摘要近年来，我国经济发展的势头十分迅猛。在其影响下，交通运输行业也变得越来越重要。铁路作为交通运输的主力军，自然而然地获得了极其巨大的发展。列车是铁路运输的重要元素，火车时速已经从过去的不到百公里提速到五百公里。无疑列车的时速是现代铁路运输发展的重要标志之一。伴随列车大跨度的提速而来是安全运输的问题。我们既要保证高效率的铁路运输，也要保证运输的安全。69867

在铁路安全运输的环节中，有一个一直存在的巨大的薄弱点：平交道口。自从铁路发明以来，每一代人都为解决铁道平交道口安全做出了不可磨灭的贡献。本设计也是来解决这个问题的。通过深入地了解和分析当前我国的平交道口的实际情况，将设计出一套完整的基于单片机的平交道口自动系统报警系统。在距离道口约两公里的地方安放传感器,这里的传感器能使道口获知临近列车的具体情况，如列车通过传感器的时速、列车到达道口的预估时间。置放在道口的单片机处理由传感器送达的信息，然后促使道口报警设备作出相应的反应。本设计中最为重要的部分就是单片机处理电路。在这里我们选用单片机AT89C51芯片。它的很多优越的性能决定了选它担任这个重担。比如说它的可靠性极高，它的价位极低，更重要的是基层技术人员非常容易掌握和学习这个芯片。这样，技术人员能在短时间内解决一些基本故障。由于铁路道口的工作环境不是太理想，有些道口环境甚至非常恶劣。这些糟糕的工作环境在一定程度上对系统造成干扰。在这里，我们就针对各种干扰，我们从软件和硬件方面设计出相对应的抗干扰措施。在可视度极低的天气情况下，（譬如说雨雾天气）本设计可以为道口值班人员提供具体的准确的列车信息，帮助值班人员指挥道口交通。  本设计有图24幅，表7个，参考文献33篇

毕业论文关键词 : 单片机  传感器  自动报警。

Microcontroller-based railway crossing automatic alarm system design

Abstract In recent years, China's economic development is very rapid. Under its influence, the transport sector has become increasingly important.As the main force of Railway Transport,Railway naturally get extremely huge development .Speed of train have improved from one hundred kilometers before to five hundred kilometers now.Undoubtedly ,speed of train is an important symbol of modern railway transport development.With the large span speed , the safe transport problems should be noticed.We need to ensure efficient of rail transport, but also to ensure safe transport.During the links of railway transport security, there is a huge weak point which has always been there,this point is level crossing.Since the railroad is invented, each generation has made an indelible contribution in solving the railway level crossing safety .The aim of this design is to solve this problem .Through in-depth understanding and analysis of the current situation of our country level crossing,It is expected that we need design automatic alarm level crossing system based on a single-chip.There is sensor which is placed in about two kilometers from level crossing.Here sensors enable level crossing learn about the specific circumstances of the train which is near.As the speed of the train , the estimated time of train crossing. single-chip placed in the level crossing deal with information processed by the sensor .Then crossing alarm device is prompted to respond to accordingly.The single-chip processing circuit is the most important part of the design .Here we use chip micro-controller AT89C51.Many of its superior performance determines that it can be chose to take this burden.For example, its high reliability, its low price , more importantly, grassroots art can learn and master this chip easily.since the railway crossing working environment is not too good, and some even bad.These poor working conditions to some extent disturb the system.Here, we have designed some corresponding anti-jamming measures from the software and hardware for all kinds of interference,low visibility weather conditions (rain and fog weather), this design can provide specific and accurate information for the people on duty, to help to direct traffic crossing.