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A wireless design of low-cost irrigation system usingZigBee technology

Yiming Zhou, Xianglong Yang, Liren Wang, Yibin YingSchool of Biosystems Engineering and Food Science, Zhejiang University

Hangzhou, Chinae-mail: benton.zym@tom.com; xlyang@zju.edu.cn; wanglr@zucc.edu.cn; ybying@zju.edu.cn

AbstractAt present, labor-saving and water-saving technology

is a key issue in irrigation. A wireless solution for intelligent field

irrigation system dedicated to Jew's-ear planting in Lishui,

Zhejiang, China, based on ZigBee technology was proposed in

this paper. Instead of conventional wired connection, the wireless

design made the system easy installation and maintenance. The

hardware architecture and software algorithm of wireless

sensor/actuator node and portable controller, acting as the enddevice and coordinator in ZigBee wireless sensor network

respectively, were elaborated in detail. The performance of the

whole system was evaluated in the end. The long-time smooth

and proper running of the system in the field proved its high

reliability and practicability. As an explorative application of

wireless sensor network in irrigation management, this paper

offered a methodology to establish large-scale remote intelligent

irrigation system.

Keywords- Irrigation; Wireless Sensor Network; ZigBee; Low-

cost

I. INTRODUCTION

People now are working actively at intelligent irrigationsystems because their advantages of labor-saving and water-saving [1-3]. Wireless technology, known for its easyinstallation and maintenance, is thought preponderant todevelop automatic irrigation network and becoming a hotresearch. Shocket al. (1999) used radio transmission for soilmoisture data from data loggers to a central computer loggingsite [4]. Valente et al. (2007) explored a grid of self-poweredmulti-functional probes (MFPz) for small-scale measurementsof different soil properties, as part of a wireless sensor network(WSN) [5]. Zhao et al. (2007) designed an irrigation system forcity greenbelt adopting moisture sensor, wirelesscommunication and RS-485 bus to achieve remote control anddistributed control [6]. Cao et al. (2005) reported a dataacquisition and irrigation control system using nRF903 single

chip RF transceiver [7]. A wireless automatic control systemfor well irrigation was developed by Qi et al. (2005) to realizereasonable utilization of ground water [8]. Kim et al. (2008)presented an integrated distributed wireless sensor network thatutilizes Bluetooth technology for sensor-based variable rateirrigation systems [9].

However, some researchers didnt have fully integrated thesystem [4,5,10] and the system [6], actually was not totallyconfigured by wireless module because RS485 bus was alsoused. Cao et al. (2005) didnt mention the power design andmanagement of wireless sensor which is important in wireless

application [7]. Although power shortages and radio rangewere improved in the wireless distributed system [9], thesystem cost was a little high. Besides, the in-field wirelessmonitoring and control system was not a real WSN withnetwork self-forming and self-healing.

As an example of wireless irrigation system, this paper

developed a design dedicated to Jews ear planting in Lishuiregion, Zhejiang province in China using ZigBee technologyfeaturing low power, low-cost and easy employment.

II. BACKGROUND

With the rapid development of agriculture in China, manyautomatic technologies have been introduced into agriculturalproductions in the research institutions and national agriculturalparks. However, the common farmers, occupying 64 percent ofthe population, are still using traditional tools because of theirlow education level and the high cost of advanced instruments.Lishui, which is generally accepted as the place where wasoriginated the technology of mushroom in the world, is thebiggest producing area of the edible fungus in China, and the

output of the edible fungus accounts for about 45 percent in thecountry. Jews ear is a very popular variety of the ediblefungus. The key factor affecting Jews ear planting lies inirrigation which up to now mainly depends on manual workand thus, with such low efficiency, badly restricts the ediblefungus production. So, there are now pressing needs forintelligent irrigation system with low-cost, easy operation andhigh reliability.

