Laura Waddell and her family have long worried she would be badly hurt in a fall in her New Smyrna Beach condo and no one would know. She has taken spills before because of her scoliosis, a degenerative back problem.

"Sometimes there's a big fracture, and I just go down," she said. And she is often alone in the condo while her husband, Dewey, is away during the week running the family's business in Leesburg.

So when the family found an electronic monitoring service that allowed her husband and two grown children to check on her from out of town, "it was a godsend," Waddell said.

Overseeing from afar those at risk is a hot issue for working caregivers, and the technology needed to do so is available. But policy makers and others have long fretted that those needing help would resist electronic monitoring as an invasion of privacy.

Now, Big Brother has arrived -- and people are rolling out the welcome mat. As vendors make in-home monitoring systems widely available, seniors and others with health problem such as Waddell, 58, are mounting little resistance. Many are embracing the gadgetry as an aid to remaining independent.

Home monitoring customers total only a few thousand nationwide, according to half a dozen monitoring companies surveyed by The Wall Street Journal. The most common systems use wireless motion or contact sensors on doorways, windows, walls, ceilings, cabinets, refrigerators, appliances or beds to track seniors' movements.

Temperature sensors gauge heat and air conditioning. If an elderly person enters the bathroom and doesn't come out, or other typical activity patterns aren't recorded in the home, word can be sent to family members, 24-hour response workers or both. The systems also offer hand-held or wearable "panic buttons."

The QuietCare system the Waddells use is monitored by response workers. Family members can receive e-mail updates if they want.

Many seniors draw the line at some kinds of surveillance. Many protest against the presence of video cameras, says Majd Alwan, who conducted several small studies of monitoring systems when he was a professor at the University of Virginia. They see motion and contact sensors as less invasive, says Alwan, now director of the Center for Aging Services Technologies, Washington, D.C., a nonprofit research group.

Also, most seniors need time to get used to the idea. When 94-year-old Christine Martin's son Marty suggested monitoring her in her Sarasota home, she objected at first, saying "she didn't want anything spying on her," said Martin of Buford, Ga.

Nevertheless, if technology helps delay the time when a senior must be admitted to a nursing home, Alwan's research found, a large majority of seniors are willing to accept it. Christine Martin cherishes her independence; she also remembers a sad mishap involving her late sister, who died at home but wasn't found until two days later. Soon, she agreed to monitoring, and found she likes it. Knowing Marty "can tell when I'm getting up in the morning," Martin said, "I feel safer."

Among about 80 seniors in Alwan's studies, only one mounted any lasting resistance to being monitored; after the research was complete, many protested when the systems were removed from their homes, Alwan says. The setups also reduced caregiver strain without reducing the time family members spent with elders.