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Wireless sensor node for surface seawater density measurements.

Baronti F, Fantechi G, Roncella R, Saletti R - Sensors (Basel) (2012)

Bottom Line: The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller.Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network.The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Ingegneria dell'Informazione: Elettronica, Informatica, Telecomunicazioni, University of Pisa, Pisa, Italy. f.baronti@iet.unipi.it

ABSTRACT
An electronic meter to measure surface seawater density is presented. It is based on the measurement of the difference in displacements of a surface level probe and a weighted float, which according to Archimedes' law depends on the density of the water. The displacements are simultaneously measured using a high-accuracy magnetostrictive sensor, to which a custom electronic board provides a wireless connection and power supply so that it can become part of a wireless sensor network. The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller. Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network. The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings.

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Related in: MedlinePlus

Operating principle of the density meter. A spherical probe floats at the water surface, while a semi-floating probe is partly immersed. The immersion depends on the water density. The MS sensor accurately measures the displacement difference between the two probes, from which the density is calculated.
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f1-sensors-12-02954: Operating principle of the density meter. A spherical probe floats at the water surface, while a semi-floating probe is partly immersed. The immersion depends on the water density. The MS sensor accurately measures the displacement difference between the two probes, from which the density is calculated.

Mentions: Let us briefly recall the theory behind the functionality of the hydrometer and how it is used with this electronic instrument. Figure 1 shows the working principle of the density meter. The MS sensor has two magnet probes and its rod is immersed in the seawater. The first probe is located inside a sphere that floats at the sea surface. The second probe is inserted in another structure, the weight of which is chosen so that the structure is semi-floating below the first sphere. If we assume that the floating sphere immersion is constant with the water density, this probe gives a displacement measurement hs that corresponds to the surface level of the liquid. Instead, the second probe in the semi-floating structure is submerged more or less according to the water density. Therefore, its displacement hwf, as measured by the MS sensor, changes according to the liquid density. The difference between the two readings gives the exact immersion of the semi-floating structure and is thus related to the buoyancy force and the water density value.


Wireless sensor node for surface seawater density measurements.

Baronti F, Fantechi G, Roncella R, Saletti R - Sensors (Basel) (2012)

Operating principle of the density meter. A spherical probe floats at the water surface, while a semi-floating probe is partly immersed. The immersion depends on the water density. The MS sensor accurately measures the displacement difference between the two probes, from which the density is calculated.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376632&req=5

f1-sensors-12-02954: Operating principle of the density meter. A spherical probe floats at the water surface, while a semi-floating probe is partly immersed. The immersion depends on the water density. The MS sensor accurately measures the displacement difference between the two probes, from which the density is calculated.
Mentions: Let us briefly recall the theory behind the functionality of the hydrometer and how it is used with this electronic instrument. Figure 1 shows the working principle of the density meter. The MS sensor has two magnet probes and its rod is immersed in the seawater. The first probe is located inside a sphere that floats at the sea surface. The second probe is inserted in another structure, the weight of which is chosen so that the structure is semi-floating below the first sphere. If we assume that the floating sphere immersion is constant with the water density, this probe gives a displacement measurement hs that corresponds to the surface level of the liquid. Instead, the second probe in the semi-floating structure is submerged more or less according to the water density. Therefore, its displacement hwf, as measured by the MS sensor, changes according to the liquid density. The difference between the two readings gives the exact immersion of the semi-floating structure and is thus related to the buoyancy force and the water density value.

Bottom Line: The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller.Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network.The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Ingegneria dell'Informazione: Elettronica, Informatica, Telecomunicazioni, University of Pisa, Pisa, Italy. f.baronti@iet.unipi.it

ABSTRACT
An electronic meter to measure surface seawater density is presented. It is based on the measurement of the difference in displacements of a surface level probe and a weighted float, which according to Archimedes' law depends on the density of the water. The displacements are simultaneously measured using a high-accuracy magnetostrictive sensor, to which a custom electronic board provides a wireless connection and power supply so that it can become part of a wireless sensor network. The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller. Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network. The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings.

Show MeSH
Related in: MedlinePlus