2010 International Conference on Environmental Engineering and Applications (ICEEA 2010)

A Prototype of PC Based Remote Control of Irrigation

Mahir DURSUN Department of Electrical Education

Technical Education Faculty Gazi University Ankara, Turkey

mdursun@gazi.edu.tr

Abstract-In recent years, more efficient and positive use of current water resources together with global warming becomes

important. New technologies and ideas have been developed for many years to optimal use of water resources especially in agricultural field. Growers irrigate their own areas uniformly.

However demand of water, fertilizer and agricultural chemicals are different for each trees or crops depending on plant ages and chemical content of soil. Determination of water demand for crops and trees is important to protect fresh water resources. In this study, a prototype of solar powered, low cost,

remote controlled real time monitoring irrigation system was designed to control drip irrigation. Software (VaICon, developed by authors with C# language in Visual Studio.Net 2008 editor) was developed to control irrigation valve and monitor water content of soil. Control method of irrigation (automatic or manual) can be selected by users. Only water content of soil was monitored. Nevertheless by using sensors

which measure other features of water or air, it is also possible to extend the designed system. Remote controlled site-specific irrigation scheme prevents moisture stress of trees and salification besides providing the efficient use of fresh water

resources. Also, this irrigation method removes labour that is needed for flooding irrigation

Keywords- Soil moisture sensor, wireless, irrigation, real time monitoring, ValCon

1. INTRODUCTION

Drought caused by global warming is the most important problem of the world. Effective management of scarce water resources is of paramount importance. Agricultural irrigation has large proportion of current estimates of fresh water consumption. Therefore, efficient water management plays an important role in irrigated agricultural cropping systems [1]. This research was designed to prevent unnecessary watering with controlling drip irrigation according to features of crops, trees, orchards. Based on yield variability in orchards, it is evident that many trees receive too much or too little water and fertilizer under uniform management. The requirement of individual tree in an orchard may vary due to such things as soil condition, tree age, elevation changes, or localized pest infestations. When applied uniformly, water and fertilizer may leach in light textured soils and pool in heavy soils [2]. A site-specific wireless sensor-based irrigation control system is a potential solution to optimize yields and maximize water use efficiency for fields with variation in water availability due to different soil

978-1-4244-8621-2110/$26.00 © 2010 IEEE 255

Semih OZDEN Department of Electrical Education

Technical Education Faculty Gazi University Ankara, Turkey

semihozden@gmail.com

characteristics or crop water needs and site-specifically controlling irrigation valves [3].

In many years, researchers have been studying sensor­based irrigation systems [4-6]. With developed wireless technologies, researches focused on automatic irrigation with sensors in agricultural systems [7,8]. The advantages of using wireless sensor is to reduce wiring and piping costs, and easier to install and maintenance especially large areas [9-12]. On the other hand, excessive irrigation leads to leaching of fertilizer (N, P and other chemicals), inducing groundwater pollution and soil degradation [13]. Temporal monitoring of soil moisture at different growth stages of crop could prevent water stress and improve the crop yield [14]. Also different type of sensors and technologies were applied to control of irrigation systems [10, 15-20]. Nevertheless adaptation of producers has been limited due to cost, installation time, maintenance, and complexity of the decisions involved [3, 21].

The objectives of this research were to develop and produce applicable remote controlled control system of irrigation with real time monitor. Designed system was provided site-specific management of irrigation systems with solar powered wireless acquisition stations. Portable 3 units and software named ValCon were developed. These units consist of a PC, Measure Unit (MU) and Control Unit (CU). All of these units involve UDEA brand RF module, omni­directional antenna, 7 V -1.8 W solar panel and low power Microchip PIC18F452 micro controller chip. Additionally the MU has soil moisture sensor, the CU has 12 V, 10 W normally-closed solenoid valve and battery. ValCon allows selection of control type (automatic or manual). Data received by MU with RS-232 serial port was monitored and valves were controlled according to control strategy in ValCon. In the current implementation, only one soil moisture sensor and water valve was used, nevertheless in future work, with adding new sensors and valves, the system will be improved. The planned work for future application is to develop a wireless valve network capable of controlling application of water, fertilizer, and agricultural chemicals through each valve.

II. SYSTEM DESIGN

Designed systems are portable with solar power and it allows that sensors and valves to be replaced the points where soil moisture is measured. In addition, the system

2010 International Conference on Environmental Engineering and Applications (JCEEA 2010)

alJows when and where to irrigate, and how much water will be applied.

