Slide this tool under most doors to grab the handle on the other side and open it.

One of my friends at MIT is very involved in the hacker culture there. He described a tool hackers there use to open doors that slides under a door and pulls on the handle on the other side. This makes loads of sense as most doors are only locked from one side; you want to keep people out, not in. He didn't give any details at all other than that the tool slides under the door. I was interested, and left this project on the back burner for a few months.

Fast forward. I'm at Carnege Mellon now, and all the noob freshman are locking themselves out. They have to wait for about an hour for the Campus Police to come open their door. Now, at MSSM I had a special secret keycard that allowed me to open room doors for the nubcake first years who locked themselves out. here, I don't have that luxury. I was reminded of the MIT hackers' solution.

I originally posted this on my blog. I love it when people read my stuff.

Step 1: Choosing Material: It's Harder Than It Looks

For such a simple device, the actual design of it is increasingly complicated. Originally I had planned to use a rigid piece of metal that would enter on the far side of the door from the handle, turn and force the handle down like a lever. An hour's worth of wandering around Home Depot proved that this was unrealistic as nothing would be stiff enough to not bend when pushing down on the handle. Instead I found some 6 gauge copper wire.

6 gauge copper wire is perfect for this problem for two reasons. Number 1, it is stiff enough to maintain a shape once bent despite a reasonable amount of pressure applied to it. Number 2, it is bendy enough that you don't ruin your soft typing fingers on it. 4 gauge: too hard. 8 gauge: too soft. 6 gauge: just right.

Step 2: Bending the Wire Into Shape

The importance of this shape is that the wire will appropriately slip under the door when laid flat, flip up when turned with the back handle, and lean against the door so it slides between the handle and the door on the other side.

Make the hook that will grab onto the handle on the inside first. If you roll your wire up, you won't even need to unbend this part of the wire at all, just make your coil the same diameter as the hook.

Stand the wire on the hook on the floor by the handle on the outside. Since the handle on the inside is the same height from the floor, you can make the second bend at the correct height to grab onto the handle.

Finish the door opener by making a fourth bend to create a lever to swing the wire up over the handle on the inside.

Step 3: Videos! the Tool in Action.

From outside the door:

Step 4: Finishing Touches.

Adding a 1/4" ten thread per inch bolt to the wire makes for a tripod that's good in a pinch. You never really know when you're going to need to take a clear picture, and the flexibility of the tool allows you to keep it in your pocket or backpack pretty easily.

Be warned that once word gets out that you can let people into their rooms, everyone will want you to let them in. I got several calls in class from people who locked themselves out. It becomes a mess. Fortunately, copper isn't terribly durable after all those bends, and the tool broke on its own after a while. It's good to be able to relax now.

I originally posted this on my blog. I really appreciate it when people read my posts! Thanks to Matt for reminding me why I love Instructables.