Minneapolis maker Michael Krumpus, who also sells the EZ-Expander in the Maker’s Market, created this lovely mood lamp made out of LEDs, an Arduino Duemilanove, and glass vials he bought from the Twin Cities’ legendary Ax-Man surplus store.

This is a mood lamp I build using 16 LEDs of different colors and small glass vials. The square bottoms of the vials look a lot like glass block, and the glass diffuses and scatters the light in beautiful ways. The software shows random patterns of light and the brightness of each LED can vary — they aren’t simply “on” or “off”.

The Arduino code is pretty complex because it implements PWM (pulse-width modulation) for all 16 LEDs. The Arduino board only has 5 PWM-capable pins, so providing PWM for all 16 pins is accomplished purely in the code. The lamp randomly displays different lighting patterns and can be really mesmerizing.