TL;DR
The Secret Knock Activated Drawer Lock is a fun DIY project that allows you to unlock a drawer using a specific pattern of knocks. Instead of a traditional key, this lock utilizes a hidden mechanism that responds to a sequence of taps, making it discreet and engaging. A solenoid latch secures the drawer, while a piezo buzzer detects the knock pattern. A small microcontroller, the Trinket, processes the knocks and compares them to a pre-set secret pattern to grant access.