If you're looking for your grandmother in the farming suburb of Iwamizawa, an hour northeast of Sapporo, your best bet may be to phone the municipal call center.

In a bid to make senior citizens — and their faraway families — feel safer, elderly residents of the Hokkaido town who live on their own are carrying around a small mobile device that tells the call center's computers where they are at all times. Each resident in the program has a social worker who also carries a device, equipped to alert them to the resident's whereabouts and to tell them at a glance whether the person is home or out. The devices work as Internet phones, so residents and their social workers can talk. Remote relatives can also phone the call center for information if they're worried.

Panasonic has been using radio- frequency identification tags to track Iwamizawa's elderly since March. The national Ministry of Internal Affairs and Communications is paying for the project, part of a program to help Japanese companies make and sell technology for daily use both in Japan and abroad.