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

ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 2

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. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 4

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). ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 5

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 ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 6 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 ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 7

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. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 8

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. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 9

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 ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 10 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.” ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 11

Recent technological advancements have opened the door to the possibility of such instruments. For example,

Circa 1990, there were only a few 8-bit microprocessor systems with sufficiently low

power consumption for autonomous deployments, and they had volatile solid-state

memory and limited computational power and data storage. In 2010, processors with

orders-of-magnitude-higher computational power can navigate systems, command

sensors and actuators, adapt missions, and retain gigabytes of data in robust solid-state

memory. There have been parallel improvements in power availability, including the

transition from alkaline to lithium batteries. (National Ocean Council, 2011, pp. 28-29)

Examples. Many attempts and proposals have been made in recent years to produce concepts for low-cost oceanographic instruments though few have gained significant traction or seen widespread use. More extensive discussion of why they have not, in spite of opportunities, is provided in the section on Technological and Organizational Challenges. A number of examples of low-cost instrument designs are provided below. In many cases, these projects present designs which cost at least an order of magnitude less than traditional commercial instruments.

The mainstay of oceanographic studies are what are known as CTD profiles

(Conductivity, Temperature and Depth). These are the “primary tool for determining essential physical properties of sea water. [They] give scientists a precise and comprehensive charting of the distribution and variation of water temperature, salinity, and density that helps to understand how the oceans affect life” (Woods Hole Oceanographic Institute, 2007). In 2013, an attempt was initiated to make an “OpenCTD” – a low-cost, open-source CTD, which could be constructed for less than $200. When compared to the cost of commercial equipment, this is ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 12 incredibly inexpensive. “Commercial CTD’s start at more the $5,000 and can climb as high as

$25,000 or more” (Thaler, Sturdivant, 2013). Unfortunately, the first prototype of OpenCTD was created with the basic components installed, but appears not to have completed the process of testing and calibration according to the team’s crowd-funding site.

A novel design, mimicking the ARGO profiling floats was completed in 2011 (Paradis,

2011). The ‘ECS Unit’ was constructed which was functionally capable of conducting multiple autonomous profiles using internal buoyancy control. Despite the complex operational profile, the device cost only about $1,500 to make. The unit was not as sophisticated, accurate, or long- lasting as ARGO floats, but nonetheless presented an economical option which could conduct multiple CTD profiles and still be cost-effective enough to be expendable.

A number of other studies have been conducted to develop sensors for measuring individual parameters.

A 2013 study by Leeuw, Boss, and Wright demonstrated that a fluorometer capable of measuring chlorophyll  using blue LED excitation could be constructed for $150 with little to no previous experience. Commercial fluorometers start at roughly $1,750, not including the interface to continuously log data. Complete units can cost $3,000-$5,000 or more (Turner

Designs, n.d).

Another study demonstrated that current velocity profiles could be measured at a “spatial and temporal scale relevant to the ecology of individual benthos and fish” using a device constructed for less than $150 (Johansen, 2014, p. 1).

A plethora of current sensors is currently being used by oceanographers worldwide

including Electromagnetic Current Meters and Acoustic Doppler Current Profilers

(ADCP) [11]. These instruments allow long term monitoring for months to years and ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 13

some are capable of high resolution profiling of the entire water column around each

instrument including near bottom velocity measures [12]–[14]. However, instruments

such as the ADCP's are very expensive ($10,000–25,000 per instrument) and in most

cases not economically viable for profiling currents in multiple locations simultaneously.

(Johansen, 2014, p. 2)

“As ocean and estuarine acidification has gained attention from scientists and policy makers over the last several years, the need to develop cost-effective and accurate methods to monitor the chemistry of our coasts and oceans has become increasingly important” (Yang,

Patsavas, Byrne, and Ma, 2014). An LED photometer was developed which was accurate for measuring pH to .01 units of the state-of-the-art spectrophotometric measurements. However, the parts for the sensor developed in this study cost only about $50, whereas the state-of-the-art model cost about $6,000 (Yang, Patsavas, Byrne, and Ma, 2014).

Similar projects have been completed for measuring parameters such as turbidity (Kelley et. al., 2014) and Chemical Oxygen Demand (Anzalone, Glover, and Pearce, 2013), each using instruments which cost $50-100. In this case, the turbidity sensor would cost approximately only

4% of the cost of a commercial instrument (Kelley et. al., 2014).

Technological and Organizational Challenges

Despite the recent progress, none of the above examples have been adopted on a large scale or seem to be gaining much traction. One must ask and consider why. One might suggest that low-cost instrumentation is still in the early design phases and needs more time to evolve.

However, this does not answer the question, but merely suggests that it still needs to be answered. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 14

The primary underlying reason is that the difficulty in implementing low-cost sensors is a much more comprehensive problem. In Marty Cagan’s book, “Inspired: How to Create Products

Customers Love”, he stresses that products must solve and address a real problem. In oceanography, the problem researchers must solve asks how to design, evaluate, test, calibrate, deploy, recover, and maintain instruments. A successful low-cost instrument must consider not only if building a certain type of sensor is possible, but also how designers and users will interact with it throughout its life-cycle.

Low-cost, open-source designs are novel and appealing but also present serious challenges. Many designs (especially in their incipient forms) are labor intensive and require a great deal of time and attention to build, test, and maintain. Commercial instruments, on the other hand, are sold as fully constructed, calibrated, reliable instruments. If the equipment malfunctions or needs to be re-calibrated, it is usually sent back to the manufacturer who then performs the maintenance. These are important procedures which must be factored into the value of instruments, as researchers pay for far more than just the cost of materials when purchasing commercial products and can just as easily neglect downstream costs. According to

Blanchard (2008),

In general, experience indicated that the life-cycle costs of many of the systems in use

today are increasing. Although a great deal of emphasis has been placed on minimizing

the costs associated with the procurement and acquisition of systems, little attention has

been paid to the costs of system operation and support. In the design of systems, it is

important to view all decisions in the context of total cost if one is to properly assess the

risks associated with the decision in question. (p. 10)

And ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 15

It has been determined that a major portion of the projected life-cycle cost for a given

system stems from the consequences of decisions made during the early stages of

advance planning and system conceptual design. Such decisions, which can have a

significant impact on downstream costs, relate to the definition of operational

requirements…, maintenance and support policies…, allocations associated with manual

versus automation applications…, hardware versus software applications, the selection of

materials, the selection of a manufacturing process, whether a COTS item should be

selected versus the pursuit of a new design approach and so on. (p. 13)

Researchers must consider total life-cycle costs when developing low-cost instruments in order for them to truly be low-cost. Unique procedures may need to be developed for test, calibration, and maintenance of instruments to drive down total costs. An implementation strategy is also critical to the future success of low-cost instrumentation because of the effect it will have on downstream costs.

