CN204044143U - A kind of water quality monitoring node based on WSN - Google Patents
A kind of water quality monitoring node based on WSN Download PDFInfo
- Publication number
- CN204044143U CN204044143U CN201420518639.4U CN201420518639U CN204044143U CN 204044143 U CN204044143 U CN 204044143U CN 201420518639 U CN201420518639 U CN 201420518639U CN 204044143 U CN204044143 U CN 204044143U
- Authority
- CN
- China
- Prior art keywords
- sensor
- water quality
- resistance
- quality monitoring
- voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Arrangements For Transmission Of Measured Signals (AREA)
Abstract
The utility model provides a kind of water quality monitoring node based on WSN, and described water quality monitoring node is responsible for the water quality data such as temperature, pH value, dissolved oxygen DO gathering waters to be measured.Water quality monitoring node of the present utility model is to have employed in the important improvement of configuration aspects the structure that sensor is separated with microcontroller chip, pluggable row's pin is adopted both to be combined, the two separable physically and separate configurations, contributes to the maintenance of sensor node and the expansion of function.
Description
Technical field
The utility model relates to water quality monitoring technology, more specifically, relates to a kind of water quality monitoring node based on WSN.
Background technology
Water resource is one of the mankind's important natural resources of depending on for existence and development, and the sustainable use of water resource is the important guarantees of society, sustainable economic development.Pollution in recent years along with water resource is day by day serious, and water quality monitoring is as the basic work in water pollution control work, and for water environment management, pollution source apportionment and environmental planning provide scientific basis, its meaning and function also becomes more important.
Traditional robotization water quality monitoring means have employed wired automatic monitoring system.This system utilizes sensor technology and embedded technology to build a monitoring center and some monitoring sub-stations, can realize the in real time effective of water quality data and automatically gather and transmission, and monitoring center can the data of each monitoring sub-station of real-time query simultaneously.But the transmission of the data of this system needs spider lines, be not suitable for monitor large-area waters, and maintenance cost is too high.
The high speed development of WSN technology and be applied as water quality monitoring and provide new research direction.WSN will have the microsensor node of perception, wireless communication ability and computing power to adopt rule or random fashion to be deployed in guarded region, the distributed network of the ad hoc multihop consisted of communication in a large number.The distributed network of WSN comprises the large element of sensor node, aggregation node and management node three usually.The sensor node be deployed in monitored area forms a monitoring network by Ad hoc mode, the various Monitoring Data that sensor node obtains are focused on aggregation node by certain routing mode, aggregation node by internet or other forwarded data to management node and user terminal.Except gathering physical quantity data, sensor node also needs the function bearing routing node usually, forwards the data that other sensor node needs to send.
The data acquisition network dependence short-distance wireless communication technology of WSN realizes the data transmission between sensor node.At present, the development of various short-distance wireless communication technology is swift and violent, is widely used, comparative maturity have infrared communication (Infrared Data Association, IrDA), bluetooth, Wi-Fi, ZigBee etc.Wherein, ZigBee technology grows up on the basis of IEEE 802.15.4 consensus standard, be the radio network technique of a kind of low-power consumption, low rate, low cost, low complex degree, be highly suitable for building WSN data transmission network, become the first-selection of most WSN system at present.
WSN integrates embedded technology, sensor technology, radio communication and modern network technology, distributed information processing etc., can provide information full and accurate in a large number for user at any time and place with under environment.WSN has that cost is low, networking flexibility, on features such as surrounding enviroment impact are less.Therefore, WSN technology is utilized can to realize the efficient, quick, real-time of water quality and remote monitoring.Therefore, the water quality monitoring system based on WSN becomes a new study hotspot, is with a wide range of applications.
Whole based in the water quality monitoring system of WSN, sensor node is the least work energy unit of responsible water quality data collection, process and transmission, is also the most basic link of whole system.Sensor node should to possess low-power consumption, low cost, small size and strong perception for target.Safeguarding of sensor node has important value with Scalable Performance to realizing above-mentioned target.
In order to ensure that water quality monitoring accurately and reliably, regularly by safeguarding that changing perceptual sensitivity reduces or occur that the sensor of deviation is very important, thus sensor node should possess and is easy to realize above-mentioned maintenance process, and reduces the cost safeguarded.Along with the raising day by day of water quality monitoring demand, system needs often to upgrade adjustment, correspondingly, sensor node should reserve expansion interface, ensure not have an impact to system when changing hardware, under the prerequisite not affecting existing capability, increase new function and application simultaneously, realize the smooth upgrade of system.
Visible, based in the water quality monitoring node of WSN, the hardware configuration that the sensor node of sensor maintenance and expansion is convenient in design is a direction of being improved prior art.
Utility model content
Based on above-mentioned needs of the prior art, the utility model provides a kind of water quality monitoring node based on WSN, which provide a kind of hardware configuration of improvement, the main circuit part that this structure can realize having WSN function is connected with the detachable of sensor assembly, closed the improvement of fastening by this signal wiring, be convenient to the sensor node of sensor maintenance and expansion.
Water quality monitoring node based on WSN described in the utility model is responsible for the water quality data such as temperature, pH value, dissolved oxygen DO gathering waters to be measured.The important improvement of water quality monitoring node of the present utility model is to have employed the structure that sensor is separated with microcontroller chip, sensor and microcontroller chip adopt pluggable row's pin both to be combined, and contribute to the maintenance of sensor node and the expansion of function.
