A LEGO Orrery

June 9, 2024 by Al Williams 5 Comments

We aren’t sure how accurate you can get with LEGO, but a building block orrery looks cool, if nothing else. [Marian42] saw one done a few years ago and decided to build a version with a different mechanism. At first, the plan was to use some 3D printed fixtures, but the final product is made entirely from LEGO bricks. Very impressive. The video below shows that it has been complete for awhile, but the write-up that goes into great detail has only just arrived and it was worth the wait.

This is one of those things that seems simple if you don’t think too hard about it. However, when you sit down to actually do it, there are a number of challenges. For one thing, the Earth tilts at 23.5 degrees, and as the planet rotates, the tilt stays in the same direction, making it tricky to model mechanically.

The moon also has a 5.15 degree inclination, but since that’s hard to notice at this scale, the LEGO orrery exaggerates it. So, the Moon’s track has its own set of design problems. The whole thing has to rotate on a concentric shaft, which is also tricky to get right with kids’ building blocks.

Compared to the last orrery we saw, this one is huge. We’ve always been partial to ones that you have to look up to.

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Baffle The Normies With This Binary Thermometer

June 8, 2024 by Dan Maloney 9 Comments

We think it’s OK to admit that when someone puts a binary display on a project, it’s just a thinly veiled excuse to get more blinkenlights into the world. That and it’s a way to flex a little on the normies; you’ve gone pretty far down the tech rabbit hole to quickly decipher something like this binary-display thermometer, after all.

Don’t get us wrong, we think those are both perfectly valid reasons for going binary. And all things considered, a binary display for a thermometer like [Clovis Fritzen]’s is much simpler to decode than, say, a clock. Plus, it seems a bit that this build was undertaken at least partially as an exercise in Charlieplexing, which [Clovis] uses to drive the six-bit LED display using only three lines of GPIO from the Digispark ATtiny85 board running the show.

The temperature sensor is a DHT11, whose output is read by the microcontroller before being converted to binary and sent to the six-bit display. The 64-degree range is perfect for displaying the full range of temperatures most of us would consider normal, although we’d find 63°C a touch torrid so maybe there’s a little too much resolution on the upper end of the scale. Then again, switching to Fahrenheit would shift it toward the hypothermia end of the scale, which isn’t helpful. And you can just forget about Kelvin.

Linamp, The IRL Winamp

June 6, 2024 by Dan Maloney 60 Comments

Anyone who first experienced music on computers using Winamp probably shares a memory of seeing that classic UI for the first time. Everything about it was a step ahead of the clunky, chunky interfaces we were used to, and even though it was supposed to be unobtrusive, it was hard to tear your eyes off that silky-smooth spectrum analyzer bouncing out your favorite MP3s.

Recapturing a little of the Winamp magic is the goal of Linamp, an physical version of the classic media player. It reproduces the Winamp UI on a touchscreen LCD with a wide aspect ratio that almost perfectly matches the original layout. Behind the display is a Raspberry Pi 4 with a 32 GB SD card, with all the important connections brought out to a board on the back of the case. The case itself is a treat, as it borrows design elements from another bit of retro gear, the mini-rack audio systems that graced many a bookshelf in the 1980s — and powered many high school parties too, if memory serves.

To recreate the case, [Rodmg] designed a sheet metal case and had it custom-made from anodized aluminum by PCBWay. He also printed a bezel for the display that looks very similar to the Winamp window border, complete with control icons. Where the build really shines, though, is with the work [Rodmg] put into the software. He matched the original Winamp UI very closely, both in terms of layout and performance. The pains he went to to get the spectrum analyzer working, including a deep dive into FFT, are impressive.

The results speak for themselves on this one, and hats off to [Rodmg] for the effort and the ride on the nostalgia train. We don’t know if the recent announcement of Winamp’s impending open-sourcing will have much impact on this project, but it might result in a flood of new Winamp builds.

Old Knobs With A Cast Of Thousands

June 5, 2024 by Al Williams 6 Comments

You have an old radio — in the case of [The Radio Mechanic], a Stromberg Carlson — and it needs new knobs. What do you do? You can’t very well pop down to the local store and find any knobs anymore. Even if you are lucky enough to be around an electronics store, they aren’t going to have knobs to do justice to an antique radio. You could 3D print them, of course, but there are a number of issues with transferring the old knob to a CAD file for printing. So [The Radio Mechanic] decided to cast them instead.

He printed some fixtures to help with the molding using two-part molding silicone. He mounted the knob on a shaft in a jig, filled the jig with silicone, and lowered the knob into the mix. The next day, he had a good-looking mold.

The next step, of course, is to cast with resin. Admittedly 3D printing would have been faster, but would not have as nice a surface finish. The epoxy resin is clear, but he was hopeful that some caramel pigment would match the original knob color. Spoiler alert: it didn’t. The resulting knob looked translucent, like a root beer barrel candy, rather than the brown sugar color of the original knob.

