Research Article Oceanographic Multisensor Buoy Based on Low...

Research ArticleOceanographic Multisensor Buoy Based on Low Cost Sensors forPosidonia Meadows Monitoring in Mediterranean Sea

Sandra Sendra Lorena Parra Jaime Lloret and Joseacute Miguel Jimeacutenez

Instituto de Investigacion para la Gestion Integrada de Zonas Costeras Universidad Politecnica de ValenciaGrao de Gandia 46730 Valencia Spain

Correspondence should be addressed to Lorena Parra loparboupvnetupves

Received 10 December 2014 Accepted 16 June 2015

Academic Editor Fanli Meng

Copyright copy 2015 Sandra Sendra et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

There are some underwater areas with high ecological interest that should be monitored Posidonia and seagrasses exertconsiderable work in protecting the coastline from erosion In these areas many animals and organisms live and find the grasslandfood and the protection against predators It is considered a bioindicator of the quality of coastal marine waters It is important tomonitor them and maintain these ecological communities as clean as possible In this paper we present an oceanographic buoyfor Posidonia meadows monitoring It is based on a set of low cost sensors which are able to collect data from water such assalinity temperature and turbidity and from the weather as temperature relative humidity and rainfall among othersThe systemis mounted in a buoy which keeps it isolated to possible oxidation problems Data gathered are processed using a microcontrollerFinally the buoy is connected with a base station placed on the mainland through a wireless connection using a FlyPort moduleThe network performance is checked in order to ensure that no delays will be generated on the data transmission This proposalcould be used to monitor other areas with special ecological interest and for monitoring and supervising aquaculture activities

1 Introduction

Wireless Sensor Networks (WSNs) research works have inc-reased hugely in recent years due to the many types ofapplications [1 2] WSNs are composed of sensors that sensedata from the environment and nodes that receive the senseddata and process them Due to their lowmemory and limitedbattery [3] nodes cannot store a lot of data so they mustsend it AsWSNs can be composed of hundreds of nodes theyneed to self-organize based ondifferent network architecturesand use protocols to communicate These protocols shouldhave into consideration several aspects such as the energyconstrains [4] security in data transmission and beingtolerant to network failures [5] in order to maintain a correctnetwork performance

Sensor nodes aremainly composed of 4 differentmodules[6] First the sensingmodule which performs the data acqui-sition can be composed of one or more sensors that senseone or more environmental parameters and the sensingprocessing module The central processing unit performs theprocessing and storage operations with the received data

The wireless transceiver module is in charge of the wirelesscommunications and can use different wireless technologyas radio frequency WiFi and ZigBee Finally the powersupplymodule which should provide a continuous and stablepower to the rest of modules is composed of batteries and apower management system It is recommended to have someenergy harvesting system and implement some energy savingstrategies [7]

Even that the majority of WSNs are developed for terres-trial applications the marine applications are becoming animportant area 34 of our planet is covered by water Thehuman impact in oceans is becomingmore andmore evidentThe need of continuous monitoring of underwater environ-ments can be covered by using WSNs Terrestrial and under-water WSNs have some differences The environment inunderwater WSNs is more aggressive than in terrestrialWSNs so the deployed devices will require major protectionwater isolation to avoid corrosion and biofouling Because thewaves from tidals and ships can produce movements in theWSNs the system must be prepared to assume these move-ments and changes of locations from its initial deployment

Hindawi Publishing CorporationJournal of SensorsVolume 2015 Article ID 920168 23 pageshttpdxdoiorg1011552015920168

2 Journal of Sensors

Table 1 Important parameters for underwater WSNs

Node position Parameters measured in underwater environments by WSNsSurface Water column Sea bed

Important parameters

Swell height Temperature TemperatureSwell direction Pressure Pressure

Hydrocarbons ppm Dissolved oxygen Dissolved oxygenAir temperature Salinity (or conductivity) Redox potentialAir pressure mb Turbidity pHWind speed Chlorophyll Hydrogen sulfide

Wind direction Phosphate VibrationsPrecipitation Nitrate Movement

Atmospheric pressure pHRelative humidity Blue-green algae

RH solar radiation AmmoniumammoniaSurface salinity (or conductivity) Chloride

RhodamineDissolved organic carbon

Dissolver metals

Generally underwater WSNs are used to cover higher areasthan terrestrial WSNs [8] the energy consumption will behigher and the signals are attenuated in the underwater envi-ronments So it is important to implement energy-efficienttechniques in data processing [9 10] and energy harvestingsolutions [11] to prolong the network lifetime [12] and net-work stabilityThe price of devices used in underwaterWSNsis usually higher than in terrestrialWSNs In addition sensornodes in underwater WSNs are placed in a specific placealong the water column so flotation andmooring devices areneeded [13] Finally the wireless communication technologyin terrestrial WSNs use different radio frequencies howeverin underwater WSNs the water produces an important atten-uation on radio frequencies so there are many deploymentsusing other technologies such as sound or light [14]

Underwater sensors can be placed at the bottom at thesurface or at different points along the water column Thesensed parameters can change depending on the point wherethe sensors are placed and the objective of the WSN Forexample in environments without light there is no need tomeasure chlorophyll and in environments far from humanimpact there is no need to measure the presence of hydrocar-bons Table 1 shows the main parameters that can be sensedas a function of the place where sensor nodes are placed in thewater column Although there is a large list of parameters themost common ones are temperature (119879) pH turbidity anddissolved oxygen (DO) [13]

According to [15] underwater WSNs are mainly appliedto general ocean sensing andmonitoring water quality mon-itoring fish farms monitoring coral reef monitoring andmarine shellfish monitoring (see Figure 1) However the the-oretical applications are wider [16 17] We can highlight theocean sampling networks environmental monitoring disas-ter prevention assisted navigationmine reconnaissancemil-itary purposes or undersea explorations but there are veryfew works published showing real deployments Combining

General ocean sensing andmonitoring

(5000)Water quality monitoring

(3182)

Fish farm monitoring

(908)

Coral reef monitoring

(455)

Marine shellfish

monitoring(455)

Figure 1 Main applications of underwater WSNs

some of these parameters we can find several important app-lications which could help us to protect sensitive areas suchas seagrasses and Posidonia meadows

Seagrasses meadows are considered an important ecosys-tem because they are composed of plants that lived in under-water environments Since 1980 there has been a decrease of29 of the colonized areas due to several threats The lossrate is 110 km2year [18]Themost important parameters thatrestrict the potential area for seagrasses are light exposure(10 of surface radiation) physical exposure (maximumcurrent 15ms) substratum (gravel sand or mud) temper-ature (minus1∘C in winter to 30∘C in summer) and salinity (5 to45 PSU) These data correspond to the species which presentthe most restrictive needs The most affected environment isthe coastal area which plays an important role

The main functions of these ecosystems are

(i) sediment and nutrient retention [19]

(ii) nursery for juvenile fish [19]

Journal of Sensors 3

(iii) food for species such as manatee dugong and greenturtle [18]

(iv) some epiphyte algae living over the seagrass increas-ing the productivity [19]

(v) CO2retention (even more important than in tropical

rain forest) [20]Some threats are [19](i) increase of turbidity(ii) increase of temperature (due the global warming)(iii) salinity changes(iv) foreigner species(v) dredging actions to import sand to the beaches(vi) massive grazing eventsThe increase of temperature is producing a loss of seagrass

community and due to that reduction the amount of CO2

that the meadows can retain decreases Because of these thefree CO

2in the atmosphere increases and so its temperature

increases This process forms a negative feedback loop Thetemperature is a very important parameter that should bemonitored in detail to see the changes in the seagrass mead-ows and the rest of flora and fauna [21]

Our system allows evaluating the role of different threatsin the reduction of seagrass meadows We can estimate theeffect of salinity turbidity and temperature changes togetherand separately In addition with the meteorological informa-tion it is possible to estimate the physical exposure and thesolar radiation Moreover a fuel detection system is includedto evaluate the effect of this specific pollutant Systems likethese ones are used to monitor other underwater environ-ments and threats like seagrasses In [22] authors use a sys-tem to monitor coral reefs in Australia

According to [13] underwater WSNs are mainly devel-oped in Europe (26 references) North America (19 refer-ences) China (21 references) and Australia (12 references)The main topologies used for this purpose are star topologyand topologies partially connected [13]There are a huge vari-ety of protocols specifics for underwater environments suchas VBFHH-VBF and FBR Each one of themhas benefits anddrawbacks It has no sense to select one of them as a functionof our scenarios [23]

The main challenges for underwater WSNs are [14 22](i) sensors protection to avoid corrosion and biofouling

and ensure the isolation from the water(ii) advanced buoy design with low cost waterproof and

strong stability it should also have an energy harvest-ing system and a mooring system

(iii) energy harvesting system design there are severalrenewable power sources that can be used in the oceanlike seawater generator tidal power or wind energy

(iv) system stability and reliability(v) distributed localization and time synchronization

Continuous changes in sensors can affect the preci-sion of location and the time of data is crucial for goodanalysis

In this paper we are going to present the design ofan oceanographic multisensor buoy for Posidonia meadowsmonitoring in theMediterranean SeaThe system is based on2 sets of low cost sensors that are able to collect data from thewater such as salinity temperature or turbidity and from theweather such as temperature relative humidity or rainfallamong others The system is held in a buoy which maintainsthe system isolated from the water to avoid possible problemsof oxidation The data gathered by all sensors are processedusing a microcontroller Finally the buoy is connected withthe base station through awireless connection using a FlyPortmodule The whole system and the individual sensors havebeen tested in a controlled environmentThis proposal couldbe used tomonitor other areas with special ecological interestand for monitoring and supervising several aquaculture acti-vities

The rest of this paper is structured as follows Section 2shows some previous woks related to multiparametric sys-tems used for monitoring some natural environmentsSection 3 explains the main parts of our system as well asthe wireless module used for connecting the buoy with themainland The design and operation of the sensors usedto measure the marine parameters are shown in Section 4meanwhile the design and operation of the sensors used tomeasure meteorological parameters are shown in Section 5The network architecture protocol to establish the connec-tion and the network performance are shown in Section 6Finally Section 7 shows the conclusion and future work

2 Related Work

In this section we present a selection of papers where dif-ferent sensors are used for monitoring aquatic environmentsMany of them propose the water monitoring to obtain real-time information about parameters such as quality and com-ponent analysis Among these we find the following ones

OrsquoFlynn et al [24] described the operation of ldquoSmart-Coastrdquo a multisensor system for water quality monitoringThe system is aimed at providing a platform capable of meet-ing the monitoring requirements of the Water FrameworkDirective (WFD) The key parameters under investigationinclude temperature phosphate dissolved oxygen conduc-tivity pH turbidity and water level Authors also presenteda WSN platform developed at Tyndall with ldquoPlug and Playrdquocapabilities which allows the sensor integration as well as thecustom sensors under development within the project Theirresults indicated that a low power wireless multisensor net-work implementation is viable

Kroger et al [25] stated that biosensors have great poten-tial in the marine environment The development of biosen-sors for taking measurements in situ is a difficult challengeand that work is underway to address some of the issuesraisedWhile the ability tomake such observations is the ulti-mate goal of most developments the ability to make decen-tralized measurements in the field rather than having toprocess collected samples in specialized laboratories is a sig-nificant advance which should not be overlooked This is anarea where biosensors are likely to find their initial significant


applications the low cost user-friendly test that can be car-ried out to prescreen samples possibly helping to focus thesample collection effort for further detailed chemical analysis