Additionally, significant care must be given to ensure data integrity and standardization of instruments. Significant attention has been given to standardizing communications and data storage protocols across instruments in new programs such as permanent oceanographic observatories (Maffei et. al., n.d.). Open-source designs present the opportunity to customize and easily modify projects for individual users, but this can also lead to easily and inadvertently altering established standards.

The single most difficult concern with low-cost instrumentation revolves around the reliability of data. A great deal of life and property can often depend on oceanographic measurements. As NOAA’s Ocean System Test and Evaluation Plan described, sensors need to be evaluated, quality control procedures developed, and all must be assured by traceable ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 16 calibrations and redundant sensors in order to ensure they are introduced in a responsible manner

(National Ocean Service, 2001). As in the case of the NOS, OSTEP was tasked with “providing data quality assurance to a level required for NOS to accept legal liability for observations and derived navigation safety products and services” (National Ocean Service, 2001, p. 2). Low-cost instruments may still be substantially accurate for a broad variety of studies; nonetheless, they must be used judiciously and in the appropriate applications, based on their inherent uncertainty and error.

Basics of the Arduino Platform

The National Ocean Council stated that in coming years, “consumer-driven advances in microelectronics are likely to continue to benefit the ocean research community through increased platform capabilities. This will be enabled by modular platforms that can easily accommodate rapidly evolving sensors” (2011, p. 29).

The Arduino offers exactly such a platform at the most basic level. Its design enables it to be an ideal platform for both development and implementation of new instrumentation. The

Arduino is an open-source electronics platform, intended for anyone making interactive projects

(Arduino, n.d.) (Oceanographic projects are no exception.) It integrates a micro-controller, programming language, and development environment to create easily programmable inputs and outputs in a convenient package. A variety of Arduino products are available, some in miniature packages, with typical models starting around $25 each (Adafruit, n.d.). Since the Arduino and programming language are all open-source, plans and sample projects are widely available.

Since it can interface quickly and easily with COST components, such as integrated circuits and

‘shields’, it offers distinct advantages that would allow modular design and enable laboratories to build customized instruments. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 17

The essential feature of the Arduino is that its user-friendly platform reduces the previously intricate electrical and computer engineering task of sensor design to a much simpler process of evaluating performance. The fact that a number of the above examples of low cost sensors use Arduinos as a foundation for the project is no coincidence, as it offers unique advantages for reducing time, cost, and complexity in the design process (Thaler, Sturdivant,

2013), (Leeuw, Boss, and Wright, 2013), (Yang, Patsavas, Byrne, and Ma, 2014), (Kelley et. al.,

2014) and (Johansen, 2014).

Additional products already exist which can be easily added to the Arduino to enhance the capability of these low-cost instruments. For example, GPS, wireless communications, and data logging circuits and are readily available for only $20-30 each (Adafruit, n.d) as is straightforward code to make each effective. Even more elaborate devices, such as the

RockBlock, developed by Rock Seven (n.d.), allow plug and play satellite communication providing global 2-way communication to Arduino devices. The RockBlock only costs around

$250, plus small data charges.

Considering the above examples and available technology, it may be quite possible to build individual instruments at incredibly low costs of around $75-$150. Furthermore, it may be possible to integrate a suite of physical, biological, and chemical sensors into a single instrument for $1,000-$2,000 - about the same as a modern commercial instrument with a single sensor.

Low-cost instrumentation has the potential to dramatically reduce costs and open the door for new entirely new areas of research in oceanography.

ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 18

An Implementation Strategy Major Objectives

The implementation strategy described here seeks to fulfill several major objectives. It strives to:

1. Describe the importance of low-cost instrumentation and discuss the need to develop a

comprehensive plan for making those products a reality. An end-to-end solution must

consider costs and operational requirements at all stages of product life-cycle in order to

be successful.

2. Discuss the major advantages and limitations of the Arduino platform and present the

implications for specific oceanographic research endeavors.

3. Make technical recommendations for a standard architecture, which will transform the

Arduino from a general electronics platform to one specifically suited for oceanographic

instruments.

4. Make strategic and procedural recommendations for integrating instruments into

oceanographic research institutions and projects.

Highlights of the Arduino Platform

Advantages. The Arduino platform is highly advantageous and offers unique opportunities for a host of reasons. Most obvious among these is its incredibly low cost. Basic

Arduino modules, such as the Uno R3, are available for ~$25 (Adafruit, n.d.). A wide variety of

Arduino boards and configurations exist, each with slightly different technical specifications and sizes. Throughout this discussion, the Arduino Uno is used as a baseline comparison because of its popularity, low cost, and middle-of-the-road components

ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 19

Despite its low cost, the Arduino is a highly versatile platform which can be used to interface with almost any type of modern integrated circuit, such as Analog-to-Digital

Converters, memory cards, real-time clocks, or power switching devices. As for oceanographic research, it is equally feasible to connect a full suite of oceanographic sensors to a single

Arduino controller. If individual low-cost sensors for oceanographic measurements can be developed, the Arduino is an ideal platform for integrating multiple sensors into successful low- cost instruments.

Figure 1: Photo of Arduino Uno R3 (Arduino, n.d.)

The Arduino Uno has 20 pins which can be configured as input or outputs for signal transmission or data communication (Arduino, n.d.). Depending on the application, users can add sensors and circuit components to each of the pins, without affecting the base design. This type of modular design is especially beneficial for oceanographic research applications.

