基于PIC16F876A单片机的超声波测距仪

文档编号:JD763  文档字数:6950,页数:20

摘要：电子测距仪要求测量范围在0.10～5.00m，测量精度1cm，测量时与被测物体无直接接触，能够清晰稳定地显示测量结果。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，如测距仪和物位测量仪等都可以通过超声波来实现。超声波测距器，可以应用于汽车倒车、建筑施工工地以及一些工业现场的位置监控，也可用于液位、井深、管道长度的测量等场合。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，因此在移动机器人的研制上也得到了广泛的应用。
该测距仪采用NE555电路、两级放大电路和电平比较电路实现了超声波的发射与接收。单片机为该测距仪的核心单元，实现发射电路的控制和接收数据的处理。本系统在10～200cm的距离内测量精度可达±0.5cm，并且易于调试，成本低廉，具有很强的实用价值和良好的市场前景。
    关键字：超声波传感器，测距仪，PIC16F876A

Abstract：Ultrasonic Ranging, can be used in car reversing, the construction site and the location of some industrial site monitoring, can also be used if the level, depth and length of the pipeline, such as measurement occasions. Measurement of the requirements in the 0.10-5.00 m, precision 1 cm, with the measurement of detected objects without direct contact, being able to clearly show stable measurement results. Because of the strong point of ultrasonic energy consumption slow, medium of communication in the longer distance, thus frequently used ultrasonic distance measurement, such as the range finder and level measurement and so on can be achieved by ultrasound. Use of ultrasonic testing is often more rapid, convenient and simple terms, easy to achieve real-time control, and measurement accuracy can meet the practical requirements of industry, in the mobile robot has been developed on a wide range of applications.
The range finder only NE555 circuit， two amplifier circuit and the level achieved a comparison of launching and receiving ultrasound. SCM range finder for the core elements for launching the circuit control and receive data processing. 10-200 cm in the system of distance measurement accuracy up to ± 0.5cm， and easy to debug， low-cost， with strong practical value and good market prospects.
Keywords: Ultrasonic sensors, range finder, PIC16F876A

目  录

一、系统方案比较与选择 4
方案一：利用分立模块的超声波测距仪 4
方案二：基于PIC16F876A单片机的超声波测距仪 4
二、理论分析与计算 6
1、测量与控制方法 6
2、理论计算 6
三、电路与程序设计 7
1、检测与驱动电路设计 7
2、总体电路图 12
3、软件设计与工作流程图 14
四、系统调试 15
1 超声波测距误差分析 15
2 提高精度的方案及系统设计 16
3、测量结果 18
五、创新发挥 19
六、设计结论 20

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