Sponsor: NXP Semiconductor Mentors: Dr. Jacob Murray, Scott Odle

Fluorescence Sensor
Sponsor:
NXP
Semiconductor
NORTH PUGET SOUND AT EVERETT
Mentors: Dr. Jacob Murray, Scott Odle, & Ken Doe
Luke Vybiral, Lauren Laskarris, Jeremy Canaria, Grant Austin, & Michael Sahlbom
Background
Catalina Sea Ranch, LLC (CSR) is the developer of
the first offshore shellfish aquaculture facility in
federally regulated waters of the U.S. CSR would
like to integrate a low cost fluorescence sensor into
their aquaculture monitoring network to ensure
adequate mussel food supply. NXP Semiconductor
tasked us to design an economical sensor. This
sensor would be installed in an array of sensors and
quantify phytoplankton biomass throughout the
mussel farm.
Objectives
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Low cost
Withstand a corrosive marine environment
100ft water pressure vessel
Open source hardware and software
Component/Housing Modularity
Integration to CSR’s IoT system
Easy maintenance
Impact Analysis
Economic: Plankton biomass is often estimated with
time-consuming in vitro tests. Portable
fluorometers currently available are expensive.
A low-cost, reliable in situ fluorometer would be
marketable to many industries.
Global Impact: This sensor is to be part of a network
TM
integrated into an IoT. Marine Big Data will
provide real-time ocean data for research.
Environmental: The ocean is the primary regulator of
the atmosphere, accounting for ~70% of the
earths oxygen. This sensor can provide a metric
for the current health of the earths oceans.
There is also a large need to monitor waters
algal blooms, especially in lakes, rivers, and
near-shore environments where agricultural or
industrial runoff may occur.
System Description
Circuit Schematic & Sensor Arrangement
Power supply and wireless
external comm system exist
at the hub. Hub
microprocessor sends
power to the sensors &
receives digital signals at
hourly intervals. The sensor
consists of a blue, narrow
beam LED, a photodiode
with light filter, a
transimpedance amplifier
and a microprocessor.
Components are oriented so
the LED excites fluorescence
in chlorophyll within the view
angle of the photodiode,
producing a current
proportional to chlorophyll
concentration (and
phytoplankton biomass). The
amplifier converts the
current to a measurable
voltage. The processor
converts the voltage to a
digital signal and transmits
back to the hub.
Future Plan
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Phytoplankton Environment
Precise calculation of biomass
from Chlorophyll a is complex:
• Carbon: Chl a ratio depends
upon species and life-cycle
• Plankton vary in size greatly
• Turbidity, acidity, temperature
are confounding factors
Glossary
Tetraselmis
12 microns
Thalassiora Weissflogii
6-20 microns
Data
Conditions
Test Data
BioChemical
Marine Water
Fresh Water
PH Range
Turbidity
Temperature
etc
CSR: Catalina Sea Ranch
In Situ: On site testing
In Vitro: Laboratory Testing
IoT: Internet of Things
Spectrophotometry:
Measurement of light through
a medium
NOAA: National Oceanic and
Atmospheric Administration
Acknowledgements
Dual Rail (±5V) Differential Amplifier w/ 1 GΩ - 1 GΩ - 1 nF
Environment
Matching sensor size to its application
Implementation of CANBUS communication
Integrating wireless communication between buoys
Solar power
Printed Circuit Board
More on site testing
Ambient Light
Condition
Organism(s)
(Type, Size,
Viability)
Intensity
Wavelength
Direction
etc
Diatom
Cyanobacteria
Dinoflagellate
Seaweed
Various
etc
Biomass
Density
Chlorophyll +
Pheophytin
Density
0.1 mg/L – 1.0
0.1 – 200.0 µg/L
g/L
Electrical
Fluorescent
Light Power
Total
System
Power
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440nm
LED
Power
25 nW –
1 mW
9W
.15 W
PD Current
Amplifier
Reference
Volts
Amplifier
Volts
OverVolts
0.01-300 µA
0V
0-3 V
0-3 V
We would like to give a special thanks to:
Our Sponsor, NXP Semiconductor; Reg Olsen of Catalina
Sea Ranch; Pete Kasselman & Roger Hicks of EvCC;
Spectra Laboratories ; Dr. Eric Henry of Reed Mariculture;
and Dr. Jacob Murray of WSU.
Gallant