2025-12-09 00:30:08
People enjoy retrocomputing for a wide variety of reasons – sometimes it’s about having a computer you could fully learn, or nostalgia for chips that played a part in your childhood. There’s definitely some credit to give for the fuzzy feeling you get booting up a computer you built out of chips. Old technology does deteriorate fast, however, and RAM chip failures are especially frustrating. What if you got a few hundred DRAM chips to go through? Here’s a DRAM chip tester by [Andreas]/[tops4u] – optimized for scanning speed, useful for computers like the ZX Spectrum or Oric, and built around an ATMega328P, which you surely still have in one of your drawers.
The tester is aimed at DIP16/18/20 and ZIP style DRAM chips – [Andreas] claims support for 4164, 41256, 6416, 6464, 514256, and 44100 series RAM chips. The tester is extremely easy to operate, cheap to build, ruthlessly optimized for testing speed, sports a low footprint, and is fully open-source. If you’re ever stuck with a heap of RAM chips you want to quickly test one by one, putting together one of these testers is definitely the path to take, instead of trying to boot up your well-aged machine with a bunch of chips that’d take a while to test or, at worst, could even fry it.
[Andreas] includes KiCad PCB and Arduino source files, all under GPL. They also provide adapter PCBs for chips like the 4116. What’s more, there are PCB files to build this tester in full DIP, in case that’s more your style! It’s far from the first chip tester in the scene, of course, there are quite a few to go around, including some seriously featureful units that even work in-circuit. Not only will they save you from chips that failed, but they’ll also alert you to fake chips that are oh so easy to accidentally buy online!
2025-12-08 23:00:38
Today, it is hard to imagine a world without recorded audio, and for the most part that started with Edison’s invention of the phonograph. However, for most of its history, the phonograph was a one-way medium. Although early phonographs could record with a separate needle cutting into foil or wax, most record players play only records made somewhere else. The problem is, this cuts down on what you can do with them. When offices were full of typists and secretaries, there was the constant problem of telling the typist what to type. Whole industries developed around that problem, including the Dictaphone company.
The issue is that most people can talk faster than others can write or type. As a result, taking dictation is frustrating as you have to stop, slow down, repeat yourself, or clarify dubious words. Shorthand was one way to equip a secretary to write as fast as the boss can talk. Steno machines were another way. But the dream was always a way to just speak naturally, at your convenience, and somehow have it show up on a typewritten page. That’s where the Dictaphone company started.
Unsurprisingly, Dictaphone’s founder was the famous Alexander Graham Bell. Although Edison invented the phonograph, Bell made many early improvements to the machine, including the use of wax instead of foil as a recording medium. He actually started the Volta Graphophone Company, which merged with the American Graphophone Company that would eventually become Columbia Records.
In 1907, the Columbia Phonograph Company trademarked the term Dictaphone. While drum-based machines were out of style in other realms, having been replaced by platters, the company wanted to sell drum-based machines that let executives record audio that would be played back by typists. By 1923, the company spun off on its own.
Edison, of course, also created dictation machines. There were many other companies that made some kind of dictation machine, but Dictaphone became the standard term for any such device, sort of like Xerox became a familiar term for any copier.
Dictaphones were an everyday item in early twentieth-century offices for dictation, phone recording, and other audio applications. Not to mention a few other novel uses. In 1932, a vigilante organization used a Dictaphone to bug a lawyer’s office suspected of being part of a kidnapping.
Some machines could record and playback. Others, usually reserved for typists, were playback-only. In addition, some machines could “shave” wax cylinders to erase a cylinder for future use. Of course, eventually you’d shave it down to the core, and then it was done.
The Computer History Archives has some period commercials and films from Dictaphone, and you can see them in the videos below.
As mentioned, Dictaphone wasn’t the only game in town. Edison was an obvious early competitor. We were amused that the Edison devices had a switch that allowed them to operate on AC or DC current.
Later, other companies like IBM would join in. Some, like the Gray Audograph and the SoundScriber used record-like disks instead of belts or drums. Of course, eventually, magnetic tape cassettes were feasible, too, and many people made recorders that could be used for dictation and many other recording duties.
