German researchers have developed an ultrasonic haptic speaker that allows them to display Braille numbers without contact.
Researchers at Germany’s Bayreuth University have been working to develop a special speaker system that emits ultrasound waves with the purpose of letting people read braille in midair. It does this by using acoustic force to stand in for the usual tactile embossed braille writing.
The device can create several zones in the air at the same time, where the ultrasonic waves are focused and create a pressure that a person can distinguish. At the same time, visually impaired people on such a device can recognize characters from four points in 88% of cases, which will allow the future use of such technologies for contactless interaction.
“With HaptiRead, we investigate for the first time, in a user study with blind people, the possibility of using midair haptic technology for the purpose of presenting braille text as a touchless haptic sensation,” Viktorija Paneva, one of the researchers on the project said. “Midair haptic devices consist of an array of phased ultrasonic speakers. By modulating the focused ultrasonic waves, it is possible to generate perceivable haptic points in midair. The sensation is usually described by users as a focused, gentle air breeze.”
This technology — which is made up of a 16 x 16 grid of tiny ultrasound speakers — can be used to detect the hand of the user up to a distance of 70 centimeters. The system gives commands to each emitter at different times, but if you select the appropriate phase for each, then at a certain point they will signal at the same time. Moreover, if you modulate the signal with a certain strength, then the human skin can feel a certain pressure.
The authors used to modulate the frequency signal from 100 to 200 hertz, and for the best distinguishability of the points, they used their own frequency for each of them. The device also includes a Leap Motion sensor to track the position of the hand. It allows you to automatically adjust the focus points so that they are close to the palm of your hand even if it moves.
During the test, the developers conducted a system experiment on 11 visually impaired people. They needed to bring their hand to the display and read the number shown there. Moreover, the accuracy of the experiment amounted to 88%.
“Since HaptiRead provides the possibility of reading braille through touchless interactions, it definitely represents a novel solution for reading information in public spaces such as elevators, cash machines, city maps, information booths, [and similar],” Sofia Seinfeld, another researcher on the project, told Digital Trends. “Additionally, sighted users might also benefit from it in applications involving a combination of visual and haptic feedback — for instance, imagine pressing buttons in midair or combining ultrasonic feedback with immersive virtual reality technologies in order to provide richer multisensory experiences to the user.”