摘 要
广州汽车展现在各大中城市出租车行业都已普及自动计价器，所以计价器技术的发展已成定局，预计未来计价器市场很有前景。计价器作为出租车的一个重要组成部分，关系着出租车司机和乘客双方利益，起着重要的作用，因此，具有良好性能的计价器对广大出租车司机朋友和乘客来说是很必要的。但是现阶段出租车的计费系统功能有时候并不能满足出租车司机的意愿。
本课题是出租车计价器系统的设计。重点是设计出租车计价器的实用性，并尽量使最后的成品接近于商品。整个系统是以89S51单片机为中心，采用A44E霍尔传感器对轮胎转数进行计数，实现对出租车里程的测量，并最终计算出结果。其中采用掉电存储芯片AT24C02使系统在掉电的时候对单价、里程等信息进行存储，人机交换界面采用的是LCD1602液晶屏显示，并且通过语音芯片进行播报。本电路设计的出租车计价器不但能实现计价的功能，同时还能实现根据时钟芯片自动调整白天、黑天计价模式，能自动处理中途等待等功能。
关键词：单片机AT89S51；LCD1602；出租车计价器；霍尔传感器；AT24C02

ABSTRACT
Automatic taximeter has been universal among Cities for now. The taximeter technology is a foregone conclusion already. So taximeter of cars is still potential at next generation. As an important component taximeter is not only the interests of taxi drivers but also the passengers, so it has played an important role. The good performed taximeter is necessary for the public. The current taxi billing systems don’t meet the wishes of people. In this article we talk about various designs of taximeter system.   
The point is to design the practicality of the taximeter and as far as possible to make the final finished product close to commodities. The whole system is based on single-chip 89S51 and use a hall-sensor A44E to count the number of revolutions. In this way we can achieve the statistics of the taxi mileage and give out the final results. In this design we use AT24C02 to store the price, mileage and other information when the power is down. The man-machine interface of the exchange is LCD1602 screen, and through the voice chip broadcasts. This circuit design can not only realize the meter taxi valuation function, but also can realize the automatic adjustment according to the clock chips during the day, dark pricing mode, it can automatic processing midway waiting for function.
Keywords: single-chip AT89S51; LCD1602; Taximeter; Hall sensor; AT24C02