can i use pin0 or pin 1 to controll a relay?
i been reading many webs, most of the answers are voiding pin0, and use pin1 , is that mean pin 1 is same a regular digital pin that can do i/p and o/p?
and also saw people saying that if im not using serial monitor, i can use both, is it right?
Yes, you can use them as regular pins. It is,however, normally best to avoid them unless necessary as using them has been known to cause problems when uploading new sketches. It is usually easy to get around said problem by pressing and holding reset before uploading the new sketch, releasing it just as the IDE reports the size of the sketch.