Make: Technology on Your Time Volume 25

ELECTRONICS: FUN AND FUNDAMENTALS

By Charles Platt

A Trippy Crystal Nightlight

Create any color, using 3 LEDs and the trick of pulse-width modulation.

On a shelf above my bed stands something highly unusual: a giant, translucent, crystalline chunk of salt (Figure A), given to me by a friend who imports gemstones from Pakistan.

Photography and diagrams by Charles Platt

Fig. A: By day, an 8" crystalline chunk of salt.

The salt was drilled with a ...