Good question. You know what it's like when you're familiar with something - you just naively expect everyone else to be.
Sorry about that - had my techie head on for a while there, but I'm fine now.
OK Class - here's a stripped down, de-technicalised view of RFID for you to get a better idea of just what I'm twittering on about.
RFID = Radio Frequency Identification
First developed in WW II for identifying friendly aircraft, it became popular as a business technology in the late 80's.
RFID kit is made up of several key areas
Tag, or transponder
This is the element that actually contains the data, and these can be either passive or active. Passive tags have no battery, but wake up when an RFID reader is placed near them and transmit the stored data to the reader. Because of this,passive tags have an almost unlimited operational lifetime. Active tags ( hey, you're ahead of me ) have their own battery and are "always on". The tags contain an antenna to boost the signal. Tags are available in many formats including labels, ceramic mounted ( for vehicles etc ), glass mounted ( for animals etc) and new technologies are working on other production methods for tag development and manufacture.
Reader
Guess what this does? Yup, it reads the tag and then analyses the data. Readers can be static or embedded into handheld devices.
Middleware
This is the software that translates the data on the tag into front end applications where that data is analysed. RFID can produce massive amounts of data so middleware is crucial.
Antenna
As I said, tags have an antenna in them, but depending on frequency, tag type etc the range can be very limited - approx 7cms for one type. By using strategically placed antennas it is possible to strengthen transmissions. Good antenna design and implementation is pivotal to successful RFID deployment.
Host PC
Well, the data has to go somewhere, doesn't it?
Frequencies
Depending on the application, there are several frequencies that tags work on. It all has to do with the product the tags are affixed to, the environment they're used in and the type of data capture the user is after. Each has their own benefits and drawbacks.
Who not stick with barcodes?
Ahh, the eternal question. I've said before some people want RFID because it's RFID. There's not always sound reason behind the implementation. Barcodes are magnificent. They're ubiquitous, they're safe, they're non-threatening. And they're amazingly efficient. But they can be compromised with weather or environment such as oil or grease blocking the scan, only one can be scanned at a time, and they need to be in the line of sight of the scanner. Who likes hauling their case of beer/wine/pop up into the checkout conveyor?
RFID doesn't have these problems. Yes, depending on environment RFID can be compromised - metal and liquids never make RFID happy particularly but again these can be worked around. And it's an invisible read, if you like. Depending on reader placement or deployment, the tag can be at any point in the contained area and it'll be read. Multiple tags will at once, actually. So you get a much faster and generally very efficient read rate from tags.
Now, I'm sure some of you will want to pick me up on some points - but this is a de-technicalised view of RFID, a taster. It's not RFID 101. It's not written to make you an expert on RFID, but it's here to give you the slightest idea about RFID, its capabilities and the most basic requirements. If you want to talk techie, I'm happy to.But sometimes, just sometimes, people don't want to know the intricacies of a technology. This is one of those times.