[ILUG] Re: Swipe Card System

[Michael Watterson]

Tony Groves wrote:
> On Tue, 2007-07-31 at 09:06 +0100, Robert Fitzsimons wrote:
>
>   
>> I would suggest you start out by looking at the gumstix
>> (http://www.gumstix.org/) for the host computer.
>>     
>
> Interesting, I'll look into that.
>
>   
>> But it could cost hundreds maybe a thousand euro to setup the system,
>> could this be a case of big expensive lock on a crap bike?
>>     
>
> It's an important building and it has to be secured and made available
> to authorised people. We don't want the whole world wandering in and out
> at will. Sure it'll cost a bit, but there are 250 people to share the
> cost.
>
>   
>> My experience on this topic is mostly with experimenting with RFID cards
>> and RFID reader.  I've got a couple of readers the open source OpenPCD
>> (http://www.openpcd.org/) and two CardMan devices bought from
>> (http://www.cryptoshop.com/).
>>     
>
> Am I right in thinking that all RFID cards for a particular reader have
> to be identical? That would be no use. Each card has to be unique to the
> individual holder, for the purposes of authorisation checking and usage
> logging.
>
>   
No. Each RFID can store more unique information than a barcode. They are
nearly as easy to read as a barcode and can be read at a distance. Fine
for stuff in a shop or warehouse, or baggage routing at an airport, but
useless to secure a  building. Even an easily photo-copied cheap barcode
is more secure because the owner would be able to secure it. RFID can be
copied as owner walks past a car.

Magstripe, or chip card or similar.   I'm  sure there are people selling
RFID door locks but it will end in tears.

For 250 people the magstripe  would  do.  Cheap  cards  and  unlike RFID
the card  has to be physically  obtained  to copy it. Available  off
the  shelf.   PC used  to program cards and  semi  dumb   embedded
controller to  operate lock.  A  card can be  disabled on a  the lock
without PC.  You  program a  master  card  and swipe the lock. This then
cancels the unwanted card. Regulars can have a plastic card. Some
systems can have a disposable (maybe 20c) cardboard  mag card  too  that
works  a pre programmed number of times.

Chip or "Chip and Pin" the reader is much cheaper but the "blank cards"
are 10 to 20 times the price.

-- 
Mike