It’s Hard To Make A (Good) Oscillator

November 22, 2025 by 1 Comment

There’s more to making an oscillator than meets the eye, and [lcamtuf] is here with a good primer on the subject. It starts with the old joke that if you need an oscillator it’s best to try to make an amplifier instead, but of course the real point here is to learn how to make not just a mere oscillator, but a good oscillator.

He does this by taking the oscillator back to first principles and explaining positive feedback on an amplifier, before introducing the Schmitt trigger, an RC circuit to induce a delay, and then phase shift. These oscillators are not complex circuits by any means, so understanding their principles should allow you to unlock the secrets of oscillation in a less haphazard way than just plugging in values and hoping.

Oscillation is a subject we’ve taken a deep dive into ourselves here at Hackaday, should you wish to learn any more. Meanshile [lcamtuf] is someone we’ve heard from here before, with a comparative review of inexpensive printed circuit board manufacturers.

Microsoft Open Sources Zork I, II And III

November 21, 2025 by 7 Comments

The history of the game Zork is a long and winding one, starting with MUDs and kin on university mainframes – where students entertained themselves in between their studies – and ending with the game being ported to home computers. These being pathetically undersized compared to even a PDP-10 meant that Zork got put to the axe, producing Zork I through III. Originally distributed by Infocom, eventually the process of Microsoft gobbling up game distributors and studies alike meant that Microsoft came to hold the license to these games. Games which are now open source as explained on the Microsoft Open Source blog.

Although the source had found its way onto the Internet previously, it’s now officially distributed under the MIT license, along with accompanying developer documentation. The source code for the three games can be found on GitHub, in separate repositories for Zork I, Zork II and Zork III.

We previously covered Zork’s journey from large systems to home computers, which was helped immensely by the Z-machine platform that the game’s code was ported to. Sadly the original games’s MDL code was a bit much for 8-bit home computers. Regardless of whether you prefer the original PDP-10 or the Z-machine version on a home computer system, both versions are now open sourced, which is a marvelous thing indeed.

How To Use That Slide Rule

November 21, 2025 by 3 Comments

You have that slide rule in the back of the closet. Maybe it was from your college days. Maybe it was your Dad’s. Honestly. Do you know how to use it? Really? All the scales? That’s what we thought. [Amen Zwa, Esq.] not only tells you how slide rules came about, but also how to use many of the common scales. You can also see his collection and notes on being a casual slide rule collector and even a few maintenance tips.

The idea behind these computing devices is devilishly simple. It is well known that you can reduce a multiplication operation to addition if you have a table of logarithms. You simply take the log of both operands and add them. Then you do a reverse lookup in the table to get the answer.

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Schematic of a voltage divider

Making Actually Useful Schematics In KiCad

November 21, 2025 by 6 Comments

[Andrew Greenberg] has some specific ideas for how open-source hardware hackers could do a better job with their KiCad schematics.

In his work with students at Portland State University, [Andrew] finds his students both reading and creating KiCad schematics, and often these schematics leave a little to be desired.

To help improve the situation he’s compiling a checklist of things to be cognisant of when developing schematics in KiCad, particularly if those schematics are going to be read by others, as is the hope with open-source hardware projects.

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Wiring Up The Railway, All The Live-Long Day

November 21, 2025 by 8 Comments

For those of you who haven’t spent time in North America around this time of year, you may be unaware of two things: one, the obligatory non-stop loop of “All I Want For Christmas Is You” retail workers are subjected to starting November first, and two: there is a strong cultural association between Christmastime and model railroading that may not exist elsewhere. That may down to childhood memories of when we got our first trainsets, or an excellent postwar marketing campaign by Lionel. Either way, now that Mariah Carey is blaring, we’re thinking about our holiday track layouts. Which makes this long presentation on Wiring for Small Layouts by [Chicago Crossing Model Railroad] quite timely.

There are actually three videos in this little course; the first focuses mostly on the tools and hardware used for DCC wiring (that’s Digital Command Control), which will be of less interest to our readers– most of you are well aware how to perform a lineman’s splice, crimp connectors onto a wire, and use terminal blocks.

The second two videos are actually about wiring, in the sense of routing all the wires needed for a modern layout– which is a lot more than “plug the rheostat into the tracks in one spot” that our first Lionel boxed set needed. No, for the different accessories there are multiple busses at 5V, 12V and 24V along with DCC that need to be considered. Unsurprisingly enough given those voltages, he starts with an ATX power supply and breaks out from there.

Even if you’re not into model railroading, you might learn something from these videos if you haven’t done many projects with multiple busses and wire runs before. It’s far, far too easy to end up with a rats nest of wires, be they DCC, I2C or otherwise. A little planning can save some big headaches down the line, and if this is a new skill for you [Chicago Crossing Model Railroad] provides a good starting point for that planning. Just skip ahead a couple minutes for him to actually start talking if you don’t want the musical cliff notes montage at the start of the videos.

If you don’t have any model trains, don’t worry, you can 3D print them.  Lack of room isn’t really an excuse.

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Commodore’s Most Popular Computer Gets DOOM-style Shooter

November 21, 2025 by 37 Comments

When people talk about the lack of a DOOM being the doom Commodore home computers, they aren’t talking about the C64, which was deep into obsolescence when demon-slaying suddenly became the minimal requirement for all computing devices. That didn’t stop [Kamil Wolnikowski] and [Piotr Kózka] from hacking together Grey a ray-cast first-person shooter for the Commodore 64.

Grey bares more than a passing resemblance to id-software’s most-ported project. It apparently runs at 16 frames per second on a vanilla C64 — no super CPU required. The secret to the speedy game play is the engine’s clever use of the system’s color mapping functionality: updating color maps is faster than redrawing the screen. Yeah, that makes for rather “blockier” graphics than DOOM, but this is running on a Commodore 64, not a 386 with 4 MB of RAM. Allowances must be made. Come to think of it, we don’t recall DOOM running this smooth on the minimum required hardware — check out the demo video below and let us know what you think.

The four-level demo currently available is about 175 kB, which certainly seems within the realms of possibility for disk games using the trusty 1541. Of course nowadays we do have easier ways to get games onto our vintage computers.

If you’re thinking about Commodore’s other home computer, it did eventually get a DOOM-clone. Continue reading “Commodore’s Most Popular Computer Gets DOOM-style Shooter” →

Hackaday Podcast Episode 346: Melting Metal In The Microwave, Unlocking Car Brakes And Washing Machines, And A Series Of Tubes

November 21, 2025 by No comments

Wait, what? Is it time for the podcast again? Seems like only yesterday that Dan joined Elliot for the weekly rundown of the choicest hacks for the last 1/52 of a year. but here we are. We had quite a bit of news to talk about, including the winners of the Component Abuse Challenge — warning, some components were actually abused for this challenge. They’re also a trillion pages deep over at the Internet Archive, a milestone that seems worth celebrating.

As for projects, both of us kicked things off with “Right to repair”-adjacent topics, first with a washing machine that gave up its secrets with IR and then with a car that refused to let its owner fix the brakes. We heated things up with a microwave foundry capable of melting cast iron — watch your toes! — and looked at a tiny ESP32 dev board with ludicrously small components. We saw surveyors go to war, watched a Lego sorting machine go through its paces, and learned about radar by spinning up a sonar set from first principles.

Finally, we wrapped things up with another Al Williams signature “Can’t Miss Articles” section, with his deep dive into the fun hackers can have with the now-deprecated US penny, and his nostalgic look at pneumatic tube systems.

Download this 100% GMO-free MP3.

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