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The future of product identification

In the future, your refrigerator might alert you when the milk has gone sour. At the supermarket, cashiers won't need to scan bar-codes because products will provide the data on their own. And packages and letters will carry electronic tags that send messages about where they are.

To make such a world possible, scientists are working on a technology called Radio Frequency Identification (RFID). An RFID tag is an electronic device that can be glued to cereal boxes, milk cartons, envelopes, and other objects. The tags store information and use radio signals to communicate with computers or sensors.

RFID tags already exist in some countries in the form of "smart cards" that store dollar amounts for users of some public transportation systems. RFID chips have also been implanted in animals to identify them, and allow owners to find them if the animals get lost. In these cases, the tags are made of silicon, the material from which most computer chips are made. However, silicon electronic tags are too expensive to be used as widely as printed bar-codes.

Now, scientists from two companies in Europe have independently taken steps toward speeding up the spread of RFID technology. They have created tags completely out of plastic materials, with the right kinds of electronic properties to transmit radio signals efficiently. The methods for making plastic tags are much cheaper than those for making silicon tags.

The tags produced by scientists from Philips Research Laboratories in Eindhoven in the Netherlands, are made from a type of plastic called pentacene, and transmit radio waves at a frequency of 13.56 megahertz. The tags produced by PolyIC in Erlangen, Germany, use a different type of plastic.

Neither type of tag is perfect yet. The plastic tags are still expensive and tricky to manufacture, and their radio signals don't travel very far.

It may be a few years yet before plastic RFIDs make their way into nearly all of our everyday objects. But when they do, there will be an amazing amount of information zooming invisibly around us.

How bar-codes work

To understand things easily, let us first learn about bar-codes. Don't be intimidated (frightened) by bar-codes. You don't need to be a rocket scientist to understand them; they are just a different way of encoding numbers and letters by using a combination of bars and spaces of varying widths.

Think of them as another way of writing, since they replace key-data entry as a method of gathering data. In business, the correct use of bar-codes can reduce inefficiencies and improve a company's productivity, thereby improving their profitability.

Simply put, bar-codes are a fast, easy, and accurate way of entering data. This may come as a surprise to you! A bar-code doesn't contain descriptive data. It is a reference number that a computer uses to look up an associated record that contains descriptive data and other important information.

For example, a bar-code found on a loaf of bread doesn't contain the product name, type of bread, or price; instead, it contains a 12-digit product number. Now, when this number is scanned by the cashier at the check-out counter, it's transmitted to the store's computer which finds the record associated with that item number in its database. The matching item record contains a description of the product including vendor name, price and quantity-on-hand.

The computer instantly does a "price look-up" and displays the price on the cash register (it also subtracts the quantity purchased from the quantity-on-hand). This entire transaction is done instantly; think of how long it would take the cashier to key in a 12-digit number for every item you wanted to buy!

A bar-code typically has ID data encoded in it, and that data is used by a computer to look up all specific information associated with the data.

Symbology is considered a language in bar-code technology. Just as you might speak French while travelling in France, a symbology allows a scanner and a bar-code to "speak" to each other.

When a bar-code is scanned, it's the symbology that enables the information to be read accurately. And when a bar-code is printed, it's the symbology that allows the printer to understand the information that needs to be turned into a label.

How bar-codes are read

Bar-codes are read by sweeping a small spot of light across the printed bar-code symbol. Your eyes only see a thin red line emitted from the laser scanner.

But what's happening is that the scanner's light source is being absorbed by the dark bars and reflected by the light spaces. A device in the scanner takes the reflected light and converts it into an electrical signal.

The scanner's laser (light source) starts to read the bar-code at a white space (the quiet zone) before the first bar, and continues passing by the last bar, ending in the white space which follows it. Because a bar-code cannot be read if the sweep wanders outside the symbol area, bar heights are chosen to make it easy to keep the sweep within the bar-code area.

The longer the information to be coded, the longer the bar-code needed. And as the length increases, so does the height of the bars and spaces to be read. There are three basic types of bar-code scanners - fixed, portable batch, and portable wireless. Fixed scanners (hand-held or mounted) remain attached to their host computer or terminal, and transmit one data item at a time, as the bar-code is scanned.

Portable batch scanners are battery operated, and store data in memory for later batch transfer to a host computer. Wireless portable scanners also store data in memory, however data is transmitted to the host in real time. This allows for instant access to all data for management decisions.

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