Harry Potter-Like Clock Tracks Family Members

Each time the family member's phone comes into range of one of the towers labeled "work," "home" or "school," the software sends a signal through the network back to the Whereabouts Clock at home. The clock interprets the signal and uses it to move an image of the person's head into the appropriate area. The image moves into "elsewhere " when the person's mobile phone is in an undesignated area.

"This tracking system isn't about communicating what people don't know. It's about telling families about things they already know. It's about reassurance and families really like that," said Sellen.

Her team tested the device with a handful of families to get specific feedback.

Should a person's face move from one area to another, say from "home" to "school," the clock will bong a notification. Family members away from home can also send a text message to the clock that people at home can read. So if mom is going to be home late from work, she can send a note saying as much.

"One of the things that's praiseworthy is the way that it accommodates people's privacy," said Bill Gaver, professor of design at Goldsmiths College at the University of London in England.

But even with such an ambiguous system, people still might not have as much privacy as they think, said Gaver.

For example, if someone's image is in the "elsewhere" region for an extended amount of time, it could raise suspicion.

What's surprising, said Sellen, is that none of the test families had issues with privacy. "They explained to us that knowing the whereabouts of family members is about family life. Even teens didn't have a problem," she said.

Sellen said that although the researchers were impressed with family testing results and think that there is potential for a product, Microsoft has no immediate plans to create one. For now at least, the magic clock is relegated to the world of fiction -- and magic.

The Whereabouts Clock

Microsoft Research Cambridge

Sprint's Family Locator

Tracy Staedter's blog: What the Tech?