Thomas G. Wolcott, Alex Dean,
Mihail Sichitiu
NCSU - MEAS and ECE
Participants
• North Carolina State University
– Alex Dean, Mihail Sichitiu - Electrical and Computer Engineering
– Thomas G. Wolcott - Marine, Earth and Atmospheric Sciences (Emeritus)
• Chesapeake Bay Environmental Center (CBEC)
– Vicki Paulas, Judy Wink
– Mission: Promote
stewardship and
sustainability through
environmental education
and habitat restoration.
– Four artificial reefs for
oyster bars and fish habitat.
• South-Eastern Coastal
Ocean Observing
Regional Association
(SECOORA)
Goals for the “CEMS” System
•
•
•
•
Networked—data to web in real time
Reliable—data secure
Versatile—wide variety of sensors
Citizen/Student-friendly—public
“ownership”
• Economical—permits dense arrays, high
resolution
“Lab” Test Site
Field Test Sites
Smithsonian
Environmental
Research Center
(SERC)
Chesapeake
Bay
Environmental
Center (CBEC)
Sample Data: Depth
Temperature
Temperature and Salinity
Noon
Sep 16
Midnight
Sep 17
Noon
Transmissivity
Noon
Sep 16
Midnight
Sep 17
Noon
Oyster Gapes (2 individuals)
Noon
Sep 16
Midnight
Sep 17
Noon
Oyster Gapes (all)
Noon
Sep 16
Midnight
Sep 17
Noon
Battery and Solar Panel Voltages
CEMS Approach
Web Server
Internet
SECOORA
Web Server
Comm. Link
Module
(Linux SBC
on piling or buoy)
Datalogger
module
Instrumented Oysters & Environmental Sensors
3G Cell
Network
Smartphone/Tablet
for Opportunistic
Data Collection,
Display and Relay
Image courtesy NOAA
Sensors
“ABLE” brain
controls, reads…
Salinity & Temperature
Depth/Pressure
Oyster Gape
Transmissivity
Price for CEMS Node
Server, access point, cable modem:
Comm Link Module, wi-fi card, antenna:
Power supply (PV/controller, battery, V-regs):
Datalogger module:
Sensors
Depth $30
Temp: 2 @ $3
Salinity, mostly machining, 2
Transmissivity (mostly machining,) 2
Oyster gapes: 16 @ $3/oyster
$600
$200
$335
$100
$200
$ 6
$ 20
$100
$ 50
Plus incidentals: PVC frame, cables, housings…
Total (one logger module, one comm. module)
~$1500
What Next?
• Standardize sensor-datalogger protocols too
• Sensor refinement and development
– Easy variables: waves, currents
– Hard variables: DO, pH, nutrients…
• [Nearly] Real-time data downloading and viewing
– On SECOORA website
– on students’/visitors smart phones or Android tablets
• A mobile datalogging module that can be towed by small
boat, and log appropriate additional variables en route:
– Light (PAR)
– GPS position
– Boat’s compass heading
There will be a slight delay…
Thank you!
• Funding: NSF
• PIs:
– tom_wolcott@ncsu.edu
– alex_dean@ncsu.edu
– mihail_sichitiu@ncsu.edu
• NCSU CEMS development log:
https://sites.google.com/site/ncsucems/
• More about CBEC: http://www.bayrestoration.org
Temperature, Conductivity (Salinity)
• Each datalogger controls two, comprising:
– A conductivity cell with graphite electrodes in a PVC block.
Readings are reproducible to 0.01 psu in the laboratory.
– A temperature sensor IC, whose signal is conditioned by a multi-range amplifier and
digitized by the micro-controller.
Readings are reproducible to 0.01C after 3-temperature 2nd-order calibration.
Pressure Sensor
• A MEMS differential pressure sensor is mounted on the ABLE
board, communicating with the outside of the pressure housing via
an oil-filled polyurethane tube. For shallow estuaries, a unit with a
one-atmosphere span (resolution < 1 cm) is used with a oneatmosphere reference.
Oyster Gape Sensors
• Oyster gape is to be measured as
an indication of feeding activity
and health.
• Hall sensors are affixed to one
valve of the oysters, and a rareearth magnet to the other.
• The datalogger module accepts
behavioral data from 16 oysters.
Transmissometers
• Datalogging unit controls two
modules.
• A white LED illuminates a light
sensor sensitive to four color bands,
with a 10 cm light path.
• “Eyelids” (wipers) prevent biofouling of the LED and sensor.
• The transmissivity in water for each
color band is expressed as %
transmissivity in clear water.