Ultra-Haptics is a system for creating haptic feedback in mid-air. Waves of ultrasound displace the air, creating a pressure difference. By causing many waves to arrive at the same place simultaneously, a noticeable pressure difference is created at that point. With this method, we are able to create multiple, concurrent points of haptic feedback in mid-air.
New Scientist has coverage of a system that uses an array of 320 ultrasound speakers set behind a touchscreen to generate beams of high-frequency sound waves. The waves are linked to the software running the displayed content and interact to create hotspots that give different sensations as people move their hands.
“What you feel is a vibration. The ultrasound exerts a force on your skin, slightly displacing it. We then turn this on and off at a frequency suited to the receptors in your hand so that you feel the vibration,” says Carter.
“A 4-hertz vibration feels like heavy raindrops on your hand,” he says. “At around 125 Hz it feels like you are touching foam and at 250 Hz you get a strong buzz.”
UltraHaptics could be used to make invisible sliders for in-car entertainment systems, Carter says, so drivers could feel their way to the desired volume. And people whose hands are often dirty, like chefs or mechanics, could use invisible haptics to flip through manuals or recipes.
We introduce UltraHaptics, a system designed to provide multi-point haptic feedback above an interactive surface. UltraHaptics employs focused ultrasound to project discrete points of haptic feedback through the display and directly on to users’ unadorned hands. We investigate the desirable properties of an acoustically transparent display and demonstrate that the system is capable of creating multiple localised points of feedback in mid-air. Through psychophysical experiments we show that feedback points with different tactile properties can be identiﬁed at smaller separations. We also show that users are able to distinguish between different vibration frequencies of non-contact points with training. Finally, we explore a number of exciting new interaction possibilities that UltraHaptics provides.