2025-01-30 20:00:47
A few years ago [Brian McCafferty] created a nice big RGB LED panel in a poster frame that aimed to be easy to move, program, and display. We’d like to draw particular attention to one of his construction methods. On the software end of things there are multiple ways to get images onto a DIY RGB panel, but his assembly technique is worth keeping in mind.
The technique we want to highlight is not the fact that he used table tennis balls as the diffusers, but rather the particular manner in which he used them. As diffusers, ping-pong balls are economical and they’re effective. But you know what else they are? An inconvenient size!
An LED strip with 30 LEDs per meter puts individual LEDs about 33 mm apart. A regulation ping-pong ball is 40 mm in diameter, making them just a wee bit too big to fit nicely. We’ve seen projects avoid this problem with modular frames that optimize spacing and layout. But [Brian]’s solution was simply to use force.
Observing that ping-pong balls don’t put up much of a fight and the size mismatch was relatively small, he just shoved those (slightly squashy) 40 mm globes into 33 mm spacing. It actually looks… perfectly fine!
We suspect that this method doesn’t scale indefinitely. Probably large displays like this 1200 pixel wall are not the right place to force a square peg into a round hole, but it sure seemed to hit the spot for his poster-sized display. Watch it in action in the video below, or see additional details on the project’s GitHub repository.
2025-01-30 17:00:15
In the mid 1980s, there was a rash of 16-bit computers entering the market. One of them stood head and shoulders above the rest: Commodore’s Amiga 1000. It had everything that could reasonably be stuffed into a machine of the period, and multimedia capabilities the rest wouldn’t catch up on for years. [Celso Martinho] has managed to secure one of those first machines, and has shared his tale of bringing it back to life.
The post is as much a love letter to the Amiga and review of A1000 peripherals as it is a restoration, which makes it a good read for retrocomputing enthusiasts. He recapped it and it wouldn’t boot, the solution of which turned out to be a reminder for the rest of us.
The machine had a RAM upgrade in the form of a daughterboard under the processor, its pins had weakened the leaves of the processor socket so it wouldn’t make contact. So don’t forget to replace sockets as well as capacitors.
The resulting machine is much faster thanks to a modern upgrade with a much quicker processor, memory, and an SD card for storage. He goes into some of the other upgrades available today, all of which would have had early-1990s-us salivating. It’s fair to say that in 2025 an A1000 is more 40-year-old curio than useful modern computer, but we can’t fail to admit to a bit of envy. The Amiga holds a special affection, here.
2025-01-30 14:00:09
VFDs — vacuum fluorescent displays — have a distinctive look, and [Anthony Francis-Jones] is generally fascinated with retro displays. So, it makes sense that he’d build a VFD project as an excuse to explain how they work. You can see the video below.
VFDs are almost miniature CRTs. They are very flexible in what they display and can even use color in a limited way. The project [Anthony] uses as an example is an indicator to show the video number he’s currently making.
The glass display is evacuated and, like a tube, has a getter to consume the last of the gas. There’s a filament that emits electrons, a grid to control their flow, and anodes coated with a fluorescent material. Unlike a regular tube, the filaments have to operate cool so they don’t glow under operation.
When the grid is positive, and the anode is also positive, that anode will glow. The anodes can be arranged in any pattern, although these are made as seven-segment displays. The filament on the tubes in this project runs on 1.5V, and the anodes need about 25V.
The project itself is fairly simple. Of course, you need a way to control the 25V anode and grid voltages, but that’s easy enough to do. It is possible to make VFDs in unusual character shapes. They work well as light sources for projection displays, too.
2025-01-30 11:00:16
Even before entering the mystical realms of UHF design, radio frequency (RF) circuits come with a whole range of fun design aspects as well. A case in point can be found in transmission line transformers, which are commonly used in RF power amplifiers, with the Guanella transformer (balun) being one example. Allowing balanced and unbalanced (hence ‘balun’) systems to interface without issues, they’re both very simple and very complex. This type of transformer and its various uses is explained in a video by [FesZ Electronics], and also the subject of an article by [Dr. Steve Arar] as part of a larger series, the latter of which is recommended to start with you’re not familiar with RF circuitry.
Transmission line transformers are similar to regular transformers, except that the former relies on transmission line action to transfer energy rather than magnetic flux and provides no DC isolation. The Guanella balun transformer was originally described by Gustav Guanella in 1944. Beyond the 1:1 balun other configurations are also possible, which [Dr. Arar] describes in a follow-up article, and which are also covered in the [FesZ] video, alongside the explanation of another use of Guanella transformers: as an impedance transformer. This shows just how flexible transformers are once you can wrap your mind around the theory.
We have previously covered RF amplifier builds as well as some rather interesting balun hacks.
Heading image: The Guanella 1:1 balun. (Credit: Steve Arar)
2025-01-30 08:00:46
Let’s face it—seeing a good tool go to waste is heartbreaking. So when his cordless drill’s motor gave up after some unfortunate exposure to the elements, [Chaz] wasn’t about to bin it. Instead, he embarked on a brave journey to breathe new life into the machine by swapping its dying brushed motor for a sleek brushless upgrade.
Things got real as [Chaz] dismantled the drill, comparing its guts to a salvaged portable bandsaw motor. What looked like an easy swap soon became a true hacker’s challenge: incompatible gear systems, dodgy windings, and warped laminations. Not discouraged by that, he dreamed up a hybrid solution: 3D-printing a custom adapter to make the brushless motor fit snugly into the existing housing.
The trickiest part was designing a speed control mechanism for the brushless motor—an impressively solved puzzle. After some serious elbow grease and ingenuity, the franken-drill emerged better than ever. We’ve seen some brushless hacks before, and this is worth adding to the list. A great tool hack and successful way to save an old beloved drill. Go ahead and check out the video below!
2025-01-30 05:00:34
[Stephen] recently wrote in to share his experiments with using the LimeSDR mini to conduct a bit of piracy on the airwaves, and though we can’t immediately think of a legitimate application for spamming the full FM broadcast band simultaneously, we can’t help but be fascinated by the technique. Called the Taylorator, as it was originally intended to carpet bomb the dial with the collected works of Taylor Swift on every channel, the code makes for some interesting reading if you’re interested in the transmission-side of software defined radio (SDR).
The write-up talks about the logistics of FM modulation, and how quickly the computational demands stack up when you’re trying to push out 100 different audio streams at once. It takes a desktop-class CPU to pull it off in real-time, and eats up nearly 4 GB of RAM.
You could use this project to play a different episode of the Hackaday Podcast on every FM channel at once, but we wouldn’t recommend it. As [Stephen] touches on at the end of the post, this is almost certainly illegal no matter where you happen to live. That said, if you keep the power low enough so as not to broadcast anything beyond your home lab, it’s unlikely anyone will ever find out.
