外文翻译-基于AT89C2051 的智能型汽车防撞报警器的设计
基于AT89C51单片机倒车防撞报警系统设计2
基于AT89C51单片机倒车防撞报警系统设计目录一、前言 (4)二、系统组成及工作原理 (4)三、系统硬件电路的设计 (5)（一）超声波发射与回波接收电路 (5)（二）超声波电信号放大电路 (5)（三）单片机控制电路和显示、报警电路 (6)四、系统软件的设计 (6)（一）主程序 (6)（二）T0中断服务程序 (8)（三）外部中断0服务程序 (9)（四）超声波发生子程序 (9)五、实现应用分析 (9)六、结语 (10)致词 (10)参考文献 (12)摘要介绍基于单片机控制的倒车雷达系统，该系统采用通用型单片机作为控制电路，方便系统功能扩展。
系统电路主要采用集成器件构成，外围元件少，电路简洁、调试方便、成本低，利于商品化生产，本系统充分利用了单片机的内部资源，用软件编程产生超声波矩形脉冲，代替硬件的超声波发生电路，节省了硬件成本。
关键词：LED数码管、蜂鸣器、倒车雷达、脉冲电压、AT89C2051单片机AbstractIntroduced based on single chip microcomputer control system, the system of reverse radar using universal model microcontroller as the control circuit, convenient system function expansion. System adopts integrated circuit main components, peripheral devices, simple circuit, commissioning, low cost, convenient for commercial production, this system makes full use of the internal resources, with MCU software programming in rectangular pulse, instead of producing ultrasonic wave occurs, the hardware circuit hardware cost saving.KEY WORDS: Led numerical codes tube、 buzzer、Back-draft radar、Pulse voltage、At89c2051 monolithic integrated circuits一、前言汽车倒车防撞预警系统即是俗称的倒车雷达，是汽车泊车辅助装置。
基于AT89C2051的智能型汽车防撞报警器的设1概要
基于AT89C2051的智能型汽车防撞报警器的设计引言：介绍了AT89C2051单片机的性能及特点，及以其为核心的一种低成本、高精度、微型化、数字显示的汽车防撞报警器。
该防撞报警器利用超声波及集成霍尔元件实现对汽车的测距和测速，利用单片机的实时控制和数据处理功能，完成系统的控制。
文章给出了报警器的硬件电路原理及软件设计。
随着现代生活节奏的加快，交通事故发生的频率也在增加，为提高汽车运行的安全性，本文介绍一种单片机控制的汽车防撞报警系统。
该装置将单片机的实时控制及数据处理功能，与超声波的测距技术、传感器技术相结合，可检测汽车运行中后方障碍物与汽车的距离及汽车车速，通过数显装置显示距离，并由发声电路根据距离远近情况发出警告声。
二：超声波的简介我们知道，当物体振动时会发出声音。
科学家们将每秒钟振动的次数称为声音的频率，它的单位是赫兹。
我们人类耳朵能听到的声波频率为20～20，000赫兹。
当声波的振动频率大于20000赫兹或小于20赫兹时，我们便听不见了。
因此，我们把频率高于20000赫兹的声波称为“超声波”。
通常用于医学诊断的超声波频率为1～5兆赫兹。
超声波具有方向性好，穿透能力强，易于获得较集中的声能，在水中传播距离远等特点。
可用于测距，测速，清洗，焊接，碎石等。
在医学,军事,工业,农业上有很多的应用。
理论研究表明,在振幅相同的条件下,一个物体振动的能量与振动频率成正比,超声波在介质中传播时,介质质点振动的频率很高,因而能量很大.在我国北方干燥的冬季,如果把超声波通入水罐中,剧烈的振动会使罐中的水破碎成许多小雾滴,再用小风扇把雾滴吹入室内,就可以增加室内空气湿度.这就是超声波加湿器的原理.咽喉炎.气管炎等疾病,呼唤斤年时斤百很难血流到达患病的部位.利用加湿器的原理,把药液雾化,让病人吸入,能够提高疗效.利用超声波巨大的能量还可以使人体内的结石做剧烈的受迫振动而破碎，从而减缓病痛，达到治愈的目的。
超声波的产生声波是物体机械振动状态（或能量）的传播形式。
精品中英文外文翻译基于单片机的汽车防盗报警系统设计定
Based on monolithic integrated circuit automobile security alarmsystem designAbstract:Decodes the automobile security system using them on litchis integrated circuit interior resources realization jump code, it each time uses the remote control password all is changing, both enhanced the system security, and greatly reduced the cost.Keyword: Monolithic integrated circuit, Automobile security system , Code/decodeIntroductionIs unceasingly progressive along with the social economy and the high tech rapid development, in the routine work and the life, the automobile has become the people ideal transportation vehicle. But the following motor vehicle the case which robbed gradually is also in creased has created the pilot economical property loss. In order tore duce the automobile to rob the event the formation rate, for has the automobile the user to provide the safety control, simply develops one kind to be reliable, the ease of operation, can send out in the discovery normal condition to the pilot reports to the police the reminder and the security warning safety system has the practical significance. This article based on to the existing automobile security alarm system generalized analysis, develops one kind of brand-new security alarm system. This system has mainly used the jump code code/decoding principle, causes the overall system to be safer, greatly reduces password explaining rate.1. System principle of workThe automobile security alarm system the remote control which carries by the driver and installs in the automobile the controller two parts composes. The remote control and the controller all use eight CMOS which American AT-MEL Corporation produces the A VR monolithic integrated circuit, this series monolithic integrated circuit based on new simplifies instruction R the ISC structure, includes the service life most to be few is 1,000 time writes/scratches the circulation the Flash program memory, as well as the service life at least is 100,000time writes/scratches the circulation E the EPROM data-carrier storage, some 2 only have when the entire piececleaning can clean the programming encryption locks the localization.1.1 System designThe automobile security examination uses the ultrasonic sensor. The ultrasonic sensor is composed by the ultrasonic wave transmission circuit and the supersonic reception electric circuit, in the automobile cab appropriate position, installs the ultrasonic wave launch/receiver, as well as switch electric circuit T1. When the automobile parks the vehicle owner person must leave the automobile, with remote control closed switch T1, the automobile alarm system sat garrisons the condition, around the system use ultrasonic wave examination vehicle obstacle. Launches the partial electric circuits likes chart 1 to show. When its P1 mouth P1.1, P1.2 to the D trig , the P1.0 control ultrasonic wave launch, are 0, the photo electricity coupler outputs the TP1 end is 1, the permission ultrasonic wave launch, launches/the receive ultrasonic wave in turn, the circulation repeatedly carries on. Simultaneously the monolithic integrated circuit interior counter starts to count. The steam distance between vehicles obstacle distance is the time which sends out through the sound navigation and ranging reflects spends determines and carries on the computation. The reflection signal causes the D trigger to produce interrupt request signal INT1,simultaneously stops counting, reads takes counts the value, calculates the actual distance after the formula, then carries on the comparison with the datum distance, if examines when the actual distance is bigger than reference value 80cm, does not carry on the accustom-optics to report to the police; If some people approach the automobile to enter the cab, the examination actual