[优秀毕业设计精品]基于单片机微型数显超声波测距仪系统设计

毕业设计（论文）题目超声波测距仪专业机电一体化班级学号姓名指导老师XXXA1A2A2A3A0A4A5XXXA6A7A8A9A10A11A12A131摘要超声波具有指向性强，能量消耗缓慢，传播距离较远等优点，所以，在利用传感器技术和自动控制技术相结合的测距方案中，超声波测距是目前应用最普遍的一种，它广泛应用于防盗、倒车雷达、水位测量、建筑施工工地以及一些工业现场。本课题详细介绍了超声波传感器的原理和特性，以及ATMEL公司的AT89C51单片机的性能和特点，并在分析了超声波测距的原理的基础上，指出了设计测距系统的思路和所需考虑的问题，给出了以AT89C51单片机为G7692G5527的G1314G6116本、G20652G12946G5242、G5506G3423G2282G6980G4395G7186G12046超声波测距G1214的G11840G1226G11017路和G17731G1226设计方G8873。G16825系统G11017路设计合理、工G1328G12295G4462、性能G14403G3921、G7828测G17907G5242G5567、计G12651G12628单、G7143于G1582G2052G4466G7114控制，并G1000在测量G12946G5242方G19766能达G2052工业G4466用的G16213G8726。关键词A14A15A16A17A18A19A20A21AT89C51XXXA6A7A8A9A10A11A12A132ABSTRACTG56LTG85G68G86G82G81G76G70G90G68G89EG75G68G86G86TG85G82G81G74G83G82G76G81TG76G81G74TG82G81G68TG88G85EG15G86LG82G90LG92EG81EG85G74G92G70G82G81G86G88MG83TG76G82G81G15G83G85G82G83G68G74G68TG76G81G74G71G76G86TG68G81G70EG73G68G85TG75EG85G15G86G82G15G76G81G88TG76LG76G93G76G81G74TG75EG86G70G75EMEG82G73G71G76G86TG68G81G70EG73G76G81G71G76G81G74TG75G68TG86EG81G86G82G85TEG70G75G81G82LG82G74G92G68G81G71G68G88TG82MG68TG76G70G70G82G81TG85G82LTEG70G75G81G82LG82G74G92G70G82MG69G76G81ETG82G74ETG75EG85G15G88LTG85G68G86G82G81G76G70G90G68G89EG73G76G81G71G86G85G68G81G74ETG82G88G86ETG75EMG82G86TG74EG81EG85G68LG82G81EG68TG83G85EG86EG81TG15G76TG68G83G83LG76EG86TG82G74G88G68G85G71G68G74G68G76G81G86TTG75EG73TG15MG82G89EG69G68G70G78G90G68G85G71TG75EG85G68G71G68G85G15G90G68TEG85LEG89ELMEG68G86G88G85G76G81G74G15G69G88G76LG71G76G81G74G70G82G81G86TG85G88G70TG76G82G81G86G76TEG68G81G71G86G82MEG76G81G71G88G86TG85G76G68LG86G70EG81EG86EG91TEG81G86G76G89ELG92。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。KEYWORDSG56LTG85G68G86G82G81G76G70G90G68G89EG30G50G81EG16G70G75G76G83G70G82MG83G88TEG85G30G53G68G81G74EG73G76G81G71G76G81G74G30AT89C51XXXA6A7A8A9A10A11A12A133目录A22A231A24A25A26A27A28A24A29A272A30A313A321A33A34A35A36A37A38A39A40A41A42A34A35A36A37A38A39A40511A43A44A45A46A47A48A49A50512A43A44A45A46A47A51A52A53A54A48A55A565121A57A58A59A60A61A625122A63A64A65A66A67A59A606123A68A69A65A66A67A59A607124A70A71A72A73A67A59A60813A74A75A76A77A78A79A80A81A82A83A84A85914A86A87A88A8911A902A91A92A931221A94A95A96A97A98A99A100A101A102A1031222A104A105A106A107A100A108A109A110A111A112A113A11412221A115A116A117A118A119A120A121A122A123A124A125A126A12712222A115A116CPLDA120A121A122A123A124A125A