The goal of my project is to measure the concentration of algae in water. For this I developed a buoy with a long pipe that only included one LED and one light sensor. After some testing, it turned out that the measurements were not accurate enough. After that, I developed a 3d-printed wreath of four three- colored- LEDs and one central camera in the middle. The LEDs can emit light in red, green or blue. The camera captures the reflected light from the water inside the cube. This system is controlled by a Raspberry Pi that analyzes the images.
All of the electronics are in a second waterproof-tube that is outside of the small tube. All connections are isolated to protect the electronics. At the top of the inside, there is a simple on/off switch, a 9V battery and a SD-Shield which saves the data. On this central shield there is also an emergency LED that starts to blink when the SD-Shield isn't working well. Furthermore there is a GSM- Module that is able to send and receive SMS in case of dangerous concentrations of algae that can endanger shipping or the ecosystem in the water. It also sends an SMS when the battery voltage is getting low and needs to be switched out.
This systems makes sure that the buoy is running all time.
Testing first started with shaken Sushi-Algae that we concentrated in different concentrations of Algae in the water and dirt to reproduce the North see as best as possible. This measurements gave us a scale which values belong to which concentration. Also we want to measure temperature and oil in the water.