Smelling in the VR world? It is possible thanks to a new wireless olfactory system

A research team led by researchers from the City University of Hong Kong (CityU) recently invented a new wireless, skin-interfaced olfactory feedback system that can release various odors with miniaturized odor generators (OGs ) . The new technology integrates odors into virtual reality (VR)/augmented reality (AR) to provide a more immersive experience, with wide applications ranging from 4D movie viewing, medical treatment and online teaching .

“ Recent human-machine interfaces highlight the importance of human sensation feedback, including vision, audio and haptics, associated with broad applications in entertainment, medical treatment and VR/AR. Smell also plays a significant role in human perceptual experiences ,” said Dr. Yu Xinge, a professor in CityU’s Department of Biomedical Engineering who led the study. “ However, current smell generation technologies are mainly associated with large instruments for generating odors in an enclosed area or room, or a bulky built-in VR set“. For this reason, Dr. Yu and his collaborators at Beihang University have developed a next-generation, wearable, wireless and programmable olfactory feedback system based on flexible, miniaturized odor generator arrays.

They created two designs to release odors on demand through the new olfactory feedback devices, which are made of soft, miniaturized and lightweight substrates. The first is a small patch -like device , built into the skin that can be fitted directly to the upper lip. Thanks to the extremely small distance with the user’s nose, it can provide an ultra-fast olfactory response. Another project is that of a flexible mask with nine different types of smell, capable of providing hundreds of olfactory combinations.

The magic of the odor generators is based on a thin heating platform and a mechanical thermal actuator. By heating and melting the odorous paraffin wax to cause a phase change, different odors are released in adjustable concentration. To stop the smell, odor generators can cool the temperature of the wax by controlling the movement of the thermal actuator.

30 different scents, from rosemary to pancake

Using different paraffin waxes, the research team was able to produce around 30 different scents in total, from herbal rosemary, fruity pineapple to sweet baked pancake. It is also possible to create not very pleasant perfumes, such as the smelly durian. The 11 volunteers were able to recognize the generated scents with an average success rate of 93%. The new system supports long-term use without the need for frequent replacement and maintenance, and enables user interaction for different applications.

Most importantly, the olfactory interface can support wireless and programmable operation and can interact with users in various applications. It can respond quickly to the explosion or suppression of odors and precisely control the concentration of odors. The odor sources are easily accessible and biocompatible. In their experiments, demonstrations of 4D movie viewing, medical treatment, human emotion control, and VR/AR experience in online teaching showed the great potential of novel olfactory interfaces in various applications. For example, the new wireless olfactory system can interact between the user and a virtual subject as the user “walks” through a virtual garden releasing various fruit fragrances.

In the next phase, the research team will focus on developing a next-generation olfaction system with a shorter response time, smaller size, and higher integration density for VR, AR, and mixed reality (MR) applications.