Wireless information system for frost detection in orchards

Transcription

1 Original research paper; UDC: 634.1/.7:[621.39:004.7 ID: Acta Agriculturae Serbica, Vol. XVIII, 36(2013) Wireless information system for frost detection in orchards Dušan B. Marković, Ivan P. Glišić Faculty of Agriculture, University of Kragujevac, Cara Dušana 34, Čačak, Serbia Uroš M. Pešović, Siniša S. Ranđić Faculty of Technical Sciences, University of Kragujevac, Svetog Save 65, Čačak, Serbia Abstract: Electronic devices are widely used in many fields and agriculture is also one of the areas with great intensity of applications in the last years. Electronic sensor devices are particularly interesting because they are enable measure of parameters which have a major impact on agriculture production. The use of electronic devices additionally came to the fore with the development of wireless communication that allows gathering timely information about the status of important parameters for vegetables and fruit crops. Occurrences of frost represent high risk for orchard especially in the flowering stage because low temperature can destroy flowers and therefore the overall yield of fruit. In this paper system for frost detection in orchards was presented and database with parameter values significant for user of the system. The system was based on wireless sensor devices which collected data sent by GPRS network to WEB server where they are stored for further analysis. Also WEB application was created to enable data distribution to users. Key words: frost protection, orchard, intelligent sensors, wireless sensor network, WEB server. Received: / Accepted:

2 180 Acta Agriculturae Serbica, Vol. XVIII, 36 (2013) Introduction In the conditions of the continental climate, characteristic for Serbia, occurrences of frost are very often and may cause significant losses of fruit crops due to low temperature damage. Fruit growers are faced with this problem since the planting of orchards. From the beginning of vegetation to the stage of fruit setting there are risk of freezing unopened flowers, open flowers and newly fruits settings. Unopened flowers are freezing on temperature of -5 to -8 C, open flowers to -2 C, where fruit setting are damaged by frosting in temperatures from -1 to +2 C. The last phase from these three phases is characterized with the greatest sensitivity to the value of temperature because the time of the year responsible for fruit setting occurs when higher temperature is reached. These suitable temperature conditions are necessary for developing of fruit setting but problems could cause occurrence of frost in the late night hours when temperature could drop down and damage flowers. Protective measure must be taken to save fruit in this situation, and some of them are smoke cloud, heating air, temperature inversion, protection by water sprinkle or irrigation, artificial fog. Dense smoke curtain could be used to prevent heat transfer from the ground and increase temperature in the orchard for 0,5 C to 1,5 C. But this method is not offering safe protection in the case of strong frost. Machine with heater on the basis of oil or other fuels are using to warm the air and its spreading. Cooling of air in the area of orchard could be preventing continually adding worm air by moving machine across orchard. Temperature inversion could be established by giant ventilator which could push warm air in orchard area and increase temperature for 2 or 3 C which is quite enough for protection. Orchard frost protection could be performed by irrigation and represent spraying flowers or fruit settings with fine water drops in the form of mist when the temperature is decrease below 0 C and all the period during this critical temperature. The method is based on exothermic process when turning water into solid physical state is accompanied by the release of heat. Due to the low temperature, water on wetting fruit quickly freezes, forming a protective crust on the surface, while the inner tissue is not affected by cold due to release heat. With higher amounts of water, within certain limits, frost protection could be accomplished at lower temperature that could be hardly feasible with other methods. Spraying with water must begin in the right time when temperature is drop down to 0 C and must continue all the time during period of low temperature without making pause. The interruption of water spraying in orchard is unacceptable if lasts longer than 3 to 4 minutes (Perry 1998, Sugar et al. 2003, Zaštita voćaka od mraza). 180

