[Researchers continue to look for a practical and effective way to add smells, and taste, to presence experiences. The Scientific American story below describes a new effort that solves some long-standing problems, and the excerpt from coverage in MIT Technology Review that follows it provides more details. See the new article in Nature Communications for more information and three short videos. –Matthew]
[Image: The first part of Figure 4a in “Soft, miniaturized, wireless olfactory interface for virtual reality“: “A demonstration of the skin-integrated Device 1 in displaying olfaction feedback for providing an immersive experience to users during movie watching. Here, a girl in the movie is smelling a flower… while the watcher… smell[s] [a] floral odor by wearing the olfaction interface.”]
Virtual Reality System Lets You Stop and Smell the Roses
A wireless device worn on the face or lip can produce fragrances such as lavender and green tea in a virtual world
By Simon Makin
May 9, 2023
Virtual reality is already widespread in entertainment and is starting to spread to fields ranging from education to health care. But while vision and hearing interfaces are extremely advanced, and touch, or “haptics,” is improving, one key sense has been missing from the virtual world: smell.
That may be about to change. Engineer Xinge Yu of the City University of Hong Kong and his colleagues have developed a lightweight, flexible and wireless olfactory interface that can precisely deliver smells such as lavender, pineapple or green tea to VR users and more fully immerse them in scented virtual worlds. “Bringing smell into VR expands it into another dimension,” Yu says. “We wanted to develop something in a wearable, skin-integrated format that people can go anywhere with and use anytime.”
The team’s design was described in a paper published on Tuesday in Nature Communications. A key advantage is that it can control odor intensity. One demonstration in the study involved increasing the intensity of the smell generated as a woman in a four-dimensional movie brought a rose up to her nose.
Previous smell interfaces have typically used bottles of liquid perfume, an atomizer (a device that turns liquids into a fine mist) and some method of blowing the atomized droplets out. This works, but it is rigid and has limited operating time between refills, and it does not easily allow for controlling intensity. These drawbacks have made the devices less practical for VR systems.
The new design uses small paraffin wax pads infused with scents that are heated by an electrode to release an odor. A temperature-dependent resistor, or thermistor, senses the temperature, which controls the smell’s intensity. And a magnetic induction coil controls a metal plate that conducts heat away from the electrode to rapidly cool it down and shut off the scent. Arrays of these odor generators, which are millimeters in size, are incorporated into thin, flexible sheets of electronics.
The study describes two different device formats. The first is small enough that it can be stuck to a user’s top lip, but it includes only two odor generators. The second is worn like a face mask and has nine. Both are customizable with a selection of 30 odors, including gardenia, caramel, ginger, clove, mojito and coconut milk. Different combinations can be blended at varying intensities to create a palette of thousands of possible fragrances.
The proximity to the user’s nose, together with clever engineering, allows for delays between activating and receiving a smell as short as 1.44 seconds. Atomizers are faster than this, but they lack the control of the new devices and are as small as they are ever going to get, says Judith Amores, a senior researcher at Microsoft Research and a research affiliate at the Massachusetts Institute of Technology, who studies olfactory interfaces for health applications but was not involved in the study. “An advantage of this system is they could miniaturize it even more,” she says. “That’s what’s exciting.”
The study includes demonstrations of possible applications beyond just augmenting VR, including communicating messages by smell and evoking emotions. The researchers suggest the devices could even be used to alleviate depressed mood or promote recall in people with age-related cognitive decline. “Scent is directly connected to the emotional and memory parts of the brain, so there are a lot of applications related to well-being and health,” Amores says. “It could also be used as a way to do olfactory training to help people who lost their sense of smell due to COVID.”
The researchers have already started shrinking things down further. They have a system that’s two to three times smaller now, and they aim to shrink it to something five to 10 times smaller in the future. “That’s the next step,” Yu says.
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[From MIT Technology Review]
New research aims to bring odors into virtual worlds
Soon, you may be able to smell the metaverse.
By Tanya Basu
May 9, 2023
[Snip]
The higher the heat, the stronger the odor and the more easily identifiable the smell, Yu says. That means that interfaces can get very hot—up to 60° C (140° F), which is dangerous for human skin. But Yu says the interface is safe because of an “open” design that lets hot air escape, along with a piece of silicone that forms a barrier between the skin and the actual device.
In a test with 11 volunteers, the interface that goes between nose and mouth was judged safe so long as it was at least 1.5 millimeters from the nose, with a temperature at the skin’s surface of 32.2° C, or 90° F—less than human body temperature. Yu realizes, though, that a scalding hot interface attached to your face might not feel safe enough to use, and he said he and Li were testing ways to make the interface run at lower temperatures or cool down more efficiently.
Yu and Li are not alone in trying to create seamless olfactory experiences in VR. At this year’s CES, OVR Technology announced that it would release a headset containing a cartridge with eight “primary” aromas designed to mix and match.
“This is quite an exciting development,” says Jas Brooks, a PhD candidate at the University of Chicago’s Human-Computer Integration Lab who has studied chemical interfaces and smell. “It’s tackling a core problem with smell in VR: How do we miniaturize this, make it not messy, and not use liquid?”
Artists have long attempted to bring scents into entertainment. In 1960, “Smell-O-Vision” made its first and only appearance with the film Scent of Mystery, which released odors during key plot points via air conditioning. But the effort bombed: during screenings, scents were either delayed or too faint to notice.
These new interfaces are a notable development that could change how we experience VR. Olfaction is a powerful sense and a prerequisite for our mouths to detect flavor. The possibilities range from the obvious—sniffing a virtual flower field or inhaling VR food—to some less obvious applications. For example, perfumeries could test fragrances virtually.
Medically, scent-equipped VR could be helpful for people who have anosmia, or an inability to smell, according to Yu. Scents can also be therapeutic for patients with memory issues and might even help with mood. Yu told me he noticed he felt happier when he used the green tea scent in his tests. He realized that the smell was nostalgic: “When I was little, I’d have some chocolate with a green tea flavor,” he recalled. “I still remember peeling off the wrapper, and how I loved the smell.”
What stands out about these new interfaces is that they are light, small, and wireless. While the device wasn’t tested directly with a VR game, platform, or specific device, the fact that it can be used without clunky wires should mean fewer tangles, less bulk, and a more immersive experience. … [But] the miniaturized odor generators have yet to be programmed to work smoothly with existing VR headsets. “It’s hard to say how this would work in a commercial interface,” Brooks says.
Yu says next steps include testing mechanisms to release scents at the right moment. He also wants to start incorporating what he’s learned about smell into figuring out how to introduce taste in VR. Perhaps one day he can replicate the experience of biting into a green- tea-flavored chocolate candy.