This secret bookcase door project got taken a little farther than most. After building a bookcase door that slides into a false wall cubby, user Kirzbleen at Instructables added an actuator with programming to open the door automatically. This secret door took months to plan an build, but the overall result it perfect.
The door is programmed to open when a secret book is pulled, or when a certain knock is detected. There is also a push to exit button on the back side of the door. I’d want to make sure there is some kind of safety latch I could pull to disengage the linear actuator, just incase of power outage or fire.