Marquee Display Uses Six Dozen Surplus VFD Tubes to Great Effect

The quest to repurpose surplus parts into new and interesting displays never ends, it seems. And the bigger the display, the better, with extra points for using some really obscure part, like these surplus Russian vacuum-fluorescent tubes turned into a marquee display.

As [tonyp7] freely admits, this is a pet project that’s just for the fun of it, made possible by the flood of surplus parts on the market these days. The VFD tubes are IV-25s, Russian tubes that can be had by the fistful for a song from the usual sources. The seven small elements in the tube were intended to make bar graph displays like VU meters, but [tonyp7] ganged up twelve side by side to make 84-pixel displays. The custom driver board for each matrix needs three of the old SN75518 driver chips, in 40-pin DIPs no less. A 3D-printed bracket holds the tubes and the board for each module; it looks like a clock is the goal, with six modules ganged together. But the marquee display shown below is great too, and we look forward to seeing the finished project.

From faux-Nixies made with LEDs to flip-segment displays driven by relay logic to giant seven-segment LEDs that can be 3D-printed, we really like the trend to unique displays. What are you dreaming up?

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It’s a Nixie! It’s a VFD! No, It’s a Custom LED Display in a Tube

Like the look of Nixies but they just seem a little overdone? Or perhaps you just don’t want the hassles of a high-voltage power supply? Then maybe these faux-Nixie LED “tube” displays will find a way into your next clock build.

For his 2018 Hackaday Prize entry, [bobricius] decided that what the world needs is a Nixie that’s not a Nixie. To that end, each display is formed by seven surface-mount LEDs soldered to a seven-segment shaped PCB and slipped into a glass tube. The LEDs are in 4014 packages so they’re only 4 millimeters long, but what they lack in size they make up for in brightness. We’re not sure if it’s a trick of the camera, but the LEDs certainly seem to put off a bluish glow that’s reminiscent of vacuum-fluorescent displays — it’s like a Nixie and a VFD all rolled up in one package.  The current case, which hides the clock circuitry on the lower part of the PCB, is just plastic, but this would look spiffy in a fine wooden case.

Could this be another Nixie tube killer that never was? Perhaps, but wherever it ends up, we like the look of it, and we’re glad it’s one of the early Hackaday Prize entries. Have you got something to enter in the greatest hardware competition on Earth? If not, get cracking!

Quick and Dirty Driver Tips for Surplus VFDs

Sometimes it seems like eBay is the world’s junk bin, and we mean that in the best possible way. The variety of parts available for a pittance boggles the mind sometimes, especially when the parts were once ordered in massive quantities but have since gone obsolete. The urge to order parts like these in bulk can be overwhelming, and sooner or later, you’ll find yourself with a fistful of old stuff but no idea how to put it to use.

Case in point: the box of Russian surplus seven-segment vacuum fluorescent displays (VFDs) that [w_k_fay] had to figure out how to use. The result is a tutorial on quick and dirty VFD drivers that looks pretty handy. [w_k_fay] takes pains to point out that these are practical tips for putting surplus VFDs to work, as opposed to engineered solutions. He starts with tips on characterizing your surplus tubes in case you don’t have a pinout. A 1.5 V battery will suffice for the hot cathode, while a 9 V battery will turn on the segments. The VFDs can be treated much like a common cathode LED display, and a simple circuit driving the tube with a 4026 decade counter can be seen below. He also covers the challenges of driving VFDs from microcontrollers, and promises a full build of a frequency counter wherein the mysteries of multiplexing will be addressed.

Sounds like it’s time to stock up on those surplus VFDs and put them to work. For inspiration, take a look at this minimalist VFD clock, or perhaps mix VFDs with Nixies to satisfy your urge for all things glowy.

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Celebrate Display Diversity for a Circuit Circus Clock

There’s a lot to be said for nice, tidy projects where everything lines up and looks pretty. Seeing straight lines and pleasing proportions speaks to our obsessive-compulsive tendencies, and tends to soothe the mind and calm the spirit. But disorder is not without its charm, and mixing it up a little from time to time, such as with this mixed-media digital clock, can be a good idea.

