card reader, retrieving memory without using MP.

Microprocessors can be cheap. In 1000 off quantities you can buy them with flash memory for that ID i.e. using a microprocessor (clearly avoidable). I ain't no

Security is not that big an issue here. This card access facility is being installed just to have an idea of 'who came in today?' an end of the day analysis. Also where this facility is being provided it seems unlikely for anybody to know anything about electronics so no security (tho there's isn't much to worry about anyway) breaches expected that way. Mr. Watters could you give me any references to articles where I may find info about creating cards using MPs and ROMs.

Thanx

Stuart

Not entirely clear on what you want to do but it seems to me that a "gold card" is what you want, that's a PIC16F84 and 24C16 in a wafer, they are about £2 each in 1s, very cheap in 50s or so. Very easy to programme and read using a PC and about $20 wortrh of hardware that you can buy or make.

If you search for gold wafer on google or browse a few satellite TV sites you will find them. If you want more security or more capability then there are Atmel micro based cards for not a lot more money.

Even from scratch without a PC the technical requirements in terms of clock and serial transfer are really simple.

There is loads of stuff on the web. Try this page for some S/W.

I've no experience with these programs but these look like they might be of interest....

"Smartclock, A smartcard clocking in system. Control employee arival and departure times." "smartlock, program to control unlocking of doors etc.

Going slightly off topic...

Some time ago the Olivetti Research lab in Cambridge England (now owned by AT&T) developed an IR Active Badge system that also did something like you propose. I'm not sure if it's available commercially and the badges wern't cheap back in the early 1990's. This system allowed you to find out where people were in a large building for example.

Why would people wear an active badge....

there

clock

It's not clear to me whether you have some existing cards in mind which you want to be able to read, or whenther you're free to choose any card+reader technology you like. If the latter, have you thought about a simple barcode or magnetic stripe? As the user swipes a card past the reader, the barcode or stripe will naturally produce a serial bitstream. The difficulty with this approach is timing: people will swipe their cards at different rates, and the rate won't be constant (they might start slow and speed up, for example). There are various way to deal with that, such as having a synchronization preamble, or a "self-clocking" data format, or just having two stripes on the card (one for clock and one for data). You usually end up having to have a microcontroller in the reader to handle the timing.

Existing "chip cards" work like this. You could get similar functionality by putting a cheap 2-wire EEPROM on the card. Actually, I suspect that you can buy unprogrammed chipcards pretty cheaply.

But if you are going to make, (say) 5 readers and 100 cards, then it's worth making the reader more complicated/expensive if you can make the card cheaper.