Arduino RFID (Parallax?) Project  - Advice Wanted

Hello all,

I'm new to Arduino and RFID but I'm not new to programming, microcontrollers, and breadboarding/soldering.

I'd like to purchase my first Arduino for a project where I can use an RFID keyfob to unlock a door (to start), but I'm not 100% sure on the details of how the arduino works with the RFID.

As I understand it, there's a popular 'Parallax RFID reader' that the arduino already has sample code to work with. Any idea if it would work with my existing RFID keyfob, the http://www.hidglobal.com/prod_detail.php?prod_id=22? I read that there's at least two basic models for the RFID keyfobs and they're completely incompatible with each other.

I'm hoping to get my current RFID keyfob to work (though it's not an absolute requirement, it just saves me time) but that also means that I have to be able to figure out its ID#. So I assume that I just need to hook up the arduino to an LCD and RFID reader and have the code on the arduino display what ID# it sees?

Then, assuming I want to start out basic and only check against the single RFID that I have, just add that number to a 'if true' statement that would perform the required mechanical action?

So far I'm looking at getting an Arduino, Parallax RFID reader, LCD arduino screen... and that's about it. I'm sure I have most of the 'basic electrical components' that I would need, wires/resistors/etc.

Any advice, insight, links, etc, that people can offer me would be appreciated. I'm not looking to get super complicated on this yet, I'd be happy with just ordering the basic parts that I'll need.

RFID chips have specific frequencies. Whether yours is compatible with the Parallax reader, or not, I don't know.

So I assume that I just need to hook up the arduino to an LCD and RFID reader and have the code on the arduino display what ID# it sees?

The LCD needs to display the code only for debugging purposes. Once you know that you can read the tag, and determine that it is the correct tag (or one of the correct tags), you no longer need the LCD.

just add that number to a 'if true' statement that would perform the required mechanical action?

Yep.

I'd like to purchase my first Arduino for a project where I can use an RFID keyfob to unlock a door

So far I'm looking at getting an Arduino, Parallax RFID reader, LCD arduino screen... and that's about it.

Probably need some sort of electrically controllable door lock, too.

If you are looking at RFID readers, I think I can save you any time you might spend on the one from Phidgets... it interfaces to its host via USB, which I think you want to avoid, if the host is an Arduino. I like what I know about Phidgets and their products... but in this case, there's a mis-match(?) between needs and features.

Know also: many of the fancier Phidgets devices need a library which isn't easy to "look" into.

I read that there's at least two basic models for the RFID keyfobs and they're completely incompatible with each other.

A bit of out of date reading there are four basic frequencies and three basic types. Even within a frequency and basic type the variates of RFID tokens are incomparable. Without knowing what type of RFID tag you have it is impossible to know what readers will suite you.

Any idea how I could go about figuring out what type/sub-type of fob I have?

All I have was the link (which has a datasheet pdf) which said it was a 125Khz fob. Does that at least narrow it down?

That fob (apologias for not following the link earlier) is known as an EM type tag. It is one of the easiest to read. Look for a reader that does this type of tags.

I used three in this project:- http://www.thebox.myzen.co.uk/Hardware/Crazy_People.html But then I didn't actually pay for them.

Fobs are cheap. Readers are expensive. Even if it means "throwing away" your fob, some research to find the best RFID technology for your needs, then buying a reader THEN buying a fob might be the "way to go"?

I mention this not to be snide, but in hopes that many will read this thread, as we so often see people in comparable quandries, with comparable realities, not just with RFID projects.

Some radio shacks still have the RFID readers from parrallax for $10 or so if you can find one that has not sold out of them yet ( they discontinued them )

Thanks everyone for your input and information.

'Throwing away' my current fob (or at least not using it) has always been an option I was considering. I didn't pick it, it's used for access elsewhere, I just thought it would make sense for me to read/code it for my project instead of having more than one fob to carry. (Assuming it wasn't too expensive.)

It sounds like if I wanted to spend ~$80 on a reader, I could get one of these: http://www.prosecuritys.com/bosch-ardayk12.html and try and get it to work with my current fob.

But it also sounds like if I wanted to buy a ~$50 kit which would include a Parallax reader + keys that I know would work with it, I should go with http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&pa=2007169&productId=2007169&keyCode=WSF&CID=GMC

As I said before, I think there's already sample code for the Parallax reader working with the arduino, and some projects that I could mimic, but there appear to be different models of the Parallax reader, does anyone have any advice on the differences?

seeedstudio.com has several RFID readers for under $20, including 125kHz ones. I got one of them to play with. There is code posted in the forum for using them to read and understand the RFID tags.

Any thoughts on UART vs Weigand? They're just the output protocol of the reader, correct?

Yes sort of. Wiegand is two outputs where as a UART is serial. I think you are better off with a Wiegand as you don't have the bother of a second serial port on an arduino. You can just connect the outputs to interrupt lines like I did on the project I posted before.

There's an instruction on Instructable on how to do this... http://www.instructables.com/id/Arduino-RFID-Door-Lock/

He didn't use the Parallax but instead a Sparkfun ID-20, which you can use the ID-12 as well since Sparkfun is sold out of the ID-20.

If you insist on using the Parallax... http://www.gumbolabs.org/2009/10/17/parallax-rfid-reader-arduino/

I will be doing the same project, using most of the parts from the instructable, but will be using the parallax. :-)