Arduino RFID tag detection

I am working on a design project and the topic is a supervision system. I haven't worked with Arduino before, so I'm looking for advices from experienced users.

The idea is that a location will have a terminal/system that will read RFID tags. When someone walks in (they are carrying a RFID tag), the terminal/system detects it and posts to a database online. When the person leaves and the terminal/system can't detect the RFID tag anymore, the terminal/system posts to a database online as well. Perhaps if the location is too big, the terminal will be attached to a door and the database will be updated when the RFID tag is read by the terminal/system, signifying that the person as entered or left.

I need some direction from you guys. What Arduino board should I be looking at to read the RFID? Also, what kind of RFID tag (passive or active, preferably passive) should I be looking at if I want the read distance to be 2-3 metres? Would the reading distance be based on the actual reader? If 2-3 metres is not a good match for a RFID solution, what might be?

There is also something a little more precise that I have to take into account. Is there a way to detect which direction the RFID detect is coming from? Say I walk in from left to right of the sensor - is there a way of logging any coordination related data?

I realize I'm asking a lot of question, but I'm new to the world of Arduino. I really appreciate the help.

Lemme say this first: I haven't done RFID myself although I've researched it quite a bit so I'll do my best

What Arduino board should I be looking at to read the RFID
I'd say just the UNO is the best choice. Its the most popular board.

what kind of RFID tag (passive or active, preferably passive) should I be looking at if I want the read distance to be 2-3 metres?
I don't believe that there are many modules that can read a 2m-3m distance that are affordable. And I think that is more of a reflection on the reader rather than the tag.

Would the reading distance be based on the actual reader?
Yes

Is there a way to detect which direction the RFID detect is coming from?
I don't believe so. The tag just emits a simple id signal. The reader has no perception of orientation so I don't think this is possible.

What might be a good choice of tag/reader for 1-2 metres? Is there anything else that might be better than RFID in that case?

The tag needs to be powered. There are several long range readers Avaliable but they are all in the $400 region. If you make your own powered tag it will be bulky.

Hmmmm 1m is still pretty far for affordable RFID readers. I haven't found any that are around just a meter either. there are many that are around $500 but those are for about 450 feet ranges.

You could try RF frequencies.

If you want to go with RFID, you might be able to squeeze some range out of it, check out this article.

It seems that for longer ranges, I have to use UHF readers and tags. Would I be able to use something like this with Arduiono http://www.ebay.com/itm/Long-Range-UHF-RFID-reader-USB-ISO18000-6C-EPC-G2-/110934066028?pt=LH_DefaultDomain_0&hash=item19d42f836c

Do you know of any UHF readers and tags with Arduino to use?

As RFID readers output serial or Wiegand then you can use any reader with an arduino.

OK, after researching a lot, this is what I have found to be the best match.

Reader: http://www.cutedigi.com/sensor/id/cottonwood-long-range-uhf-rfid-reader-uart-iso18000-6c-epc-g2.html
Antenna: http://www.cutedigi.com/sensor/id/5dbi-pcb-uhf-rfid-902-928m-antenna-5cm-x-5cm.html

Can anyone point me towards how to hook this up to an Arduino Uno board?

Also, is it a better idea to somehow set up a transmitter and receiver in a straight line to read a passive RFID tag? I don't know if this can be done, but it's just something that came to me as I was thinking about antitheft systems.

Somebody may be able to still help you better but read this.

That module communicates through UART

Well just one click away from the link you posted is an arduino example of how to hook them up.
http://linksprite.com/article/shownews.php?lang=en&id=64

Hello over9k,

Do you have any updates on this endeavour? I too am looking for a similar hardware setup and would appreciate if you could share your findings, recommendations, and conclusions. I have sent you a PM with some more detailed questions as well.

Any help would be greatly appreciated!