Thiemann and Kaufmann [26] present algorithms for thequantification of the trophic parameters the Secchi disk tran-sparency and a method to measure the chlorophyll concen-tration based on the hyperspectral airborne data The algo-rithms were developed using in situ reflectance data Thesemethods were validated by independent in situ measure-ments resulting in mean standard errors of 10ndash15m for Sec-chi disk transparency and of 10-11mgL for chlorophyll regar-ding the case of HyMap sensors The multitemporal appli-cability of the algorithms was demonstrated based on a 3-year database With the complementary accuracy of Secchidisk transparency and chlorophyll concentration and theadditional spatial and synchronous overview of numerouscontiguous lakes this remote sensing approach gives a goodoverview of changes that can then be recordedmore preciselyby more extensive in situ measurements

Thewater qualitymonitoring at a river basin level tomeetthe requirements of the Water Framework Directive (WFD)poses a significant financial burden using conventional sam-pling and laboratory tests based on techniques presented byOrsquoFlynn et al [27] They presented the development of theDEPLOY project The key advantages of using WSNs are thefollowing ones

(i) higher temporal resolution of data than the onesprovided by traditional methods

(ii) data streams frommultiple sensor types in amultista-tion network

(iii) data fusion from different stations could help toachieve a better understanding of the catchment aswell as the value of real-time data for event monitor-ing and catchment behavior analysis

Data from monitoring stations can be analyzed andtransmitted to a remote officelaboratory using wireless tech-nology in order to be statistically processed and interpretedby an expert in this kind of systems Rising trends for anyconstituent of interest or breaches of Environmental Qual-ity Standards (EQS) will alert relevant personnel who canintercept serious pollution incidents by evaluating changes inwater quality parameters To detect these changes it is nec-essary to perform measurements several times per day Thecapabilities of DEPLOY system for continuously taking sam-ples and communicating them allow reducing monitoringcosts while providing better coverage of long-term trends anddetecting fluctuations in parameters of interest

Guttler et al [28] present new results for the character-ization of the Danube Delta waters and explore multisensorturbidity algorithms that can be easily adapted to this pur-pose In order to study the turbidity patterns of DanubeDelta waters optical remote sensing techniques were used tocapture satellite images of more than 80media with high spa-tial resolution

In [29] Albaladejo et al explain and illustrate the designand implementation of a new multisensor monitoring buoy

system The sensor buoy system offers a real opportunityto monitor coastal shallow-water environments The systemdesign is based on a set of fundamental requirements Themain ones are the low cost of implementation the possibilityof applying it in coastal shallow-water marine environmentssuitable dimensions to be deployed with very low impact overthe medium the stability of the sensor system in a shiftingenvironment like the sea bed and the total autonomy ofpower supply and data recording Authors have shown thatthe design cost and its implementation are inexpensive Thisimplies that it can be integrated in a WSN and due to theproprieties of these systems they will remain stable in aggres-sive and dynamic environments like the sea Authors haveidentified the basic requirements of the development processof the electronic and mechanical components necessary toassembly a sensor

Jianxin et al [30] proposed a new method to measuremarine parameters ofmarine power systemsThe system per-forms a synchronous sampling and distributed data fusionwhich is based on the optimal state estimation The single-sensor measuring data is accurately estimated by the Kalmanfilter and the multisensor data behavior is globally estimatedas a combination of these dataThe simulation test shows thatthemeasured parameters obtained with themethod based onmultisensor data fusion present more accuracy and stabilitythan the results obtained by the direct measurement methodwith single-sensor

Vespe et al [31] presented an overview of the Satellite-Extended-Vessel Traffic Service (SEV) system for in situ andEarth Observation (EO) data association The descriptionof the cognitive data correlation concept shows the benefitsbrought to the resulting RecognizedMaritime Picture (RMP)in supporting decisionmaking and situation awareness appli-cationsThey show the results of multitechnology integrationand its benefits brought in terms of suspect vessel detectionand propagation trackingThe navigational and geographicalknowledge is exploited for the final data association imple-mentationThe vessel motion features and the scenario influ-ence are used to estimate the degree of correlation confidenceThe tactical scenario depiction has also shown the improve-ment in maritime traffic for coastal and open waters surveil-lance

Sousa-Lima et al [32] presented an inventory list of fixedautonomous acoustic recording (AR) devices including acr-onyms developers sources of information and a summaryof the main capabilities and specifications of each AR systemThe devices greatly vary in capabilities and costs There aresmall and hand-deployable units for detecting dolphin andporpoise clicks in shallow water and larger units that can bedeployed in deep water to record at high-frequency band-widths for over a year but they must be deployed from alarge vessel The capabilities and limitations of the systemsreviewed are discussed in terms of their effectiveness inmon-itoring and studying marine mammals

Some more interesting research works can be found in[33] but no one has the same features and purpose than theone proposed in this paper


3 Proposal Description

The main aim of this paper is to develop a multisensor buoyable to collect meteorological and marine parameters andsend them to a base station placed in themarine port ormain-land This section explains the main parts of our multisensorbuoy as well as the wireless node used to implement ournetwork and where the sensors will be placed in the buoy

31 Multisensor Buoy The buoy consists of a plastic part orfloat which provides sufficient buoyancy to the whole systemand a fiber structure which will be in charge of containingall electrical and electronic components and the battery (seeFigure 2) The interior of this structure is easily accessiblethrough a small door in its exterior side

Moreover the float (see Figure 3) has a longitudinal open-ing that traverses the entire object Within this opening thesensors are placed in nonmetallic structures The sensors arealways submerged in thewater because the buoyancy capacityplaces the sensors under the waterline above the sensorsThere is an opening to allow the water flow and its exchangewithout problems and to avoid the stagnant water The mainreason for locating sensors in this part is to keep them pro-tected against shock and other problems

Ourmultisensor system comprises two groups of sensorsThe first one is responsible for collecting meteorologicalparameters such as rainfall temperature relative humidityand solar radiation The second group of sensors is locatedunder the water and they collect data about water conditionsIn our case the system takes measurements of temperaturesalinity turbidity and presence of fuel

All sensors are connected to a processor capable of cap-turing analog signals from our sensors process them andwirelessly send these data to the base station located at themainland

32 Design of Wireless Node Our wireless node is based onthe wireless module called Openpicus FlyPort [34] Thiswireless module is composed by the Certified TransceiverWiFi IEEE 80211 MicrochipMRF24WB0MA and although ituses the IEEE 80211 wireless technology this device presentsone of the smallest energy consumptionsThemain feature ofthis device is its 16-bit low power microcontroller ProcessorMicrochip PIC24FJ256 with 256K Flash 16 K Ram and16Mips 32MHz Figure 4 shows a view of the top side ofthis module

There are several reasons to use this wireless moduleThemain advantage over existing systems is that it works underthe IEEE 80211 standard which makes fairly inexpensive thepurchase of these devices In addition it is programmed in Clanguage which permits great versatility in the developmentof new applications In addition it offers an embedded web-site that can be used to see the current values gathered by thesensors Finally its small size makes this device ideal for sev-eral applications such as environmental and rural monitoring[35] agriculture [36 37] animal monitoring [38] indoormonitoring [39] orwearable sensors for e-health applications[40 41] among others

Solar panels

BuoyMeteorologic sensors

Figure 2 Multisensor buoy

Finally because our multisensor buoy is working with 9different sensors (8 sensors with an analog value as responseand a sensor with an ONOFF response) we need a micro-controller with at least 8 analog inputs The digital inputcan be controlled using the FlyPort module In our case thedevice used is 40-Pin Enhanced Flash Microcontrollers with10-bit AD and nanoWatt Technology (PIC18F4520 byMicro-chip) One of the main characteristics of this device is its 10-bit Analog-to-Digital Converter module (AD) with up to 13channels which is able to perform the autoacquisition and thedata conversion during the sleepmodeMicrochip claims thatpic18f4520s ADC can go as high as 100K samples per secondalthough our application does not require this sampling rate

Figure 5 shows a diagram with the connection betweensensors the microcontroller and the base station located atthe mainland or marine port

4 Sensors for Marine Parameters Monitoring

In this section we are going to present the design and oper-ation of sensors used to measure marine parameters Foreach sensor we show the electric scheme and mathematicalexpressions which relate the environmental parameter mag-nitudes and electrical values For our new developments wewill also show the calibration process

41 Water Temperature Sensor In order to develop the watertemperature sensor it is used an NTC resistance (NegativeTemperature Coefficient) (see Figure 6) that is as the tem-perature increases the carrier concentration and the NTCresistance will decrease its magnitude

The way to connect this sensor to our circuit is forminga voltage divider and the output of this circuit is connectedto an analog input of our wireless node Our NTC is placed


Float of buoy

Water

Nonmetallic structures

Opening that

Oceanographic sensors

of water by the sensorsallows the passage

to support

Figure 3 Float of buoy with the sensors

Figure 4 FlyPort module

in the lower part of the voltage divider This protects oursystem When the current flowing through the NTC is lowwe have no problem because heat dissipation is negligible(119881 sdot 1198682) However if heat dissipation increases this can affectthe resistive value of the sensor For this reason the NTCresponse is not linear but hyperbolic But the configuration ofa voltage dividerwillmake the voltage variation of119881out almostlinear

Regarding the other resistance that forms the voltagedivider it is used as resistance of 1 kΩ This fact will allowleveraging the sampling range with a limited power con-sumption given by the FlyPort The schematic of the elec-tronic circuit is shown in Figure 7

The output voltage as a function of the temperature (in K)can be modeled by

119881out (119905) = 119881cc1198770 sdot 119890119861(1119905minus11199050)

1198770 sdot 119890119861(1119905minus11199050) + 119877sup

(1)

where 119877sup is the superior resistance of the voltage dividerformed by this resistance and the NTC 119877

0is the value of the

NTC resistance at a temperature 1199050which is 298K and 119861 is

the characteristic temperature of amaterial which is between2000K and 5000K

We can calculate the temperature in ∘C by

119905 (∘C)

=1199050

1199050 sdot ((ln ((1198771 sdot 119881119877NTC) (1198770 sdot (119881out minus 119881119877NTC)))) 119861) + 1

minus 273

(2)

where 119881119877NTC

is the voltage registered on the NTC resistor 1198770

is the value of NTC resistance at a temperature 1199050which is

298K and 119861 is the characteristic temperature of a material119881out is the output voltage as a function of the registered tem-perature Finally 119905 (∘C) is the water temperature

To gather the data from the sensor we need a short pro-gram code in charge of obtaining the equivalence betweenvoltage and temperature Algorithm 1 shows the program-ming code used

Finally the sensor is tested for different temperaturesFigure 8 shows the temperaturemeasured as a function of theoutput voltage

42 Water Salinity Sensor The low cost salinity sensor isbased on a transducer without ferromagnetic core [42 43]The transducer is composed of two coils one toroid and onesolenoid (placed over the toroid)The characteristics of thesecoils are shown in Table 2 Figure 9 shows the salinity sensor

In order to measure water salinity we need to power oneof these coils (the one with fewer spires) with a sinusoidal sig-nal The amount of solute salts in the water solution affectsand modifies the magnetic field generated by the poweredcoil The output voltage induced by the magnetic field in thesecond coil is correlated with the amount of solute salts


Temperature

Rain

Wind

Solar radiation

Relative humidity

Fuel detection

Water temperature

Turbidity

Salinity

Solar panel

Battery

Regulator

DC converter

Serial communication

Meteorological measurements Underwater measurements

Power supply system

InternetRemoteaccess

Server

Mainland

WiFi

Figure 5 Diagram with all connections and the proposed architecture

Figure 6 NTC for the water temperature sensor

We use this system instead of commercial sensors becauseour system is cheaper than commercial devices Anotheradvantage of our system is that it does not require periodiccalibrations and it is easy to isolate from water

It is important to know the frequency where our systemdistinguishes different salinity levels withmore precision thisfrequency is called working frequency In order to find thisworking frequency we developed several tests using sinuso-idal signal at different frequencies to power the first coilTests are performed using 5 samples with different salinityThe samples were composed from tap water and salt Theirsalinities go to tapwater up towater highly saturatedwith saltThe conductivity values typical for sea water and freshwaterare included in the samples To find theworking frequency allsamples are measured at different frequencies Eight differentfrequencies are tested the frequencies go from 10 kHz to750 kHz The results of these tests are shown in Figure 10

