Dot-Matrix Printer Brings Old School Feel To Today’s Headlines

October 9, 2024 by 20 Comments

If you remember a time when TV news sets universally incorporated a room full of clattering wire service teleprinters to emphasize the seriousness of the news business, congratulations — you’re old. Now, most of us get our news piped directly into our phones, selected by algorithms perfectly tuned to rile us up on whatever the hot-button issue du jour happens to be. Welcome to the future.

If like us you long for a simpler way to get your news, [Andrew Schmelyun] has a partial solution with this dot-matrix news feeder. It’s part of his effort to detox a bit from the whole algorithm thing and make the news a little more concrete. He managed to chase down a very old Star Micronics printer with a serial interface, which he got on the cheap thanks to the previous owner not being sure if it worked. It did, at least after some cleaning, and thanks to a USB-to-serial and the efforts of Linux kernel hackers through the ages, was able to echo output to the printer from a Raspberry Pi Zero W.

From there, getting a daily news feed was as simple as writing some PHP code to mine the APIs of a few selected services. We’re perplexed and alarmed to report that Hackaday is not among the selected sources, but we’re sure this was just a small oversight that will be corrected in version 2. The program runs as a cron job so that a dead-tree version of the day’s top stories is ready for [Andrew]’s morning coffee.

We’ve seen similar news printers before; we particularly like this roll-feed paper version. But for a seriously retro feel, we’d love to see this done on a real teletype.

What Happened To Duracell PowerCheck?

October 9, 2024 by 83 Comments

Remember Duracell’s PowerCheck? The idea was that a strip built into the battery would show if the battery was good or not. Sure, you could always get a meter or a dedicated battery tester — but PowerCheck put the tester right in the battery. [Technology Connections] has an interesting video on how these worked and why you don’t see them today. You can see it below.

Duracell didn’t invent the technology. The patent belonged to Kodak, and there were some patent issues, too, but the ones on the Duracell batteries used the Kodak system. In practice, you pushed two dots on the battery, and you could see a color strip that showed how much capacity the battery had left. It did this by measuring the voltage and assuming that the cell’s voltage would track its health. It also assumed — as is clearly printed on the battery — that you were testing at 70 degrees F.

The temperature was important because the secret to the PowerCheck is a liquid crystal that turns color as it gets hot. When you press the dots, the label connects a little resistor, causing the crystals to get warm. The video shows the label taken apart so you can see what’s inside of it. The resistor isn’t linear so that’s how it changes only part of the bar to change color when the battery is weak but not dead.

It is a genius design that is simple enough to print on a label for an extremely low cost and has virtually no components. PowerCheck vanished from batteries almost as suddenly as it appeared. Some of it was due to patent disputes. But the video purports that normal people don’t really test batteries.

Watch out for old batteries in gear. Of course, if you want to really test batteries, you are going to need more equipment.

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That’ll Go Over Like A Cement Airplane

October 8, 2024 by 37 Comments

Most of us have made paper airplanes at one time or another, but rather than stopping at folded paper, [VirgileC] graduated to 3D printing them out of PLA. Then the obvious question is: can you cast one in cement? The answer is yes, you can, but note that the question was not: can a cement plane fly? The answer to that is no, it can’t.

Of course, you could use this to model things other than non-flying airplanes. The key is using alginate, a natural polymer derived from brown seaweed, to form the mold. The first step was to suspend the PLA model in a flowerpot with the holes blocked. Next, the flowerpot gets filled with alginate.

After a bit, you can remove the PLA from the molding material by cutting it and then reinserting it into the flower pot. However, you don’t want it to dry out completely as it tends to deform. With some vibration, you can fill the entire cavity with cement.

The next day, it was possible to destroy the alginate mold and recover the cement object inside. However, the cement will still be somewhat wet, so you’ll want to let the part dry further.

Usually, we see people print the mold directly using flexible filament. If you don’t like airplanes, maybe that’s a sign.

Soaring At Scale: Modular Airship Design

October 8, 2024 by 31 Comments

If you’re looking for an intriguing aerial project, [DilshoD] has you covered with his unique twist on modular airships. The project, which you can explore in detail here, revolves around a modular airship composed of individual spherical bodies filled with helium or hydrogen—or even a vacuum—arranged in a 3x3x6 grid. The result? A potentially more efficient airship design that could pave the way for lighter-than-air exploration and transport.

