I'm looking for an inexpensive solution to locate misplaced three-ring binders that contain product data. It doesn't happen very often—but when it does, it's a huge problem. My thought would be that a passive tag could be placed in each binder, and would located by some handheld device.
Dean (Glendale, Ariz.)
The question you need to focus on is really over what distance do you need to locate the binders. If you had a large warehouse and wanted to know precisely where a box of binders was located, you would probably need an ultra-wideband (UWB) system that would employ active tags that broadcast their location. If you knew the binders were in a storeroom and just needed to pinpoint them on a shelf, you could utilize a shorter-range passive system, in which a worker would scan the shelves with a handheld reader until coming to the right binder.
A passive system, which uses tags that reflect a signal from a reader, has a short read range, so it wouldn't tell you, for instance, that Binder 123 was on Mary Smith's desk, unless you were to put readers everywhere. Most deployments of this type that I've seen require that an employee swipe a badge, or that the system read an RFID badge at the doorway of the area in which the files are stored. When a file is taken out, the system links that file to the person's ID. So if someone else wanted to find that file, they could quickly scan the shelves, see that it wasn't not there, and then look up who checked it out last.
You mention using a handheld device to find files. Motorola offers a passive ultrahigh-frequency (UHF) handheld reader that beeps as a tag's signal gets stronger, like a Geiger Counter. This might work for your needs. The read range is probably 10 to 20 feet, maybe less, depending on how the tag is oriented, whether it is covered by other objects and so on. This could be a good, cost-effective solution if your space isn't enormous. Sweeping a facility spanning hundreds of thousands of square feet might not be the most efficient way to find the binders.
In addition, we have published a number of articles on file-tracking systems. Here are some links that should prove useful.
—Mark Roberti, Editor, RFID Journal
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