3 Acta Agriculturae Serbica, Vol. XVIII, 36 (2013) Methods for frost protection could be applied in the best manner if the fruit growers have information when to intervene and prevent frost killing flower in orchard. This information could be obtained by small wireless devices deployed in orchards. Wireless devices is equipped by temperature and other sensors, they communicate with main device and transmit gathering data to remote station. Wireless sensor network (WSN) form in this way could monitor microclimate conditions on covered orchard area; send current data on which value some action could be performed, such as notification fruit growers about approaching low temperature in the field. One of the automated WSN system for frost protection were presented in Alboon et al where sensor data were collected to the controller who could use solid fuel burner to get an artificial smoke cloud to keep temperature in orchard. WSN technology were widely used in precision agriculture where one of the possible purpose is also frost protection of vegetable or fruit crops (Valente et al. 2011, Ghobakhlou et al. 2009, Panchard et al. 2008, Shanmuganathan et al. 2008). Besides frost prediction and automated reaction or send notification to system users, WSN system could be used in making decision about potential places for planting. The aim of this work is to present Wireless sensor devices that could send data by gateway node to remote server. This system could be implementing very easy, gather sensor data and sending them using GPRS services of mobile operators to servers. Then data could be analyzed and notification could be send to users when condition reaches critical value. Results and Discussion Wireless sensor devices were placed on two locations in the same orchard which is characterized by bigger slope, so there was a difference in altitude on the field. Also special circumstances were represented by existence of small water stream near lower point. Deploying wireless devices and monitoring microclimate conditions specific results were obtain that show temperature difference between these to measure points. Although there is no need for frost protection in the wide range small water stream is responsible for lower temperature in its near zone and that part of orchard is required some action from farmers or fruit would be lost totally. Implementation of the wireless system in this case contributes to determine zone with special microclimate conditions. This situation on the field leads to addition request for fruit growers that they did not take into account. Experience by deploying wireless devices, gathering and processing data in this concrete case could be mapped on much larger area and then could be used to asses were the particular location the most appropriate for orchard. System for frost detection is composed from number of mobile sensing stations, which are capable to measure temperature and relative air humidity 181

4 182 Acta Agriculturae Serbica, Vol. XVIII, 36 (2013) (Figures 1 and 2). Stations are equipped with SHT15 digital air temperature and relative air humidity sensor, which offers small footprint and small power consumption, for high precision and low sensor cost. Each sensor is individually calibrated in a precision humidity chamber, which provides long term stability. Temperature is measured by silicon bandgap sensor in range from -40 C to 125 C with air temperature accuracy ±0.3 C. Relative air humidity is measured by capacitive sensing sensor in range from 0 to 100% with relative air humidity of accuracy ±2%. Sensors can be equipped with protective membrane, which protects sensor from dirt and droplets from entering sensor housing. Sensors are also equipped with small heater which can be turned on in order to dry sensor or test its functionality. Sensors are equipped with one time programmable memory which stores calibration data and digital I2C digital communication interface which is used to read air temperature and relative air humidity, as well as issuing commands by microcontroller. Main component of mobile sensing station represents digital microcontroller, which is responsible for overall control of mobile station functionalities. Microcontroller used in this station is based on Telit GM862-GPS module, which controls operation of mobile sensing station using commands written in Easy Python script. Besides microcontroller functionalities integrates GSM/GPRS modem, as well as GPS receiver. GSM/GPRS quad-band modem enables remote communication using mobile network which is almost available worldwide. Besides voice and SMS messages, modem can communicate using Internet services thought GPRS service, such as HTTP, FTP and . This functionality enables simple interaction with users worldwide, using personal computers of smart telephones. GPS receiver enables detection of mobile station location, with 2.5 m precision, using 20-channel high sensitivity SiRFstarIII single-chip GPS receiver. Microcontroller has low power consumption so it is designed for battery powered operation with Lithium Ion or Lithium Polymer batteries, in voltage range from 3.2 to 4.2V. In order to make mobile stations completely independent they are equipped with photovoltaic solar cells which are used for recharging batteries. Use of solar energy power supply, offers cheap and reliable energy source, which doesn t require maintenance as frequent battery replacement or any addition cost as electrical power used from distribution grid. 182

5 Acta Agriculturae Serbica, Vol. XVIII, 36 (2013) Figure 1. Wireless sensor stations placed in different zones Mobile sensing station software, written in Phyton, first initializes GPS service and tries to determine GPS coordinates of mobile station. As GPS fix is acquired, station connects to GPRS service, and registers at web server reporting it identification number, as well as acquired GPS coordinates. After successful registration web server sends server time to mobile station which presents its clock, in order to perform regular reports at certain instances in time (currently set to 15 minute report interval). Microcontroller reads measures air temperature and relative air humidity values from SHT15 sensors, forms HTTP GET request which is sent to web server. Besides these two values, sensor reports battery voltage level as well as cycle ratio which is used for mobile station diagnostics. After successful transmission, mobile station goes to low power operating mode in order to preserve battery energy, from which is woken by clock, when another report interval begins. On the server side web application was developed using Java technology. Software application has three main parts: HTTP GET request parsing, application logic and presentation data. The first segment of software solution has a role to parse and accept data sent from mobile stations. It was realized with servlet which has ability to communicate by HTTP protocol. Accepted data were store to database and could be used for further analysis. Application logic is used for data calculation and creating array of data for web presentation to the users. For making decisions users of the system need some calculated values such as average or minimal and maximal value for defined time period. User could interact with Web applications through appropriate user interface and set task to the system according 183