A. Units

PC Unit (PU), Measure Unit (MU) and Control Unit (CU) were designed to realize control of drip irrigation. AIJ of these units involve RF module, antenna, 7 V, 1.8 W solar panel and Microchip PIC18F452 (MCU). This MCU was selected due to low-cost, processor speed, low power requirements, rapid software development, and ease of system integration with custom circuits so that a cheap irrigation system could be achieved. Electronic devices, sensors, and solenoid valves were selected to meet the low power and low cost required for the system. Software of PIC was written with C language. UFM-Mll produced and marketed by Udea Technology Inc. was selected as RF modules. This low power wireless module works 434 MHz with UGP A-434 coded omni-directional antenna. Radio transmission range of module is 400-500 meters in environmental conditions. UFM-Mll uses Frequency-Shift Keying (FSK) modulation and maximum output of power is 10 dBm. Power consumption is 10 mW at 434 MHz and current consumption is 17 rnA receiver mode, 30 rnA transmitter mode. RF wireless modules were adjusted to communicate with 9.6 Kbps baud rate with MCU.

10HS coded pre-calibrated Soil Moisture Sensor of Decagon has been used to measure water content of soil in MU. Power consumption of lOHS is 12-15 rnA and Output voltage is 300-1250 m V (independent of excitation voltage, 3-15 V DC). Measured analog data was sensed with ADC on PIC chip and transmitted to pu. The lOHS measures the dielectric constant of the soil in order to find its volumetric water content (VWC) using a capacitance technique. The MU used is shown in Fig. 1.

Figure 1. Example of a ONE-COLUMN figure caption

The Valve unit was used to control of valve with a digital output of PIC. PVD Brand, Yz", normalJy-c1osed solenoid valve was driven by transistors (MJE3055). It has a 12 V, 10 W coil. The solenoid valve is shown in Fig 2. AdditionalJy, a battery was used to obtain desired power to drive valve.

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Figure 2. Valve and UGPA-434 RF antenna

The PC unit was used to colJect data and control valves. Solar panel, the PC Unit and connection system of PC and RF antenna are shown in Fig 3.

Figure 3. PC unit, solar panel, antenna and connection hardware

III. SOFTWARE (VALCON) ValCon developed by authors with C# language in Visual

Studio.Net 2008 were used to control valves and colJect data. Control method of irrigation (automatic or manual) could be selected by users. User interface of Val Con is shown in Fig 4. Manual and automatic control must be select by users. Data of sensors is shown in text box related to sensor number in both of two selections. Val Con alJows saving sensor data, which is optional, in a file with extension of x.dat. Communication with RS-232 features can be selected to establish connection with MU and CU.

2010 International Conference on Environmental Engineering and Applications (ICEEA 2010)

Valeon

D Sensor A I Valve 1 J:J ]CLOSED I

D Sensor

I I A I Valve 2 J:J lCLOSED

I

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I I I , ContI<. Method

o Automatic Control

o Manuel Control

o Save Sensor Data?

� Figure 4. User interface of Val Con

In manual control, user could select valves which will be opened or closed. After selecting valves status, "Update Valves Status" button must click. Data of desired valve position will be sent and status will be updated if validation checkbox is "OK". Manual Control user interface of Val Con is shown in Fig. 5. In automatic strategy, valves are controlled by software with determined threshold value. Moreover existing valve positions could be checked with "Check Valves Status" button. Close button in user interface used to close serial port communication and to stop software. Automatic Control user interface is shown in Fig. 6.

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Valve 7

lO ON 0 OFF

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vl vi I Check Valves 1 r Update Valves 1

Status Status

o Save Sensor Data? Open Serial POI't I Close Se,,, Po,t I

� c:\V alCon\201 00722_1 S.34.dai

Figure 5. Manual Control user interface of Val Con

257

Valeon

Threshold Value [EJ Sensor 1 A Valve] J:J D Sensor A Valve 2 � D Sensor A Valve 3 J:J

OPENED 1

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30

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Control Method

o Automatic Conhol

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c:IValConl201 00722_1 S.34.dat

Figure 6. Automatic Control interface of Val Con

IV. CONCLUSION

In this paper, a wireless data acquisition network was designed and implemented to control irrigation. Low cost, reliability and portability were three main goals of this design. All the system units were designed and implemented by authors. In the system, Basic unit (PU), sensor and valve cost under 100$, 200$ and 210$, respectively. ValCon was developed by authors to monitor and save soil moisture data with date and time. Thus growers would know the irrigated places and accordingly would make decision for irrigation period to reach desired irrigation level. The realized system provides effective management of scarce water resources and inhibits tree dead cause of too much irrigation. Also this sensor-based site-specific irrigation prevents moisture stress of trees and salification. Although the system was designed for only irrigation, it could be converted to automatic fertilizer with adding agricultural chemicals.

ACKNOWLEDGMENT

This project fund Turkish Ministry of Industry and Trade named project 00228.STZ.2008-1 SANTEZ and Zile Mercantile Exchange.

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2010 International Conference on Environmental Engineering and Applications (ICEEA 2010)

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