This is seriously cool and well worth 2 minutes of your time. Don’t like the knobs and sliders on your synthesizer? Can’t afford a new control pad? Draw yourself a new one. Billy Keyes created SynthSketch to do just that. All you need is a sheet of paper and a Sharpie (or a knockoff – the Shoopie). OK, there are some technical programmy bits too.

The details for the doubters and techy curious among you (see a fuller explanation on his site):

SketchSynth is built on openFrameworks and makes heavy use of Kyle McDonald’s excellent ofxCv addon. A standard webcam looks down at the paper and detects both controls and hands… You can interact with any detected controls. While an infrared camera is ideal to prevent interference from the projection, I had to make due with a standard color camera when my IR conversion didn’t go as planned.

Controls are detected by finding contours (blobs) in an edge-detected version of the image… Hands are detected by subtracting the constant background and looking for blobs. The contour of the largest blob is smooth and the finger is assumed to be the point farthest away from the center of the blob… The camera and projector are aligned by clicking on the four corners of a projected rectangle (as seen by the camera) when the program starts up.

The design allows for momentary buttons, toggle switches and sliders. Keyes also talks of his childhood love of control panels which appeals to me. Knobs, switches, buttons; it’s so hard to resist playing with them to see what will happen, so long as you aren’t in a top secret laboratory in which case some self control should be exercised.

- via Eclectica