Different laboratories and research teams using Arduino-based instruments could add individual sensors for according to their specific needs while reducing total costs by connecting them to a single processing unit. Similarly, modular designs can significantly reduce repair costs if ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 20 instruments are designed with interchangeable parts. Interchangeable parts allow a single component such as a sensor or accompanying integrated circuit to be replaced, rather than the entire unit – something that is not possible with traditional embedded systems.

Along with a flexible hardware interface, Arduinos have a flexible software interface and can be easily programmed with customized code. Researchers using these platforms could easily modify sampling intervals and data output, or even program instruments to perform different functions based on environmental conditions. For example, an instrument could sample rapidly or even deploy secondary devices when the local ecosystem is especially active, but sample more slowly and conserve energy during times when the ecosystem is relatively dormant. Flexible programs would allow for more unique research opportunities and investigating previously unapproachable hypotheses. If a device could wait for a large plankton bloom or high ambient light conditions before collecting large amounts of data or releasing itself from the ocean bottom, researchers may be able to better characterize highly transient conditions and better identify productivity levels which could previously only be measured during occasional opportunistic circumstances. Allowing users to customize data output would also simplify data ingestion and processing after instruments are recovered.

Low-cost micro-controllers have been available for some time (National Ocean Council,

2013, pp. 28-29), but the Arduino is truly unique. It reduces what used to be complex computer and electrical engineering endeavors into projects that can be completed by designers who have minimal experience in electronics or programming. Its popularity has made it nearly ubiquitous in the “Maker” culture, and pre-written libraries of code and examples are available for a wide variety of integrated circuits and applications. This has a compounding effect and again dramatically reduces the difficulty in designing projects using the Arduino – allowing for even ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 21 novice designers to engage in rapid prototype development. In any case, reducing time and cost involved in the design process leads to a reduction in total life cycle costs. When developing new instruments, these savings can be significant and should be considered in addition to the savings from material costs.

Since the code, schematics, and circuit board designs for Arduino boards are all open source, organizations and universities around the globe can engage in collaborative development.

Many oceanographic research institutions lack centralized, dedicated engineering teams such as those in companies specializing in producing traditional oceanographic instruments. Those that do have engineering teams are stretched quite thin, often as a result of supporting multiple research groups. As a result, as evidenced by many examples provided in the Literature Review, non-engineering students and professionals across organizations engage in the creative design process and are highly invested in developing innovative, low-cost solutions for instrumentation.

If oceanographic institutions across the globe can adopt a common architecture such as the

Arduino platform, they can also share in their progress and build on each other’s work much more easily. Again, the Arduino platform is particularly attractive because of its low cost and minimal electronics experience required to operate. Since it is so widely available, almost anyone can engage in the processes needed for creating successful instruments, whether it is conceptual design, full-scale production, testing, calibration, or quality control. Distributing development across organizations would also serve to reduce the costs incurred by any one group. Global collaborative development also highlights the need for sharing and distributing information – a topic discussed further below.

Table 1 below provides a summary of the advantages discussed above and their implications for oceanographic research. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 22

Table 1: Advantages of Arduino Platform for Oceanographic Instruments

Advantage of Arduino Platform Positive Influence for Oceanographic

Applications

-Inexpensive (~$25) -Reduces baseline cost of designing, testing,

and building instruments.

-Very popular development tool -Many students and researchers already

familiar with Arduinos.

-Libraries and examples are widely available.

-Modular Design -Projects can be designed with

interchangeable parts.

-Teams can build custom projects for specific

research needs.

-Open source design -Organizations and universities can engage in

collaborative development of instruments and

sensors.

-Easily programmable -Data output and program structures can be

customized for individual projects.

-Flexible platform -Can interface with a wide variety of

integrated circuits or sensors for more

complex projects.

-Can support full suite of oceanographic

sensors with a single controller. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 23

Disadvantages. Despite the numerous advantages, the Arduino platform does possess some inherent limitations. Some might suggest that these render the Arduino unsuitable for oceanographic research, but all can be overcome by adopting a standard architecture and judiciously selecting research endeavors for Arduino based instruments. Both approaches will be discussed at length in subsequent sections. .

To begin, Arduinos are generally not optimized for minimal power consumption.

Standard boards draw ~50 mA when running, even without additional circuitry or sensors. If running continuously for a 1-year remote deployment, such a device would require 438 Amp- hours of battery power, or approximately 365 standard 9V lithium batteries. Modifications must be made to improve power consumption and avoid deployments requiring continuous operation.

By including basic circuitry that allows instruments to power-down and wake-up at predetermined intervals, this problem can largely be eliminated. For example, an instrument that only needs to be “awake” for one second to take a measurement every 10 minutes can easily operate for a full year on a single standard 9V battery.

Arduino boards also have limited built-in circuitry. The Uno does not have memory storage capability (such as an SD card reader) or a real time clock. The built in Analog-to-

Digital converter (ADC) is also limited to a resolution of only 10 bits. The 10-bit ADC limits analog measurements to only 1024 possible voltage readings, severely limiting the resolution of possible measurements. For example, a sensor measuring temperature would at best be limited to about +/- 0.1° accuracy between 32°F and 130°F. While adequate for some applications, these standards are nowhere near sufficient for oceanographic research and not competitive with current products. By comparison, SeaBird Electronics’ SBE56 has an accuracy of +/- 0.0036°F and can sample approximately four times per minute, for 2 years, on a single battery (Seabird ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 24

Electronics, n.d.). Even though Arduino boards do not typically have sophisticated components built-in, they can easily interface with other integrated circuits – thus converting them into capable platforms for data collection and research. Adding components for oceanographic instruments can be simplified considerably by combining all essential components into a single

‘shield’- a process described in depth later.

Boards such as the Arduino Uno have limited capacity for flash memory (32kB) and static random access memory (1 kB) which does pose some limitation on program length and complexity (Arduino, n.d.). However, this space is adequate for most applications and thorough testing, documentation, and training can prevent instruments from malfunctioning in field deployments. Additionally, other Arduino models such as the ‘Mega’ and the ‘Zero’ (still in development) have significantly more memory space (256kB flash, 32kB SRAM) and could be used for applications which do require complex programming (Arduino, n.d.).

