Wannado City is helping parents keep better track of their kids with radio-frequency identification chips embedded in wristbands.

The $40 million Fort Lauderdale, Fla., theme park, which opened in August, issues RFID wristbands to visitors as part of general admission. The wristbands have a microchip from Texas Instruments Inc. that wirelessly transmits a signal to antennas in reader devices from RF Code Inc. that are positioned throughout the 140,000-square-foot facility. The system combines passive and active RFID tags and readers.

Visitors to Wannado enter the park and register their names. SafeTzone's Real-Time Locating System links together the frequency bands among the visitor tags associated with a particular group. Visitors can locate other members in their group by using any of the five touch-screen kiosks located throughout the park. All are linked to the software and database.

The watchlike plastic bracelet, which holds the active RFID chip, transmits a signal every 12 to 15 seconds. At Wannado City, 42 RF readers search for the signal as visitors walk through the firehouse, the hospital, and other play areas where children ages 4 to 11 can explore a world where they become doctors, dentists, firefighters, actors, television news reporters, and airplane pilots. Each antenna creates its own zone. Most zones in the park are about 100 feet.

"It's a PC-based system that runs through a fiber network to a server," says Curtis Parks, Wannado's general manager, who recently joined the company from Wet 'n Wild in Las Vegas, which also uses the SafeTzone technology. "We use the system for location services, but you can set up the software to send an E-mail alert if the person wearing the bracelet wanders outside the radius the readers can detect."

To locate the children in the group, parents step up to a kiosk, wave the wristband over the machine, and an electronic map of the venue appears. Coordinates are marked on the map, enabling the person to quickly find where in the park others are located. SafeTzone, which runs as a standalone system, could find a home at additional sites in the near future. Wannado plans to open theme parks in Meadowland, N.Y., and Chicago in the next two years.

SafeTzone already is in four other theme parks throughout the United States: Paramount's Great America in Santa Clara, Calif.; Wild Rivers Water Park in Irvine, Calif.; Dollywood's Splash Country in Pigeon Forge, Tenn.; and Wet 'n Wild in Las Vegas.

The tags transmit about 300 feet in typical environments; however, without competing radio waves, such as other wireless networks, to run interference, the devices can transmit up to 1,000 feet. Water does weaken the signal for the active tags somewhat, but not enough to cause real problems.

It's almost a perfect application for a ski resort, where skiers race down the mountain to re-enter lift lines. Steamboat Springs Ski Resort in Colorado is slated to begin making the brackets with tags available in November to season pass holders, ski school participants, and families and groups that want to keep track of one another. The base of the mountain will have sensors, as will the ski lifts.

Similar to Wannado, sections of the resorts are being divided into zones, and kiosks set up to locate others traveling in the group, making it easy to tell if the person is on lift No. 4 or at the top of the mountain, for example. The tags won't be used as lift tickets this season, says Regan Kelly, executive VP at Safety Zone Technologies Corp., who co-founded the company in January 2000, but that the resort is reviewing particular application.