[ILUG] Re: Swipe Card System

[Tony Groves]

Tony Groves wrote:
> 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.
> 

Robert Fitzsimons wrote:

> Each card has an unique ID number with some transponders (cards)
> having up to a 128-bit unique number.  Also some transponders have
> built in EEPROM which can contain extra application specific data.


Philip Trickett wrote:

> Why don't you have a look at these:
> http://www.maxim-ic.com/products/ibutton/
> Not contactless, but the form factor is a lot easier to carry around.
> They are tough as well, I ran mine over with the car, it still
> works...


Michael Watterson wrote:
> 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
> thatworks  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.


Sorry for the delay in responding, gents. Long weekend and all that ...

RFID cards sound OK. All I need to do is to record the serial number
each time a card is issued to a user. It seems that security is weaker
than other card types, but we're not dealing with Fort Knox or computer
hackers here.

The final choice of card technology will, I suppose, be down to finding
a suitable tough reader/lock, and a reasonable-cost supplier of
pre-printed cards. Which would seem to boil down to magnetic strip or
RFID.

The access control and logging has already been discussed and I have a
choice of an embedded controller or an old PC. Probably the handiest
thing would be to start off with an old PC running Linux, and maybe
migrate to the unfamiliar technology of an embedded controller at a
later stage.

OK, I've loads of feedback to go on now and plenty of links to research,
so I'll start figuring out suppliers and costs and see what's the best I
can come up with. Thanks for your time.

Tony.