From an organizational perspective, the Arduino also poses some difficulties. Most oceanographic instruments are designed with embedded programs, where users interact with devices using a serial communication interface (RS-232). This allows users (who are almost always separated from the design process) to configure settings without affecting the internal circuitry. Arduino boards, on the other hand, utilize a USB connection and users to upload code directly affecting the internal circuitry. The problem is twofold; one – users must adapt to an entirely new interface with devices and two – users can easily alter code that could affect an instrument’s circuitry or cause a program sequence to malfunction. To overcome these problems, managers as well as users must be open to utilizing a new interface and should employ effective change management practices in order to facilitate a transition to these instruments.

Second, designers should provide documentation explaining programs and structure program ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 25 code in a way that makes it very obvious to end users what and how variables may be changed to customize programming.

Development, production, calibration, and maintenance will likely require additional involvement from users. Additional involvement will require organizational flexibility. In order to minimize life-cycle costs, many of these functions may need to be performed by end users, rather than instrument manufacturers. Every effort should be made to simplify these processes, which by and large, should not require highly technical skills. Nonetheless, managers should recognize the implications and reserve resources before launching extensive campaigns using

Arduino-based instruments.

Lastly, it is very likely that low-cost instruments will suffer some slight loss in precision or accuracy. Modern electronic components are inexpensive, incredibly sophisticated, and may still reasonably achieve very high absolute accuracy. However, Arduino-based instruments will likely not be able to compete on a performance basis with many specialized oceanographic instruments that have been optimized by engineering professionals. A temperature sensor may only achieve an absolute accuracy of +/- 0.01°C vs. a SeaBird instrument which achieves +/-

0.002°C (Seabird Electronics, n.d.), but this must be taken in perspective. If an experiment only requires a resolution of +/- 0.01°C and the Arduino-based instrument costs only one-tenth of the price, the choice of which to use should be clear. This is not to say that all sensors will be accurate enough for all applications, but researchers should be aware of what their minimum requirements are and must be willing to forgo the most precise instruments if more economical options exist. Few studies have been done on long-term stability or reliability of Arduino boards, especially in cold conditions seen in oceanography. Such studies should be conducted for all new sensors in order to verify instrument design and alleviate concerns about reliability. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 26

Table 2 provides a summary of the major disadvantages of Arduino instruments for oceanographic instruments and the primary solutions for overcoming them.

Table 2: Disadvantages of Arduino Platform for Oceanographic Instruments

Disadvantage/Limitation of Arduino Primary Solutions

Platform

-Power consumption not optimized -Avoid deployments requiring continuous

operation.

-Include circuitry to power-down units

-Lack of memory storage -Include SDCard reader on ‘ocean shield’

-Lack of real time clock -Include RTC on ‘ocean shield’

-Built in ADC only 10-bit -Include 16-bit ADC with individual sensors

-Limited RAM -Utilize robust programming methods.

-Test all programs thoroughly before

deployment.

-Calibration and repairs not included -Develop simple calibration methods.

when manufacturing custom -Improve organizational flexibility to provide

instruments users time for servicing instruments

-New programming interface -Practice sound change management.

-Provide documentation and clear instructions

to end users.

-Mild-to-moderate reduction in -Use low-cost instruments for applications

precision when compared to requiring less precision.

sophisticated instruments -Verify long-term reliability of instruments. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 27

Applications for Oceanographic Research

As discussed in Literature Review, many instruments are already highly specialized and well suited for specific applications. Moorings and fixed systems are excellent for highly precise, long time-series benchmark data; profiling gliders and ARGO floats are ideal for wide-scale remote sampling of the deep ocean; cabled observatories may be best for real-time observation; and satellite imagery is excellent for monitoring surface conditions and geophysical processes

(National Ocean Council, 2013, pp. 21).

With such highly specialized systems, one must ponder where low-cost systems may possibly fit in the picture. Oceanographic research has evolved largely as a result of the available technology and is now heavily reliant on current systems to sustain projects vital to supporting commerce and environmental management. Unless current systems can be directly replaced by new systems with equivalent or better performance capabilities, many current programs must be continued. Given that systems have continually evolved with oceanographic research as a whole, it is reasonable to assume that many are nearly optimized, and it is unfair to assume that low-cost instrumentation could be designed for all applications. Nonetheless, abundant opportunities do exist.

One must consider the distinct advantages to low-cost sensors to understand how they may be best used. Low-cost sensors primarily provide an opportunity to deploy a large number of sensors across a region and dramatically improve spatial resolution. It is entirely possible that

Arduino-based instruments, capable of measuring a wide array of properties (temperature, conductivity, depth, nutrient levels, fluorescence, and chemical properties) can be produced for

1/10th to 1/100th of the cost of a similar suite of instruments. This effectively means that one ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 28 could possibly deploy dozens of Arduino-based instruments rather than a single traditional mooring.

Research opportunities are abundant in areas where large capital investments in instruments have previously prohibited certain processes from being studied. As such, low-cost systems are best for applications where multi-point arrays are needed such as heterogeneous regions, highly dynamic environments, or unexplored domains. Heterogeneous regions such as canyons, ridges, and shelves exhibit dramatically different conditions between physical boundaries. Large numbers of instruments may be especially useful in understanding the complex physical processes at work and how the local area is impacted as a result. Highly dynamic environments such as shallow coasts, spawning grounds, or highly productive areas can change very rapidly, making it very difficult to study transient processes. Typically such processes are studied opportunistically, only when they occur nearby to ships or established mooring sites. Instead, low-cost instrumentation may allow transient processes to be studied in a more thorough manner and possibly identify mechanisms necessary for high biological productivity. Lastly, domains that are unexplored or not well understood can benefit greatly from low-cost instruments. Deploying a very large number of instruments during the early stages of a study can help to more fully characterize a region. Once the predominant characteristics (currents, biological density, etc.) are understood, researchers may have much greater success in planning capital-intensive projects such as sophisticated mooring sites or ship- based in-situ sampling. Arctic regions are particularly notable in this respect as global interest is intensifying for expanding research to areas that are now accessible and especially intriguing due to the reduction in ice cover over recent decades. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 29

