Pebbl

A snapshot of our UI

Inspiration

Recent research has raised alarm about AI’s damaging effect on cognitive skills: students relying too heavily on AI show lower brain engagement, lack of originality and lowered attention spans (Kosmyna et al., 2025). Our user research revealed that students feel overwhelmed, struggle with structuring ideas, and feel a sense of loss of ownership over their learning. Meanwhile, educators are observing the detrimental effects of mass AI overreliance while feeling helpless in terms of detecting it, and lacking healthy alternatives to suggest. This gap produced our solution: a truly and solely assistive AI tool that preserves your voice, grows your brainpower and makes learning genuinely enjoyable again. We hope to automate learning while promoting positive cognitive growth and individual originality!

What it does

Pebbl is an AI-powered learning companion and writing mentor built to fight the “brainrot” caused by overreliance on AI. Instead of outsourcing your thinking, Pebbl nudges you with smart questions, helping you dump, organize, and refine your thoughts into polished essays or academic drafts. It also includes a lecture note-taker: upload audio or video, and Pebbl quizzes you, chats about key points, and builds deep understanding. Voice input means you can brainstorm while walking, working out, or just vibing, perfect for neurodivergent learners like those with ADHD. Gamified milestones reward engagement and skill growth, keeping learning fun and active.

How we built it

We built Pebbl as an Android app using Kotlin with Jetpack Compose for a clean, interactive UI. Offline speech recognition is powered by Vosk SDK, and AI-guided prompts use OpenRouter GPT-40-mini. We structured it with MVVM + Repository, store data in Room (SQLite), and handle async tasks with Kotlin Coroutines and Flow. Only text is sent to AI, keeping audio private.

Challenges we ran into

One of the hardest challenge was to make the process of building your essay feel natural, and to make sure the questions which were asked by the AI were actually relevant, and that it understood the context enough to keep asking relevant questions, and also guiding the user to a conclusion too.

Some other challenges we ran into was how to fix the hallucinations and drifting, so that the AI knows the context and in longer conversations or essays it doesn't start asking questions which make no sense.

Finally we also had a challenge to deal with, as we knew we wanted to add some sort of achievement system to motivate users but we wanted to make sure it wasn't too distracting so the challenge was balancing gamification and learning so that milestones motivate without distracting.

Accomplishments that we're proud of

We’re proud to have built Pebbl into a fully functional, privacy-first learning and writing companion that actively fights AI-induced cognitive decline. Our AI-guided prompts, offline voice recognition, and lecture note quizzes make learning fun, accessible, and personalized. Gamified milestones motivate students while preserving their critical thinking and ownership of ideas, helping them fall in love with learning again!

What we learned

Through building this tool and interviewing several educators and students, we learned the power of designing AI that enhances thinking rather than replaces it. Our research revealed major pain points (overreliance on AI, difficulty structuring ideas, and weakened critical thinking) which directly shaped Pebbl’s features.

What's next for Pebbl

We’re evolving Pebbl to go beyond just a mobile app. We have a roadmap for Pebbl where we want to introduce more features, mainly a citation feature, which aligns with our values and is ethical. Furthermore, we want to add integration with google docs, notion and obsidian, so students can continue to use Pebbl in their preferred workspace, and finally we want to create a cross platform web app which syncs with the app, allowing the users to edit their essays and various things across different devices.