Custom Nixies Perform When Cranked Up To 100,000 Hertz

With the popularity of Nixie clocks, we’d be forgiven for thinking that the glowing tubes are only good for applications with a stately pace of change. But we forget that before they became the must-have hobbyist accessory, Nixies were used in all kinds of scientific instruments, from frequency counters to precision multimeters. In such applications, update rates in the hundreds or thousands of Hertz aren’t uncommon, and the humble Nixie handled display refreshes with ease.

But what about refreshing a Nixie at 100 kHz? That was the question put to artisanal Nixie maker [Dalibor Farný] by a client who wanted a timer to calibrate high-speed cameras. It was a feat that [Dalibor] wasn’t sure his custom-made tubes could handle. The video below shows his efforts to find out.

If you ever wanted to know about the physics of gas-discharge displays like the Nixie, the fifteen minutes starting at about 5:13 will give you everything you need. That basic problem boils down to the half-life of excited neon, or how long it takes for half the population of excited molecules to return to the ground state. That, in turn, dictates how long a given cathode will continue to visibly glow after it’s turned off, which determines how many digits will appear illuminated at once.

To answer that, they engaged a company in Prague with a camera capable of a mind-blowing 900,000 frames per second. Even though they found a significant afterglow period for each cathode, even at 100 kHz it’s clear which digit is the one that’s currently illuminated. They also looked at the startup of digits in a cold Nixie versus one that’s warmed up, leading to some fascinating footage at around 26:30.

We appreciate [Dalibor]’s attention to detail, not only in the craftsmanship of his custom tubes but in making sure they’re going to do their job. He recently did a failure analysis on some of his high-end clocks that showed the same care for his product and his brand.

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Multimeter Display Perked Up With Nixies, LEDs, And Neon Tubes

Just because something is newer than something else doesn’t automatically make it better. Of course the opposite is also true, but when it comes to displays on bench multimeters, a fancy LCD display is no guarantee of legibility. Take the Hewlett Packard HP 3478A multimeter; the stock transflective display with its 14-segment characters is so hard to read that people usually have to add a backlight to use it.

That wasn’t good enough for [cyclotronboy], though, who chose to completely replace the stock 3478A display with Nixie tubes. He noticed that with a little modification, six IN-17 tubes just fit in the window vacated by the LCD. He sniffed out the serial data stream going to the display with a collection of XOR gates and flip-flops, which let him write the code for a PIC18F4550. The finished display adds a trio of rectangular LEDs for the + and – indicators, and an HDLO-1414 four-character alphanumeric display to indicate units and the like. And the decimal points? Tiny neon bulbs. It already looks miles better than the stock display, and with the addition of a red filter, it should look even better.

If you’re stuck with a lame LCD multimeter but Nixies don’t quite do it for you, worry not – an LED conversion is possible too.

MIDI Controlled Neon

The people who make neon signs are a vibrant community with glass bending and high voltage electronics. There is a need, though, to sequence these neon signs, and it seems like MIDI is the way to do it. That’s what [david] is doing for his entry to the Hackaday Prize, and the results already look great.

The idea for this project is to transmit MIDI data to a controller that activates neon tubes accordingly. As for why [david] chose MIDI over DMX512 or some other protocol, the object here is to sync with music, and if you already have a drum machine sending MIDI out, you might as well just patch into that.

The build uses an Arduino Leonardo with a MIDI shield produced by Olimex. This shield is connected to a neon power supply that has control circuitry to quickly and easily turn neon signs on and off. The end result is a laptop (with the rest of the DJ software) sending a MIDI clock signal to an Akai drum machine. This drum machine outputs MIDI notes to the shield, which is currently set up to control three neon transformers.

The results look great, with flashing skulls synchronized with bleeps and bloops. This, of course, can be expanded to even more MIDI synced neon signs. You can check out a few videos of the build after the break.

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Pocket High Voltage Generator Becomes Great Test Tool

[The LED Artist] often found a need for a relatively high voltage (100 to 200 Volt) but low current DC power supply, and it turns out that a small HV generator that uses a single AA cell only took about an hour to make. The device ended up being a pretty handy tool for testing things like LED filaments (which have a forward voltage of over 60 V), or even neon and nixie tubes.

