Taking MSP430F149 as the main control chip, an intelligent fire alarm system with high precision, high integration and ultra-low power consumption is designed. Taking the ambient temperature and smoke concentration as the basis for judging the fire, the fire early warning is completed. It is mainly composed of single chip microcomputer control module, clock module, smoke concentration measurement module, DS18B20 temperature measurement module, audible and visual alarm module, 1602 LCD module and power supply. And the system takes MSP430F149 as the lower computer to complete data acquisition, preprocessing and control of field devices, and takes PC as the upper computer to complete various complex data processing and control of single chip microcomputer. The designed intelligent fire alarm system has high reliability, stability and accuracy, has high sensitivity to different types of fires, and achieves the purpose of reducing the false alarm rate.

 Temperature measurement module:DS18B20 temperature sensor, which supports “one line bus” interface, has strong anti-interference, simple external circuit and high accuracy, is used to measure the temperature in real time. Among them, DS18B20 pin 2, namely DQ, is connected to p2.0 pin of MSP430F149, as shown in the figure.

  

temperature measurement

  Audible and visual alarm module:The buzzer will give an alarm indication tone when the microprocessor judges that there is a fire. Due to the limited driving ability of I / O port of single chip microcomputer, PNP transistor 2n5401 is selected to form a transistor driving circuit to drive the piezoelectric buzzer.

  

Sound and light alarm module diagram

  LCD module:Display time, measurement temperature, smoke concentration and other parameters on the LCD module, so that we can more easily read out the current temperature value and smoke concentration value.

  

LCD module diagram

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