Are Passive Tags Sufficient for PCs?

Published: November 18, 2009

Do passive RFID tags provide high enough read rates when applied to personal computers, or are active tags necessary?

—Name withheld

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That depends on what you are trying to achieve. When I worked at a large media company, they undertook a big exercise of putting bar-code labels on every PC, monitor, printer, keyboard and so forth. This was a massive undertaking, as the firm had several thousand employees in at least 10 locations across the United States. My computer was associated with my name—but no one ever came around and scanned the bar codes ever again, so as soon as items were switched to different employees, the data became worthless.

Had the company placed an RFID tag on each item, then someone could have come around with a handheld and taken inventory in each room in only a few seconds. The read rates are high, and accuracy is also high as long as the tag is placed on the plastic housing and away from internal metal components. It is usually possible to find a place where you can tag each item. Moreover, Omni-ID and others have developed tags designed to work on metal, and some of these have impressive read ranges. So the bottom line is that I think you can use passive tags in this application.

If you are attempting to read over longer distances, however, then it might be necessary to use an active tag. It is also possible to add a motion sensor to active tags for security purposes, so if someone were to attempt to remove computer equipment after hours, an alarm could be triggered. (With a passive tag, you would need to trigger an alarm as an item moves through a doorway.)

—Mark Roberti, Editor, RFID Journal