Do I really care which kid leaves? I just want kids to leave only with permission. What I want is not RFID but electronic article surveillance (EAS).
Three types of EAS systems dominate the retail industry. In each case, an EAS tag or label is attached to an item. The tag is then deactivated, or taken from an active state where it will alarm an EAS system to an inactive state where it will not flag the alarm. If the tag is a hard, reusable tag, a detacher is used to remove it when a customer purchases the item it's attached to. If it's a disposable, paper tag, it can be deactivated by swiping it over a pad or with a handheld scanner that "tells" the tag it's been authorized to leave the store. If the item has not been deactivated or detached by the clerk, when it is carried through the gates, an alarm will sound.
It looks like the detectors cost about $1000-$2000. Labels are cheap, 2000 for about $100. The labels are deactivated using a "detuner" which costs about $300. Now the question is, is it ok for the kid to stand next to the deactivator for too long?
Ahh, here's a good activate/reactivate system. Used widely in Europe, the electromagnetic (EM) system relies on a magnetic, iron-containing strip.
What most people refer to as an electromagnetic tag is actually a metal wire or ribbon that has high permeability, making it easy for magnetic signals to flow through it, according to Sensormatic's EAS Product Co. CTO Hap Patterson. "When we drive the tag, flux is being allowed to flow through the tag until it's saturated," he says. "When it's saturated, from a magnetic perspective, it begins to look like air. Saturation occurs abruptly and is an important part of the design of the tag."So, activate the kid when they come in, and deactivate them on the way out. Here's another view from "tagcompany". Posted by torque at November 23, 2004 4:58 PM | TrackBack