Kritik sah

With us chafing at time zones and daylight saving time (DST) these days, it can be easy to forget how much more confusing things were in the late 19th century. Back then few areas had synchronized their clocks to something like Greenwich Mean Time (GMT) or other standards like London time or Paris time, with everyone instead running on local time determined by as solar time. This created a massive headache for the railways, as they somehow had to make their time schedules work across what were effectively hundreds of tiny time zones while ensuring that passengers got on their train on time. In a recent video [The Tim Traveller] explains how the creation of so-called Railway time sort-of solved this in France. As railroads massively expanded across the world by the 1850s and travel times dropped rapidly, this concept of Railway time was introduced from the US to Europe to India, creating effectively a railway-specific time zone synchronized to e.g. London time in the UK and Paris ti...

Frequency! It’s an important thing to measure, which is why [Jacques Pelletier] built a frequency counter some time ago. The four-function unit is humble , capable, and also an entry into our 2025 One Hertz Challenge! The build began “a long while ago when electronic parts were still available in local stores,” notes Jacques, dating the project somewhat. The manner of construction, too, is thoroughly old-school. The project case and the sweet red digits are both classic, but so is what’s inside. The counter is based around 4553 BCD counter chips and 4511 decoder ICs. Laced together, the logic both counts frequency in binary-coded decimal and then converts that into the right set of signals to drive the 7-segment displays. Sample time is either 1 Hz or 0.1 Hz, which is derived from an 8MHz oscillator. It can act as a frequency meter, period meter, chronometer, or a basic counter. The whole build is all raw logic chips, there are no microprocessors or microcontrollers involved. It jus...

When film all came in rolls, it was fairly easy to play with the frame of the image. Companies like Hasselblad (and many others) made camera backs that would expose longer strips of 35 mm film to create stunning panoramic images in one single shot. [snappiness] wanted to bring that style of camera into the digital age, and ended up with a 2-in-1 Sony-based frankencamera . Sensors just aren’t readily available in the wide aspect ratio [snappiness] was looking for, and even if they were, bare sensors are hugely expensive compared to consumer cameras. Lacking the budget for high-res scientific CMOS, [snappiness] did what any of us would do, and hacked two Sony A7ii full-frame mirrorless cameras together to get a combined 24x72mm sensor frame. Conceptually, the hack is really very simple: a 3D print acts like a T-fitting, with the two cameras held parallel off the arms of the T and the lens making the shaft. Inside, the only optics are a pair of mirrors serving as a beam splitter. Each ...

Sometimes, there are too many choices in this world. My benchtop function generator can output a sine, square, or saw wave anywhere from 0.01 Hz up to 60 MHz? Way too many choices. At least, that’s what we suspect [Phil Weasel] was thinking when he built this Analog 1 Hz Sinewave Generator . A KiCad rendering of [Phil]’s design [Phil]’s AWG (which in this case stands for A nything as long as it’s a 1 Hz sine  W ave  G enerator) has another unique feature — it’s built (almost) entirely with op-amps. A lot of op-amps (37, by our count of the initial schematic he posted). His design is similar to a Phased Locked Loop (PLL) and boils down to a triangle wave oscillator. While a 1 Hz triangle wave would absolutely satisfy judges of the One Hertz Challenge, [Phil] had set out to make a sine wave. Using a feedback loop and some shaping/smoothing tricks (and more op-amps), he rounded off the sharp peaks into a nice smooth sine wave. Sometimes we make things much more complicated t...

WarGames fans, rejoice: [Nick Bild] has rebooted WOPR for real. In his latest hack, the Falcon, he recreates the iconic AI from the 1983 film using a Raspberry Pi 400, a vintage SP0256-AL2 speech chip from General Instrument, and Google’s Gemini LLM. A build to bring us back to the Reagan-era. Where most stop at visual homage, this one simulates true interaction. The Python script acts as dungeon master for Gemini 2.5 Flash, guiding it to roleplay as the WOPR computer. Keypress sounds click-clack in synchrony with every input. Gemini replies are filtered into allophones, through GI-Pi, [Nick]’s own Python library. The SP0256 then gives it an eerily authentic robotic voice, straight out of 1983. [Nick] himself is no unfamiliar name to Hackaday. Back in 2020, he hosted a Hack Chat where he talked us through getting from ideas to prototype builds. He practices what he preaches, since he carried out projects like a breadboard 6502 computer , home-automation controlling AI sunglasses ...

