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AI & Computer Vision

Drawzy AI / MobAI Hackathon

Hackathon drawing-game prototype where the mobile app sends sketches to a FastAPI backend for object prediction and round scoring.

PrototypeSource availableHackathon AI game backend / 2025

Problem

A drawing game needs fast sketch recognition and scoring that reflects time and prediction quality.

Solution

Build two FastAPI routes: one decodes base64 sketches, preprocesses them into 28x28 grayscale inputs, and calls a CNN; the other builds a 61-value observation and calls a PPO model.

Key Features

FastAPI app with routed sketch prediction and score endpoints
Base64 sketch decoding from the Flutter canvas export flow
Image preprocessing pipeline: grayscale conversion, drawing-area crop, aspect-preserving resize, and 28x28 padding
CNN sketch guess model trained on a Quick, Draw-style class subset with top prediction output
Gymnasium environment and PPO scoring model using timing, similarity sequence, and previous-score context
Flutter mobile surfaces for onboarding, mode selection, drawing, prediction, Firebase-backed sessions, and chat/game flow
Next.js landing repository that gives the prototype a product-facing presentation layer

Architecture Map

Mermaid
flowchart LR
  Player["Mobile player"] --> Mobile["Flutter Drawzy app"]
  Mobile --> Canvas["Sketch canvas and game modes"]
  Canvas --> GuessRoute["FastAPI predict sketch route"]
  GuessRoute --> ImagePrep["Decode base64, crop, resize, pad"]
  ImagePrep --> GuessModel["CNN sketch guess model"]
  GuessModel --> Predictions["Class label and top five guesses"]
  Mobile --> ScoreRoute["FastAPI score route"]
  ScoreRoute --> Observation["Similarity timeline plus previous score"]
  Observation --> ScoreModel["PPO scoring model"]
  ScoreModel --> RoundScore["Round score"]
  Mobile --> Firebase["Firebase app services"]
  Landing["Next.js landing page"] --> Mobile

Drawzy AI Screenshots

4 views
Guess-model training curves from the AI backend for the sketch classifier.
Mobile splash/brand screen from the Flutter app, giving the AI backend a visible product context.
Mode-selection screen for offline, online, and multiplayer drawing game flows.
Onboarding visual from the mobile repo, showing the prototype as a complete app experience.