2025 One Hertz Challenge: Metronalmost Is Gunning For Last Place

July 15, 2025 by Tyler August 18 Comments

We’ve just begun to receive entries to the One Hertz Challenge, but we already have an entry by [Mike Coats] that explicitly demands to be awarded last place: the Metronalmost, a metronome that will never, ever, tick at One Hertz.

Unlike a real metronome that has to rely on worldly imperfections to potentially vary the lengths of its ticks, the metronoalmost leaves nothing to chance: it’s driven by a common hobby servo wired directly to a NodeMCU ESP-12E, carefully programmed so that the sweep will never take exactly one second.

This is the distribution. The gap is around the value we explicitly asked for.

The mathematics required to aggressively subvert our contest are actually kind of interesting: start with a gaussian distribution, such as you can expect from a random number generator. Then subtract a second, narrower distribution centered on one (the value we, the judges want to see) to create a notch function. This disribution can be flipped into a mapping function, but rather than compute this on the MCU, it looks like [Mike] has written a lookup table to map values from his random number generator. The output values range from 0.5 to 1.5, but never, ever, ever 1.0.

The whole thing goes into a cardboard box, because you can’t hit last place with a masterfully-crafted enclosure. On the other hand, he did print out and glue on some fake woodgrain that looks as good as some 1970s objects we’ve owned, so there might be room for (un)improvement there.

While we can’t think of a better subversion of this contest’s goals, there’s still time to come up with something that misses the point even more dramatically if you want to compete with [Mike] for last place: the contest deadline is 9:00 AM Pacific time on August 19th.

Or, you know, if you wanted to actually try and win. Whatever ticks your tock.

A Chip8 Emulator For 68000-based Macs

July 15, 2025 by Tyler August 23 Comments

Among this crowd, it’s safe to say that the original 68000 Macintosh computers need no introduction, but it’s possible some of you aren’t familiar with Chip8. It was an interpreted virtual machine originally created for the COSMAC VIP microcomputer by [Joe Weisbecker] way back in 1977. It enabled coding simple games on the COSMAC VIP without getting into machine code on the VIP’s CDP1802 processor. For the obvious reason of “Why not?” [KenDesigns] decided to put the two together with Chip4Mac68000, a Chip8 emulator for the original Macintosh.

Chip4Mac68000 is not actually a Macintosh program; it doesn’t run in the System Software. Instead, it is a bootdisk that runs bare-metal on the 68000 processor, bypassing Apple’s ROM completely. Doing that is probably more impressive than emulating Chip8 — anyone who wants to get into writing emulators starts with Chip8. That’s not to knock on anyone who goes to the effort of writing an emulator, it’s just that given its origins in a 1970s micro, it’s understandably a very simple system. Not many people do bare-metal coding on this sort of hardware anymore; it’s not like there’s an SDK you can go grab.

Or there wasn’t, anyway, because in order to get this emulator to work, [KenDesigns] wrote a bare-metal SDK for 68000-based Macs. Note that when he says 68000, he does mean 68000 — anything newer than a Macintosh Classic is out. It’s 68000, not 680xx. It was not a trivial endeavour. In the demo video embedded below, you can see his 512k Macintosh in pieces because he’s been poking at it with a logic analyzer to verify the hardware does what he thinks it’s being told.

If you want to try it out, apparently you don’t need real hardware: [KenDesigns] says MAME is accurate enough to make it all work, but miniVmac is not. No word if it would work on the RP2040-based PicoMac; if you try it, let us know how it works out.

This isn’t the first time we’ve seen people writing new software for old Macs of late. If you’re working new magic on very old machines, drop us a line. We’d love to hear about it.

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2025 One Hertz Challenge: Valvano Clock Makes The Seconds Count

July 14, 2025 by Tyler August 3 Comments

A man named [Jim Valvano] once said “There are 86,400 seconds in a day. It’s up to you to decide what to do with them.” — while we couldn’t tell you who [Jim Valvano] was without a google search*, his math checks out. The quote was sufficiently inspirational to inspire [danjovic] to create a clock count those seconds precisely.

