May 25, 2014
Not everyone knows this, but the access control system at Hackforge is rather unique. Instead of a closed, commercial system we built our own.
Members Randy and Terry are responsible for the latest version of the system. Randy is an expert in python programming, and Terry is an expert in electronics. Together they built a system around a Raspberry Pi. Running Linux, the RFID card reader and a relay control board are connected to the GPIO pins on the Pi.
When it boots, it runs a python script that waits for card numbers sent via serial to the Pi. When it receives a number, it checks the number against an SQL database on the SD card. If it finds the number, one of the GPIO pins is pulled high. This signal tells the relay board in the upper left to turn on its relay. The relay then disconnects power from the maglock on the door, and the person who scanned their card is able to enter.
The Pi rests in a 3D printed case, made using member Amber’s LulzBot. Thanks for the work everyone, Hackforge wouldn’t be the awesome place it is without you!