Kritik sah

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. For a simple example, you know the (base 10) log of 10 is 1 and the log of 1000 is 3. Adding those gives you 4, and, what do you know, 10 4 is 10,000, the correct answer. That’s easy when you are working with numbers like 10 and 1000 with base 10 logarithms, but it works with any ...

[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. In the video and in his checklist he runs us through some of the considerations, covering: visual design best practices; using schematic symbols rather than packages; nominating part values; specific types of circuit gotchas; Design for Test; Design for Fail; electric rule checks (ERC); manufacturer (MFR), part number (MPN), and datasheet annotations for Bill of Materials (BOM); and things to check at the end of a design iteration,...

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 wi...

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 G rey 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...

If you’ve ever used an NE602 or similar IC to build a radio, you might have noticed that the datasheet has a “gilbert cell” mixer. What is that? [Electronics for the Inquisitive Experimenter] explains them in a recent video. The gilbert cell is a multiplier, and multiplying two waveforms will work to mix them together. At the heart of the gilbert cell is essentially three differential amplifiers that share a common current source. The video shows LTSpice simulations of the circuits as he explains them. One reason these work well on ICs is that they require very closely-matched transistors. In real life, it is hard to get transistors that match exactly. But when they are all on the same slab of silicon, it is fairly straightforward. What we really like is that after simulating and explaining the circuit, he explains why multipliers mix signals, then builds a real circuit on the bench using discrete transistors and matched transistor arrays. There is a bit of trigonometry in the ex...

Once upon a time, owning a calculator watch was the epitome of cool. Well, for a very specific subset of the population with our own definition of “cool” anyway. The only thing cooler than wearing a calculator watch? Making a calculator watch, of course! If you do it as part of developing your own SDK for a popular RISC V microcontroller, all the better. That’s what [Miroslav Nemecek] did with his Antcalc watch , which is one of the demo projects for the CH32Lib SDK , which is currently under development at version 0.35 as this is written. It appears as though the solid core wire on the back of the homemade PCB is used to hold the watch band, a nice little hack. As you might guess, CH32LibSDK is targeting the super-cheap CH32 series of RISC V microcontrollers. Perhaps because the SDK is so early in development, there’s not much documentation outside of the example projects. The examples are all worth looking at, but our tipster wanted us to cover the Antcalc calculator watch speci...

When you’re like [Wes] from  Watch Wes Work fame, you don’t have a CNC machine hoarding issue, you just have a healthy interest in going down CNC machine repair rabbit holes. Such too was the case with a recently acquired 2001 Milltronics ML15 lathe , that at first glance appeared to be in pristine condition. Yet despite – or because of – living a cushy life at a college’s workshop, it had a number of serious issues, with a busted Z-axis drive board being the first to be tackled. The Glentek servo board that caused so much grief. (Credit: Watch Wes Work, YouTube) The identical servo control board next to it worked fine, so it had to be an issue on the board itself.  A quick test showed that the H-bridge IGBTs had suffered the typical fate that IGBTs suffer, violently taking out another IC along with them. Enjoyably, this board by one Glentek Inc. did the rebranding thing of components like said IGBTs, which made tracking down suitable replacements an utter pain that was ...

It’s likely that Hackaday readers have among them a greater than average number of people who can name one special thing they did on September 23rd, 2002. On that day a new web browser was released, Phoenix version 0.1, and it was a lightweight browser-only derivative of the hugely bloated Mozilla suite. Renamed a few times to become Firefox, it rose to challenge the once-mighty Microsoft Internet Explorer, only to in turn be overtaken by Google’s Chrome. Now in 2025 it’s a minority browser with an estimated market share just over 2%, and it’s safe to say that Mozilla’s take on AI and the use of advertising data has put them at odds with many of us who’ve kept the faith since that September day 23 years ago. Over the last few months I’ve been actively chasing alternatives , and it’s with sadness that in November 2025, I can finally say I’m Firefox-free. Just What Went Wrong? Browser market share, 2009 to 2025. Statcounter, CC BY-SA 3.0 . It was perhaps inevitable that Firefox w...

Whenever there’s a superlative involved, you know that degree of optimization has to leave something else on the table. In the case of [PegorK]’s f32, the smallest ESP32 dev board we’ve seen, the cost of miniaturization is GPIO. There’s only one GPIO pin broken out, and it’s pre-wired to an LED. That’s the bad news, and depending on what you want an ESP32 for, it might not phase you at all. What is impressive here, if not the number of I/O pins, is the size of the board: at 9.85 mm x 8.45 mm barely overhangs the USB-C socket that takes up one side of the board. Pegor provides this helpful image in the readme so you know what you’re getting into with the 01005 resistors. In order to get the ESP32-C3FH4 onto such a tiny board, all of the other support hardware had to be the smallest possible sizes– including resistors in 01005. If you don’t speak SMD, one could read that number code as “oh god too small” — at 0.4 mm x 0.2 mm it’s as minuscule as you’ll find– and [Pegor] hand solde...

When Stranger Things premiered in 2016, it was a cultural force. Foreign DJs gushed over the lush 80s soundtrack, fashionistas loved the clothing, and the world became obsessed with the idea of using Christmas lights to communicate across material planes. [kyjohnso] has recreated that experience with the technology of today. If you haven’t watched the show — Joyce Byers is trying to communicate with her son Will, who just so happens to be stuck in another plane of existence called the Upside Down. She screams questions at her living room wall, upon which hangs a series of Christmas lights, marked with the letters A to Z. Will is able to communicate back by causing the lights to flash, one letter at a time. This build works a little differently. You basically type a message into a terminal on a Raspberry Pi, and it gets sent to a large language model—namely, the Claude API. The response from Claude (or Will Byers, if you’re imagining) is then flashed out on a WS2812B set of LED Chr...

