Study Focus Redirector
A webcam focus monitor that watches your head and posture while you study, and when you keep drifting off it opens the McDonald's careers page for you.
The problem
Focus timers cannot tell whether you are actually working. They count minutes while you scroll your phone under the desk.
How I approached it
Face landmarks give head yaw and pitch, pose landmarks give torso lean, and both run through median smoothing before a state machine decides whether you are focused. It calibrates against your own neutral posture for five seconds first, so it measures drift from how you actually sit rather than from an average person.
The outcome
A study tool with genuine stakes, and a punchline that makes people actually keep it running.
Camera: this runs entirely in your browser. No video is uploaded or stored.