Open Source Russian Vacuum Fluorescent Tube Clock

ptorrone writes "Hacker extraordinaire Ladyada (whose open source hardware projects we have discussed before) has just published a complete how-to, with design document, on making your own open source Russian vacuum fluorescent clock. The vacuum fluorescent tubes aren't as dangerous as (high-voltage) Nixie tubes, and there seem to be more of them available in the world. If you're not interested in building a clock from scratch, you can also pick up a kit version. All the schematics, source code, and files are available on the project's page."

It has software?

[Anonymous Coward]

I've built Nixie clocks, and there shouldn't be any software involved at all. You can get clock ICs cheaply enough, a microprocessor is overkill for this kind of project.

Re:Cute, but how about this.

[John Pfeiffer]

I don't know, man. The old IV-18 tubes are really wicked looking. You have a cylindrical glass vacuum tube, and inside it is a slab of glass with 7-segment digit phosphors, shiny silver traces, and extremely tiny, thin hexagonal grids infront of each digit. So, it basically looks like a glowing blue digital readout 'suspended' in a thin glass envelope.

There's also the IV-27 which is larger and 13 digits instead of 8, and the IV-21 (I think it's 21) which is a tiny version of the IV-18.

0.002% accuracy?

[Arancaytar]

I hope that is the error, not the accuracy. :P

For a self-built clock, losing 1.728 seconds a day isn't too bad. But it's not that great either...

Re:Quite neat, actually.

[bitrex]

They're not rare in Soviet Russia! Joking aside, these VFDs are not that rare. Like some kind of state-sponsored labor monster run amuck, these (and all kinds of other vacuum tubes) were produced by the trainload during the heyday of the Cold War. They can now be picked up for a few dollars on eBay from sellers in Russia and the former Soviet republics. Of course the US produced its fair share of tubes as well, but the vacuum tube era seems to have lasted much longer in Eastern Europe than here (particularly in military applications), and lots of the common NOS tubes in the US have been used up in guitar and stereo amps. In the strange world of vintage vacuum electronics it is often the more exotic looking items covered in Cyrillic that are cheap and cheerful, and the US and UK parts that are rare and coveted.

It would be interesting to know what product these VFD tubes were initially intended for; maybe they were used in calculators given the number of digits. The US pretty much jumped directly from Nixies and Numitrons right to LEDs and LCDs, but I'm betting that in Eastern Europe the adoption of LED technology was more slow and there needed to be a display technology to fill the gap. I think my suspicions may be correct given this eBay aucion [ebay.com] where a Russian manufactured VFD clock is for sale - the description says it supposedly was manufactured in 1982 when a similar product in the US would be LED for sure.

Re:Quite neat, actually.

[PhunkySchtuff]

Have a look at Ponoko [ponoko.com] - they're great for making one-off items, like this case, from all sorts of laser-cut materials. I'm not affiliated with Ponoko, just a happy customer. Looking at the design of the case, if it wasn't laser-cut, it should have been - a case like that would be trivial to get sorted out with the precision of laser cutting...

Re:Oh come on, get a clue.

[Thoughts from Englan]

Fair point but the beauty of using a microcontroler is that you can reconfigure the system to specific needs without having to redesign the hardware every time. This is pretty much what microprocessors were intended for until various people thought "Hey I can make a general purpose machine out of these"

Re:A few glitches in the vodka

[ladyada]

the PWM is hardware controlled and there's a WDT its as reliable as any 'off the shelf' chip...even 555's latch up if set up wrong ;)

Re:It has software?

[ladyada]

if you read the design document, schematic and source you'll see theres a lot more in there than just a counter. theres day calculator, date, alarm, low power mode, RTC, HV boost, menu system with configuration, etc etc. a $2.50 microprocessor isnt overkill when you consider its doing -everything- except drive the HV VFD.

Re:Low-power RTC

[ladyada]

Yup! If you look at the schematics or design document you will see how this works - its described in detail there but basically: If power is unplugged, the microcontroller kills the display and runs at 50uA off of a coin cell for a couple of weeks until power is restored. the low power RTC is used when theres a blackout or the clock is moved, etc. Its a big pet peeve, all clocks should do this!

Re:A few glitches in the vodka

[ladyada]

it is firmware controlled but its set once, its not like an interrupt has to go off at the exact right time. AVRs are pretty good about not freaking out as long as you have BOD set and a WDT (which it does). also, to make the clock display brightness adjustable you cant just use an RC oscillator...how would you set the PWM duty cycle? could it *possibly* screw up? sure. just like logic chips sometimes die or glitch. but its not medical equipment, theres no interlocks, its a DIY desk clock kit in a plastic enclosure.

Re:It has software?

[digitalunity]

Open Source has grown beyond just a description of software, it's an ideology too.

And indeed, if we were talking about Verilog or VHDL, indeed, the "schematic" might just be little different from source.