Smart Padlock with PIN — Arduino Security Kit That Combines a Keypad-Controlled Servo Lock and Intruder Alarm

Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.

Ever wanted a padlock that only you can open — not with a key but with a secret PIN? This kit lets you build a tabletop smart padlock that uses a 4x4 matrix keypad for code entry. When the correct 4-digit PIN is typed in, a servo motor lifts the locking shackle and a green LED confirms success. Enter the wrong code three times, and a loud buzzer sounds while a red LED flashes to signal a lockout, just like commercial security systems. Ideal for securing a diary box, a project showcase, or mastering access control concepts in one afternoon.

What You'll Build

A fully functional embedded security device. After programming the Arduino Uno, you’ll have a model padlock where the servo-driven arm acts as the shackle. The keypad accepts a default PIN; entering it correctly moves the servo to the “unlock” position for a set time. Each incorrect guess increments an internal counter — after the third consecutive wrong try, the system disables all input and triggers the active buzzer and red LED for a configurable lockout period. You’ll see exactly how hardware and software work together to create a real access control system.

What You'll Learn

• Interfacing a 4x4 matrix keypad and decoding multi-key presses
• Controlling a servo motor for precise mechanical actuation
• Writing state logic for PIN verification, attempt counting, and alarm activation
• Connecting active buzzers and LEDs for real-time audio-visual feedback

Kit Contents

Why Buy This Kit Instead of Sourcing Parts Separately

Who This Kit Is For

CBSE Class 11-12 students designing security prototypes for science exhibitions or ATL Tinkering Labs. First-year B.Tech ECE/EEE learners seeking a hands-on embedded systems mini-project. Smart India Hackathon participants building rapid physical access control demos. Anyone curious about how PIN-based locks actually work — with a kit ready to be tested right out of the box.

Built and Backed by Compoden

Every Compoden kit ships with an AI build companion trained on this exact project — accessible via a QR code on the box, with WhatsApp and email backup. We've spent 10 years building projects for makers, schools, and institutions across India. If a part fails because of a manufacturing defect, replace it free within 7 days.