The utility model provides a kind of water quality monitoring node based on WSN, comprising: sensor assembly, microcontroller chip and power module; Described sensor assembly comprises water quality monitoring sensor and Conditioning Circuits of Sensor, the analog signal output sub-connection Conditioning Circuits of Sensor of water quality monitoring sensor; Described microcontroller chip is the main control chip unit adopting Single-Chip Integration SoC structure, and described microcontroller chip comprises processor module and ZigBee wireless communication module; Described processor module comprises CPU element, storage unit, clock unit, hyperchannel AD converter unit, low-voltage monitoring means, timer units and GPIO port; Described ZigBee wireless communication module comprises RF transceiver unit, buffer unit, Power Management Unit, IRQ control module, steering logic unit and GPIO port; Described processor module is connected by spi bus interface with ZigBee wireless communication module; The power input terminal of described power module connecting sensor module and microcontroller chip, to power to sensor assembly and microcontroller chip;
Wherein, described sensor assembly is combined by pluggable row's pin and described microcontroller chip and power module; Further, described water quality monitoring sensor is placed under water and connects described Conditioning Circuits of Sensor by extended line; Described Conditioning Circuits of Sensor and microcontroller chip and power module are arranged in the compartment that floats on the surface.
Preferably, described sensor assembly comprises following at least one sensor: temperature sensor, pH value sensor, dissolved oxygen sensor.
Preferably, described Conditioning Circuits of Sensor comprises multistage operations amplification circuit.
Further preferably, described temperature sensor modulate circuit comprises the sensor measurement electric bridge adopting three-wire system connection to overlap by the first resistance, the second resistance, the 3rd resistance and metal fever resistance; Described multistage operations amplification circuit is two-stage calculation amplification circuit, and wherein the 4th resistance is connected first order operation amplifier integrated circuit with the 5th resistance and controls first order amplification; 6th resistance is connected second level operation amplifier integrated circuit with the 7th resistance and controls second level amplification.
Further preferably, pH sensor modulate circuit comprises two-stage calculation amplification circuit, and the VCC pin of two-stage calculation amplification circuit is connected generating positive and negative voltage respectively with VEE pin.
Further preferably, dissolved oxygen sensor modulate circuit comprises three-stage operational amplification circuit, and wherein the 8th resistance is connected first order operation amplifier integrated circuit with the 9th resistance and controls first order amplification; Tenth resistance is connected second level operation amplifier integrated circuit with the 11 resistance and controls second level amplification; 12 resistance is connected third level operation amplifier integrated circuit with the 13 resistance and controls third level amplification.
Preferably, described power module comprises power-switching circuit and filtering circuit, provides multipath voltage regulation direct current to export, and is respectively used to power to sensor assembly and microcontroller chip; Described power-switching circuit comprises dual channel source dispense switch, the input voltage pin of described dual channel source dispense switch connects direct supply, two-way voltage output pin connects the voltage input pin of forward low dropout voltage regulator, and the voltage output pin of described forward low dropout voltage regulator provides constant voltage DC to export; The voltage input pin of forward low dropout voltage regulator is connected some roads filter capacitor with voltage output pin.
The improvement of the water quality monitoring node based on WSN described in the utility model is: in hardware configuration, have employed the structure that sensor assembly is separated with microcontroller chip, can only upgrade the sensor assembly that misalignment or sensitivity decline in maintenance process, also can the practical function expansion by the sensor assembly in conjunction with newtype.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail:
Fig. 1 is water quality monitoring architectural schematic described in the utility model;
Fig. 2 is water quality monitoring node one-piece construction schematic diagram described in the utility model;
Fig. 3 is temperature sensor modulate circuit structural representation described in the utility model;
Fig. 4 is pH sensor modulate circuit structural representation described in the utility model;
Fig. 5 is dissolved oxygen sensor modulate circuit structural representation described in the utility model;
Fig. 6 is the inner structure block diagram of microcontroller chip described in the utility model;
Fig. 7 is the structural representation of the power module of water quality monitoring node described in the utility model.
Embodiment
The technical solution of the utility model is understood better in order to make those skilled in the art person, and enable above-mentioned purpose of the present utility model, feature and advantage become apparent more, below in conjunction with embodiment and embodiment accompanying drawing, the utility model is described in further detail.
Fig. 1 is the structural representation of the water quality monitoring system based on WSN described in the utility model.This system has three story frame structures of sensor node (node layer)-primary controller (gateway layer)-Surveillance center (server layer).According to this framework, as shown in Figure 1, system is made up of three parts: the remote monitoring center being deployed in the sensor node in waters to be measured, being deployed in the primary controller (gateway) in waters to be measured and disposing on the server.The sensor node dynamic self-organization being deployed in waters to be measured forms monitoring network, can collecting temperature, pH value, one or more water quality datas in dissolved oxygen DO, and carries out the operation such as data fusion and data storage to it, finally data is sent to gateway; Gateway sends to remote monitoring center through GPRS network after having been collected by all water quality datas; Surveillance center classifies to the data received and analyzes, and the polluted water situation exceeding setting threshold value is carried out alarm, for the control of water pollutions provides technical support, remote terminal user can carry out Real-Time Monitoring by the equipment such as mobile phone or PC to waters to be measured.