The knob needed a spring insert to hold the shaft, so he repurposed some from a different kind of radio. Overall, this is the kind of thing we always think we are going to do when we need something and then we rarely follow through. Then again, we rarely have the patience to wait as long as these two knobs took to make.

Of course, a casting guerrilla doesn’t have to make just knobs. You can even add metal powders to do cold metal casting.

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Displays We Like Hacking: HDMI

June 5, 2024 by Arya Voronova 26 Comments

I don’t like HDMI. Despite it being a pretty popular interface, I find crucial parts of it to be alien to what hackers stand for. The way I see it, it manages to be proprietary while bringing a lot of the old cruft in. It doesn’t have a native alternative like DisplayPort, so portable implementations tend to suffer power-wise; the connector situation is interesting, and the HDMI Foundation has been doing some weird stuff; in particular, they are pretty hostile to open-source technology.

This article is not the place for such feelings, however, especially since I’ve expressed them enough in the DisplayPort article. We the hackers deserve to be able to handle the interfaces we stumble upon, and I firmly believe in that way more than in my right to animosity towards HDMI.

The HDMI interface is seriously prominent wherever you look, in part because it’s the interface created by the multimedia-involved companies for the multimedia-involved companies. Over the years we’ve had it, it’s been more than sufficient for basically everything we do video-wise, save for the highest resolutions.

It’s also reasonably simple to wire up, hack on, and even bitbang. Let’s go through what makes it tick.

The Core

HDMI is, at its core, three differential pairs for data, plus one pair to clock them and in the darkness bind them. It’s a digital interface, though it is a fun one. This makes it way more suitable for higher-distance video transmissions than interfaces like VGA, and as long as you stick to relatively low resolutions, HDMI won’t have as many asks in terms of PCB layout as DisplayPort might, thanks to HDMI link speeds scaling proportionally with the display resolution.

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VFD Tube Calculator Shows Off Wide Array Of Skills

June 4, 2024 by Tom Nardi 3 Comments

With all the tools and services available to us these days, it’s hard to narrow down a set of skills that the modern hacker or maker should have. Sure, soldering is a pretty safe bet, and most projects now require at least a little bit of code. But the ability to design 3D printable parts has also become increasingly important, and you could argue that knowledge of PCB design and production is getting up there as well. With home laser cutters on the rise, a little 2D CAD wouldn’t hurt either. So on, and so on.

If you ever wanted an example of the multitude of skills that can go into a modern hardware project, take a look at this gorgeous Vacuum Fluorescent Display (VFD) tube calculator built by [oskar2517]. As fantastic as the final product is, we were particularly impressed with everything it took to get this one over the finish line.

A .7 mm walnut veneer covers the pieced together plywood frame.

It’s got it all: 3D printed parts, a laser cut wooden frame, a custom PCB, and even a bit of old school woodworking. To top it all off, the whole thing has been meticulously documented.

But what’s perhaps most impressive here is that [oskar2517] was approaching most of these techniques for the first time. They had never before worked with IV-12 tubes, designed an enclosure in 3D, had parts laser cut, applied wood veneer, or designed a custom PCB. They did have solid experience writing code in C at least, which did make developing the Arduino firmware a bit easier.

Although they might look outwardly similar, VFD tubes like the IV-12 are easier to work with than Nixie tubes thanks to their lower operating voltage. That said, a look through our archives shows that projects using Nixies outnumber VFD tubes by nearly four to one, so there’s no shortage of folks willing to take on the extra effort for that sweet warm glow.

A Human-Sized Strowger Telephone Exchange

June 3, 2024 by Jenny List 3 Comments

A large hacker camp such as EMF 2024 always brings unexpected delights, and one of those could be found in the Null Sector cyberpunk zone: a fully functional Strowger mechanical telephone exchange. Better still, this wasn’t the huge array of racks we’ve come to expect from a mechanical exchange, but a single human-sized unit, maybe on a similar scale to a large refrigerator. [LBPK]’s PAX, or Private Automatic Exchange, is a private telephone network, 1950s style.

It stood at the back of the container, with a row of four telephones in front of it. We particularly liked the angular “Trimphone”, the height of 1960s and 70s chic. You could dial the other phones in the network with a two digit number, and watch the exchange clicking in the background as you did so. Some of the sounds weren’t quite the same as the full-sized equivalents, with the various tones being replaced by vibrating reeds.

This exchange has an interesting history, being built in 1956 by “Automatic Telephone & Electric” for the Midlands Electricity Board, power generator for much of central England, where it served its commercial life. On decommissioning it went to the Ffestiniog narrow gauge railway, in Wales. He was lucky enough to learn of its existence when the Ffestiniog had no further use for it, and snapped it up.

We have to admit, we want one of these, however he makes clear that it’s an unwieldy machine that requires quite some attention so a Hackaday mechanical exchange will have to remain a dream for now.