Calibration Display for NASA (2019) | Hacker News Reader

Calibration Display for NASA (2019)

daliborfarny.com

45 pointsomnibrain14 comments

I don't think it's an April Fools.

- They have a tiny GPS disciplined timing source by Brandywine Communications sitting next to the display. Brandywine supply very precise timing gadgets.

- They're in Czechia but the box is powered by 110V.

- The camera shooting the sole Nixie tube is a Photron by the looks of it.

- There's a video :) https://www.youtube.com/watch?v=TK3E55fytC0

- There's a picture posted by a NASA employee: https://www.facebook.com/photo.php?fbid=5110589098977129&set...

A slight tangent - is there any reason filament LEDs couldn't be fashioned into a Nixie Tube style number form? That seems like it might have the same nicely curved aesthetic but be easier to manufacture.

I'd assumed there would be some from the wonders of Shenzhen, but googling it seems not yet.

I'm curious about the Uncertainty gauge and what measurement drives it.

Interesting read, I'm surprised these tubes are so fast considering my one remaining filament bulb always takes a few seconds to warm up after being switched on. Do these use a different filament type?

I think the filament stays on and you switch what cathode is being used.

edit, I just read the wikipedia page on nixie tubes, there is no filament, despite looking like one it is not a thermionic vacuum tube. it is a cold cathode gas discharge lamp. so one anode with many switched cathodes.

Nixies don't emit light by heating, it's closer to neon tube

That clears things up, although I'm curious now why a VFD wouldn't be better

I think the answer is that they are making Nixie tubes:

https://www.daliborfarny.com/project/custom-nixie-tube-for-k...

https://www.youtube.com/watch?v=1nHkhJ52iA4

Obvious choice would not be VFDs or nixies but plain LEDs I'd imagine.

I don't get it, LEDs can be trivially modulated to MHz, why nixies? April fool?

I would imagine having a couple of FPGAs, toggling 7 segment LED displays can easily do the same thing.

Can they actually be turned on/off to a brightness useful for displaying time? Modulating in a way useful to transmit data is different than a display useful for a high speed camera.

Modulating a LED at a high depth will certainly have the required visual effect, as the frequency response curves found in literature are practically flat from DC to tens of MHz. For obvious reason, most people are interested only in data communication applicantions. No one bothers to try doesn't mean we can't resonably expect it will work.

As we all know, modern LEDs (or even semiconductor lasers), the achievable brightness is very high.

Besides, I would be very surprised that such a modern high speed camera system doesn't come with triggering inputs that allows trivial digital generation of timestamps.

Steins Gate clock

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