126A1271323A128A129A130A131A132A13314A1343A135A136A137A138A139A140A141A139A140A1411531A142A143A144A145A146A147A148A149A150A151A152A15315311A154A15515312A156A1571632A158A159A160A161A162A163A164A165A166A167A1681733A158A159A160A161A162A163A169A170A164A171A1721834A173A174A175A17619A1774A178AT89C51A179A180A181A182A1832041A184A185A186A187A188A189A19020411A191A192A193A194A195A196A197A19820412A191A192A193A194A199A200A201A202A203A2042242A205A206A207A208A209A210A211A212A2132343A205A206A207AT89C51A208A214A2152444A216A217A218A21927A2205A221A222A223A224A225A226A227A228A229A230A225A226A227A228A229A2302851A231A232A233A234A2352852A236A237A233A238A239A240A24128521A242A243A244A245A246A247A24828522A249A250A251A252A253A254A255A20A246A0A12954A17A2A3A430XXXA5A6A7A8A9A10A11A124A42A1331A43A1432A45A15A16A18A45A15A16A1833A49A19134A49A19239A49A19340XXXA21A22A23A24A25A26A27A285第1章超声波测距系统设计11超声波测距的原理单片机G2469出超声波测距是G17902G17819G993G7041G7828测超声波G2469G4568G2530G17947G2052G19568G11873G10301所G2465G4568的G3250波G15G1186G13792测出G2469G4568和G6521G6922G3250波的G7114G19400G5058T，G9994G2530G8726出距离2CTSA29A30A31A30A32G5347G111G161G12中的C为超声波在G12366G8680中传播的G17907G5242。G19492制G16825系统的最G3835G2499测距离G4396在G3247G1022G3252G13044G726超声波的G5145G5242、G2465G4568G10301的G17148地、G2465G4568和G1849G4568声波G1055G19400的G3853G16294以及G6521G6922G6454能器的G9801G6947G5242。G6521G6922G6454能器G4557声波G14045G1926的G11464G6521G6521G6922能G2159G4570G1927G4462最G4579G2499测距离。为了G3698G2164所测量的G16218G11434G14551G3272，G1955少测量误G5058，G2499采用多G1022超声波G6454能器分别G1328为多路超声波G2469G4568/G6521G6922的设计方G8873。由于超声波G2469球声波G14551G3272，其波G17907C与温G5242有关，表1G161列出了几种G993同温G5242下的波G17907。A33A30A31A30A34A35A36A37A38A39A40A41A37A38A29A44A32A46A47A48A46A50A48A46A30A48A48A30A48A50A48A47A48A30A48A48A34A35A29A51A52A53A32A47A30A47A47A30A54A47A50A55A47A50A47A47A47A56A47A57A57A47A57A54A47A56A58波G17907确G4462G2530，只G16213测得超声波往返的G7114G19400T，即G2499G8726得距离S。其系统原理框图如图1G161所G12046。A59A30A31A30A60A34A61A62A63A41A64A65A59单片机AT89C51G2469出短暂的40G78HG93信号，经放G3835G2530G17902G17819超声波G6454能器输出；G2465G4568G2530的超声波经超声波G6454能器G1328为系统的输G1849，锁相环G4557此信号锁G4462，产生锁G4462信号启动单片机中G7041程序，读出G7114G19400T，再由系统G17731G1226G4557其进行计G12651、判别G2530，相应的计G12651结果被送至LEDG6980码管进行G7186G12046。在下一节里，我们G4570详细介绍超声波测距G1214的各部分G11017路的设计思路及方G8873。12超声波测距系统电路的设计121总体设计方案由单片机AT89C51编程产生40G78HG93的方波，由P36口输出，再经G17819放G3835G11017XXXA66A67A68A69A70A71A72A736路，驱动超声波G2469G4568探头G2469G4568超声波。