Air Draw
Write in the air with your finger. A webcam drawing app that tracks your fingertip with MediaPipe Hands and paints onto a canvas over the live video feed.
Hold up your index finger to draw, raise index and middle together to hover, and show an open palm to clear the board. A palette, brush size slider, emoji brushes, and a Save PNG button live in a toolbar at the bottom of the screen. There is no build step: it is a static app that loads MediaPipe from a CDN.
The interesting part is making hand tracking feel like a pen. A finger-extended test compares fingertip and knuckle positions normalised by palm size so it works at any distance from the camera. Gesture hysteresis keeps strokes unbroken by requiring several consecutive non-draw frames before lifting the pen, short tracker dropouts are tolerated, and an exponential moving average on the fingertip position removes jitter.