Proposal for Low-Cost Optical Sensor for Measuring Flow Velocities in Aquatic Environments

Area of Science:

• Oceanography
• Marine Biology
• Environmental Science

Background:

• The ocean significantly influences marine life, habitats, and global climate.
• Issues like beach erosion, propagule survival (e.g., *Posidonia oceanica*), and nutrient distribution require effective monitoring tools.

Purpose of the Study:

• To introduce an innovative, cost-efficient sensor for quantifying hydrodynamic velocity.
• To validate the sensor's effectiveness and the accuracy of its processing algorithm for marine applications.

Main Methods:

• Utilized Light Emitting Diodes (LEDs) and Light Dependent Resistors (LDRs) to detect changes in light absorption and scattering.
• Measured output voltage to quantify hydrodynamic velocity.
• Simulated runoff conditions and tested sensor performance in freshwater and chlorophyll-containing water.

Main Results:

• The sensor demonstrated effectiveness and accuracy in measuring hydrodynamic velocity.
• The blue LED achieved a mean relative error of 7.59% in freshwater.
• The yellow LED showed a mean relative error of 6.80% in chlorophyll-containing water, with blue, green, and white LEDs showing similar velocities in runoff simulations.

Conclusions:

• The proposed sensor is a highly effective and accurate tool for measuring hydrodynamic velocity.
• Its significant cost-efficiency makes it an accessible solution for managing marine ecosystems sustainably.
• This technology can aid in addressing critical environmental challenges within marine habitats.