说明：  本电路以89S51 单片机为中心、附加A44E 霍尔传感器测距，实现对出租车计价统计，采用AT24C02 实现在系统掉电的时候保存单价和系统时间等信息，输出采用8 段数码显示管。本电路设计的计价器不但能实现基本的计价，而且还能根据白天、黑夜、中途等待来调节单价，同时在不计价的时候还能作为时钟为司机同志提供方便。
(The single-chip circuitry to 89S51 as the center, an additional Hall sensor A44E ranging, to realize Taximeter statistics, using AT24C02 realize when the system power-down unit prices and save information such as system time, the output using 8 digital display tube. The circuit design of the meter will not only realize the basic valuation, but also according to the daytime, night, halfway to wait to adjust the unit price, while not denominated as a time clock can also provide convenience for the drivers comrades.)