This Arduino and Raspberry Pi Duo Powers a Two-Factor Entry System for a Community Hackerspace

Community hackerspaces run on trust — but a little access control does not hurt. A maker named Peter published the design for his hackerspace's two-factor authentication entry system on Hackaday on March 3, and the elegant pairing of an Arduino Nano with a Raspberry Pi demonstrates exactly the kind of practical engineering that makes the maker community shine.

The Two-Board Architecture

The system splits responsibilities cleanly between two devices. The Arduino Nano handles all the physical hardware: reading input from a keypad, controlling a stepper motor that actuates the door lock, and managing LED status indicators. The Raspberry Pi runs the authentication backend, verifying QR codes and barcodes scanned at the door against a member database and cross-referencing them with PIN codes entered on the keypad.

This separation of concerns is smart engineering. The Arduino is rock-solid for real-time hardware control — reading sensors and driving motors with microsecond precision. The Raspberry Pi excels at the database queries, network connectivity, and application logic required for authentication. By giving each board the job it does best, Peter created a system that is both reliable and maintainable.

Two-Factor Security on a Budget

The two-factor approach — something you have (your membership barcode or QR code) plus something you know (your PIN) — provides meaningful security without the cost and complexity of commercial access control systems. A lost or stolen barcode is useless without the corresponding PIN. A shoulder-surfed PIN is worthless without the physical card.

The entire hardware bill of materials comes in under fifty dollars. Commercial two-factor access control systems with similar functionality typically start at several hundred dollars before monthly subscription fees. For community spaces operating on tight budgets, that cost difference matters enormously.

Built for Real-World Reliability

Peter noted that the system has been serving the hackerspace reliably for several months, handling daily use by dozens of members without issues. The stepper motor lock mechanism provides smooth, quiet operation compared to the harsh snap of solenoid-based locks. The Arduino's dedicated focus on hardware control means the lock responds instantly to a successful authentication, with no perceptible delay.

The Raspberry Pi backend logs all access events, providing the hackerspace administrators with a complete audit trail. If a member reports a lost card, their credentials can be revoked from the database immediately, and all subsequent scan attempts are logged and flagged.

Why Projects Like This Matter

Community hackerspaces are where many engineers, makers, and hobbyists develop their skills and build their networks. Practical projects like access control systems solve real problems while demonstrating how affordable embedded hardware can replace expensive commercial solutions.

The combination of Arduino and Raspberry Pi has become a standard toolkit for exactly these kinds of projects — where real-time hardware control meets application logic. Peter's entry system is a clean, well-documented example of that pattern in production use. For other hackerspaces and community workshops looking to upgrade their access control, the design provides an excellent starting point.

Sources: Hackaday, March 3, 2026