We often think of 3D printing as a way to create specific components in our builds, everything from some hard-to-find little sprocket to a custom enclosure. More and more of the projects that grace the pages of Hackaday utilize at least a few 3D printed parts, even if the overall build itself is not something we’d necessarily consider a “printed” project. It’s the natural progression of a technology which at one time was expensive and complex becoming increasingly available to the maker and hacker.
But occasionally we see 3D printing used not to create new devices, but recreate old ones. A perfect example is the almost entirely 3D printed telegraph system created by [Matt]. Projects like this help bring antiquated technology back to a modern audience, and can be an excellent educational tool. Showing someone a diagram of how the telegraph worked is one thing, but being able to run off a copy on your 3D printer and putting a working model in their hands is quite another.
[Matt] acknowledges that he’s hardly the first person to 3D print a telegraph key, but says that he’d never seen the complete system done before. The key is perhaps the component most people are familiar with from film and old images, but alone it’s really nothing more than a momentary switch. To actually put it to use, you need a telegraph sounder on the receiving end to “play” the messages.
The sounder is a somewhat more complex device than the key, and uses an electromagnet to pull down a lever and produce an audible clicking noise. In the most basic case, the coil is directly connected to the key, but in a modern twist [Matt] has added a MOSFET into the circuit so the electromagnet is triggered locally within the sounder. This prevents sparks from eroding the contacts in the key, and alleviates problems associated with current loss over long wire runs.
There’s an old joke that all you need to fix TVs is a cheater, a heater, and a meter. If you don’t remember, a cheater was a cord to override the interlock on TVs so you could turn them on with the back removed. Of course, in real life, pro repair techs always had better equipment. In 1939 that might have meant the Supreme Vedolyzer which combined a meter, a ‘scope, and a wavemeter all in one device. [Mr Carlson] acquired one that was in fair shape and made a few videos (see below) of the teardown and restoration.
[Mr Carlson] wasn’t restoring this as an art project, by the way. He plans on using it, so he was less concerned with authenticity and more worried about usability. That led him to do things like remove the input jacks and replace them with BNCs. The video series is a bit of a time investment. Part one is about 82 minutes long! But if you are interested in old gear, this is a chance to peer inside an unusual specimen.
Late last year, artist [Steve Messam]’s project “Whistle” involved 16 steam engine whistles around Newcastle that would fire at different parts of the day over three months. The goal of the project was bring back the distinctive sound of the train whistles which used to be fixture of daily life, and to do so as authentically as possible. [Steve] has shared details on the construction and testing of the whistles, which as it turns out was a far more complex task than one might expect. The installation made use of modern technology like Raspberry Pi and cellular data networks, but when it came to manufacturing the whistles themselves the tried and true ways were best: casting in brass before machining on a lathe to finish.
The original whistles are a peek into a different era. The bell type whistle has three major components: a large bell at the top, a cup at the base, and a central column through which steam is piped. These whistles were usually made by apprentices, as they required a range of engineering and manufacturing skills to produce correctly, but were not themselves a critical mechanical component.
In the original whistle shown here, pressurized steam comes out from within the bottom cup and exits through the thin gap (barely visible in the image, it’s very narrow) between the cup and the flat shelf-like section of the central column. That ring-shaped column of air is split by the lip of the bell above it, and the sound is created. When it comes to getting the right performance, everything matters. The pressure of the air, the size of the gap, the sharpness of the bell’s lip, the spacing between the bell and the cup, and the shape of the bell itself all play a role. As a result, while the basic design and operation of the whistles were well-understood, there was a lot of work to be done to reproduce whistles that not only operated reliably in all types of weather using compressed air instead of steam, but did so while still producing an authentic re-creation of the original sound. As [Steve] points out, “with any project that’s not been done before, you really can’t do too much testing.”
Embedded below is one such test. It’s slow-motion footage of what happens when the whistle fires after filling with rainwater. You may want to turn your speakers down for this one: locomotive whistles really were not known for their lack of volume.
It’s January, and that means it’s time once again for the Consumer Electronics Show. CES is the place where electronic manufacturers from all across the globe to show off their future products and make promises they probably can’t keep. Of course there is no better indicator of a company’s future than looking at the past, and thanks to [Home & Garden Television] we have a comprehensive look at what CES was twenty three years ago. The cable channel aired a special, “Plugged In with Wil Shriner”, covering CES 1996 and it is certainly illuminating to see in hindsight. Plus it even comes complete with “cable money” tier mid 90s motion graphics.
