ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 1 Arduino Based Oceanographic Instruments

47 Pages·2015·0.55 MB·English

Running Head: ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 1

Arduino Based Oceanographic Instruments:
An Implementation Strategy for Low-Cost Sensors
Daniel P. Langis
California State Maritime Academy
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Abstract
Oceanographic instruments are expensive, yet essential tools for conducting research on critical
environmental processes. Modern trends in technological advancement and inexpensive
electronics would suggest that oceanographic instruments should be becoming cheaper; however,
low-cost instruments are not yet a reality. This paper describes an implementation strategy and
justification for a new form of low-cost instruments using Arduino-based microcontrollers. It
describes present-day instruments and methods, the need for low-cost sensors, and barriers which
have thus far prevented low-cost instruments from being realized. It also details the unique
advantages of the Arduino platform which make it an ideal candidate for reducing costs and
suggests how to capitalize on its open source design and flexibility. Particular attention is paid
to providing a holistic approach towards reducing life-cycle costs at all stages of planning,
development, and operation. This strategy may be used as a baseline and unifying vision for any
oceanographic research institution(s) wishing to develop low-cost instruments and reap the
benefits of expanding research opportunities.
Keywords: Oceanography, instruments, sensors, low-cost, Arduino, life-cycle cost
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Arduino Based Oceanographic Instruments:
An Implementation Strategy for Low-Cost Sensors
The oceans and their resources are major determinants of the global climate, state of the
environment, and economic productivity of nations across the globe – a 2012 study estimated
that if human impacts on the ocean continue unabated, declines in ocean health and
services will cost the global economy $428 billion per year by 2050, and $1.979 trillion
per year by 2100. Alternatively, steps to reduce these impacts could save more than a
trillion dollars per year by 2100, reducing the cost of human impacts to $612 billion
(Virginia Institute of Marine Science).
Oceanographic studies are necessary to understand the scope and nature of potential
impacts. Those studies are heavily reliant on the measurement and collection of data from a
variety of sensors and observation platforms. Characteristics such as water temperature, salinity,
depth, currents, fluorescence, photosynthetic radiation, and pH are all used to monitor and
predict the health and productivity of the oceans.
One of the major cruxes in oceanography is how to collect accurate measurements and
sample water from extremely remote, hostile environments. “The ocean is the most complex,
challenging, and harsh environment on Earth and accessing it requires specially designed tools
and technology” (NOAA, 2013). Traditional methods have relied on robust, precise instruments
which are often deployed on elaborate mooring systems from a research vessel – a prospect
which is both expensive and dangerous. Recent advances in technology, such as satellite
observations and remotely operated vehicles, have already proven great alternatives to traditional
methods for many applications (National Ocean Council, 2011), but many programs are still
dependent on bulky and expensive instrumentation for the backbone of their data collection.
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Due to the dramatic reduction in size and cost of electronic components, there is great
hope on the horizon for redefining how instruments are produced and utilized in the field. To
many, it seems that the industry is on the cusp of a revolution which could decrease costs of
collecting certain data by orders of magnitude. With the remarkable developments and products
made in land-based electronics such as cell phones and computers, one might expect the
revolution to be at hand. There is hope that a miraculous solution will appear which will provide
an immediate low-cost solution to the myriad challenges of technological innovation and
collecting data in ocean environments. An ideal solution would integrate a suite of highly
accurate sensors into a miniaturized package and be available at very low cost.
Despite the optimistic perspective, a survey of the actual available products would
suggest that very few ultra-low-cost solutions have actually been developed. A host of reasons
exist for the stagnation in what could be a potentially ground-breaking arena for innovation. A
number of the major obstacles preventing ultra-low-cost oceanographic instruments from being
produced are listed below. This list is neither exhaustive nor absolute, but is provided to
illuminate a few of the central challenges that this document and implementation strategy are
intended to address and overcome.
1. Many individuals have made attempts at portions of ultra-low-cost sensor
development (such as conducting studies on individual low-cost sensors) but little
work has been done to propose an end-to-end solution that would make them a
reality. A complete solution must consider how to integrate complex issues such as
product development, data quality, testing, calibration, maintenance, and user
interaction – all while driving down total cost (Blanchard, 2008, p.10).
