Interesting take on analog clock..

[Nicholas Stock]

https://www.kickstarter.com/projects/tungstencustoms/nixie-radian-analog-wall-clock

A bit pricey, but a nice use of IN9 tubes.....bit pricey though and those tubes can be a right pain in the proverbial when the glow decides it wants to leave the base of the tube....

Nick

[Alex]

Damnit I have wanted to do almost that exact design for years now. Teach me to get my finger out next time! Nicely done, and a surprisingly compact PCB. 

[gregebert]

Don't feel bad, Alex. I did some brief experimenting with IN-9 tubes and found them to be non-linear, if not downright irrational, and consume gobs of current considering how little light they produce.

I used individual NE-2H bulbs for the hands on my big clock. Lots of them....306 to be exact. Which also means 306 resistors, etc. Glad I did it that way because it's been working great for a few years now.

[Jeremy Medow]

Jeremy here (the creator of this clock).  I wanted to quickly address this:

- You're definitely right about gobs of current.  The tubes take around 12mA (at 140v striking voltage) to be fully lit.  The power supply I put in this thing puts out around 50mA tops (it has to fit inside the clock and not get too hot...), so all of the animations, etc. have to keep to that constraint.

- As for the non-linearity, the clock uses op-amp buffered npn current sinks for each of the digits to control the current quite tightly.  The glow length / current for the tubes, while not perfectly linear, is certainly close enough that you can't notice in an application such as this.

Let me know if you have any other questions about the operation of the clock - I'm happy to answer them!

Jeremy

[Nicholas Stock]

Quick question for you Jeremy if I may? Why IN9's over the IN13 tubes?

Lovely looking clock btw.

Nick

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[Jeremy Medow]

Hi Nick,

The IN-9 tubes are easier and cheaper to source in quantity than the IN-13.  The IN-13 would otherwise be easier (much less current at the very least).

Jeremy

[Alex]

I doubt IN-13s would suit this too well as they are quite a bit dimmer than IN-9s (hence the lower consumption and higher sensitivity)...

I suspect a couple of us on here may be interested in bare / populated PCBs if you are willing to sell them solo, as stockpiles of IN-9 tubes are quite common (at least around here!). 

My thoughts on powering a IN-9 field of tubes was going to center around a 115vac 50Hz isolating transformer and bridge rectifier (with very little smoothing for the tube supply) as that would give isolation and lots of current - the ripple also helping peg the tube at the right end...

- Alex

[Jeremy Medow]

Hey Alex - sorry, just saw this.

I thought about using the 115v as well (the fact that you could just 1:1 rectify is tempting) but for something that I'm placing in people's homes I didn't want a direct mains connection.

I would definitely be willing to sell the boards, not sure yet on price.  I still need to see whether I'm going to reflow them in-house or outsource it.  Shoot me an email (Jer...@TungstenCustoms.com) and we can chat about it.

Jeremy