Things I've built

A reaction-speed puzzle game where you tilt your phone to move a marker across a 3×3 grid to the target cell. The timer shortens each round, keeping pressure constant. Designed from the ground up for equal access: TTS announces your position and target each round, a metronome shifts from 60 to 180 BPM as time runs out, and haptic feedback marks every move and collision — so the game is fully playable without looking at the screen. Includes a real-time Supabase global leaderboard and a 3-step interactive onboarding tutorial.

An Android app for watching only the YouTube videos you picked, in your own sequence. Paste youtube.com/watch, youtu.be, Shorts, or embed URLs to add videos to a local playlist, then ChainPlay automatically moves to the next item when one ends. It uses the official YouTube player without login and supports previous/next controls, ▲▼ reordering, deleting videos, local persistence, and Korean/English auto-detection.

An Android music player that brings the 1980s cassette tape experience to a modern phone. Instead of instant skipping, you have to press and hold FF to move to the next track. Each cassette has Side A and Side B with a 30-minute limit per side, and tape noise plays between tracks. It uses local music files only, with no internet and no algorithm, so the experience stays focused on the songs you chose.

A personal developer blog documenting the journey back into development. The publishing workflow is fully automated: push a Markdown file to GitHub, and GitHub Actions publishes it on the scheduled date. Built with Next.js App Router to serve Korean and English routes separately, with SEO metadata, sitemap, and robots configured. This portfolio page is part of the same blog.

Built to eliminate the awkward WiFi password exchange at cafés, restaurants, and small businesses. Enter your SSID and password, get a QR code instantly. Print it as a card, stick it on the wall — guests scan with their camera and connect. Supports Korean, English, Chinese, and German.