G2469G4568出去的超声波经G19568G11873G10301G2465G4568G3250来G2530，由超声波G6521G6922头G6521G6922G2052信号，G17902G17819G6521G6922G11017路的G7828波放G3835、积分整形及一系列处理G15送至单片机。单片机利用声波的传播G17907G5242和G2469G4568G14045G1926G2052G6521G6922G2465G4568G14045G1926的G7114G19400G19400隔计G12651出G19568G11873G10301的距离G15并由单片机控制G7186G12046出来。G16825测距装置是由超声波传感器、单片机、G2469G4568/G6521G6922G11017路和LEDG7186G12046器组G6116。传感器输G1849端与G2469G4568G6521G6922G11017路相连G15G6521G6922G11017路输出端与单片机相连G6521G15单片机的输出端与G7186G12046G11017路输G1849端相连G6521。其G7114序图如图1G162所G12046A74A75A76A77A78A79A80A75单片机在TA81G7114刻G2469G4568方波，同G7114启动G4462G7114器开始计G7114，当G6922G2052G3250波G2530，产生一负跳变G2052单片机中G7041口，单片机响应中G7041程序，G4462G7114器停止计G6980。计G12651G7114G19400G5058，即G2499得G2052超声波在媒介中传播的G7114G19400T，由此便G2499计G12651出距离。122发射电路的设计由单片机产生的40G78HG93的方波需G16213进行放G3835，才能驱动超声波传感器G2469G4568超声波，G2469G4568驱动G11017路其G4466就是一G1022信号放G3835G11017路，本课题所选用的是74HC04集G6116芯片，图1G163为G2469G4568G11017路图。XXXA66A67A68A69A70A71A72A737A75A76A77A82A83A84A85A8674HC04内部集G6116了六G1022G2465向器，同G7114具有放G3835的功能。74HC04的管脚如图1G164所G12046。A75A76A77A87A88A87A89A90A91A87A92A93A75123接收电路的设计超声波G6521G6922头G6521G6922G2052超声波G2530，转G6454为G11017信号，此G7114的信号比较弱，必需经G17819放G3835。本系统采用了LM741G4557G6521G6922G2052的信号进行放G3835，G6521G6922G11017路如图1G165所G12046。XXXA66A67A68A69A70A71A72A738A75A76A77A94A95A96A85A86超声波探头G6521G6922G2052超声波G2530，G17902G17819声G11017转G6454，产生一正弦信号，其频率为传感器的中G5527频率，即40G78HG93。G16825信号G17902G17819C1G20652G17902滤波G2530经LM741放G3835，最G2530经二极管整形G2530输出G2052单片机中G7041口。LM741是一单运放集G6116芯片，图1G166为LM741管脚图。A75A76A77A97A98A99A100A101A102A103A104A105124显示模块的设计LEDG11LG76G74G75TG16EMG76TTG76G81G74DG76G82G71E，G2469光二极管G12有七段和八段G1055分，G1075有G1861G19464和G1861G19463G1016种。LEDG6980码管结G7512G12628单，G1227G7696便G4464。图1G167G12046出了八段LEDG6980码G7186G12046管的结G7512和原理图。图1G167G11G68G12为八段G1861G19464G6980码G7186G12046管结G7512图，图1G167G11G69G12是它的原理图，图1G167G11G70G12为八段G1861G19463LEDG7186G12046管原理图。八段LEDG7186G12046管由八只G2469光二极管组G6116，编号是G68、G69、G70、G71、E、G73、G74和SP，分别与同G2529管脚相连。七段LEDG7186G12046管比八段LED少一只G2469光二极管SP，其G1194与八段相同。XXXA106A107A108A109A110A111A112A1139A105A102A114A100A115A116A98A117A118A119A120A121A122A103A123A124A125A126A127单片机G4557LED管的G7186G12046G2499以分为G19757G5589和动G5589G1016种。G19757G5589G7186G12046的特点是各LED管能G12295G4462地同G7114G7186G12046各自G4395形；动G5589G7186G12046是指各LEDG17730G8981地一遍一遍G7186G12046各自G4395G12538，G1166们由于G16282G16285器G4460G5828性，G1186G13792G11487G2052的是各LEDG1296G1058在同G7114G7186G12046G993同G4395形。