Vcc = 5V

R1 = 1kΩ

minusT

To microprocessor

RNTC = 10kΩ

Figure 7 Electronic circuit of the water temperature sensor

It represents the maximum amplitude registered for eachsample at different frequenciesThe input signal for the powe-red coil is performed by a function generator [18] Tomeasurethe output voltage in the first tests we use an oscilloscopeFigure 11 shows the oscilloscope screen where we can see theinput and output sinusoidal waves We can see that 150 kHz


while(1)myADCValue = ADCVal(1)myADCValue = (myADCValue lowast 2048)1024sprintf(buf ldquodrdquo myADCValue)vTaskDelay(100)

Algorithm 1 Programming code to read the analog input fromwater temperature sensor

05

1015202530354045

42 43 44 45 46 47 48Output voltage (V)

Tem

pera

ture

(∘C)

Figure 8 Temperature measured versus output voltage

Table 2 Coils features

Coils featuresToroid Solenoid

Wire Diam 08mm 08mm

Size and core

Inner coil diameter232mm

Outer coil diameter565mm

Coil high 269mmCore nonferrous




Number of spires 81 in one layer 324 in 9 layers

is the frequency where it is possible to clearly distinguishbetween different samples At 590 kHz it is possible to distin-guish between all the samples except for 17 and 33 ppm Theonly frequency that our sensor is able to distinguish betweenall samples is 150 kHz This frequency is selected as workingfrequency

The main function of the FlyPort is the generation of thesinewave used to power our transducer and the acquisition ofthe resulting signalThe sensor node generates a PWM signalfrom which we obtain a sinusoidal signal used to power thetransducer The PWM signal needs to be filtered by a bandpass filter (BPF) in order to obtain the sinusoidal signal aswe know it Once PWM signal is generated by the microcon-troller it is necessary to filter this signal by a BPF with thecenter frequency at 150 kHz in order to obtain the desired sinewave Figure 13 shows a PWM signal (as a train of pulses withdifferent widths) and the sine wave obtained after filtering thePWM signal

Figure 9 Salinity sensor

005

115

225

335

445

0 5 10 15 20 25 30 35 40 45

Out

put v

olta

ge (V

)

Salinity (ppm)

10kHz

150kHz

250kHz500kHz

590kHz

625kHz375kHz750kHz

Figure 10 Output voltage of the salinity sensor as a function of thefrequency

Induced signal

Input signal

Figure 11 Oscilloscope during the tests


0

05

1

0

10

026

40

528

079

21

056

132

158

41

848

211

22

376

264

290

43

168

343

23

696

396

422

44

488

475

25

016

528

554

45

808

607

26

336

66

686

47

128

739

27

656

792

818

48

448

871

28

976

924

950

49

768

100

3210

296

105

610

824

110

8811

352

116

16

Am

plitu

de si

ne w

ave

Am

p litu

de P

WM

Time (120583s)

Figure 12 PWM signal and the resulting sine wave

Voutput

R1 R2

R3

R4C1

C2

C3 C4

Low pass filter with fc = 160kHz High pass filter with fc = 140kHzR1 = 165kΩR2 = 154kΩ

R3 = 68kΩR4 = 18kΩ

C1 = 100pFC2 = 39pF

C1 = 100pFC2 = 100pF

Q = 081348921682Q = 0800164622228

10kΩ10120583F

Output voltageto FlyPort

PWM fromFlyPort +

minus

+minus

Figure 13 Electronic design of the low cost salinity sensor

The BPF is performed by two active Sallen-Key filters ofsecond order configured in cascade that is a low pass filter(LPF) and a high-pass filter (HPF)The cutoff frequencies are160 kHz and 140 kHz respectively (see Figure 12) PWM isgenerated by the wireless module The system is configuredto work at 150 kHz After that the system generates avariable width pulse which is repeated with a frequency of150 kHz Figure 14 shows the frequency response of our BPFAlgorithm 2 shows the program code for PWM signal gener-ation

In order to gather the data from the salinity sensor wehave programmed a small code The main part of this codeis shown in Algorithm 3 As it is shown the system will takemeasurements from analog input 1

Once we know that the working frequency is 150 kHzwe perform a calibration The calibration is carried out forobtaining the mathematical model that relates the outputvoltage with the water salinity The test bench is performedby using more than 30 different samples which salinities gofrom 019 ppm to 38 ppmThe results of calibration are shownin Figure 15

We can see that the results can be adjusted by 3 linealranges with different mathematical equations Depending onthe salinity the sensor will use one of these equations Equa-tion (3) is for salinity values from 0 ppm to 328 ppm and

Bode diagram

Mag

nitu

de (d

B)

40

0

minus40

minus80

minus120

minus160100E0 100E31E3 10E3 1E3 10E6

100E0 100E31E3 10E3 1E3 10E6

Phas

e (de

g)

180

120

60

0

Frequency (Hz)

Frequency (Hz)

Figure 14 Frequency response of our BPF

(4) is for values from 328 ppm to 113 ppm Finally (5) is forsalinities from 113 ppm to 35 ppm All these equations have aminimum correlation of 09751


include ldquotaskFlyporthrdquovoid FlyportTask()const int maxVal = 100const int minVal = 1float Value = (float) maxValPWMInit(1 1500000 maxVal)PWMOn(p9 1)While (1)for (Value = maxVal Value gtminVal Value minusminus)

PWMDuty(Value 1)vTaskDelay(1)

for (Value = minVal Value ltmaxVal Value + +)PWMDuty(Value 1)vTaskDelay(1)

Algorithm 2 Programming code for the PWM signal generation


Algorithm 3 Programming code to read the analog input of thesalinity sensor

Finally Figure 16 compares the measured salinity and thepredicted salinity and we can see that the accuracy of oursystem is fairly good

119881out 1 = 11788 sdot 119878 + 06037 1198772= 09751 (3)

119881out 2 = 02387 sdot 119878 + 33457 1198772= 09813 (4)

119881out 3 = 00625 sdot 119878 + 523 1198772= 09872 (5)

43 Water Turbidity Sensor The turbidity sensor is based onan infrared LED (TSU5400 manufactured by Tsunamimstar)as a source of light emission and a photodiode as a detector(S186P by Vishay Semiconductors) These elements are dis-posed at 4 cm with an angle of 180∘ so that the photodiodecan capture the maximum infrared light from the LED [44]

The infrared LED uses GaAs technology manufacturedin a blue-gray tinted plastic package registering the biggestpeak wavelength at 950 nm The photodiode is an IR filterspectrally matched to GaAs or GaAs on GaAlAs IR emitters(ge900 nm) S186P is covered by a plastic case with IR filter(950mm) and it is suitable for near infrared radiation Thetransmitter circuit is powered by a voltage of 5V while thephotodiode needs to be fed by a voltage of 15 V To achievethese values we use two voltage regulators of LM78XX series

012345678

0 5 10 15 20 25 30 35 40

Out

put v

olta

ge (V

)

Salinity (ppm)

Figure 15 Water salinity as a function of the output voltage

05

101520253035404550

0 5 10 15 20 25 30 35 40 45 50

Pred

icte

d sa

linity

(ppm

)

Measured salinity (ppm)

Figure 16 Comparison between our measures and the predictedmeasures

with permits of a maximum output current of 1 A TheLM7805 is used by the transmitter circuit and the LM7815 isused by the receiver circuit Figure 17 shows the electronicscheme of our turbidity sensor

In order to calibrate the turbidity sensor we used 8 sam-ples with different turbidity All of themwere prepared specif-ically for the experiment at that moment To know the realturbidity of the samples we used a commercial turbidimeterTurbidimeter Hach 2100N which worked using the samemethod as that of our sensor (with the detector placed at90 degrees) The samples were composed by sea water and asediments (clay and silt) finematerial that can bemaintainedin suspension for the measure time span without precipitateThe water used to prepare the samples was taken from theMediterranean Sea (Spain) Its salinity was 385 PSU Its pHwas 807 and its temperature was 211∘C when we were per-forming themeasuresThe 8 samples have different quantitiesof clay and silt The turbidity is measured with the com-mercial turbidimeter The samples are introduced in specificrecipients for theirmeasurementwith the turbidimeterTheserecipients are glass recipients with a capacity of 30mL Theamount of sediments and the turbidity of each sample areshown in Table 3 Once the turbidity of each sample is knownwe measured them using our developed system to test it Foreach sample an output voltage proportional to each mea-sured turbidity value is obtained Relating to the obtained


R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω

Figure 17 Schematic of the turbidity sensor

Table 3 Concentration and turbidity of the samples

Sample number Concentration of clay andsilt (mgL) Turbidity (NTU)

1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385

voltage with the turbidity of each sample the calibrationprocess is finished and the turbidity sensor is ready to be usedThe calibration results are shown in Figure 18 It relates thegathered output voltage for each turbidity value Equation (6)correlates the turbidity with the output voltage We also pre-sent the mathematical equation that correlates the outputvoltage with the amount of sediment (mgL) (see (7)) Finallyit is important to say that based on our experiments theaccuracy of our system is 015NTU

Output voltage (V) = 5196minus 00068

sdotTurbidity (NTU)(6)


sdotConcentration (mgL) (7)

Once the calibration is done a verification process iscarried out In this process 4 samples are used The samplesare prepared in the laboratory without knowing neither theconcentration of the sediments nor their turbidity

These samples are measured with the turbidity sensorThe output voltage of each one is correlated with a turbidity

3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)

Figure 18 Calibration results of the turbidity sensor

Table 4 Results verifying the samples

Sample Output voltage (V) Turbidity (NTU)1 467 77362 482 55293 48 58244 433 12736

measure using (6)Theoutput voltage and the turbidity valuesare shown in Table 4

After measuring the samples with the turbidity sensorthe samples are measured with the commercial turbidimeterin order to compare them This comparison is shown inFigure 19We can see the obtained data over a thin line whichshows the perfect adjustment (when both measures are thesame) It is possible to see that the data are very close exceptone case (sample 1) The average relative error of all samplesis 325 while the maximum relative error is 95 Thismaximumrelative error is too high in comparison to the errorof other samples this makes us think that there was amistake


0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)

Turbidity measured in Hach 2100N (NTU)

Figure 19 Comparison of measures in both pieces of equipment

in the sample manipulation If we delete this data the averagerelative error of our turbidity sensor is 117

44 Hydrocarbon Detector Sensor The system used to detectthe presence of hydrocarbon is composed by an optical cir-cuit which is composed by a light source (LED) and a recep-tor (photodiode) The 119881out signal increases or decreases dep-ending on the presence or absence of fuel in the seawater sur-face (see Figure 20) In order to choose the best light to imple-ment in our sensor we used 6 different light colors (whitered orange green blue and violet) as a light source For allcases we used the photoreceptor (S186P) as light receptor It ischeaper than others photodiodes but its optimal wavelengthis the infrared light Although the light received by the pho-todiode is not infrared light this photodiode is able to senselights with other wavelengths Both circuits are poweredat 5VAdiagramof the principle of operation of the hydrocar-bon detector sensor is shown in Figure 21

Finally the sensor is tested in different conditions Thesamples used in these tests are composed by seawater and fuelwhich is gasoline of 95 octanes They are prepared in smallplastic containers of 30mL with different amount of fuel (02 4 6 8 and 10mL) so each sample has a layer of differentthickness of fuel over the seawater The photodiode and theLED are placed near the water surface at 1 cm as we can seein Figure 22 where orange light is tested

