摘 要： 超声波测距是无线测距的一种，由于其可以直接测量近距离指标，纵向分辨率高，适用范围广，方向性强，并具有不受光泽、烟雾、电磁干扰等因素影响，且覆盖面较大等所长。且在日常生活中得到广泛应用如：B超检测、雷达、倒车提醒、建筑工地距离测量等。而利用单片机的超声测距系统，硬件结构简单、工作可靠、测量误差小。95007

  本文基于51单片机的超声测距原理，策划的一种倒车防撞报警体系。此系统以超声波在空气中的传播速度为要求，利用发射声波与反射声波的时间差来计算测量距离。以单片机为控制芯片，通过单片机采样超声波信号经发射模块、反射模块后，再将信号传送给单片机处理，从而达到测距的主意。同时采用DS18B20温度补偿模块对测量环境进行温度补偿，从而提高测量数据的准确度。整个系统的设计主要包括两部分，即硬件部分和软件部分。硬件部分由超声波发射电路、超声波接收电路、电源电路、显示电路等模块组成。软件部分包括液晶显示程序、超声波发送和接收程序以及主程序。最后通过硬件和软件联调，实现了在一定距离范围内的距离测量与报警提示。此系统具有操作简单、工作可靠、测距准确度高且可达厘米级、数据读取方便等优点。

毕业论文关键词：超声波，51单片机，倒车雷达，测距，温度补偿

 Absrtact: Ultrasonic Ranging is a wireless ranging, because it can directly measure the close target, the longitudinal resolution is high, the application range is wide, the directional is strong, and has the advantages such as light, smoke, electromagnetic interference and other factors, and the coverage is big。 And in daily life has been widely used such as: B ultrasound detection, radar, reversing reminders, construction site distance measurement。   

By using the ultrasonic ranging system of MCU, the hardware structure is simple, the work is reliable and the measurement error is small。 Based on the ultrasonic ranging principle of 51 MCU, this paper designs a reversing anti-collision alarm system。 The system is based on the velocity of ultrasonic wave propagation in the air, using the time difference of transmitting acoustic wave and reflecting acoustic wave to calculate the measurement distance。 Single-chip microcomputer as the control chip, through the single-chip microcomputer sampling ultrasonic signal through the transmitter module, reflective module, and then transmit the signal to MCU processing, so as to achieve the purpose of ranging。 At the same time, Ds18b20 temperature compensation module is used to compensate the measuring environment, so as to improve the accuracy of measurement data。 The design of the whole system consists mainly of two parts, namely hardware and software。 The hardware part is composed of ultrasonic transmitting circuit, ultrasonic receiver circuit, power circuit, display circuit and so on。 The software section includes LCD display program, ultrasonic sending and receiving program, and main program。 Finally, through the hardware and software, the distance measurement and alarm prompt are realized in a certain distance range。   This system has the advantages of simple operation, reliable working, high ranging accuracy and can be up to millimeter level and data reading convenience。

 Keywords: ultrasonic, 51 MCU, reversing radar, ranging, temperature compensation

目 录

1绪论 6

1。1课题研究的背景 6

1。2课题研究的意义 6

2超声波测距系统 6

2。1超声波简介 6