Swedish scientists have now created such a system for use in VR gaming, and it could actually help people regain their lost sense of smell.

Led by Stockholm University's Prof. Jonas Olofsson, researchers from that institution and Malmö University recently developed a 3D-printed prototype device known as the Nosewise Handheld Olfactometer.

In its present form, the tool is mounted on the underside of an off-the-shelf HTC Vive handheld game controller. It incorporates four vertically oriented scent reservoirs, each one containing a different scented liquid absorbed into a sponge-like material. Additionally, each reservoir is sealed by one stepless valve at the top, and another at the bottom.

As long as both those valves remain closed, the user can't smell the liquid within. When the Olfactometer is activated, however, the valves on the reservoirs open to varying degrees. An onboard fan then draws air up through the bottom of the reservoirs and out the top into a single shared tube, which wafts the combined scents up to the user's nose.

It's possible to simulate various odors by mixing different scents in different ratios – a linked gaming computer determines which odors are released at which points in the game. The Olfactometer can be manually activated via the controller, or it can be set to self-activate whenever it gets within close range of the user's VR headset. And while other odor-delivery systems have been incorporated into such headsets, Nosewise is claimed to be considerably less bulky and intrusive.