Pute Wu

A survey on wireless sensor network infrastructure for agriculture

The hybrid wireless sensor network is a promising application of wireless sensor networking techniques. The main difference between a hybrid WSN and a terrestrial wireless sensor network is the wireless underground sensor network, which communicates in the soil. In this paper, a hybrid wireless sensor network architecture is introduced. The framework to deploy and operate a hybrid WSN is developed. Experiments were conducted using a soil that was 50% sand, 35% silt, and 15% clay; it had a bulk density of 1.5g/cm^3 and a specific density of 2.6cm^-^3. The experiment was conducted for several soil moistures (5, 10, 15, 20 and 25%) and three signal frequencies (433, 868 and 915MHz). The results show that the radio signal path loss is smallest for low frequency signals and low moisture soils. Furthermore, the node deployment depth affected signal attenuation for the 433MHz signal. The best node deployment depth for effective transmission in a wireless underground sensor network was determined.

Overview of wireless underground sensor networks for agriculture

In recent years, many applications have been proposed for wireless sensor networks (WSN). One of these is agriculture, where WSN can play an important role in the handling and management of water resources for agricultural irrigation and so on. The WSN suffer from intensive human involvement and delay of information. This paper shows that the wireless underground sensor networks (WUSN), which communicates in the soil is different from the terrestrial WSN. WUSN devices are deployed completely below ground and do not require any wired connections. Each device contains all necessary sensors, memory, a processor, a radio, an antenna and a power source. Here, the WUSN architecture for agriculture information system is introduced. The framework to deploy and operate the WUSN is developed. Based on the framework, WUSN in different frequency, buried depth and volumetric water content of soil are tested and results are discussed. Key words : Wireless sensor networks (WSN), information collection, agriculture, wireless underground sensor networks (WUSN), buried depth, sensor node.

The research of an advanced wireless sensor networks for agriculture

The advanced wireless sensor networks constitute one of the promising application areas of the recently developed wireless sensor networking techniques. It contains two parts: the terrestrial wireless sensor networks (WSN) and the underground wireless sensor networks (WUSN). The main difference between the hybrid WSN and the conventional wireless sensor networks is the aspect of WUSN, which communicates in the soil. The terrestrial WSN suffer from intensive human involvement and delay of information. There lacks a coherent system that coordinates various technologies including the terrestrial and underground sensor networks to improve the system. In this paper, the hybrid wireless sensor network architecture for agriculture information system is introduced. The framework to deploy and operate the hybrid WSN is developed. Based on the framework, research tests and results are discussed.

ELECTROMAGNETIC WAVE PROPAGATION IN SOIL FOR WIRELESS UNDERGROUND SENSOR NETWORKS

Wireless underground sensor networks (WUSN) consist of wireless devices that operate below the ground surface. These devices are buried completely under dense soil, thus electromagnetic wave transmits only through soil medium. However, the high attenuation that caused by soil is the main challenge for the electromagnetic wave transmission for WUSN. In this study, architecture of wireless underground sensor network communication was established. The experimental measurements were conducted using WUSN sensor nodes at three difierent carrier frequencies, respectively. Received signal strength and packet error rate were examined for communication links between the sensor nodes. The test results showed that carrier frequency was one of the main factors that afiected electromagnetic wave propagation in the soil medium. It was concluded that the burial depth of the sensor nodes, horizontal inter-node distance, and soil volumetric water content have signiflcant impacts on the signal strength and packet error rate during the electromagnetic wave propagation within a WUSN.

Design and test of nodes for field information acquisition based on WUSN

The wireless sensor network technology was researched. Some wireless underground sensor network nodes and a sink node based on embedded technology and RF technology were designed innovatively. WUSN node consists of sensor, the processor, wireless communication module and power module, including processor using MSP430 microcontroller, RF modules adopting nRF905 communication module which having 433/868/915 MHz 3 ISM channel, the sink node is made up RF transceiver module, the core control circuit, information processing, data storage, LCD module and power supply. The nodes which acquired soil parameters information were regularly distributed in the monitoring area. The sink node collected the information of nodes that were sent in way of a single jumping or multiple hops and implemented fusion, analysis, processing, storage and display of information. For 50% sands, 35%silt, and 15% clay, a bulk density of 1.5 g/cm3 and a specific density of 2.6 / cm3, test for different soil moisture (5%, 10%, 15%, 20% and 25%) in three different frequencies, result shows that radio signal path loss is the minimum in the low frequency and low moisture. Moreover, the changes of node deployed depth (0.2 m, 0.4 m, 0.6 m,0.8 m, 1m, 1.2 m, 1.4 m, 1.6m, 1.8 m and 2m) affected signal attenuation under 433MHz, it is concluded that the best WUSN node buried depth for effective transmission.

Remote monitoring system for agricultural information based on wireless sensor network

Abstract To achieve a widely dispersed, diverse network, reflecting natural complexity for agricultural information gathering, an agricultural information remote monitoring system has been developed based on a combination of the ZigBee and the GPRS networks. Data collection of agricultural information was completed using a CC2430 radio frequency chip. Our base station was designed and developed based on ARM9 processors and an embedded Linux operating system, which received, stored, and displayed the agricultural information, and communicated with the remote monitoring center by GPRS. Test results have a data sampling interval set for 40 min. The system ran reliably while collecting data accurately. It met the system design requirement and all practical demands. Finally, the system provided good prospects for use in agricultural information remote monitoring. This is a good example of using the Internet for farming.