Architecture

Main components

Server

centralized "manager" of the rest of the system:

• database storing info about who can open which door (for details see Data Model)
• compiles the access rules into something the devices can use, pushes these to the devices
• auxiliary functions: firmware updates, current time ("NTP")
• stores logs from devices

Controller

given an ISIC number, decides whether to open the door

• controls a single door
• communicates with the server (gets access rules, sends logs) and one or two readers
• can make decisions offline -- when the server is inaccessible but the controller is still powered, its door functions

Reader

the ISIC reader ("the box")

• user-visible -- provides the user interface
• reports to its controller when there is an ISIC
• more (probably one or two) of them can be connected to one controller (e.g. inside and outside)