I'm trying to make a base with a hidden door that can be opened from the inside and outside. I was wondering if there was a way of making a circuit that could be operated from two different switches allowing me to operate the door from the inside and outside. Here is a picture that shows the hidden door in its open status.Sorry its a bit blurred, but hopefully you can see what's happening.
What you need is an XOR circuit.
An XOR circuit allows either switch to change the state of the door (open/closed). This means the door can be opened or closed using either switch and it doesn't matter if the other switch is up or down.
I have done this but it can be tedious trying to get the Redstone to laid out correctly. In the diagram in the link A would represent a switch on one side of the door and B would represent a the switch on the other side.