Kritik sah

A spectrometer is one of those tools that many of us would love to have, but just can’t justify the price of. Sure there are some DIY options out there, but few of them have the convenience or capability of what’s on the commercial market. [Chris] from Zoid Technology recently found a portable spectrometer complete with Android application for just $150 USD on AliExpress which looked very promising …at least at first. The problem is that the manufacturer, Torch Bearer, offers more expensive models of this spectrometer. In an effort to push users into those higher-priced models, arbitrary features such as data export are blocked in the software. [Chris] first thought he could get around this by reverse engineering the serial data coming from the device (interestingly, the spectrometer ships with a USB-to-serial adapter), but while he got some promising early results, he found that the actual spectrometer data was obfuscated — a graph of the results looked like stacks of LEGOs. Tha...

[Luca Dentella] recently encountered a toy, which was programmed to read different stories aloud based on the figurine placed on top. It inspired him to build an audio device using the same concept , only with music instead of children’s stories. The NFC Music Player very much does what it says on the tin. Present it with an NFC card, and it will play the relevant music in turn. An ESP32 WROOM-32E lives at the heart of the build, which is hooked up over I2S with a MAX98357A Class D amplifier for audio output. There’s also an SD card slot for storing all the necessary MP3s, and a PN532 NFC reader for reading the flash cards that activate the various songs. Everything is laced up inside a simple 3D-printed enclosure with a 3-watt full range speaker pumping out the tunes. It’s an easy build, and a fun one at that—there’s something satisfying about tossing a flash card at a box to trigger a song. Files are on Github for the curious. We’ve featured similar projects before, like the ...

[Jamie] decided to build a generator, and Lego is his medium of choice. Thus was created a fancy levitating generator that turns a stream of air into electricity.  The basic concept is simple enough for a generator—magnets moving past coils to generate electricity. Of course, Lego doesn’t offer high-strength magnetic components or copper coils, so this generator is a hybrid build which includes a lot of [Jamie’s] non-Lego parts. Ultimately though, this is fun because of the weird way it’s built. Lego Technic parts make a very crude turbine, but it does the job. The levitation is a particularly nice touch—the build uses magnets to hover the rotor in mid-air to minimize friction to the point where it can free wheel for minutes once run up to speed. The source of power for this contraption is interesting, too. [Jamie] didn’t just go with an air compressor or a simple homebrew soda bottle tank. Instead, he decided to use a couple of gas duster cans to do the job. The demos are pretty...

Hackers like making clocks, and we like reporting on them around these parts. Particularly if they’ve got a creative mechanism that we haven’t seen before. This fine timepiece from [gooikerjh] fits the bill precisely— it’s a sliding tile clock! The brains of the build is an Arduino Nano ESP32. No, that’s not a typo. It’s basically an ESP32 in a Nano-like form factor. It relies on its in-built WiFi hardware to connect to the internet and synchronize itself with time servers so that it’s always showing accurate time. The ESP32 is set up to control a set of four stepper motors with a ULN2003 IC, and they run the neat time display mechanism. All the custom parts are 3D printed, and the sliding tile concept is simple enough. There are four digits that show the time. Each digit contains number tiles that slide into place as the digit rotates. To increment the digit by one, it simply needs to be rotated 180 degrees by the relevant stepper motor, and the next number tile will slide into pla...

Prototyping is a personal affair, with approaches ranging from dead-bug parts on tinplate through stripboard and protoboard, to solderless breadboards and more. Whichever you prefer, a common problem is that they don’t offer much in the way of solid connections to the outside world. You could use break-out boards, or you could do like [Pakequis] and make a prototyping board with every connector you can think of ready to go . The board features the expected prototyping space in the middle, and we weren’t joking when we said every connector. There are analogue, serial, USB, headers aplenty, footprints for microcontroller boards, an Arduino shield, a Raspberry Pi header, and much more. There will doubtless be ones that readers will spot as missing, but it’s a pretty good selection. We can imagine that with a solderless breadboard stuck in the middle it could be a very useful aid for teaching electronics, and we think it would give more than a few commercial boards a run for their money...

