In July 2016 Sensemakers started a project to measure several aspects of the water in the Marineterrein. Bureau Marineterrein asked us if we could build a solution to indicate whether the water was safe for swimming. With events like the yearly City Swim and the idea to turn the Marineterrein into a more recreational area, this was of great importance for them.
At a kick-off workshop many things were tried and resulted in some funny designs. However, when we looked more into the details of water quality with the help of Waternet, it quickly became clear that there would be no easy solution.
Still, the whole process of working on a project together with members with different skills and backgrounds, was worthwhile enough to continue and eventually resulted in a Waterbuoy that has been floating around for two years.
The design was a yellow Lego head, a solar panel, a SodaqONE LoRa board and a temperature sensor in a PVC tube. The buoy transmitted its data (temperature, GPS location and battery voltage) over The Things Network LoRa to an InfluxDB server of Nescis (one of our members). The buoy had its own website showing realtime data, description of the project and a link to our github repository for the software developed.
Ideas to extend the set-up with more sensors (for conductivity, pH, dissolved oxygen and turbidity) were postponed when we found how quickly sensors became dirty from biofouling and how frequent these would need cleaning.
When we learned that e.coli bacteria are actually the most important thing to monitor (which currently can not be done with cheap sensors), Sensemakers started a new project to monitor sewer overflow.
Since another new project “Mijn Omgeving” had already started to do the same type of measurements as the buoy, the Lego waterbuoy was removed from the water when the hardware broke after two years.
Data is still available for who is interested.