| The grain problem has been always the most important considerationrelated to the national economy and the people's livelihood in our country, butthe existing grain circumstance monitoring system is based on a wired way. Thewired way has its inherent defects, such as connecting up complicatedly, easilyto be struck by lightning, expensive installed and safeguarded cost, easily to bedestructed etc.In recent years, some monitoring systems based on GPRS network andwireless data transmission appear. But because of their expensive cost, theconsumption is great or the frequency band is limited, etc. the systems aredifficult to spread. Until the presence of wireless sensor network and theIEEE802.15.4 intemational standard for the wireless sensor network specially,these problem are solved.The most basic characteristic of the wireless sensor network is lowconsumption, low cost, flexible network; its application is very wide, suitablefor the grain circumstance monitoring system too. This text has introduced the background of the subject and relevantconcepts, the meaning of the subject and problem solved at first, then the choice,nodal design, design of the procotol inn and design of the management softwareof the systematic scheme are introduced. Finally, the field test situation after thesystem is installed is introduced briefly.The final goal of the subject is to realize the wireless grain circumstancemonitoring system of a low consumption, low cost and high dependability.The characteristics of GPRS network and several kinds of short distancecommunication schemes are analyzed and compared in "choice of systematicscheme" of this text. At last, the conceptual design is confirmed on the basis ofthe wireless sensor network and IEEE802.15.4 standard finally.Considering low consumption, low cost and performance of chip fully atthe "nodal design", the main control chip of node and radio frequency receiveand transmission chip are chosen. And each nodal hardware platform ofmonitoring system of the wireless grain circumstance is designed on this basis.In "design of the procotol inn", according to the real characteristic of thegrain depot, the agreement inn of IEEE802.15.4 standard has been analyzed andoptimized on the basis of it so as to reduce consumption and improvedependability. The part of "design of management software" introduces theselection of software platform, collection function and creation of database.The circumstance monitoring system of wireless grain has adopted theinternational and current agreement standard, use the latest chip technology, detailed and careful, scientific and rational. In transmitting the agreement, adoptthe short frame way, on the work pattern, adopt the low consumption modeand work pattern moving ahead simultaneously (at the time of namely the workmove ahead simultaneously) at any time, on the basis of stressing lowconsumption , meet the demand of low cost and high dependability. Thesoftware platform adopts access that the country stipulates and matches VisualBasic 6.0 bestly, designing technique adopts the latest database operatingtechnology ADO continuous data source.The characteristic of the wireless grain circumstance monitoring system oflow consumption is: Adopting the latest technology and standard, the researchapproach is advanced, design is rational, dependability is high, low cost, lowconsumption, 2 ordinary alkaline batteries can make the system run for 3 to 5years continually, the test result accorded with the demand of the national graindepartment, can meet the demand that various kinds of grain circumstancesmonitor. It has good popularization and application prospect.The design and realization for the wireless grain circumstance monitoringsystem of low power consumption have solved the problems which were notsolved best in the past elementarily. It improves grain monitoring andmanagement level of the grain depot. This is significant to the modernizedmanagement of the national stored grain. |
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