Cryptap: A rhythm-based door lock

Step 2 Pre-existing hardware

I was very lucky that there was already so much installed. My room is ADA-accessible, and there were various pipes, electrical boxes and an electric door strike already installed. On removing the door strike out of curiosity, I found that it was not connected. There was a pipe from the door strike to a blank wall plate inside my room, and another pipe from there to a blank wall plate outside.

The door strike says it needs 24V@3A to operate, but I was able to get by with a 19V, 7.9A power supply I had. The door strike was polarized, so make sure you have the polarity correct!