In the early 00s there was a tiny moment before the widespread adoption of mobile broadband, after the adoption of home WiFi, and yet before the widespread use of encryption. For this brief time a unique practice arose called wardriving — where people would drive around, document, and use these open wireless networks. Although the pursuit has diminished with the rise of mobile broadband and WPA encryption, there are still a few use cases for the types of hardware a wardriver would have used. [arduinocelentano] recently built a Wi-Fi strength monitor in this style but with a unique theme . The Silly Space Invaders Dashboard (SSID) uses an ESP8266 to periodically scan for WiFi networks and makes a record of all of the ones it discovers. From there it takes a look at the signal strength that it receives and groups them into a few classes. For each class it assigns a Space Invaders -themed sprite corresponding to signal strength, with the strongest ranked at the top for quick and easy ...

Over on his YouTube channel the vivacious [Stephen Hawes] tells us that we never need to buy solder stencils again ! A big claim! And he is quick to admit that his printed solder paste isn’t presently quite as precise as solder stencils, but he is reporting good success with his technique so far. [Stephen] found that he could print PCBs with his fiber laser , populate his boards with his LumenPnP , and reflow with his oven, but… what about paste? [Stephen] tried making stencils, and in his words: “it sucked!” So he asked himself: what if he didn’t need a stencil? He built a Gerber processing, G-code generating, machine-vision implemented… website. The LumenPnP Pasting Utility: https://paste.opulo.io/ The WebAssembly running in the Chrome tab itself connects to the LumenPnP and performs the entire pasting job automatically, with machine-vision fiducial calibration. Automatic alignment with fiducials was critical to the project’s feasibility, and he achieved it using machine-visi...

In the retrocomputing world, [DosDude1] is a name spoken with more than a little respect. He’s back again with a long-awaited hack for PowerPC Macintosh: soldered RAM upgrades ! [DosDude1] is no stranger to soldering his way to more storage– upgrading the SSD on an M4 Mac Mini, or doubling  the VRAM on an old GPU . For a PPC Mac, though, it is not enough just to solder more RAM onto the board; if that’s all it was, we’d have been doing it 20 years ago. Once the RAM is in place, you have to have some way to make sure the computer knows the RAM is in place. For a WinTel machine, getting that information to the BIOS can be as easy as plugging in the right resistors. This is part of the BootROM dump. It’s easy to see why nobody figured this out before. PowerPC Macintoshes don’t have BIOS, though. Instead, what’s required is a hack to modify the machine’s BootROM, and write an edited version back into the motherboard’s EEPROM. No one knew how to make that work, until now. [DosDu...

From the outside, iron meteorites tend to look like formless, rusted lumps of metal, which is why museums often polish and etch sections to show their interior structure. This reveals their Widmanstätten patterns, a latticework structure of parallel iron-nickel intermetallic crystals which forms over millions of years of very slow solidification. Inspired by this, [Electron Impressions] created his own metal composition which forms similar patterns on a much-faster-than-geological time scale. Witmanstätten patterns form when a meteorite colliding with a planet launches molten iron and nickel into space, where they very slowly solidify. As the mixture cools, it first forms a stable phase called Taenite, then begins to precipitate another phase called Kamacite. Kamacite forms needle-shaped crystals, which when polished show up against the Taenite background. However, such needle-shaped growth only becomes noticeable at a cooling rate of a few degrees per million years, so it’s not rea...

Our hacker [Wil Carver] has sent in his submission for the One Hertz Challenge: Precise Time Ref via 1 Pulse-Per-Second GPS Signal . This GPS Disciplined Oscillator (GPSDO) project uses a Piezo 2940210 10 MHz crystal oscillator which is both oven-controlled (OCXO) and voltage-controlled (VCXO). The GPSDO takes the precision 1 Pulse-Per-Second (PPS) GPS signal and uses it to adjust the 10 MHz crystal oscillator until it repeatedly produces 10,000,000 cycles within one second. [Wil] had trouble finding all the specs for the 2940210, particularly the EFC sensitivity (S), so after doing some research he did some experiments to fill in the blanks. You can get the gory details in his notes linked above. In a Voltage-Controlled Crystal Oscillator (VCXO), the EFC pin is the tuning-voltage input. EFC stands for Electronic Frequency Control. [Wil] found that he needed to push the EFC up to around 4.34V in order to get 10 MHz output, which is a bit out of spec, usually the center of the ran...

