Using Millis with optical encoder

Projects Programming
11

Here's your hanging offense :grinning:

if( counter != temp ){
  Serial.println (counter);
  temp = counter;
  }

Counter is touched in an interrupt and it's four bytes. Consequently, it may change behind the scenes while you're looking at it. What you need is:

noInterrupts() ;
if( counter != temp ){
  Serial.println (counter);
  temp = counter;
  }
interrupts() ;

Although it would be better to move the Serial.print out of that section.