Arduino Project Handbook

PROJECT 9: SECRET KNOCK LOCK

FOR CENTURIES CLANDESTINE GROUPS HAVE USED SECRET KNOCKS TO PREVENT UNAUTHORIZED ENTRY. LET’S BRING THIS SYSTEM INTO MODERN TIMES, BY CREATING OUR OWN ELECTRONIC GATEKEEPER.

PARTS REQUIRED

• Arduino board

• Breadboard

• Jumper wires

• Tower Pro SG90 9g servomotor

• Piezo buzzer

• 3 LEDs

• 1M-ohm resistor

• 3 220-ohm resistors

LIBRARIES REQUIRED

• Servo

HOW IT WORKS

In this project, you’ll make a circuit that moves a servo arm to unlock a box or door when you provide the correct secret knock. So far we’ve been using ...