The output voltages for each sample as a function of thelight source are shown in Figure 23 Each light has differentbehaviors and different interactions with the surfaces andonly some of them are able to distinguish between the pres-ence and absence of fuel The lights which present biggerdifference between voltage in presence of fuel and withoutit are white orange and violet lights However any light iscapable of giving us quantitative resultsThe tests are repeated10 times for the selected lights in order to check the stabilityof the measurements and the validity or our sensor Becauseour system only brings qualitative results that is betweenpresence and absence of fuel we only use two samples with

Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort

Figure 20 Sensor for hydrocarbon detection

different amounts of fuel (0 and 2mL)The results are shownin Figure 24 Table 5 summarizes these results

The results show that these three lights allow detecting thepresence of fuel over the water Nevertheless the white light isthe one which presents the lowest difference in mV betweenboth samples So the orange or violet lights are the best optionto detect the presence of hydrocarbons over seawater

5 Sensors for Weather Parameters Monitoring

This section presents the design and operation of the sensorsused tomeasure themeteorological parameters For each sen-sor we will see the electric scheme and themathematical exp-ressions relating the environmental parameter magnitudeswith the electrical values We have used commercial circuitintegrates that require few additional types of circuitry

51 Sensor for Environmental Temperature The TC1047 is ahigh precision temperature sensor which presents a linearvoltage output proportional to the measured temperatureThe main reason to select this component is its easy connec-tion and its accuracy TC1047 can be feed by a supply voltagebetween 27 V and 44V The output voltage range for thesedevices is typically 100mV at minus40∘C and 175V at 125∘C


Seawater

Fuel

Source of light Photodetector

Light emittedLight measured

Figure 21 Principle of operation of the hydrocarbon detector sen-sor

Figure 22 Test bench with orange light

This sensor does not need any additional design Whenthe sensor is fed the output voltage can be directly connectedto our microprocessor (see Figure 25) Although the operat-ing range of this sensor is between minus40∘C and 125∘C our use-ful operating range is from minus10∘C to 50∘C because this rangeis even broader than the worst case in the Mediterraneanzone Figure 26 shows the relationship between the outputvoltage and the measured temperature and the mathematicalexpression used to model our output signal

Algorithm 4 shows the program code to read the analoginput for ambient temperature sensor

Finally we have tested the behavior of this system Thetest bench has been performed during 2 months Figure 27shows the results obtained about the maximum minimum

0

2mL4mL

6mL8mL10mL

02468

101214161820

Violet Blue Green Orange Red White

Out

put v

olta

ge (m

V)

Light colour

Figure 23 Output voltage for the six lights used in this test

and average temperature values of each day Figure 28 showsthe electric circuit for this sensor

52 Relative Humidity HIH-4000 is a high precision humid-ity sensor which presents a near linear voltage output propor-tional to the measured relative humidity (RH) This compo-nent does not need additional circuits and elements to workWhen the sensor is fed the output voltage can be directlyconnected to the microprocessor (see Figure 27) It is easyto connect and its accuracy is plusmn5 for RH from 0 to 59and plusmn8 for RH from 60 to 100 The HIH-4000 shouldbe fed by a supply voltage of 5V The operating temperaturerange of this sensor is from minus40∘C to 85∘C Finally we shouldkeep in mind that the RH is a parameter which dependson the temperature For this reason we should apply thetemperature compensation over RH as (6) shows

119881out = 119881suppy sdot (00062 sdotRH () + 016)

True RH () = RH ()(10546 minus 000216 sdot 119905)

True RH () =(119881out119881suppy minus 016) 00062(10546 minus 000216 sdot 119905)

(8)

where 119881out is the output voltage as a function of the RH in and119881suppy is the voltage needed to feed the circuit (in our caseit is 5 V) RH () is the value of RH in True RH is the RHvalue in after the temperature compensation and 119905 is thetemperature expressed in ∘C

Figure 29 shows the relationship between the outputvoltage and the measured RH in Finally we have testedthe behavior of this sensor during 2 months Figure 30 showsthe relative humidity values gathered in this test bench

53 Wind Sensor To measure the wind speed we use a DCmotor as a generator mode where the rotation speed of theshaft becomes a voltage output which is proportional to thatspeed For a proper design we must consider several detailssuch as the size of the captors wind or the diameter of thecircle formed among others Figure 31 shows the design of


025

57510

12515

17520

22525

Seawater inorange light

With fuel inorange light

Seawater inwhite light

With fuel inwhite light

Seawater inviolet light

With fuel inviolet light

Out

put v

olta

ge (m

V)

Test 1Test 3Test 5Test 7Test 9


Figure 24 Output voltage as a function of the light and the presence of fuel

Table 5 Average value of the output voltage for the best cases

Output voltages (mV)Orange White Violet

Seawater With fuel Seawater With fuel Seawater With fuelAverage value 182 102 109 72 142 7Standard deviation 278088715 042163702 056764621 042163702 122927259 081649658

Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V

Figure 25 Sensor to measure the ambient temperature

our anemometer We used 3 hemispheres because it is thestructure that generates less turbulence Moreover we notethat a generator does not have a completely linear behaviorthe laminated iron core reaches the saturation limit when itreaches a field strength limit In this situation the voltage isnot proportional to the angular velocity After reaching thesaturation an increase in the voltage produces very little vari-ation approximating such behavior to a logarithmic behavior

0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)

Operating range of TC1047Useful operating range

minus40 minus15

Temperature (∘C)

Vout (V) = 0010 (V∘C) middot t (∘C) + 05V

Figure 26 Behavior of TC1047 and its equation

while(1)myADCTemp = ADCVal(1)myADCTemp = (myADCTemp lowast 2048)1024myADCTemp = myADCTemp lowast 0010 + 05sprintf(buf ldquodrdquo myADCValue)vTaskDelay(100)

Algorithm 4 Program code for reading analog input for ambienttemperature sensor


02468

1012141618202224262830

Days

Max temperatureAverage temperature

Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58

Figure 27 Test bench of the ambient temperature sensor

HIH-4000

Minimumload80kΩ Supply voltage

(5V)0V

minusve +veVout

Figure 28 Electrical connections for HIH-4000

To implement our system we use a miniature motorcapable of generating up to 3 volts when recording a valueof 12000 rpm The engine performance curve is shown inFigure 32

To express the wind speed we can do different ways Onone hand the rpm is a measure of angular velocity while msis a linear velocity To make this conversion of speeds weshould proceed as follows (see the following equation)

120596 (rpm) = 119891rot sdot 60 997888rarr 120596 (rads) = 120596 (rpm) sdot212058760 (9)

Finally the linear velocity in ms is expressed as shown in

V (ms) = 120596 (rads) sdot 119903 (10)

where 119891rot is the rotation frequency of anemometer in Hz119903 is the turning radius of the anemometer 120596 (rads) is theangular speed in rads and 120596 (rpm) is the angular speed inrevolutions per minute (rpm)

Given the characteristics of the engine operation and themathematical expressions the anemometer was tested during2 months The results collected by the sensor are shown inFigure 33

0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)

RH () compensated at 10∘C RH () compensated at 25∘CRH () compensated at 40∘C

Figure 29 RH in as a function of the output voltage compensatedin temperature

0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58

Figure 30 Relative humidity measured during two months

Figure 31 Design of our anemometer


020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)

Output voltage in motor (V)

Figure 32 Relationship between the output voltage in DC motorand the rotation speed

0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58

Figure 33 Measures of wind speed in a real environment

To measure the wind direction we need a vane Our vaneis formed by two SS94A1Hall sensorsmanufactured byHon-eywell (see Figure 34) which are located perpendicularlyApart from these two sensors the vane has a permanentmag-net on a shaft that rotates according to the wind direction

Our vane is based on detecting magnetic fields Eachsensor gives a linear output proportional to the number offield lines passing through it so when there is a linear outputwith higher value the detected magnetic field is higherAccording to the characteristics of this sensor it must be fedat least with 66V If the sensor is fed with 8V it obtains anoutput value of 4 volts per pin a ldquo0rdquo when it is not applied anymagnetic field and a lower voltage of 4 volts when the field isnegative We can distinguish 4 main situations

(i) Themagnetic field is negative when entering from theSouth Pole through the detector This happens whenthe detector is faced with the South Pole

(ii) A value greater than 4 volts output will be obtainedwhen the sensed magnetic field is positive (when thepositive pole of the magnet is faced with the Northpole)

(iii) The detector will give an output of 4 volts when thefield is parallel to the detector In this case the linesof the magnetic field do not pass through the detectorand therefore there is no magnetic field

Figure 34 Sensor hall

(iv) Finally when intermediate values are obtained weknow that the wind will be somewhere between thefour cardinal points

In our case we need to define a reference value when themagnetic field is not detected Therefore we will subtract 4to the voltage value that we obtain for each sensor This willallow us to distinguish where the vane is exactly pointingThese are the possible cases

(i) If the + pole of the magnet points to N rarr 1198672gt 0V

1198671= 0V

(ii) If the + pole of the magnet points to S rarr 1198672gt 0V

1198671= 0V

(iii) If the + pole of the magnet points to E rarr 1198671gt 0V

1198672= 0V

(iv) If the + pole of the magnet points to W rarr 1198671lt 0V

1198672= 0V

(v) When the + pole of themagnet points to intermediatepoints rarr 119867

1= 0V119867

2= 0V

Figure 35 shows the hall sensors diagram their positionsand the principles of operation

In order to calculate the wind direction we are going touse the operation for calculating the trigonometric tangent ofan angle (see the following equation)

tan120572 = 11986721198671997888rarr 120572 = tanminus11198672

1198671 (11)

where 1198672 is the voltage recorded by the Hall sensor 2 1198671 isthe voltage recorded by the Hall sensor 1 and 120572 representsthe wind direction taken as a reference the cardinal point ofeastThe values of the hall sensorsmay be positive or negativeand the wind direction will be calculated based on these


0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+

Figure 35 Diagram of operation for the wind direction sensor

H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)

Figure 36 Angle calculation as a function of the sensorsHall values

values Because for opposite angles the value of the tangentcalculation is the same after calculating themagnitude of thatangle the system must know the wind direction analyzingwhether the value of 1198671 and 1198672 is positive or negative Thevalue can be obtained using the settings shown in Figure 36

After setting the benchmarks and considering the linearbehavior of this sensor we have the following response (seeFigure 37) Depending on the position of the permanentmagnet the Hall sensors record the voltage values shown inFigure 38

54 Solar Radiation Sensor The solar radiation sensor isbased on the use of two light-dependent resistors (LDRs)Themain reason for using two LDRs is because the solar radiationvalue will be calculated as the average of the values recordedby each sensor The processor is responsible for conductingthis mathematical calculation Figure 40 shows the circuit

minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)

Magnetic field(Gauss)

Figure 37 Output voltage as a function of the magnetic field

005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)

Wind direction (deg)

minus3

minus25

minus2

minus15

minus1

minus05

Output voltageH2Output voltageH1

Figure 38 Output voltage of each sensor as a function the winddirection

diagram The circuit mounted in the laboratory to test itsoperation is shown in Figure 41

If we use the LDR placed at the bottom of the voltagedivider it will give us the maximum voltage when the LDR is


0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58

Figure 39 Measures of the wind direction in real environments

while(1)ADCVal LDR1 = ADCVal(1)ADCVal LDR2 = ADCVal(2)ADCVal LDR1 = ADCVal LDR1 lowast 20481024ADCVal LDR2 = ADCVal LDR2 lowast 20481024Light = (ADCVal LDR1 + ADCVal LDR2)2sprintf(buf ldquodrdquo ADCVal LDR1)sprintf(buf ldquodrdquo ADCVal LDR2)sprintf(buf ldquodrdquo Light)vTaskDelay(100)

Algorithm 5 Program code for the solar radiation sensor

in total darkness because it is having themaximumresistanceto the current flow In this situation 119881out registers the maxi-mumvalue If we use the LDR at the top of the voltage dividerthe result is the opposite We have chosen the first configu-ration The value of the solar radiation proportional to thedetected voltage is given by