Detecting single photons can be seen as the backbone of cutting-edge applications like LiDAR, medical imaging, and secure optical communication. Miss one, and critical information could be lost forever. That’s where FPGA-based instrumentation comes in, delivering picosecond-level precision with zero dead time. If you are intrigued, consider sitting in on the 1-hour webinar that [Dr. Jason Ball], engineer at Liquid Instruments, will host on April 15th. You can read the announcement here . Before you sign up and move on, we’ll peek into a bit of the matter upfront. The power lies in the hardware’s flexibility and speed. It has the ability to timestamp every photon event with a staggering 10 ps resolution. That’s comparable to measuring the time it takes light to travel just a few millimeters. Unlike traditional photon counters that choke on high event rates, this FPGA-based setup is reconfigurable, tracking up to four events in parallel without missing a beat. From Hanbury-Brown-Twiss ...

The hits just keep coming for the International Space Station (ISS), literally in the case of a resupply mission scheduled for June that is now scrubbed thanks to a heavy equipment incident that damaged the cargo spacecraft. The shipping container for the Cygnus automated cargo ship NG-22 apparently picked up some damage in transit from Northrop Grumman’s Redondo Beach plant in Los Angeles to Florida. Engineers inspected the Cygnus and found that whatever had damaged the container had also damaged the spacecraft, leading to the June mission’s scrub. Mission controllers are hopeful that NG-22 can be patched up enough for a future resupply mission, but that doesn’t help the ISS right now, which is said to be running low on consumables. To fix that, the next scheduled resupply mission, a SpaceX Cargo Dragon slated for an April launch, will be modified to include more food and consumables for the ISS crew. That’s great, but it might raise another problem: garbage. Unlike the reusable Ca...

We use ARM devices in everything from our microcontroller projects to our laptops, and many of us are aware of the architecture’s humble beginnings in a 1980s Acorn Archimedes computer. ARM processors are not the only survivor from the Archimedes though, its operating system has made it through the decades as well. RISC OS is a general purpose desktop operating system for ARM platforms that remains useful in 2025, as well as extremely accessible due to a Raspberry Pi port. No software can stand still though, and if RISC OS is to remain relevant it must move with the times. Thus RISC OS Open, the company behind its development, have launched what they call a Moonshots Initiative , moving the OS away from incremental development towards much bolder steps. This is necessary in order for it to support the next generation of ARM architectures. We like RISC OS here at Hackaday and have kept up to date with its recent developments , but even we as fans can see that it is in part a little d...

Music consumption has followed a trend over the last decade or more of abandoning physical media for online or streaming alternatives. This can present a problem for young children however, for whom a simpler physical interface may be an easier way to play those tunes. Maintaining a library of CDs is not entirely convenient either, so [JakesMD] has created the Yaydio. It’s a music player for kids, that plays music when a card is inserted in its slot . As you might expect, the cards themselves do not contain the music. Instead they are NFC cards, and the player starts the corresponding album from its SD card when one is detected. The hardware is simple enough, an Arduino Nano with modules for MP3 playback, NFC reading, seven segment display, and rotary encoder. The whole thing lives in a kid-friendly 3D printed case. Some thought has been given to easily adding albums and assigning cards to them, making it easy to keep up with the youngster’s tastes. This isn’t the first such kid-fri...

Split keyboards are becoming more popular, but because they’re still relatively niche, they can be rather expensive if you want to buy one. So why not make your own? Sure, you could assemble one from a kit, but why not take a cheap mechanical keyboard, slice it in half and just waves hands connect the two halves back together? If this thought appeals to you, then [nomolk]’s literal hackjob video should not be ignored . Make sure to enable English subtitles for the Japanese-language video. Easy split keyboard tip: just reconnect both halves… (Credit: nomolk, YouTube) In it, the fancy (but cheap) mechanical keyboard with Full RGB functionality is purchased and tested prior to meeting its demise. Although the left side with the cable and controller still works, the right side now needs to be connected, which is where a lot of tedious wires have to be soldered to repair traces. Naturally this will go wrong, so it’s important to take a (sushi) break and admire the sunset before hurl...

The Pomdoro technique of time management has moved on a little from the tomato-shaped kitchen timer which gave it a name, as [Rukenshia] shows us with this nifty ESP32 and e-paper design . It’s relatively simple in hardware terms, being a collection of off-the-shelf modules in a 3D printed case, but the software has a custom interface for the friend it was built for. At its heart is a NodeMCU board and a Waveshare display module, with a rotary encoder and addressable LED as further interface components. A lot of attention has been paid to the different options for the interface, and to make the front end displayed on the screen as friendly and useful as possible. Power comes via USB-C, something that should be available in most working environments here in 2025. We’ve tried a variant on this technique for a while now with varying success, maybe because a mobile phone doesn’t make for as good a timer as a dedicated piece of hardware such as this. Perhaps we should follow this example...

