DIGITAL THERMOMETER WITH 8051

This is the project about sensing the temperature from environment and display it in LCD. We use 16x2 LCD for display.


LM35 :-
                We use LM35 temperature sensor for sensing the temperature from environment. It gives 10 milivolt on 1°C temperature when operating on 5 volts.






ADC0804 :- 
                    LM35 gives the analog signal for converting this into digital signal we use a 8 bit ADC IC ADC0804.










16x2 LCD :-
                       16x2 LCD is used to display the Temperature.   see more here......                                                                    
   LCD INTERFACING WITH 8051


8051 :-

           
Circuit Digram :-
       

pink lines - 12v
red lines - 5v
black lines - ground
blue lines - data

download this image and zoom in then you can see clearly all the connections.

Components Required :-

1N4007 diode - 1
330 0HM RESISTANCE - 2
10K OHM RESISTANCE - 2
10K OHM VARIABLE RESISTANCE - 2
150PF CAPACITOR - 1
33PF CAPACITOR - 2
10UF CAPACITOR - 1
1000UF CAPACITOR - 1
11.0592 MHZ CRYSTAL OSCILLATOR - 1
GREEN LED - 1

RED LED - 116X2 LCD - 1
12 volt battery upto 1.5 amp. -1
P89V51RD2 MICROCONTROLLER - 1
PUSH BUTTON - 1
ADC0804 IC - 1

LM35 - 1
7805 IC - 1
16x2 LCD - 1
MALE AND FEMALE CONNECTORS LINES
CONNECTING WIRES.

Code :-

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//Program to display temperature in Celsius and Farenheit scale.

#include<reg51.h>
#define sec 100
sbit rs = P3^0;
sbit rw = P3^1;
sbit e = P3^2;

sbit wr= P3^3;
sbit rd= P3^4;
sbit intr= P3^5;

int x=0, y=0,z[10],a[3]={0,0,0};

void delay(unsigned int msec )
{
    int i ,j ;
    for(i=0;i<msec;i++)
        for(j=0; j<1275; j++);
}

void lcd_cmd(unsigned char item)    // Function to send commands to LCD
{
    P2 = item;
    rs= 0;
    rw=0;
    e=1;
    delay(1);
    e=0;
    return;
}

void lcd_data(unsigned char item)    // Function to send data to LCD
{
    P2 = item;
    rs= 1;
    rw=0;
    e=1;
    delay(1);
    e=0;
    return;
}

void lcd_data_string(unsigned char *str)  // Function to string to LCD
{
    int i=0;
    while(str[i]!='\0')
    {
        lcd_data(str[i]);
        i++;
        delay(10);
    }
    return;
}

void shape()        // Function to make the shape of degree symbol
{
    lcd_cmd(64);
    lcd_data(2);
    lcd_data(5);
    lcd_data(2);
    lcd_data(0);
    lcd_data(0);
    lcd_data(0);
    lcd_data(0);
    lcd_data(0);
}
       
void convert()     // Function to convert the values of ADC into numeric value to be sent to LCD
{
    int    s;
    lcd_cmd(0x81);      
    delay(2);
    lcd_data_string("TEMP:");
    y=(((9*x)/5)+32);
    s=y/100;
    y=y%100;
    lcd_cmd(0x88);
    if(s!=0)
    lcd_data(s+48);
    else
    lcd_cmd(0x06);
    s=y/10;
    y=y%10;
    lcd_data(s+48);
    lcd_data(y+48);
    lcd_data(0);
    lcd_data('F');
    lcd_data(' ');

    y=x;
    lcd_cmd(0xc1);        //Setting  cursor to first position of first line
    delay(2);
    lcd_data_string("TEMP:");
    s=y/100;
    y=y%100;
    lcd_cmd(0xc8);
    if(s!=0)
    lcd_data(s+48);
    else
    lcd_cmd(0x06);
    s=y/10;
    y=y%10;
    lcd_data(s+48);
    lcd_data(y+48);
    lcd_data(0);
    lcd_data('c');
    lcd_data(' ');
    delay(2);
}

void main()
{
    int i,j;
    P1=0xff;
    lcd_cmd(0x38);        //2 Line, 5X7 Matrix display
    lcd_cmd(0x0c);        //Display On, Cursor blinking
    delay(2);
    lcd_cmd(0x01);        // clear screen
    delay(2);

    while(1)
    {
        for(j=0;j<3;j++)
        {
            for(i=0;i<10;i++)
            {
                delay(1);
                rd=1;
                wr=0;
                delay(1);
                wr=1;
                while(intr==1);
                rd=0;
                lcd_cmd(0x88);
                z[i]=P1/10;
                delay(1);
                intr=1;
            }
            for(i=0;i<10;i++)
            a[j]=z[i]+a[j];
        }

        a[0]=a[0]/3;
        a[1]=a[1]/3;
        a[2]=a[2]/3;
        x=a[0]+a[1]+a[2];
        shape();
        convert();
    }
}

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Calculations in above program are standard.

Pictures :-

Videos :-

 

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