Can I simply unplug the Arduino usb if serial communication is active? So, after the sketch is uploaded, and I want to turn the Arduino off while it is running a sketch, all I have to do is unplug it.
Should be safe as long as nothing is uploading.
But I wonder, if I use serial communication between the Arduino and my Computer in a sketch, does it harm either if I simply unplug it?
if the sketch is uploaded, it wont hurt it to unplug. Just give it another source of power and it will run its sketch.