Design And Study For Automatic Control System Of The Wireless Water-saving Irrigation

The freshwater resource is lacking in China,hence, developing the high efficient saving-water irrigated argriculture is the initial requirement to the sustainable agricultural development. At present,most water-saving irrigation control system have singal function,and which mainly employ wired control mode. So the control system is limited by the landforms,furthermore constructing wires costs too much. Thus researching a wireless system with scinentific controlling means has becoming the central issue to scientific applicate of water-saving irrigation.The paper studies and analysis the control principles of the wireless water-saving irrigation control system,and foucus on the design of hardware and software based on sufficient researches on national and foreign status of water-saving irrigation.In the respect of hardware design, according to the precision, time and the cost of the detector, we select the appropriate chips and divide the whole hardware system into several modules to design respectively following the theory of module design. When each module is adjusted successfully, we combine them into a complete entity to ensure the high quality of hardware and makes it easy to test and maintain. In the respect of software, according to the predicted function of this detector and the design of the hardware circuit, the software is specified as follows: initialization for MCU and system chips, sampling analog signals, signal process, real time display and serial port communication on MCU, and program interface design, serial port communication etc. The system needn't work in the wet weather,so efficiency is raised and energy is saved as well as labour because solar cells are used to offer power.The control system works in the way of command response,the master station gives the order to collect data, the sub-station processes the address information from the master and carries the order out if the address fits the local address . Environmental parameters of growing planta (soil moisture,air humidity and temperature) are send to PC in substation after changing them to digital signals by A/D transformation module. The PC encodes the signals and adds start bit as well as check sodes into the coded signals to form transmittal data frames. PTR8000 packes Frame signals under specified agreement,addes head word and CRC into signals,then sents them to master station.After eliminating noises ,carrier singals received by receiving aerial are demodulated by PTR8000 .Then the PC decodes them and put them into database. At the same time ,the the irrigation forecast and control module are designed to determine water requirement of plants to control opening or closing the electromagnetically operated valve by the drive circuit.