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Open-Learning to Open Water: An Experimental Course Leads to Experiments in the Field

February 4 2015

Four undergrads at UMass Amherst are using Independent Study for the construction, testing, and initial research using and OpenROV v2.6. Mounted sensors will measure dissolved oxygen, depth, temperature, and location. Funding is greatly appreciated!

February 4 2015


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Name: Daniel Smoliga
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Preparation Stage

The project has been progressing very slow these past few weeks. We have been troubleshooting the same issue for more than a month: the motors do not behave as they have been programmed to.
A while back, Leif and I were programming the Electronic Speed Controllers (ESCs) and no matter what we tried, the motors seemed to have a mind all their own; one or two would run constantly, two would behave as programmed while the third did nothing, etc. We finally got to a point where we were able to control all three motors, but the starboard motor would spin at a lower speed than the port motor. This led us to believe that this might be a power issue or a faulty ESC, if not a damaged motor or motor wiring.
However, before we started to take the ROV apart, we took one more attempt at programming the ESCs with a newly acquired ESC programming card (a highly recommended $12 investment). Inexplicably, all three motors spun at the same rate! Now we are sure it is a programming issue, but the ESCs, or the commands coming from the Arduino controller board, or even the BeagleBone?
Enter: The Logic Analyzer! This great little gadget can be connected to specific pins, ports, and terminals on a circuit or board so that the digital signal, analog signal, or data protocol can be captured, displayed, and analyzed. We connected the analyzer to the pins on the Arduino board where the ESCs connect to, and have been able to prove that there are incorrect signals coming from the board. That's the good news (sort of?). The bad news is that we can't tell right now if the faulty signaling is coming from the Arduino or the Beaglebone. Leif spent some time using Putty to access the lists on the Beaglebone that contain the programming, but to no avail.
In the meantime between those efforts last week and our next meeting this coming Friday, Leif is going to find out how to access those files so that we can analyze the code and possibly find out what is causing the faulty signaling. While he is doing that, Ryan Putt and Adam Ells are putting together a user manual for the Dissolved Oxygen sensor and procuring a location for us to calibrate and test it. I will be learning how to calibrate the D.O. sensor while I wire it up to an Arduino. If the issue can't readily be resolved with the ROV, we will make progress by proving the sensor equipment!

I'm really looking forward to this DO sensor! Good luck with your ROV, you may have a grounding issue. If the enamel on the copper coils gets nicked sometimes it will ground straight to the motor mounting plate. Check connectivity between the motor mount and each of the three motor leads. If you have connectivity, you have a grounding issue. I usually just dig a point of the voltmeter lead into the insulation on the motor wires, and then cover it in hot glue when I'm done.

Expedition Background

At the University of Massachusetts Amherst, an innovative upper-level undergraduate course with an active, team-oriented, problem-based learning course was recently created. I has a "flipped" style of content learning where students would find and utilize online open access material and relevant project technologies to solve or study an environmental issue. What started out as three students with a goal of monitoring dissolved oxygen levels and turbidity in a local water body using a small boat controlled by an Arduino with a Roomba-like algorithm and a few sensors has blown up into something much bigger.
After seeing the OpenROV kit and a Maker Faire, it was decided we needed one, so investors were sought and found in the Department of Environmental Conservation (UMass Amherst College of Natural Sciences). The majority of the funds were provided by Dr. Allison Roy, Dr. Adrian Jordaan, and Dr. Andy Danylchuck, who will be taking possession of the built and tested ROV for use in their fish ecology research.
The initial team from the class was comprised of Thais Correia (a Computer Science major from Amherst College), Leif Dickison (an Environmental Conservation major at UMass), and Daniel Smoliga (a Mechanical Engineering major at UMass). They built and programmed the ROV which they dubbed SALOR (Submersible Autonomous Liquid Oxygen Reporter) as far as they could in roughly half of a semester. Leif and Daniel are continuing the build with the aide of two other undergrads: Ryan Putt (Environmental Conservation) and Adam Ells (Natural Resource Conservation). Ryan and Adam will be learning how to operate and maintain the ROV when Daniel and Leif graduate.
Once the build is finished, a variety of sensors will be added and tested; those sensors include dissolved oxygen, pressure (depth), temperature, and compass heading. The tests will first be conducted in controlled conditions (e.g. water tunnel or pool), followed by tests and basic research in local fresh-water bodies. Following this testing phase, the ROV will be handed over to the professors for use in their research. Some of this research includes the behavior and habitats of two species of river herring, bluebacks (Alosa aestivalis) and alewife (Alosa pseudoharengus), as they spawn, hatch, and mature in the rivers and streams of Cape Cod, Massachusetts before returning to the Atlantic Ocean for their adult lives; counting mussels in lake littoral areas in the summer to investigate the effect of annual winter lake drawdowns on habitat and biota.