倒车雷达测距仪

基于单片机的超声波倒车雷达设计

[摘  要]：超声波是频率高于20KHZ的声波具有指向性强，能量消耗很缓慢，在介质中传播的距离较远，因此超声波经常用于距离的测量，例如测距仪和物位测量仪等都可以通过超声波来实现。利用超声波检测往往比较迅速、高效、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。因此在液位、井深、管道长度的测量、移动机器人定位和避障等领域也得到了广泛的应用。基于此，本次设计尝试使用AT89S52与HC-SR04模块来实现超声波的测量，结合外围电路模块实现距离显示和报警构成超声波测距系统。

本次超声波测距系统由单片机计时及控制电路、超声波发射接收模块、测量距离显示电路、报警电路等部分组成。详细介绍了超声波测距模块及AT89S52单片机的测距原理。以HC-SR04超声波测距模块为核心实现超声波的发射与接收。显示电路采用数码管以及三极管显示控制，报警电路由蜂鸣器与三极管组成。整体电路结构简单，成本低廉，工作稳定，测量精度也达到实际应用要求。

[关键词]: AT89C52，HC-SR04，超声波，测距

目录

摘要······························································1

1  绪论 ··························································2

1.1   项目研究背景及意义·······································2

1.2    文档结构················································2

2  总体设计方案及论证 ·············································2

2.1   总体方案设计 ············································2

3  硬件实现及单元电路设计 ········································3

3.1  主控制模块 ···············································3

3.2  电源设计 ·················································4

3.3  超声波测试模块 ···········································4

3.3.1  超声波的特性 ·······································5

3.3.2  超声波换能器 ·······································6

3.4  超声波传感器原理 ·········································8

3.5  测距分析 ···············································12

3．6 单片机AT89C52····················································13

3.7  声音报警电路的设计 ······································14

3.8  显示模块 ················································14

4  软件设计 ·····················································15

4.1  主程序工作流程图 ········································15

5  总结 ·························································17

6  参考文献 ·····················································17

附 录 ···························································18

附件A：实物作品操作 ·········································18

    附件1：原理图 ···············································21

    附件2：程序 ·················································22

    附件3：元件清单 ·············································29