It’s a simple project, both conceptually and electrically. All it does is keep time and count the seconds in the day– a button press switches between counting down, counting up, and HH:MM:SS. In every mode, though, the number displayed will change at one Hertz, which we appreciate as being in the spirit of the challenge. There are only four components: an Arduino Nano, a DS3231 RTC module, a SSD1306 128×64 OLED module, and a momentary pushbutton. At the moment it appears this project is only on breadboard, which is a shame– we think it deserves to have a fancy enclosure and pride of place on the wall. Wouldn’t you be more productive if you could watch those 86,400 seconds ticking away in real time? We think it would be motivating.

Perhaps it will motivate you to create something for our One Hertz Challenge. Plenty of seconds to go until the deadline on August 19th, after all. If you’d rather while away the time reading, you can check out some of [danjovic]’s other projects, like this Cistertian-inspired clock, or this equally-inscruitable timekeeper that uses binary-coded octal.

*Following a google search, he was an American college basketball coach in the mid-20th century.

Explore The Granddaddy Of All Macs With LisaGUI

July 14, 2025 by Tyler August 23 Comments

Sure, Apple’s Lisa wasn’t the first computer released with a graphical user interface — Xerox was years ahead with the Alto and the Star workstation — but Lisa was the first that came within the reach of mere mortals. Which doesn’t mean many mortals got their hands on one; with only about 10,000 sold, they were never common, and are vanishingly rare nowadays. Enter [Andrew Yaros], who has graced the world with LisaGUI, an in-browser recreation of the Lisa Office System in Javascript.

Lisa’s GUI varies from modern conventions in a few interesting ways. For one, it is much more document-focused: if you double-click on LisaType, you do not start the program. Instead you “tear off” a document from the “pad” icon of LisaType, which you can then open with another double click. The desktop is also not a folder for files to live permanently, but a temporary space. You can “set aside” a file to the desktop, but its home on disk is unchanged.

Unlike the family of Mac emulators, LisaGUI does not purport to be a perfect replica. [Andrew] has made a few quality-of-life improvements for modern users, as well as a few innovations of his own. For instance, menus are now “sticky”– on the Lisa, you had to hold down the mouse to keep them open, and release on the appropriate entry. LisaGUI leaves the menu open for you to click the entry, as on a later Macintosh.

Obviously the menu bar clock and FPS counter are not native to the Lisa; nor is the ability to theme the icons and change (1-bit) colour palettes. The ability to draw unique icons to assign to documents is all [Andrew], but is something we wish we had back in the day. He also makes no attempt to enforce the original aspect ratio, so you’ll be dragging the window to get 4:3 if that’s your jam.

Right now it does not look as though there’s much original software aside from LisaType. We would have loved to see the famous LisaProject, which was the original “killer app” that led NASA to purchase the computer. Still, this is an Alpha and it’s possible more software is to come, if it doesn’t run afoul of Apple’s IP. Certainly we are not looking too hard at this gift horse’s chompers. What’s there is plenty to get a feel for the system, and LisaGUI should be a treat for retrocomputer enthusiasts who aren’t too anal about period-perfect accuracy.

We stumbled across this one in a video from [Action Retro] in which he (the lucky dog) also shows off his Lisa II, the slightly-more-common successor.

Hurdy-posting Continues With The Balfolk Boombox, A Synth Gurdy

July 13, 2025 by Tyler August 2 Comments

The Hurdy-Gurdy continues to worm its way into pole position as the hacker’s instrument. How else could you explain a medieval wheel fiddle being turned into a synthesizer? Move over, keytar — [Rory Scammell]’s Balfolk Boombox is the real deal.

It began life as MIDI-outputting SAMgurdy by [Sam Palmer], which we sadly missed covering (though we did feature a MIDI-gurdy a few years back) but this boombox does far more than just MIDI samples. In a sentence no one ever thought would be penned, this instrument puts a Eurorack on a Hurdy-Gurdy for the ultimate synthwave bardcore mashup. There’s an analog synth, there’s a drum machine, there’s modularity to do whatever [Rory] should desire. There are also sixteen sampled instruments available at the push of a button, including multiple analog Hurdy-Gurdies.