119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)

To test the operation of this circuit we have developed asmall code that allows us to collect values from the sensors(see Algorithm 5) Finally we gathered measurements withthis sensor during 2 months Figure 39 shows the results ofthe wind direction obtained during this time

Figure 42 shows the voltage values collected during 2minutes As we can see both LDRs offer fairly similar valueshowever making their average value we can decrease theerror of the measurement due to their tolerances which insome cases may range from plusmn5 and plusmn10

Finally the sensor is tested for two months in a realenvironment Figure 43 shows the results obtained in this test

55 Rainfall Sensor LM331 is an integrated converter that canoperate using a single source with a quite acceptable accuracy

for a frequency range from 1Hz to 10 kHz This integratedcircuit is designed for both voltage to frequency conversionand frequency to voltage conversion Figure 44 shows theconversion circuit for frequency to voltage conversion

The input is formed by a high pass filter with a cutoff fre-quency much higher than the maximum input It makes thepin 6 to only see breaks in the input waveform and thus a setof positive and negative pulses over the 119881cc is obtained Fur-thermore the voltage on pin 7 is fixed by the resistive dividerand it is approximately (087 sdot 119881cc) When a negative pulsecauses a decrease in the voltage level of pin 6 to the voltagelevel of pin 7 an internal comparator switches its output to ahigh state and sets the internal Flip-Flop (FF) to the ON stateIn this case the output current is directed to pin 1

When the voltage level of pin 6 is higher than the voltagelevel of pin 7 the reset becomes zero again but the FF main-tains its previous state While the setting of the FF occursa transistor enters in its cut zone and 119862

119905begins to charge

through119877119905This condition is maintained (during tc) until the

voltage on pin 5 reaches 23 of 119881cc An instant later a secondinternal comparator resets the FF switching it to OFF thenthe transistor enters in driving zone and the capacitor isdischarged quicklyThis causes the comparator to switch backthe reset to zero This state is maintained until the FF is setwith the beginning of a new period of the input frequencyand the cycle is repeated

A low pass filter placed at the output pin gives as aresult a continuous 119881out level which is proportional to theinput frequency 119891in As its datasheet shows the relationshipbetween the input frequency and the output current is shownin

119868average = 119868pin1 sdot (11 sdot 119877119905 sdot 119862119905) sdot 119891in (13)

To finish the design of our system we should define therelation between the119891in and the amount of water In our casethe volume of each pocket is 10mL Thus the equivalencebetween both magnitudes is given by

1Hz 997888rarr 10mL of water

1 Lm2= 1mm 997888rarr 100Hz

(14)

Finally this system can be used for similar systems wherethe pockets for water can have biggerlower size and theamount of rain water and consequently the input frequencywill depend on it

The rain sensor was tested for two months in a realenvironment Figure 45 shows the results obtained

6 Mobile Platform and Network Performance

In order to connect and visualize the data in real-time wehave developed an Android application which allows the userto connect to a server and see the data In order to ensurea secure connection we have implemented a virtual privatenetwork (VPN) protected by authorized credentials [45]Thissection explains the network protocol that allows a user toconnect with the buoy in order to see the values in real-timeas well as the test bench performed in terms of network per-formance and the Android application developed


R1 = 1kΩ

Vcc = 5V

To microprocessor

R2 = 1kΩTo microprocessor

LDR1

LDR2

VLDR1

VLDR2Vlight = (12) middot (VLDR1 + VLDR 2)

Figure 40 Circuit diagram for the solar radiation sensor

Figure 41 Circuit used in our test bench

0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2

Average value of LDRs

100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54

Figure 42 Output voltage of both LDRs and the average value

61 Data Acquisition System Based on Android In order tostore the data in a server we have developed a Java applicationbased on Sockets The application that shows the activity ofthe sensors in real-time is developed in Android and it allowsthe request of data from the mobile devices The access fromcomputers can be performed through the web site embeddedin the FlyPort This section shows the protocol used to carry

0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58

Figure 43 Results of the solar radiation gathered during 2 monthsin a real environment

out this secure connection and the network performance inboth cases

The system consists of a sensor node (Client) located inthe buoy which is connected wirelessly to a data server (thisprocedure allows connecting more buoys to the system eas-ily)There is also aVNP server which acts as a security systemto allow external connections The data server is responsiblefor storing the data from the sensors and processing themlaterThe access to the data server ismanaged by aVPN serverthat controls the VPN access The server monitors all remoteaccess and the requests from any device In order to see thecontent of the database the user should connect to the dataserver following the process shown in Figure 46The connec-tion from a device is performed by an Android applicationdeveloped with this goal Firstly the user needs to establisha connection through a VPN The VPN server will check thevalidity of user credentials and will perform the authentica-tion and connection establishment After this the user canconnect to the data server to see the data stored or to thebuoy to see its status in real-time (both protocols are shown inFigure 46 one after the other consecutively) The connectionwith the buoy is performed using TCP sockets because italso allows us to save and store data from the sensors and


Balance with 2pockets for water

Frequency to voltagesensor with electric

contact

Receptacle forcollecting rainwater

Water sinks

Metal contact

Aluminumstructure to

protect the systemRainwater

RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi

Figure 44 Rainfall sensor and the basic electronic scheme

02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58

Figure 45 Results of rainfall gathered during 2 months in a realenvironment

process them for scientific studies The data inputoutput isperformed through InputStream and OutputStream objectsassociated with the Sockets The server creates a ServerSocketwith a port number as parameterwhich can be a number from1024 to 65534 (the port numbers from 1 to 1023 are reservedfor system services such as SSH SMTP FTP mail www andtelnet) that will be listening for incoming requests The TCPport used by the server in our system is 8080We should notethat each server must use a different port When the serveris active it waits for client connections We use the functionaccept () which is blocked until a client connects In that casethe system returns a Socket which is the connection with theclient Socket AskCliente = AskServeraccept()

In the remote device the application allows configuringthe client IP address (Buoy) and the TCP port used to estab-lish the connection (see Figure 47(a)) Our application dis-plays two buttons to start and stop the socket connection If

the connection was successful a message will confirm thatstate Otherwise the application will display amessage sayingthat the connection has failed In that moment we will beable to choose between data from water or data from theweather (see Figure 47(b)) These data are shown in differentwindows one for meteorological data (see Figure 47(c)) andwater data (see Figure 47(d))

Finally in order to test the network operation we carriedout a test (see Figure 48) during 6 minutes This test hasmeasured the bandwidth consumed when a user accesses tothe client through the website of node and through the socketconnection As Figure 47 shows when the access is per-formed through the socket connection the consumed band-width has a peak (33 kbps) at the beginning of the test Oncethe connection is done the consumed bandwidth decreasesdown to 3 kbps

The consumed bandwidth when the user is connected tothe website is 100 kbps In addition the connection betweensockets seems to be faster As a conclusion our applicationpresents lower bandwidth consumption than thewebsite hos-ted in the memory of the node

7 Conclusion and Future Work

Posidonia and seagrasses are some of the most importantunderwater areas with high ecological value in charge ofprotecting the coastline from erosion They also protect theanimals and plants living there

In this paper we have presented an oceanographic multi-sensor buoy which is able to measure all important param-eters that can affect these natural areas The buoy is basedon several low cost sensors which are able to collect datafrom water and from the weather The data collected for allsensors are processed using a microcontroller and stored in a


Internet

Client VPN server

VPN server

(2) Open TPC socket

(3) Request to read stored data(4) Write data inthe database

(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket

(3) Acceptingconnections

(4) Connection requestto send data

(4) Connection established(5) Request data

(1) Open VPN connection

Data server

Data serverBuoy

(1) Start server(2) Open TPC socket

(3) Accepting connections

(5) Read data

(5) Read data

(5) Read data fromthe database

(6) Close socket(11) Close socket

(12) Close VPN connection

(7) Open TCP socket(8) Request to read real-time data(9) Connection established(10) Request data

ACK close connection

Connection request

Connection request

Connection request

Connect and login the VPN server

VPN server authentication establishment of encrypted network and assignment of new IP address

Send data

Close connection with VPN server

Figure 46 Protocol to perform a connection with the buoy using a VPN

(a) (b) (c) (d)

Figure 47 Screenshot of our Android applications to visualize the data from the sensors


0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)

BW-access through socketBW-access through website

0 30 60 90 120 150 180 210 240 270 300 330

Figure 48 Consumed bandwidth

database held in a server The buoy is wirelessly connectedwith the base station through a wireless a FlyPort moduleFinally the individual sensors the network operation andmobile application to gather data from buoy are tested in acontrolled scenario

After analyzing the operation and performance of oursensors we are sure that the use of this system could be veryuseful to protect and prevent several types of damage that candestroy these habitats

The first step of our future work will be the installationof the whole system in a real environment near Alicante(Spain) We would also like to adapt this system for moni-toring and controlling the fish feeding process in marine fishfarms in order to improve their sustainability [46] We willimprove the system by creating a bigger network for combin-ing the data of both the multisensor buoy and marine fishfarms and apply some algorithms to gather the data [47] Inaddition we would like to apply new techniques for improv-ing the network performance [48] security in transmitteddata [49] and its size by adding an ad hoc network to thebuoy [50] as well as some other parameters as decreasing thepower consumption [51]

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

This work has been supported by the ldquoMinisterio de Cienciae Innovacionrdquo through the ldquoPlan Nacional de I+D+i 2008ndash2011rdquo in the ldquoSubprograma de Proyectos de InvestigacionFundamentalrdquo Project TEC2011-27516

References

[1] D Bri H Coll M Garcia and J Lloret ldquoA wireless IPmultisen-sor deploymentrdquo Journal on Advances in Networks and Servicesvol 3 no 1-2 pp 125ndash139 2010

[2] D Bri M Garcia J Lloret and P Dini ldquoReal deployments ofwireless sensor networksrdquo inProceedings of the 3rd InternationalConference on Sensor Technologies and Applications (SENSOR-COMM rsquo09) pp 415ndash423 Athens Ga USA June 2009

[3] A H Mohsin K Abu Bakar A Adekiigbe and K Z GhafoorldquoA survey of energy-aware routing protocols in mobile Ad-hoc networks trends and challengesrdquo Network Protocols andAlgorithms vol 4 no 2 pp 82ndash107 2012

[4] T Wang Y Zhang Y Cui and Y Zhou ldquoA novel protocolof energy-constrained sensor network for emergency monitor-ingrdquo International Journal of Sensor Networks vol 15 no 3 pp171ndash182 2014

[5] K Xing W Wu L Ding L Wu and J Willson ldquoAn efficientrouting protocol based on consecutive forwarding predictionin delay tolerant networksrdquo International Journal of SensorNetworks vol 15 no 2 pp 73ndash82 2014

[6] M Fereydooni M Sabaei and G Babazadeh ldquoEnergy efficienttopology control in wireless sensor networks with consideringinterference and traffic loadrdquo Ad Hoc amp Sensor Wireless Net-works vol 25 no 3-4 pp 289ndash308 2015

[7] G Anastasi M Conti M Di Francesco and A PassarellaldquoEnergy conservation in wireless sensor networks a surveyrdquoAdHoc Networks vol 7 no 3 pp 537ndash568 2009

[8] N D Nguyen V Zalyubovskiy M T Ha T D Le and HChoo ldquoEnergy-efficient models for coverage problem in sensornetworks with adjustable rangesrdquo Ad-Hoc amp Sensor WirelessNetworks vol 16 no 1ndash3 pp 1ndash28 2012

[9] Y Liu Q-A Zeng and Y-H Wang ldquoEnergy-efficient datafusion technique and applications in wireless sensor networksrdquoJournal of Sensors vol 2015 Article ID 903981 2 pages 2015