6 184 Acta Agriculturae Serbica, Vol. XVIII, 36 (2013) to their needs. Results of the users requests were presented on the web page while in the background there are conducted data processing on stored data. Except searching and analyzing data stored in the past web application has the ability to presenting current data in the real time. The last arrived data from the field station is shown on the main page of the web application. So that user could monitor field conditions from any computer which has access to Internet. Server side system could be upgraded with web application customized for smart phones or with module for sending SMS to users based on the set tasks. Figure 2. Wireless sensor station in the orchard Conclusion The development of new electronic devices, such as smart sensors, provides the conditions for the expansion of their use. One of the new areas of application of smart sensors is agriculture. This paper gives an example of using smart sensors and their networks to detect the appearance of frost in orchards. The developed system, and conducted measurements, shown that the occurrence of frost can be detected successfully. The system enables detection of occurrence of frost in orchards and memorizing the received data on the web server. Further research is planned to implement a system for informing users about the occurrence of frost. Also planned are researches regarding activation of adequate protection in case of occurrence frost. 184

7 Acta Agriculturae Serbica, Vol. XVIII, 36 (2013) Acknowledgement Work presented in this paper was funded by grant TR32043 for the period , by the Ministry of education, Science and Technology Development of the Republic of Serbia. References Alboon A. S., Alqudah T. A., Al-Zoubi R. H., Athamneh A. A Fully automated smart wireless frost prediction and protection system using a fuzzy logic controller. Int. J. of Artificial Intelligence and Soft Computing, 3: Časopis Voćarski Glasnik 2008, Zaštita voćaka od mraza, Časopis za savremeno voćarstvo, Voćarski Glasnik br. 1. Ghobakhlou A., Shanmuganthan S., Sallis P Wireless Sensor Networks for Climate DataManagement Systems. 18 th World IMACS / MODSIM Congress, Cairns, Australia, Panchard J., Rao S., Sheshshayee S. M., Papadimitratos P., Kumar S., Hubaux J-P Wireless Sensor Networking For Rain-fed Farming Decision Support, Proceedings of the second ACM SIGCOMM workshop on Networked systems for developing regions, Seattle, WA, USA. Perry B. K Basics of Frost and Freeze Protection for Horticultural Crops. Hort Technology, January-March (1). Shanmuganathan S., Ghobakhlou A., Sallis P Sensors for modeling the effects of climate change on grapevine growth and wine quality. Proceeding of the 12th WSEAS International Conference on CIRCUITS Heraklion, Crete Island, Greece, Sugar D., Gold R., Lombard P. and Gardea A In: Oregon Viticulture, Strategies for frost protection, Editor, E.W. Hellman, Oregon State University, pages Valente J., Sanz D., Barrientos A., del Cerro J., Ribeiro A., Rossi C An Air- Ground Wireless Sensor Network for Crop Monitoring. Sensors, 11:

8 186 Acta Agriculturae Serbica, Vol. XVIII, 36 (2013) Bežični informacioni sistem detekcije mrazeva u voćnjacima - originalni naučni rad - Dušan B. Marković, Ivan P. Glišić Agronomski fakultet, Univerzitet u Kragujevcu, Cara Dušana 34, Čačak, Srbija Uroš M. Pešović, Siniša S. Ranđić Fakultet tehničkih nauka, Univerzitet u Kragujevcu, Svetog Save 65, Čačak, Srbija Rezime Poljoprivreda je postala jedna od oblasti u kojoj primena elektronskih uređaja dobija na intenzitetu. Posebno značajan aspekt primene obuhvata oblast merenja različitih parametara koji utiču na poljoprivrednu proizvodnju. Primena elektronskih uređaja u poljoprivredi dodatno je došla do izražaja sa razvojem bežičnih komunikacija, jer se na taj način omogućava pravovremena informacija o stanju parametara važnih, npr. za voćnjake, povrtnjake i dr. Pojava mraza predstavlja veliku opasnost za voćnjake posebno u fazi cvetanja, jer može doći do uništenja celokupnog roda. U ovom radu je prikazan sistem za detektovanje mraza u voćnjacima i formiranje baze podataka o intenzitetu mraza i vremenu kada je do njega došlo. Sistem je realizovan na bazi bežičnih senzora, koji prikupljene podatke putem GPRS mreže prosleđuju WEB serveru na kome se podaci upisuju u odgovarajuću bazu podataka. Realizovana je i odgovarajuća WEB aplikacija koja omogućava distribuciju zapamćenih podataka do krajnjeg korisnika. Ključne reči: Mraz, voćnjak, inteligentni senzori, bežične senzorske mreže, WEB server 186