III. METHOD

We explored an economical automatic irrigation systembased on wireless sensor network for Jews ear planting. WhileWSN dispenses with the substantial costs of wiring, the ZigBeeWSN technologies are most suitable for agricultural

application comparing with Wi-Fi and Bluetooth, which workat similar frequencies as ZigBee [11]. We have successfullyapplied the ZigBee wireless technology to greenhousemanagement in our previous researches [11-12]. Now we arefocusing on the study of its application to intelligent irrigation.

A. Application EnvironmentThe farmers plots for planting Jews ear usually spread

from 2000 m2 to 7000 m2. In such a planting and irrigation

section, only one sensor node is needed to measure the airtemperature and humidity. However, numbers of wireless

2009 International Conference on Networks Security, Wireless Communications and Trusted Computing

978-0-7695-3610-1/09 $25.00 2009 IEEE

DOI 10.1109/NSWCTC.2009.231

572

2009 International Conference on Networks Security, Wireless Communications and Trusted Computing

978-0-7695-3610-1/09 $25.00 2009 IEEE

DOI 10.1109/NSWCTC.2009.231

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actuator nodes are required to control the pumps andelectromagnetic valves according to the acreage of irrigationsection. They act the same role as end devices in wirelesssensor network.

B. Solution OverviewA practical system layout of in-field WSN for one irrigation

section is illustrated in Fig. 1.

Figure 1. Conceptual system layout of wireless sensor network for fieldirrigation.

The system consists of a portable controller, a wirelesssensor node, a weather station and several wireless actuators.The sensor node collects the temperature and air humidityparameters in its section, whereas the nearby weather stationmonitors the meteorological information indicating if it rains.All the sensory data are wirelessly sent to the portablecontroller. The in-field actuator nodes are used to control thepump and electromagnetic valves when receive the controlcommands wirelessly transmitted from the portable controller.Both sensor node and actuator node serve as end devices in thewireless network, composing the WSN together with the

portable controller which acts as the coordinator in ZigBeeprotocol to build and maintain the wireless sensor network andmeanwhile manage the irrigation system. Because the ZigBeeWSN is self-forming and self-healing, the ad-hoc irrigationsystem allows user to add or decrease the number of enddevices (sensor nodes and actuator nodes) to meet the large-scale application. If routers are applied, the mesh irrigationnetwork connecting several sections can be configured forremote intelligent irrigating. Expert irrigation strategies can beapplied by connecting the portable controller to computerthrough RS232 if needed.

C. Hardware DesignA single chip JN5121 (JENNIC Ltd, UK) was selected as

the microcontroller for all the nodes because of its highintegration and low cost shown in Fig. 2(a). SMA-connectorantenna was connected to the built-in transceiver through abalun. The wireless sensor node mainly contained a relativehumidity and temperature multi-sensor SHT1x (SENSIRION,Switzerland) to monitor the field environment (see Fig. 2(b))and was powered by batteries. Similar to the sensor node,wireless actuator node connected the actuator driving circuitsto the JN5121 module. In our system, six output channels were

designed on a wireless node to control the pump andelectromagnetic valves (see Fig. 2(c)). Fig. 2 (d) showed thephoto of the portable controller, which contained a LCD andfour buttons for displaying, settings and manual operations.The controller was mainly powered by mains power, andallowed to be powered by onboard batteries as well foremergent use.

D. Nodes Software SystemThe ZigBee specifications define three networking

topologies suitable for various applications. Star networks arecommon and provide for very long battery life operation.Mesh, or peer-to-peer, networks enable high levels ofreliability and scalability by providing more than one paththrough the network. Tree networks combine the benefits ofboth for high levels of reliability and support for battery-powered nodes.

Our irrigation system was based on the star network. Thesoftware algorithms of the three kinds of nodes are shown inFig. 3. Once the coordinator (portable controller) started, itcreated its personal area network (PAN) and allowed the end

devices (sensor actuator nodes) to join the network. After thewireless sensor network formed, it received the sensor data anddisplayed them on the LCD. Irrigation commands could be sentto wireless actuator node determined by the expert strategies.Manual operation was also accessible to the users by pressingthe buttons. The application puts the nodes into doze modewhenever possible to save energy.