In the middle of the system of whole WSN, sensor node is minimum functional unit, is also most basic unit, is responsible for the collection of water quality data, process and transmission.Its design should with low-power consumption, low cost, small size and strong perception for target.Sensor node should have following function:
(1) water quality data such as temperature, pH value, dissolved oxygen DO in waters to be measured is gathered: at least integrated temperature sensor, pH sensor and dissolved oxygen sensor on sensor node, measurement index is: temperature 0 ~ 100 DEG C, pH value 0 ~ 14, dissolved oxygen DO 0 ~ 20mg/L.
(2) data prediction and timing transmission: first sensor node carries out correction judgement after collecting water quality data, abandon the data of apparent error, then data are preserved in node according to certain data structure, by the time disposable after certain time interval data to be sent.
(3) Joint Enterprise: sensor node can receive the order that gateway sends, and modifies to configuration parameters such as sample frequency, uplink time interval, emissive powers.
(4) low power consumption wireless network based on Zigbee protocol is set up: after sensor node powers on, automatically can add network, and the role of oneself is set as required for routing node or ordinary node, according to predetermined network protocol transmission data, time idle, enter low-power consumption mode, reduce energy loss.
Sensor node provided by the utility model is in the design process to realize above-mentioned functions and performance requirement for target, emphasis considers the factor of following several respects: first, sensor node is extensively laid among water body in a large number, be subject to environment and the impact of self deterioration factor, be easy to occur sensitivity decrease, measure numerical value malalignment to completely malfunctioning situation, need periodic maintenance, the node not reaching requirement is upgraded, therefore sensor node should have good renewable structure, can realize node maintenance with lower cost.Secondly, sensor node of the present utility model can collecting temperature, pH value, these three kinds of water quality datas of dissolved oxygen DO, but the project will monitored in water quality monitoring also has a lot, as hydraulic pressure, turbidity, conductance etc., fully should reserve expansion interface when design of node, realize general extension ability.3rd, sensor node is often deployed in unattended field, cannot keep electric power supply, therefore adopts battery system to power, and because battery electric quantity is limited, and frequently can not change battery, this just needs design of node efficient energy-saving.4th, sensor node should set up the high data processing of high-level efficiency, low cost and accuracy and node communication mechanism.
Based on above-mentioned mentality of designing, the utility model provides as shown in Figure 2 based on the water quality monitoring node of WSN.The described water quality monitoring node based on WSN comprises: sensor assembly 1, microcontroller chip 2 and power module 3.Described sensor assembly 1 specifically comprises water quality monitoring sensor and Conditioning Circuits of Sensor, described water quality monitoring sensor is used for the water quality parameters such as temperature sensor, pH value, dissolved oxygen DO and generates corresponding induced voltage signal, the induced voltage signal that described Conditioning Circuits of Sensor is used for water quality monitoring sensor generates carries out signal condition and amplification, thus the ultra-weak electronic signal that sensor generates is amplified to electric signal within the scope of 0-3.3V, be supplied to microprocessor chip and carry out AD conversion and follow-up process and communicate.Described microcontroller chip 2 is the main control chip unit adopting Single-Chip Integration (SoC) structure, the functional module of data processing and radio communication is integrated in the middle of chip piece by this chip, improve integrated level, also reduce volume, but correspondingly the functional module performance of data processing is subject to a definite limitation, need data processing and the communication mechanism of improvement.Processor module and ZigBee wireless communication module is integrated with in the middle of described microcontroller chip.Described processor module is used for carrying out AD conversion, process, storage to the induced voltage signal through signal condition and amplification, and carry out data transmit-receive transmission with ZigBee wireless communication module, and it is mutual to perform with WSN network, is core control and the data processing module of sensor node.Described ZigBee wireless communication module is used for the wireless signal transmitting-receiving carrying out data based on IEEE802.15.4 agreement.Described power module 3 is for powering to sensor assembly and microcontroller chip.
Described water quality monitoring sensor is placed under water and connects described Conditioning Circuits of Sensor by extended line; The Conditioning Circuits of Sensor of described sensor assembly and microcontroller chip and power module are all arranged in the compartment that floats on the surface, and each chip and circuit all pass through necessary water-proofing treatment.
The water quality monitoring sensor used in the utility model can comprise: temperature sensor, pH value sensor, dissolved oxygen sensor.
Temperature sensor detects water temperature.Temperature sensor conventional on market has thermopair, thermal resistance and integrated temperature sensor.Wherein, thermal resistance carries out thermometric based on the thermal effect of resistance, namely resistive element resistance variation with temperature and change.Therefore, as long as measure the change in resistance of temperature-sensing thermal resistance, just temperature can be measured.At present, thermal resistance mainly contains metal fever resistance and semiconductor thermistor two class.Wherein, the resistance value of metal fever resistance and temperature generally can represent with following approximate relation, that is: R
t=R
t0[1+ α (t-t
0)], in formula, R
tfor resistance during temperature t, R
t0for temperature t
0(usual t
0=0 DEG C) time corresponding resistance value, α is temperature coefficient.Metal fever resistance is generally applicable to the temperature survey within the scope of-200 ~+500 DEG C, is characterized in measuring accurate, good stability, dependable performance.Current most widely used thermal resistance material is platinum and copper: particularly platinum resistance precision is high, is applicable to neutrality and Oxidant, good stability, and have certain non-linear, more high resistance rate of change is less for temperature.The most frequently used platinum resistance thermometer sensor, of China has R
0=10 Ω, R
0=100 Ω and R
0=1000 Ω etc. are several, and their Graduation Number is respectively Pt10, Pt100, Pt1000.The utility model considers that measuring tempeature scope is little, but requires that measuring accuracy is high, therefore employing measuring accuracy is high, the Pt100 platinum resistance of good stability.Pt100 platinum resistance thermal response time is less than 30s, and minimum placed-depth is more than or equal to 200mm, and allow electric current to be less than 5mA, when changing between 0 ~ 100 DEG C, range of temperature 100 ~ 140 Ω, maximum non-linear deviation is less than 0.5 degree Celsius.
