RFID-Radio-frequency identification(RFID Technology Description,RFID and .Net Integration )

Radio-frequency identification (RFID) :is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders.

• Main Components: RFID reader, RFID tag
• RFID tag:
• is an object that can be applied to or incorporated into a product, animal, or person for the purpose of identification and tracking using radio waves. Some tags can be read from several meters away and beyond the line of sight of the reader.
• Most RFID tags contain at least two parts. One is an integrated circuit for storing and processing information, modulating and demodulating a radio-frequency (RF) signal, and other specialized functions. The second is an antenna for receiving and transmitting the signal.
• Types of RFID tags: active RFID tags, which contain a battery, passive RFID tags, which have no battery.
• RFID Reader:
• A device used to communicate with RFID tags.
• It has one or more antennas, which emit radio waves and receive signals back from the tag.
• It is also sometimes called an interrogator because it "interrogates" the tag.
• It is An electronic device used for communication between RFID tags and a host computer system.
• A reader generally consists of an RF transmitter and receiver and an antenna for communicating with tags. A digital interface enables the reader to communicate with the host computer system.
• Reading distance :
  The distance between the antenna of a reader and a tag over which the read function can be effectively performed. This distance is influenced by the orientation and angle of the tag with respect to the antenna, and possibly by environmental conditions.

RFID-Real Time Applications:

• Supply chain automation - the key early driver for developments and implementation of the technology
• Asset tracking - tracking of assets in offices, labs, warehouses, pallets and containers in the supply chain, books in libraries Medical applications - linking a patient with key drugs, personnel giving the drugs, biometric measurements
• People tracking - security tracking for entrance management or security, contact management at events, baby tags in hospitals to manage access to post-natal wards
• Manufacturing - tracking of parts during manufacture, tracking of assembled items Retail - tracking store trolleys in supermarkets, active shelves
• Warehouses - Real-time inventory by automated registration of items in a warehouse or store-room
• Livestock - implanted RFID tags in animals for tracking and linking the animal to food, location. Applicable to farming as well as exotic breeds in zoos
• Timing - sports event timing to track athletes as they start a race and pass the finish line

How does an RFID system work:

• An RFID system consists of a tag made up of a microchip with an antenna, and an interrogator or reader with an antenna.
• The reader sends out electromagnetic waves. The tag antenna is tuned to receive these waves.
• A passive RFID tag draws power from the field created by the reader and uses it to power the microchip's circuits.
• The chip then modulates the waves that the tag sends back to the reader, which converts the new waves into digital data.

Which frequency is right for your application?

• Different frequencies have different characteristics that make them more useful for different applications.
• For instance, low-frequency tags use less power and are better able to penetrate non-metallic substances. They are ideal for scanning objects with high-water content, such as fruit, but their read range is limited to less than a foot (0.33 meter).
• High-frequency tags work better on objects made of metal and can work around goods with high water content. They have a maximum read range of about three feet (1 meter).
• UHF frequencies typically offer better range and can transfer data faster than low- and high-frequencies. But they use more power and are less likely to pass through materials. And because they tend to be more "directed," they require a clear path between the tag and reader.
• UHF tags might be better for scanning boxes of goods as they pass through a dock door into a warehouse. It is best to work with a knowledgeable consultant, integrator or vendor that can help you choose the right frequency for your application.

Standardized Frequency Bands:

• low frequency (LF) : 125 to 134 kHz;
• high frequency (HF) : 13.56 MHz;
• ultrahigh frequency (UHF) : 860 to 960 MHz

RFID and .Net Integration:there are few API's which helps us to interact with RFID readers ,so that you can control the RFID devices functionality via .Net applications through these API's.Here i am using Phidgets application programming interface (API).

• Phidgets :Phidgets are a set of "plug and play" building blocks for low cost USB sensing and control from your PC. All the USB complexity is taken care of by these API's. Applications can be developed quickly in .NET, Visual Basic, VBA (Microsoft Access and Excel), LabView, Java, Delphi, C, C++ and Python.Via (http://www.phidgets.com/)
• Implementation :create new windows application.Install the Phidget API Dll in your system.Reference the dll in C# application.
• NameSpaces:using Phidgets;using Phidgets.Events;
• RFID : This object will be assigned to the RFID reader so that we can pull information from it.
• To use the RFID reader, you will need to create an RFID object and then open the reader. You also will want to create a few event handlers to control actions that occur from the reader
• The first thing that happens is that an RFID object is created called rfid1. This will be used to attach to the RFID hardware. Before opening the hardware for use, event handlers are created for attaching to the RFID reader (myRFID_Attach), detaching from the reader (myRFID_Detach), having a tag put near the reader (myRFID_Tag), and having a tag move out of the reader's range (myRFID_TagLost). After adding these handlers to the rfid1 object, the open method is called to begin using the RFID object
• To use the RFID reader, in addition to being connected to your machine, it also has to be turned on
• Turning on the reader is simply setting the Antenna property of your RFID object to true
• myRFID.Antenna =true
• The next important thing is to read a tag. This is done in the myRFID_Tag event handler that was added to the rfid1 object in the Form_Load event

Sample Code:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing; using System.Text;

using System.Windows.Forms; using Phidgets; // Import Name Spaces

using Phidgets.Events;

namespace RFIDTest

{

public partial class MyRFIDReader : Form

{

RFID myRFID; // Declare RFID Object

string lastTag; // Tag that just read

public RFIDReader()

{

InitializeComponent();

lastTag = "";

}

private void Form1_Load(object sender, EventArgs e)

{

myRFID= new RFID();

myRFID.Attach += new AttachEventHandler(myRFID_Attach);

myRFID.Detach += new DetachEventHandler(myRFID_Detach);

myRFID.RFIDTag += new TagEventHandler(myRFID_Tag);

myRFID.RFIDTagLost += new TagEventHandler(myRFID_TagLost);

myRFID.open();

}
// Reading Tag

private void myRFID_Tag(object sender, TagEventArgs e)

{

lastTag= e.Tag;

myRFID.LED = true; // on light

}
// When tags over

void myRFID_TagLost(object sender, TagEventArgs e)

{

txtTag.Text =

myRFID.LED = false;

}
// Detaching Reader

private void myRFID_Detach(object sender, DetachEventArgs e)

{

lblAttach.Text = "Detached";

}
// Attaching Reader to application

Private void myRFID_Attach(object sender, AttachEventArgs e)

{

Phidgets.RFID phidTag = (Phidgets.RFID)sender;

lblAttach.Text = phidTag.Name;

lblSeriaNumberl.Text = phidTag.SerialNumber;

lblVersionNumber.Text = phidTag.Version;

}
// Turn On The Reader

private void antennaButton_Click ( object sender, EventArgs e)

{

myRFID.Antenna = True;

}

}

}

Is RFID better than using bar codes:The two are different technologies and have different applications, which sometimes overlap. The big difference between the two is bar codes are line-of-sight technology. That is, a scanner has to "see" the bar code to read it, which means people usually have to orient the bar code toward a scanner for it to be read. Radio frequency identification, by contrast, doesn't require line of sight. RFID tags can be read as long as they are within range of a reader. Bar codes have other shortcomings as well. If a label is ripped or soiled or has fallen off, there is no way to scan the item, and standard bar codes identify only the manufacturer and product, not the unique item. The bar code on one milk carton is the same as every other, making it impossible to identify which one might pass its expiration date first.