Point a projector and a webcam at any wall. Draw with a laser pointer. The projector paints your strokes — glowing neon, dripping ink, spinning in 3D.
Inspired by this video — laser tagging buildings with a projector, done years ago and still magical. Read the backstory ↓
No projector needed for this one — your mouse (or finger) is the laser. Pick a brush, flip on a mode, or play tic-tac-toe against the computer by drawing an X in a cell.
Everything runs in the browser — no install, no native app.
Connect a projector as a second screen and point a webcam at the projected area. Open the control window and the projector window (press F for fullscreen).
One click flashes markers into the corners of the projection; the camera finds them and computes the camera→projector mapping. Then wave the laser for 4 seconds so the detector learns its brightness and colour.
Every frame the camera finds the laser dot, maps it onto the projector, and the projector renders the stroke — right where you pointed. Hold the laser in the ☰ corner to open an on-wall menu.
The inspiration came from mzeltner (Michael Zeltner) and oneup (Florian Hufsky) of Graffiti Research Lab Vienna, who around 2007 built their own laser marker and tagged buildings across Vienna with it. They in turn were inspired by the original Graffiti Research Lab in New York and its L.A.S.E.R. Tag project — the same idea: a camera, a projector, and a laser pointer as the pen, writ large on the side of a building.
Here's Bre Pettis talking with Michi about Laser Tag in Vienna:
This project is a from-scratch reimplementation of that idea for the browser — no Processing, no install, just a laptop, a webcam and a projector.
A laptop with Chrome, a projector (any HDMI projector works — it's just a second screen), a webcam that can see the projected area (the built-in one is fine), and a laser pointer. Green shows up best on camera.
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