Air-writing application

Engineering students at Duke University have taken advantage of the accelerometers in mobile phones to create an application that enables users to write short notes in the air with their phone and have that message automatically sent to an e-mail address.

Accelerometers are the devices in phones that not only keep track of the phone's movements, but make it possible for the display screens to rotate from landscape to portrait modes depending on how the phone is rotated. These devices are always on, so there is no additional burden on the phone to use the new application.

'We developed an application that uses the built-in accelerometers in cell phones to recognise human writing,' said Sandip Agrawal, an electrical and computer engineering student at Duke's Pratt School of Engineering, who with Duke graduate student Ionut Constandache developed the so-called PhonePoint Pen.

By holding the phone like a pen, a user can write short messages or draw simple diagrams in the air. The accelerometer then converts the gestures to images, which can be sent to any e-mail address for future reference.

Agrawal, a Pratt engineering undergraduate fellow, received the inaugural Hoffman + Krippner Award for Excellence in Student Engineering for the development of the PhonePoint Pen application. The award, created by the German technology firm Hoffman + Krippner, was presented on 9 June during the 2009 Sensors Expo and Conference in Chicago.

While the first-generation application permits the writing of short messages or simple drawings, it is only a matter of time before the prototype system will be able to handle larger and more complex air-writing capabilities, according to Agrawal's mentor, Romit Roy Choudhury, assistant professor of electrical and computer engineering.

Although challenges still remain to broaden the capabilities of the PhonePoint Pen, the engineers are confident they can be solved. Currently, air-writers must pause briefly between letters, which can slow down the process and rules out the use of cursive writing. Also, each letter must be written large.

Improvements would come as a result of improved algorithms and more sophisticated accelerometers, the scientists said.

Roy Choudhury expects that the PhonePoint Pen prototype will be available for download within the next few months.