为了G1955少G11840G1226开G19156，G6564G20652系统G2499G19764性并G19489G1314G6116本，单片机控制系统G17902G5132采用动G5589G6207G6563G7186G12046。G1306是由于本系统所用的单片机G5353脚少，G2109G1325G5353脚G5468多，G13792G1000G1075只需G7186G12046G989位G4395G12538，所以，采用了G19757G5589的G7186G12046方G5347，G1000采用了G17731G1226G16805码，G17837G7691单片机G5353脚输出G2499G11464G6521G6521G2052LEDG7186G12046管上。G17837G7691G11477去了G3818部G3809G7446的G16805码G11017路。13超声波测距系统的软件设计单片机编程产生超声波，在系统G2469G4568超声波的同G7114利用G4462G7114器的计G6980功能开始计G7114，G6521G6922G2052G3250波G2530，G6521G6922G11017路输出端产生的负跳变在单片机的G3818部中G7041G9316输G1849口产生一G1022中G7041G16843G8726信号，响应G3818部中G7041G16843G8726，G6203行G3818部中G7041G7393G2165G4388程序，停止计G7114，读G2474G7114G19400G5058，计G12651距离，G9994G2530G17902G17819G17731G1226G16805码，G4570G6980G6466输出P0、P1和P2口G7186G12046。程序G8981程图如图1G168，G11G68G12为G1039程序G8981程图，G11G69G12为G4462G7114中G7041G4388程序G8981程图，G11G70G12为G3818部中G7041G4388程序G8981程图。A128A129A130A128A131A130A128A132A130A133A134A135A136A137A138A139A137A133XXXA140A141A142A143A144A145A146A14710用单片机编程产生40G78HG93方波，G2499用G5322G7114程序和G5502环G16833G2489G4466现。G1820G4462G1053一G1022G5322G7114G2001G6980G71ELG68G92G86G11G12，G9994G2530G2499用G73G82G85G16833G2489G5502环，并G1000G5502环一G8437同G7114G6925变方波输出口的G11017G5191G20652G1314，G1186G13792产生方波。部分程序如下G726G89G82G76G71G71ELG68G92G86G11G12G94G96/G5322G7114G2001G6980G89G82G76G71MG68G76G81G11G12G94G73G82G85G11G68G320G30G68G31200G30G68G14G14G12/产生100G102240G46HG93的方波G94P36G32G4P36G30/G8611G5502环一G8437，输出G5353脚G2474G2465G71ELG68G92G86G11G12G30G96G96单片机G8611隔一段G7114G19400产生一G103040G78HG93方波，同G7114G4462G7114器开始计G7114，当G6922G2052G3250波，产生中G7041信号G2530，单片机G6203行中G7041程序。在中G7041程序中，G1820G16765G4462G7114器停止计G6980，G9994G2530读G2474G7114G19400，G17902G17819G7114G19400计G12651出所测距离，输出结果。中G7041程序如下G726G89G82G76G71G76G81TEG85G86G89G85G82G11G89G82G76G71G12G76G81TEG85G85G88G83T0G88G86G76G81G741/G44G49TG50中G7041G7393G2165程序G94G88G76G81TG69G90EG76G15G86G75G90EG76G15G74G90EG76G30G88G70G75G68G85DHG15DLG30G88LG82G81G74CG50G56G49TG30G88LG82G81G74G81G88MG30TG530G320G30/停止计G6980DHG32TH0G30DLG32TL0G30CG50G56G49TG32TH0G13256G14TL0G30G81G88MG32G11344G13CG50G56G49TG12/20000G30/计G12651距离G69G90EG76G32G81G88M/100G30/G2474G11346位G74G90EG76G32G11G81G88MG16G69G90EG76G13100G12/10G30/G2474G2325位G86G75G90EG76G32G81G88MG810G30/G2474G1022位P1G32TG68G69G62G69G90EG76G64G30/输出G11346位P0G32TG68G69G62G86G75G90EG76G64G30/输出G2325位P2G32TG68G69G62G74G90EG76G64G30/输出G1022位TH0G320G30XXXA140A141A142A143A144A145A146A14711TL0G320G30G96本系统的LEDG7186G12046采用了G19757G5589G7186G12046方G5347，并用单片机内部G17731G1226G16805码。