This door controller software was originally developed for the
the Hackforge hackerspace in Windsor, ON, Canada.  It is a work in 
progress and will eventually (hopefully) be able to handle many types 
of hardware and software interfaces.


=== Database ===

The software currently uses a small SQL database with 2 tables for storing 
users and RFID cards.  It uses SQLAlchemy and, if necessary, will 
auto-create a SQLite database w/ the proper schema on startup.

By default it uses SQLite but it also supports MySQL.  For now, database 
tables must be populated by hand.  


=== Hardware ===

This software was written to run on a Raspberry Pi v2.  

By default it assumes you have the following hardware hooked up
to the corresponding RPi pins:

    * pin 10 --> RDM6300 RFID reader TX output 
    * pin 24 --> red LED 
    * pin 23 --> green LED
    * pin 27 --> piezo buzzer 
    * pin 25 --> a relay that controls a door magnet or door strike
    * pin 17 --> a button to re-lock the door


=== Control Logic ===

When the door controller starts up, it defaults the door relay to closed 
(i.e. locked), the red light on, and the green light off.  

The main loop waits for an RFID tag.  Once it gets a tag, it checks
the database to see if the card is valid.  

If the card is valid, the green light comes on for a couple seconds, 
the buzzer sounds and the door unlocks.  Once the door is unlocked, it 
sits and waits for the lock button to be pressed.  After the lock button 
is pressed, it waits 5 seconds then re-locks the door.  

If the card is bad, the red light flashes 3 times along w/ 3 beeps from 
the buzzer and the door stays locked.


Shawn Wilson
Oct 2015