This guide updates the Nixe tube from steam-punk to cyber-punk with LEDs and acrylic sheets. From Make:
The working principle of the Nixie replica is simple, but effective: Ten transparent plates made out of extruded acrylic sheet (polymethyl methacrylate or PMMA, also known as Lucite, perspex, or plexiglass) are engraved with the numerals 0 to 9. Stacked on top of one another, each plate is illuminated from the edge using multicolor LEDs. Due to the internal refraction of light within the acrylic plate, only the numeral that’s selected will actually light up, while the plates’ surfaces, and all the other numerals in the stack, will remain transparent and colorless.
We didn’t come up with this idea — we’ve seen it demonstrated at Maker Faires in the U.S. and Europe. Connor Nishijima, a maker in Utah, coined the name “Lixie” for his projects, inspiring many other makers.
Building an LED Nixie
The light from the LEDs on the circuit board shines into the tabs on the acrylic plate, which is engraved with a numeral. The foam mask on the board prevents the light from radiating sideways and straying into adjacent plates.Because the light enters the acrylic from the edge, total internal reflection occurs, and the acrylic behaves like a light pipe. The light’s path is broken only at the engraved lines (and at the edges of the plate) so that only these spots light up — and the digit shines.