[10] T K Jain D S Saini and S V Bhooshan ldquoLifetime optimiza-tion of a multiple sink wireless sensor network through energybalancingrdquo Journal of Sensors vol 2015 Article ID 921250 6pages 2015

[11] G Zhou L Huang W Li and Z Zhu ldquoHarvesting ambientenvironmental energy for wireless sensor networks a surveyrdquoJournal of Sensors vol 2014 Article ID 815467 20 pages 2014

[12] H Legakis M Mehmet-Ali and J F Hayes ldquoLifetime analysisfor wireless sensor networksrdquo International Journal of SensorNetworks vol 17 no 1 pp 1ndash16 2015

[13] C Albaladejo P Sanchez A Iborra F Soto J A Lopez and RTorres ldquoWireless sensor networks for oceanographic monitor-ing a systematic reviewrdquo Sensors vol 10 no 7 pp 6948ndash69682010

[14] B Dong ldquoA survey of underwater wireless sensor networksrdquoin Proceedings of the CAHSI Annual Meeting p 52 MountainView Calif USA January 2009

[15] G Xu W Shen and X Wang ldquoApplications of wireless sensornetworks inmarine environmentmonitoring a surveyrdquo Sensorsvol 14 no 9 pp 16932ndash16954 2014

[16] A Gkikopouli G Nikolakopoulos and S Manesis ldquoA surveyon underwater wireless sensor networks and applicationsrdquo inProceedings of the 20th Mediterranean Conference on ControlandAutomation (MED rsquo12) pp 1147ndash1154 Barcelona Spain July2012

[17] I F Akyildiz D Pompili and TMelodia ldquoUnderwater acousticsensor networks research challengesrdquo Ad Hoc Networks vol 3no 3 pp 257ndash279 2005

[18] MWaycott CMDuarte T J B Carruthers et al ldquoAcceleratingloss of seagrasses across the globe threatens coastal ecosystemsrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 106 no 30 pp 12377ndash12381 2009


[19] R J Orth T J B Carruthers W C Dennison et al ldquoA globalcrisis for seagrass ecosystemsrdquo Bioscience vol 56 no 12 pp987ndash996 2006

[20] J E Campbell E A Lacey R A Decker S Crooks and J WFourqurean ldquoCarbon storage in seagrass beds of Abu DhabiUnited Arab Emiratesrdquo Estuaries and Coasts vol 38 no 1 pp242ndash251 2015

[21] L Zhang Z Zhao D Li Q Liu and L Cui ldquoWildlife moni-toring using heterogeneous wireless communication networkrdquoAd-Hocamp SensorWireless Networks vol 18 no 3-4 pp 159ndash1792013

[22] Facility for Automated Intelligent Monitoring of Marine Sys-tems (FAIMMS) in IMOS Ocean Portal 2014 httpimosorgauimplementationhtml

[23] M Ayaz I Baig A Abdullah and I Faye ldquoA survey on routingtechniques in underwater wireless sensor networksrdquo Journal ofNetwork and Computer Applications vol 34 no 6 pp 1908ndash1927 2011

[24] B OrsquoFlynn R Martinez J Cleary et al ldquoSmartCoast a wirelesssensor network for water quality monitoringrdquo in Proceedings ofthe 32nd IEEE Conference on Local Computer Networks (LCNrsquo07) pp 815ndash816 Dublin Ireland October 2007

[25] S Kroger S Piletsky and A P F Turner ldquoBiosensors formarinepollution research monitoring and controlrdquo Marine PollutionBulletin vol 45 no 1ndash12 pp 24ndash34 2002

[26] SThiemann andH Kaufmann ldquoLake water qualitymonitoringusing hyperspectral airborne datamdasha semiempirical multisen-sor and multitemporal approach for the Mecklenburg LakeDistrict Germanyrdquo Remote Sensing of Environment vol 81 no2-3 pp 228ndash237 2002

[27] B OrsquoFlynn F Regan A Lawlor J Wallace J Torres and COrsquoMathuna ldquoExperiences and recommendations in deployinga real-time water quality monitoring systemrdquo MeasurementScience and Technology vol 21 no 12 Article ID 124004 2010

[28] F N Guttler S Niculescu and F Gohin ldquoTurbidity retrievaland monitoring of Danube Delta waters using multi-sensoroptical remote sensing data an integrated view from the deltaplain lakes to thewesternndashnorthwestern Black Sea coastal zonerdquoRemote Sensing of Environment vol 132 pp 86ndash101 2013

[29] C Albaladejo F Soto R Torres P Sanchez and J A LopezldquoA low-cost sensor buoy system for monitoring shallow marineenvironmentsrdquo Sensors vol 12 no 7 pp 9613ndash9634 2012

[30] C Jianxin G Wei and H Hui ldquoParameters measurmentof marine power system based on multi-sensors data fusiontheoryrdquo in Proceedings of the 8th International Conference onInformation Communications and Signal Processing (ICICS rsquo11)Singapore December 2011

[31] M Vespe M Sciotti F Burro G Battistello and S SorgeldquoMaritime multi-sensor data association based on geographicand navigational knowledgerdquo in Proceedings of the IEEE RadarConference (RADAR rsquo08) pp 1ndash6 Rome Italy May 2008

[32] R S Sousa-Lima T F Norris J N Oswald andD P FernandesldquoA review and inventory of fixed autonomous recorders forpassive acoustic monitoring of marine mammalsrdquo AquaticMammals vol 39 no 1 pp 23ndash53 2013

[33] J Lloret ldquoUnderwater sensor nodes and networksrdquo Sensors vol13 no 9 pp 11782ndash11796 2013

[34] Flyport features Openpicus website 2014 httpstoreopen-picuscomopenpicusprodottiaspxcprod=OP015351

[35] J Lloret M Garcia D Bri and S Sendra ldquoA wireless sensornetwork deployment for rural and forest fire detection andverificationrdquo Sensors vol 9 no 11 pp 8722ndash8747 2009

[36] J Lloret I Bosch S Sendra and A Serrano ldquoA wireless sensornetwork for vineyard monitoring that uses image processingrdquoSensors vol 11 no 6 pp 6165ndash6196 2011

[37] L Karim A Anpalagan N Nasser and J Almhana ldquoSensor-based M2M agriculture monitoring systems for developingcountries state and challengesrdquo Network Protocols and Algo-rithms vol 5 no 3 pp 68ndash86 2013

[38] S Sendra F Llario L Parra and J Lloret ldquoSmart wirelesssensor network to detect and protect sheep and goats to wolfattacksrdquo Recent Advances in Communications and NetworkingTechnology vol 2 no 2 pp 91ndash101 2013

[39] S Sendra A T Lloret J Lloret and J J P C Rodrigues ldquoAwireless sensor network deployment to detect the degenerationof cement used in constructionrdquo International Journal of AdHocand Ubiquitous Computing vol 15 no 1ndash3 pp 147ndash160 2014

[40] P Jiang J Winkley C Zhao R Munnoch G Min and L TYang ldquoAn intelligent information forwarder for healthcare bigdata systems with distributed wearable sensorsrdquo IEEE SystemsJournal 2014

[41] N Lopez-Ruiz J Lopez-TorresMA Rodriguez I P deVargas-Sansalvador and A Martinez-Olmos ldquoWearable system formonitoring of oxygen concentration in breath based on opticalsensorrdquo IEEE Sensors Journal vol 15 no 7 pp 4039ndash4045 2015

[42] L Parra S Sendra J Lloret and J J P C Rodrigues ldquoLow costwireless sensor network for salinity monitoring in mangroveforestsrdquo in Proceedings of the IEEE SENSORS pp 126ndash129 IEEEValencia Spain November 2014

[43] L Parra S Sendra V Ortuno and J Lloret ldquoLow-cost con-ductivity sensor based on two coilsrdquo in Proceedings of the1st International Conference on Computational Science andEngineering (CSE rsquo13) pp 107ndash112 Valencia Spain August 2013

[44] S Sendra L Parra VOrtuno and J Lloret ldquoA low cost turbiditysensor developmentrdquo in Proceedings of the 7th InternationalConference on Sensor Technologies and Applications (SENSOR-COMM rsquo13) pp 266ndash272 Barcelona Spain August 2013

[45] J-L Lin K-S Hwang and Y S Hsiao ldquoA synchronous displayof partitioned images broadcasting system via VPN transmis-sionrdquo IEEE Systems Journal vol 8 no 4 pp 1031ndash1039 2014

[46] M Garcia S Sendra G Lloret and J Lloret ldquoMonitoring andcontrol sensor system for fish feeding in marine fish farmsrdquo IETCommunications vol 5 no 12 pp 1682ndash1690 2011

[47] N Meghanathan and P Mumford ldquoCentralized and distributedalgorithms for stability-based data gathering in mobile sensornetworksrdquo Network Protocols and Algorithms vol 5 no 4 pp84ndash116 2013

[48] D Rosario R Costa H Paraense et al ldquoA hierarchical multi-hop multimedia routing protocol for wireless multimedia sen-sor networksrdquo Network Protocols and Algorithms vol 4 no 4pp 44ndash64 2012

[49] R Dutta and B Annappa ldquoProtection of data in unsecuredpublic cloud environment with open vulnerable networksusing threshold-based secret sharingrdquo Network Protocols andAlgorithms vol 6 no 1 pp 58ndash75 2014

[50] M Garcia S endra M Atenas and J Lloret ldquoUnderwaterwireless ad-hoc networks a surveyrdquo inMobile AdHocNetworksCurrent Status and Future Trends pp 379ndash411 CRC Press 2011

[51] S Sendra J Lloret M Garcıa and J F Toledo ldquoPower savingand energy optimization techniques for wireless sensor net-worksrdquo Journal of Communications vol 6 no 6 pp 439ndash4592011

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Active and Passive Electronic Components

Control Scienceand Engineering

Journal of



RotatingMachinery


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



Table 1 Important parameters for underwater WSNs

Node position Parameters measured in underwater environments by WSNsSurface Water column Sea bed

Important parameters

Swell height Temperature TemperatureSwell direction Pressure Pressure

Hydrocarbons ppm Dissolved oxygen Dissolved oxygenAir temperature Salinity (or conductivity) Redox potentialAir pressure mb Turbidity pHWind speed Chlorophyll Hydrogen sulfide

Wind direction Phosphate VibrationsPrecipitation Nitrate Movement

Atmospheric pressure pHRelative humidity Blue-green algae

RH solar radiation AmmoniumammoniaSurface salinity (or conductivity) Chloride

RhodamineDissolved organic carbon

Dissolver metals

Generally underwater WSNs are used to cover higher areasthan terrestrial WSNs [8] the energy consumption will behigher and the signals are attenuated in the underwater envi-ronments So it is important to implement energy-efficienttechniques in data processing [9 10] and energy harvestingsolutions [11] to prolong the network lifetime [12] and net-work stabilityThe price of devices used in underwaterWSNsis usually higher than in terrestrialWSNs In addition sensornodes in underwater WSNs are placed in a specific placealong the water column so flotation andmooring devices areneeded [13] Finally the wireless communication technologyin terrestrial WSNs use different radio frequencies howeverin underwater WSNs the water produces an important atten-uation on radio frequencies so there are many deploymentsusing other technologies such as sound or light [14]

Underwater sensors can be placed at the bottom at thesurface or at different points along the water column Thesensed parameters can change depending on the point wherethe sensors are placed and the objective of the WSN Forexample in environments without light there is no need tomeasure chlorophyll and in environments far from humanimpact there is no need to measure the presence of hydrocar-bons Table 1 shows the main parameters that can be sensedas a function of the place where sensor nodes are placed in thewater column Although there is a large list of parameters themost common ones are temperature (119879) pH turbidity anddissolved oxygen (DO) [13]