It is, as [Rory] says, “a gig in a box”. There’s no point trying to describe it all in words: it really must be heard to be believed, so check out the demo video embedded below, and if you’re hankering for more info, he produced a fifteen minute in-depth video and if you can’t get enough of the sound, here’s a demo with all 16 sampled instruments. We’re pretty sure one of them is the Sega soundfont, and the 8-bit samples are absolutely GameBoy.

How, exactly, we fell in love with the hurdy-gurdy has fallen into mystery, but we’ve been filling up the hurdy-gurdy tag lately, on your suggestions. This one is thanks to a tip from [Physics Dude] in a comment– thanks for that, by the way– and the tips line remains open if the internet has not finally been scoured of all content both hurdy and gurdy.

Continue reading “Hurdy-posting Continues With The Balfolk Boombox, A Synth Gurdy” →

The Cantareel Is Hurdy-Guitar Turned Inside Out

July 12, 2025 by Tyler August 14 Comments

Sometimes, all you need to make something work is to come at it from a different angle from anyone else — flip the problem on its head, so to speak. That’s what [Keizo Ishibashi] did to create his Cantareel, a modified guitar that actually sounds like a hurdy-gurdy.

We wrote recently about a maker’s quest to create just such a hybrid instrument, and why it ended in failure: pressing strings onto the fretboard also pushed them tighter to the wheel, ruining the all-important tension. To recap, the spinning wheel of a hurdy-gurdy excites the strings exactly like a violin bow, and like a violin bow, the pressure has to be just right. There’s no evidence [Keizo Ishibashi] was aware of that work, but he solved the problem regardless, simply by thinking outside the box — the soundbox, that is.

Unlike a hurdy-gurdy, the Cantareel keeps its wheel outside the soundbox. The wheel also does not rub directly upon the strings: instead, it turns what appears to be a pair of o-rings. Each rosined o-ring bows 2 of the guitar’s strings, giving four strings a’ singing. (Five golden rings can only be assumed.) The outer two strings of this ex-six-string are used to hold the wheel assembly in place by feeding through holes on the mounting arms. The guitar is otherwise unmodified, making this hack reversible.

It differs from the classic hurdy-gurdy in one particular: on the Cantareel, every string is a drone string. There’s no way to keep the rubber rings from rubbing against the strings, so all four are always singing. This may just be the price you pay to get that smooth gurdy sound out of a guitar form factor. We’re not even sure it’s right to call it a price when it sounds this good.

Continue reading “The Cantareel Is Hurdy-Guitar Turned Inside Out” →

Get Roped Into Magnetic Core Memory With This 512 Bit Module

July 11, 2025 by Tyler August 19 Comments

Magnetic Core memory was the RAM at the heart of many computer systems through the 1970s, and is undergoing something of a resurgence today since it is easiest form of memory for an enterprising hacker to DIY. [Han] has an excellent writeup that goes deep in the best-practices of how to wire up core memory, that pairs with his 512-bit MagneticCoreMemoryController on GitHub.

Magnetic core memory works by storing data inside the magnetic flux of a ferrite ‘core’. Magnetize it in one direction, you have a 1; the other is a 0. Sensing is current-based, and erases the existing value, requiring a read-rewrite circuit. You want the gory details? Check out [Han]’s writeup; he explains it better than we can, complete with how to wire the ferrites and oscilloscope traces to explain why you want to wiring them that way. It may be the most complete design brief to be written about magnetic core memory to be written this decade.

This little memory pack [Han] built with this information is rock-solid: it ran for 24 hours straight, undergoing multiple continuous memory tests — a total of several gigabytes of information, with zero errors. That was always the strength of ferrite memory, though, along with the fact you can lose power and keep your data. In in the retrocomputer world, 512 bits doesn’t seem like much, but it’s enough to play with. We’ve even featured smaller magnetic core modules, like the Core 64. (No prize if you guess how many bits that is.) One could be excused for considering them toys; in the old days, you’d have had cabinets full of these sorts of hand-wound memory cards.

Magnetic core memory should not be confused with core-rope memory, which was a ROM solution of similar vintage. The legendary Apollo Guidance Computer used both.

We’d love to see a hack that makes real use of these pre-modern memory modality– if you know of one, send in a tip.