The modulate circuit that Pt100 is conventional has constant current source temperature measurement circuit and bridge-type temperature measurement circuit.The utility model have employed the bridge-type temperature measurement circuit being easy to realize, and circuit theory diagrams are shown in Fig. 3.Pt-R2, Pt-R3, Pt-R4 and Pt100 form sensor measurement electric bridge (wherein Pt-R2=Pt-R4, Pt-R3 is the precision resistance of ± 1%), in sensor access, adopt three-wire system connection to eliminate the resistance interference of sensor two ends wire, in order to ensure the stable of bridge output voltage, bridge input voltage is stablized to 2.5V by TL431.
The temperature sensor modulate circuit that the utility model is applied, except above-mentioned bridge-type temperature measurement circuit, is also amplified by two-stage the voltage signal exported from electric bridge, reoffers to microcontroller chip.As shown in Figure 3, amplifying circuit adopts LM324, LM324 is four high guaily unit integrated circuit, voltage range wide (3.0 ~ 32V), quiescent current is little, operating temperature range wide (-25 ~+85 DEG C), during single power supply, its minimum enlargement factor is one times, maximum amplification 100 times, input end minimum voltage 0.03mV, output maximum voltage is reference voltage.In this circuit, LM324 adopts 5V to power, and in order to prevent the too high nonlinearity erron brought of single-stage enlargement factor, adopt two-stage to amplify, Pt-R7/Pt-R5 controls the first order and amplifies, and Pt-R9/Pt-R10 controls the second level and amplifies.Whole circuit enlargement factor is about (Pt-R7/Pt-R5+1) * (Pt-R9/Pt-R10+1), is generally 30 times.When temperature changes within the scope of 0 ~ 100 DEG C, the voltage after amplification is within 0 ~ 3.3V.
PH value sensor is for detecting the pH value of water body.The measuring method of pH value sensor generally adopts glass electrode method.Potential electrode and reference electrode are packaged together and form pH combination electrode.According to energy this spy (Nernst) equation, pass between the absolute temperature of output electromotive force, fluid to be measured, the pH value of fluid to be measured is E=E0+KT (pHx-pH0), wherein E is for exporting electromotive force, E0 is constant, be correlated with electrode material etc., K is Nernst coefficient, and T is the absolute temperature of testing liquid, pHx is testing liquid pH value, and pH0 is the pH value of damping fluid in combination electrode.What the utility model adopted glass electrode and contrast electrode to combine moulds shell not refilling type combination electrode, pH value determination is carried out by the hydrogen ion activity measured in water, measurement range 0 ~ 14, measuring tempeature 0 ~ 60 DEG C, the response time is less than 1 minute, voltage output range-414.12 ~+414.12mV, linear relationship is met between voltage and pH value, coefficient is 59.16, namely often changes 1pH, change in voltage 59.16mV.
The voltage range of pH sensor is-414.12 ~+414.12mV, need equally amplifying circuit signal is amplified after just can export to A/D module and carry out digital-to-analog conversion, the synthermal Conditioning Circuits of Sensor of its amplification principle is similar, adopts LM324 chip to carry out voltage amplification, as shown in Figure 4.Because pH sensor output voltage has dividing of generating positive and negative voltage, namely positive voltage is exported when fluid to be measured is acid, for exporting negative voltage during alkalescence, therefore, LM324 adopts dual power supply, VCC pin is positive voltage VCC, VEE pin is negative voltage-VCC, and enlargement factor is-1 ~-100 times and 1 ~ 100 times.The enlargement factor of whole amplifying circuit is (DR21/DR20+1) * (DR24/DR23+1).