Deployment methods must also be considered for low-cost instruments in order to ensure minimal life-cycle cost. If a single $1,000 instrument on a mooring is replaced by a $100 instrument, but the ship-board deployment and recovery methods or mooring hardware is not changed, the $900 will only carry over to a minimal reduction in total cost. Researchers should consider using instruments that are expendable, deployed from smaller vessels, and/or deployed as “piggyback” projects during larger research cruises. In regard to expendable instruments,

Arduino boards can easily connect to Iridium modems that only cost around $250 and would allow instruments to relay data they have collected via satellite. Developing instruments with this Iridium communication could eliminate the need for recovery (such as with ARGO floats), thus eliminating a great deal of cost relative to traditional moorings. Expendable instruments are widely utilized, but their benefits should, of course, be weighed against the environmental impact of pollution when leaving instruments adrift or on the ocean bottom. The flexibility and small size of Arduino-based instruments may also enable the development of ‘miniature’ mooring systems that have a built-in release or can be deployed without heavy-duty equipment – possibly even by hand. Building such systems would considerably reduce deployment costs by eliminating a great deal of expensive hardware or time aboard larger research vessels. When larger vessels are needed or available, researchers should use every opportunity to “piggy-back” on pre-existing research cruises, again reducing costs by limiting ship-based time.

Low-cost instruments may be best if limited to shallower depths (say less than 200m) for several reasons. First, instruments deployed at extreme depths are subject to immense forces.

This requires each aspect of mooring systems must be robust (i.e. heavy and expensive). If low- cost instruments are largely restricted to shallow water, other components such as waterproof housings, floats, and mooring hardware can be scaled down and optimized for cost reduction. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 30

Also, considering that the deep ocean is well populated with ARGO floats; coastal regions are generally much more heterogeneous and dynamic; and a great majority of ocean productivity occurs on continental shelves at depths of 150m or less, limiting low-cost instruments to shallow depths should not significantly reduce the number of potential research opportunities.

As noted, Arduino-based instruments are not well suited for long-term deployments requiring continuous power. However, many sampling applications might only require one discrete measurement every few minutes. Researchers should be aware that Arduino-based instruments will be the most energy efficient and cost effective if used in scenarios that do not require high temporal resolution. Instruments such as ice profilers, which require measurements nearly every second to achieve an accurate picture of ice thickness, are not ideal candidates.

Alternately, since Arduinos can be easily programmed, researchers may choose to have instruments sample rapidly under certain conditions (such as during vertical profiles), but much more slowly during others. This is an equally effective method of efficient energy consumption.

Take the following scenario as an example. An Arduino-based instrument is designed which costs around $1,000 to produce and is equipped with GPS, Iridium modem, a built in release mechanism, and several oceanographic sensors. An array of instruments could then be deployed by hand via a small, fast vessel over the course of just one or two days in an area of interest, such as the Barrow Canyon in Northern Alaskan waters. The instruments could be programmed to release at a specified date after about a year, rise to the surface, and begin transmitting their data by satellite to shore. Those same instruments could easily be programmed to relay their GPS position once on the surface to collect data currents and allow them to be easily recovered when safe and economical. Researchers should endeavor to design experiments that make full use of low-cost modules and the greater flexibility they can provide. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 31

Developing a Standard Architecture (Ocean Shield)

When considering the potential research applications, the first practical step towards developing low-cost instrumentation is to overcome the major technical shortcomings of the

Arduino platform. The best way to do this is to develop what is often referred to as a “shield.”

Shields are modular circuits that usually attach directly to an Arduino board to make them immediately capable of performing certain tasks. An excellent example is a Data Logging shield. It combines a real-time clock and a micro SD card reader into a small board which plugs into an Arduino Uno and enables the board to keep track of time and record data on a removable storage device. (Adafruit, (n.d))

For the purposes of oceanographic research, one might develop an “Ocean Shield”. If an inexpensive, modular Ocean Shield is developed, it will provide an incredibly low-cost platform specifically suited for building oceanographic instruments. To serve as a functional oceanographic instrument, an Arduino board must be capable of performing a basic series of tasks. It must be able to:

1) ‘Wake-up’ at a given time

2) Take precise measurements (usually voltage levels),

3) Record data on a storage device

4) Return to a ‘sleep-mode’ (thus minimizing energy consumption).

In order to perform the above functions, a handful of standard components must be added to the Ocean Shield. Table 3 summarizes those components, their basic functions, recommended parts to use, and an approximate unit cost (as quoted on Digikey Electronics’ website (n.d.))

ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 32

Table 3: Recommended Components for Ocean Shield

Component Functions Recommended Approximate

Part Unit Cost

-Real-Time -Keep track of time and date. DS3234 $9.65

Clock -Alarm function to ‘Wake’ Unit.

-Coin Cell -Operate Real Time Clock. CR1220 or $1.49

Battery and -Minimize drain from main similar lithium

Holder battery when ‘Asleep’. cell

-Schmidt -Convert alarm signal from Real HC7S14 $0.42

Inverter Time clock to proper voltage

level to wake up device.

-Voltage -Allow unit to operate on a range LT1129 $5.78

Regulator or of voltage sources (anywhere or or

Boost Converter between 1.8V and 30V). “PowerBoost $9.95

(w/shutdown) -Allow unit to ‘Sleep’ 500 Basic”

-Precision -Provide precision voltage to MAX6126 $5.31

Voltage ADC and sensors for accurate

Regulator measurements

-Micro SD Card -Provide mass data storage Push-Push Micro $1.82

Reader capability (up to 32 GB) SD Card Slot

ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 33

Figure 2 below shows a block diagram demonstrating the basic functionality and connections for the Ocean Shield using the components in Table 3. This diagram may be used as a baseline to develop a schematic and printed circuit board for the Ocean Shield.

Figure 2: Block Diagram for Ocean Shield

Regardless if the exact parts already exist here are used or not, every component on the

Ocean Shield should operate at least in the full “industrial range” for electrical components, typically between -40°C and +85°C. Some commercial shields utilize less expensive components that only function reliably to 0°C, but oceanographic applications can easily exceed ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 34 this limit, as sea water freezes at about -2°C. Instruments are commonly used at or near these freezing conditions.

