<< 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 -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/2XG34tGIjpUJ. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