Dissolved oxygen DO (Dissolved Oxygen, DO) refers to the oxygen of the molecular state that is dissolved in the water, the O2 namely in water.Dissolved oxygen DO is aquatic organism existence conditio sune qua non, when dissolved oxygen DO is lower than 4mg/L, will cause fish death by suffocation, for the mankind, healthy drink content of oxygen dissolved in water and must not be less than 6mg/L.Therefore, the measurement of Dissolved Oxygen in Water content, significant for water quality monitoring.Dissolved oxygen sensor make use of electrochemical principle, when the metal that any two kinds of active degree are not identical is put in same electrolyte solution, a primary element can be formed respectively, its normal potential of metal more active in two electrodes is lower, become the negative pole of primary element, the positive pole of what another normal electrode was higher become primary element.Be present between positive and negative electrode is electrolytic solution by ionic conduction.Negative electrode release ion, anode receives ion and forms electric current, and in electrode reaction, the transfer amount of electronics is directly proportional to the dissolved oxygen content that participation is reacted, and namely output current is directly proportional to oxygen concentration in medium.Dissolved oxygen electrode is divided into galvanic cell type and polarogram type.Two kinds of sensors have a thin semipermeability film, launch on a sensor, gas can be allowed to enter by while electrode and external environment condition isolation.When operating, the bottom of sensor can be full of electrolytic solution containing a small amount of surfactant to improve wettability effect, because electrolytic solution participates in reaction in measuring process, therefore, needs periodic replacement electrolytic solution.Because the electrode material used is different, polarogram type electrode needs the polarizing voltage of additional 0.6 ~ 0.8V.The advantage of galvanic cell type electrode is that the response time is fast, and shortcoming does not have polarogram type electrode long in the life-span, and the advantage of polarogram type electrode is long service life, and shortcoming is the needs preheating times of 5 ~ 15 minutes.The utility model adopts the polarographic dissolved oxygen sensor that cost performance is higher, and measurement range 0 ~ 20mg/L, temperature applicable range 0 ~ 40 DEG C, offset output is less than 0.3mV, and the response time is less than 20s, voltage output range 0.3 ~ 55mV.
The synthermal Conditioning Circuits of Sensor of dissolved oxygen sensor modulate circuit principle of work is similar, is also to adopt LM324 to amplify voltage signal, and its modulate circuit is shown in Fig. 5.Dissolved oxygen sensor modulate circuit exports to AD pin after the feeble signal of dissolved oxygen sensor being amplified by three grades.Wherein, R4/R5 controls the first order and amplifies, and R8/R9 controls the second level and amplifies, and R10/R11 controls the third level and amplifies, and enlargement factor is (R4/R5+1) * (R8/R9+1) * (R10/R11+1).
The utility model have employed the chip solution of 8 or 16 Single-Chip Integration (SoC) structures as described microcontroller chip, processor module MCU and ZigBee wireless communication module are integrated in same chip by this main control chip solution, not only increase integrated level, also make chip volume less, but define the processing power of MCU.Described processor module is used for carrying out AD conversion, process, storage to the induced voltage signal through signal condition and amplification, and carries out data transmit-receive transmission with ZigBee wireless communication module, and performs and WSN network mutual; Described ZigBee wireless communication module is used for the wireless signal transmitting-receiving carrying out data based on IEEE802.15.4 agreement.
Fig. 6 shows the inner structure block diagram of microcontroller chip.Described processor module MCU comprises: CPU element, can perform data processing under the highest system frequency of 40MHZ; Storage unit, comprises ram cell and FLASH unit; Internal clocking module; Hyperchannel AD converter unit ADC, provides 8 path 10 position analog to digital conversion; Low-voltage monitoring means; 16 bit timing device unit; 32 road GPIO ports; Two-way asynchronous serial communication interface 2xSCI; Iic bus; Background debugging module; And SPI internal bus interface.Described ZigBee wireless communication module 802.15.4 Modem comprises: RF transceiver unit, and this unit specifically comprises transmit-receive switch, frequency generator, simulating signal receiver, simulating signal transmitter and digital transceiver unit; Buffer unit RAM, provides transceiving data buffer memory; RAM moderator; Power Management Unit and voltage regulator; Event timer; Digital control logic; Multichannel GPIO port; SPI internal bus interface, described processor module and ZigBee wireless communication module are transmitted by spi bus Interface realization data therebetween; ZigBee wireless communication module also has IRQ control module, thus ZigBee wireless communication module realizes the associated treatment with processor module based on sending IRQ interrupt request.
Fig. 7 is the structural representation of the power module of water quality monitoring node.Power module is primarily of power-switching circuit and filtering circuit composition, and as shown in Figure 7, this module has two kinds of output voltage 5V and 3.3V.Wherein 5V is that sensor assembly is powered, and 3.3V provides reference voltage for processor module etc.VCC_IN represents input voltage, 5V DC power supply can be used in the debug phase, 3.7V lithium battery power supply is then used after node deployment, the microcontroller chip inside adopted due to the utility model containing mu balanced circuit, therefore VCC_IN after filtering after can power directly to microcontroller chip.In Fig. 7, MIC2026 is dual channel source dispense switch, provides two-way voltage to export, and allows electric current 500mA, and after node starts, enable ENA then OUTA provides 5V voltage to export; Enable ENB then OUTB provides 5V voltage to export, then can produce the burning voltage output of 3.3V through AMS1117-3.3 chip.AMS1117-3.3 is a forward low dropout voltage regulator, and volume is little, low in energy consumption.Meanwhile, in order to improve the anti-interference of power supply, installed filter capacitor around power supply, this design effectively can reduce the impact of power-supply fluctuation on system.
Introduce the course of work of water quality monitoring node described in the utility model below.After water quality monitoring node starts, first carry out system initialization.System initialization module is the core of system, and water quality monitoring node needed to carry out initialization to whole system before starting working.System initialization mainly comprises the initialization of system clock initialization, timer initialization, AD initialization, serial ports initialization, Flash initialization, I/O port initialization and data buffer.After initialization, system enters endless loop and performs corresponding power function, completes water quality data collection, transmission.