The total cost for these components adds up to $28.64 (Digikey Electronics’(n.d.)).

(However, the presented costs are for single components and can be reduced significantly if purchased in bulk.) The components must also be combined and assembled onto a small printed circuit board, which adds some cost. Given these prices and the average prices of other available shields (Adafruit, n.d.), one could reasonably expect to create an Ocean Shield that would cost at most $50.

Including the $25 cost of an Arduino Uno, this means one could conceivably purchase a platform fully equipped for oceanographic instruments for about $75. Additionally, that $75 platform would be ideally suited for the types of research applications described above and would easily be able to interface with numerous sensors, incurring minimal marginal costs for each.

The above-described architecture should be suitable for standard oceanographic instruments. However, for some specialized applications, the Arduino Uno and its accompanying Ocean Shield may not be fully adequate. Using other Arduino boards may be slightly more expensive and will require some additional engineering in order to replicate the higher functionality of the Ocean Shield, but still may be viable low cost solutions given the parallel design features. Fortunately, other models of Arduino boards can be utilized with very few modifications to sensors or program code. For instruments where size and power are especially important constraints, designers can use the TinyDuino (or similar modules), which are “as powerful as the Arduino and smaller than the size of a quarter” (TinyCircuits, n.d.). For applications which require complex programming algorithms or more than a ten sensors, ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 35 designers may utilize a module such as the Arduino Mega. The Mega is a physically larger board but has 256kB of flash memory, 32kB SRAM, and 54 digital pins - compared to 32kB of flash memory, 2kB SRAM, and 20 digital pins on the Arduino Uno (Arduino, n.d.). These types of specialized applications do hold potential but are probably best investigated after standard

Arduino-based instruments are better established. Figures 3 and 4 depict the TinyDuino and

Arduino Mega, respectively.

Figure 3: Photo of the TinyDuino (Tiny Circuits, n.d.)

Figure 4: Photo of Arduino Mega (Arduino, n.d.)

Sensor Design

Once the basic architecture for Arduino-based instruments is created (the Ocean Shield), developers can easily engage in the process of creating individual low-cost sensors. (A few example concepts have already been published and are discussed in the Literature Review). The benefit of creating a standard architecture is that developers can engage in rapid prototype development - testing and characterizing individual sensors much more quickly. Additionally, once individual sensors are developed, they can be seamlessly integrated into formal oceanographic instruments using the same architecture, thus bypassing a sizeable portion of engineering design costs. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 36

The OpenROV IMU/Compass/Depth Module is a superb example of the form these individual sensors may take (OpenROV, 2015). An assembled module costs $80.00 and combines a pressure sensor (for depth) and a 9-axis Inertial Measurement Unit (providing heading, roll, pitch, and rotational rate). These components are assembled in a tidy package and encased in an acrylic housing to protect the sensor – the sensor is shown in Figure 5 below

(OpenROV, 2015). Additionally, all signals flowing to and from the sensor are digital, which dramatically reduces the potential for error from analog signal transmission. This can be accomplished in all sensors by using integrated circuits or including individual analog-to-digital converters in close proximity to analog sensors.

Figure 5: OpenROV IMU/Compass/Depth Module (OpenROV, 2015)

A number of traits must be characterized for each type of sensor in order to fully integrate them into oceanographic instruments. Studies should be completed to determine attributes including initial accuracy, precision, measurement range, reliability, annual drift, and resistance ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 37 to biofouling. Projects to characterize a single type of sensor in this manner or optimize sensor quality based on a variety of configurations or materials are sizeable undertakings. Developers should endeavor to thoroughly test these qualities and perform studies so that sensors can be seamlessly integrated into instruments – simply demonstrating a proof of concept and measuring data for a short deployment is not substantial enough evidence to rely on data for formal oceanographic studies. Accordingly, it would be advantageous if students and researchers continue to focus on developing a single type of sensor at a time, rather than attempting to build new, complete instruments during each study. Focusing on individual sensor design will support collaborative development, standardization across design groups, and modular design – all of which should reduce life-cycle costs.

Additionally, developers should make efforts to determine inexpensive and simple methods of calibrating instruments. If low-cost instruments do see a small reduction in precision, it is very likely that calibrations could be performed by comparison to commercial instruments with a single or double point reference, or by possibly a directly mapping all voltage readings to true values. Simple calibration methods are also essential when producing large numbers of instruments to ensure time commitments for procedures are not prohibitive.

User Interaction Design

Consideration must also be given to how both developers and end-users will interact with

Arduino instruments. The Ocean Shield should do a great deal to the reduce complexity of hardware for developers. Developers will also be expected to be much more familiar with the software interface and spend a significant amount of time adjusting settings or writing code - thus, software is not likely to cause a great deal of problems for developers. End-users, on the other hand, might have little or no experience using the Arduino programming environment. To ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 38 alleviate problems, developers should make every effort to write code with names and function calls that make very clear what the program code is doing. Developers are also highly encouraged to thoroughly comment code to this end. As for hardware, end-users should also be provided some visual or auditory confirmation that instruments are operating and loaded properly if possible. Arduino boards themselves have no built functionality for this purpose, and it can be difficult for first-time users to understand how the devices operate. Lastly, in regards to both hardware and software, developers should give detailed attention to user instructions for product assembly, programming, calibration, and repair/maintenance procedures. End users who have not used the Arduino platform before may be required to interact more with low-cost instrumentation to reduce costs – a matter that will only magnify the importance of proper documentation and training.

Sharing and Distributing Information

A common method of sharing and distributing information should also be given particular attention. Low-cost instrumentation with the Arduino’s open-source design will benefit most from collaborative development where assorted sensors are developed simultaneously diverse groups of students and research institutions, rather than a centralized product development team. Consequently, those groups need to have some system for sharing design plans and studies on various types of sensors. The most obvious and probably most effective solution would be to create a centralized website for all Arduino-based oceanographic instruments.

