send serial selectively (only when active)?

Using Arduino Programming Questions
4

Could I ask for further help in applying a delta function; this way I can send data only when the delta exceeds a set threshold.

Sure.

int currVal;
int prevVal = 0;

void loop()
{
   currVal = analogRead(myPin);
   if(abs(currVal - prevVal) > 5)
   {
      Serial.write(currVal);
      prevVal = currVal;
   }
}

This will send a value only when the difference between the current value and the previous value is greater than 5, positive or negative.

You might want to divide the fsr reading by some amount, say 5, and then send each (different) value without worrying about a range. Either one will work.