Our system works as a mesh network, to relay the data between nodes until it reaches an access point where it is sent to the internet for analysis. This allows for many low cost modules to be connected to the web, through one module (gateway) with the equipment needed to connect to the internet.
Currently, data on water conditions is retrieved manually, which presents a large roadblock as only a small area of a water system could be measured, and in our case, only a small handful of Minnesota’s more than 10,000 lakes can be looked after. Also, water quality trends can only be observed on a yearly - or even less often basis. Adding a mesh network of sensors that can provide test results much more often will allow us to observe trends throughout a day, as the sun rises and sets and effects the chemistry of the waterway, or as the season changes, changing the conditions of the surrounding environment. Being able to observe the waterways reactance to these environmental conditions would provide far more insight than current data collection methods. Being able to collect this data throughout a waterway will also allow for us to pinpoint problematic areas in a waterway that can be addressed to impact the overall health of that ecosystem.
Back in 2014 Lake Erie was hit with a large toxic algae bloom, spurred by levels high levels of phosphors from farms on around tributaries that fed into the lake. This led the city of Toledo to shut down the cities water supply, leaving residents without running water, and this is not an isolated case. It has happened numerous times in the past and the Chesapeake Bay region often faces a similar issue. A system like this could help narrow down the main contributors and of an outbreak similar to this before it happens.
The main circuit board, responsible for communication and sensor readings, includes a UBLOX low power GPS for location and time services, a LoRa radio transceiver for communication between nodes, and breakout connectors for a wide variety of sensors, adjustable to the current application. These sensors include pH, conductivity, Oxygen and Nitrogen, turbidity, hardness, and temperature sensors.
Our system would be deployed the same package of standard sized buoys that you would see on a lake or river. To achieve a very low cost of construction and high durability for years of operation, we chose to go with a 3 piece design with a hard plastic outer shell, holding a two piece insulated foam core with the electrical components housed inside. A solar panel is installed on the top of the payload to extend the life of the unit, with a channel running down the center for the connection to the panel and housing for the antennas for the radio and GPS units. Sensors would then be embedded in the bottom of the buoy, protected, while depth dependent sensors like multiple temperature sensors would come out the bottom and be held down by the anchoring cable.
What sets us apart from other entries is that we have experience in radio communication with microcontrollers and developing portable systems, specifically with LoRa radio modules in partnership with antennas that need to be reliable, as a part of a group researching and developing long duration weather balloons that last days at a time in harsh conditions of the upper atmosphere. We also have experience working with an overhead power limitation, and different ways to deal with those power limitations in harsh environments, including warm and cold conditions where a few small batteries won’t make the cut.