PCB business cards are a creative way to show your tech skills while getting your name out there. This take on a PCB business card , sent in by [VCC], tackles one of the big challenges with them: making them in such a way that they are cheap enough to not feel bad about handing them out. These cards plug into a USB port for power and have over a dozen small LEDs that light up the stars on the front, and a small buzzer that can play over ten minutes of cracktro music. To keep the cost down, [VCC] went with an ATtiny1616 microcontroller costing under 50 cents and still having plenty of outputs to drive the buzzer and LEDs. The final per-unit cost prior to shipping came out to only 1.5 euros, enabling them to be handed out without worrying about breaking the bank. To aid in the assembly of the cards, [VCC] 3D printed a jig to apply material to the back of the USB connector, building up its thickness to securely fit in the USB port. He also wrote a small script for assembly-line progra...

The HP 115BR is not one of the most well-known products from Hewlett-Packard. And yet, it was remarkably important nonetheless. This hardware once synced time around the world. Now, for our 2025 One-Hertz Challenge, [curiousmarc] has taken on the job of restoring it.  The HP 115BR itself was not used alone, but in concert with the HP5060A atomic clock. The latter would output a 100 KHz reference output. It was the job of the HP 115BR to divide this frequency down to provide a superbly accurate 1-second tick. The example on [curiousmarc]’s bench showed up in poor shape. It was “very broken,” and he reported that it had also previously been hacked to some degree. However, he has been able to restore it to proper functionality, including the special modification for continuous tick adjustment, as used in the 1964 flying atomic clock experiment. He was even able to sync it to NIST’s current atomic clock signal from Fort Collins using the WWW radio signal. We’ve seen plenty of old ...

[Stoppi] always has interesting blog posts and videos, even when we don’t understand all the German in them. The latest? Computer simulation of wave propagation ( Google Translate link ), which, if nothing else, makes pretty pictures that work in any language. Check out the video below. Luckily, most browsers will translate for you these days, or you can use a website. We’ve seen waves modeled with springs before, but between the explanations and the accompanying Turbo Pascal source code, this is worth checking out. We can’t explain it better than [Stoppi] who writes: The model consists of individual atoms with the mass m, which are connected to each other by springs with the spring constant k. To start, I deflect the first atom sinusoidally. According to this, the individual atoms obey Newton’s equation of motion F = m·a, whereby Hook’s spring law F = k·Δl is used for the force F. I solved these differential equations iteratively using the Euler method. The movement of the atom...

Although firmly entrenched in the cultural zeitgeist now, the skateboard wasn’t always a staple of popular culture. It had a pretty rocky start as surfers jankily attached roller skating hardware to wooden planks searching for wave-riding experiences on land. From those rough beginnings it still took decades of innovation until Rodney Mullen adapted the ollie for flatground skating before the sport really took off. Skateboard hardware is quite elegant now too; the way leaning turns the board due to the shape of the trucks is immediately intuitive for even the most beginner riders, and bearing technology is so high-quality and inexpensive now that skateboard hardware is a go-to parts bin grab for plenty of other projects like this plasma cutter modification . [The Fabrication Series]’s plasma cutter is mounted to a CNC machine, allowing for many complex cuts in much less time than it would take to do by hand. But cutting tubes is a more complicated endeavor for a machine like this. Th...

PAHT-CF part printed at 45 degrees, with reinforcing bolt, post-failure. (Credit: Functional Print Friday, YouTube) The good part about FDM 3D printing is that there are so many different filament types and parameters to choose from. This is also the bad part, as it can often be hard to tell what impact a change has. Fortunately we got destructive testing to provide us with some information here. Case in point [Functional Print Friday] on YouTube recently testing out a few iterations of a replacement part for a car. The original part was in ABS, printed horizontally in a Bambu Lab FDM printer, which had a protruding element snapped off while in use. In addition to printing a replacement in carbon fiber-reinforced nylon ( PAHT-CF , i.e. PA12 instead of the typical PA6), the part was now also printed at a 45° angle. To compare it with the original ABS filament in a more favorable way, the same part was reprinted at the same angle in ABS. Another change was to add a machine screw t...

Wall clocks! Are they very accurate? Well, sometimes they are, and sometimes they lose minutes a day. If you’ve got one that needs calibrating, you might like this device from [Lauri Pirttiaho]. Most cheap wall clocks use very similar mechanisms based around the Lavet-type stepper motor . These are usually driven by a chip-on-board oscillator that may or may not be particularly accurate. [Lauri] desired a way to tune up these cheap clocks by using GPS-level timing accuracy. Thus began a project based around a CY8KIT evaluation board from Cypress. The microcontroller is paired with a small character LCD as a user interface, and hooked up to a cheap GPS module with an accurate 1-pulse-per-second (1PPS) timing output. The concept is simple enough. Clock drift is measured by using counters in the microcontroller to compare the timing of the GPS 1PPS output and the pulses driving the Lavet-type stepper motor. The difference between the two can be read off the device, and used to determin...

