Microclimate real-time monitoring based on ZigBee sensor network Natthapol Watthanawisuth and Adisorn Tuantranont Nanoelectronics and MEMS Lab National Electronic and Computer Technology Center Pathumthani, Thailand Natthapol.watthanawisuth@nectec.or.th Adisorn.tuantranont@nectec.or.th* Teerakiat Kerdcharoen Department of Physics and Center of Intelligent Materials and Systems Faculty of Science, Mahidol University Bangkok, Thailand teerakiat@yahoo.com Abstract—Monitoring microenvironment at the farm level has recently become one of the hottest topics in precision agriculture. Zigbee technology is then the most prospective candidate for wirelessly networking those field sensors due to its low cost and power consumption and flexible architecture. The microclimate monitoring system in this research is a suit of equipments based on Zigbee networking to measure the air temperature and humidity in a vast area. Every sensor node works on a cluster tree topology which extends the point-to- point distance up to 1 mile (line of sight), allowing this system to cover large farm using less sensor nodes. A sensor node consists of a micro-controller unit connected with air temperature and humidity sensor chips which are packed in a cylindrical louvered housing to prevent fault air temperature and humidity data from solar radiation. Every sensor node uses energy from a solar cell charged by a charger circuit to a battery package that stores power for use during night time. An energy management scheme was implemented to optimize power use for sending and receiving data. The data from every node were sent to the receiver every 8-30 minutes, depending on backup energy status at each node. The humidity and temperature data are stored on a data-logging PC and only current data are displayed on website I. INTRODUCTION Precision agriculture creates new opportunities for managing farm with higher control of input and output. It allows farmers to optimize resources, maximize yields and minimize wastes released to the environment. To practice precision agriculture, farmers have to know parameters relevant to their crop growth. Climate is one of the most important environmental parameters that determine the yields of ranch. Hence, microclimate real-time monitoring system is usually used as a tool for obtaining such information. Wireless sensor network technology has been known for scalability, carefree operation and easy installation In this research, we have developed a wireless sensor network based on IEEE 802.15.4, or the so-called ZigBee, to acquire real-time climate data in a cultivate area. Several groups have previously reported on monitoring of micro- climate for agriculture. Davis and Adam [1] have developed wireless microclimate sensor for tracking of the critical environment. Xia Ming and co-workers [2] described a long- range wireless sensor system for long-term microclimate monitoring in wild land cultural heritage sites. Jzau-Sheng Lin [3] demonstrated promising concepts and techniques of monitoring systems based on wireless sensor network, which integrates a system on a Chip (SoC) platform and ZigBee technology for precision agriculture. All wireless sensor hardwares operate upon a short-range communication between 10 to 300 meters. Such platform must employ a lot of nodes in order to cover area large area of farmland. In this research, we instead explored a Zigbee network using long-range point-to- point communication. This architecture would allow a small number of nodes to be installed in a vast area. Farmers can access these real-time microclimate data on a web site. II. WIRELESS SENSOR NETWORK AND ZIGBEE A. Wireless Sensor Networks (WSNs) Wireless sensor networks (WSNs) have become a popular topic in the field of wireless applications for the reason that WSNs can offer some advantage over other wireless systems, especially scalability. This work was focused on the capability of wireless sensor networks as an efficient tool to monitor farm-level climate in a large area. As a matter of fact, there are three popular standards in the wireless sensor industry, namely, Wi-Fi, Bluetooth and Zigbee. In the last couple of years, Zigbee technology has increasingly become a dominating player in the field of precision agriculture because of its advantages in topology, flexible architecture and especially lower price. Recently, Zigbee technology has been significantly improved on its ability to transmit data over the long range (i.e., up to 1 mile), thus making it viable for large farm applications. 978-1-4244-5335-1/09/$26.00 ©2009 IEEE 1814 IEEE SENSORS 2009 Conference