Arduino Door Latch

Projects General Guidance
1

Hello. I have a door that swings inward. It has no lock, just a boring, ordinary handel.

I would like to make a latch for this door, so I could lock it from the inside electronically.

I CAN NOT drill into the door, screw stuff into the door, or tamper with the ACTUAL door in any way, shape, or form. Same goes for the wall around the door.

My first thought was to have a servo attached to the wall beside the door, and when its arm came down it would block the door from opening. When the arm was lifted, the door could open again. But there are 2 problems:

  1. How can I attach the servo to the wall sturdily, without tampering with the wall (See my previous point above)
  2. What kind of servo would not smash into bits when too much force is applied.

Nobody is going to be kicking down the door or anything. I just want to keep my family out so I can have some quiet time.... Don't we all? :confused:

Any help would be AWESOME! :slight_smile: :slight_smile: :slight_smile: (The servo idea was just my original thought, I am open to more suggestions.)

2

Make a box with a (stepper) motor inside. Use the motor and a threaded rod to push a heavy bar out the side of the box a couple of centimeters. The bar has to be secured at the sides so that it doesn't move sideways enough to damage the mechanical workings. Make the box heavy by filling it with rocks, sand, water, whatever. Position the box beside the door so that when the bar comes out, it blocks the door from opening. The box is acting like a door stop. If someone pushed hard enough, the door would open, but you are apparently only wanting to provide enough resistance to remind family members that you aren't wanting visitors at the moment.

It wouldn't have to just be a "box". You could design it as a cabinet, book case, clothes hamper, or whatever.