* You are viewing the Search Results for "OWHL"

Updated OWHL assembly video

I have revised the Open Wave Height Logger electronics assembly video as of March 2020 to include narration (uh-oh) and more information about the programming process and error codes. This video outlines the entire assembly process for soldering the components to the 3 circuit boards of the OWHL Revision C design. The current designs and software to run the OWHL can be found at the OWHL Github repository.

A permanently archived copy of this video can … Continue Reading

OWHL micro SD card current draw tests

As outlined in an earlier post, I found that certain old micro SD cards were performing spectacularly poorly when it came to power consumption because they failed to go into a low-power sleep state immediately after writing data to the card. I recently purchased a few new SanDisk micro SD cards in various capacities to see how they behaved. I purchased 4GB, 8GB, 16GB, and 32GB SanDisk cards from Amazon in November 2014. These were all tagged as “Ships from and sold by Amazon.com” and ranged from $5.99 to $12.99.

The good news is that all 4 cards behaved properly … Continue Reading

Open Wave Height Logger paper

After a prolonged period of development, we’ve finally put out an article in Limnology and Oceanography: Methods detailing our Open Wave Height Logger project (OWHL). This paper walks through the motivations for the project (low-cost, long-duration water pressure data logging so that we can know what the waves were like at a field site) and the variety of tests we went through during development.

The paper itself is freely available via open access here: http://dx.doi.org/10.1002/lom3.10370Continue Reading

Open Wave Height Logger revision C

The Open Wave Height Logger (OWHL) project has reached another minor milestone with the release of a new hardware revision, RevC.

This is a redesign of the three printed circuit boards, breaking physical compatibility with the older revisions, but it maintains software compatibility with the existing OWHL code (hardware designs and code available at the GitHub repository: https://github.com/millerlp/OWHL). The goal was to make the hardware a bit easier to assemble, and make certain parts (the micro SD card) easier to reach. All of the tiny surface mount components, save a few, are now on a single side of each … Continue Reading

Open Wave Height Logger prototype in the water

I finally got around to deploying a prototype OWHL unit in the real live ocean to log some waves.

The low-tech housing is made of 1.5″ schedule 40 pvc pipe. The pipe snugly fits the D-cell battery holder, while the electronics fit inside the modified 1.5″ end cap.

Components of the housing. Assembled prototype housing

I try not to rely solely on the tapered threads … Continue Reading

Revised Open Wave Height Logger battery tests

The Open Wave Height Logger is meant to be a submersible pressure logger that will record absolute pressure at 4Hz for several months to give a record of wave height, and ideally do this on a single set of 3 D-cell batteries. I have recently made a few changes to the OWHL software, and discovered a major flaw in my original battery test. As a result, I have begun a new round of battery tests. The hardware and software changes are described here, and new battery test results are shown at the bottom of the … Continue Reading

Early Open Wave Height Logger battery tests

The Open Wave Height Logger prototype stack.

Following on the previous post about the Open Wave Height Logger project, I’ve been conducting a simple battery life test. One of the prototype OWHLs was powered by a 3 D-cell alkaline battery pack and shoved in the freezer for 32 days. The image below shows the collated daily data files for that time period, during which the data logger was sampling 4 times per second continuously. The black line is pressure in millibar, and … Continue Reading

Open Wave Height Logger

OWHL – The Open Wave Height Logger
OWHL is a project originally dreamed up by Jarrett Byrnes and Ted Lyman at UMass Boston. Early on they contacted me for my thoughts on how to accomplish the goal of making a cheap, long-life pressure sensor data logger that could be used to record ocean wave heights near shore. I joined the effort during the initial specification stages. Ideally this device could be mounted on the seafloor at ~10 meters depth offshore, and record surface waves at 4 Hz for many months, with data saved to a micro SD card in a … Continue Reading

CV/Publications

A current CV is available here:  Curriculum Vitae [pdf]

Publications

31. Lyman, T., K. E. Elsmore, B. Gaylord, J. E. Byrnes, and L. P. Miller. (2020) Open Wave Height Logger: an open source pressure sensor data logger for wave measurement. Limnology and Oceanography: Methods 18: 335-355

30. Elahi, R., L. P. Miller, and S. Y. Litvin. (2020) Historical comparisons of body size are sensitive to data availability and ecological context. Ecology v101 n9: e03101.