Compared with the traditional way, agricultural Internet monitoring system for farmland information acquisition provides a new train of thought. Internet of things is through the radio frequency identification, information such as global positioning system, laser scanner, sensing equipment, according to the contract agreement, connect any item with the Internet, information exchange and communication, in order to realize intelligent identification, location, tracking and the sensor node layout in the target area of farmland etc., with a large number of real-time network node, gathers the precise temperature, humidity, light, gas concentration, such as environmental information, the information in the data gathering node collection, network analysis of the collected data, help producers have on the agricultural means of production, according to the to better realize the cultivated land resource reasonable utilization and precision agriculture modernization management, promoting the efficient management of agricultural production, improve agricultural production efficiency. An important application of Internet of things of agriculture monitoring system of wireless sensor network for farmland soil moisture information can satisfy the requirement of rapid, accurate and continuous measurements. Wireless sensor network (WSN) as a kind of brand-new information acquisition and processing technology, with its low power consumption, low cost, high reliability etc, has been gradually penetrating to the agricultural sector.
With the emergence of the Internet of things, for the implementation of farmland accurate operation process, the information acquisition of farmland environment requires more accurate and timely. At present, the main way of farmland information acquisition are: hand-held devices of artificial access method, based on the GPRS monitoring method and the way of monitoring based on WLAN and so on. Artificial rbis, using a handheld device for farmland soil information is one of the most original way, this way not only requires a lot of manpower, not real-time, and data access is limited, obviously can not meet the needs of the current farmland soil moisture monitoring. And soil moisture monitoring system is mainly composed of low power wireless sensor network node by white ZigBee network mode, to achieve continuous on-line monitoring soil moisture. Mainly includes two important parts: the environment in the area of wireless network part and realization of remote data transmission communication network. Wireless network choose a star network topology; Remote data transmission, is realized by using the Internet embedded Internet access technology was adopted to realize the wireless network and Internet network communication; For soil parameters such as temperature, humidity acquisition model to complete the environment parameter acquisition monitoring area. To meet the precision agriculture operation on information accuracy and real-time requirements.
1, wireless sensor network monitoring system as a whole framework
Wireless sensor network system includes two important parts, namely the realization of wireless network part and farmland environment in the region communication network part of remote data transmission.
Each Zigbee terminal connection sensors to complete data collection, data acquisition as Zigbee application layer application object in the form of port and the low-level communication protocol stack, data from the application layer to the physical layer. After the physical energy and idle channel scan testing idle channel, when get the idle channel, physical rf module data wireless transmission in the form of radio waves. The coordinator of the radio frequency module receives the packet, notify the upper receives the data, the physical data transmitted from the physical layer and layer to the upper, each layer is to remove the lower upward in baotou, tail to unpack the packet in this form. When data transmission to the coordinator application layer, data is sent via a serial port to network module, network module using the network protocol and the Internet network, wireless network and Internet network docking.
2, design of wireless sensor nodes
Sensor nodes of this research is the function of node and routing. On the one hand, realize data acquisition and processing; On the one hand, to implement data fusion, and routing of data collected by itself and received other nodes to send data synthetically, forward route to the gateway node. Sensor network node: the wireless transmission unit, the processor unit, the sensor unit and power supply module unit of four parts. Processor unit is the core of the wireless sensor nodes, together with other units to complete data acquisition, processing, and to send and receive; Wireless communication unit to complete to send and receive packets; Sensor module to complete the environmental data collection and conversion; Power supply module to provide power for the entire node system support.
3, system technical index
Low-power wireless sensor technology indicators: 1. The power of 10 row; 2. When receiving current < 18 ma, emission current is equal to or less than 40 ma; 3. The multichannel module standard provide four channel; 4. The networking function, only 128 of the wireless sensor network; 5. Interface baud rate for 1200/2400/4800/9600/19200 - bit/s, can be set up; 6 matching 450 mah battery. Wireless sensor network node design USES Zigbee protocol, USES the star topology. After the successful development of the wireless sensor network monitoring system, in addition to regional farmland soil moisture information monitoring, can also be widely used in grain reserve warehouse and fruits and vegetables, eggs, meat storage warehouse temperature and humidity control; Workshop environment temperature and humidity control; Lab environment temperature and humidity control, etc., with the enlargement of the Internet of things application scope, its market application is very wide.
