I've mentioned this watch in a couple of other threads, but as it is rather unusual and there seems to be a bit of interest thought it worth one of its own.
I really like vintage electronic displays, and have a particular fondness for the warm glow of Nixie tubes. I've built a couple of the excellent Nixie tube clock kits from PV Electronics and, unsurprisingly, have an early '70s Nixie display calculator.
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I've long coveted a Nixie tube watch, however the original circular model from Cathode Corner (made famous by Steve Wozniak) was huge at 55mm diameter and 20mm thick, mainly to accommodate the large single-use 750mA-hour CR2 lithium battery.
Woz can get away with that, but the mad scientist type creator, David Forbes, has long been refining a rectangular symmetrical model (wisely in collaboration with a creative brand designer) featuring a rechargeable battery and slightly more modest dimensions aimed at slightly more modestly dimensioned customers. This year he began producing the new version which is housed in an anodised aluminium case measuring 48mm wide by 53mm tall, and only 16mm thick. Still pretty big but that's quite a feat given the electronics it needs to contain.
Charging the LiPo battery is via a discreet USB socket and to extend time between charges a programmable accelerometer is used to detect when the watch is held at the correct angle for viewing. It runs for 2-3 weeks on a single charge.
It is very accurate; the quartz crystal timing circuit has a variable capacitor to allow adjustment of the operating frequency to within a few parts per million and it has been adjusted to +/-1 PPM at 25ºC.
The Nixie display tubes require about 180V to light up the neon gas and about 140V to sustain the orange plasma glow. The voltage is provided by a DC-DC converter chip, a step-up transformer and a voltage tripler circuit.
There is a ream of technical information including the programming source code on the Cathode Corner website for anybody interested, so I will not elaborate further here.
On the practical side, it takes standard 20mm straps and because these drop directly from the underside of the watch it snugly fits my 6⅞" wrist despite the large size. The aluminium cover can be easily changed for one of the other colours available; I like the black but might buy a green one for variety as I like the combination of green and orange Nixie tube glow (as in the clock above).
As there is only room for two of the 40 year-old 14mm NL-5870 tubes, the display cycles from hours to minutes and then running seconds when turned to the preset angle.
Here are the photographs that most of you will have already scrolled straight down to :smug:.
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It is perfectly visible in daylight but looks especially effective in low light conditions, and will probably be worn indoors only in any case.
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And here is a .gif, showing the accelerometer and changing display in action.
https://media.giphy.com/media/3o7TKH...gZFK/giphy.gif