The innovative setup features flexible connecting tubes linking each sphere to a central gondola, ensuring stable expansion without compromising the airship’s integrity. What’s particularly interesting is [DilshoD]’s use of hybrid spheres: a vacuum shell surrounded by a gas-filled shell. This dual-shell approach adds buoyancy while reducing overall weight, possibly making the craft more maneuverable than traditional airships. By leveraging materials like latex used in radiosonde balloons, this design also promises accessibility for makers, hackers, and tinkerers.

Though this concept was originally submitted as a patent in Uzbekistan, it was unfortunately rejected. Nevertheless, [DilshoD] is keen to see the design find new life in the hands of Hackaday readers. Imagine the possibilities with a modular airship that can be tailored for specific applications. Interested in airships or modular designs? Check out some past Hackaday articles on DIY airships like this one, and dive into [DilshoD]’s full project here to see how you might bring this concept to the skies.

A Flip Digit Clock, Binary Style

October 8, 2024 by 7 Comments

Flip digit clocks are a prized piece of consumer electrical ephemera, providing as they do a digital display without significant electronics. Making your own flip digit display involves some drudgery in the production of all those flip cards, but how would it seem if the complexity was reduced? Go from base 10 to base 2 for example, and a binary flip digit display can be made from flip dot display parts. [Marcin Saj] has done just that, resulting in a timepiece that’s a few bits out of the ordinary.

Under the hood though it’s slightly more conventional, with the trusty ATmega328 and Arduino bootloader, whose software drives the dot electromagnets via a set of MOSFET drivers. It’s a nice project which if you want there’s a Kickstarter to buy one, but the files are also available from a GitHub repository if you’d like to have a go for yourself. Meanwhile you can see it in action in the video below the break.

We like this clock, as it’s different from the norm in Arduino clocks. It’s not however the first flip dot clock we’ve seen, this one has a full dot matrix display.

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Mechanical Tool Changing 3D Printing Prototype

October 8, 2024 by 5 Comments

Tool changing 3D printers are hot. The idea is that instead of switching filament, you swap out hot ends or other tools. That isn’t a new idea. However, most tool changers are expensive. [Engineers Grow] has one that is simple and inexpensive, relying on the printer’s own motors and some clever mechanics.

The first step was to make a modified extruder that allowed the filament to load and unload. The first attempt didn’t work well, but that is the nice thing about 3D printing — it is easy to try again. There is only one extruder, which is good from the standpoint that you don’t need a control board with many outputs and you avoid the expense of multiple extruders.

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Art of 3D printer in the middle of printing a Hackaday Jolly Wrencher logo

3D Printering: Listen To Klipper

October 8, 2024 by 10 Comments

I recently wrote about using Klipper to drive my 3D printers, and one natural question is: Why use Klipper instead of Marlin? To some degree that’s like asking why write in one programming language instead of another. However, Klipper does offer some opportunities to extend the environment more easily. Klipper runs on a Linux host, so you can do all of the normal Linux things.

What if you wanted to create a custom G-code that would play a wave file on a speaker? That would let you have custom sounds for starting a print, aborting a print, or even finishing a print.

If you recall, I mentioned that the Klipper system is really two parts. Well, actually more than two parts, but two important parts at the core. Klipper is, technically, just the small software stub that runs on your 3D printer. It does almost nothing. The real work is in Klippy, which is mostly Python software that runs on a host computer like a Raspberry Pi or, in my case, an old laptop.

Because it is Python and quite modular, it is very simple to write your own extensions without having to major surgery or even fork Klipper. At least in theory. Most of the time, you wind up just writing G-code macros. That’s fine, but there are some limitations. This time, I’m going to show you how easy it can be using the sound player as an example.

Macros All the Way Down

Normally, you think of gcode as something like: G1 X50 Y50. Some of the newer codes don’t start with G, but they look similar. But with Klipper, G1, M205, and MeltdownExtruder are all legitimate tokens that could be “G-code.”

For example, suppose you wanted to implement a new command called G_PURGE to create a purge line (case doesn’t matter, by the way). That’s easy. You just need to put in your configuration file:

[gcode_macro g_purge]
gcode:
# do your purge code here

The only restriction is that numbers have to occur at the end of the name, if at all. You can create a macro called “Hackaday2024,” but you can’t create one called “Hackaday2024_Test.” At least, the documentation says so. We haven’t tried it.

There’s more to macros. You can add descriptions, for example. You can also override an existing macro and even call it from within your new macro. Suppose you want to do something special before and after a G28 homing command:

[gcode_macro g28]
description: Macro to do homing (no arguments)
rename_existing: g28_original
gcode:
M117 Homing...
g28_original
M117 Home done....

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