Settings in virtual and augmented reality are modifying the way users see and hear the world around them. There's already haptic feedback for the sense of touch and a VR version of Smell-O-Vision for smell. Only one important sense remains: taste.
To fill the gap, researchers at the University of Hong Kong developed a new interface for simulating taste in virtual and extended reality (XR from extended reality). The same team had previously worked on other systems for wearable interfaces for tactile and olfactory feedback. To create a more "immersive VR experience," they turned to adding taste sensations, says Yiming Liu, co-author of the team's research paper published today in the Proceedings of the National Academy of Sciences.
A device that you can lick into the shape of a lollipop can produce nine different flavors: sugar, salt, citric acid, cherry, passion fruit, green tea, milk, durian and grapefruit.
Each flavor is produced from food grade chemicals embedded in an agarose gel case. When voltage is applied to the gel, the chemicals are carried to the surface as a liquid which then mixes with saliva on the tongue like a real lollipop.
Increase the voltage and you will have a stronger taste.
Initially, the researchers tried various methods to simulate taste, including electrical stimulation of the tongue. But the other methods had limitations, were too bulky or less secure. So the researchers chose to chemically dispose of the flavor through a process called iontophoresis.
Iontophoresis moves chemicals and ions through a hydrogel and has a low electrical energy requirement. With a maximum limit of 2 volts the device (is within the human safety limit of 30 V), is considered capable of effect.
Some of the potential applications mentioned by the authors include taste tests, virtual grocery shopping, and other environments for exploring food tastes. However, the current system is limited to one hour of use due to gel depletion and supports few flavors.
A future device will aim to extend runtime, increase flavor complexity and improve usability, marking the beginning of a new range of possibilities in XR interfaces.
https://doi.org/10.1073/pnas.2412116121
