#define DT A0
#define SCK A1
 
long sample=0;
float val=0;
long count=0;
int WEIGHT=0;
 
unsigned long readCount(void)
{
unsigned long Count;
unsigned char i;
pinMode(DT, OUTPUT);
digitalWrite(DT,HIGH);
digitalWrite(SCK,LOW);
Count=0;
pinMode(DT, INPUT);
while(digitalRead(DT));
for (i=0;i<24;i++)
{
digitalWrite(SCK,HIGH);
Count=Count<<1;
digitalWrite(SCK,LOW);
if(digitalRead(DT))
Count++;
}
digitalWrite(SCK,HIGH);
Count=Count^0x800000;
digitalWrite(SCK,LOW);
return(Count);
}
 
void setup()
{
 pinMode(6, OUTPUT); 
 pinMode(7, OUTPUT);
 pinMode(8, OUTPUT); 
 pinMode(10, OUTPUT);  
pinMode(SCK, OUTPUT);

delay(500);

test();
calibrate();
}
 
void loop()
{
count= readCount();
int w=(((count-sample)/val)-2*((count-sample)/val));

 WEIGHT = map(w,0,1000,0,255);
 analogWrite (6,WEIGHT);
}
 
void calibrate()
{
  digitalWrite(7, HIGH);

for(int i=0;i<100;i++)

{
count=readCount();
sample+=count;
}
sample/=100;

digitalWrite(7, LOW);
digitalWrite(8, HIGH);
count=0;
while(count<1000)
{
count=readCount();
count=sample-count;
}

delay(2000);
for(int i=0;i<100;i++)
{
count=readCount();
val+=sample-count;
}
val=val/100.0;
val=val/100.0; // put here your calibrating weight

digitalWrite(8, LOW);
digitalWrite(10, HIGH);
}
void test() {
for (int i=1;i<=255;i++)
{
analogWrite (6, i);  
delay (15);
}
for (int i=255;i>=1;i--)
{
analogWrite (6, i);  
delay (15);
}
}