We’ve seen a lot of clever re-imagining of the classic 7-segment display, and proving there is still room for something new is [Jack]’s 7-segment “DigiTag” display.
This 3D printable device has a frame into which is slotted three sliders. These sliders can be adjusted individually, mixing and matching the visibility of colored and uncolored areas, to create digits 0-9. We’ve seen some unusual 7-segment-inspired displays before, using from one motor for the whole digit to ones that need one motor per segment, but nothing quite like this approach.
While this particular design relies on the user to manually “dial in” each digit, the resulting key-like assembly (and unique shape for each digit) seems like it could have some interesting applications — a puzzle box design comes to mind.
If you have any ideas of your own on how this could be used, don’t keep them to yourself! Let us know in the comments, below.
You can buy small modules with capacitive touch detection ICs — most often it’s the TTP223, a single-button capacitive model with configurable output modes. These are designed to pair with a microcontroller or some simple logic-level input, but [Alain Mauer] wanted was to bring touch control to a simple LED strip. Not to be set deterred, he’s put together a simple TTP223-based switch board.
Initially, he made a prototype using one of the regular TTP223 boards as a module, but then transferred the full schematic onto a single PCB. The final board uses an NPN transistor capable of handling up to 3 amps to do the switching job, and Zener-based regulation to provide 5 V for the TTP223 itself from the 12 V input. [Alain] shares the schematic, as well as BOM together with Gerber files for a 2×3 panel in case you’re interested in adding a few of these handy boards to your parts bin.
You can achieve a lot with a Dremel. For instance, apparently you can slim the original NES down into the hand-held form-factor. Both the CPU and the PPU (Picture Processing Unit) are 40-pin DIP chips, which makes NES minification a bit tricky. [Redherring32] wasn’t one to be stopped by this, however, and turned these DIP chips into QFN-style-mounted dies (Nitter) using little more than a Dremel cutting wheel. Why? To bring his TinyTendo handheld game console project to fruition, of course.
DIP chip contacts go out from the die using a web of metal pins called the leadframe. [Redherring32] cuts into that leadframe and leaves only the useful part of the chip on, with the leadframe pieces remaining as QFN-like contact pads. Then, the chip is mounted onto a tailored footprint on the TinyTendo PCB, connected to all the other components that are, thankfully, possible to acquire in SMD form nowadays.
This trick works consistently, and we’re no doubt going to see the TinyTendo being released as a standalone project soon. Just a year ago, we saw [Redherring32] cut into these chips, and wondered what the purpose could’ve been. Now, we know: it’s a logical continuation of his OpenTendo project, a mainboard reverse-engineering and redesign of the original NES, an effort no doubt appreciated by many a NES enthusiast out there. Usually, people don’t cut the actual chips down to a small size – instead, they cut into the mainboards in a practice called ‘trimming’, and this practice has brought us many miniature original-hardware-based game console builds over these years.
On no planet is making your own X-ray tube a good idea. But that doesn’t mean we’re not going to talk about it, because it’s pretty darn cool.
And when we say making an X-ray tube, we mean it — [atominik] worked from raw materials, like glass test tubes, tungsten welding electrodes, and bits of scrap metal, to make this dangerously delightful tube. His tool setup was minimalistic as well– where we might expect to see a glassblower’s lathe like the ones used by [Dalibor Farny] to make his custom Nixie tubes, [atominik] only had a small oxy-propane hand torch to work with. The only other specialized tools, besides the obvious vacuum pump, was a homebrew spot welder, which was used to bond metal components to the tungsten wires used for the glass-to-metal seals.
Although [atominik] made several versions, the best tube is a hot cathode design, with a thoriated tungsten cathode inside a copper focusing cup. Across from that is the anode, a copper slug target with an angled face to direct the X-rays perpendicular to the long axis of the tube. He also included a titanium electrode to create a getter to scavenge oxygen and nitrogen and improve the vacuum inside the tube. All in all, it looks pretty similar to a commercial dental X-ray tube.
The demonstration in the video below is both convincing and terrifying. He doesn’t mention the voltage he’s using across the anode, but from the cracking sound we’d guess somewhere around 25- to 30 kilovolts. The tube really gets his Geiger counter clicking.
Here’s hoping [atominik] is taking the proper precautions during these experiments, and that you do too if you decide to replicate this. You’ll also probably want to check out our look at the engineering inside commercial medical X-ray tubes.
