Wednesday, October 5, 2011

Vacuum Tube Hacks

Hi all,

Here's a collection of mini-hacks I've been collecting for a while. The theme: vacuum tubes.

Q: Alec, why are vacuum tubes awesome?
A: Get out. I refuse to answer stupid questions.

Exhibit 1: Vacuum Tube Nightlight

This is a pretty simple one. Vacuum tubes are basically light bulbs with a bunch of extra junk inside; they aren't designed to throw light but they do glow nicely. If you drive them at a higher voltage than they're designed for, they'll glow more brightly.

This is a 6V tube, driven at 12V, mounted directly to a slightly modified wall wart (read: warranty brutally voided with a drill). A little cosmetic work, an Automatic Turquoise International logo, and it's a handy night light.

Exhibit 2: Vacuum Tube Candle

Similar, but different.

The esthetics of this particular tube came out really nicely -- a flame-like glow with a low light.

Exhibit 3: Vacuum Tube Memory Key

This one is kind of a technological joke, accomplished thanks to the gentle application of a Dremel diamond cut-off blade and some dead-bug magic.

This is a working USB memory key mounted inside a vacuum tube like a ship in a bottle. If you take the plastic shell off a USB memory key you'll see a little sliver of circuit board with a few semiconductors mounted on it -- that's what I mounted inside the tube.

A semiconductor like a flash memory is basically a tremendous number of switching elements -- transistors -- packed into a tiny space at incredible density. Before semiconductors were invented, vacuum tubes were their predecessors. This is why the first computers were so enormous and power-hungry. Hence the joke: packing millions of switches inside the carcass of one. And I kind of thought the internals looked similar too.

Not pictured: the USB jack at the other end. (I mounted it onto a hobbyist-style wood block, but can't find a photo of that at the moment.)


  1. Nice job!

    I have a few of these about as well, including some very old tubes lit up at my desk at work. An old 200W radio transmitter tube lights up my desk at home when I dare plug it in. It draws 6A of filament current.

  2. Yikes, 6A -- I hope that's not at 120V...! I'll bet it's a decent space heater.

  3. I forgot to mention -- thanks to Free Geek for the wall warts and USB hardware.

  4. by the way is there anything free about free geek?

  5. EagleTeamExtreme -- see my comment just above yours.

  6. You should make a "steampunk Nixie Clock" with old tubes as part of the driver circuitry.

    Old tubes are nice for this, because they often glow blue when energised.
    With a simple UV filter this actually shows all the electron patterns within the tube, mere pictures do not do it justice.


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