Knock Lock
I had the issue of my roommates leaving the dorm door unlocked and leaving our valuables and safety vulnerable to intruders. Fortunately the dorms are quite safe but as we were moving to an off-campus apartment I wanted to develop a technical solution to increase our safety. A part of the issue was that my roommate’s wouldn’t carry their physical keys on them at all times so I developed the solution that requires no physical key.
The Knock Lock is a system that is attached to the inside a door and has the capabilities to unlock and lock it. The idea is that the system would automatically lock the door when it’s left unlocked while not interfering with the traditional (lock and key) use of the door. Generally adding another way to unlock a door decreases the security of the door, however this system is an addition rather than a replacement.
I programmed and constructed a prototype Knock Lock a using an Arduino Uno microcontroller. The prototype was fully functional: would unlock a deadbolt upon receiving the correct knock sequence. The prototype code included two different knock codes that could be switched with a button.
Arduino code is a language based on C++, I utilized 4 user-defined functions and 3 unique flow control structures. The code and video are embedded on this page. I plan to continue to refine this system before implementing it such as the following features: daily code switch, detection of whether the door is left ajar, ability to easily in punch in a new code, eliminating battery replacement/solar charging.