Nebula: an affordable open-source and autonomous olfactory display for VR headsets

Charles JAVERLIAT, Pierre-Philippe ELST, Anne-Lise SAIVE, Patrick BAERT, Guillaume LAVOUE.

Conference on Virtual Reality Software and Technology (VRST), 2022.

[Paper]

Description

The impact of olfactory cues on user experience in virtual reality is increasingly studied. However, results are still heterogeneous and existing studies are difficult to replicate, mainly due to a lack of standardized olfactory displays. In that context, we present Nebula, a low-cost (less than 100€), open-source, olfactory display capable of diffusing scents at different diffusion rates using a nebulization process. Nebula can be used with PC VR or autonomous head mounted displays, making it easily transportable without any external computer needed.

Nebula can be easily replicated using a 3D printers and some basic electronic skills. On this repo, you will find anything needed in order to build our proposed olfactory display.

How does it work?

Nebula create an odorant mist using an ultrasonic atomizer, powered by a pulse width modulated signal (PWM). As a result, increasing the duty cycle results in an increased rate of diffusion. This modulation, handled by a micro-controller (we used an Arduino Nano Every) allows Nebula to reach several olfactory intensities.

In addition to the atomizer, we used two fans which are useful to control our air flow. The smallest one, 5VDC 25x25x6mm, is always active and forces a constant air flow to be able to smell the odor more rapidly after its diffusion and mitigates the pressure drop when enabling the extraction fan. This one is a 12VDC 40x40x20mm, much stronger, that runs for 2 seconds in order to extract the remaining odorant and thus improve the reactivity of the device.

Nebula is ready to be used with Unity (PC VR built or in editor), using the provided Unity-Package or scripts from the Nebula-UnitySoftware folder. Furthemore, Nebula works standalone using an Android Archive Library using the provided package on your own built scene. (Tested on a Meta Quest 2)

Repository Structure

• Nebula-CAD contains all STL files (ready to print), a PDF version of the wiring diagram, a list of the necessary components and some printings recommendations.
• Nebula-Experiment contains results and the unity project used in our experiment described in our paper.
• Nebula-Firmware contains code for the microcontroller used (Arduino Nano Every).
• Nebula-UnitySoftware is the Unity project using Nebula in VR including a sample scene with an orange ready to diffuse when approached to the nose !

Release content

• Nebula-UnityPackage Unity Package which includes everything needed to bring Nebula into your project unity. Includes Android Studio project for AAR files generation.
• Nebula-PCSampleScene sample scene included in the repository built that countains a ready-to-use application for Nebula.
• Nebula-SampleScene same as above but built for Meta Quest 2.

How to install

• Download the lastest Nebula.unitypackage on the Release section.
• Open your Unity project or create a new one.
• Configure .NET 4.x API Compatibility Level MANDATORY on your project (Edit => Project Settings => Player => Other Settings => Api Compatibility Level => .NET 4.x).
• Import Nebula.unitypackage previously downloaded (Assets => Import Package => Custom Package) and check All => Import.
• Install OpenXR and XR Interaction Toolkit, you have to install them if you wants to use the provided sample scene (Windows => Package Manager => Unity registery => Search for Open XR Plugin and XR Interaction Toolkit => Install).
• If needed : re-open the project.

Contacts

• Pierre-Philippe Elst (Engineer) : pierre-philippe.elst@enise.fr
• Charles Javerliat (PhD Student) : charles.javerliat@enise.fr
• Guillaume Lavoué (Professor) : guillaume.lavoue@enise.fr

Citation

@inproceedings{javerliat2022,
  title = {Nebula: An Affordable Open-Source and Autonomous Olfactory Display for VR Headsets},
  author = {JAVERLIAT, Charles and Elst, Pierre-Philippe and Saive, Anne-Lise and Baert, Patrick and Lavou{\'e}, Guillaume},
  booktitle = {Proceedings of the 28th ACM Symposium on Virtual Reality Software and Technology},
  year = {2022},
  month = Nov,
  doi = {10.1145/3562939.3565617},
}