Main in initialization procedure arranges as follows: (1) closes house dog, prevents chip from resetting because of counter overflow.Generally close house dog in the software debugging stage, and after system commencement of commercial operation, open house dog, increase system stability.(2) configure ZigBee wireless communication module, the default transmit power arranging this wireless module is total power, and default communication channel is channel 10, CLKO output clock is 8MHz or 4MHz.(3) adopt CLKO as the external clock reference of processor module MCU, after frequency division frequency multiplication, system clock has 8MHz and 40MHz two kinds selection, considers the power problems of system therefore the system clock of employing 8MHz.(4) arranging timer 1 break period is 10 milliseconds.(5) initialization serial ports 1, arranging baud rate is 9600.
After completing initial work, node enters and adds network development process.If do not have network can for adding, the networking of node waiting system, if there is network can for adding, node selects suitable network to add after carrying out a series of checking.The network of sensor node composition can be divided into terminal node, cluster head node and gateway node.
The central task of water quality monitoring node carries out collection and the transmission of water quality data, time interval that default AD gathers, when being in the time period that AD gathers, the AD pin of microcontroller chip gathers the voltage signal after each sensor assembly conditioning and sends to cluster head node, cluster head node receives the data that each terminal node sends, and disposablely after data fusion is sent to gateway node.The voltage range of AD pin collection is 0 ~ 3.3V, and adopt 10 sampling precisions herein, after AD conversion, numerical range is 0 ~ 1023.In measuring process, generally all having from system itself or extraneous noise, for increasing the accuracy of measurement data, adding filter herein.Program filtering, namely by certain calculating and judgement, reduces the ratio of undesired signal in measured signal in a program, and classical program filtering method has weighted filtering, medium filtering and mean filter etc.The method design filter adopting medium filtering and mean filter to combine herein, first enters the process of slotting several times mean filter, and carries out medium filtering process to the intermediate result of several times mean filter process.Such as,, first the A/D module of microcontroller chip is carried out 20 AD and is gathered, and averages after the AD value collected being sued for peace again, so just obtain the result after mean filter, the intermediate value of getting in the result after three mean filters sends as net result or preserves.
The radio communication of sensor node depends on the integrated ZigBee wireless communication module of microcontroller chip, and being communicated by SPI between ZigBee wireless communication module with processor module MCU realizes the transmitting-receiving of data.Define the data-transmission mode between two kinds of ZigBee wireless communication modules and processor module MCU: flow (Stream) pattern and bag (Packet) pattern.In stream mode, data send or receive is all word for word process, and the data often receiving or send a word all can trigger once interrupts.And in pack mode, the data that first will send are disposable to be stored in and to send in buffer zone, and then disposablely to send; During data receiver, take over party is the whole packet of buffer memory in data buffer first, then triggered interrupts notice MCU reads.Under pack mode, the transmitting-receiving of data needs to wait until that all data just can be carried out all in the buffer, this can bring certain delay, but which can not frequent triggered interrupts, reduce the resource occupation to MCU, and be convenient to the disposable process of data, therefore, pack mode is adopted when data are transmitted herein.
1. wireless data sends
Under pack mode, the process of transmitting of data is:
(1) first judge whether ZigBee wireless communication module is in idle pulley, if then enter next step, then stop if not sending and returning error message to upper strata.Because idle pulley is the originate mode entering other patterns, can not directly change between other patterns.
(2) MCU loads outgoing data length, then writes affairs by SPI circulation and is loaded in transmission data buffer (TX RAM) by outgoing data.
(3) MCU drags down sending/receiving enable (RXTXEN) pin, and ZigBee wireless communication module is transformed into sending mode from idle pulley.
(4) MCU draws high sending/receiving enable pin and keeps high level, starts data transmission procedure.
(5) complete after data send and produce an IRQ interruption, ZigBee wireless communication module returning to idle mode.
(6) enter IRQ interrupt processing function and complete subsequent action, return data sends success message.
2. receive data by wireless
Under pack mode, the receiving course of data is:
(1) MCU drags down sending/receiving enable pin, and arranges the Control_A register in ZigBee wireless communication module, allows receive interruption request.
(2) MCU arranges Control_A register, and ZigBee wireless communication module is switched to receiving mode from idle pulley, if Modem original state is not idle pulley, then and terminating reception process, and return error message.
(3) MCU draws high sending/receiving enable pin and keeps high level, starts DRP data reception process.
(4) after data receiver completes, ZigBee wireless communication module can carry out a series of validity checking, confirms that the errorless backward MCU of data receiver sends an IRQ interrupt request.
(5) MCU accepts IRQ and interrupts and respond, and takes out packet and also carries out subsequent treatment, return reception success message from reception data buffer (RX RAM).
After ZigBee wireless communication module completes a certain operation (as transmission, reception etc.), can drag down the IRQ interrupt pin of MCU, send an IRQ interrupt request to MCU, MCU accepts and responds this interruption, enters IRQ interrupt processing function and carries out state processing.After entering IRQ interrupt processing function, MCU reads IRQ status register, the type information producing and interrupt is saved in this register, owing to may occur that multiple IRQ interrupts situation about producing simultaneously, for preventing omitting, after running through status register information, judge whether IRQ pin is dragged down again at once, if then again read IRQ status register, so circulation is not until interrupt producing.After running through the content of status register, perform corresponding operation according to different interrupt types.
