单片机的超声测距系统设计.docVIP

摘 要 本课题详细介绍了超声波传感器的原理和特性，并在超声波测距原理的基础上，分析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单片机为核心，驱动超声波传感器的40KHz方波信号，发射电路74HC04六反相器，接收电路LM741，通过接收到信号放大和整形，最终输出负脉冲给单片机响应中断，通过LED静态扫描方式显示出来。本次测量范围20cm-2m,误差在2cm左右。 该系统电路设计合理、工作稳定、性能良好、检测速度快、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。超声波测距系统主要应用于汽车的倒车雷达、机器人自动避障行走、建筑施工工地以及一些工业现场例如：液位、井深、管道长度等场合。因此研究超声波测距系统的原理有着很大的现实意义。对本课题的研究与设计，还能进一步提高自己的电路设计水平，深入对单片机的理解和应用。 关键词：超声波，单片机，测距  ABSTRACT This subject introduces in detail the principle and characteristics of ultrasonic sensor is analyzed, and the principle of the ultrasonic ranging, based on the design of system thinking and range of problems needed to consider, given by AT89C51, drive the ultrasonic sensor signal transmission circuit, square 40KHz 74HC04 six inverter, receiving circuit receives signals LM741, through the final output amplification and plastic, the negative pulse response to interrupt, LED by MCU static scanning display. the measuring range in 20cm - 2m ,the error 2cm around. This system is stable, the circuit design is reasonable, the performance good, detection speed, simple, easy to control, and in real-time measuring precision can reach the requirement of practical industrial. Ultrasonic ranging system is mainly applied in automobile back-draft radar and automatic robot obstacle avoidance, walk, the construction site, and other industrial field such as: deep level, pipe length, etc. So the principle of ultrasonic ranging system has great realistic significance. This topic research and design, still can further improve their level of the circuit design, understanding and application of the chip. Keywords: Ultrasonic wave，One-chip computer，Range finding  目 录 摘要 Ⅰ ABSTRACT Ⅱ 第1章 绪论 1 1.1课题目的和意义 1 1.2课题主要内容 2 第2章 超声波测距系统设计 3 2.1超声波测距的原理 3 2.2超声波测距