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1、山东理工大学 毕业设计（外文翻译材料）学 院：专 业：学生姓名：指导教师：电气与电子工程学院 电子信息工程 张汝岐 谭培红 2011年 6 月 The design Based on AT89S51 miniature soil humidity detector designAbstract: facilitate master soil moisture conditions, design the miniature soil humidity detector. Its hardware system includes signal amplifier circuit, A/D cir
2、cuit, SCM, micro LCD display and alarm circuit, etc.; Software system includes A/D conversion driver, LCD driver two modules. Proteus software platform based on the design of the system is simulated, and the results show that the system hardware and software design correct and reliable operation.Key
3、words: soil humidity; Detector; SCM; A/D conversion; simulationTP202 classification number: ChineseLiterature identification code: ASection 1 IntroductionAgricultural production in the economic development of our country has important position, for farmers Industry production to provide timely and r
4、eliablly technical service has become the heavily meteorological department To response one. Along with the national governments at all levels of agricultural production increasingly heavierDepende on the service, my unit also serve for agriculture, promote for increasing farmers incomeMany studies,
5、 the various problems in agricultural production also widely adjustableInquiry. Research found that gardening cultivation, greenhouse flowers, awning vegetables oneSome valuable varieties of soil moisture, soil has a high requirement, humidityAt the time, not only seriously affecting its normal grow
6、th, and even cause planting product death Wu, causing serious damage. Farmers Therefore, engaged in this kind of agricultural production.Farmers very need a low cost, small volume and detection reliable soil .Soil humidity detector for water supply, provides the basis. In order to solve the above as
7、ked .Our problem, I unit combined with actual conditions of agricultural production, and the related units designedHome of high precision, to design the low cost of miniature soil moisture detection instrument.Along with the social life progress, peoples quality of life is getting much more better,
8、flowers has become a fashion. Flowers can not only enrich peoples cultural life and is good for mental and bodily health ，but also can improve and purify air, improve health. Water is necessary for flowers growth ,it influences the growth of flowers greatly. Too much water or too little, will affect
9、 the normal growth and the kind of flower is verious, Different flowers need different amount of water. The needful water, mostly from the soil, in order to control flowers moisture in the soil properly, using PRO - F soil humidity sensor design an automatic watering the flowers system, it may, auto
10、matically set for flowers watering according to the humidity limit, in order to meet the need of imperative water.Section 2 composition of the system The whole system consists of SCM, circuit of DAQ, keyboard input and digital display circuit, output controlling circuit etc. circuit of CAQ is made o
11、f 4 SRH and adc , SRH makes flowers soil humidity convert into analog voltage output, adc makes the output of analog voltage convert into digital quantity and send to microcontroller. AT89S52 is adopted, the collectted value of soil humidity is compared with a preset limit soil moisture, and it make
12、s corresponding judgement according to the compared results, to control the output controlling circuits action. Key-in is used to set the value of soil humiditys limit, LED is used to display the current soil humiditys value.Miniature soil detector signal processing system including soil humidity se