It’s easy to see why LEDs largely won out over neon bulbs for pilot light applications. But for all the practical utility of LEDs, they’re found largely lacking in at least one regard over their older indicator cousins: charm. Where LEDs are cold and flat, the gentle orange glow of a neon lamp brings a lot to the aesthetics party, especially in retro builds.
But looks aren’t the only thing these tiny glow lamps have going for them, and [David Lovett] shows off some of the surprising alternate uses for neon lamps in his new video. He starts with an exploration of the venerable NE-2 bulb, which has been around forever, detailing some of its interesting electrical properties, like the difference between the voltage needed to start the neon discharge and the voltage needed to maintain it. He also shows off some cool neon lamp tricks, like using them for all sorts of multi-vibrator circuits without anything but a few resistors and capacitors added in. The real fun begins when he breaks out the MTX90 tube, which is essentially a cold cathode thyratron. The addition of a simple control grid makes for some interesting circuits, like single-tube multi-vibrators.
The upshot of all these experiments is pretty clear to anyone who’s been following [David]’s channel, which is chock full of non-conventional uses for vacuum tubes. His efforts to build a “hollow state” computer would be greatly aided by neon lamp circuits such as these — not to mention how cool they’d make everything look.
We’re going to go out on a limb and predict that future history books will note that the decision to invade a sovereign nation straight after a worldwide pandemic wasn’t exactly the best timing. Turns out the global electronics shortage the pandemic helped to catalyze isn’t just affecting those of us with peaceful intentions, as the Russian war machine is having a few supply issues with the parts needed to build modern weapons and their associated control equipment.
As you might expect, many of these parts are electronic in nature, and in some cases they come from the same suppliers folks like us use daily. This article from POLITICO includes an embedded spreadsheet, broken down by urgency, complete with part numbers, manufacturers, and even the price Moscow expects to pay!
Chips from US-based firms such as Texas Instruments are particularly hard for the Kremlin to source.
So what parts are we talking about anyway? The cheapest chip on the top priority list is the Marvell ‘Alaska’ 88E1322 which is a dual Gigabit Ethernet PHY costing a mere $7.10 USD according to Moscow. The most expensive is the 10M04DCF256I7G, which is an Altera (now Intel) Max-10 series FPGA, at $1,101 USD (or 66,815 Rubles, for those keeping score).
But it’s not just chips that are troubling them, mil-spec D-sub connectors by Airborn are unobtainable, as are all classes of basic passive parts, resistors, diodes, discrete transistors. Capacitors are especially problematic (aren’t they always). A whole slew of Analog Devices chips, as well as many from Maxim, Micrel and others. Even tiny logic chips from Nexperia.
Of course, part of this is by design. Tightened sanctions prevent Russia from purchasing many of these parts directly, which is intended to make continued aggression as economically unpleasant as possible. But as the POLITICO article points out, it’s difficult to prevent some intermediaries from ‘helping out’ without the West knowing. After all, once a part hits the general market, it is next to impossible to guarantee where it will eventually get soldered down.
More specifically, the authors wanted to examine the use of 3D printing components to be used in a vacuum. Parts produced with filament-based printers tend to be porous, and as such, are not suitable for fittings or adapters which need to be pumped down to below one atmosphere. The paper goes on to explain that there are coatings that can be used to seal the printed parts, but that they can outgas at negative pressures.
The solution proposed by the team is exceptionally simple: after printing their desired parts in polypropylene on a Lulzbot Taz 6, they simply hit them with a standard consumer heat gun. With the temperature set at ~400 °C, it took a little under a minute for the surface of take on a glossy appearance — the result reminds us of an ABS print smoothed with acetone vapor.
As the part is heated, the surface texture visibly changes. The smoothed parts performed far better in vacuum testing.
In addition to the heat treatment, the team also experimented with increasing degrees of infill overlap in the slicer settings. The end result is that parts printed with a high overlap and then heat treated were able to reliably handle pressures as low as 0.4 mTorr. While the paper admits that manually cooking your printed parts with a heat gun isn’t exactly the ideal solution for producing vacuum-capable components, it’s certainly a promising start and deserves further study.
This 3D printable device has a frame into which is slotted three sliders. These sliders can be adjusted individually, mixing and matching the visibility of colored and uncolored areas, to create digits 0-9. We’ve seen some unusual 7-segment-inspired displays before, using from one motor for the whole digit to ones that need one motor per segment, but nothing quite like this approach.
