Temperature alarm system based on 51 microcontroller

Function:

Design a temperature alarm system that can set the upper and lower limits of the temperature. When the set value is reached, the buzzer will sound; the button setting has the functions of setting, confirming, canceling, reducing and increasing, and LCD1602 will display relevant temperature information in real time.

Setting interface:

When the temperature exceeds the set value, the buzzer sounds:

The temperature exceeds the set value and the buzzer sounds: The temperature exceeds the set value.

When the temperature is lower than the set value, the buzzer sounds:

Part of the program:

#include

#include "SETTEM.h" //Set the upper and lower limit header files for alarms

#include "Lcd1602.h" //LCD display module function header file

#include "DS18B20.h" //DS18B02 module function header file

#include "IntToChar.h" //Header file that stores integers converted to strings

#include "Alarm.h" //Alarm function header file

bit flag1s = 0; //1s timing flag

unsigned char T0RH = 0; //High byte of T0 reload value

unsigned char T0RL = 0; //low byte of T0 reload value

int key=0;

char Hint1[]={"Current temperature"};

void ConfigTimer0(unsigned int ms);

void main()

{

bit res;

int temp; //The current temperature value read

int intT, decT; //The integer and decimal parts of the temperature value

unsigned char len;

unsigned char str[12];

EA = 1; //Enable total interrupt

ConfigTimer0(10); //T0 timing 10ms

Start18B20(); //Start DS18B20

InitLcd1602(); //Initialize LCD

ConfigInt0(); //Set the temperature

while (1)

{

if (flag1s) //Update temperature every second

{

flag1s = 0;

res = Get18B20Temp(&temp); //Read the current temperature

if (res) //When reading is successful, refresh the current temperature display

{

intT = temp >> 4; //Separate the integer part of the temperature value

decT = temp & 0xF; //Separate the decimal part of the temperature value

len = IntToString(str, intT); //Convert the integer part to a string

str[len++] = '.'; //Add decimal point

decT = (decT*10) / 16; //Convert the decimal part of binary to 1 decimal digit

str[len++] = decT + '0'; //Convert decimal digits to ASCII characters

str[len++] = key + '0';

while (len < 6) //Use spaces to complete to 6 characters in length

{

str[len++] = ' ';

}

str[len] = ''; //Add string terminator

LcdShowStr(0, 0, Hint1); //The prompt is displayed on the LCD screen

LcdShowStr(0, 1, str); //The temperature is displayed on the LCD screen

}

else //When reading fails, an error message is prompted

{

LcdShowStr(0, 0, "error!");

}

Start18B20(); //Restart the next conversion

Alarm((float)temp*0.0625,Htem,Ltem);

}

}

}