Over on YouTube, user [videoholic] has uploaded the HGTV CES ’96 special into five separate segments (links provided below). Some of the highlights include:
We all have fond memories of a toy from our younger days. Most of which are still easy enough to get your hands on thanks to eBay or modern reproductions, but what if your childhood fancies weren’t quite as mainstream? What if some of your fondest memories involved playing with 1960’s educational games which are now so rare that they command hundreds of dollars on the second-hand market?
That’s the situation [Mike Gardi] found himself in recently. Seeing that the educational games which helped put him on a long and rewarding career in software development are now nearly unobtainable, he decided to try his hand at recreating them on his 3D printer. With his keen eye for detail and personal love of these incredible toys, he’s preserved them in digital form for future generations to enjoy.
His replica of “The Amazing Dr. Nim” needed to get scaled-down a bit in order to fit on your average desktop 3D printer bed, but otherwise is a faithful reproduction of the original injection molded plastic computer. The biggest difference is that his smaller version uses 10 mm (3/8 inch) steel ball bearings instead of marbles to actuate the three flip-flops and play the ancient game of Nim.
[Mike] has also created a replica of “Think-a-Dot”, another game which makes use of mechanical flip-flops to change the color of eight dots on the front panel. By dropping marbles in the three holes along the top of the game, the player is able to change the color of the dots to create various patterns. The aim of the game is to find the fewest number of marbles required to recreate specific patterns as detailed in the manual.
Speaking of which, [Mike] has included scans of the manuals for both games, and says he personally took them to a local shop to have them professionally printed and bound as they would have been when the games were originally sold. As such, the experience of owning one of these classic “computer” games has now been fully digitized and is ready to be called into corporeal form on demand.
The Computer History Museum in Mountain View has two operational IBM 1401 mainframes, which use IBM 1403 high-speed printers. They aren’t some decades-old notion of “high speed” that barely looks sluggish today, either. These monsters slam out ten lines per second thanks to a rotating chain of type slugs and an array of electromagnetic hammers. Every 11.1 microseconds, a character in the chain would be lined up with a hammer, and if the control circuitry identified it as a character that needed to be printed, the hammer behind the paper would drive the paper into the print ribbon and the slug, putting an imprint of the character onto the paper. When one of these printers failed with a sync error, it kicked off some serious troubleshooting to diagnose the problem.
Investigation of the problem ultimately led to an intermittent connection in a driver card due to a broken PCB trace, but by then some fuses had been blown as well. In the end the printer was brought back online, but possibly with a slightly damaged coil on one of the hammers.
[Ken]’s writeup on the repair process is highly detailed and walks through the kind of troubleshooting and repairs involved when solving problems with vintage electronics. Electrical fundamentals might be the same, but a deep understanding of not only the architecture but also the failure modes of vintage hardware is needed in order to troubleshoot effectively.
If IBM 1401 mainframes and fixing 1403 printers sounds familiar, it’s because a printer fix has been done before. That was due to a different problem, but still a challenging task to narrow down and fix.
In a way, all 7-segment displays are alike; at least from the outside looking in. On the inside it can be quite another story, and that’s certainly the case with the construction of this Soviet-era 7-segment numerical display. From the outside it may look a bit sturdier than usual, but it’s still instantly recognizable for what it is. On the inside is an unusual mixture of incandescent bulbs and plastic light guides.
The rear of the display is a PCB with a vaguely hexagonal pattern of low-voltage incandescent bulbs, and each bulb mates to one segment of the display. The display segments themselves are solid blocks of plastic, one for each bulb, and each a separate piece. These are painted black, with the only paint-free areas being a thin segment at the top for the display, and a hole in the back for the mating bulb.
The result is that each plastic piece acts as a light guide, ensuring that a lit bulb on the PCB results in one of the seven thin segments on the face being lit as well. An interesting thing is that the black paint is the only thing preventing unwanted light from showing out the front, or leaking from one segment to another; usually some kind of baffle is used for this purpose in displays from this era.
More curiously, each plastic segment is a unique shape apparently unrelated to its function. We think this was probably done to ensure foolproof assembly; it forms a puzzle that can only fit together one way. The result is a compact and remarkably sturdy unit that shows how older and rugged tech isn’t necessarily bulky. Another example of small display tech from the Soviet era is this tiny 7-segment display of a completely different manufacture, which was usually used with an integrated bubble lens to magnify the minuscule display.