摘
要
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。其中由于泊车事故发生的频率高，已引起了社会和 交通部门的高度重视。泊车事故发生的原因是多方面的，造成泊车时的事故率远大于 汽车正常行驶时的事故率，尤其是非职业驾驶员以及女性更为突出。而泊车事故给车 主带来许多麻烦，不仅经济上，更有人身伤害，例如撞上别人的车，如果伤及儿童更 是不堪设想，基于此基础，汽车高科技产品中，专为汽车泊位设置的“汽车泊车辅助 系统”应运而生，汽车泊车辅助系统的加装可以解决司机的不少麻烦，大大降低了泊 车事故的频率。 由于超声波指向性强，能量消耗缓慢，在介质中传播的距离较远，因而超声波经 常用于距离的测量。利用超声波检测往往比较迅速、方便、计算简单、易于做到实时 控制，并且在测量精度方面能达到工业实用的要求。本系统工作过程中超声波发射器 发出一系列的脉冲信号，由单片机对接收的信号依据时间差进行处理，自动计算出车 与障碍物之间的距离。超声波测距原理简单，成本低，制作方便，但其传输速度受天 气影响较大，不能精确测距；因此大都用于汽车倒车雷达等近距离测距中本文根据声 波在空气中传播反射原理，以超声波换能器为接口部件 该设计由超声波发射模块、信号接收模块、单片机处理模块、数码显示以及声光 报警显示模块等部分组成，文中详细介绍了测距器的硬件组成、检测原理、方法以及 软件结构。 接收电路使用 NE5532 及 LM311 芯片对回波信号进行整波， 对衰减后的信号 进行了放大和整波，更好的实现了超声波的接受，对单片机提供外部中断信号。
关键词：超声波；报警；AT89S52；设计；调试
evelopment of our economy, transportation vehicles and private cars, inevitably increase traffic problems instantaneous become people concern. The accident happened because of high frequency meter has attracted social and communications departments are highly valued. Parking the cause of the accident is various, the accidents caused by parking when normally running far outweigh its car accident rates, especially the female driver and nonprofessional is more prominent. And parking accident brings a lot of trouble for owners, not only economically, more personal injury, such as hitting someone else's car, if injury and children is unimaginable, based on this foundation, car high-tech product, designed for car parking garages Settings "car auxiliary system" appeared, car parking auxiliary system can solve the driver with a lot of trouble, and greatly reduce the frequency of parking accident. Due to the strong ultrasonic directivity slowly, and energy consumption in a medium transmission distance is farther, thus ultrasonic often used for distance measurement. Using ultrasonic detection tend to be quick, convenient, simple calculation, easy to achieve real-time control, and the precision in the measurement of industrial practical requirement can achieve. This system work process issued a series of ultrasonic pulse signal transmitter, by SCM according to receive the signal processing, automatic calculation lag between the distance between the car and the obstacles. Ultrasonic ranging principle, low cost, simple production convenient, but its transmission speed greatly influenced by the weather, not accurate location; So mostly used in automobile reverse radar etc close ranging according to airborne sound in ultrasonic transducer, reflected in the principle for interface components This design by ultrasound module, the signal receiving module and single-chip microcomputer processing module, digital display and the acousto-optic alarm display module components, this paper introduces in detail the range finder hardware composition, measuring principle, method and software structure. Receiving circuit NE5532 and LM311 chips used to echo signal of the wave, the attenuation of signal amplifier and the whole wave, better realize the ultrasound accepted, the SCM provide external interrupt signal. Keywords: ultrasonic; Alarm; AT89S52 devices; Design; debugging