The energy ezpenditure reducing node is significant for maintenance node life cycle.The energy ezpenditure of ZigBee wireless communication module accounts for and consumes more than 80% of gross energy, even if because node also needs to intercept wireless channel, consumed energy at one's leisure.Start with from the following aspect herein carry out low power dissipation design to reduce the unnecessary energy consumption of node:
(1) traffic is reduced.Devise efficient communication protocol herein, reduce frame head and verification expense in communication process, and adopt Data fusion technique to reduce data traffic.
(2) dormancy mechanism is increased.During node transmission data, energy consumption is maximum, close with idle condition energy consumption in reception, and dormant state energy consumption is minimum, so allow node enter dormant state in the time period of node free time.
ZigBee wireless communication module has activity pattern and low-power consumption mode two kinds of operational modes, and wherein activity pattern comprises free time (Idle) pattern, reception (RX) pattern, transmission (TX) pattern three kinds; Low-power consumption mode comprises closedown (Off) pattern, dormancy (Hibemate) pattern and (Doze) pattern three kinds of catnaping.Under activity pattern, be defaulted as idle pulley, it is also the transfer mode receiving and send two kinds of patterns, namely receives and sends between two kinds of patterns and can not directly change, after needing first to return to idle pulley, just can enter another kind of pattern.Under low-power consumption mode, " shut " mode" is least in power-consuming, and working current is 0.2 μ A; Secondly be park mode, working current is 1.0 μ A; Mode power consumption of catnaping is the highest, and working current is 35 μ A, and under low-power consumption mode, most of hardware module all can quit work.What the technical solution of the utility model was selected is Doze pattern, and the sharpest edges selecting Doze pattern are that the release time that it exits low-power consumption mode is very short, about 0.3ms.
MCU low-power consumption mode has Stop1, Stop2, Stop3 isotype.For MCU Stop1 pattern (working current 25nA) though least in power-consuming it needs external interrupt that (power up interrupt) could recover, and all registers and RAM data can be lost, therefore the utility model selection can pass through the Stop2 pattern that real-time clock interrupt (RTI) wakes up, wakes MCU up by RTI.RTI is when using internal clock source, and it produces the maximum cycle interrupted is 1024ms.
In sum, the improvement of the water quality monitoring node based on WSN described in the utility model is: in hardware configuration, have employed the structure that sensor assembly is separated with microcontroller chip, can only upgrade the sensor assembly that misalignment or sensitivity decline in maintenance process, also can the practical function expansion by the sensor assembly in conjunction with newtype.Microcontroller chip is integrated with data sampling and processing and based on Zigbee protocol wireless receiving and dispatching, have excellent data processing mechanism and communication mechanism, the sensitivity of monitoring of can increasing water quality and degree of accuracy, reduce node power consumption, increase the service life.
The above, be only embodiment of the present utility model, and the utility model can also be applied in miscellaneous equipment; Size in more than describing and quantity are all only informative, and those skilled in the art can select suitable application size according to actual needs, and do not depart from scope of the present utility model.Protection domain of the present utility model is not limited thereto, and is anyly familiar with those skilled in the art in the technical scope that the utility model discloses, the change that can expect easily or replacement, all should be encompassed within protection domain of the present utility model.Therefore, the protection domain that protection domain of the present utility model should define with claim is as the criterion.
Claims (7)
1. based on a water quality monitoring node of WSN, it is characterized in that, comprising: sensor assembly, microcontroller chip and power module; Described sensor assembly comprises water quality monitoring sensor and Conditioning Circuits of Sensor, the analog signal output sub-connection Conditioning Circuits of Sensor of water quality monitoring sensor; Described microcontroller chip is the main control chip unit adopting Single-Chip Integration SoC structure, and described microcontroller chip comprises processor module and ZigBee wireless communication module; Described processor module comprises CPU element, storage unit, clock unit, hyperchannel AD converter unit, low-voltage monitoring means, timer units and GPIO port; Described ZigBee wireless communication module comprises RF transceiver unit, buffer unit, Power Management Unit, IRQ control module, steering logic unit and GPIO port; Described processor module is connected by spi bus interface with ZigBee wireless communication module; The power input terminal of described power module connecting sensor module and microcontroller chip, to power to sensor assembly and microcontroller chip;
Wherein, described sensor assembly is combined by pluggable row's pin and described microcontroller chip and power module; Further, described water quality monitoring sensor is placed under water and connects described Conditioning Circuits of Sensor by extended line; Described Conditioning Circuits of Sensor and microcontroller chip and power module are arranged in the compartment that floats on the surface.
2. water quality monitoring node according to claim 1, is characterized in that, described sensor assembly comprises following at least one sensor: temperature sensor, pH value sensor, dissolved oxygen sensor.
3. water quality monitoring node according to claim 2, is characterized in that, described Conditioning Circuits of Sensor comprises multistage operations amplification circuit.
4. water quality monitoring node according to claim 3, is characterized in that, described temperature sensor modulate circuit comprises the sensor measurement electric bridge adopting three-wire system connection to overlap by the first resistance, the second resistance, the 3rd resistance and metal fever resistance; Described multistage operations amplification circuit is two-stage calculation amplification circuit, and wherein the 4th resistance is connected first order operation amplifier integrated circuit with the 5th resistance and controls first order amplification; 6th resistance is connected second level operation amplifier integrated circuit with the 7th resistance and controls second level amplification.