For the first half of the twentieth century, Dictaphones used wax cylinders. However, in 1947, they began making machines that pressed a groove into a Lexan belt — a “Dictabelt,” at first called a “Memobelt.” These were semi-permanent and, since you couldn’t easily melt over some of the wax, difficult to tamper with, which helped make them admissible in court. Apparently, you could play a Dictabelt back about 20 times before it would be too beat up to play.
These belts found many uses. For one, Dictaphone was a major provider to police departments and other similar services, recording radio traffic and telephone calls. In the late 1970s, the House Select Committee on Assassinations used Dictaphone belts from the Dallas police department recording in 1963 to do audio analysis on the Kennedy assassination. Many Dictaphones found homes in courtrooms, too.
As you can see in the commercials in the video, Dictabelts would fit in an envelope: they are about 3.5 in x 12 in or 89 mm x 300 mm. The “portable” machine promised to let you dictate from anywhere, keep meeting minutes, and more. A single belt held 15 minutes of audio, and the color gives you an idea of when the belt was made.
Of course, Dictaphone wasn’t the only game in town for machines like this. IBM released one that used a magnetic belt called a “Magnabelt’ that you could edit. Dictaphone followed suit. These, of course, were erasable.
Even as late as 1977, you could find Dictaphones in “word processing operations” like the one in the video with the catchy tune, below. Of course, computers butted into both word processing and dictation with products like Via Voice or DragonDictate. Oddly, DragonDictate is from Nuance, which bought what was left of Dictaphone.
Since this is Hackaday, of course, you want to see the insides of some of these machines. A video from [databits] gives us a peek below.
Offices have certainly changed. Most people do their own typing now. Your phone can record many hours of crystal-clear audio. Computers can even take your dictation now, if you insist.
Should you ever find a Dictabelt and want to digitize it for posterity, you might find the video below from [archeophone] useful. They make a modern playback unit for old cylinders and belts.
We’d love to see a homebrew Dictabelt recorder player using more modern tech. If you make one, be sure to let us know. People recorded on the darndest things. Tape caught on primarily because of World War II Germany and Bing Crosby.
2025-12-08 20:00:24
[Alexwlchan] noticed something funny. He knew that not putting a size for a video embedded in a web page would cause his page to jump around after the video loaded. So he put the right numbers in. But with some videos, the page would still refresh its layout. He learned that not all video sizes are equal and not all pixels are square.
For a variety of reasons, some videos have pixels that are rectangular, and it is up to your software to take this into account. For example, when he put one of the suspect videos into QuickTime Player, it showed the resolution was 1920×1080 (1350×1080). That’s the non-square pixel.
So just pulling the size out of a video isn’t always sufficient to get a real idea of how it looks. [Alex] shows his old Python code that returns the incorrect number and how he managed to make it right. The mediainfo library seems promising, but suffers from some rounding issues. Instead, he calls out to ffprobe, an external program that ships with ffmpeg. So even if you don’t use Python, you can do the same trick, or you could go read the ffprobe source code.
[Alex] admits that there are not many videos that have rectangular pixels, but they do show up.
If you like playing with ffmpeg and videos, try this in your browser. Think rectangular pixels are radical? There has been work for variable-shaped pixels.
2025-12-08 17:00:30
Do you remember those levitating lamps that were all the rage some years ago? Floating light bulbs, globes, you name it. After the initial craze of expensive desk toys, a wave of cheap kits became available from the usual suspects. [RobSmithDev] wanted to make a commemorative lamp for the Amiga’s 40th anniversary, but… it was missing something. Sure, the levitating red-and-white “boing” ball looked good, but in the famous demo, the ball is spinning at a jaunty angle. You can’t do that with mag-lev… not without a hack, anyway.
