Science Meets Style In This Cathode Tube Watch 190
scope-n-SHOUT writes "The Nixie Watch displays the time on nixie tubes, a cold-cathode tube filled with neon, a little mercury and argon at a small fraction of atmospheric pressure. Nixies were used in many early electronic desktop calculators, including the first: the vacuum tube-based Sumlock-Comptometer Anita Mk VII in 1961. This two-digit wristwatch is designed for everyday use, being water-resistant and rugged, not to mention looking really retro-future cool. The watch requires no button pushing to operate - it shows the hours, minutes and seconds in sequence at the flick of the wrist. For the hardcore code tweaker, a programming adapter allows the GPL'd PIC firmware running the watch to be hacked up at will. The Nixie Watch is being sold in very limited edition, with each piece individually numbered and engraved."
Not the only one (Score:5, Informative)
Re:Why a watch? (Score:5, Informative)
Something like one of these [amug.org] or these [electricstuff.co.uk]?
Science Meets Style (Score:4, Informative)
Seriously people.. this does not look cool, neat, retro, funky or any thing other than an ugly lump on the end of an appendage.
Much cooler version (Score:3, Informative)
No, its different. (Score:4, Informative)
Its basically a glow discharge tube like you can find them as gadgets sometimes (like a hearth, or a number or so glowing). The glow is around the kathode, which can be formed however you want.
So this tubes have 10 different kathodes in one tube, sorted by visibility (to but the "big" shapes back as to not hinder the view to other ones). All in all, you can see that they are in different planes (about 5-8mm or so, which makes neat effects for a frequency counter (as the digit seems to jump rapidly, seemingly randomly back and forth in 3d-space)).
It's not that simple... (Score:5, Informative)
...power is a problem... (Score:3, Informative)
Re:Why a watch? (Score:5, Informative)
In a Nixie tube, the cathode wires are shaped into numbers {or letters, or symbols} and each one is brought out to a separate terminal pin. The anode is a fine wire mesh grille in front of the cathodes. This is connected, through a ballast resistor {to limit the current} to a positive supply of several tens of volts DC {dependent upon the size of the tube}. When one of the cathodes is connected to ground, the gas ionises and a visible glow is given off around the cathode. The smaller the resistor, the bigger the current, and the further the glowing region extends {and the shorter the overall lifetime of the tube, since some material is transferred }; the general aim is to get a strong enough glow around the active wire so the whole digit is visible. Note that if a switched-mode power supply is being used to generate the high voltage, it will most probably already have a high enough output impedance so as not to need a ballast resistor.
The cathodes can be driven by ordinary, open-collector NPN transistors but they must be selected carefully: the collector-base junction must have a sufficiently high breakdown voltage to withstand the display drive voltage. Otherwise the C-B junction will behave like a Zener diode, essentially dropping a constant voltage irrespective of how much current is flowing through it; and once a digit has been lit, it won't extinguish until the anode supply is interrupted. It won't actually fail catastrophically due to the ballast resistance limiting the current; but it probably is not what you want anyway. If the anode supply is switched-mode, and the output capacitor is small enough that this afterglow can discharge it completely, you might just be able to get away with using under-rated transistors to switch the cathodes; but this is not ideal since the anode supply will always be dying {not just in the afterglow while the transistor is staying on} and the display will flicker.
more nixie clocks from my watchmaker (Score:3, Informative)
Re:Better site, and cool photo: (Score:4, Informative)
Re:Retro-future cool (Score:2, Informative)