A centralized website should contain standardized information wherever possible and be organized in a logical format according to sensor or instrument type. Users should be encouraged to utilize standard software for designs and thoroughly document their results. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 39

Schematics, circuit board drawings, program code, component lists, findings, and any academic publications should all be included in every possible circumstance. Users should also be able to engage in discussions and upload content as they participate in studies. In order to protect the integrity of designs and studies published to the page, the information should also be subject to review by a program and/or site manager.

ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 40

Summary

Arduino-based instruments hold great promise for realizing successful, low-cost instruments. Though they are not a universal solution to replacing all traditional instruments, they can provide opportunities for reducing the costs of many instruments by an order of magnitude or more and open doors to new research endeavors in the process.

The primary strategies described above which will result in successful implementation of low-cost sensors are as follows:

1. Develop an Ocean Shield to optimize Arduino functionality for oceanographic

applications.

2. Design downstream operations, maintenance, and calibration procedures for low-cost.

(Consider more than just acquisition costs)

3. Design and characterize individual modular sensors before developing complicated

instruments.

4. Consider user interaction for programming structure and downstream processes.

5. Centralize sharing and distribution of design materials and results on a managed

website.

One difficulty in developing this implementation strategy was identifying and addressing roadblocks which have thus far prevented low-cost instruments from becoming a reality. From an organizational perspective, challenges concerning reducing life-cycle costs, maintaining data quality, and altering traditional methods are, in reality, very complex and intertwined. The main focus of this strategy was not to develop an exhaustive solution which will overcome every challenge in the development of low-cost instruments. Instead, it was designed to present a ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 41 methodology and specific technical recommendations for a solution that can overcome the major challenges and to demonstrate the feasibility of such a solution.

Researching the most recent advances in low-cost instrument design also proved to be difficult. With the rapidly evolving technology of the day, new design proposals are constantly being presented – many just in the year prior to the presentation of this strategy and likely many more underway. This difficulty highlights the need for a centralized database or website for sharing information. Similarly, various designs utilized different architectures and assessed different aspects of their feasibility, rarely giving much discussion to how they might actually be implemented other than demonstrating that they ‘can be cost effective.’ On one hand, this emphasized the need for an implementation strategy and standardized designs. On the other hand, it made trying to propose a standard architecture that would work across a variety of applications very difficult. Envisioning realistic applications for low-cost instruments helped to narrow the field and propose an architecture which would function well for those situations.

In order to determine specific applications for Arduino-based instruments, it would be very useful to first interview scientists about potential research opportunities. The strategy here can be used as a framework to generate questions. What applications may benefit from high spatial resolution studies? Where can traditional instruments be replaced by cheaper instruments with slightly reduced data resolution? Can you provide users with additional time for training and interaction with instruments if it means dramatically reducing material costs? Once several example applications are identified, developers can work more closely with researchers to develop prototypes and begin reliability testing. These discussions would also serve to open communication channels with researchers, making them more open to accepting Arduino-based ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 42 technologies for their work. Interviews could be conducted on an individual basis by a dedicated team, or during a multi-disciplinary round table discussion.

In regards to individual sensor development, low-cost designs have already been proposed for a variety of parameters. Thermistors can be used for temperature; LED excitation for photosynthetic ambient radiation, fluorescence, and pH; and strain gauges for pressure/depth.

One critical parameter is still missing for oceanography – conductivity. Conductivity can be highly troublesome because the most sensitive sensors are those with electrodes which are in contact with a liquid solution. Since instruments are used in highly corrosive, conductive environments, they are highly susceptible to biofouling unless built with expensive materials.

However, toroidal sensors which are usually encased in a polymeric material are highly resistant to biofouling and require a great deal less maintenance (Down & Lehr, 2005). Low-cost instrumentation would take a huge leap forward if a very inexpensive (<$200), modular conductivity sensor (most likely a toroidal cell) could be developed, ideally using COST electronic components. This development would facilitate standard oceanographic studies using

CTD profiles and dramatically increase the number of potential applications for low-cost instruments.

The development of low-cost instruments could also benefit from a formal analysis of life-cycle costs for various current traditional instruments. For example, how much does a fluorometer cost for a 20-year period when including acquisition costs, semi-annual repairs, calibrations, shipping, mounting hardware, and mooring equipment. A formal analysis would improve transparency of how much instruments truly cost, give more support to the need for low-cost instruments, and provide developers with more accurate price targets for low-cost designs. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 43

Lastly, although a great deal of development on Arduino-based instruments can be done collaboratively by geographically disparate groups, the overall project would benefit greatly from a small centralized group to manage and guide the process. A small group would be able to manage a website for collecting and distributing plans, provide support to new designers or researchers, summarize and broadcast new developments, and offer recommendations for future growth. Some processes, such as printed circuit board manufacturing and certain calibrations may also be the most cost effective if centralized in a single location. Any oceanographic research institution which has multiple laboratories that could benefit from low-cost instruments should take leadership and initiate the formation of such a group.

ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 44

References

Adafruit. (n.d.). Adafruit Assembled Data Logging shield for Arduino. Retrieved March 2,

2015, from http://www.adafruit.com/product/1141

Adafruit. (n.d.). Adafruit Assembled Data Logging shield for Arduino. Retrieved February 2,

2015, from http://www.adafruit.com/products/1141

Adafruit. (n.d.). Arduino Uno R3. Retrieved February 2, 2015, from

http://www.adafruit.com/products/50

Adafruit. (n.d.). Ultimate GPS Module - 66 channel w/10 Hz updates - MTK3339 chipset.

Retrieved February 2, 2015, from http://www.adafruit.com/products/790

Adafruit. (n.d.). XBee Module - ZB Series 2 - 2mW with Wire Antenna - XB24-Z7WIT-004.

Retrieved February 2, 2015, from http://www.adafruit.com/product/968

Anzalone, G. C., Glover, A. G., & Pearce, J. M. (2013). Open-Source Colorimeter. Sensors,

13(4), 5338-5346.