The hack [RobSmith] decided on is quite simple: the levitator is working in the usual manner, but rather than mount his “boing ball” directly to the magnet, the magnet is glued to a Dalek-lookalike plinth. The plinth holds a small motor, which is mounted at an angle to the base. Since the base stays vertical, the motor’s shaft provides the jaunty angle for the 3D-printed boing ball’s rotation. The motor is powered by the same coil that came with the kit to power the LEDs– indeed, the original LEDs are reused. An interesting twist is that the inductor alone was not able to provide enough power to run even the motor by itself: [Rob] had to add a capacitor to tune the LC circuit to the ~100 kHz frequency of the base coil. While needing to tune an antenna shouldn’t be any sort of surprise, neither we nor [Rob] were thinking of this as an antenna, so it was a neat detail to learn.
With the hard drive-inspired base — which eschews insets for self-tapping screws — the resulting lamp makes a lovely homage to the Amiga Computer in its 40th year.
We’ve seen these mag-lev modules before, but the effect is always mesmerizing. Of course, if you want to skip the magnets, you can still pretend to levitate a lamp with tensegrity.
2025-12-08 14:00:54
MIDI controllers are easy to come by these days. Many modern keyboards have USB functionality in this regard, and there are all kinds of pads and gadgets that will spit out MIDI, too. But you might also like to build your own, like this touchscreen design from [Nick Culbertson].
The build takes advantage of a device colloquially called the Cheap Yellow Display. It consists of a 320 x 240 TFT touchscreen combined with a built-in ESP32-WROOM-32, available under the part number ESP32-2432S028R.
[Nick] took this all-in-one device and turned it into a versatile MIDI controller platform. It spits out MIDI data over Bluetooth and has lots of fun modes. There’s a straightforward keyboard, which works just like you’d expect, and a nifty beat sequencer too. There are more creative ideas, too, like the bouncing-ball Zen mode, a physics-based note generator, and an RNG mode. If you liked Electroplankton on the Nintendo DS, you’d probably dig some of these. Files are on GitHub if you want to replicate the build.
These days, off-the-shelf hardware is super capable, so you can whip up a simple MIDI controller really quickly. Video after the break.
2025-12-08 11:00:39
After scouring the second-hand shops and the endless pages of eBay for original video game hardware, a pattern emerges. The size of the accessory matters. If a relatively big controller originally came with a tiny wireless dongle, after twenty years, only the controller will survive. It’s almost as if these game controllers used to be owned by a bunch of irresponsible children who lose things (wink). Such is the case today when searching for a Nintendo Wavebird controller, and [James] published a wireless receiver design to make sure that the original hardware can be resurrected.
The project bears the name Wave Phoenix. The goal was to bring new life to a legendary controller by utilizing inexpensive, readily available parts. Central to the design is the RF-BM-BG22C3 Bluetooth module. Its low power draw and diminutive footprint made it a great fit for the limited controller port space of a Nintendo GameCube. The module itself is smaller than the GameCube’s proprietary controller connector. Luckily for projects like this, there are plenty of third-party connector options available.
When it comes to assembly, [James] insists it is possible to wire everything up by hand. He included an optional custom PCB design for those of us who aren’t point-to-point soldering masters. The PCB nestles cleanly into the 3D-printed outer casing seen in the image above in the iconic GameCube purple. Once the custom firmware for the Bluetooth module is flashed, pairing is as simple as pressing the Wave Phoenix adapter pairing button, followed by pressing X and Y simultaneously on the Wavebird controller. The two devices should stay paired as long as the controller’s wireless channel dial remains on the same channel. Better yet, any future firmware updates can be transferred wirelessly over Bluetooth.
Those who have chosen to build their own Wave Phoenix adapter have been pleased with the performance. The video below from Retrostalgia on YouTube shows that input responsiveness seems to be on par with the original Nintendo adapter. Mix in a variety of 3D printed shell color options, and this project goes a long way to upcycle Wavebird controllers that may have been doomed to end up in a dumpster. So it might be time to fire up a round of Kirby Air Ride and mash the A button unencumbered by a ten-foot cord.
There are even more open source video game controller designs out there like this previous post about the Alpakka controller by Dave.