distance is smaller than or was equal to when reference value 80cm, through monolithic integrated circuit P2.2 and the P2.3 port, actuates the indicating lamp display circuit and the sound alarm circuit, sends out three two flash. And triggers a high level, the actuation is wire less signal transmission circuit.Chart 1 Ultrasonic wave transmission circuit1.2 Code/decoding principleThe present automobile remote control security system are many isusesVD5026/27, PT2262/72, HT12E/D and so on the general code/decodes the electric circuit, its password decided by the component address, each set of security systems use a fixed invariable password. Along with the micro processing technology development, through the receiver emote control transmitting message, may intercept this fixed password, moreover general arranges the decoding address to lose the person to carry the component size limit, its quantity is impossible too much, can obtain not repeatedly codes very is also limited, also can very quickly explain the password with the automatic scanner. Therefore, this kind of password fixed invariable automobile security system has received the serious threat. Decodes the automobile security system using the monolithic integrated circuit interior resources realization jump code, it each time uses the remote control password all is changing, with the password no longer duplicates uses, causes the interception password also is makes a futile effort, in addition, it may increase the enough many passwords figure, enhances the system resistance illegal scanning the ability. The remote control coding altogether has 12 bytes, separately by 3 bytes codes channels code, 3 bytes codes forewords number, 5 bytes jumps codes, 1 byte pressed key operation code is composed. Encoded front adds on logic in each byte 0 to take the outset position, encoded behind adds on a logical 1 achievement in each byte to stop the position, and in most front adds on several logic 1 to take the guidance signal, this constituted the serial coded signal which uses in to transmit. The code channel code uses in to express the remote control status; each set of systems use a fixed channel code. The code foreword number uses in to record the encoded order, its starting value is 0, the monolithic integrated circuit every time codes a time, the code foreword number upwardly counts time. The code channel code and the code foreword number deposits in monolithic integrated circuit EEPROM, guarantees them power cut the influence. The jump code is the systematic true password, it passes through the complex special algorithm by the code channel code and the code foreword number to extract, this special algorithm foreign security. The pressed key operation code by the pressed key which presses was decided, when "the hypothesis" the key is pressed down, its code decides as 0 1H; When "relieves" the key presses down, its code decides as 00H. Whether is the decoding confirms receive the code legitimate a series of operating process. Was confirmed the legitimate code needs to satisfy three conditions; (1) codes the channel code and the decoding channel code is same; (2) coded the foreword number to be bigger than the decoding foreword number (decodingforeword number to record on legitimately has used code foreword number, this condition might guarantee before has used code was invalid); (3) jumps the code to be equal to reuses the special algorithm to extract changes the code. After the monolithic integrated circuit confirmed receives is the legitimate code, writes the code foreword number in the decoding foreword number, and completes corresponding operation processing according to the operation code. The decoding channel code and the decoding foreword number also deposits in monolithic integrated circuit EEPROM, guards against because of power cut loses.1.3 Security reports to the police realizationIf will have robber Chen ZheRu the room, starts the automobile, after wrong password, then the automobile storage battery +12V voltage, the ignition electric current way ignition lock, the ignition outage, the engine extinguishes, again starts, will duplicate the above process, like this, the bandits and thieves always will not be able to start the automobile, will not be able to achieve its anticipated goal. The alarm circuit mainly is composed by the integrated block and the speaker and electronic switching SCR. Triode or the multiple-unit tube, are for enhance the electric circuit measure which the power but often uses, it has composed a current amplification factor very big equivalent transistor, total enlargement factor for these two enlargement factor product. SCR is the electronic switching which constitutes by the silicon-controlled rectifier, the electric capacity and the resistance constitution negative booster concurrently filter, provides +3 +4V to IC the voltage, IC is traces Draws up sound reports to the police the integrated circuit, the alarm apparatus by the SCR control, robs the vehicle thief once after the wrong password, then the storage battery electric current enters the security system besides a group, another group is started in the engine, after leads the engine work, natural contact output voltage, after the differentiating circuit, silicon-controlled rectifier SCR is triggered, also passes through the resistance to fall the pressure, the voltage adds in the IC power source input end, IC obtains the voltage output alarm, enlarges after the multiple-unit tube, Destroys moves the speaker to send out resoundingly reports to the police the sound. when static state, entire electric circuit does not consume the electricity.2. Software designThe alarm apparatus software design mainly divides into:Master routine (alarm apparatus initialization, key modulation and decoding); Alarm apparatus interrupthandling