Start and Stop Stepper with Accel Library

Projects Programming
3

This part is wrong.

      digitalWrite(relayPin, relayState = !relayState);

It won't change between the two states like you seem to think.

Better be explicit than this fancy "alter a variable in the middle of a function call" stuff.

  if (relayState == relayOn)
     relayState = relayOff;
  else
     relayState = relayOn;

  digitalWrite(relayPin, (relayState == relayOn) ? HIGH : LOW);