Numitron in a vehicle?

[Adam Jacobs]

I know that a lot of people have experience with putting Nixie clocks in
cars. It sounds like nixies are not well suited to the vibration.
How about numitrons? Has anyone done a car clock with numitrons?

-Adam

[jb-electronics]

Numitrons are much more sensitive than Nixie tubes due to the filament
wire, I would not recommend it.

Jens

[Per Jensen]

On 19/04/2012, at 18.47, jb-electronics wrote:

Numitrons are much more sensitive than Nixie tubes due to the filament wire, I would not recommend it.

Jens

Why are they used in highly-dependable aircraft instruments ?

If the filament voltage is low they're quite durable i'm told...

// Per.

[Tidak Ada]

I used long time a 3015F minitron incandecsent display without any trouble
in a Citroën 2CV as tachometer display.
Advantage is the high contrast and readability (no paralax) in comparison
with nixies. This is also the main reason incandescent displays as Minitron
and Numitron are used in airborne displays.

Jens

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[Adam Jacobs]

Ah, interesting!
I will maybe give it a shot then. The little IV-16 numitrons are very
tiny, they seem like the perfect size for some kind of vehicle display.

-Adam

On 4/19/2012 12:45 PM, Tidak Ada wrote:
> I used long time a 3015F minitron incandecsent display without any trouble

> in a Citro�n 2CV as tachometer display.

[Mark Moulding]

<< I know that a lot of people have experience with putting Nixie clocks in
cars. It sounds like nixies are not well suited to the vibration.
How about numitrons? Has anyone done a car clock with numitrons? >>

and

<<Numitrons are much more sensitive than Nixie tubes due to the filament
wire, I would not recommend it. >>

Surprisingly, even though they have filaments, Numitrons are very robust display devices.  US-made products (such as the RCA DR2000 types) had a rated life of 100,000 hours - the same as LEDs!  The RCA data sheets give very detailed vibrational test information (with numbers like "peak impact during operation=200g", "continuous vibration 20g max from 60-500Hz", etc.  In other words, these things were made for a rough life - a dashboard instrument is no problem.

From what I can glean from the Russian IV-9 and IV-16 data sheets (I don't speak or read Russian), they're rated at 10,000 hours - still a pretty long lifespan.  I've used these tubes quite a bit (including in an off-road vehicular application [Burning Man]), and have never had one fail (except for the one that got hit by a tent stake).

The Numitrons are incredibly easy to drive, too.  Many micros can drive them directly from their output pins, and I've had good luck driving them directly from 74HC595 shift registers, using PWM on the _OE_ input to adjust the brightness.  Like Nixies, they give a wonderfully nice warm glow, and they a bright enough for daylight readability when operated at rated voltage.  (I usually run them [or PWM them] to about 50-75% of rated voltage, both for the nice orange color, and for longer life.)

If you really want to drive them right, the segments that are "off" shouldn't be really off, but rather energized to just below the level of visibility.  This greatly lessens the thermal shock when the segments are turned on, and for direct-drive microprocessor outputs also keeps the peak current within the ratings of the chip (except at initial power-up).  I have a "smart socket" that I use quite a bit that has a single low-pin-count 8051 derivative (AT89C2051) that does all this, and can be daisy-chained to any length serially.  A single serial output pin (as from a Basic Stamp, for example) can then drive the entire display set.  I've posted all the design files (PCB, schematic, and C code) on the SmartSockets Yahoo group...
~~
Mark Moulding

[Terry Kennedy]

On Apr 25, 1:37 pm, Mark Moulding <urros...@att.net> wrote:
> Surprisingly, even though they have filaments, Numitrons are very robust
> display devices.  US-made products (such as the RCA DR2000 types) had a
> rated life of 100,000 hours - the same as LEDs!  The RCA data sheets give
> very detailed vibrational test information (with numbers like "peak impact
> during operation=200g", "continuous vibration 20g max from 60-500Hz", etc.
> In other words, these things were made for a rough life - a dashboard
> instrument is no problem.

The local no-name cheap gas station / pseudo-truckstop here still has
Numitrons on their diesel fuel pumps. The gas pumps were replaced with
back-lit LCD units some years ago. The diesel Numitrons don't seem to
be damaged by being hit, nor from staying lit with all 0's all night
long.