Olfa

Olfa is a “Shazam for scent” app that helps users capture smells and the memories they trigger, turning fleeting scent moments into digital postcards and a personal archive of experiences.

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Inspiration

We chose this problem because many of us noticed how strongly scent is connected to memory and emotion. Some members of our team are perfume enthusiasts who enjoy identifying fragrance notes, while others love traveling and often want to preserve moments beyond photos. We also realized that smell often becomes meaningful during emotional transitions, such as moving to a new city, feeling nostalgic about past places, or coping with loss. However, these scent-triggered memories are fleeting and difficult to capture. This inspired us to design a tool that could record and preserve these sensory moments. Our idea was also influenced by the structure of wine flavor wheels, which help people describe complex sensory experiences, and the concept of postcards or letters that capture a moment in time.

What it does

Olfa is a wearable-assisted system that captures scent-triggered memories. When a user encounters a smell they want to capture, they press the button on the wearable device. The sensor analyzes the surrounding air by identifying chemical components and translating them into recognizable scent categories such as woody, roasted, floral, or earthy. These scent notes are displayed in the app, where the user can adjust the description to better match their personal perception. On the scent editing page, users can reorder the detected scent notes to indicate which ones they perceive most strongly. For example, if a floral scent stands out more than the others, the user can move it to the top of the list to rank its prominence. Users can also add additional notes if they detect scents that the system did not identify. This allows the experience to remain subjective and personalized rather than relying only on automated detection. After confirming the scent notes, users can optionally capture an instant photo through the app or upload an existing image to document the moment visually. They may also record a short memory or emotional reflection associated with the scent. Once the entry is completed, the system generates a digital “scent postcard” that contains the scent description, date, location, and any notes or photos the user included. Over time, these postcards form a personal archive of scent memories, allowing users to revisit meaningful moments where smell and memory intersect.

How we built it

We built Olfa through a collaborative workflow between design and engineering. Our two designers first explored the interaction model in Figma, focusing on how a user could capture a scent moment with minimal friction. We designed the mobile interface and postcard interaction flow, then used Figma Make to translate the design components into an initial interactive structure. After the design system and user flows were established, the engineer implemented the prototype locally using a React and TypeScript architecture with modular components for pages, UI elements, and utility functions. The sensing experience is powered by a simulated scent detection system that generates scent notes from predefined scent families, allowing us to demonstrate how a wearable sensor could translate chemical compounds into recognizable scent categories. We also implemented browser geolocation and reverse geocoding using OpenStreetMap to automatically attach location metadata to each scent capture. To support memory recording, the app allows users to attach photos using mobile camera input, and we experimented with applying automatic visual filters that reflect the detected scent category to create a stronger emotional connection between the image and the scent memory. The system then generates a structured “scent postcard” containing the scent notes, time, location, optional photo, and a user-written memory log, which is stored locally and displayed in a personal gallery. Throughout development we focused on building a modular architecture that separates sensing logic, scent categorization, UI components, and storage so that the prototype could later integrate real scent sensors or external APIs without requiring major changes to the interaction design.

Challenges we ran into

One of the main challenges we encountered was that this type of system does not currently exist in a widely accessible form, which made it difficult to fully visualize how it could be implemented in practice. Because capturing and identifying scent is not something that typical consumer devices currently support, we had to imagine how both the hardware and software components might work together. This required us to think beyond existing products and consider speculative possibilities, such as wearable chemical sensors and methods for translating scent data into meaningful descriptions for users. Another challenge was designing interactions around a sensory experience that is inherently subjective. Unlike images or sound, smells are difficult to describe consistently, and different people may perceive the same scent in different ways. Because of this, we had to carefully consider how the system should balance automated detection with user input, allowing users to adjust or personalize scent descriptions.

Accomplishments that we're proud of

One accomplishment we are particularly proud of is the scent postcard visualization system, which translates scent descriptions into a visual experience. Each detected scent note is mapped to a color based on its scent category, inspired by fragrance and wine aroma wheels. Instead of simply listing scent labels, the system blends these colors together to generate a soft gradient background for the postcard. This allows the postcard itself to visually represent the scent composition of the moment. For example, fresh or airy notes produce cool blue tones, while forest or woody notes introduce earthy greens and browns. As multiple scent notes are combined, their colors merge to create a unique gradient that reflects the overall scent profile. This design turns an invisible sensory experience into something users can see and revisit later, making each scent postcard feel personal and distinctive. We are proud that the interface does not just record scent information, but transforms it into a visual artifact that captures the atmosphere and emotion of the moment.

What we learned

Through this project, we learned that designing for sensory experiences requires a different approach than traditional digital products. Smell is deeply connected to emotion and memory, but it is difficult for people to describe or categorize it. This made us think carefully about how technology can help people interpret sensory experiences without replacing personal meaning. We also learned the importance of reducing interaction friction. If the process of recording a scent moment is too complicated, users are unlikely to use it in everyday situations.

What's next for Olfa

In the future, we would like to explore more advanced scent detection technology to improve how scent molecules are analyzed and categorized. As sensor technology continues to evolve, more precise detection could allow the system to identify more nuanced scent components and improve the accuracy of scent recognition. We are also interested in expanding the insight features so users can discover patterns across their scent memories. For example, the system may highlight frequently detected scent families or common emotional associations that appear across different entries. These insights could help users better understand how certain smells repeatedly appear in meaningful contexts throughout their lives. Another possible direction would be adding optional social features that allow users to share scent postcards and compare how different people interpret the same scent experience. This could reveal how scent perception varies across individuals and create opportunities for shared storytelling around sensory memories.

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