routine. This alarm apparatus installs on the automobile steering wheel. After installs, starts the alarm apparatus, the alarm apparatus automatically retards20~30s to start to work, in order to lets use the person to have the enough time to lock the gate to leave the automobile. After the time delay the alarm apparatus enters the value to defend the active status, once the vehicle door is turned on or the windowpane hits garrulously, the oscillation pick-up examines the signal, time delay 20s starts to report to the police. The time delay goal is the master which causes the automobile is opening the gate to enter the vehicle internal energy closure alarm apparatus, in order to avoid reports to the police by mistake.2.1 Master routineThis part mainly completes to each severance entrance hypothesis, and reports to the police the depositing unit initialization to each fixed unit, establishes the special symbol value and to the pressed key interrupts processing. Master routine design diagram like chart 2 shows.Chart2 master routine frame chart2.2 Alarm apparatus interrupt handling routineThe burglar alarm disposal procedure uses time severance inquiry processing, each time severance, only is inquires each kind of control flag bit, controls each group output according to its condition. The procedure has not used has circulation processing the way, therefore time control conclusion, cannot eliminate controls the flag bit, only is repositions the scene, the waiting next time severance, again judges whether controls the conclusion.3. Concluding remarkUses automobile security alarm system cost which this kind of monolithic integrated circuit composes low, performance reliable, simultaneously settles the extension to be convenient. The use jump code code/decoding principle, causes the system to be safer, greatly reduces password explaining rate, will obtain the wide spread application in the future automobile security alarm system.基于单片机的汽车防盗报警系统设计摘要:应用单片机内部资源实现的跳变编码/解码汽车防盗系统，它每次使用的遥控密码都在变化，既提高了系统的安全性，又大大降低了成本。
基于AT89C2051 的智能型汽车防撞报警器的设计中英文资料
An AT89C2051 Based Intelligent Proxim ityWarning Indicator for Automobile It introduces the function and characteristicsofm icrocontrollerAT89C2051 Based on it. A low cost high-accuracy microm iniaturization and digital display proxim ity warning indicator for automobile is designed. The indicatormeasures the distance and speed of the automobile, with ultrasonicwave and integrated Hall unit and controls the system by the real-time control and Data-processing of the microcontroller Moreover. its circuitry principle is introduced in detail as well as its software design.Along with modern rhythm of life speeding up, the frequency which the traffic accident occurred is increasing, for enhances the security of automobile movement. This article introduced one kind of alarm system based on monolithic integrated circuit controls the automobile guards against hitting. This equipment the monolithic integratedcircuit real-time control and the data processing function, with the ultrasonic wave range finder technology, the sensor technologyunifies, may examine in the automobile movement rear area the obstacle and the automobile distance and the automobile vehicle speed, reveals the installment demonstration distance through the number, and is away from far and near the situation by the sound production electriccircuit basis to send out the warning sound.The ultrasonic ranging principle is, after unceasingly examines the ultrasonic wave launch to meet the echo which the obstacle reflects, thus determines the launch ultrasonic wave and receives the echo the time difference. Then extracts is away from S=C×T/2, C is the ultrasonic wave wave velocity, under the normal temperature takes is 344 m/s. After sonic speed determination, so long as obtains the ultrasonic wave round-trip the time, then obtains the distance.The automobile vehicle speed survey is integrates the sensor through Hall to realize. Namely, is loaded with the permanent magnet the turntable input axis and the wheel revolution axis is connected, when the wheel rotates, the turntable along with it rotation, this time, on the turn table permanent magnet can integrate the sensor after Hall, thus integrates the sensor in Hall the input end to obtain a magnetism signal, if the turntable does not stop the rotation, Hall integratesthe sensor then to be able to output the rotational speed signal. It can be said that, to the automobile vehicle speed survey essence into the rotational speed signal frequency survey.AT89C2051 is a low power loss, the high performance 8 CMOS microprocessor, is compatible with the MCS-51 series instruction collection and the pin, has following characteristic: 128 bytes internal RAM, 2 K bytes EPROM, fifteen I/O line, two sixteen-fixed time counters, five two-level of interrupt sources, one entire duplex serial port, internal precisely simulates the comparator and internal swingming, the low power loss leaves unused and falls the electricity pattern. The working voltage scope 4.25 ~ 5.5 V, the operating frequency takes12 MHz.In AT89C2051, two sixteen-fixed time/counters registers is T0and T1, make fixed time/counters, may count the machine cycle, counts the frequency for the oscilation frequency 1/12; When makes the counter, may appears to on exterior input pin P3.4/T0 and P3.5/T1 from 1 to 0 changes when increase 1, counts the frequency for the oscilation frequency 1/24.This alarm apparatus is made up of the control system, the ultrasonic wave transmission circuit, the accepting circuit, measured the fastelectric circuit, the alarm circuit, the LED display circuit etc.The ultrasonic wave launch electricity route CC7555 time base circuitand the ultrasonic wave launch pokes head into compose. The monolithic integrated circuit AT89C2051 pin controls the P1.7pin to control