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2. The instrumentation industry is dominated by a limited number of commercial
companies who have a strong hold on the market. Those companies create first-rate
products and do provide reliable end-to-end solutions for the issues above. Although
expensive, the costs for oceanographic instruments are incorporated into budgets as
the price of conducting research; programs also have large amounts of capital already
invested in instruments. These factors reduce pressure and create a justifiable
reluctance to develop and adopt new technologies.
3. Organizational processes and traditions are very hard to change. The adoption of any
revolutionary practice may redefine processes, alter job responsibilities, and create
internal disruptions which require significant organizational change. The
development of ultra-low-cost sensors must also consider how the technology will be
utilized and provide time and recommendations for adopting new processes.
The implementation strategy that follows justifies using ‘Arduino’ based electronics as
the foundation for low-cost instrumentation. The Arduino is an open-source electronics
platform, intended for making interactive projects (Arduino, n.d.). Although inexpensive and
modest in appearance, it is substantively capable of driving the functions of complex
oceanographic instruments. Additionally, the opportunities resulting from open-source design,
modularity, customization, and cost reduction would make it ideal for the challenges faced in
oceanography. Significant discussion is given to exactly how and why the foundation for this
platform should be established, what types of applications it is best suited for, and how to
approach future product development.
Oceanographic research institutions such as the National Oceanic and Atmospheric
Administration, Woods Hole Oceanographic Institute, and the Scripps Institute of Oceanography
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are likely to be the immediate beneficiaries of this implementation strategy. It can provide a
unifying vision and direction for the development of a branch of technology which can be shared
across institutions. Individual laboratories and programs within those institutions would then be
able to adapt and customize these technologies for specific projects.
The creation of ultra-low-cost sensors has the opportunity to provide a dramatic impact
on the environment, commercial industries, and the economy as a whole. Reducing instrument
costs by some order of magnitude has the potential to improve monitoring of the climate,
generate new models, improve forecasting, and enhance our ability to responsibly manage our
planet’s resources.
Literature Review
Present-Day Platforms and Methods
In order to understand how low-cost instruments may be developed and applied in
oceanography, one must first consider the current methods of data acquisition and the
fundamental strengths and weaknesses of the various approaches. The National Academy of
Science’s Committee on an Ocean Infrastructure Strategy published a document in addressing
the Critical Infrastructure for Ocean Research and Societal Needs in 2030. The document posed
major research questions, addressed technology trends, and set broad strategic goals for how
technology and infrastructure will be applied specifically to oceanography in the next two
decades (2011). A number of these trends are summarized below.
Ships. Traditional oceanography relied on research vessels equipped with sophisticated
instrumentation to conduct in-situ measurements or sampling and deploy mooring systems to
monitor remote environments. Ships have distinct advantages as mobile, adaptable platforms,
but are remarkably expensive. According to the National Ocean Council’s Federal
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Oceanographic Fleet Status Report (2013, p. 20), “Federal agencies are facing numerous
challenges associated with cost-effectively operating and maintaining the Fleet” of
oceanographic vessels. Fuel costs have increased some 400% since 2003, aging vessels require
higher maintenance costs, personnel costs for salaries and training are increasing, and new safety
and environmental standards are becoming more stringent (National Ocean Council, 2013, pp.
19-20). The overall result is that ship utilization rates are decreasing and researchers are looking
to alternative methods and examining how to reduce other costs in order to afford ship-time.
Total fleet operating costs have risen dramatically in the past several years and were well over
$200 million annually from 2008 to 2012 – forcing total operating days to fall from nearly 8500
to around 7000 in that same time (National Ocean Council, 2013, pp. 21).
Moorings. Moored buoy systems have been another staple of oceanography since the
1960s. Conventionally, moorings are equipped with precision calibrated instruments and
provide important ground-truth and multi-decadal time series data. As they provide such
important benchmarks, mooring systems “will remain a key element of ocean observing
infrastructure by providing high-frequency fixed location data” (National Academy of Science,
2011, p. 30). However, an individual mooring may require many tens of thousands of dollars in
instrumentation and nearly all require the expensive services of vessels to maintain. Their bulk
and complexity can also make them labor intensive and dangerous to deploy and recover.
Autonomous and Remote Vehicles. In recent years, advances in autonomous systems,
such as AUVs, gliders, and ARGO profiling floats have provided an avenue for broad spatial
remote sensing systems. These systems have been developed in response to rising costs and
safety concerns, and have been enabled by advancements in modern technology.