13、nsorDevice, A/D acquisition circuit, SCM and micro LCD. Its work After cheng is: soil soil wet degrees preach sensor, will wet degrees letter sent to A/D adopt set electricityRoad, the A/D conversion, income data digital signal into SCM Processing, finally will processing results sent to micro LCD d
14、isplay.Section 3 the hardware design of system 3.1 the circuits working principle The hard thing the original reason system graph as figure 2 shows. This article selects KSC -6V integrated relative humidity sensor, wait for after inserting the soil about 5s make sensorImplement fully contact with th
15、e soil, signal by integrated amp LM324 Vin the same phaseInput terminal. The sensors relative humidity 0% 100% RH, its correspondingOutput is 0 100mV 1. According to the integrated amp with phase ratio amplification gain: Kf=R1+ Rf =1+ 47 =48Then the output amplification V0 = 48 analog signal voltag
16、e, so output analog, Vi, electric pressure fan letter surrounded is 0 4.8v. This mode, turn into A/D CH0 slice of replace core general way into line changeover place, have cut to several words AT89S51 single-chip letter Numbers again into data processing and the LCD.3.2 A/D conversion chip choice an
17、d controlling principleThis article chooses A/D conversion chips for ADC0832, this chip is 8Pin double row straight insert dual channel A/D converter, can separately for both road simulation No real now believe d/a change, can use in the ocl lose into mode and bad points to loseUnder the way of DI s
18、erver channel selected choose, several according to adopt sets and Data transfer 2.The work of ADC0832 do sequence as shown in figure 3. Root according to our web site, when covariance .ADC0832 did not work, must the piece selected in the high level, the CSWhen chip disabled. When should undertake A
19、/D conversion shall be piece selected end CS offsetsIn low level and maintains to convert over. Chip began to work, still need to makeMonolithic machine to core chips, when the clock CLK lose faith in the clock pulse blunt when lose,In the first clock pulse before the sinking DI end must be high ele
20、ctric flat, tablesAnd start signal. In the first 2, 3 pulse sinking DI end before should be lostInto two data used to select channels function. Channels are as follows:(1) the controlled conditionsIn accordance with The Times when DI lost with 1, 0, the only way to do CH0 tong general turned into si
21、ngle wordChange; (2) when DI ordinal input 1, 1, only for single CH1 channel onTao transformation;(3) when DI ordinal 0, 0, will CH0 as is, will CH0 input 0 as its negative input IN CH1 -, as are the input IN +3.3 microcontrollers choiceMCU is the control of core, compared with the others ,we chose
22、AT89S51 single-chip microcomputer. The advantages of this type of single-chip microcomputer is 3 : (1) The single-chip microcomputer and the 8051 series microcontroller is fully compatible, make it use easily, and into the ten points Cheap; (2) Internal memory can be repeated CaXie by the EEPRROM, b
23、e helpful for repeatting modify the program;(3) has the low consumption working methods and to be achieved Off electrical automatic protection; (4) has strong anti-jamming, greatly improving the worthRoyal external electromagnetic interference ability, so it is especially suitable for relatively tou
24、gh in conditions Under the poor conditions of the job.3.4 The use of LCDUsing micro LCD display device, 1602LCD, its performance point is: working voltage only 4.5 5.5 V; Very low power consumption (work currentOnly 2.0 mA); And reliable work; Small volume (can show 16 x 2 wordsOperators). Its chara
