摘要城市轨道交通凭借其高效节能的特性，成为城市公共交通发展的主流趋势。然而，对城市轨道交通进行研究发现，因为其人员密度大、流量多，当火灾在城市轨道交通车厢中蔓延时，与其它火灾情形比较而言，城市轨道交通的受灾情形要更加难以把握，造成的危害也更加可怕。75960

本系统主要针对火灾初期的烟雾浓度和温度进行探测，并且通过声光来报警火灾信号。概要的工作过程为：温度传感器（DS18B20）负责对车厢中的温度信号进行精确采集，半导体电阻式烟雾传感器（MQ-2）采用过电阻分压的方式与模数转换芯片（ADC0832）连接来检测车厢中的烟雾浓度信号，以上两种被探测得到的火灾信号经单片机数据处理过后显示在显示屏LCD1602上。一旦系统检测到车厢中温度或烟雾浓度达到设定的TOP值，蜂鸣器会发出蜂鸣声，红色二极管也会闪烁。当火灾初期烟雾浓度或者温度大于设置值时，系统自动进行声光报警或人为按动报警（自动报警处于故障情况下采用人为报警）。同时，也可以人为的通过按键取消错误的火灾报警。

本设计选用的主控芯片价格低廉，相对于其它火灾报警系统来说它更加节能、体积小、控制方便、运行可靠，是一种能够满足城市轨道交通对火灾精确探测的可靠系统。

该设计有图16幅，参考文献21篇。

毕业论文关键词：单片机  温度传感器  烟雾传感器  LCD1602  火灾报警

Design of Fire Detection System for Urban Rail Transit

Abstract Urban rail transit has become the main development trend of urban public transport by virtue of the characteristics of smooth, efficient, reliable and so on。 However, due to the research on urban rail transit, because of its high density, traffic, compared with other ground fires, disaster situation in urban rail transport is more difficult to control and the harm is even more terrible when the fire in the urban rail transit operation occurs 。

The system is mainly aimed at the early fire smoke and temperature probing , then it alarms the fire signal by sound and light。 The summary of the work process is: The temperature sensor (DS18B20) is responsible for collecting the temperature signal , the smoke sensor (MQ-2) is connected with the analog digital conversion chip (ADC0832) to detect the smoke signal in the car, Then the above two kinds of detected electrical signals is displayed on the LCD1602 by the microcontroller (STC89C52)。

Because the temperature and smoke concentration are certain, the temperature and smoke concentration of the system TOP value is set directly through the program written in the implementation。 Once the system detects the temperature or smoke compartment concentration reached TOP, the buzzer will produce a beep and red diode flashes。 When the initial fire smoke concentration or temperature is greater than the set value, Automatic alarm alarm system (automatic or artificial press alarm in the case of failure by human alarm) are working。 At the same time, it can also be artificially through the button to cancel the wrong fire alarm。

The design use low cost chip STC89C52 as control chip。 Compared with other systems, it has low power consumption, small size, convenient control and reliable operation。 It is a reliable system that can meet the accurate detection of fire in urban rail transit。

Key Words: SCM  Temperature Sensor  Smoke Sensor  LCD1602   Fire Alarm 

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摘  要 III

Abstract IV

目录 V

图清单 VII

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