MenomiNet: A Prototype Network for Real-Time Public Lake Data

Abstract

Why the MenomiNet?

Without knowing where the Lake Menomin problem is at its worst, we’re unable to avoid the worst consequences of water contamination–risks to human health. We can’t use remote satellite imaging on the lake because blue green algae coat the surface and prevent the use of depth analysis imaging techniques. In fact, instead of a satellite-scale project, the project that will teach us the most about Lake Menomin, in the quickest, cheapest, and most efficient manner is a DIY monitoring system.

This past summer, we worked on this wireless network of water quality buoys, successfully getting one transmitter and one receiver node out onto the water. In future years, the network will expand its capability for distance communication and full remoteness. We used parts one could acquire for a relatively low-cost relative to the payoffs of the amount of data and the lifetime of the sensors (if contained well within a properly waterproofed buoy.) Accessibility was a key consideration of ours as we wanted citizens to try and collect data themselves, if not for the greater lake issue, then just for an entertaining home project in the neighborhood pond.

Lake health can forecast other forms of ecological health in the area, and especially in Wisconsin, where many individuals are employed in the agricultural industry, learning firsthand through how the impactful watershed quality is to one’s farm can perhaps motivate a change in practices or a reduction in resource inputs, to the triple benefit of the farmer, the rest of the community, and the environment.

Everyone I met this summer has an opinion on what should be done with the lake. Quite a few push for a “big solution” to be implemented now such as dredging the entire lake. Others advocate for us to take a step back and explore different strategies, especially considering that it was only very recently that nitrogen was identified as a greater issue in the watershed than phosphorus. Due to funding constraints and public and expert opinion, the second route is running its course. In the meantime, while we’re waiting for a consensus, we don’t have to sit on our hands. We can collect data in real-time that will allow us to pinpoint where and what to address first in the lake.

Further Thoughts for the Interested DIY Builder

For those who would like to replicate our research, we encourage the use of directional antennas and adapting transmitters as relays. Additionally, we found that other modules such as Draguino were advantageous to use because it was less work to push to a website, however there was an inability to customize the data on the website in a nice format for the purposes of water quality monitoring. With regards to the code, the most frequent issue my partner and I ran into is multiple transmissions going off at the same time. We found two points of error, one with the code (our loop wasn’t working properly), and one with the physical setup (digital and analog transmissions were somehow interfering with each other–we still don’t know why.) We changed the data type we used from an array of nonspecific characters to an array of integers and increased the delays to improve signal transmission rates and prevent multiple sensor transmissions from interfering with each other and messing up communication. We experimented with having each transmitter remain in a relay mode, pushing out the same data for a certain timestamp, though we ultimately chose to collect data much more frequently than researchers or biologists would use it because we wanted to ensure that our marsh environment wasn’t tampering out Some advances that we look forward to is more buoys getting out there(they will be waiting in the engineering building at Stout until then!).

A last piece of advice we’d have for the homebuilder is to prioritize effectively. For instance, minimizing the amount of contact points between bucket and PVC reduces failure because it increases waterproofing, sans extra silicone or coating. Another concern was insulating wires, which we achieved by using shrink tubing and silicone smeared at the edges of the housing unit. We began with a less ambitious project in which our sensors were not very far from the buoy (they were in fact contained within the buoy) but in the future, in order to measure the thermocline (a level at which the lake separates into two separate lakes (in essence), the home builder might consider extending their sensors outside of the buoy for data collection at depth.