When the AMSAT-OSCAR 7 (AO-7) amateur radio satellite was launched in 1974, its expected lifespan was about five years. The plucky little satellite made it to 1981 when a battery failure caused it to be written off as dead. Then, in 2002 it came back to life. The prevailing theory being that one of the cells in the satellites NiCd battery pack, in an extremely rare event, shorted open — thus allowing the satellite to run (intermittently) off its solar panels. In a recent video by [Ben] on the AE4JC Amateur Radio YouTube channel goes over the construction of AO-7 , its operation, death and subsequent revival are covered, as well as a recent QSO (direct contact). The battery is made up of multiple individual cells. The solar panels covering this satellite provided a grand total of 14 watts at maximum illumination, which later dropped to 10 watts, making for a pretty small power budget. The entire satellite was assembled in a ‘clean room’ consisting of a sectioned off part of a b...

[ombates] shares a step-by-step method for making a conductive bio-string from scratch , no fancy equipment required. She demonstrates using it to create a decorative top with touch-sensitive parts, controlling animations on an RGB LED pendant. To top it off, it’s even biodegradable! The string is an alginate-based bioplastic that can be made at home and is shaped in a way that it can be woven or knitted. Alginate comes primarily from seaweed, and it gels in the presence of calcium ions. [ombates] relies on this to make a goopy mixture that, once extruded into a calcium chloride bath, forms a thin rubbery length that can be dried into the strings you see here. By adding carbon to the mixture, the resulting string is darkened in color and also conductive. There’s no details on what the actual resistance of a segment of this string can be expected to measure, but while it might not be suitable to use as wiring it is certainly conductive enough to act as a touch sensor in a manner simi...

Back in the early 1900s, before calculators lived in our pockets, crunching numbers was painstaking work. Adding machines existed, but they weren’t exactly convenient nor cheap. Enter Vilin Vinson and his Maximal Multi-Divi, a massive multiplication and division table that turned math into an industrialized process. Originally published in Sweden in the 1910’s, and refined over decades, his book was more than a reference. It was a modular calculating instrument, optimized for speed and efficiency. In this video , [Chris Staeker] tells all about this fascinating relic. What makes the Multi-Divi special isn’t just its sheer size – handling up to 9995 × 995 multiplications – but its clever design. Vinson formatted the book like a machine, with modular sections that could be swapped out for different models. If you needed an expanded range, you could just swap in an extra 200 pages. To sell it internationally, just replace the insert – no translation needed. The book itself contains zero...

The sun is our planet’s source of natural illumination, and though we’ve mastered making artificial light sources, it remains extremely difficult to copy our nearby star. As if matching the intensity wasn’t enough, its spectral quality, collimation, and atmospheric scattering make it an special challenge. [Victor Poughon] has given it a go though , using a bank of LEDs and an interesting lens system. We’re used to lenses being something that can be bought off-the-shelf, but this design eschews that convenience by having the lenses manufactured and polished as an array, by JLC. The scattering is taken care of by a sheet of inkjet printer film, and the LEDs are mounted on a set of custom PCBs. The result is certainly a very bright light, and one whose collimation delivers a sun-like effect of coming from a great distance. It may not be as bright as the real thing, but it’s certainly something close. If you’d like something to compare it to, it’s not the first such light we’ve featured...

When we think of 8-bit computers, it’s natural to start with home computers. That’s where they live on in the collective memory. But a Z80, a 6502, or similar was more likely to be found unseen in a piece of industrial machinery, doing the job for which we’d today reach for a microcontroller. Sometimes these two worlds intersected, and thus we come to the EuroBEEB, a derivative of Acorn’s BBC Micro on a Eurocard. [Steve Crozier] has performed extensive research into this system and even produced a recreated PCB , providing a fascinating window into embedded computing in the early 1980s. The EuroBEEB was the work of Control Universal, a Cambridge-based company specialising in embedded computers. They produced systems based upon 6502 and 6809 processors, and joining their product line to the then-burgeoning BBC Micro ecosystem would have been an obvious step. The machine itself is a Eurocard with a simple 6502 system shipped with ACORN BBC Basic on ROM, and could be seen as a cut-down ...