As Earthlings, most of us don’t spend a lot of extra time thinking about the gravity on our home planet. Instead, we go about our days only occasionally dropping things or tripping over furniture but largely attending to other matters of more consequence. When humans visit other worlds, though, there’s a lot more consideration of the gravity and its effects on how humans live and many different ways of training for going to places like the Moon or Mars. This gravity simulator, for example, lets anyone experience what it would be like to balance an object anywhere with different gravity from Earth’s . The simulator itself largely consists of a row of about 60 NeoPixels, spread out in a line along a length of lightweight PVC pipe. They’re controlled by an Arduino Nano which has a built-in inertial measurement unit, allowing it to sense the angle the pipe is being held at as well as making determinations about its movement. A set of LEDs on the NeoPixel strip is illuminated, which simul...

Most of you know how an NFC tag works. The reader creates an RF field that has enough energy to power the electronics in the tag; when the tag wakes up, two-way communication ensues. We’re accustomed to blank tags that can be reprogrammed, and devices like the Flipper Zero that can emulate a tag. In between those two is [MCUer]’s power-free tag emulator , a board which uses NFC receiver hardware to power a small microcontroller that can run emulation code. The microcontroller in question is the low-power CW32L010 from Wuhan Xinyuan Semiconductor, a Chinese part with an ARM Cortex M0+ on board. Unfortunately, that’s where the interesting news ends, because all we can glean from the GitHub repository is a PCB layout. Not even a circuit diagram, which we hope is an unintended omission rather than deliberate. It does, however, lend itself to the fostering of ideas, because if this designer can’t furnish a schematic, then perhaps you can. It’s not difficult to make an NFC receiver , so p...

Sad breaking news late this Sunday afternoon of the passing of nerd icon Tom Lehrer at 97 . Coming up through the culture, knowing at least a few of Tom’s ditties, preferably “The Elements” or “Poisoning Pigeons in the Park,” was as essential to proving one’s bona fides as committing most Monty Python bits to memory. Tom had a way with words that belied his background as a mathematician, spicing his sarcastic lyrics with unusual rhymes and topical references that captured the turbulence of the late 50s and early 60s, which is when he wrote most of his well-known stuff. First Ozzy, then Chuck Mangione, now Tom Lehrer — it’s been a rough week for musicians. Here we go again. It looks like hams have another spectrum grab on their hands , but this time it’s the popular 70-cm band that’s in the crosshairs. Starlink wannabe AST SpaceMobile, which seeks to build a constellation of 248 ridiculously large communication satellites to offer direct-to-device service across the globe, seeks a su...

This eye-catching entry to the One Hertz Challenge pairs vintage LED indicators with a modern RPi board to create a one-of-a-kind clock. The RPI TinynumberHat9 by [Andrew] brings back the beautiful interface from high end electronics of the past. This project is centered around the red AL304 and green ALS314V 7-segment display chips. These 7-segment displays were produced in the 1970s and 1980s in the Soviet Union; you can still find them, but you’ll have to do some digging as they are only becoming more rare. [Andrew] included the data sheet for these which was a good find, it is written in Russian but doesn’t hold any surprises, these tiny LEDs typically forward current is 5mA at 2V. One of the things that jumps out about these LEDs is the gold leads, a sure sign of being a high-end component of their day. When selecting a driving chip for the LEDs, [Andrew] looked at the MAX7219 and HT16K33; he settled on the HT16K33 as it supports I2C as well as allows the easy addition of butt...

You can buy all kinds of conventional clocks that have hands and numbers for easy reading. Or, like [Fabio Ricci], you could build yourself something a little more esoteric, like this neat shadow clock . The heart of the build is an ESP8266 microcontroller, which gets the current time via Wi-Fi by querying an NTP time server. It also uses a DS3231 real-time clock module as a backup, keeping accurate time even when a network connection is unavailable. Time is displayed via a 60-pixel ring of WS2812B addressable LEDs. These 60 LEDs correspond to the usual per-minute graduations that you would find on a regular clock. Current hour is displayed by lighting the corresponding LED red, while minutes are shown in blue and seconds in white. It’s called a “shadow clock” because of its method of activation. IR distance sensors are used to activate the time display when a hand or finger is placed near the clock. As Fabio puts it, “shadow play” will make the clock display the time. Otherwise, it...