Arduino. (n.d.). Arduino Home - What is Arduino? Retrieved from http://www.arduino.cc/

Arduino. (n.d.). Arduino Mega 2560. Retrieved March 2, 2015, from

http://arduino.cc/en/Main/ArduinoBoardMega2560

Arduino. (n.d.). Arduino Uno. Retrieved March 2, 2015, from

http://arduino.cc/en/Main/arduinoBoardUno

Arduino. (n.d.). Arduino Zero. Retrieved March 2, 2015, from

http://arduino.cc/en/Main/ArduinoBoardZero

Arduino. (n.d.). ArduinoUno R3 Front. Retrieved from

http://arduino.cc/en/uploads/Main/ArduinoUno_R3_Front.jpg

Argo FAQ. (n.d.). Retrieved from http://www.argo.ucsd.edu/FAQ.html

Argo FAQ. (n.d.). Retrieved from http://www.argo.ucsd.edu/FAQ.html ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 45

Beaton, Alexander D., Cardwell, Christopher L., Thomas, Rupert S., Sieben, Vincent J.,

Legiret, François-Eric, Waugh, Edward M,… Morgan, Hywel (2012) Lab-on-Chip

Measurement of Nitrate and Nitrite for In Situ Analysis of Natural Waters.

Environmental Science & Technology, 46, (17), 9548-9556.

Blanchard, B. S. (2008). System engineering management. Hoboken, NJ: Wiley.

Cagan, M. (2008). Inspired: How to create products customers love. Sunnyvale], CA: SVPG

Press.

Chave, A. D., Waterworth, G., Maffei, A. R., & Massion, G. (2004). Cabled Ocean

Observatory Systems. Marine Technology Society Journal.

doi:10.4031/002533204787522785

Digikey Electronics. (n.d.). Product Index. Retrieved March 2, 2015, from

http://www.digikey.com/product-search/en

Eriksen, C. C. (1997). Instrumentation for Physical Oceanography: the last two decades and

beyond.

Johansen, J. L. (2014). Quantifying Water Flow within Aquatic Ecosystems Using Load Cell

Sensors: A Profile of Currents Experienced by Coral Reef Organisms around Lizard

Island, Great Barrier Reef, Australia. PLOS ONE, 9(1), e83240. Retrieved from

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0083240

Kelley, C., Krolick, A., Brunner, L., Burklund, A., Kahn, D., Ball, W., & Weber-Shirk, M.

(2014). An Affordable Open-Source Turbidimeter. Sensors, 14, 7142-7155.

Leeuw, T., Boss, E. S., & Wright, D. L. (2013). In situ Measurements of Phytoplankton

Fluorescence Using Low Cost Electronics. Sensors, 13(6), 7872-7883. ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 46

Maffei, A. R., Chave, A. D., Grabeal, J., Edson, J. B., Fredericks, J. J., Ammerman, J. W., &

Hanisch, R. (n.d.). Building Standards for Access to Oceanographic Observatory

Instrumentation. Retrieved from

http://www.interactiveoceans.washington.edu/files/ssc03.ioop.pdf

NOAA - Office of Exploration and Research. (April 16, 2013). Observing Systems and

Sensors. Retrieved March 30, 2015, from

http://oceanexplorer.noaa.gov/technology/tools/tools.html

National Ocean Council. (2013). Federal Oceanographic Fleet Status Report. Retrieved

from Executive Office of the President website:

http://www.whitehouse.gov/sites/default/files/federal_oceanographic_fleet_status_rep

ort.pdf

National Ocean Service. (2001). Ocean Systems Test and Evaluation Program (OSTEP)

Development Plan. Retrieved from NOAA website:

http://tidesandcurrents.noaa.gov/publications/techrpt34.pdf

National Research Council (U.S.). Committee on an Ocean Infrastructure Strategy for U.S.

Ocean Research in 2030. (2011). Critical infrastructure for ocean research and

societal needs in 2030. Washington, DC: National Academies Press.

OpenROV. (2015). OpenROV IMU/Compass/Depth Module. Retrieved March 30, 2015,

from http://store.openrov.com/products/openrov-imu-depth-module

Paradis, R. (2013). NAVSEA/FIT - ECS Unit (Master's thesis). Retrieved from

http://my.fit.edu/~swood/Rick_Paradis_Thesis.pdf

Rock Seven. (n.d.). About RockBLOCK. Retrieved February 2, 2015, from

https://www.rock7mobile.com/products-rockblock ARDUINO-BASED OCEANOGRAPHIC INSTRUMENTS 47

Seabird Electronics. (n.d.). SBE 56 Temperature Logger. Retrieved March 2, 2015, from

http://www.seabird.com/sbe56-temperature-logger

Talley, L. D., Pickard, G. L., Emery, W. J., & Swift, J. H. (2011). Descriptive physical

oceanography: An introduction. Amsterdam: Academic Press.

Thaler, A., & Sturdivant, K. (2013). Oceanography for Everyone - The OpenCTD. Retrieved

from http://www.rockethub.com/projects/26388-oceanography-for-everyone-the-

openctd#description-tab

TinyCircuits. (n.d.). Learn & Shop The TinyDuino Platform. Retrieved March 2, 2015, from

https://tiny-circuits.com/products/tiny-duino.html

Turner Designs. (n.d.). Cyclops-7™ Submersible Sensors. Retrieved from

http://www.turnerdesigns.com/products/submersible-fluorometer/cyclops-7-

submersible-fluorescence-and-turbidity-sensors

Venture Beat News. (2013, April 8). Liquid Robotics launches new generation of wave

glider ocean robots. Retrieved from http://venturebeat.com/2013/04/08/liquid-

robotics-launches-new-generation-of-wave-glider-ocean-robots/

Virginia Institute of Marine Science. (2012, March 22). What is the monetary value of a

healthy ocean?. ScienceDaily. Retrieved March 30, 2015 from

www.sciencedaily.com/releases/2012/03/120322100417.htm

Woods Hole Oceanographic Institute. (2007). Conductivity, Temperature, Depth (CTD)

Sensors. Retrieved from www.whoi.edu/page.do?cid=1003&pid=8415&tid=282

Yang, B., Pastavas, M., Byrne, R., & Ma, J. (2014). Seawater pH measurements in the field:

A DIY photometer with 0.01unit pH accuracy. Marine Chemistry, 160, 75-81.