The Raspberry Pi-Powered Nosewise Olfactometer Adds Smell to HTC's Vive VR Hand Controllers

Researchers at Sweden's Malmö University and Stockholm University have developed a device, which aims to make virtual reality even more convincing: an open source smell-o-vision olfactometer that provides in-game odors — convincing enough to drive a wine-tasting game.

"I hope that the fact that drawings and code are openly available as 'open source' will lead to an opportunity for game companies to start creating new, commercial products for scent training using the new technology," says Jonas Olofsson, professor of psychology and project lead. "We believe in open science, that research results should be made available to the public and that other researchers should be able to repeat our results. With the help of our research, others can build scent machines and explore new ways of using scents in games."

The hardware, developed by research engineer Peter Lundén and dubbed the Nosewise Handheld Olfactometer, consists of a stepless valve olfactometer, designed for production at low cost, which attaches to HTC Vive hand controllers. Under computer control, using a Raspberry Pi Zero W single-board computer and an Adafruit 815 servo controller, the valves are opened to varying degrees and the smell provided to the user — reacting to what's happening in-game and mixing together core smells in the same way as primary colors are mixed to make a picture.

To prove the concept required a game, so the team set about building one — in which the player is given the job of "tasting" wine samples. By lifting a wine glass to their nose, the wine's smell is mixed and blown towards the user with a fan — and the player has to identify the aromas. "In the same way that a normal computer game becomes more difficult the better the player becomes," Olofsson claims, "the scent game can also challenge players who already have a sensitive nose. This means that the scent machine can even be used to train wine tasters or perfumers."

There are non-gaming applications for the technology, too, which the team found was able to capture many of the characteristics of high-end research olfactometers at a fraction of the cost: "For those who, for example, lost their sense of smell after COVID-19 or for other reasons," Olofsson explains, "the new technology can mean an opportunity to regain their sense of smell with the help of game-based training."

It's not the first time we've seen a multi-chamber olfactometer used for virtual reality gaming: earlier this year a team at the Commonwealth Scientific and Industrial Research Organization (CSIRO) and the University of Technology in Sydney used a similar system with six chambers to pump smells at subjects playing Capcom's Resident Evil 7 — finding that providing smells, which relate to the game world boosted the players' sense of spatial presence while heightening anxiety during the game's creepier sections.

The team's work has been published under open-access terms in the International Journal of Human-Computer Studies; construction instructions for the olfactometer and its Python source code are available on the Center for Open Science website under an unspecified open source license.