Mr. Arkko, an engineer for Sweden's Telefon AB L.M. Ericsson, uses his home in Finland, which he shares with his wife and three sons, as a lab. He has connected the entire house to a wireless network so he can get updates on his computer or cellphone when the front door opens, when the laundry is dry or when his toast is ready.
"It just shows you these things are very easy and we will see far better ideas," says Mr. Arkko, noting it took him only 20 minutes to connect his toaster's status to Facebook.
He's one of a growing number of engineers, working for giant telecommunications companies or small start-ups, inventing products that can send messages—from a diaper that lets parents know their baby needs changing, to slippers that can tell when your grandmother might be headed for a fall, to a device that lets farmers know when cows are in the mood.
With nearly everyone in America already carrying a cellular phone, companies are thinking outside the box—way outside—to drum up fresh demand for their networks.
U.S. carriers are betting they can get "wireless penetration"—now around 90%—up to 300% or 400%. In plain English, that means they need every man, woman and child in the country to each use three or four wireless products, a goal that can't be accomplished with phones alone.
"From our perspective, we don't think anything is off limits," says Glenn Lurie, head of the emerging devices unit at AT&T Inc., set up last year to work with startups to create wireless products.
Wireless diapers are the brainchild of a startup called 24eight. Embedded with a cellular chip, they can send a "diaper wet" notification via text message to a cellphone. The company says they cost about two cents more apiece than normal diapers. David Schieffelin, chief executive of 24eight, says he's still searching for the right partner to help him commercialize the product.
Mr. Schieffelin was able to join with wireless carriers on another of his inventions: fuzzy slippers.
AT&T is running a clinical trial using "SmartSlippers," produced by 24eight, that are aimed at the elderly. Verizon Wireless recently made an investment in the company, and Mr. Schieffelin hopes to sell the slippers this fall directly to consumers.
The slippers will cost about $100—and a cellular plan that would allow the slippers to send messages would cost $25 a month.
If the wearer gets wobbly, an "accelerometer" in the sole—the same gizmo that makes the iPhone respond to tilts and twists—will sense trouble. The slipper will then send a text over the carrier's network to a family member or the wearer's physician.