Miniaturised olfactory display
Haajari, Mohsen (2024)
2024
Master's Programme in Computing Sciences and Electrical Engineering
Informaatioteknologian ja viestinnän tiedekunta - Faculty of Information Technology and Communication Sciences
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2024-12-30
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-2024122211522
https://urn.fi/URN:NBN:fi:tuni-2024122211522
Tiivistelmä
Human sense of smell is the oldest but still least studied of all our senses. Olfactory displays (OD) are devices that are used to stimulate the human sense of smell. The integration of olfactory stimuli in digital and virtual environments remains limited by hardware challenges such as weight and size, response time, number of inlet odors, and contamination.
This thesis presented a concept of olfactory display based on digital microfluidics (DMF). DMF is a technique for manipulating microlitre droplets in virtual and programmable fluidic channels. The thesis aim was proof of concept by answering these research questions: (1) Is it feasible to use digital microfluidics for designing olfactory displays? (2) What are the potentials and limitations of digital microfluidics in this context?
The thesis includes hardware and software development and technical and human tests. As the fabrication of a DMF module is outside the thesis’ scope, commercial modules were used to check the idea's feasibility and explore limitations and opportunities for future development. A desktop olfactory display was developed, including a commercial DMF module, a micropump, a piezoelectric evaporator, and a controller board.
The device was tested using food-grade liquid odors such as rose, mint, and chicory water. Functions such as sampling, and delivering odor droplets were analyzed by video frame analysis to explore the potential and limitations of DMF in the OD context. The scented air was analyzed by PID, and it showed these odors have weak PID signals in comparison with isopropyl alcohol (IPA). The assessed response time in the PID detector was 11 seconds.
In the human study, participants were randomly exposed to three droplets of three different odors (rose, mint, and chicory water), and the task was to identify each odor through the developed software. The ratio of correct answers was 66.67% for rose, 63.33% for mint, and 50% for chicory water.
The developed concept showed the potential of using DMF in OD. In future designs, the evaporator part should be integrated into the DMF module to decrease the response time. Also, the DMF driver board needs to be redesigned to have a better power supply for handling multiple odor droplets to have a shorter response time. Furthermore, a standard library of materials needs to be developed to have a strong smell to make it easier for humans to perceive and differentiate.
This thesis presented a concept of olfactory display based on digital microfluidics (DMF). DMF is a technique for manipulating microlitre droplets in virtual and programmable fluidic channels. The thesis aim was proof of concept by answering these research questions: (1) Is it feasible to use digital microfluidics for designing olfactory displays? (2) What are the potentials and limitations of digital microfluidics in this context?
The thesis includes hardware and software development and technical and human tests. As the fabrication of a DMF module is outside the thesis’ scope, commercial modules were used to check the idea's feasibility and explore limitations and opportunities for future development. A desktop olfactory display was developed, including a commercial DMF module, a micropump, a piezoelectric evaporator, and a controller board.
The device was tested using food-grade liquid odors such as rose, mint, and chicory water. Functions such as sampling, and delivering odor droplets were analyzed by video frame analysis to explore the potential and limitations of DMF in the OD context. The scented air was analyzed by PID, and it showed these odors have weak PID signals in comparison with isopropyl alcohol (IPA). The assessed response time in the PID detector was 11 seconds.
In the human study, participants were randomly exposed to three droplets of three different odors (rose, mint, and chicory water), and the task was to identify each odor through the developed software. The ratio of correct answers was 66.67% for rose, 63.33% for mint, and 50% for chicory water.
The developed concept showed the potential of using DMF in OD. In future designs, the evaporator part should be integrated into the DMF module to decrease the response time. Also, the DMF driver board needs to be redesigned to have a better power supply for handling multiple odor droplets to have a shorter response time. Furthermore, a standard library of materials needs to be developed to have a strong smell to make it easier for humans to perceive and differentiate.