- Surprise guests with an apparently closed room as they walk in
- Give them a riddle to figure out how to open the hidden door/wall
- Keep the area this occupies to a functional minimum so it doesn't take up too much actual entertaining space
Step 1: Planning the Layout
We decided that walking in from the front door, into a tiny room with only walls wouldn't seem very plausible. To help sell the illusion we hung a door in front of you as you walk in, but boarded it up, so the room appeared as a small vestibule which was no longer passable. We left the knob off this door, just to keep guests from trying to go through it (despite the boards). Which leads me to a point about safety...
Step 2: Framing and Safety
For the section of the wall that makes up the secret door, we used lighter materials so the job of moving it would be easier on the motor. It consists of just one 2x4 on the edge where it hinges, a 1x3 across the top, a 1x4 across the bottom, and a lightweight 2x3 steel stud on the side that moves. Since this section was light, just two hinges were used to connect it to the other framing.
There's about an inch gap at the top and bottom of the framing of this section, so there's plenty of clearance to move. The gaps would be covered once the "walls" were added.
Step 3: Walling it in
You could do any faux paint finish inside - we just painted everything white to blend with our existing doors and (real) walls.
Step 4: Adding the Wheel and Motor
The wheel is a hard rubber wheelchair wheel salvaged from some past robotics projects.
The wheel and motor were mounted so the wheel extends below, and supports, the bottom of the door framing.
Step 5: Electrical Work
To open the door from inside the room, two limit switches were mounted just under the base of a statue (see the photo). The switches are wired as "normally closed". When the statue is resting on the switches, they are open, and they become closed when the statue is tilted. Two switches (rather than one) were used because it was an easy way to tie into the existing circuit with the DPDT switch.
Step 6: Finishing Touches
We marked the swing of the door with an arc of gaffers tape on the floor. This would keep our guests aware of not standing too close as more people come in.
The final touch was a small riddle inside to give guests a clue of how to enter.