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Indeed, at the onset of the twenty-first century a global program (Argo…) to continuously
monitor velocity within the water column was initiated using relatively inexpensive
subsurface floats that follow the subsurface currents (mostly at a single depth) and report
back to satellites at regular intervals. This program has already revolutionized observing
of the ocean interior, primarily because of the temperature and salinity profiles collected
on every trip to the surface, which has been standardized at ten-day intervals; the velocity
data have been less utilized. A global deployment of surface drifters accomplishes the
same objective at the sea surface…These ocean-wide Lagrangian sampling methods were
not possible prior to the beginning of global satellite communications… (Talley, Pickard,
Emery, and Swift, 2011, Ch. 16, p. 2)
Autonomous systems have vastly increased global measurements in the ocean and
reduced the need for some ship-based measurements. These systems have provided some
reprieve from ship costs, but can still be expensive platforms. They do require substantial
financial and program investment and are best suited for deep-ocean, open-ocean, long-term
deployments – not necessarily for coastal or spatially precise missions. As far as cost for the
ARGO program,
Each float costs about $15,000 USD and this cost about doubles when the cost of
handling the data and running the project is taken into account. Thus the approximate
cost of the project is 800 x $30,000 = $24 [million] per year. (Argo FAQ. n.d.)
Furthermore, future modifications to ARGO floats which could add instrumentation such
as biological and chemical sensors or Iridium communications are likely to increase costs by
several thousands of dollars for each upgrade.
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Other Innovations such as Liquid Robotics’ Wave Glider have added controllable,
remotely operated vehicles to the available options. In terms of total cost, they are a much more
economical option than research vessels for obtaining remote measurements. However, the
newest generation of Wave Glider (SV3) will cost approximately $300,000, significantly more
than the previous $175,000 version (SV2) (Venture Beat, 2013).
The National Ocean Council made this summary about the above technologies:
In the past two decades, use of floats, gliders, ROVS, AUVS, and scientific seafloor
cables has increased; use of ships, drifters, moorings, and towed arrays have remained
stable; and use of HOVs has declined. Based on these trends, utilization and capabilities
for floats, gliders, ROVs, AUVs, ships, and moorings will continue to increase for the
next 20 years, and HOV use is likely to remain stable. Ships will continue to be an
essential component of ocean research infrastructure; however, the increasing use of
autonomous and unmanned assets may change how ships are used. (2011, p. 31)
Satellite Imagery. Satellites, communications technology, and vast amounts of
bandwidth have opened the door to some new options for sensing such as satellite imagery and
moored cable systems. Satellite imagery can provide information on parameters like wind,
temperature, ice distribution, and phytoplankton concentration. Satellites are, of course, limited
to the type of data they can collect viewing the ocean surface and require significant investment
to build and maintain.
Cabled Observatories. Permanently cabled ocean observatory systems may replace
some traditional mooring systems at a substantially reduced life-cycle cost according to Chave,
Waterworth, Maffei, and Massion (2004). Linked to shore by fiber optic cables, they would be
able to transmit near instantaneous measurements from fixed locations to shore, whereas
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traditional moorings may take over a year to collect, recover, and process data. While cabled
systems may provide a better alternative than traditional moorings for some locations, they will
nonetheless suffer from some of the same drawbacks as traditional moorings – namely,
significant infrastructure investment and planning, expensive instrumentation, and high
maintenance costs.
Efforts toward Low-Cost Instrumentation
Background. The National Ocean Council's document describes how oceanographic
sensors are needed to measure physical, biological and chemical, and geological/geophysical
processes. Two of its principal recommendations to the nation were to “expand abilities for
autonomous monitoring at a wide range of spatial and temporal scales with greater sensor and
platform capabilities” and “support continued innovation in ocean infrastructure development.
Of particular note is the need to develop in situ sensors, especially biogeochemical sensors”
(2011, p.3).
For many years, researchers have purported the need for less expensive instrumentation
to obtain a greater number of discrete measurements. The spatial resolution of data, as well as
models used for prediction, both depend on the frequency and location of sampling. In order to
increase the spatial resolution of data and models, especially in heterogeneous environments, a
large number of measurements must be acquired. One of the best ways to resolve this issue is to
create a large network of (hopefully) inexpensive instruments. The need for inexpensive
instruments has been well known for many years. According to Erikson (1997), “Progress in
meeting the daunting challenge of sampling ocean variability will be made through development
of small cheap autonomous instruments that can be used in large numbers.”