Getting Smelly in Virtual Reality
Is wax the way to go?
Sterling silver Art Nouveau patch box c. 1900 from Aftelier.com
I was in Berkeley last week to visit my pal Mandy Aftel, the natural perfumer, fragrance writer, and scent enthusiast extraordinaire. One of her specialties is solid perfumes in a base of unfiltered beeswax and jojoba oil, which she sells in a custom-made sterling silver case or in repurposed antique patch boxes. A double-sided case gives you the option of two perfumes side-by-side. Mandy points out that “this actually provides three fragrances, as the two perfumes may be blended together on the skin to create a third.”
Little did I suspect Mandy’s revival of this ancient art form would be relevant to the breathless tech headlines that broke the day following my visit.
VR ‘Smell-o-vision’ may enable users to detect dozens of odors. New York Post
Researchers hope this tiny wearable could become Smell-o-Vision for VR. The Verge
New research aims to bring odors into virtual worlds; Soon, you may be able to smell the metaverse. MIT Technology Review
How to bring scents to the metaverse; VR enthusiasts turn their attentions to an evocative, but neglected, sense. The Economist
In my book What the Nose Knows, I wrote the first serious historical account of Smell-O-Vision and AromaRama, the competing movie-scenting technologies of the late Fifties and early Sixties. I was also an early employee of Digiscents, the turn of the century startup that tried to bring smell to the internet. So naturally, a paper titled “Soft, miniaturized, wireless olfactory interface for virtual reality,” screamed for my attention. Especially since it was published in Nature Communications, a high-profile journal with a hefty impact factor of 17.6.
Miniaturized, wearable odor generators that don’t require a heavy helmet would be a useful way to add an olfactory dimension to the largely audio-visual world of VR. Many such technologies have been proposed and even patented. New devices appear regularly at the Consumer Electronics Show. Ubisoft got into the act in 2016, promoting a Nosulus Rift face mask that allegedly let players of their South Park: The Fractured But Whole video game, smell a character’s in-game farts.
The Nature Communications paper runs an impressive 14 pages and includes 23 authors, most of them biosensor specialists from Hong Kong with a few from mainland China. Given the drumbeat of publicity, I was expecting some top-notch high tech wizardry.
What did I find? A flexible circuit board, a heating electrode, a Bluetooth module, and . . . scented wax. Yes, the same medium Mandy Aftel uses to such gorgeous effect in her solid perfumes.
In the device described by Liu et al., a small, thin rectangle of scented wax sits atop a layer of flexible circuitry. A Bluetooth signal activates the heating electrode which releases scent from the wax. One version of the device features two wax pods and can be fitted under the nose across the upper lip. Another version has nine wax pods and fits inside a face mask. The nine pods can be activated individually or in combination. For a given pod, more heat produces more scent.
That’s it. That’s the entire freakin’ concept.
The bulk of the paper consists of engineering data showing that the device operates as intended. The authors provide precious little sensory data. One test—tucked away in a supplementary figure—claims that odors smelled stronger as the wax is heated to higher temperatures. (A rather low bar to clear.) Another test found that users could distinguish odor concentrations produced by “fast” stepwise increases in wax temperature. “Fast” here means intervals ranging from 5 to 28 seconds.
Let’s review just how disappointing this is. The main reason Smell-O-Vision and AromaRama failed was that scenting a large volume of space—such as a movie theater—involves a time lag as the odor disperses, and another interval as the odor dissipates. This made it cumbersome to synchronize scent release to on-screen action.
Scenting a personal VR experience has neither of these constraints. It requires the tiniest amount of scent be released close to the nose. It is the ideal setup for piezo-electric micro-spritzing—basically an ink-jet mechanism that draws on a small scent reservoir. Odor intensity is controlled by how many times the piezo mechanism fires. Odor rise times are extremely fast. Why the HK/China team decided to revert to heated wax is beyond me.
If this were a class project for an undergrad engineering course at Georgia Tech or USC, I’d buy the team a pitcher of beer and encourage them to go piezo.
If Nature Communications had sent me the Liu et al. et al. et al. manuscript for review, I would have rejected it and recommended it be submitted to an applied technology journal, of which there are many.
Yiming Liu, Chun Ki Yiu, Zhao Zhao, and 20 others. (2023). Soft, miniaturized, wireless olfactory interface for virtual reality. Nature Communications 14:2297.