This week Jonathan chats with Kevin, Colin, and Curtis about Cataclysm: Dark Days Ahead ! It’s a rogue-like post-apocalyptic survival game that you can play in the terminal, over SSH if you really want to! Part of the story is a Kickstarter that resulted in a graphics tile-set. And then there’s the mods! https://cataclysmdda.org/ https://github.com/CleverRaven/Cataclysm-DDA Did you know you can watch the live recording of the show right on our YouTube Channel ? Have someone you’d like us to interview? Let us know, or have the guest contact us! Take a look at the schedule here . Direct Download in DRM-free MP3. If you’d rather read along, here’s the transcript for this week’s episode . Places to follow the FLOSS Weekly Podcast: Spotify RSS Theme music: “Newer Wave” Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 4.0 License from Blog – Hackaday https://ift.tt/xOsMo9v

We aren’t here to praise the penny, but rather, to bury it. The penny, and its counterparts, have been vanishing all around the world as the cost of minting one far outweighs its value. But hackers had already lost a big asset: real copper pennies, and now even the cheaply made ones are doomed to extinction. If you check your pockets and find a pre-1982 penny, it’s almost all copper. Well, 95% of its slightly-more-than-3-gram heft is pure copper. Since then, the copper penny’s been a fraud, weighing 2.5 g and containing only a 2.5% copper plate over a zinc core. During WWII, they did make some oddball steel pennies, but that was just a temporary measure. Penny Science If you are a certain age, you might remember building a “voltaic pile.” These primitive batteries use pennies, cardboard soaked in vinegar, and aluminum foil. Granted, it wasn’t very practical, so raiding your couch for change to make a battery was never really practical, but it was a fun science experiment. There ar...

“Build a better mousetrap and the world will beat a path to your door,” so goes the saying, but VHS beat Betamax and the world hasn’t been the same since. In any case, you might not get  rich building a better mousetrap, but you can certainly create something more humane than the ol’ spring’n’snap , as [nightcustard] demonstrates. The concept is the same as many humane mousetraps on the market. The mouse is lured into a confined cavity with the use of bait, and once inside, a door closes to keep the mouse inside without injuring it. [nightcustard] achieved this by building a plastic enclosure with plenty of air holes, which is fitted with a spring-loaded door. When a mouse walks through an infra-red break beam sensor, a Raspberry Pi Pico W triggers a solenoid which releases the door, trapping the mouse inside. This design was chosen over a passive mechanical solution, because [nightcustard] noted that mice in the attic were avoiding other humane traps with obvious mechanical tri...

Perhaps the biggest hurdle to starting a home blacksmithing operating is the forge. There’s really no way around having a forge; somehow the metal has to get hot enough to work. Although we might be imagining huge charcoal- or gas-fired monstrosities, [Shake the Future] has figured out how to use an unmodified, standard microwave oven to get iron hot enough to melt and is using it in his latest video to cast real, working tools with it . In the past, [Shake the Future] has made a few other things with this setup like an aluminum pencil with a graphite core . This time, though, he’s stepping up the complexity a bit with a working tool. He’s decided to build a miniature bench vice, which uses a screw to move the jaws. He didn’t cast the screw, instead using a standard size screw and nut, but did cast the two other parts of the vice. He first 3D prints the parts in order to make a mold that will withstand the high temperatures of the molten metal. With the mold made he can heat up the i...

The magnetic loop antenna is a familiar sight in radio amateur circles as a means to pack a high performance HF antenna into a small space. It takes the form of a large single-turn coil made into a tuned circuit with a variable capacitor, and it provides the benefits of good directionality and narrow bandwidth at the cost of some scary RF voltages and the need for constant retuning. As [VK3YE] shows us though, magnetic loops are not limited to HF — he’s made a compact VHF magnetic loop using a tin can . It’s a pretty simple design; a section from the can it cut out and made into a C shape, with a small variable capacitor at the gap. The feed comes in at the bottom, with the feed point about 20 % of the way round the loop for matching. The bandwidth is about 100 MHz starting from the bottom of the FM broadcast band, and he shows us it receiving broadcast, Airband, and 2 meter signals. It can be used for transmitting too and we see it on 2 meter WSPR, but we would have to wonder whethe...

For the Component Abuse Challenge , we asked you to do the wrong thing with electrical parts, but nonetheless come out with the right result. It’s probably the most Hackaday challenge we have run in a long time, and you all delivered! The judging was tight, but in the end three projects rose up to the top, and will each be taking home a $150 DigiKey gift certificate, but that doesn’t mean you shouldn’t give all of the projects a look. So without further ado, let’s check out the winners and all the others that tickled the hacky regions of our judges’ brains. Prize Winners [Miroslav Hancar]’s LED Candles was a shoe-in, at least if you watched the video demo. It presents itself as a simple LED on a round PCB with a coin cell, but then when [Miroslav] lights it with an actual lighter , it starts glowing. (And maybe smoking just a little bit.) He makes both single-LED and quad-LED varieties, and they’re both gems. The component misuse is an old favorite: the diode’s forward voltage ...