Yesterday my room mate Neil bought a large bottle of vodka at the grocery store. When he got home he found that the store had forgotten to take the anti theft device off. Its a black cylinder over the top of the bottle that prevents it from being opened and illicitly consumed.
Being an engineer my mind totally latched on to this problem. Of course we needed to get it off to drink the vodka but I really wanted to take it apart and understand how it worked. It felt like real world encryption. The bottle cap was trying to prevent us from getting the vodka out of the bottle.
Around the top of the cylinder were four slots that are used to remove the device with a special tool at the store. We first tried to insert things in duplicate whatever tool they used. But of course it wasn't that simple.
So next I used brute force to pry off the outside cover. I just used pliers to remove the plastic along one side. Once the cover was off it was both illuminating and frustrating. Of course it still wouldn't come off but now I could see some of the locking mechanism.
One piece on the bottom came off rather easily. But it was still locked. Pried apart the four arms on the top. Still locked. Finally found the two main pieces were held together by two tabs on either side. Pushing both in finally freed the vodka.
I'm writing this because I wanted to remind myself of the experience. Even after it was unlocked I was still interested in how it would be properly unlocked. I pieced it back together and pictured how it should work. Total I probably spent an hour and a half on the anti theft device. My room mate and I traded theories, made jokes, and laughed a lot. Its not something most people would enjoy but it stimulated my brain in just the right way.
I just wish I would've taken pictures as it was coming apart. :-)