Smart Watches Can Now Track Your Fingers in Mid-Air

Smart watches can now track your fingers in mid-air

A new sonar technology has been developed by scientists including those of the Indian origin that allows a person interact with mobile devices by writing or gesturing on a tabletop, a sheet of paper or even in mid-air.

FingerIO is an app that tracks fine-grained finger movements by turning a smartphone or smartwatch into an active sonar system using the device's own microphones and speakers.
Users can even interact with a phone inside a front pocket or a smartwatch hidden under a sweater sleeve and this made possible because of the fact that sound waves travel through fabric and do not require a line of sight.

FingerIO can accurately track two-dimensional finger movements to within 8mm, which is sufficiently accurate to interact with today's mobile devices was demonstrated by the researchers at University of Washington (UW) .

Lead author Rajalakshmi Nandakumar, doctoral student at UW, said that a person or an user can't type very easily onto a smartwatch display, so there is a need to transform a desk or any area around a device into an input surface.

Nandakumar added stating that he wouldn't need to instrument his fingers with any other sensors - he only uses his finger to write something on a desk or any other surface and the device can track it with high resolution.
Using FingerIO, one could use the flick of a finger to turn up the volume, press a button, or scroll through menus on a smartphone without touching it, or even write a search command or text in the air rather than typing on a tiny screen.

FingerIO turns a smartwatch or smartphone into a sonar system using the device's own speaker to emit an inaudible sound wave.

That signal bounces off the finger, and those "echoes" are recorded by the device's microphones and used to calculate the finger's location in space.

Using sound waves to track finger motion offers several advantages over cameras and other technologies like radar that require both custom sensor hardware and greater computing power, said assistant professor Shyam Gollakota. Then comparisons were made between the touchpad tracings to the shapes created by FingerIO's tracking.

The result shown was that the average difference between the drawings and the FingerIO tracings was 0.8 centi meters for the smart phone and 1.2 centi metres for the smart watch.

"Given that your finger is already a centi metre thick, that's sufficient to accurately interact with the devices," said graduate student Vikram Iyer.