Solar-Powered IoT Buoy Blends STEM Education and Scientific Research
Tom Lombardo posted on September 21, 2018 |

The Great Lakes, glacial relics of Earth's most recent ice age, contain more than one-fifth of the world's fresh surface water, providing edibles, potables, irrigation, recreation, and revenue to the nearly sixty-million people living in the region. Scientists, engineers, and educators are teaming up to ensure the long-term sustainability of these vast inland seas and to cultivate the next generation of scientific thinkers. Among the tools contributing to the endeavor: solar-powered buoys with a slew of instrumentation, a publicly accessible web portal, and a series of STEM-based lesson plans aligned with state academic standards.

Where the Buoys Are

Sensor-laden buoys are scattered throughout the Great Lakes region, anchored to the seafloor in strategic locations. These waterborne IoT devices send a constant stream of data to the web, allowing researchers, students, and the general public to monitor current lake conditions.


One of them, the Michigan City Buoy, is located on the southern tip of Lake Michigan. It's sponsored by NOAA's Sea Grant program and operated jointly by the University of Illinois and Purdue University.

Michigan City's TIDAS 900 monitoring buoy includes sensors that measure and record wind speed and direction, air temperature, air pressure, humidity, wave height and period, and water temperature at various depths. The unit is powered by onboard batteries that are charged by solar panels.

I contacted Hope Charters, communications coordinator with the Illinois-Indiana Sea Grant, to inquire about the buoy's technology. My technical questions were answered by Cary Troy and David Cannon of Purdue Civil Engineering, buoy partners, and the curriculum question was answered by Terri Hallesy, Illinois-Indiana Sea Grant Education Coordinator.

What type of solar panels does the buoy use and what are their power ratings?

Our larger buoys (45170 and 45174) are TIDAS 900 monitoring buoys. They each have six solar panels: three on the upper mast (10W Mono-Crystalline) and three on the lower hull (15W Mono-Crystalline).


Does it use a battery so it can record data at night? If so, what type and capacity is it?

It sure does! Each buoy uses twelve 12V 3.4AH sealed lead-acid batteries, for a total capacity of 40.8 AH.


How does it measure wave height?

Wave heights are measured using an inertial wave sensor designed by the University of Michigan Ocean Engineering Laboratory. The sensor uses a three-axis accelerometer coupled with a digital compass to compute heading, wave height, wave period, and wave direction. Wave parameters are extracted from raw accelerometer data using a fast Fourier transform algorithm.


How does it communicate its data?

The data collected by each buoy is transmitted to several groups, including Illinois-Indiana Sea Grant (IISG), the National Data Buoy Center (NDBC), and the Great Lakes Observing System (GLOS). This data is processed on the buoys using a Campbell Scientific data logger (CR1000) before using an onboard modem to transmit the data over a cellular network.


Is the curriculum aligned with Common Core standards?

The curriculum is aligned to Indiana State Science Standards, Next Generation Science Standards, and the Great Lakes Literacy Principles when applicable, and are listed on the first page of each activity.

The Data

The buoys provide information that enhances weather forecasting, boating, as well as commercial and recreational fishing. Specifically, wind speeds and wave conditions can let boaters know whether it's safe to go out on the water, and water temperatures at various depths can help anglers choose the best spots are for fishing that day. Measurements are taken at ten-minute intervals and sent, via cellular connection, to a portal server.

STEM Lessons

Science educators at the University of Illinois and Purdue University created a set of STEM-based lessons for students in grades six through twelve. These aren't simple worksheets; they're complete lesson plans, including clear objectives, background information, activities, discussion questions, assessment criteria, and teaching suggestions. The topics cover science, math, and communication skills. The first lesson asks students to create a "Save the Great Lakes" ad campaign. Students must gather information (including buoy data), determine its relevance, organize the data, and present it in the form of an infographic. Pedagogically speaking, working on a real-world project is one of the best ways for students to become engaged and motivated to learn. And presenting the results graphically, as opposed to writing an essay or research paper, helps students to approach new information with multiple modalities (e.g., visual, auditory, and text.)

Additional lessons involve conducting experiments, analyzing and presenting data, developing and testing hypotheses, making predictions based on tables and graphs of data, and working with spreadsheets.

As an instructional designer and seasoned educator, I'm impressed with the curriculum that the team has created, especially the emphasis on presenting data in a readable format—a skill that many technically-minded people seem to lack. I would, however, like to see a few lessons leaning toward the engineering and technology side. For example, solar radiation charts can be used to calculate the amount of solar energy available to a buoy. From there, students can look up the data sheets for the solar panels to determine how much electricity they generate on an average day. Next, they'd find out how much power the onboard electronics use, and finally, they could spec out the battery capacity needed to run the buoys overnight and through several days of cloudiness. They could even evaluate different types of batteries to see which is the best for this application.


Can you think of other engineering lessons based on these buoys? Please comment below.

Bringing Science to the Public

In an age driven by technological advancements, scientific literacy among the general population is crucial. Unfortunately, science is often treated as a spectator sport, leaving the public on the sidelines with little understanding about what's happening on the field. American sports leagues are trying to increase interest by creating fantasy leagues, where fans pore over statistics and read expert analyses in order to field the best hypothetical team. I'm not sure "fantasy science" would fare quite as well, but providing actual scientific information to the public could at least raise awareness and engagement levels, especially if it's introduced at a young age.

Amateur comet hunters, storm chasers, and bird watchers have made significant contributions to our understanding of nature. Although science has become highly specialized, the slew of instruments that now reside on the Internet of Things gives the public even more access to live data, providing armchair scientists with greater opportunities to add to the knowledge base. It's time to put that technology to better use through more partnerships between science, engineering, and education.

All images courtesy of Illinois-Indiana Sea Grant.

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