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Barcode Education » Wand or Pen Readers

Wand readers are the lowest cost "entry level" technology used to read bar codes. Most wands look very much like ordinary pens, designed to be held in much the same way. Wands usually have no moving parts and rely on the user moving the optical head of the wand over the code to produce the scanning signal for decoding. Most wands are of the so called "dumb" type, meaning that their only function is to convert the optical signal seen at the tip into an analogue electrical signal that is then fed, usually via the attached cable, to the host device for decoding (Wand Interface type).

An extension of the basic wand reader is to place some decoding and/or memory storage in it. Such devices are usually described as "smart", or "intelligent" wands. They process the signal before transmitting to the host (e.g. converting to an RS232 serial output signal). "Memory" wands serve a similar function but have on-board memory to store the data for later downloading to a host device.

The common features of all wand devices are that they require the tip or head of the device to contact with and move across the bar code or label. This provides a number of obvious and immediate limitations:

» The surface being read must be suitable for having the wand passed over it; it must be robust to survive frequent readings. Codes printed on paper based materials can suffer wear, leading to reading difficulties.

» The user must be able to get close to the code so that they can easily "swipe" it with the wand.

» Very small or very large codes can be difficult for users to scan.

» It takes some practice to develop the required "knack" of obtaining good first time reads; novices sometimes experience difficulties.

» The surface bearing the code must adequately reflect the light/dark differentiation. In an attempt to protect delicate codes, users sometimes place some form of clear plastic protection over them. However, if the plastic itself is too reflective (or too thick), the wand will not be able to get an accurate image from the code.

» Wands really need to be used on codes that are on a flat surface; reading around the curve of a cylindrical object is either very difficult or impossible.

» Wands are not really suited to "high volume" applications. Apart from wear and tear on wands, wear and tear on users can be a bigger problem!

Despite these limitations, wands are a very popular choice for low volume/close proximity type applications. Low power consumption makes them suitable for attachment to battery powered hand held devices and their biggest benefit is of course their relatively low cost.

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