Secret Knock Lock
Electronics
Beginner
Arduino Uno
Arduino C++
About this project
KnockCipher turns a ₹10 piezoelectric disk into a secret knock security system. Tap the correct pattern — exactly 3 knocks within 4 seconds — and the LCD shows ACCESS GRANTED with a happy tone and green LED. Knock the wrong number of times and the system fires an alarm: red LED flashing, buzzer screaming, LCD showing INTRUDER ALERT. A button arms and disarms the system. The system auto-rearms after each access or alarm. No WiFi, no cloud, no RFID — the only key is the rhythm of your knuckles on the desk. This project teaches analog input from non-standard sensors, state machine programming, threshold detection, and timing — core skills that appear in industrial vibration monitoring, smart door locks, and seismic sensing systems.
What you get
- Complete, commented source code
- Full components list with quantities
- Pin-by-pin wiring guide and connection table
- Step-by-step upload and testing guide
- Project report (.docx, IEEE style)
- Presentation slides (.pptx)
