U.S. engineers have created a technology that allows a person to write a note in the air with their cell phone and send the message to an e-mail address.

Duke University engineering researchers said their invention is designed for people who have their hands full of items -- briefcase, laptop, a coat or luggage -- who need to make a note, but don't want to stop and put down all of the items they're carrying.

The technology makes use of the accelerometers in cell phones -- devices that not only keep track of the phone's movements, but make it possible for display screens to rotate from landscape to portrait modes depending on how the phone is moved.

"By holding the phone like a pen, you can write short messages or draw simple diagrams in the air," computer engineering student said Sandip Agrawal, who, with Duke graduate student Ionut Constandache, developed the PhonePoint Pen.

"The accelerometer converts the gestures to images, which can be sent to any e-mail address for future reference," Constandache added. "The potential uses are practically limitless."

The prototype is expected to be available for download within the next few months.