The University of Washington's computer science and electrical engineering researchers are putting sonar into smartwatches and the likes in the latest attempt to improve smart device technology and how we interact with it. The researchers indicate that with the new sonar technology a person would be able to interact with mobile devices by "writing or gesturing on any nearby surface."

They have called it 'FingerIO'. The technology will track finger movements. They do this by turning the phone into a sonar system by utilizing the speakers and microphones within the device. A sound wave is emitted, followed by the signal 'bouncing off' the fingers of a user and then the speakers send data to the phone that calculates what the fingers are doing. 

Rajalakshmi Nandakumar, a graduate from UW who specializes in computer science and engineering, said: "You can't type very easily onto a smartwatch display, so we wanted to transform a desk or any area around a device into an input surface." 

Shyam Gollakota is a senior author and UW assistant professor of computer science and engineering. He says that because every device has a speaker and microphones, FingerIO should make sense from a cost perspective and can be achieved without "any special hardware." 

The team says the "margin of error" for right now is 8 millimeters in terms of the drawing functionality. According to the video (see below) you could use an entire table as a drawing surface and FingerIO will follow your fingers, but the margin of error currently makes shapes and anything else drawn illegible. This is due to the sonar echoes not being strong enough to track the finger at a reliable rate. However, it would obviously be improved and refined in the upcoming months and years. Adding microphones to devices would be the next step forward to refining finger movement tracking. 

For the more technically inclined, the technical term for the tracking of finger movements is called ' Orthogonal Frequency Division Multiplexing'.