5. water quality monitoring node according to claim 3, is characterized in that, pH sensor modulate circuit comprises two-stage calculation amplification circuit, and the VCC pin of two-stage calculation amplification circuit is connected generating positive and negative voltage respectively with VEE pin.
6. water quality monitoring node according to claim 3, is characterized in that, dissolved oxygen sensor modulate circuit comprises three-stage operational amplification circuit, and wherein the 8th resistance is connected first order operation amplifier integrated circuit with the 9th resistance and controls first order amplification; Tenth resistance is connected second level operation amplifier integrated circuit with the 11 resistance and controls second level amplification; 12 resistance is connected third level operation amplifier integrated circuit with the 13 resistance and controls third level amplification.
7. water quality monitoring node according to claim 1, is characterized in that, described power module comprises power-switching circuit and filtering circuit, provides multipath voltage regulation direct current to export, and is respectively used to power to sensor assembly and microcontroller chip; Described power-switching circuit comprises dual channel source dispense switch, the input voltage pin of described dual channel source dispense switch connects direct supply, two-way voltage output pin connects the voltage input pin of forward low dropout voltage regulator, and the voltage output pin of described forward low dropout voltage regulator provides constant voltage DC to export; The voltage input pin of forward low dropout voltage regulator is connected some roads filter capacitor with voltage output pin.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420518639.4U CN204044143U (en) | 2014-09-10 | 2014-09-10 | A kind of water quality monitoring node based on WSN |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420518639.4U CN204044143U (en) | 2014-09-10 | 2014-09-10 | A kind of water quality monitoring node based on WSN |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204044143U true CN204044143U (en) | 2014-12-24 |
Family
ID=52244793
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420518639.4U Expired - Fee Related CN204044143U (en) | 2014-09-10 | 2014-09-10 | A kind of water quality monitoring node based on WSN |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204044143U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104181280A (en) * | 2014-09-10 | 2014-12-03 | 苏州大学 | Water quality monitoring node based on WSN |
| CN106373361A (en) * | 2016-08-31 | 2017-02-01 | 北京浩坤科技有限公司 | Wireless collection and transmission device and method |
| CN106556880A (en) * | 2016-11-23 | 2017-04-05 | 苏州大学 | A kind of weather monitoring sensor node based on ZigBee |
-
2014
- 2014-09-10 CN CN201420518639.4U patent/CN204044143U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104181280A (en) * | 2014-09-10 | 2014-12-03 | 苏州大学 | Water quality monitoring node based on WSN |
| CN104181280B (en) * | 2014-09-10 | 2016-05-25 | 苏州大学 | A kind of water quality monitoring node based on WSN |
| CN106373361A (en) * | 2016-08-31 | 2017-02-01 | 北京浩坤科技有限公司 | Wireless collection and transmission device and method |
| CN106556880A (en) * | 2016-11-23 | 2017-04-05 | 苏州大学 | A kind of weather monitoring sensor node based on ZigBee |
| CN106556880B (en) * | 2016-11-23 | 2019-12-27 | 苏州大学 | Meteorological monitoring sensor node based on zigBee |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104181280B (en) | A kind of water quality monitoring node based on WSN | |
| CN103702444B (en) | Wireless sensor system applied in forest fire prevention | |
| CN204313879U (en) | Aquaculture water quality monitoring system | |
| CN204044143U (en) | A kind of water quality monitoring node based on WSN | |
| CN201903403U (en) | Industrial wireless temperature transmitter | |
| CN203299198U (en) | Soil environment monitoring data collection terminal based on SDI-12 bus | |
| CN106793020A (en) | A kind of low-consumption wireless ad-hoc network kilowatt meter reading-out system | |
| Jin-feng et al. | A Low-cost Wireless Water Quality Auto-monitoring System. | |
| Visconti et al. | Solar Powered WSN for monitoring environment and soil parameters by specific app for mobile devices usable for early flood prediction or water savings | |
| CN103077594A (en) | ZigBee-based wind power plant wireless data acquisition system | |
| CN210271209U (en) | Valve control system based on LoRa wireless communication | |
| CN107632131A (en) | A kind of energy-saving water quality monitoring system based on Zigbee | |
| CN105352020A (en) | Active energy-saving management method | |
| CN106338346A (en) | Wireless sensor network node for temperature monitoring of electrical equipment | |
| CN201707145U (en) | High-precision thermocouple wireless temperature sensor based on wireless sensor network | |
| Jiang et al. | A wireless computational platform for distributed computing based traffic monitoring involving mixed eulerian-lagrangian sensing | |
| Ma et al. | Agricultural environment information collection system based on wireless sensor network | |
| CN104501869A (en) | Aquaculture water quality monitoring system | |
| CN207197567U (en) | Forest fire protection well based on GPRS and single-chip microcomputer remotely monitors transmitting device | |
| CN206212287U (en) | A kind of low-consumption wireless ad-hoc network kilowatt meter reading-out system | |
| CN102573118A (en) | Multi-parameter monitoring using wireless sensor node with self-triggering function | |
| CN206019707U (en) | A kind of Multi-functional data collector based on cellular network | |
| CN204559893U (en) | Wireless communication device, table meter inquiry unit and table meter inquiry system | |
| Sun et al. | A Chain-type Wireless Sensor Network in Greenhouse Agriculture. | |
| CN113259885A (en) | Monitoring data acquisition control system based on Internet of things |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20141224 Termination date: 20170910 |