the CC7555 time base circuit to produce the 40kHz frequency code for the ultrasonic generator, pokes head in the ultrasonic wave Launch obstacle by the ultrasonic wave which launches. Has the characteristic below using the ultrasonic ranging: high survey sensitivity, strong penetrating power, quick survey speed, the big survey angleis, in the correlation wide range object carries on the examination.The supersonic reception electric circuit is composed of pokes head in, the amplifier band the shaper circuit. The ultrasonic wave reflects which by the obstacle pokes head in after the receive, to transform for the electricity pulse signal, again after the amplifier, the shaper enlargement and the reshaping sends in the P3.2pin. of AT89C2051. The amplifier suitably selects has the enough gain and the lower noise wide band amplifier, maintains the pulse signal fron tnot to have the distortion in particular, enhances the range finder the precision.Measured the fast electric circuit is composed of the sensor, the pulse amplifier, the shaper, the CC7555 time base signal circuit, the gate. Hall integrates the sensor to turn the wheel rotational speed signal the pulse signal output, after the enlargement, the reshaping electric circuit sends in the gate, produces unit time base signal control gate opening by the CC7555 time base circuits with to shut, controls the rotational speed signal in the unit time through the gate, sends in monolithic integrated circuit the P3.5 pin of AT89C2051, controlled theT1 counter to count, has realized in unit time counting.The alarm circuit is composed of the CC7555 electric circuits and the speaker. The P1.6 pin of AT89C2051 controls the CC7555 electric circuit basis measurement result, produces the certain frequency signal actuation speaker to send out reports to the police the sound. Sends out when the speaker reports to the police the sound, time base circuit CC7555 is in temporarily the stable state, this time power source to electric capacity charge, thus causes CC7555 to end temporarily the stablestate to reply the steady state, outputs the low level, causes the speaker to stop sending out reports to the police the sound, produces newly until the next range finder conclusion reports to the police the sound.The LED display circuit is composed of the digital tube and the actuation electric circuit. With two digital tubes demonstration distance, the digital tube uses the static state to demonstrate that, by the chip MCS14495 actuations demonstrations, P1.4, P1.5 separately saves the signal as the actuation chip MCS14495 locks, uses in BCD which controls produces (Binar Code Decimal), the binarycode expression tens digit is demonstrates the top digit or the lowposition.The AT89C2051 mainly completes the procedure the execution,data processing and to exterior electric circuit real-time control.Internal timer T0 work in fixed time way, when ultrasonic wave launch starts to count, after pin P3.2receives the echo,stops counting, T0 times namely for the ultrasonic wave round-trip transmission time, the monolithic integrated circuit carries on processing to this data, then determines the distance.The internal timer T1 work is counting the way, counts by P3.5 pin input pulse signal control T1, counts the value by T1 to determine the automobile the rotational speed. The monolithic integrated circuit basis measured is away from and the vehicle speed carries on thecomparison, judges whether actuates the alarm circuit to report to thepolice, like hypothesis: When the vehicle speed is smaller or equal to 30km/s, the safe distance should be bigger than is equal to 1m; When the vehicle speed is smaller or equal to 80 km/s, the safe distance should be bigger than is equal to 2m; When the vehicle speed is bigger than 80 km/ s, the safe distance should bebigger than is equal to 5m .This installment control software must complete the system initialization, the control trigger pulse signal launch and the receive, according to fixed time the count-down obstacle distance, according to counts the frequency computation automobile vehicle speed, judges measured is away from whether in the margin for safety which the vehicle speed corresponds, and according to calculates has the BCD code and the corresponding frequency pulse signal with the judgement result, actuates the display circuit and the sound production electric circuit基于AT89C2051 的智能型汽车防撞报警器的设计本文介绍了AT89C2051 单片机的性能及特点，及以其为核心的一种低成本、高精度、微型化、数字显示的汽车防撞报警器。
一种基于AT89C51的汽车倒车防撞报警系统的设计
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基于AT89C51单片机倒车防撞报警系统设计中英翻译
Ultrasonic wave examination development summaryThe high velocity, the high efficiency is the modern industry symbol, but this is the establishment above the high grade foundation. The design and the craft personnel should understand that,Must a organizational structure, stochastically has microscopically, the macroscopic flaw, may sometimes even be frequently only can depend upon not damages the examination technology the utilization only then to give to discover, appraisal. Certainly, this with dozens of year in every way value and the general jobholders' difficult endeavor, causes not to damage the examination technology to have certain ability in this aspect to concern. Now, in the industry developed country, not damages the examination in the product design, the development, the user departments already by the fruitful utilization, in 1981 American former president Reagan in not damaged the examination academic society 40th anniversary congress to US in the letter of congratulations to say: “You can give the airplane and the spatial flight vehicle, the power plant, the ships, the automobile and the building and so on bring a greater degree the reliability. Not has not damaged the examination, we not impossible to enjoy at present in these domains