G17837G7691G12628单方便，G11477去了G3809G7446的G3818部G16805码G11017路。G17731G1226G16805码只需G16213G4462G1053一G1022G6980组便G2499，程序G16833G2489如下G726G88G70G75G68G85G71G68TG68TG68G69G6210G64G32G940G91G700G150G91G739G150G91G684G150G91G690G150G9199G150G9192G150G9182G150G91G738G150G9180G150G9190G96G30G17837是G1861G19463LEDG7186G12046G11860G20529的G4395形码。14本章小结本G12468是G16825课题的G18337点，G1852G19766介绍了超声波测距系统的原理和设计思路，给出了G11840G1226G11017路和G17731G1226的设计。在G11840G1226G11017路的设计中，分别详细介绍了G2469G4568G11017路，G6521G6922G11017路及G7186G12046G8181G3371的设计方G8873。G17731G1226编程部分，给出了整G1022程序的思路以及程序G8981程图。XXXA140A141A142A143A144A145A146A14712第2章绪论21课题背景，目的和意义传感器技术是现G1207信G5699技术的G1039G16213内G4493G1055一。信G5699技术G2265G6336计G12651机技术、G17902信技术和传感器技术，计G12651机技术相当于G1166的G3835G14053，G17902信相当于G1166的G12082经，G13792传感器就相当于G1166的感G4460。比如温G5242传感器、光G11017传感器、G9299G5242传感器、超声波传感器、G13430G3818传感器、G2399G2159传感器等等，其中，超声波传感器在测量方G19766有G11540广泛、普遍的应用。利用单片机控制超声波G7828测往往比较G17817G17907、方便、计G12651G12628单、G7143于G1582G2052G4466G7114控制，并G1000测量G12946G5242较G20652。超声波测距系统G1039G16213应用于G8785车的倒车雷达、机器G1166自动G18003G19568行G17220、建筑施工工地以及一些工业现场G1375如G726G9094位、G1129G9157、管G17959G19283G5242等场合。G3252此G11752G12362超声波测距系统的原理有G11540G5468G3835的现G4466G5859G1053。G4557本课题的G11752G12362与设计，G17836能进一G8505G6564G20652自G5061的G11017路设计水G5191，G9157G1849G4557单片机的理G16311和应用。22两种常用的超声波测距方案221基于单片机的超声波测距系统基于单片机的超声波测距系统，是利用单片机编程产生频率为40G78HG93的方波，经G17819G2469G4568驱动G11017路放G3835，G1363超声波传感器G2469G4568端G19675G14645，G2469G4568超声波。超声波波经G2465G4568G10301G2465G4568G3250来G2530，由传感器G6521G6922端G6521G6922，再经G6521G6922G11017路放G3835、整形，控制单片机中G7041口。其系统框图如图2G161所G12046。A148A149A150A151A152A153A154A155A156A157A158A159A160A161A162A163A164A165A148G17837种以单片机为G7692G5527的超声波测距系统G17902G17819单片机G16772G5417超声波G2469G4568的G7114G19400和G6922G2052G2465G4568波的G7114G19400。当G6922G2052超声波的G2465G4568波G7114，G6521G6922G11017路输出端产生一G1022负跳变，在单片机的G3818部中G7041G9316输G1849口产生一G1022中G7041G16843G8726信号，单片机响应G3818部中G7041G16843G8726，G6203行G3818部中G7041G7393G2165G4388程序，读G2474G7114G19400G5058，计G12651距离，结果输出给LEDG7186G12046A166A167A168。