Introduction
Radio Frequency Identification (RFID) is one of the automatic identification or auto ID systems like bar codes, smart cards, voice recognition etc., used to help machines identify objects. This technology is often coupled with automatic data capture systems to identify objects and capture information and transfer them into computer without data entry. Naturally, the aim of these systems is to increase efficiency and reduce data entry. RFID has been around for long time with many literature published on it. This article is just a little extract of those, and hopes to give a high level overview of the RFID technology, its characteristics, its applications, and its relevance to Windows CE world.
What is Radio Frequency Identification?
It is a generic term for technologies that use radio waves to automatically identify people or objects.
Components of a RFID System:
- A transponder or tag consisting of a microchip and a miniature antenna. Information to be processed is written in microchip. The antenna is used to emit/receive radio signals.
- An interrogator or reader consisting of a transceiver, decoder, and antenna. The transceiver is used to receive radio signals which is decoded to byte stream by decoder. The antenna is used to emit/receive radio signals.
How does a RFID system work?
- The object to be tracked is affixed with a RFID tag or transponder.
- The reader, kept at some position like entrance or door frame through which objects to be tracked pass, emits radio signals.
- When the object containing RFID tag comes within the range of radio signals emitted by the reader, the tag is activated and it starts sending the information stored in it in the form of radio signals.
- The reader captures the radio signals, decodes it to a byte stream, and sends the information for further processing to the host system connected to it.
More about RFID tags:
A RFID tag can store up to 2000 bits of information. They come in a variety of shapes and sizes. For example, animal tracking tags inserted beneath the skin are small as pencil. Tags used to track trees or wooden items are screw shaped. Credit card shaped tags are used for security applications. A RFID tag can be further categorized as Active or Passive. Active tags are powered by internal battery and information written to it can be modified. Passive tags operate without external power and obtain operating power from the radio waves generated by the reader. Passive tags are lighter and less expensive than Active tags. Their lifetime is virtually unlimited. But they have shorter read ranges and require a high powered reader.
Frequencies:
Based on the type of domain or application targeted, RFID systems are generally distinguished to three frequency ranges - Low, Intermediate and High. The following table summarizes these three frequency ranges, along with the typical system characteristics and examples of major areas of application:
| Frequency Band |
Characteristics |
Typical Applications |
Low
100-500 KHz |
Short to medium read range, inexpensive, low reading speed |
Access control, Animal identification, Inventory control, Car Immobilizer |
Intermediate
10-15 MHz |
Short to medium read range, potentially inexpensive, medium reading speed |
Access controls, Smart cards |
High
850-950 MHz
2.4-5.8 GHz |
Long read range, high reading speed, line of sight required, expensive |
Railroad car monitoring, Toll collection systems |
Applications of RFID Systems:
Potential applications for RFID may be identified in virtually every section of industry, commerce, and services where data is to be collected. Principal areas of applications for RFID that can be currently identified include:
- Transportation and logistics
- Manufacturing and processing
- Security
A range of miscellaneous applications may also be distinguished, some of which are steadily growing in terms of numbers. They include:
- Animal tagging
- Waste management
- Time and attendance
- Postal tracking
- Airline baggage reconciliation
- Road toll management
Some of the prominent specific applications include:
- Electronic article surveillance - clothing retail outlets being typical.
- Protection of valuable equipments against theft, unauthorized removal, or asset management.
- Controlled access to vehicles, parking areas, and fuel facilities - depot facilities being typical.
- Automated toll collection for roads and bridges - since the 1980s, Electronic Road-Pricing (ERP) systems have been used in Hong Kong.
- Controlled access of personnel to secure or hazardous locations.
- Time and attendance - to replace conventional "slot card" time keeping systems.
- Animal husbandry - for identification in support of individualized feeding programmes.
- Automatic identification of tools in numerically controlled machines - to facilitate conditional monitoring of tools, for use in managing tool usage, and minimizing waste due to excessive machine tool wear.
- Identification of product variants and process control in flexible manufacturing systems.
- Sport time recording.
- Electronic monitoring of offenders at home.
- Vehicle anti-theft systems and car immobilizers.
Drawbacks of RFID:
For all the applications of RFID, no standardization has been done as of now. All major RFID vendors offer proprietary systems not compatible with each other. Another drawback is the cost. RFID Readers and tags are fairly expensive. There is also the collision of signal from one reader with signal of another reader which is called Reader collision. Like Reader collision, there can also be Tag collision in which more than one tag reflects back the signal of the reader at the same time, confusing the reader.
Windows CE and RFID:
Many third party vendors like Socket Communications, Symbol Technologies are planning in a big way to provide support and solutions for RFID on Windows CE devices. In fact, Socket Communications has announced a pair of kits intended to assist developers in integration of RFID technology to mobile RFID applications on Pocket PC. For more details, please refer this link. Symbol Technologies is the active member of EPCglobal, a non profit organization entrusted to derive a global standard for RFID solutions. So in the coming future, we can see many developer kits and products on RFID being released by these vendors. Everything depends on how fast the standardization of RFID is done.
Conclusion:
In the RFID standardization front, the good news is that International Organization for Standardization (ISO) is working on standards for tracking goods in the supply chain. EPCglobal, a joint venture setup to commercialize Electronic Product Code technologies, has its own standards process, which was used to create bar code standards. EPCglobal intends to submit EPC protocols to ISO so that they can become international standards. So let's keep our fingers crossed :).