Start

Initialization

Create PAN

End Devices

Connect Request

Assign Network

Address

Allow

Connect?

Receive Sensor

Data

Data Process

Need

Irrigate?

Send

Command

Display on LCD

Start

Join Request

Destination

PAN Found?

Connect

Success?

Read Sensors

Send data

Sleep

Start

Join Request

Destination

PAN Found?

Connect

Success?

Sleep

Receive

Command?

Implement

N

Y

Y

N

N

Y

N

Y

(a)

(b) (c)

Figure 3. Program algorithm flowchart of portable controller (a), wirelesssensor node (b) and wireless actuator node (c)

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IV. PERFORMANCES

A. Node Power ConsumptionThe power consumption determines the service life of those

battery-powered nodes working in the field. Since the portablecontroller in our system can be powered by external powersupply and the wireless actuator node are mostly in sleep

mode, so only the power consumption of the sensor node wasdiscussed below [11], including current consumption ofJN5121 [13] and the power consumption of sensors on board.

The sensor node in the enabled wireless networkcontinuously performed the same actions as follow accordingto Fig. 3(b). We set the circulation time of the sensor node for10 seconds in our system. The electrical charge value of eachphase and the sensor on board are listed in table 1. The averagecurrent drawn by this application can be calculated by addingthe electrical charge consumed during each phase and dividingby the total cycle time (10 seconds), that is approximately68.7A. The node should therefore be capable for about 15months when powered by two 750mAh batteries (AAA, 1.5v).That means people do not need to replace the batteries for the

sensor node in 2 years.

TABLE I. THE ELECTRICAL CHARGE VALUE CONSUMED DURING EACHPHASE

Phase Charge (C)

Wake from sleep 551.7

Read sensors 45

Perform CCA 18.56

Transmit data 30.976

Sleep 34.762

Sensor on Board 5.749

Total 686.747

B. Communication RangeAccording to the growing environment of Jews ear, we

evaluated the communication range through packet error rate(PER) testing using portable controller and wireless sensornode as the master module and slave module respectively. Thetest was carried out in the open air and 1m above the groundwithout barrier between the devices. The sensor node sent10000 frames to portable controller via the RF link in differentdistance and the PER was checked for the valid communicationrange which turned to be up to 400 meters. The test result wasshown in Fig. 4.

0

20

40

60

80

100

75 125 175 225 275 325 375 425

Distance(m)

PER(%)

Figure 4. The packet error rate in different distance

C. System CostThe irrigation system is developed with module design

which helped to reduce the cost. The wireless sensor node andactuator node was about 30 US dollars and the portablecontroller was around $100. The total cost to build up awireless field irrigation system depended on the planting area,and for a case of 5000m2, it was approximately $400 in termsof hardware cost.

V. CONCLUSION

Efficient irrigation management is a major concern in manyplanting systems. In this study, we presented a wirelesssolution of in-field irrigation system based on ZigBeetechnology which allowed farmers to maximize theirproductivity while saving labour force. This paper showed indetails of the design of the hardware architecture, the softwarealgorithm applied for the field irrigating management. Theperformance of the whole system proved its high reliability.The practicability and low-cost made the system easilyaccepted by the common users in China. Potential applications

of this system can be extended to environmental monitoring,precision agriculture, and facility automation by littlemodifications. People can also link several such star irrigationnetworks through adding wireless routers to achieve large-scaleremote irrigation application.

REFERENCES

[1] D. Selvath, S. Salivahanan, G. Indumathi, K.R. Vijay Kumar, S.Thamaraiselvi, Fuzzy logic based intelligent control for irrigationsystem. IETE Technical Review (Institution of Electronics andTelecommunication Engineers, India), vol. 20, May/June 2003, pp.199-203.

