Tech trends:

Finding the needle in the haystack

by Rebekah Bovenmyer, Photos by Alison Weidemann

Have you ever ransacked your room looking for your other tennis shoe? Or searched forever for your favorite movie only to finally remember that you lent it to a friend? Ever feel like you're actually looking for that needle in the haystack? Then you know that keeping track of things (and finding them once they're lost) can be tricky.

Think of what it must be like for a huge company like Wal-Mart to keep track of all of its products as they're shipped from the various distribution centers to its many, many stores.

One way is through radio frequency identification (RFID) tags.

"RFID tags are futuristic bar codes," says Jason Greenwood, graduate student in the RFID lab at the University of Wisconsin-Madison.

RFID tags are made of plastic and have aluminum or copper antennae in the tag. They're mainly used on the pallets and cases the products are shipped in.

Tags can be read from 10 to 20 feet away from a special reader. Readers are put along the top of a truck, over a warehouse door, on a forklift, and could even be on a store shelf one day.

The antennae in the tags communicate with the reader, and then the reader sends that information to a computer. The readers communicate with lots of tags all at once so they don't slow down the truck unloading.

So, what's in the tag?

The tags store the electronic product code (EPC). The EPC is like the universal product code, the bar code that's scanned at the grocery store. The difference is that the EPC includes an individual ID number. This ID number lets retailers follow a case as it reaches the checkpoints along the way to the store shelf.

For example, they can see that case #1587 carrying toothpaste arrived at the warehouse, was put on a truck to the store, was taken into the back room for a week, then the case was crushed after its contents were set out on the store shelves.

If a pallet is missing, managers can look back through the reader's log and find out where the pallet was last seen—at the warehouse or in the back of the store. Then they can go find it.

Now, if it was only that easy to keep track of all the stuff that comes in and out of your room.