Arduino TOTP Authentication Keypad Kit - Rolling PIN Every 30s
Build a Multi-Layer Authentication Keypad with Time-Based Rolling PIN Using Arduino
Every part needed, pre-tested for compatibility, with an AI build companion trained on this exact project. Shipped from Bengaluru in 3-5 days.
Static PIN keypads are vulnerable to shoulder surfing and brute force. This kit generates a new time-based PIN every 30 seconds-akin to TOTP used by Google Authenticator-by seeding a custom algorithm with a DS3231 real-time clock on an Arduino Uno. The result: a surveillance-grade access system where even a captured code is useless seconds later. Ideal for hostel rooms, lab lockers, or engineering capstone projects.
What You'll Build
You'll assemble a keypad station with an OLED display showing a rolling 6-digit PIN, computed from RTC time and an EEPROM-stored secret. Entering the correct current PIN on the 4x4 keypad activates a 5V relay to unlock a door or disarm a system. The build includes hardware debouncing, flyback diode protection, and decoupling capacitors-reliable enough for real-world deployment.
What You'll Learn
- Implement a TOTP algorithm on an 8-bit microcontroller using modular arithmetic and time-synchronized HMAC-style hashing
- Interface a DS3231 RTC over I2C for drift-free timekeeping and battery-backed seed retention
- Design a multi-layer input stage with keypad matrix scanning, hardware debouncing, and EMI filtering
- Integrate a 5V relay with flyback diode and transient voltage suppression for safe high-current switching
Kit Contents
| Component | Quantity |
|---|---|
| Arduino Uno R3 | 1 |
| DS3231 RTC module | 1 |
| 4x4 Matrix Keypad | 1 |
| 5V Relay Module | 1 |
| 0.96-inch OLED display (I2C) | 1 |
| 1N4007 Diode | 5 |
| 10k? Resistor | 5 |
| 100nF Ceramic Capacitor | 10 |
| PCB Prototype Board | 2 |
| 9V Battery Snap | 1 |
| Soldering Iron (25W) | 1 |
| Solder Wire (50g) | 1 |
Why Buy This Kit Instead of Sourcing Parts Separately
| Factor | Sourcing Separately | Compoden Kit |
|---|---|---|
| Compatibility checks | You verify every part | Pre-tested as a system |
| Build support | Forums and scattered tutorials | AI companion trained on this exact project |
| Time to first working build | Days of debugging | Hours, with step-by-step guidance |
| Shipping coordination | Multiple sellers, multiple delays | One shipment from Bengaluru in 3-5 days |
Who This Kit Is For
Designed for B.Tech ECE and EEE students, Smart India Hackathon teams, and IIT/NIT final-year projects requiring advanced embedded security. If you've already built a basic keypad lock, this kit bridges the gap to time-based authentication systems.
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.
What if I get stuck during the build?
Scan the QR code for the AI companion trained on this kit; it can troubleshoot exactly your wiring and code. WhatsApp human backup is also available.
Do I need prior experience with cryptography?
No-the TOTP code is provided, with step-by-step explanations of how time-based hashing works on an 8-bit MCU.
Can this system operate without a constant USB connection?
Yes, the DS3231 has a coin cell for timekeeping, and the 9V battery snap powers everything. The rolling PIN works offline.
Is this kit suitable for a college mini-project or hackathon demo?
Definitely. It's a full access control system. Many students have used similar projects for evaluations and hackathons successfully.
Time-based rolling PIN that changes every 30 seconds like TOTP. Code computed from RTC seed on Arduino.
What's in this kit
Choose your assembly option:
- Soldering Kit - 25W soldering iron, 60/40 solder wire, flux, and small perfboard for permanent assembly.
- Breadboard Combo - 800-point full-size breadboard with 65-piece jumper wire pack for solderless prototyping.
Shipping Information
- Prepaid Orders: ₹75 for orders up to ₹999, FREE shipping above ₹999
- COD Orders: ₹125 shipping + ₹50 COD fee = ₹175 total
- Delivery Timeline: Dispatch in 1-2 days, delivery in 2-7 days depending on location
Returns & Warranty
- 7-Day Return: Manufacturing defects only (approval required)
- Warranty: 7 days from delivery
- Non-Returnable: Batteries, consumables, cut wires, clearance items