[hackerspaces] Open Access Control for Hacker Spaces v1.0

john arclight arclight at gmail.com
Fri Apr 9 21:58:19 CEST 2010

Hi all,

We've got a preliminary hardware design together finally, along with
the code.  Check out the schematic and download links for everything


This system uses the Arduino Duemilanova board and so far has been
breadboard tested to support:

-DS1307 Real-time clock with battery backup
-(2) Wiegand26 reader inputs (optoisolated)
-(4) Alarm zone monitor ports using Analog0..3 (optoisolated)
-(4) Relay outputs, rated to 10A/220VAC
-Spare pins 10..13 to enable Ethernet shield use
-Built in 12V unregulated, 5V regulated, 12V regulated supplies for
alarm sensors, door hardware
-Built in UPS (smart charger in next design)
-Separate fuse protection for everything

So this will basically allow 2 separate Wiegand26 door readers, 4
independent relay outputs for unlocking doors or alarm sirens, 4
inputs for alarm/other sensors, easy upgrade to Ethernet logging.
(It's currently doing Syslog format via USB serial.) It has a built-in
UPS backup, much like a commercial alarm system and it allows multiple
power buses for motion detectors, fire sensors, etc that are separate
form the logic bus. I also put an EMF kick-back diode in for the door
hardware bus (unregulated 12V).
 I would appreciate any feedback in terms of:

1. What additional features would be nice?
2. Any obvious design flaws.



More information about the Discuss mailing list