AT89C51 Digital Thermometer with LCD - help with code in C

[dallurajan]

help plz

i am doing project on the digital thermometer using LM 35, ADC 0804, AT89C51 and LCD . plz help me with the source code in C.

 

[issaiass]

help plz

Pseudocode is as follows in the description:
First: Amplify and adjust LM35 resolution to your ADC resolution (lm35 resolution is 10mV/ºC)


1 - Set system frequency of your microcontroller (using your PLL Module if you have it)
2 - Set ADC to the channel that you want is really simple if you use it a microcontroller with adc.
3 - Read samples every "n" msec
4 - Convert ADC value to temperature using its resolution, i.e. if my ADC and sensor are amplified to couple the same resolution (i will use 20mV/C) then a 320mV are 16ºC if my adc is 5V max and i have my adc value is 0x10... my equation would be-
T = ADCvalue
5 - You must use a Hex to dec routine to display on your LCD

 

[dimas_lilik]

May be this sample program can help you:

#include <reg52.h>
#include <stdio.h>

void timer0int(void);
char *Puts(char* str);

float read_temp1(void);
float read_temp1_filter(void);


char cputick;
char buffer[24];
char pulseE;

char timer3;
char temp;
char vout;
int x1,x2,x3,x4,x5;

sbit RS=P1^6;
sbit E =P1^4;
sbit RW=P1^5;

sbit CLK=P1^2;
sbit Data=P1^1;
sbit CS=P1^3;

sbit CHG=P3^0;

int readADC(char n)
{
	int k;
	char i,channel;
	k=0;

	CS=0;

	if(n==0) channel= 0x0d;
	else channel=0x0f;

	for (i=0;i<4;i++)
	{
		CLK = 0;

		if(channel&8) Data =1;
		else Data = 0;
		CLK =1;
		channel <<=1;
	}

	Data = 1;
	CLK =0;

	for(i=0; i<12;i++)
	{
		k<<=1;
		CLK =1;
		CLK=0;
		if(Data) k|=1;
		else k &=~1;
	}
		CS =1;

		return k&=0xfff;
}


void timer0int(void) interrupt 1 using 1

{
 TH0 |=0xdc;
 cputick++;
}


pause(int j)
{ int i;
  for (i=0;i<j;i++)
  continue;
}


pulesE()
{
  E =1;
    ;
  E =0;
 }


void delay(int m)
{
	int j;
	for(j=0;j<=m;j++)
	continue;
}

LCDWI (char n)
{   
  RW =0;
  RS=0;
  E =0;
  P0=n;
  E =1;
  E =0;
  pause(50);
}


LCDWD(char n)
{
  RW=0;
  RS=1;
  E=0;
  P0=n;
  E=1;
  E=0;
  pause(50);
}

print_LCD(char a,char *s)
{
LCDWI(a);
while(*s != 0)
LCDWD(*s++);
}


i_LCD()
{
  RS=0;
  E=0;
  P0=0x30;pulesE();delay(10);pulesE();delay(1);pulesE();delay(1);
  P0=0x20;pulesE();pulesE();pulesE();
  LCDWI(0x38);
  LCDWI(0x0c);
  LCDWI(0x06);
  LCDWI(1);
  delay(50);
}

print_ADC()
{
 char buffer[20];
 if(++timer3<50)
 {
  timer3=0;
  sprintf(buffer,"%0.1fC   %0.1fF",read_temp1_filter(),read_temp1_filter()*9/5+32);
  print_LCD(0xc0,buffer);
  }
}

int low_pass_filter1(void)
{
	x5=x4;
	x4=x3;
	x3=x2;
	x2=x1;
	x1=readADC(0);
	return(x1+x2+x3+x4+x5)/5;
}

float read_temp1_filter(void)
{
	return(0.0323*low_pass_filter1()-15.615);
}


void main()
{
 i_LCD();
 print_LCD(0x80,"LCD Thermometer");
 TMOD |= 0x01;
 TR0 = 1;
 cputick = 0;
 EA = 1;
 ET0 = 1;
 
  for(;;)
 {
	while(!TF0)
	continue;
	TF0=0;
	print_ADC();
 }
}

 

[mike.11]

hi
here is the code in for digital thermometer using microcontroller

//Program to make a digital thermometer with display in centigrade scale

#include<reg51.h>
#define port P3
#define adc_input P1
#define dataport P0
#define sec 100
sbit rs = port^0;
sbit rw = port^1;
sbit e = port^2;

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

int test_intermediate3=0, test_final=0,test_intermediate1[10],test_intermediate2[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 command to LCD
{
dataport = item;
rs= 0;
rw=0;
e=1;
delay(1);
e=0;
return;
}

void lcd_data(unsigned char item) //Function to send data to LCD
{
dataport = item;
rs= 1;
rw=0;
e=1;
delay(1);
e=0;
//delay(100);
return;
}

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

void shape()     // Function to create the shape of degree
{
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;
test_final=test_intermediate3;
lcd_cmd(0xc1); 
delay(2);
lcd_data_string("TEMP:");
s=test_final/100;
test_final=test_final%100;
lcd_cmd(0xc8);
if(s!=0)
lcd_data(s+48);
else
lcd_cmd(0x06);
s=test_final/10;
test_final=test_final%10;
lcd_data(s+48);
lcd_data(test_final+48);
lcd_data(0);
lcd_data('c');
lcd_data(' ');
delay(2);
}

void main()
{
int i,j;
adc_input=0xff;
lcd_cmd(0x38); 
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);
    test_intermediate1[i]=adc_input/10;
    delay(1);
    intr=1;
   }
   for(i=0;i<10;i++)
   test_intermediate2[j]=test_intermediate1[i]+test_intermediate2[j];
  }

test_intermediate2[0]=test_intermediate2[0]/3;
test_intermediate2[1]=test_intermediate2[1]/3;
test_intermediate2[2]=test_intermediate2[2]/3;
test_intermediate3=test_intermediate2[0]+test_intermediate2[1]+test_intermediate2[2];
shape();
convert();
}
}

you can also check this link out for **broken link removed**