RFID, GPS Technology and Electronic Surveillance

RFID-enabled Device Sounds an Alarm When Someone Tries to Leave Home

The PureRFid Companion system, sold to consumers, is designed to trigger alerts when household members wearing RFID-enabled wristbands near a doorway.

April 7, 2010

RFID Journal - PureRFid, a new startup created by RFID solutions provider Vuance, has launched a product for in-home use in the United States, to help families track relatives at risk for wandering away. The anti-wandering system, which acts as an audible alarm, can be installed in a home and sound an alert if someone wearing an RFID-enabled wristband nears a doorway.

The Companion anti-wandering system, which consists of a wristband and a door alarm containing an RFID interrogator, became commercially available on Apr. 2. The system can be purchased directly from PureRFid, or through resellers of health-care products. Prior to launching the Companion, the company had been testing prototypes of the system in such locations as the Vuance office, as well as at an Israeli research and development facility, says Kevin Michael, Vuance's VP of operations.

The Companion RFID wristband contains a 433 MHz active RFID tag.

Vuance decided to market a system such as this in the United States in order to provide a tool for the growing number of families caring for members suffering from Alzheimer's, or some other type of dementia, in their homes. The company's goal was to devise a system that was so simple it could be installed by users in their homes, and featured a wristband that would be comfortable and attractive enough that an individual would not mind wearing it. The door alarm is also designed to have a low profile, so that visitors would not notice it in the doorway.

"It's very unobtrusive," Michael says. "It's not something you would have to explain."

The gray plastic wristband contains a 433 MHz active RFID tag (1.4 inches in width and 0.4 inch in thickness) that contains a motion detector and a battery with a life span of approximately three years. The tag uses a proprietary air-interface protocol to beacon its unique ID number every five seconds when stationary, and every three seconds while in motion. The alarm device, powered by a 12-volt adapter that plugs into a wall outlet, can be attached above a door with two-sided adhesive tape, and is designed to read a tag up to 4 feet away.

The alarm device comes with one or more wristbands, each encoded with a unique ID number also programmed into the door alarm. A Companion door alarm recognizes only the wristband tags with which it is sold, so Companion tags packaged with a different unit would not trigger an alarm. The door alarm features an infrared emitter that creates an IR field across the doorway. If the device's RFID reader captures a nearby wristband's ID number, it will sound an 85-decibel continuous alarm, says Jason Clute, PureRFid's technical services manager—but only if it senses that someone is actually walking through the IR field. (The purpose of this function is to prevent the issuance of false alerts.) The device continues to emit an alert until the tag moves beyond the read range.

The door alarm can be configured by a user to compensate for different circumstances within a particular home. The received signal strength indication (RSSI) threshold can be set to a different level, for instance, thereby increasing or decreasing the read range. This may be necessary in a household in which, for example, a chair is located near the front door and the wristband wearer often sits in that chair, in close proximity to the alarm.

PureRFid also intends to launch a similar product for nursing homes and other facilities, known as Companion Plus. That version would employ an RFID interrogator instead of a door alarm, and would support the use of multiple readers connected to a network, to monitor a larger number of individuals and doorways. In this case, a software package would accompany the Companion Plus product that could be installed on the user's PC, with readers connected to the PC via Ethernet cables that plug into to a box connected to the computer via a USB port.

In this case, if an individual walks through the doorways, the interrogator would not emit an audible alarm. Instead, the system could be set up to issue a text message or page to specified staff members. According to the company, the release date of this product has not yet been set.