Now, we know what you’re thinking — yet another Nixie clock. True, but that’s only half the story — or more accurately, one-sixth. There’s but a single Nixie in [Fuselage]’s circus-punk themed clock, used for the least significant digit in the hours part of the display. The other digits are displayed with four seven-segment devices — a Numitron, a vacuum fluorescent display, and an LED dot display — plus a real oddball, an old electromechanical display with individual slides for each character and a rear-screen projector. The RTC part of the project is standard Arduino fare, but as you can imagine the power supply needed for such a diversity of displays is pretty complex and has to provide everything from +5 to -270 volts. Each display needs its own driver, too, making this more of a zoo than a circus. The mixed up look just works with the circus theme, too. We’d really like more information on the projector display, though.

Looking for a real statement for your next clock build? Check out the rare as hens’ teeth NIMO tube.

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VFD Puts the Suck Back into Desoldering Station

A dedicated desoldering station is a fantastic tool if you’re in the business of harvesting components from old gear. Having heat and suction in a single tool is far more convenient than futzing with spring-loaded solder suckers or braid, but only as long as the suction in the desoldering tool has a little oomph behind it. So if the suction on your solder sucker is starting to suck, this simple VFD can help restore performance.

Luckily for [Mr. Carlson], his Hakko 470 desoldering station is equipped with an AC induction motor, so it’s a perfect candidate for a variable frequency drive to boost performance. He decided to build a simple VFD that boosts the frequency from 60-Hz mains to about 90-Hz, thereby jacking the motor speed up by 50%. The VFD is just a TL494 PWM chip gating the primary coil of a power transformer through a MOSFET. Duty cycle and frequency are set by trimmers, and the whole thing is housed in an old chassis attached to the Hakko via an anachronistic socket and plug from the vacuum tube days. That’s a nice touch, though, because the Hakko can be returned to stock operation by a simple bridging plug, and the video below shows the marked difference in motor speed both with and without the VFD plugged in.

We’ve marveled at [Mr. Carlson]’s instrument packed lab before and watched his insider’s tour of a vintage radio transmitter. Here’s hoping we get to see more of his hopped-up solder sucker in action soon.

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Reusing Motors From Washing Machines

Big ol’ motors are great when you need to get a big job done, but they can be expensive or hard to source new. However, there’s a source of big, fat, juicy motors right at home for most people – the garden variety washing machine. These motors would usually require a special controller, however [Jerry] is here to show us how to hack the controller that comes with the machine.

The hack begins as [Jerry] decides to gut a Maytag MAH7500 Neptune front loader. Many projects exist that borrow the motor but rely on a seperately sourced variable frequency drive, so the goal was to see if the machine’s original controller was usable. The machine was first troubleshooted using a factory service mode, which spins the drum at a set speed if everything is working correctly.

From there, it was a relatively simple job to source the machine schematics to identify the pinouts of the various connectors.  After some experimentation with a scope and a function generator, [Jerry] was able to get the motor spinning with the original controller doing the hard work.

It’s a simple hack, and one that relies on the availability of documentation to get the job done, but it’s a great inspiration for anyone else looking to drive similar motors in their own projects. The benefit is that by using the original motor controller, you can be confident that it’s properly rated for the motor on hand.

Perhaps instead of an induction motor, you’d rather drive a high powered brushless DC motor? This project can help.

Fighting Machine Tool Chatter with a 555 Timer

Vibration is a fact of life in almost every machining operation. Whether you’re milling, drilling, turning, or grinding, vibration can result in chatter that can ruin a part. Fighting chatter has generally been a matter of adding more mass to the machine, but if you’re clever about things, chatter reduction can be accomplished electronically, too. (YouTube, embedded below.)

When you know a little something about resonance, machine vibration and chatter start to make sense. [AvE] spends quite a bit of time explaining and demonstrating resonance in the video — fair warning about his usual salty shop language. His goal with the demo is to show that chatter comes from continued excitation of a flexible beam, which in this case is a piece of stock in the lathe chuck with no tailstock support. The idea is that by rapidly varying the speed of the lathe slightly, the system never spends very long at the resonant frequency. His method relies on a variable-frequency drive (VFD) with programmable IO pins. A simple 555 timer board drives a relay to toggle the IO pins on and off, cycling the VFD up and down by a couple of hertz. The resulting 100 RPM change in spindle speed as the timer cycles reduces the amount of time spent at the resonant frequency. The results don’t look too bad — not perfect, but a definite improvement.

It’s an interesting technique to keep in mind, and a big step up from the usual technique of more mass.

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