and other domain leading status.”Not damages the examination by the swift and violent potential to the depth development, the objective need is after all the biggest power which one specialty may develop.Our country not damages the examination technology is grows out of nothing, develops gradually from the lower stage to the application popular present stage level. Ultrasonic wave instrumentation development production, also presses this rule development change approximately.The 50's, our country starts from the overseas introduction ultrasonic wave instrument, many is the unwieldy electronic tubular instrument. If England's UCT-2 ultrasonic wave instrumentation, reaches 24Kg again, various units do the experimental study work positively, has obtained the good effect in some project examination.At the end of the 50's at the beginning of 60's, the domestic scientific research unit imported Poland to produce the ultra acoustimeter, and carried on the imitation production. Afterwards, Shanghai Tongji University develops the CTS-10 nonmetallic supersonic instrumentation, also is the electron tubular, instrument heavy approximately 20Hg. This instrument performance is stable, the profile is clear. But at that time this kind of instrument only then the individual scientific research unit used, the construction work department used not not many. Until 70's intermediate stages, because not damaged the examination technology still to be at the experimental stage, the promotion has not popularized, therefore the instrument big development, still has not used the electronic tubular UCT-2,CTS-10.In 1976, after National Construction committee Office of Sciences managed holds the nation architectural engineering examination technology meeting, National Construction committee not damaged the concrete the examination technology to list as the key attack project, the organization nation 6 unit cooperation attack. Henceforth, not damages the examination technology to start to enter has the plan, has the goal research stage. Along with the electronics industry rapid development, the transistor unit has replaced the electron tube component gradually, is moreadvantageous to not damages the examination technology the promoted popularization. If the Romanian N2701 ultrasonic wave reflectoscope reflector, is composed by the transistor discrete component, has the profile and the numerical code demonstrated, instrument weight 10Kg. The 70's, English C.N.S Corporation promotes only has the 3.5Kg heavy PUNDIT portable ultra acoustimeter.In October, 1978, Chinese Construction Academy of science developed JC-2 portable ultrasonic wave instrumentation. This instrument uses the TTL line, the numerical code demonstrated that, the instrument weight is 5Kg. Develops same time the supersonic instrumentation also has SC-2, CTS-25, SYC-2 ultrasonic wave instrumentation. Henceforth, our country had the ultrasonic wave instrument which own produce, not damaged the examination technology for the promoted application to lay the good foundation.The ultrasonic wave examination technology is our country prioritize and the promoted new technology, it has the high accuracy, not damages, merits and so on non-contact. At present, already widely applied at the machine manufacture, the electronic metallurgy, the navigation, the astronavigation, the petroleum chemical industry, industry domains and so on transportation. In addition, in the materials science, the medicine, domains and so on in biological science also occupies has the important status. Overseas was enhancing the ultrasonic ranging aspect to do the massive research, the domestic some scholars have also done the correlation research. Mainly is decided to the ultrasonic ranging precision by the ultrasonic propagation time and the ultrasonic wave which measured in the medium propagation velocity, in the two the propagation time precision influence is big, therefore the majority of literature use reduce the propagation time the uncertainty to increase the range finder precision. At present, the phase survey law and the sound spectrum outline analytic method or the two unify the method is main reduces the survey transmission uncertainty the method.The ultrasonic wave examination technology took not damages one of examination technology important methods, is playing the vital role in its developing process, it has provided the appraisal solid state material microscopic organization and the correlation mechanics performance, examines its microscopic and the macroscopic discontinous effective general method. As a result of its signal high-frequency response, the ultrasonic wave examination early time only uses the simulation quantity signal the analysis, the majority of check-out facility only has the A scanning form, needs through experienced not to damage examines the personnel to carry on the artificial analysis to the signal to be able to draw the correct conclusion, to examines is high with analysis staff's request, therefore, the human factor is big to the examination result influence, the profile not easy to record and the preservation, is not suitable completes the automated examination.The 80's later periods, as a result of the computer technology and the high speed component unceasing development, make the ultrasonic wave signal the digitization to gather and possibly to analyze into. At present domestic also one after another appeared each kind of digitized ultrasonic wave check-out facility, and has become the ultrasonic wave examination the development direction. Xiamen University's some scholar has studied one echo outline analytic method. This method seeks the echo enveloping curve in the range finder through two surveys to obtain the echo beginning, after like this processed the ultrasonic propagation time precision to obtain the very big