利用单片机G1946确计G7114，测距G12946G5242G20652，G13792G1000单片机控制方便，计G12651G12628单。G16780多超声波测距系统G18129采用G17837种设计方G8873。XXXA169A170A171A172A173A174A175A17613222基于CPLD的超声波测距系统G17837种测距系统采用CPLDG11CG82MG83LEG91PG85G82G74G85G68MMG68G69LELG82G74G76G70DEG89G76G70EG12器G1226，运用G57HDLG11G57EG85G92HG76G74G75SG83EEG71G44G81TEG74G85G68TEG71CG76G85G70G88G76THG68G85G71G90G68G85EDEG86G70G85G76G83TG76G82G81LG68G81G74G88G68G74EG12编G1901程序，G1363用MAG59G14G83LG88G86G44G44G17731G1226进行G17731G11840G1226设计的G1235G11507和调试，最终G4466现测距功能。CPLD器G1226内部的宏单元是其最基本的G8181G3371，能独立地编程为D触G2469器、T触G2469器、G53S触G2469器或JG46触G2469器工G1328方G5347或组合逻辑工G1328方G5347。它的G17837种特性非G5132适用于本系统，G2499G4570本系统所需G16213的分频功能、计G6980功能、振G14645器、七段码G7186G12046G1852部由MAG59来G4466现，G13792只需在G3818部配上适当的超声波传感器、G6521G6922和G2469送G11017路，即G2499组G6116一G1022测量G12946G5242G20652、性能G12295G4462、响应G17907G5242G5567G1000具有G7186G12046功能的超声波测距G1214。本系统利用CPLD器G1226控制超声波的G2469G4568，并G4557超声波G2469G4568至G6521G6922的往返G7114G19400进行计G6980，G4570计G12651结果在LED上G7186G12046出来。配合G1363用MAG59G14G83LG88G86G44G44开G2469G17731G1226，G2499集设计输G1849、设计处理、设计校验和器G1226编程于一体，集G6116G5242G20652，开G2469周期短。其系统框图如图2G162所G12046。A177A178A179A178A180A181A182A183A184A185A186A187A188A189A190A191A192A193A194A177超声波G2469G4568器向某一方向G2469G456840G78HG93的超声波，在G2469G4568超声波的同G7114，MAG597128S内的计G6980器开始计G6980。超声波在G12366G8680中传播，途中碰G2052G19568G11873G10301就会立即返G3250来。超声波G6521G6922器G6922G2052G2465G4568波G2530就G4570G3250波信号送G2052CPLD，CPLD立即停止计G6980。CPLD所计的G7114G19400就是超声波G1186传感器G2052被测G10301的往返G7114G19400。超声波在G12366G8680中的传播G17907G5242如设G4462为332M/G86，根G6466计G6980器G16772G5417的G7114G19400T，就G2499以计G12651出G2469G4568点距G19568G11873G10301的距离S，即G726G86G32332T/2。CPLD开始计G6980G2530，只G16213传感器G6922G2052G3250波，CPLD就立即停止计G6980，即只有最G1820返G3250的超声波才起G1328用，G1075就是说超声波测距G1214总是测得离传感器最近的G10301体的距离A195A196A197。本系统采用G1820进的CPLD器G1226，G20652性能、G1314G6116本地G4466现了距离的测G4462。XXXA198A199A200A201A202A203A204A2051423课题主要内容G17902G17819上节介绍我们知G17959，以单片机为G7692G5527的超声波测距系统设计G12628单、方便，G13792G1000测G12946G5242能达G2052工业G16213G8726。本课题G11752G12362的测距系统就是用单片机控制的。G17902G17819超声波G2469G4568器向某一方向G2469G4568超声波，单片机在G2469G4568G7114刻同G7114开始计G7114，超声波在G12366G8680中传播，途中碰G2052G19568G11873G10301就立即G2465G4568G3250来，超声波G6521G6922器G6922G2052G2465G4568波就立即停止计G7114。超声波在G12366G8680中的传播G17907G5242为V，根G6466计G7114器G16772G5417的G7114G19400T，就G2499以计G12651出G2469G4568点距G19568G11873G10301的距离。本系统利用单片机控制超声波的G2469G4568和G4557超声波自G2469G4568至G6521G6922往返G7114G19400的计G7114。