25、cters are displayed by internal special displacement function of HD44780 dynamic core slice 4Quasi ASCII put into their number within department set into reservoir with deposit according to show and editor (DDRAM), inside the ministry accused of line of road will move will word from sheba operators
26、preach send to show, Implement. Monolithic machine and the number of 1602LCD between general P0 into change had to enter line, resistance for P0 mouth R9 R2 the pull-up resistorsSection 4 The software design of the control of systemThis recorder controlling software design adopts modular thought. Ac
27、cording to the function,w emake the controlling system software devide into two big modules: (1) ADC0832 driver module, to control the collection of voltage signal;(2) 1602LCD driver module, show soil humidity. This system driver using CLanguage design, its main program is as followsMain (void)unsig
28、ned int AD_val;Convert the value after theunsigned int Int, Dec;The converted the integer part and the decimal part/ / storage save A/D/ / points dont store in existencechangeLcdInitiate ();/ / to be liquid crystal early beginning2)the production of clock When the clock points frequency device (afte
29、r it can have to 4.5 MHz in turn when the change in A/D clock) turn change when idle is empty, the hold after A state in ADCR is written to the START field immediately START 01 (conversion) or the selected edge appear in choice of signal sampling clock can immediately START. This feature can save po
30、wer consumption. ADC conversion clock computation formula is as followsFADC=FPCK/（CLKDIV+1）Type: Fpclk - core slice; when the clock set After CLKDIV - points of ADC conversion clock frequency.3) interrupted. When DONE bits is 1, A/D conversion module to vector interrupt controller (VIC) issued an in
31、terrupt request in the VICIntEnable VIC, if Bit8 (A/D conversion interrupts enabled bits) make can, then can produce the interruption. Read ADDR will reset DONE bits. This paper mainly A/D acquisition C language driver section design is as follows:/* Function: A/D acquisitionEntrance parameters: CH_
32、i/*void AD_Change(unsigned char CH_i)ADC0R = (1 CH_i) | / / choose channels I carry A/D acquisition (Fpclk / 1,000, 000-1) 8 | / / set convert clock(0 16)(0 19)| / / BURST = 0, software control conversion operations| / / normal A/D acquisition modes(0 27);| / / decrease along the startup conversionA
33、D0DR; DO = / / read take ADC and fruit, and clear exceptDONE mark bitswhile (1).Section5 temperature measuring system of Proteus software simulationTo ensure system on the hardware and software system, reliable work the Proteus software simulation. The basic process is first draw HaoTu 3 illustrates
34、 the simulationElectricity by road after Keil soft thing, Ed into the translation and born of dynamic soft thing ec flooding (files) : LPC2131 loaded. And Proteus software environmentThe simulation results ( + 3V corresponding full amount 30Kpa) the process design of the software and hardware the re
35、sults show that the system is correctTo ensure that the design of the software and hardware of soil detector is correct this paper designs proteus soft thing into line imitation true. The base this process is first draw had made good figure 2 shows simulation circuit, Keil software compiled by again
36、 and to create system driver ( *. Wen pieces ) load: the monolithic machine, and will figure 2 virtual dc voltage signal generator set to 45mV. Then the simulation of voltage: enlarge V0 = 48 x 0.045 = 2.16 V, soil relative humidity should be: RH = 2.16 by 100 = 45% RH. Start the simulation can see
