Researchers at the City University of Hong Kong have developed a lollipop-like device to simulate nine tastes and seven smells in virtual environments.
Virtual environments grow more immersive with each new generation of virtual reality (VR) headsets. Even affordable units can provide a convincing visual and auditory experience with high-resolution displays and advanced sound systems. However, the illusion often falters due to the absence of touch, smell, and taste.
Significant progress has been made in developing tactile interfaces, and practical solutions are likely to emerge soon. By contrast, technologies for integrating taste and smell into virtual experiences remain in their early stages. Researchers at the City University of Hong Kong may help bridge this gap with a new device. Resembling a small lollipop, it is designed to simulate taste and smell in virtual environments.
The device functions much like an actual lollipop, with users holding it by a stick and licking it. It can deliver up to nine flavours, including sugar, salt, citric acid, cherry, passion fruit, green tea, milk, durian, and grapefruit. Since taste and smell are closely linked, the lollipop also diffuses up to seven odours into the surrounding air.
Flavours are created using food-grade chemicals embedded in an agarose gel. Applying a voltage to the gel triggers iontophoresis, which moves the chemicals to the device’s surface. Higher voltages intensify the flavours, while lower voltages produce milder tastes. A seven-channel odour generator adds complementary scents. Unlike electrostimulation devices that require high voltages, this lollipop operates safely at two volts or less.
The researchers see potential beyond VR, such as in healthcare for standardized taste tests or virtual grocery stores where users could sample foods before buying. However, the current design requires reloading with chemicals after about an hour, which might inconvenience users. Additionally, it remains to be seen whether licking a plastic lollipop will appeal to users or if the nine flavours and seven scents can realistically mimic a variety of foods.
Reference: Yiming Liu et al, Miniaturized, portable gustation interfaces for VR/AR/MR, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2412116121
