Design of digital temperature monitoring and alarm system based on DS18B20 single chip microcomputer [LCD1602 display + Proteus simulation + C program + paper + key setting, etc.]

notes ： Get the full set of resources , Please refer to the following description …

The design requirements
1. The accuracy of the measured temperature value is ±1℃;
2. The allowable error range of the system is 1℃ within ;
3. The system can preset the temperature value by the user , The temperature range is －55℃～＋125℃;
4. adopt DS18B20 Sensor and system connections , Can detect the temperature of the site in real time and accurately ;
5. Pass the temperature value detected on site in real time LCD1602 The LCD displays ;
6. Alarm temperature setting and alarm ： The alarm temperature can be set as required , And when the alarm temperature is reached, an alarm prompt will be sent ;

System Overview
The system adopts an improved temperature sensor DS18B20 As a detection element , The temperature range is -55～125ºC, The highest resolution can reach 0.0625ºC.DS18B20 The measured temperature value can be read out directly , And the three wire system is connected with the single chip microcomputer , Reduced external hardware circuits , It has the characteristics of low cost and easy to use .

This design is based on AT89C52 Simulation design of temperature monitoring system based on single chip microcomputer , System USES DS18B20 As a temperature monitoring element , measuring range -55℃-～+125℃, Use LCD1602 The LCD module displays the measured temperature value and the set upper and lower limits of temperature , The key module is used to set the upper and lower limits of temperature alarm . If the currently obtained temperature is not within the upper and lower limits of the set temperature , Buzzer alarm ,LED The indicator light is on , Indicates the current alarm message .

System consists of 4 Component composition , They are AT89C52 Minimum system of single chip microcomputer （ Including reset circuit and crystal oscillator circuit ）、DS18B20 Temperature acquisition module 、LCD Display module 、 Key setting module and alarm module , Its design framework is as follows .

Simulation circuit diagram


The simulation results run
When from DS18B20 When the collected temperature is lower than the lower temperature limit , The simulation results are shown in the figure below , Known blue LED The indicator light is on , Buzzer alarm .

part C Program

 The main program 
void main()

{
    

init();//LCD initialization 

Init_time();

Init_DS18B20();//DS18B20 initialization 

while(1)

{
    

if(s1==0||s1num>=1)

{
    keyscan(); TR0 = 0; D1 = 1; D2 = 1;}// Key scan 

else

{
    

ReadTemp();// Read temperature value 

write_temp_value(0,temp_value);//LCD Display temperature value 

comp();

}

}

}

void delay(uint z)

{
    

uint x,y;

for(x=z;x>0;x–)

for(y=110;y>0;y–);

}

/LCD Initializer ***/

void init()

{
    

lcden=0;

lcdrw=0;

write_com(0x38); // Set up 16x2  Show 5x7  Lattice ,8  Bit data interface 

write_com(0x0c); // Set whether to display the cursor at the beginning 

write_com(0x06); // After writing a character, add... To the address pointer 1

write_com(0x01); // Display reset data pointer reset 

write_com(0x80); // Place the data pointer at the first word of the first line ,

write_com(0x80+9); // Defines the current pointer position 

write_data(‘H’);

write_data(’:’);

write_data(’+’);

write_data(‘2’);

write_data(‘0’);

write_data(0xdf);

write_data(‘C’);

write_com(0x80+9+0x40); // Defines the current pointer position 

write_data(‘L’);

write_data(’:’);

write_data(’+’);

write_data(‘1’);

write_data(‘0’);

write_data(0xdf);

write_data(‘C’);

h=0x14;

l=0+0x0a;

D1=1;

D2=1;

figh=0;

figl=1;
}

The content of resource sharing includes
（1） be based on DS18B20 Digital temperature monitoring system Proteus Simulation paper 【 Full version 】;
（2）Proteus Simulation file ;
（3）Keil C Language program file ;
（4） References （DS18B20、LCD1602 Manuals, etc ）;
（5）Visio Flow chart file ;

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Resource acquisition method
Resource acquisition method
Resource acquisition method
Important things are to be repeated for 3 times ！！！！！！！！！！！
Because this design is the author's original design , Get a complete paper report 、Keil C Program 、Proteus Simulation 、Visio Flow chart documents and references .

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