37、1602LCD in figure 2The simulation results show that the 45.18% RH (for the calculation and existing tinyAccording to convert error). The results show that the system software and hardware design are right.Section6 conclusionThis paper introduces some machine oxygen pressure detection adjustment syst
38、em design of the software and hardware square method. This set with set in A project into A/D turn changing mould pieces of high sexual can LPC2131 chip, tell the plus special A/D acquisition chip, simplified the peripheral circuit design. The system design is simple in structure, reliable in trial
39、has obtained good effect.(1) this design using highly integrated humidity detector A/D conversion chip, SCM and LCD module, greatly simplifying the hardware circuit and significantly reduce the size and cost of A circuit board.(2) electric pressure letter in ADC0832, integrating core piece of work i
40、s really is. EcThe most important premise, to ensure reliable of the analog signal collection, collection need before use integrated amp sensor signal amplifier.(3) the loam soil by small, measuring devices body product by pure degree is high and measured this very low, suitable to use of agricultur
41、al first production line. (4) the system can shorten Proteus simulation designing cycle, managing hardware investment. The simulation results show that the system design is correct, reliable operationSection 7 References1 孙余凯,吴鸣山,项绮明.集成运算放大器实用电路识图M.北京2 李赣平,邵惠鹤.基于 ARM 的高精度智能流量变送器的设计J3 冯伟,白瑞林,李祥伟.基于 W
42、inCE5.0 的数字式触摸屏驱动程序的开发J.自动化仪表, 2009,9.4 张洪润. 传感器应用设计 300 例（上册）M.北京: 北京航空航天大学出版社, 2006.5 徐玮. C51 单片机高效入门M. 北京: 机械工业出版社, 2007.6 师宝山.基于 AT89S51 的多参数气体检测仪的研制J.微计算机信息, 2007, 71.7 周坚.单片机轻松入门M.北京:北京航空航天大学出版社, 2004.基于 AT89S51 单片机的微型土壤湿度检测仪设计摘要： 为便于掌握土壤的湿度状况， 设计了微型土壤湿度检测仪。 其硬件系统包括信号放大电路、 A/D 转换电路、 单片机、 微型液晶显
43、示器和报警电路等； 软件系统包括 A/D 转换的驱动程序 、 液晶驱动程序两个模块。 基于 Proteus 软件平台对系统的设计进行了仿真， 结果表明系统的软硬件设计正确，运行可靠。关键词： 土壤湿度； 检测仪； 单片机； A/D 转换； 仿真中图分类号： TP202文献标识码： A第一章引言农业生产在我国的经济发展中具有重要地位，为农业生产提供及时、 可靠的技术服务已成为气象部门的重要职责之一 。 随着国家各级政府对农业生产的日益重视，我单位也在服务农业、 促进农民增收等方面开展了许多研究 ，对农业生产中的各项问题也进行了广泛调研.调研发现， 园艺栽培、温室花卉、大棚蔬菜等的某些名贵品种，对
44、土壤湿度有着极高的要求，土壤湿度不当时，不仅严重影响其正常生长，甚至会导致种植品死亡，造成农民的严重损失。为此，从事该类农业生产的农民朋友非常需要一种成本低、体积小且检测可靠的土壤湿度检测仪，为水分供应提供依据。为了解决以上问题，我单位结合我区农业生产实际状况，和有关单位专家共同设计了高精度 、低成本的微型土壤湿度检测仪 。本文则详细介绍了该检测仪的测控电路和相关软件流程。第二章系统的组成微型土壤检测仪的信号处理系统包括土壤湿度传感器、A/D 采集电路、单片机和微型液晶显示器。其工作过 程 是 ：土 壤 湿 度 传 感 器 将 湿 度 信 号 送 至 A/D 采 集 电路，经 A/D 转换后，
45、所得数字信号送入单片机进行数据处理，最后将处理结果发送到微型液晶显示器显示。第三章 系统的硬件设计3.1 电路的工作原理本文所选的KSC-6V集成相对湿度传感器插入土壤后，等待约5s使传感器充分接触土壤后，信号 Vin 经集成运放 LM324 的同相输入端。该传感器的相对湿度 0%100%RH 时，其对应的输出为 0100mV1。根据集成运放的同相比例放大增益：Kf=R1+ Rf =1+ 47 =48则放大后的输出模拟信号电压V0=48?Vi，故输出模拟信号电压范围为 04.8V。该模拟信号进入A/D 转换芯片的CH0 通道进行转换处理，所 得到数字信号再送入单片机 AT89S51 进行数据处
46、理并由液晶显示。3.2 A/D 转换芯片的选择与控制原理本文选择的 A/D 转换芯片为 ADC0832，该芯片为8引脚双列直插式双通道 A/D 转换器，能分别对两路模拟信号实现 模/数 转换，可以用在单端输入 方式和差分输入方式下工作，其中DI端进行通道选 择、数据采集和数据传送2。ADC0832的工作。根据协议，当ADC0832 未工作时，必须将片选端 CS 置于高电平，此时芯片禁用。当要进行A/D 转换时，应将片选端CS置于低电平并保持到转换结束。芯片开始工作后，还需让单片机向芯片的时钟信 号输入端 CLK 输入时钟脉冲，在第一个时钟脉冲的下沉之前 DI 端必须是 高电平，表示起始信号。在
47、第2、3个脉冲的下沉之前DI 端则应输入两位数据用于选择通道功能。通道受控情况如下： 当DI依次输入1、0 时，只对CH0通道进行单通道转换；当DI依次输入1、1 时，只对CH1通道进行单通道转换；当DI依次输入0、0 时，将CH0作为正输入端 “IN+”，CH1作为负输入端“IN-”；当DI依次输入 0、1 时，将CH0作为负输入端“IN-”，CH1作为正输入端“IN+”。在第 3 个脉冲下沉之后，DI 端的输入电平就失去输入作用 ，此 后数据 输出端DO开始输出转换后的数据 。在第4个脉冲的下降沿输出转换后数据的最高位，直到第11个脉冲下降沿输出数据的最低位，至此 ，一个字节的数据输出完成。正常情况下，ADC0832 与单片机的接口应为4条数据线，分别是CS、CLK、DO、DI。但由于 DO 和 DI两个端口在通信时并未同时使用，而是先由DI端口输入两位数据（0 或 1）来选择通道控制，再由DO端输出数据 。因此，在I/O 口资源紧张时，可以将 DO 和并联在一根数据线上使用。3.3 单片机的选择单片机是控制记录仪工作的核心