The device’s low current means that nixie and neon elements won’t light up very brightly, but they will light up enough to verify function and operation. [The LED Artist] reports that touching the output terminals of the generator only causes a slight tingling sensation.

Open-circuit voltage generated from a single AA cell is about 200 V, but that voltage drops rapidly under any kind of load. Even regular LEDs can be safely lit with the circuit, with less than a milliamp being supplied at the two to three volts at which most regular LEDs operate.

[The LED Artist] fit the device into a two-AA battery holder, with a single AA cell on one side and the circuit in the other, and says it’s one of the more useful tools they’ve ever made. LED filaments are fairly common nowadays, but if they intrigue you, don’t forget that [Mike Harrison] covered everything you need to know about experimenting with them.

Neon Lamps Make For The Coolest Of Nixie Clocks

Revisiting old projects is always fun and this Nixie Clock by [pa3fwm] is just a classic. Instead of using transistors or microcontrollers, it uses neon lamps to clock and drive the Nixie Displays. The neon lamps themselves are the logic elements. Seriously, this masterpiece just oozes geekiness.

Inspired by the book “Electronic Counting Circuits” by J.B. Dance(ZIP), published in 1967, we covered the initial build a few years back. The fundamental concept of operation is similar to that of Neon Ring Counters. [Luc Small] has a write-up explaining the construction of such a device and some math associated with it. In this project, [pa3fwm] uses modern day neons that you find in indicators, so his circuit is also updated to compensate for the smaller difference in striking and maintaining voltages.

The original project was done in 2007 and has since undergone a few upgrades. [Pa3fwm] has modified the construction to make it wall mounted. Even though it’s not a precise timekeeper, the project itself is a keeper from its time. Check out the video below for a demonstration.

Feel inspired yet? Take a peek at the White Rabbit Nixie Clock and you are looking for a low voltage solution to powering Nixies then check out the 5-volt Nixie Power supply.

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A Relay Calculator With DIY Neon Displays, Just Because

This looks like one of those projects that started out as a glimmer of an idea and led down a rabbit hole. But it’s a pretty cool rabbit hole that leads to homebrew neon seven-segment displays on a calculator with relay logic.

It’s a little thin on documentation so far, but that’s because [Mark Miller]’s build is one of those just-for-the-fun-of-it things. He started with a bag full of NE-2 tubes and the realization that a 3D-printed frame would let him create his own seven-segment displays. The frames have a slot for each segment, with a lamp and current limiting resistor tucked behind it; with leads brought out to pins and some epoxy potting, these displays would be hard to tell from a large LED seven-segment. Rolling your own displays has the benefit of being able to extend the character set, which [Mark] did with plus-minus and equal sign modules. All of these went together into a two-banger calculator — addition and subtraction only so far — executed in relays and vacuum tubes. Version 2.0 of the calculator regressed to all-relay logic, which must sound great.

We heartily regret the lack of a satisfyingly clicky video, but we’ll give it a pass since this is so cool. We’ll be watching for more on this project, but in the meantime, if you still need to get your click on, this electromechanical BCD counter should help.

Relive Radio Shack’s Glory Days By Getting Goofy

The Golden Age of Radio Shack was probably sometime in the mid-1970s, a time when you could just pop into the local store and pay 49 cents for the resistors you needed to complete a project. Radio Shack was the place to go for everything from hi-fi systems to CB radios, and for many of us, being inside one was very much a kid in a candy store scenario.

That’s not to say that Radio Shack was perfect, but one thing it did very well was the education and grooming of the next generation of electronics hobbyists, primarily through their “Science Fair” brand. Some of us will recall the P-Box kits from that line, complete projects with all the parts and instructions in a plastic box with a perfboard top. These kits were endlessly entertaining and educational, and now [NetZener] has recreated the classic neon “Goofy Light” P-Box project.

As it was back in the day, the Goofy Light is almost entirely useless except for learning about DC-DC converters, multivibrators, RC timing circuits, and the weird world of negative resistance. But by using the original Science Fair instructions, compiling a BOM that can be filled from Mouser or Digikey, and making up a reasonable facsimile of the original P-Box chassis, [NetZener] has done a service to anyone looking for a little dose of nostalgia.

It would be interesting if someone brought back the P-Box experience as a commercial venture, offering a range of kits with circuits like the originals. If that happens, maybe some of the offerings will be based on that other classic from Radio Shack’s heyday.

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