[hackerspaces] RFID access was Re: WordPress websites - what features/plugins and configurations do your spaces use?

[Arclight]

We were fortunate to get some help from a guy in the security industry when
we developed the Open Access board.  I then went to a trade show as well as
tearing down a bunch of old equipment.

The hardware in commercial alarm and access systems nothing special
technology-wise.  What makes it expensive is the limited market and need
for very high resiliance in the equipment.
We settled on an architecture that separates the "hard" tasks (Keeping the
doors, readers and sensors properly serviced and in-state) from the soft
tasks (logging, Internet connectivity).

We felt that hard tasks are best performed by a small system with a tiny
code base and real-time properties. The RasPi has GPIOs, but using them for
the real-time stuff ties us to specific hardware, and RasPi models turn
over periodically.

It also exposes us to possible issues if we manage to crash the OS.  We
incorporated a "hardened" Arduino-compatible into the board, and made it
possible to phsyically bolt a RasPi on and power/connect via serial on the
GPIO header or standard USB.

All of the inputs are protected with TVS diodes and current-limiters and
the input power has reverse polarity, noise and surge protection.

The soft tasks are likewise not so great on an Arduino.  Sure, we could use
a hardware Ethernet stack and an SD card for logging, but we're starting to
push the limits of a small device and don't get a firewall, DHCP client,
SSL, etc.

Anyway, this has been working well enough that we've sold close to 100 of
these.  You can buy one here:

https://www.wallofsheep.com

Arclight
(Shameless plugger of hackerspace businesses)
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