How to bring scents to the metaverse

It was one of those many inventions that never quite took off. In 1960, audiences watching the film “Scent of Mystery” got to experience the wonders of “Smell-O-Vision”. Mounted under the cinema seats, the system pumped out 30 different scents—from salty ocean breezes to whiffs of wine—at crucial moments in the plot. The system had its quirks. Those in the balcony complained that the smells reached them too late. Others found the scents to be too faint, or else irritatingly persistent. More novel than effective, Smell-O-Vision never really took root in Hollywood.These days the cutting-edge of entertainment is video games and virtual reality, not films. Several groups are trying to bring scents to virtual worlds. In one paper published this week in , Xinge Yu at City University of Hong Kong and Yuhang Li at Beihang University describe two wearable “olfaction interfaces”. The first is the size of a plaster, and is affixed to the skin, like a fake moustache, under the user’s nose. The second, more capable version is a flexible face mask.