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!
Components REQD.:
01) Arduino
02) Piezo speaker
03) High Torque Geared Motor (5V rated)
04) Pushbutton
05) LEDs (green & red)
06) npn Transistor (P2N2222A)
07) Rectifier Diode (1N4001)
08) Resistance 2.2 kOhm
09) Resistance 1 MOhm
10) Resistance 10 kOhm
11) Resistance 220 Ohm [x2]