Smell machines, so-called olfactometers, can smell in a VR environment. The first is a "tasting game" in which users smell wine in a virtual cellar and earn points for guessing the aroma of each wine correctly. Stockholm University and Malmö University have collaborated to develop new technology that can be printed on 3D printers. The research, funded by the Marianne and Marcus Wallenberg Foundation, was recently published in the International Journal of Human Computing Research.
Jonas Olofsson, professor of psychology at Stockholm University and leader of the research project, said: "We hope that the possibilities of the new technology will allow smell to play a more important role in game development.
In the past, computer games focused primarily on what we could see—moving images on a screen. The other senses are absent. But an interdisciplinary research team at Stockholm University and Malmö University has now built a scent machine that can be controlled by a gaming computer. In the game, participants move around a virtual wine cellar, pick up virtual wine glasses containing different types of wine, and guess the aroma. The small scent machine is attached to the VR system's controllers, and when the player lifts the glass, it releases a scent.
"The possibility of shifting the sense of smell from a passive to a more active one in the game world paves the way for the development of entirely new smell-based game mechanics based on player actions and judgments," says Simon Niedenthal, Interaction & Judgment. Games researcher at the University of Malmö.
The olfactometer consists of four different valves, each connected to a channel. There is a fan in the middle that draws air into the tube. With the help of a computer, the player can control the four channels, causing them to open to different degrees, providing different mixes of scents. A scent blend that mimics the complexity of a real wine glass. The game has different difficulty levels with increasing complexity.
"Just like ordinary computer games, the harder the player, the better; the scent game can also challenge players who already have sensitive noses. This means that the scent machine could even be used to train wine tasters or perfumers," says Jonas Olofsson.
All the code, blueprints, and instructions for the machine are publicly available online, as is the code for the virtual wine tasting game. The research team at the Sensory-Cognition Interaction Laboratory at the Department of Psychology at Stockholm University now hopes that scented computer games can be used for other purposes.
"For example, for those who have lost their sense of smell after COVID-19 or other reasons, the new technology could mean the opportunity to restore their sense of smell with the help of game-based training," says researcher Jonas Olofsson of the team leader.
Smell training is what doctors recommend for people who have lost their sense of smell from colds and other viruses, but according to Jonas Olofsson, many people stop because it's becoming too boring.
Jonas Olofsson said: "I hope that the fact that the drawings and code are publicly available as 'open source' will bring opportunities for game companies to start using new technologies to create new commercial products for scent training.
According to Simon Niedenthal, "open source" facilitates the accessibility, reproducibility and comparison of research results. It also helps create a cohesive research and design community within the field of game development.
"But it also means that the cost of the device is significantly lower and more people can use it. For us, this is very important," says Simon Niedenthal.
"We believe in open science, that research results should be available to the public, and that other researchers should be able to replicate our results. With the help of our research, others can build scent machines and explore new ways to use scent in games," Jonas Olofsson explain.
The olfactometer technology was developed by Peter Lundén, a research engineer at Stockholm University and a member of the SCI LAB research team.