The archive · Product Ideas · Product decision · 2023
CityU and Beihang's soft scent wearables give VR smell — nine scents in 1.5 seconds
Two soft wireless wearables — an upper-lip patch and a nine-scent mask — heat scented wax to release smells in ~1.5 seconds, synced to what VR users see.
City University of Hong Kong · Beihang University
What it had to solve
Virtual reality faithfully reproduces sight, sound and touch but not smell, and earlier odor generators were bulky room-filling instruments that were slow to switch scents. The teams wanted an olfaction display light and fast enough to wear under a headset.
How it works
Virtual reality reproduces what you see, hear and touch, but a smell has always been missing. Researchers at City University of Hong Kong and Beihang University set out to close that gap with two soft, wireless, wearable olfaction interfaces, reported in Nature Communications in May 2023.
The first design is a flexible patch about five centimeters long that mounts on the upper lip with two scent cells; the second is a face mask holding nine scent cells whose combinations can produce many more odors. Each cell stores liquid perfume in paraffin wax that a tiny heater warms to around 50 °C, melting the wax to release the odor on demand, with Bluetooth chips coordinating release with the virtual scene.
The team produced about 30 scents in total — rosemary, mojito, pineapple, pancake and even durian — and timed detection at roughly 1.5 seconds, fast enough to follow what a wearer sees. In an experiment, 11 volunteers recognized the scents with an average success rate of 93 percent, including mint, jasmine, lavender and pineapple.
Demonstrations paired the devices with 4D movies, a VR game and online teaching, and the researchers suggested uses from evoking memories to letting separated families sense an absent member's smell. Co-lead Xinge Yu noted that earlier generators were large and leaked odors across a room, whereas these devices keep the scent source within centimeters of the nose.
Why it lands
- Placing the scent source on the body — centimeters from the nose — made response fast enough to follow VR scenes instead of filling a room.
- Heated paraffin wax with liquid perfume gave each cell a simple on-off switch, so nine cells in a mask could combine into far more smells.
- Wireless, programmable control meant the wearer's position and actions in VR could trigger the right scent at the right moment.
- The soft, flexible formats attached to skin or a mask, which is what previous bulky, room-scale olfaction machines could not do.
What it did
In a study with 11 volunteers, wearers recognized the generated scents with an average success rate of 93 percent, with detection within about 1.5 seconds. The work was published in Nature Communications in May 2023 and reported widely — framing smell as the next sensory channel that VR interfaces could actually deliver.
What you can take
A missing sense is a design brief: when room-filling scent machines were too slow for VR, shrinking the generator to the nose made smell fast, local and wearable.
Since then
The paper became one of the most covered demonstrations of "Smell-o-Vision" for VR, with New Scientist, The Verge and Scientific American reporting the 93 percent recognition rate and the 1.5-second response. The teams said the next step was a next-generation system with shorter response time, smaller size and higher integration density for virtual, augmented and mixed reality — an olfaction channel still waiting to become a consumer product.
Sources
- CityU invents wireless olfactory feedback system to let users smell in the VR world
- Researchers hope this tiny wearable could become Smell-o-Vision for VR
- High-tech face mask lets you smell things in virtual reality
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