American engineers have developed software that allows users to control their phones by squeezing and pressure without the need to install additional sensors.
The ForcePhone system developed by a team from the University of Michigan uses the handset's inbuilt speakers and microphones to detect changes in pressure and translates them into commands.
The system could theoretically serve as the right-click functionality on a computer or to allow people to dial certain numbers by squeezing the phone in a certain sequence.
"I think we're offering a natural interface, like how you turn a knob," said Yu-Chih Tung, a doctoral student at the University of Michigan’s Department of Electrical Engineering and Computer Science, who developed the system together with his supervisor, Professor Kang Shin.
"It's the next step forward from a basic touch interface and it can complement other gestured communication channels and voice."
The technology works by having the speakers emit an inaudible signal of a frequency above 18kHz. Pressing the phone’s screen or squeezing the body affects the frequency, which is registered by the microphones and translated into a command.
Currently, only iPhone 6s has a force-sensing screen and there is no commercially available device with a pressure-sensitive body.
"Having expensive and bulky sensors installed into smartphones can solve every problem we have solved, but the added cost and laborious installation prevent phone manufacturers from doing it," Tung said. "Our sound-based solution can fill this gap, providing the functionality without making any hardware modification. Everything is just software."
Tung was inspired to develop the system by the 2008 Batman movie 'The Dark Knight'. In the film, Batman turns all smartphones in Gotham City into a sonar system, which he uses to track his adversary the Joker.
ForcePhone is already the third application based on this idea. Previously, the team developed an Android application that warns distracted pedestrians of objects in their path and a system that uses sound tagging to remember indoor locations.