enhancement. Italy's Carullo et al. introduced one kind of self-adaptive system, uses the special launch profile to obtain the good echo envelope, simultaneously uses to the ambient noisecarries on the estimation, establishes certain echo Kaiping electric circuit, also uses the automatic gain the control amplifier, enhances the ultrasonic wave through these measures the survey precision. Moreover, also has the massive literature research to use the digital signal processing technology and the wavelet transformation theory enhances the transmission time the precision. These processing method has all obtained the good effect.At present domestic and foreign all turns towards the digitized direction in the ultrasonic wave examination domain to develop, the digital ultrasonic wave instrumentation development speed is very quick. The home also one after another appeared many digital ultrasonic wave instruments and the analysis system in recent years. On international takes extremely to the ultrasonic wave examination digitization technology research, the overseas production similar product and the research company has US's Pan-America (PANAMETRICS) Corporation, METEC Corporation, Canada's R/D TECH Corporation, Germany's K-K Corporation, France's SOFRATEST Corporation and Spain's TECNATOM Corporation and so on, the above these companies produce ultrasonic wave examination gathering, the analysis and the image formation processing system technical level is high, is in the leading level in the world.Along with examination engineering research unceasingly thorough, is more and more high to the supersonic instrumentation function request, the single numerical code demonstrated the supersonic examination instrumental measurement reads can bring the big test error. Further requests the ultra acoustimeter which later will produce to be able to have double reveals and the inner tube has the single trigger micro processing function. Afterwards has the examination, the record, the memory, the data processing and the analysis and so on many function intellectualized examination analyzer develops one after another successfully. The ultra acoustimeter development presents a prosperous scene. Among them, the coal academy of science develops 2000A supersonic analysis instrumentation, is one kind of inner tube microprocessor intellectualization metering equipment, operates completely all is in the microprocessor under the control management, all observed values, the processing result, the condition information all demonstrated on the teletron, and may meet the miniature printer printing. Its numeral and the profile quite are all clear stably, the operation is simple, the reliability is high, has the power failure memory function, its serial port may facilitate the user to carry on the post-processing and the related procedure development to the instrument test data. Compares with the domestic similar product, design novel reasonable, the function is complete, has the significant breakthrough and the innovation in the instrument design, has achieved the international advanced level.At present, the computer market price large scale drop, uses the non-integrated ultrasonic wave instrumentation, the computer may display an it machine multipurpose each kind of function, in fact is biggest economy. In the past that kind of entire function instrument establishment, the might as well independent ultra acoustimeter, the computer might display respective characteristic fully. The high intellectualization instrumentation only can satisfy the examination condition, the use environment, the duplicated test content and so on the basic situation is same, only then may display its unique function fully. The instrument design also should embark from the actual situation, can satisfy the user the request. In summary, our country ultrasonic wave instrument development and the production, has develops greatly, some models have surpassed the overseas similar instrument超声波检测发展综述高速度，高效率是现代工业的标志，而这是建立在高质量的基础之上的。
AT89C2051微处理器在汽车倒车防撞报警器的应用
兼容ＭＣＳ５ｌ指令系统 １５个双向Ｉ／Ｏ口 两个１６位可编程定时／计敷器 时钟频事０－－２４Ｍｌｉｔ 两个外部中断源 可直接驱动ＬＥＤ 低功耗睡眠功能 可编程ＵＡＲＬ通道
２ｋ可反复擦写（＞１０００次）Ｆｌａｓｈ ＲＯＭ ６个中断源 ２．７·６．Ｖ的宽工作电压范围 １２８ｘ８ｂｉｔ内部ＲＡＭ 两个串行中断 两缀加密位 内置一个模拟比较放大器 软件设置睡眠和唤醒功能
ＡＴ８９Ｃ２０５ １徽处理ቤተ መጻሕፍቲ ባይዱ在淹车倒车防撞报警器的应用
赵文龙１，李立斌２
（１．广东工贸职业技术学院。 广东广州 ５１０５１０；２．广东技术师范学院天河学院。 广东广州 ５１０５４０）
ｌ引言
本文介绍了一种单片机控制的汽车防撞报警系统。该 装置将单片机的实时控制及数据处理功能与超声波的测距 技术、传感器技术相结合，可检测汽车运行中后方障碍物 与汽车的距离及汽车车速，通过数显装置显示距离，并由 发声电路根据距离远近情况发出警告声。
篇。
（缡辑：王智圣）
（上接第６ｌ页）
６结论
电镀电源工况环境复杂恶劣，且是行业资源消耗大户。 本文利用电流增强原理，设计了一种带辅助网络的零电压全 桥软开关电路拓扑，采用ＤＳＰ为核心芯片，充分利用其片上 资源，有效实现了对开关电镀电源的全数字化控制。并可通 过芯片集成ＣＡＮ总线模块实现电镀电源的集群控制，满足 了电镀行业对节能增效、绿色环保及设备数字化、智能化的 不断追求。最后通过实验验证了此设计的可行性与正确性。 ◆考文献： ［１】杜贵平。姜立新．电饺电源的现状反展望［Ｊ】．新技术新工
点：测量灵敏度高、穿透力强、测量速度快、测量角度 大，可对较大范围内的物体进行检测。
超声波接收电路由超声波接收探头、放大器和整形器 组成。由障碍物反射回来的超声波经接收探头，变换为电 脉冲信号，再由放大器、整形器放大和整形后送入到单片 机Ａ１瞰圯２０５ｌ的Ｐ３．２引脚。放大器宜选用有足够增益和 较低噪声的宽带放大器。以保持脉冲信号尤其是信号前沿 不发生畸变，以提高测距的精度。
基于AT89C2051的汽车超声波防盗报警系统设计
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１ 报 警 系 统 工 作 原 理
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基于单片机的汽车倒车防撞报警器开题报告
基于单片机的汽车倒车防撞报警器开题报告开题报告内容与要求一、毕业设计（论文）内容及研究意义（价值）设计的内容是基于AT89C51单片机倒车防撞系统的设计，主要是利用超声波的特点和优势，将超声波测距系统和AT89C51单片机结合于一体，设计出一种基于AT89C51单片机的倒车防撞报警系统。
该系统采用软、硬件结合的方法，具有模块化和多用化的特点。
此设计采用超声波测距原理，当汽车与障碍物的距离小于所设定的安全距离时，系统能发出声光报警，并随着距离的不断缩近，报警频率不断提高。
超声波测距仪器一般由发射器、接收器和信号处理器三部分组成。
工作时，超声波发射器发出超声波脉冲，超声波接收器接收遇到障碍物反射回来的反射波，准确测量超声波从发射到遇到障碍物反射返回的时间，根据超声波的传播速度，可以计算出障碍物距离。
随着我国经济的飞速发展，交通运输车辆的不断增多，由此产生的交通问题越来越成为人们关注的问题。
其中倒车事故由于发生的频率极高，已引起了社会和交通部门的高度重视。
倒车事故发生的原因是多方面的，倒车镜有死角，驾车者目测距离有误差，视线模糊等原因造成倒车时的事故率远大于汽车前进时的事故率，尤其是非职业驾驶员以及女性更为突出。
而倒车事故给车主带来许多麻烦，例如撞上别人的车、消防水笼头，如果伤及儿童更是不堪设想，有鉴于此，汽车高科技产品家族中，专为汽车倒车泊位设置的“倒车雷达”应运而生，倒车雷达的加装可以解决驾驶人员的后顾之忧，大大降低倒车事故的发生。
汽车倒车雷达全称为“倒车防撞雷达”，也叫“泊车辅助装置”，是汽车泊车安全辅助装置，能以声音或者更为直观的显示告知驾驶员周围障碍物的情况，解除驾驶员泊车和起动车辆时因前后左右探视所引起的困扰，并帮助驾驶员克服视野死角和视线模糊的缺陷，提高驾驶的安全性。
