Smoke alarm system based on labview

Functions: Monitor gas concentration in real time through the host computer and compare it with the alarm threshold set by the host computer. If the gas concentration exceeds the alarm value, the upper and lower computers will alarm at the same time. Change the gas alarm value in real time and transmit it to the lower computer for judgment through the host computer.

Circuit diagram: Refer to ADC0809 datasheet and MQ-2 gas sensor module parameters. The sensor outputs 0~5V analog voltage according to the gas concentration and inputs it to the analog input terminal of 0809.

Debugging: Use the serial port debugging assistant to check the correctness of data transmission.

program:

#include

#include

#include

#define uchar unsigned char

#define uint unsigned int

sbit CLK=P3^3;      //Clock output

sbit ST=P2^0; //Start conversion input signal

sbit OE=P2^1;    //Enable output signal

sbit EOC=P3^2;               //Using interrupts, the priority is lower than T0 interrupt

uchar DATA; //Store A/D conversion data

sbit Beep=P2^7;

uchar aa;

void delayxms(uint x) //delay

{

uint i,j;

for(i=x;i>0;i--)

for(j=110;j>0;j--);

}

void delayxus(uint x) //delay xus

{

uint i;

for(i=x;i>0;i--)

_nop_();

}

void init(void)

{

TMOD=0x22; //Timer 0 automatically reloads 8 bits to generate CLK, and timer 1 sets serial port parameters

TH0=237; //50kHZ

TL0=237;

TL1=0xf3;

TH1=0xf3;//2400bps

TR1=1;

TR0=1;

SM0=0;

SM1=1;

EA=1;

ET0=1;

EN=1;

REN=1;

ST=0;

OE=0;

}

void ADC0809()

{

ST=0;

OE=0;

//LE=1;P0=0x00;LE=0;   //Select channel

delayxus(2);

ST=1;   //Start AD conversion

delayxus(10);

ST=0;

delayxus(200);

while(EOC==0);   //When EOC=1, the conversion is complete

YOU=1;

DATA=P1; //DATA is the data after AD conversion

delayxus(20);

OE=0;

}

[page]

void main()

{

Beep=1;

heat();

while(1)

{

ADC0809();

if(aa==49)Beep=0;

else Beep=1;

delayxms(200);

}

}

void serial() interrupt 4

{ uint r;

RI=0;

r=SBUF;

aa=r;

if(r==48||r==49)

{

   SBUF=DATA; //Send to the host computer

while(!IF);

IF = 0;

}

}

void T0_time() interrupt 1

{

   CLK=~CLK;

}