Hi, I'm doing an access control system, my question is that if the release button is connected in the circuit of switching, the button is normally closed, so the arduino will always send a pulse of 5v so the optocoupler switch constantly, and so be able to energize the electromagnetic lock. When the user that is inside the local press the exit button, comuntacion circuit is open so it not may energize the lock, so door frees her and user can exit. When the button returns to its State energizes this mode electromagnetic lock if the user closes the door, this already is not opened.
Is it so? or exit button goes straight to the arduino and has to be programmed by the arduino to unlock the door?