According to [15] underwater WSNs are mainly appliedto general ocean sensing andmonitoring water quality mon-itoring fish farms monitoring coral reef monitoring andmarine shellfish monitoring (see Figure 1) However the the-oretical applications are wider [16 17] We can highlight theocean sampling networks environmental monitoring disas-ter prevention assisted navigationmine reconnaissancemil-itary purposes or undersea explorations but there are veryfew works published showing real deployments Combining

General ocean sensing andmonitoring

(5000)Water quality monitoring

(3182)

Fish farm monitoring

(908)

Coral reef monitoring

(455)

Marine shellfish

monitoring(455)

Figure 1 Main applications of underwater WSNs

some of these parameters we can find several important app-lications which could help us to protect sensitive areas suchas seagrasses and Posidonia meadows

Seagrasses meadows are considered an important ecosys-tem because they are composed of plants that lived in under-water environments Since 1980 there has been a decrease of29 of the colonized areas due to several threats The lossrate is 110 km2year [18]Themost important parameters thatrestrict the potential area for seagrasses are light exposure(10 of surface radiation) physical exposure (maximumcurrent 15ms) substratum (gravel sand or mud) temper-ature (minus1∘C in winter to 30∘C in summer) and salinity (5 to45 PSU) These data correspond to the species which presentthe most restrictive needs The most affected environment isthe coastal area which plays an important role

The main functions of these ecosystems are

(i) sediment and nutrient retention [19]

(ii) nursery for juvenile fish [19]




















2 Related Work




























Solar panels










Float of buoy

Water


Opening that



to support






119881out (119905) = 119881cc1198770 sdot 119890119861(1119905minus11199050)

1198770 sdot 119890119861(1119905minus11199050) + 119877sup

(1)






119905 (∘C)

=1199050


minus 273

(2)

where 119881119877NTC









Temperature

Rain

Wind

Solar radiation

Relative humidity

Fuel detection

Water temperature

Turbidity

Salinity

Solar panel

Battery

Regulator

DC converter



Power supply system


Server

Mainland

WiFi





Vcc = 5V

R1 = 1kΩ

minusT

To microprocessor

RNTC = 10kΩ






05

1015202530354045

42 43 44 45 46 47 48Output voltage (V)

Tem

pera

ture

(∘C)




Wire Diam 08mm 08mm

Size and core











005

115

225

335

445

0 5 10 15 20 25 30 35 40 45

Out

put v

olta

ge (V

)

Salinity (ppm)

10kHz

150kHz

250kHz500kHz

590kHz

625kHz375kHz750kHz


Induced signal

Input signal



0

05

1

0

10

026

40

528

079

21

056

132

158

41

848

211

22

376

264

290

43

168

343

23

696

396

422

44

488

475

25

016

528

554

45

808

607

26

336

66

686

47

128

739

27

656

792

818

48

448

871

28

976

924

950

49

768

100

3210

296

105

610

824

110

8811

352

116

16

Am

plitu

de si

ne w

ave

Am

p litu

de P

WM

Time (120583s)


Voutput

R1 R2

R3

R4C1

C2

C3 C4


R3 = 68kΩR4 = 18kΩ

C1 = 100pFC2 = 39pF

C1 = 100pFC2 = 100pF

Q = 081348921682Q = 0800164622228

10kΩ10120583F


PWM fromFlyPort +

minus

+minus






Bode diagram

Mag

nitu

de (d

B)

40

0

minus40

minus80

minus120

minus160100E0 100E31E3 10E3 1E3 10E6

100E0 100E31E3 10E3 1E3 10E6

Phas

e (de

g)

180

120

60

0

Frequency (Hz)

Frequency (Hz)











119881out 1 = 11788 sdot 119878 + 06037 1198772= 09751 (3)

119881out 2 = 02387 sdot 119878 + 33457 1198772= 09813 (4)

119881out 3 = 00625 sdot 119878 + 523 1198772= 09872 (5)



012345678

0 5 10 15 20 25 30 35 40

Out

put v

olta

ge (V

)

Salinity (ppm)


05

101520253035404550

0 5 10 15 20 25 30 35 40 45 50

Pred

icte

d sa

linity

(ppm

)






R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω




1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385








3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)







0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation




























2 Related Work




























Solar panels










Float of buoy

Water


Opening that



to support






119881out (119905) = 119881cc1198770 sdot 119890119861(1119905minus11199050)

1198770 sdot 119890119861(1119905minus11199050) + 119877sup

(1)






119905 (∘C)

=1199050


minus 273

(2)

where 119881119877NTC









Temperature

Rain

Wind

Solar radiation

Relative humidity

Fuel detection

Water temperature

Turbidity

Salinity

Solar panel

Battery

Regulator

DC converter



Power supply system


Server

Mainland

WiFi





Vcc = 5V

R1 = 1kΩ

minusT

To microprocessor

RNTC = 10kΩ






05

1015202530354045

42 43 44 45 46 47 48Output voltage (V)

Tem

pera

ture

(∘C)




Wire Diam 08mm 08mm

Size and core











005

115

225

335

445

0 5 10 15 20 25 30 35 40 45

Out

put v

olta

ge (V

)

Salinity (ppm)

10kHz

150kHz

250kHz500kHz

590kHz

625kHz375kHz750kHz


Induced signal

Input signal



0

05

1

0

10

026

40

528

079

21

056

132

158

41

848

211

22

376

264

290

43

168

343

23

696

396

422

44

488

475

25

016

528

554

45

808

607

26

336

66

686

47

128

739

27

656

792

818

48

448

871

28

976

924

950

49

768

100

3210

296

105

610

824

110

8811

352

116

16

Am

plitu

de si

ne w

ave

Am

p litu

de P

WM

Time (120583s)


Voutput

R1 R2

R3

R4C1

C2

C3 C4


R3 = 68kΩR4 = 18kΩ

C1 = 100pFC2 = 39pF

C1 = 100pFC2 = 100pF

Q = 081348921682Q = 0800164622228

10kΩ10120583F


PWM fromFlyPort +

minus

+minus






Bode diagram

Mag

nitu

de (d

B)

40

0

minus40

minus80

minus120

minus160100E0 100E31E3 10E3 1E3 10E6

100E0 100E31E3 10E3 1E3 10E6

Phas

e (de

g)

180

120

60

0

Frequency (Hz)

Frequency (Hz)











119881out 1 = 11788 sdot 119878 + 06037 1198772= 09751 (3)

119881out 2 = 02387 sdot 119878 + 33457 1198772= 09813 (4)

119881out 3 = 00625 sdot 119878 + 523 1198772= 09872 (5)



012345678

0 5 10 15 20 25 30 35 40

Out

put v

olta

ge (V

)

Salinity (ppm)


05

101520253035404550

0 5 10 15 20 25 30 35 40 45 50

Pred

icte

d sa

linity

(ppm

)






R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω




1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385








3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)







0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation

































Solar panels










Float of buoy

Water


Opening that



to support






119881out (119905) = 119881cc1198770 sdot 119890119861(1119905minus11199050)

1198770 sdot 119890119861(1119905minus11199050) + 119877sup

(1)






119905 (∘C)

=1199050


minus 273

(2)

where 119881119877NTC









Temperature

Rain

Wind

Solar radiation

Relative humidity

Fuel detection

Water temperature

Turbidity

Salinity

Solar panel

Battery

Regulator

DC converter



Power supply system


Server

Mainland

WiFi





Vcc = 5V

R1 = 1kΩ

minusT

To microprocessor

RNTC = 10kΩ






05

1015202530354045

42 43 44 45 46 47 48Output voltage (V)

Tem

pera

ture

(∘C)




Wire Diam 08mm 08mm

Size and core











005

115

225

335

445

0 5 10 15 20 25 30 35 40 45

Out

put v

olta

ge (V

)

Salinity (ppm)

10kHz

150kHz

250kHz500kHz

590kHz

625kHz375kHz750kHz


Induced signal

Input signal



0

05

1

0

10

026

40

528

079

21

056

132

158

41

848

211

22

376

264

290

43

168

343

23

696

396

422

44

488

475

25

016

528

554

45

808

607

26

336

66

686

47

128

739

27

656

792

818

48

448

871

28

976

924

950

49

768

100

3210

296

105

610

824

110

8811

352

116

16

Am

plitu

de si

ne w

ave

Am

p litu

de P

WM

Time (120583s)


Voutput

R1 R2

R3

R4C1

C2

C3 C4


R3 = 68kΩR4 = 18kΩ

C1 = 100pFC2 = 39pF

C1 = 100pFC2 = 100pF

Q = 081348921682Q = 0800164622228

10kΩ10120583F


PWM fromFlyPort +

minus

+minus






Bode diagram

Mag

nitu

de (d

B)

40

0

minus40

minus80

minus120

minus160100E0 100E31E3 10E3 1E3 10E6

100E0 100E31E3 10E3 1E3 10E6

Phas

e (de

g)

180

120

60

0

Frequency (Hz)

Frequency (Hz)











119881out 1 = 11788 sdot 119878 + 06037 1198772= 09751 (3)

119881out 2 = 02387 sdot 119878 + 33457 1198772= 09813 (4)

119881out 3 = 00625 sdot 119878 + 523 1198772= 09872 (5)



012345678

0 5 10 15 20 25 30 35 40

Out

put v

olta

ge (V

)

Salinity (ppm)


05

101520253035404550

0 5 10 15 20 25 30 35 40 45 50

Pred

icte

d sa

linity

(ppm

)






R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω




1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385








3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)







0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Float of buoy

Water


Opening that



to support






119881out (119905) = 119881cc1198770 sdot 119890119861(1119905minus11199050)

1198770 sdot 119890119861(1119905minus11199050) + 119877sup

(1)






119905 (∘C)

=1199050


minus 273

(2)

where 119881119877NTC









Temperature

Rain

Wind

Solar radiation

Relative humidity

Fuel detection

Water temperature

Turbidity

Salinity

Solar panel

Battery

Regulator

DC converter



Power supply system


Server

Mainland

WiFi





Vcc = 5V

R1 = 1kΩ

minusT

To microprocessor

RNTC = 10kΩ






05

1015202530354045

42 43 44 45 46 47 48Output voltage (V)

Tem

pera

ture

(∘C)




Wire Diam 08mm 08mm

Size and core











005

115

225

335

445

0 5 10 15 20 25 30 35 40 45

Out

put v

olta

ge (V

)

Salinity (ppm)

10kHz

150kHz

250kHz500kHz

590kHz

625kHz375kHz750kHz


Induced signal

Input signal



0

05

1

0

10

026

40

528

079

21

056

132

158

41

848

211

22

376

264

290

43

168

343

23

696

396

422

44

488

475

25

016

528

554

45

808

607

26

336

66

686

47

128

739

27

656

792

818

48

448

871

28

976

924

950

49

768

100

3210

296

105

610

824

110

8811

352

116

16

Am

plitu

de si

ne w

ave

Am

p litu

de P

WM

Time (120583s)


Voutput

R1 R2

R3

R4C1

C2

C3 C4


R3 = 68kΩR4 = 18kΩ

C1 = 100pFC2 = 39pF

C1 = 100pFC2 = 100pF

Q = 081348921682Q = 0800164622228

10kΩ10120583F


PWM fromFlyPort +

minus

+minus






Bode diagram

Mag

nitu

de (d

B)

40

0

minus40

minus80

minus120

minus160100E0 100E31E3 10E3 1E3 10E6

100E0 100E31E3 10E3 1E3 10E6

Phas

e (de

g)

180

120

60

0

Frequency (Hz)

Frequency (Hz)











119881out 1 = 11788 sdot 119878 + 06037 1198772= 09751 (3)

119881out 2 = 02387 sdot 119878 + 33457 1198772= 09813 (4)

119881out 3 = 00625 sdot 119878 + 523 1198772= 09872 (5)



012345678

0 5 10 15 20 25 30 35 40

Out

put v

olta

ge (V

)

Salinity (ppm)


