Sensor

KdUINO

Measure water transparency with a low-cost sensor that you can build! Advanced KdUINO sensors also detect optical and temperature stratification in the water column.

Developer: Institute of Marine Sciences - CSIC
Contact: Jaime Piera - jpiera@icm.csic.es

Specifications

Resolution: KdUINO measures K_d in the PAR, but also in the spectral zone of Red, Green and Blue.
The professional version of KdUINO measures temperature with precision ±0.5°C in the range between –10°C and +85°C.
Dimensions: Depends on the version of the KdUINO.
Power requirement: Depends on the version of the KdUINO, in general it uses LiPo batteries 800mAh.
Method to transmit data: Can save data internally to an SD card and then transmit data with Wifi or IoT technologies such as LoRa (using The Things Network) or Sigfox.
Deployment method: It is important to take measurements when the solar zenith angle is around [70-110]º (the sun is overhead), to avoid shadows. Whilst taking measurements, the KdUINO should be placed alone to prevent shadows.

Supporting materials

User guide: KduPRO - User guide and technical documentation
Video demonstration: Monitoring water quality through the KduPRO, a Do-It-Yourself instrument
Presentation: Evolution of KdUINO in MONOCLE

Overview

KdUINO is a moored instrument that measures the diffuse attenuation coefficient (K_d), used to assess water transparency.

Studies have shown that coastal areas and lakes change rapidly over space and time, especially when close to human activities and in areas strongly affected by rivers, wind and waves. Monitoring water transparency provides an indicator of the environmental status of the water body by providing information about phytoplankton concentrations or levels of dissolved organic and inorganic compounds.

The KdUINO is low cost and easy to deploy, it supports increased in situ monitoring capacity and helps to plug the gap of temporal coverage left by satellite data.
The simple structure of the KdUINO combined with the low-cost electronics makes this instrument suitable as a Do-It-Yourself (DIY) tool for citizen science-based water quality monitoring.
The system is also suitable for research laboratories and environmental monitoring companies which need cost-effective K_d estimations with high spatial and temporal resolution.

Through MONOCLE the KduSTICK, KduPRO and the KduMOD have been developed.

KduSTICK is a lightweight, easy to transport model. The light measurement sensors have been contained in a watertight transparent 1.5m tube, which is placed vertically in the water column and floats like a buoy.
KduPRO (prototype of the KduMOD) is a cost-effective and Do-It-Yourself moored instrument designed to obtain Kd measurements in the first meters of the water column. Each module contains a light sensor that allows measures in the spectral zone of PAR (Photosynthetically Active Radiation), red, green and blue, and can store data independently. The depth of each module can be modified according to the requirements of the project or the environment.
KduMOD is the modular version of the KdUINO. Each module contains light and temperature sensors that can store and transmit data independently. Thus, the KduMOD can be connected to other KduMODs to create an array of sensors options. The depth of each module can be modified according to the requirements of the project or the environment.

Diagram showing the various elements of KdUINO

What does it measure?

Diffuse attenuation coefficient (Kd)
Temperature (only KduMOD version)

How does it work?

To estimate Kd, the KdUINO measures the light intensity at several depths in the water column. Using the linear regression of a set of such measurements, Kd is retrieved applying the Beer-Lambert law on the light measurements.

The water temperature is measured with a sensor.