8051 Project | Temperature Control System using LM35

• Temperature sensor able to sense environment temperature
• DC fan will spin according to current temperature, Low, Medium, High
• LCD to display current temperature and fan speed
• User able to control fan speed using push putton

• I should use TIP102 for interfacing to DC Fan but since Proteus didn't have TIP102 in library then i use #2 TIP122 to replace it.
• SW1 is toggle button to control ON/OFF circuit

I dont see any clock generating circuit associated with ADC.. usually we use 555 timer IC to generate clock to ADC IC

Click to expand...

#include<reg52.h>

#define input P1

sbit output = P3^1;

sbitwr= P3^3;
sbitrd= P3^4;
sbitintr= P3^5;

voidpwm(int i);

void delay(unsigned int n )
{
int i ,j ;
for(i=0;i<n;i++)
for(j=0; j<350; j++);
}


void main()
{
int temp
Input =0xff;
wr=0;

rd=0;
intr=1;

while(1)
{
rd=1;
wr=0;
delay(2);
wr=1;
while(intr==1);
rd=0;
temp=input;
intr=1;



if(temp>0&&temp<10)
{
while(temp >0&&temp <10)
outs=0;
}

else if(temp>15&&temp<30)

{ while(temp >10&&temp <30)
pwm(5);
}
else
{
while(temp >30)
pwm(10);
}
}
}


voidpwm(int i)

{
intj,k;
outs=1;
for(j=0;j<i;j++)
delay(5);
k=10-i;
outs=0;
for(j=0;j<k;j++)
delay(5);
}

Click to expand...

Temperature of surrounding is sensed by temperature sensor and it send it's o/p as DC voltage to Analog to digital Converter 0808 through which we give 8 bit value of that voltage to microcontrller 8051.After it's processing it is displayed in LCD ...

Click to expand...