[2] Y. Liu, Z.H. Ren, D.M. Li, X.K. Tian, Z.N. Lu, The research ofprecision irrigation decision support system based on genetic algorithm.Proc. 2006 Int. Conf. Machine Learning and Cybernetics(ICMLC 06),Aug. 2006, pp. 3123-3127, doi: 10.1109/ICMLC.2006.258403.

[3] S. Khan, M.M. Hafeez, S. Rana, S. Mushtaq, Enhancing waterproductivity at the irrigation system level: A geospatial hydrologyapplication in the Yellow River Basin, Journal of Arid Environments,vol. 72, June 2008, pp.1046-1063, doi:10.1016/j.jaridenv.2007.11.011.

[4] C. C. Shock, R. J. David, C. A. Shock, C. A. Kimberling, Innovative,automatic, low-cost reading of Watermark soil moisture sensors,Proceedings of the International Irrigation Show, Nov. 1999, pp.147152.

[5] A. Valente, R. Morais, C. Serodio, P. Mestre, S. Pinto, M. Cabral, AZigBee Sensor Element for Distributed Monitoring of Soil Parameters in

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Environmental Monitoring, 2007 IEEE SENSORS, Oct. 2007, pp.135-138.

[6] Y.D. Zhao, C.X. Bai, B. Zhao, An Automatic Control System ofPrecision Irrigation for City Greenbelt, Proc. 2nd IEEE Conference onIndustrial Electronics and Applications(ICIEA 07), May 2007, pp. 2013 2017, doi:10.1109/ICIEA.2007.4318763.

[7] C.M. Cao, P. Xia, Z.Q. Zhu, Application of wireless data transmissionto the automatic control of water saving irrigation, Transactions of The

Chinese Society of Agricultural Engineering, vol. 21, April 2007,pp.127-130(in Chinese).

[8] X.B. Qi, S.G. Gao, H.F. Zhao, X.Y. Fan, Wireless Automatic ControlSystem for Well Irrigation Area in North China, Journal of HydraulicEngineering, vol. 36, Feb. 2005, pp.232-237(in Chinese).

[9] Y. Kim, R.G. Evans, W.M. Iversen, Remote sensing and control of anirrigation system using a distributed wireless sensor network, IEEETransactions on Instrumentation and Measurement, vol. 57, July 2008,pp. 1379-1387.

[10] G. Vellidis, M. Tucker, C. Perry, C. Bednarz, A real-time wirelesssmart sensor array for scheduling irrigation, Computers and Electronicsin Agriculture, vol. 61, April 2008, pp.44-50, doi:10.1016/j.compag.2007.05.009.

[11] Q. Zhang, X.L.Yang, , Y.M. Zhou, L.R. Wang, X.S. Guo, A WirelessSolution for Greenhouse Monitoring and Control System Based onZigBee Technology, Journal of Zhejiang University-Science A, vol. 8,Oct. 2007, pp. 1584-1587, doi: 10.1631/jzus.2007.A1584.

[12] Y.M. Zhou, X.L.Yang, X.S. Guo, M.G. Zhou, L.R. Wang, A Design ofGreenhouse Monitoring and Control System Based on ZigBee SensorNetwork, Proc. International Conference on Wireless Communications,Networking and Mobile Computing(WICOM 07), Sep. 2007, pp.2563-2567, doi: 10.1109/WICOM.2007.638.

[13] Jennic Ltd., Reference Manual: JN-AN-1001-Power-Estimation-1v3.pdf, Http:// www.jennic.com.

MCU JN5121

External

Flash

Memory

ROM RAM Trans

ceiver

GPIOSensors

Balun

RS232

GPIOActuators

LCDLeds &

Buttons

GPIO GPIO

External

Power/

Batteries

: for sensor node

: for actuator node

: for portable controller

(a)

Figure 2. Hardware architecture for the nodes (a), wireless sensor node (b), wireless actuator node (c), the portable controller (d).

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