This is a video demonstration of the apartment buzzer entry system that Paweł Zadrożniak hacked so he can use a secret passcode to buzz himself into the complex without using a key or someone else being home to answer the buzzer's call. In his own words while I order one of those fake rock key stashes on Amazon:
I still have an annoying analog entry phone in my flat. It does not have the numeric keypad to type the passcode and enter the staircase. I am too lazy to open the block door with a key every time I come back home, but this can be solved easily. Of course I did not mean the replacement of the entry phone with a new, digital one - that would be too easy and too obvious. Here's my quick weekend project - analog entry phone hack, which opens the door after ringing in the secret passcode consisting of short and long rings. Traditionally, I have added some useless functionality like PCM audio playback from the SD card to make it more fun. It can play some samples, e.g. from retro games, an Arnie movie quote or... a barking dog when the guest or postman calls.
Pretty clever. My apartment complex used to have a numeric passcode you could use to buzz yourself into the building but people were giving it away to pretty much anybody who would listen so they deactivated it. Now you have to use a key or have the buzzer's call sent to your cell phone so you can buzz yourself in, which is handy. That way as long as I have my cell phone I can let myself into the building without a key. I forgot my phone though, so I'm going to need you to climb up to my balcony and squeeze through the kitchen window. Now listen: once you're in immediately grab a can of dog food and roll it under the sofa, or my dog will attack you. "Wait, what?!" Here, I'll give you a boost.
Keep going for the video. Source code to do the same thing yourself HERE.
Thanks to Fanfan, who agrees the easiest apartment complex entry hack is a really strong kick.