Secret Knock Detecting Door Lock

Here’s a fantastic project using an arduino, a motor, and a piezo sensor which allows you to both record and detect knocking patterns to unlock a door. The video below does a fantastic job of demonstrating how it works: It’s completely mobile and can be suction cupped to any dead bolt. Press a button to record a new sequence. Upon detecting the correct sequence of knocks, the motor turns the lock open. Brilliant!

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For more details on the project including detailed photos and code, check out the project build. We have hundreds of the best Arduino projects for your inspiration: