
Image obtained from: http://www.picgifs.com/graphics/noahs-ark/
John Dmitriy Michael Adam Troy