05

101520253035404550

0 5 10 15 20 25 30 35 40 45 50

Pred

icte

d sa

linity

(ppm

)






R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω




1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385








3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)







0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Temperature

Rain

Wind

Solar radiation

Relative humidity

Fuel detection

Water temperature

Turbidity

Salinity

Solar panel

Battery

Regulator

DC converter



Power supply system


Server

Mainland

WiFi





Vcc = 5V

R1 = 1kΩ

minusT

To microprocessor

RNTC = 10kΩ






05

1015202530354045

42 43 44 45 46 47 48Output voltage (V)

Tem

pera

ture

(∘C)




Wire Diam 08mm 08mm

Size and core











005

115

225

335

445

0 5 10 15 20 25 30 35 40 45

Out

put v

olta

ge (V

)

Salinity (ppm)

10kHz

150kHz

250kHz500kHz

590kHz

625kHz375kHz750kHz


Induced signal

Input signal



0

05

1

0

10

026

40

528

079

21

056

132

158

41

848

211

22

376

264

290

43

168

343

23

696

396

422

44

488

475

25

016

528

554

45

808

607

26

336

66

686

47

128

739

27

656

792

818

48

448

871

28

976

924

950

49

768

100

3210

296

105

610

824

110

8811

352

116

16

Am

plitu

de si

ne w

ave

Am

p litu

de P

WM

Time (120583s)


Voutput

R1 R2

R3

R4C1

C2

C3 C4


R3 = 68kΩR4 = 18kΩ

C1 = 100pFC2 = 39pF

C1 = 100pFC2 = 100pF

Q = 081348921682Q = 0800164622228

10kΩ10120583F


PWM fromFlyPort +

minus

+minus






Bode diagram

Mag

nitu

de (d

B)

40

0

minus40

minus80

minus120

minus160100E0 100E31E3 10E3 1E3 10E6

100E0 100E31E3 10E3 1E3 10E6

Phas

e (de

g)

180

120

60

0

Frequency (Hz)

Frequency (Hz)











119881out 1 = 11788 sdot 119878 + 06037 1198772= 09751 (3)

119881out 2 = 02387 sdot 119878 + 33457 1198772= 09813 (4)

119881out 3 = 00625 sdot 119878 + 523 1198772= 09872 (5)



012345678

0 5 10 15 20 25 30 35 40

Out

put v

olta

ge (V

)

Salinity (ppm)


05

101520253035404550

0 5 10 15 20 25 30 35 40 45 50

Pred

icte

d sa

linity

(ppm

)






R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω




1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385








3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)







0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












05

1015202530354045

42 43 44 45 46 47 48Output voltage (V)

Tem

pera

ture

(∘C)




Wire Diam 08mm 08mm

Size and core











005

115

225

335

445

0 5 10 15 20 25 30 35 40 45

Out

put v

olta

ge (V

)

Salinity (ppm)

10kHz

150kHz

250kHz500kHz

590kHz

625kHz375kHz750kHz


Induced signal

Input signal



0

05

1

0

10

026

40

528

079

21

056

132

158

41

848

211

22

376

264

290

43

168

343

23

696

396

422

44

488

475

25

016

528

554

45

808

607

26

336

66

686

47

128

739

27

656

792

818

48

448

871

28

976

924

950

49

768

100

3210

296

105

610

824

110

8811

352

116

16

Am

plitu

de si

ne w

ave

Am

p litu

de P

WM

Time (120583s)


Voutput

R1 R2

R3

R4C1

C2

C3 C4


R3 = 68kΩR4 = 18kΩ

C1 = 100pFC2 = 39pF

C1 = 100pFC2 = 100pF

Q = 081348921682Q = 0800164622228

10kΩ10120583F


PWM fromFlyPort +

minus

+minus






Bode diagram

Mag

nitu

de (d

B)

40

0

minus40

minus80

minus120

minus160100E0 100E31E3 10E3 1E3 10E6

100E0 100E31E3 10E3 1E3 10E6

Phas

e (de

g)

180

120

60

0

Frequency (Hz)

Frequency (Hz)











119881out 1 = 11788 sdot 119878 + 06037 1198772= 09751 (3)

119881out 2 = 02387 sdot 119878 + 33457 1198772= 09813 (4)

119881out 3 = 00625 sdot 119878 + 523 1198772= 09872 (5)



012345678

0 5 10 15 20 25 30 35 40

Out

put v

olta

ge (V

)

Salinity (ppm)


05

101520253035404550

0 5 10 15 20 25 30 35 40 45 50

Pred

icte

d sa

linity

(ppm

)






R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω




1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385








3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)







0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

05

1

0

10

026

40

528

079

21

056

132

158

41

848

211

22

376

264

290

43

168

343

23

696

396

422

44

488

475

25

016

528

554

45

808

607

26

336

66

686

47

128

739

27

656

792

818

48

448

871

28

976

924

950

49

768

100

3210

296

105

610

824

110

8811

352

116

16

Am

plitu

de si

ne w

ave

Am

p litu

de P

WM

Time (120583s)


Voutput

R1 R2

R3

R4C1

C2

C3 C4


R3 = 68kΩR4 = 18kΩ

C1 = 100pFC2 = 39pF

C1 = 100pFC2 = 100pF

Q = 081348921682Q = 0800164622228

10kΩ10120583F


PWM fromFlyPort +

minus

+minus






Bode diagram

Mag

nitu

de (d

B)

40

0

minus40

minus80

minus120

minus160100E0 100E31E3 10E3 1E3 10E6

100E0 100E31E3 10E3 1E3 10E6

Phas

e (de

g)

180

120

60

0

Frequency (Hz)

Frequency (Hz)











119881out 1 = 11788 sdot 119878 + 06037 1198772= 09751 (3)

119881out 2 = 02387 sdot 119878 + 33457 1198772= 09813 (4)

119881out 3 = 00625 sdot 119878 + 523 1198772= 09872 (5)



012345678

0 5 10 15 20 25 30 35 40

Out

put v

olta

ge (V

)

Salinity (ppm)


05

101520253035404550

0 5 10 15 20 25 30 35 40 45 50

Pred

icte

d sa

linity

(ppm

)






R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω




1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385








3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)







0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation

















119881out 1 = 11788 sdot 119878 + 06037 1198772= 09751 (3)

119881out 2 = 02387 sdot 119878 + 33457 1198772= 09813 (4)

119881out 3 = 00625 sdot 119878 + 523 1198772= 09872 (5)



012345678

0 5 10 15 20 25 30 35 40

Out

put v

olta

ge (V

)

Salinity (ppm)


05

101520253035404550

0 5 10 15 20 25 30 35 40 45 50

Pred

icte

d sa

linity

(ppm

)






R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω




1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385








3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)







0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










R3

Phot

odio

de S186

P

21

18V

D1

D2

TSUS5400C1

0

0

0

0

0

GN

DG

ND

VoutVin

2

33

1 VoutVin

LM7805

LM7815

R1

R2

C4

100nF

100nF

C3

C2

330nF

330nF

10Ω

100 kΩ33Ω




1 0 00722 3633 2373 11044 6014 17533 9725 23210 1236 26066 1427 32666 1718 607 385








3

35

4

45

5

55

6

0 100 200 300 400

Out

put v

olta

ge (V

)

Turbidity (NTU)







0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turb

idity

mea

sure

d in

turb

idity

sens

or (N

TU)







Source

of light

Vcc Vcc

++

+ Vout minus

minusminus

+ Vr minus

1kΩ

1kΩ

100 kΩ

VccVout

Phot

odio

de

FlyPort








Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Seawater

Fuel








0

2mL4mL

6mL8mL10mL

02468

101214161820


Out

put v

olta

ge (m

V)

Light colour







(8)





025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










025

57510

12515

17520

22525







Out

put v

olta

ge (m

V)







Tomicroprocessor

TC1047

3

1 2

VSS

Vout

Vcc = 33V



0025

05075

1125

15175

2

10 35 60 85 110 135

Out

put v

olta

ge (V

)


minus40 minus15

Temperature (∘C)






02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










02468

1012141618202224262830

Days


Min temperature

January February

Tem

pera

ture

(∘C)

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58


HIH-4000


(5V)0V

minusve +veVout






V (ms) = 120596 (rads) sdot 119903 (10)



0102030405060708090

100

05 1 15 2 25 3 35 4

Rela

tive h

umid

ity (

)

Output voltage (V)



0102030405060708090

100

Relat

ive h

umid

ity (

)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58




020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










020406080

100120140160180200

0 025 05 075 1 125 15 175 2 225 25 275 3

Rota

tion

spee

d (H

z)



0123456789

10

Aver

age s

peed

(km

h)

Days

FebruaryJanuary

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











1198671= 0V


1198671= 0V


1198672= 0V


1198672= 0V


1= 0V119867

2= 0V




1198671 (11)



0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0 10 20 30

4050

60

70

80

90

100

110

120

130

140

150160170180190200210

220230

240

250

260

270

280

290

300

310320330

340 350

N

S

EW

Hall sensor 2

Hall sensor 1

Permanent magnet

Direction of

Magnetic fieldlines

rotation

minus

+


H1 gt 0

H2 gt 0

H1 gt 0

H2 lt 0

H1 lt 0

H2 gt 0

H1 lt 0

H2 lt 0

H2

H1120572

minus120572

180 minus 120572

120572 + 180

(H1 gt 0(H1 lt 0

(H1=0

0)(H

1=0

H2lt

H2gt0)

H2 = 0)H2 = 0)

(W1W2)





minus3

minus25

minus2

minus15

minus1

minus05

0

05

1

15

2

25

3minus500

minus400

minus300

minus200

minus100 0

100

200

300

400

500

Output voltage(V)



005

115

225

3

0 30 60 90 120 150 180 210 240 270 300 330 360

Out

put v

olta

ge (V

)


minus3

minus25

minus2

minus15

minus1

minus05






0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

50

100

150

200

250

300

350

Dire

ctio

n (d

eg)

FebruaryJanuary

N

NE

E

SE

S

SW

W

NW

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58





119881light =119881LDR1 + 119881LDR2

2

=119881cc2sdot ((119877LDR1119877LDR1 + 1198771

)+(119877LDR2119877LDR2 + 1198772

))

(12)















1 Lm2= 1mm 997888rarr 100Hz

(14)






R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










R1 = 1kΩ

Vcc = 5V

To microprocessor


LDR1

LDR2

VLDR1




0025

05075

1125

15175

2225

25

Out

put v

olta

ge (V

)

Time

LDR 1LDR 2


100

45

100

54

101

02

101

11

101

20

101

28

101

37

101

45

101

54

102

02

102

11

102

20

102

28

102

37

102

45

102

54



0100200300400500600700800900

Sola

r rad

iatio

n (W

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58







contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












contact


Water sinks

Metal contact



RL100 kΩ

15 120583F

CL

10kΩ

68kΩ

12kΩ

5kΩ

4

5

7

8

1

62

3

10kΩ

Rt = 68kΩ

Ct = 10nF

Vcc

Vcc

Vout

Rs

fi


02468

10121416182022

Aver

age r

ain

(mm

)

FebruaryJanuary

Days1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58











Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Internet

Client VPN server

VPN server

(2) Open TPC socket


(6) Close socket

ACK connection

ACK connection

Data request

Data request

ACK connection

ACK data

ACK data

ACK data

Close connection

Close connection

Close

Remote device

Tunnel VPN

(1) Start device

(2) Open TCP socket





Data server

Data serverBuoy



(5) Read data

(5) Read data






Connection request

Connection request

Connection request



Send data



(a) (b) (c) (d)



0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

20

40

60

80

100

120

Con

sum

ed b

andw

idth

(kbp

s)

Time (s)


0 30 60 90 120 150 180 210 240 270 300 330







Acknowledgment


References























































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation













































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Research Article Oceanographic Multisensor Buoy Based on Low...

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