This headLamp consists of —about 300 LED’s soldered into a metal colander and are “wired to a circuit and controlled by the computer parallel port”. The iTunes plugin is written to accept sample data from iTunes when a song is playing, which takes the form of an integer between 0 and 128. The plugin operates under the assumption that a rhythmic beat is likely to send a higher value, around 120. If a sample value over 120 is sent, the plugin changes the lamp’s state based on preprogramed patterns like rotations, buildups, etc.

Source:→ MAKE | TecheBlog