倒车雷达的原理与普通雷达一样，是根据蝙蝠在黑夜里高速飞行而不会与任何障碍物相撞的原理设计开发的。
通过感应装置发出超声波，然后通过反射回来的超声波来判断前方是否有障碍物，以及障碍物的距离、大小、方向、形状等。
基于AT89C2051的倒车防撞超声波报警系统
[导读]本文提出了一种基于AT89C2051组建单片机倒车防撞系统的设计方案，该方案主要是利用超声波的特点和优势，将超声波测距系统和AT89C2051单片机结合于一体，设计出一种基于AT89C2051单片机的倒车防撞报警系统本方案所设计的倒车防撞报警系统采用软、硬件结合的方法，具有模块化和多用化的特点。
设计中介绍了超声波检测的发展及基本原理，阐述了超声波传感器的原理及特性。
对于系统的一些主要参数进行了讨论，并且在介绍超声波测距系统功能的基础上，提出了系统设计的总体构成，本方案的提出将对汽车主动防撞乃至自动驾驶产生，给驾驶者提供一个倒车的操作指令。
1.引言众所周知，要检测两头之间是否有障碍物，一般的做法是一头发射一个信号，在接收处判断是否有信号接收到，若有信号接收到，说明中间没有障碍物；若接收不到，则说明有障碍物。
然而在汽车倒车防撞报警系统的设计中，由于汽车是一个移动的物体，不可能在某一具体的位置上安装接收或发射装置，这就决定了系统的发射与接收装置必须安装于一起，因此如何设计一款将发射与接收装置安装在一起的物体检测装置是我们的研究方向。
2.超声波测距系统介绍超声测距从原理上可分为共振式、脉冲反射式两种。
由于应用要求限定，在这里使用脉冲反射式，即利用超声波的反射特性。
超声波测距原理是通过超声波发射传感器向某一方向发射超声波，在发射时刻的同时开始计时，超声波在空气中传播，途中碰到障碍物就立即返回来，超声波接收器收到反射波就停止计时。
常温下超声波在空气中的传播速度为C=340m/s，根据计时器记录的时间 t，就可以计算出发射点距障碍物的距离（S），即：S=C*t/2 （1-1）可以看出其主要部分有：（1）供应电能的脉冲发生器（发射电路）；（2）使接收和发射隔离的开关部分；（3）转换电能为声能，且将声能透射到介质中的发射传感器；（4）接收反射声能（回波）和转换声能为电信号的接收传感器；（5）接收放大器，可以使微弱的回声放大到一定幅度，并使回声激发记录设备；（6）记录/控制设备，通常控制发射到传感器中的电能，并控制记录回波的时间、存储所要求的数据，并将时间间隔转换成距离。
毕业设计(论文)-基于AT89C51单片机倒车防撞报警系统设计
山西大学论文题目基于单片机倒车防撞雷达的设计研究学院工程技术学院专业电气工程及其自动化年级姓名指导教师职称副教授（2008年6月）学士学位论文（设计）原创性声明本人郑重声明：所提交的学位论文，是本人在导师指导下，独立进行研究工作所取得的成果。
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学位论文作者签名（亲笔）：年月日导师签名（亲笔）：年月日毕业设计（论文）评价表毕业设计说明书（论文）中文摘要毕业设计说明书(论文)外文摘要目录1引言 (1)1.1 倒车雷达研究的背景及意义 (1)1.2 国内外倒车雷达的发展现状 (2)1.3 雷达的发展 (2)2 超声波倒车雷达的工作原理 (3)2.1 超声波 (3)2.2 超声波发生器 (4)2.3 超声波测距原理 (4)2.4 超声波测距误差分析 (6)2.4.1 温度误差 (6)2.4.2 时间误差 (6)2．5 影响超声波探测的因素 (7)2.6 如何提醒车主 (9)3 系统设计 (9)3.1 倒车雷达的工作原理图 (9)3.2 系统硬件电路原理图 (11)4 系统硬件电路介绍 (11)4.1 AT89C51单片机 (11)4.2 电源部分 (14)4.3 放大电路 (17)4.4 音频解码电路分析 (18)4.4.1 LM567芯片介绍 (19)4.4.2 译码电路工作原理分析 (20)4.4.3 LM567在使用要注意以下几个方面 (21)4.5 声光报警电路 (21)5 系统软件设计 (22)5.1计算超声波传播时间 (22)5.2超声波发生子程序 (23)5.3超声波接收中断程序 (24)参考文献 (26)致谢 (27)1引言1．1 倒车雷达研究的背景及意义随着我国经济的快速发展，交通运输车辆及私家用车的不断增加，不可避免的交通问题瞬时成为人们关注的问题。
基于AT89C51的倒车防撞预警系统的设计
基于AT89C51的倒车防撞预警系统的设计
安永宁;李崇栋;金磊
【期刊名称】《机械工程与自动化》
【年(卷),期】2011(000)006
【摘要】介绍了一种以AT89C51单片机为主控芯片,基于超声波测距原理,能实现倒车防撞报警功能的系统,并提出了系统硬件和软件的设计方法.各功能电路采用集成芯片,减小了信号的相互干扰,提高了精度.该系统的最大测距误差不超过1 cm,测距范围为10 cm～300 cm,满足了倒车雷达的要求.
【总页数】3页(P121-123)
【作者】安永宁;李崇栋;金磊
【作者单位】中北大学,山西太原 030051;中北大学,山西太原 030051;中北大学,山西太原 030051
【正文语种】中文
【中图分类】TP277;U461.91
【相关文献】
1.基于AT89C51单片机倒车防撞预警系统设计 [J], 段永霞;徐杰;徐均
2.基于AT89S52汽车倒车防撞预警系统的设计 [J], 唐阳山;杨培菲;邱瑞;徐晓峰
3.一种基于AT89C51的汽车倒车防撞报警系统的设计 [J], 仇成群;孙东升;周殿凤;沈宏兰
4.基于AT89C51单片机的汽车倒车智能防撞系统设计 [J], 韩利凯;韩旭
5.基于单片机的倒车防撞预警系统设计和实现分析 [J], 袁秀珍
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基于AT89C51的倒车防撞预警系统的设计
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毕业论文---汽车倒车报警系统的设计(含外文翻译)
学士学位论文汽车倒车报警系统的设计目录摘要 (I)1 前言 (1)1.1论文设计的目的及意义 (1)1.2国内外的发展概况及存在的问题 (1)1.3论文的主导思想 (2)1.4系统设计中要解决的问题 (2)2 设计方案 (3)2.1 方案设计与论证 (3)2.1.1 控制芯片的选择 (3)2.1.2 测距传感器选择 (3)2.1.3 距离显示系统的设计 (4)2.1.4 声音报警设计 (4)2.2 系统的总体结构 (4)3 硬件电路设计 (5)3.1 主控单元设计 (5)3.1.1 主控芯片介绍 (5)3.1.2 最小系统 (7)3.1.2.1 复位电路 (7)3.1.2.2 晶振电路 (8)3.2 超声波测距单元设计 (9)3.2.1 超声波测距原理 (9)3.2.2 超声波发射电路 (10)3.2.3 超声波接收电路 (11)3.3 LED 距离显示器 (12)3.4 声光报警电路 (14)3.5 性能优化及改进 (15)4 软件程序设计 (17)4.1 主程序的设计 (17)4.2 中断处理程序设计程序 (17)4.2.1 定时中断程序 (17)4.2.2 外部中断程序 (19)5 结论 (21)5.1 设计成果 (21)5.2 展望 (21)参考文献 (22)致谢 (23)附录 (24)I汽车倒车报警系统的设计摘要：论文的内容是基于AT89C51单片机倒车防撞系统的设计，主要是利用超声波的特点和优势，将超声波测距系统和AT89C51单片机结合于一体，设计出一种基于AT89C51单片机的倒车防撞报警系统。
该系统采用软、硬件结合的方法，具有模块化和多用化的特点。
论文概述了超声波检测的基本原理，阐述了超声波传感器的原理及特性。
对于系统的一些主要参数进行了讨论，并且在介绍超声波测距系统功能的基础上，提出了系统的总体构成。
通过多种发射接收电路设计方案比较，得出了最佳设计方案，并对系统各个设计单元的原理进行了介绍。
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An AT89C2051 Based Intelligent Proxim ityWarning Indicator for Automobile It introduces the function and characteristicsofm icrocontrollerAT89C2051 Based on it. A low cost high-accuracy microm iniaturization and digital display proxim ity warning indicator for automobile is designed. The indicatormeasures the distance and speed of the automobile, with ultrasonicwave and integrated Hall unit and controls the system by the real-time control and Data-processing of the microcontroller Moreover. its circuitry principle is introduced in detail as well as its software design.Along with modern rhythm of life speeding up, the frequency which the traffic accident occurred is increasing, for enhances the security of automobile movement. This article introduced one kind of alarm system based on monolithic integrated circuit controls the automobile guards against hitting. This equipment the monolithic integratedcircuit real-time control and the data processing function, with the ultrasonic wave range finder technology, the sensor technologyunifies, may examine in the automobile movement rear area the obstacle and the automobile distance and the automobile vehicle speed, reveals the installment demonstration distance through the number, and is away from far and near the situation by the sound production electriccircuit basis to send out the warning sound.The ultrasonic ranging principle is, after unceasingly examines the ultrasonic wave launch to meet the echo which the obstacle reflects, thus determines the launch ultrasonic wave and receives the echo the time difference. Then extracts is away from S=C×T/2, C is the ultrasonic wave wave velocity, under the normal temperature takes is 344 m/s. After sonic speed determination, so long as obtains the ultrasonic wave round-trip the time, then obtains the distance.The automobile vehicle speed survey is integrates the sensor through Hall to realize. Namely, is loaded with the permanent magnet the turntable input axis and the wheel revolution axis is connected, when the wheel rotates, the turntable along with it rotation, this time, on the turn table permanent magnet can integrate the sensor after Hall, thus integrates the sensor in Hall the input end to obtain a magnetism signal, if the turntable does not stop the rotation, Hall integratesthe sensor then to be able to output the rotational speed signal. It can be said that, to the automobile vehicle