G6521G6922G11017路的输出端G6521单片机的G3818部中G7041G9316输G1849口。系统G4462G7114G2469G4568超声波，在启动G2469G4568G11017路的同G7114启动单片机内部的G4462G7114器，利用G4462G7114器的计G6980功能G16772G5417超声波G2469G4568的G7114G19400和G6922G2052G2465G4568波的G7114G19400。当G6922G2052超声波的G2465G4568波G7114，G6521G6922G11017路输出端产生一G1022负跳变，在单片机的G3818部中G7041G9316输G1849口产生一G1022中G7041G16843G8726信号，单片机响应G3818部中G7041G16843G8726G6203行G3818部中G7041G7393G2165G4388程序，读G2474G7114G19400G5058，计G12651距离G15结果输出给LEDG7186G12046。利用本测距系统测量，G14551G3272应在30G70M200G70M内，其最G3835误G5058控制在10G70M。XXXA198A199A200A201A202A203A204A20515第3章超声波传感器为了G11752G12362和利用超声波，G1166们已经设计和制G6116了G16780多超声波G2469生器。总体上讲，超声波G2469生器G2499以分为G1016G3835类G726一类是用G11017G8680方G5347产生超声波，一类是用机械方G5347产生超声波。G11017G8680方G5347G2265G6336G2399G11017G3423、磁致伸缩G3423和G11017动G3423等；机械方G5347有G2164尔统笛、G9094哨和G8680G8981旋笛等。它们所产生的超声波的频率、功率和声波特性各G993相同，G3252G13792用途G1075各G993相同。目前较为G5132用的是G2399G11017G5347超声波G2469生器。G2399G11017G5347超声波G2469生器G4466际上是利用G2399G11017晶体的谐振来工G1328的。它有G1016G1022G2399G11017晶片和一G1022G1861振板。当它的G1016极G3818G2164G14045G1926信号，其频率等于G2399G11017晶片的G3252有振G14645频率G7114，G2399G11017晶片G4570会G2469生G1861振，并带动G1861振板振动，便产生超声波。G2465G1055，如果G1016极G19400未G3818G2164G11017G2399，当G1861振板G6521G6922G2052超声波G7114，G4570G2399迫G2399G11017晶片振动，G4570机械能转G6454为G11017信号，G17837G7114它就G6116为超声波G6521G6922器了。在设计超声波测距系统G1055前，我们首G1820来了G16311一下有关超声波传感器方G19766的知识。在本G12468里，G4570介绍超声波传感器的原理和特性，G7828测方G5347以及超声波传感系统的G7512G6116。31超声波传感器的原理与特性311原理G1166们G2499以听G2052的声音频率为20HG9320G78HG93，即为G2499听声波，超出此频率G14551G3272的声音，即20HG93以下的声音称为G1314频声波，20G78HG93以上的声音称为超声波，一般说话的频率G14551G3272为100HG938G78HG93。超声波为G11464线传播方G5347，频率越G20652，绕G4568能G2159越弱，G1306G2465G4568能G2159越强，为此利用超声波的G17837种性G17148就G2499以制G6116超声波传感器。另G3818，超声波在G12366G8680中传播的G17907G5242较慢，约为330M/G86，G17837就G1363得超声波传感器G1363用变得非G5132G12628单。超声波传感器有G2469送器和G6521G6922器，G1306一G1022超声波传感器G1075G2499以具有G2469送和G6521G6922声波的双G18337G1328用，即为G2499逆元G1226。一般市场上出售的超声波传感器有专用G3423和兼用G3423，专用G3423就是G2469送器用G1328G2469送超声波，G6521G6922器用G1328G6521G6922超声波；兼用G3423就是G2469送器和G6521G6922器为一体传感器，即G2499G2469送超声波，又G2499G6521G6922超声波。超声波传感器的谐振频率G11中G5527频率G12有23G78HG93、40G78HG93、75G78HG93、200G78HG93、400G78HG93等。谐振频率变G20652，则G7828测距离变短，分G16311G2159G1075变G20652。超声波传感器是利用G2399G11017效应的原理，G2399G11017效应有逆效应和顺效应，超声波传感器是G2499逆元G1226，超声波G2469送器就是利用G2399G11017逆效应的原理。所谓G2399G11017逆效应如图3G161所