Simple temperature counting code tube display based on 51 single chip microcomputer

1. Hardware Solution

This system uses 51 single-chip microcomputer to control the temperature sensor DS18B20 to detect and display the temperature in real time, which can realize rapid measurement of ambient temperature.

The hardware is based on a microcontroller, and consists of an external clock circuit, a reset circuit, a temperature measurement circuit, and an LED display circuit. As shown in the figure:

2. Design function

(1) The DS18B20 temperature sensor is used for temperature measurement, with a temperature range of -55~+125℃, an accuracy of 0.1℃ (displayed to one decimal place), and an error of ±0.5℃;

(2) Use 0.56-inch four-digit common anode digital tube to display the current temperature;

(3) There is a reset button.

3. Design Schematic

(1) The schematic diagram is mainly designed using AD software, as shown in the figure:

(2) The Protues simulation diagram is as follows:

(3) The PCB diagram is as follows:

4. Software Design

Main program source code

/*****Main function*****/

void main()

{

uc z; //Define variables for for loop

for(z=0;z<100;z++) //Loop 100 times to read the temperature and display the boot screen to prevent the boot screen from displaying 85

{

Disp_init(); //Startup initialization display

check_wendu(); //Read temperature

}

while(1) //Enter while loop

{

check_wendu(); //Read temperature

for(z=0;z<10;z++) //display 10 times

Disp_Temperature(); //Call display function

}

}

/*****Display temperature subroutine*****/

void Disp_Temperature() //Display temperature

{

if(qian==0)   //thousands digit equals 0

{

if(fuhao==1) // is negative temperature

P0=0x7f; //Display-

else   // is a positive temperature

P0=0xff;   //not displayed

P2=0xfd;   //Select the first position

Delay(10); //delay

P2 = 0xff; //Close bit selection

}

else if(qian!=0)   //thousands digit is not equal to 0

{

P0 =~led[qian];   //Display thousands of data

P2 = 0xfd;   //Open the first bit selection

Delay(10);   //delay

P2 = 0xff;   //Close bit selection

}

if((bai==0)&&(qian==0))//both the hundreds and thousands are 0

{

P0=0xff; //not displayed

P2=0xf7; //Open the second bit

Delay(10); //delay

P2=0xff; //Close bit selection

}

else if((bai==0)&&(qian!=0))//The thousandth digit is not equal to 0, the hundredth digit is equal to 0

{

P0=~led[bai]; //Normal display of hundreds digit data

P2=0xf7; //Open the second bit

Delay(10); //delay

P2=0xff; //Close bit selection

}

else if(bai!=0) //hundreds digit is not equal to 0

{

P0=~led[bai]; //display hundreds

P2=0xf7; //Open the second bit

Delay(10); //delay

P2=0xff; //Close bit selection

}

P0=~led_dian[shi]; //Display ten-digit data

P2=0xdf;   //Open the third bit

Delay(10);   //delay

P2=0xff;   //Close bit selection

P0=~led[ge];      //Display the unit data

P2=0x7f;   //Open the fourth bit

Delay(10);   //delay

P2=0xff; //Turn off the display

}