speed survey essence into the rotational speed signal frequency survey.AT89C2051 is a low power loss, the high performance 8 CMOS microprocessor, is compatible with the MCS-51 series instruction collection and the pin, has following characteristic: 128 bytes internal RAM, 2 K bytes EPROM, fifteen I/O line, two sixteen-fixed time counters, five two-level of interrupt sources, one entire duplex serial port, internal precisely simulates the comparator and internal swingming, the low power loss leaves unused and falls the electricity pattern. The working voltage scope 4.25 ~ 5.5 V, the operating frequency takes12 MHz.In AT89C2051, two sixteen-fixed time/counters registers is T0and T1, make fixed time/counters, may count the machine cycle, counts the frequency for the oscilation frequency 1/12; When makes the counter, may appears to on exterior input pin P3.4/T0 and P3.5/T1 from 1 to 0 changes when increase 1, counts the frequency for the oscilation frequency 1/24.This alarm apparatus is made up of the control system, the ultrasonic wave transmission circuit, the accepting circuit, measured the fastelectric circuit, the alarm circuit, the LED display circuit etc.The ultrasonic wave launch electricity route CC7555 time base circuitand the ultrasonic wave launch pokes head into compose. The monolithic integrated circuit AT89C2051 pin controls the P1.7pin to control the CC7555 time base circuit to produce the 40kHz frequency code for the ultrasonic generator, pokes head in the ultrasonic wave Launch obstacle by the ultrasonic wave which launches. Has the characteristic below using the ultrasonic ranging: high survey sensitivity, strong penetrating power, quick survey speed, the big survey angleis, in the correlation wide range object carries on the examination.The supersonic reception electric circuit is composed of pokes head in, the amplifier band the shaper circuit. The ultrasonic wave reflects which by the obstacle pokes head in after the receive, to transform for the electricity pulse signal, again after the amplifier, the shaper enlargement and the reshaping sends in the P3.2pin. of AT89C2051. The amplifier suitably selects has the enough gain and the lower noise wide band amplifier, maintains the pulse signal fron tnot to have the distortion in particular, enhances the range finder the precision.Measured the fast electric circuit is composed of the sensor, the pulse amplifier, the shaper, the CC7555 time base signal circuit, the gate. Hall integrates the sensor to turn the wheel rotational speed signal the pulse signal output, after the enlargement, the reshaping electric circuit sends in the gate, produces unit time base signal control gate opening by the CC7555 time base circuits with to shut, controls the rotational speed signal in the unit time through the gate, sends in monolithic integrated circuit the P3.5 pin of AT89C2051, controlled theT1 counter to count, has realized in unit time counting.The alarm circuit is composed of the CC7555 electric circuits and the speaker. The P1.6 pin of AT89C2051 controls the CC7555 electric circuit basis measurement result, produces the certain frequency signal actuation speaker to send out reports to the police the sound. Sends out when the speaker reports to the police the sound, time base circuit CC7555 is in temporarily the stable state, this time power source to electric capacity charge, thus causes CC7555 to end temporarily the stablestate to reply the steady state, outputs the low level, causes the speaker to stop sending out reports to the police the sound, produces newly until the next range finder conclusion reports to the police the sound.The LED display circuit is composed of the digital tube and the actuation electric circuit. With two digital tubes demonstration distance, the digital tube uses the static state to demonstrate that, by the chip MCS14495 actuations demonstrations, P1.4, P1.5 separately saves the signal as the actuation chip MCS14495 locks, uses in BCD which controls produces (Binar Code Decimal), the binarycode expression tens digit is demonstrates the top digit or the lowposition.The AT89C2051 mainly completes the procedure the execution,data processing and to exterior electric circuit real-time control.Internal timer T0 work in fixed time way, when ultrasonic wave launch starts to count, after pin P3.2receives the echo,stops counting, T0 times namely for the ultrasonic wave round-trip transmission time, the monolithic integrated circuit carries on processing to this data, then determines the distance.The internal timer T1 work is counting the way, counts by P3.5pin input pulse signal control T1, counts the value by T1 to determine the automobile the rotational speed. The monolithic integrated circuit basis measured is away from and the vehicle speed carries on thecomparison, judges whether actuates the alarm circuit to report to thepolice, like hypothesis: When the vehicle speed is smaller or equal to 30km/s, the safe distance should be bigger than is equal to 1m; When the vehicle speed is smaller or equal to 80 km/s, the safe distance should be bigger than is equal to 2m; When the vehicle speed is bigger than 80 km/ s, the safe distance should bebigger than is equal to 5m .This installment control software must complete the system initialization, the control trigger pulse signal launch and the receive, according to fixed time the count-down obstacle distance, according to counts the frequency computation automobile vehicle speed, judges measured is away from whether in the margin for safety which the vehicle speed corresponds, and according to calculates has the BCD code and the corresponding frequency pulse signal with the judgement result, actuates the display circuit and the sound production electric circuit基于AT89C2051 的智能型汽车防撞报警器的设计本文介绍了AT89C2051 单片机的性能及特点，及以其为核心的一种低成本、高精度、微型化、数字显示的汽车防撞报警器。