Toaster oven reflow projects are such a done deal that there should be nothing new in one here in 2025. Take a toaster oven, an Arduino, and a thermocouple, and bake those boards! But [Paul J R] has found a new take on an old project , and better still, he’s found the most diminutive of toaster ovens from the Australian version of Kmart. We love the project for the tiny oven alone. The brains of the operation is an ESP32, in the form of either a TTGO TTDisplay board or an S3-Zero board on a custom carrier PCB, with a thermistor rather than a thermocouple for the temperature sensing, and a solid state relay to control mains power for the heater. All the resources are in a GitHub repository , but you may have to make do with a more conventionally-sized table top toaster oven if you’re not an Aussie. If you’re interested, but want a better controller board, we’ve got you covered . from Blog – Hackaday https://ift.tt/0ocewZq

Plastic has been a revolutionary material over the past century, with an uncountable number of uses and an incredibly low price to boot. Unfortunately, this low cost has led to its use in many places where other materials might be better suited, and when this huge amount of material breaks down in the environment it can be incredibly persistent and harmful. This has led to many attempts to recycle it, and one of the more promising efforts recently came out of a lab at Northwestern University . Plastics exist as polymers, long chains of monomers that have been joined together chemically. The holy grail of plastic recycling would be to convert the polymers back to monomers and then use them to re-make the plastics from scratch. This method uses a catalyst to break down polyethylene terephthalate (PET), one of the more common plastics. Once broken down, the PET is exposed to moist air which converts it into its constituent monomers which can then be used to make more PET for other uses....

Fake WiFi repeater with a cheap real one behind it. (Credit: Big Clive, YouTube) Over the years we have seen a lot of fake electronics, ranging from fake power saving devices that you plug into an outlet, to fake car ECU optimizers that you stick into the OBD port. These are all similar in that they fake functionality while happily lighting up a LED or two to indicate that they’re doing ‘something’. Less expected here was that we’d be seeing fake WiFi repeaters, but recently [Big Clive] got his hands on one and undertook the arduous task of reverse-engineering it . The simple cardboard box which it comes in claims that it’s a 2.4 GHz unit that operates at 300 Mbps, which would be quite expected for the price. [Clive] obtained a real working WiFi repeater previously that did boast similar specifications and did indeed work. The dead giveaway that it is a fake are the clearly fake antennae, along with the fact that once you plug it in, no new WiFi network pops up or anything else. ...

We don’t often get our badminton rackets restrung, but if we did, [kuokuo702]’s PicoBETH project would be where we’d turn. This is a neat machine build for a very niche application, but it’s also a nicely elaborated project with motors, load cells, and even a sweet knobby-patterned faceplate that is certainly worth a look even if you’re not doing your own restringing. We’ll admit that everything we know about restringing rackets we learned by watching [kuokuo]’s demo video , but the basic procedure goes like this: you zigzag the string through the holes in the racket, controlling the tension at each stage along the way. A professional racket frame and clamp hold the tension constant while you fiddle the string through the next hole, but getting the tension just right in the first place is the job of [kuokuo]’s machine. It does this with a load cell, stepper motor, and ball screw, all under microcontroller control. Pull the string through, let the machine tension it, clamp it down, ...

By some estimates, the English language contains over a million unique words. This is perhaps overly generous, but even conservative estimates generally put the number at over a hundred thousand. Regardless of where the exact number falls between those two extremes, it’s certainly many more words than could fit in the 64 kB of memory allocated to the spell checking program on some of the first Unix machines. This article by [Abhinav Upadhyay] takes a deep dive on how the early Unix engineers accomplished the feat despite the extreme limitations of the computers they were working with . Perhaps the most obvious way to build a spell checker is by simply looking up each word in a dictionary. With modern hardware this wouldn’t be too hard, but disks in the ’70s were extremely slow and expensive. To move the dictionary into memory it was first whittled down to around 25,000 words by various methods, including using an algorithm to remove all affixes, and then using a Bloom filter to perfo...

Lithium technology has ushered in a new era of batteries with exceptionally high energy density for a reasonably low cost. This has made a lot possible that would have been unheard of even 20 years ago such as electric cars, or laptops that can run all day on a single charge. But like anything there are tradeoffs to using these batteries. They are much more complex to use than something like a lead acid battery, generally requiring a battery management system (BMS) to keep the cells in tip-top shape. Generally these are standalone systems but [CallMeC] integrated this one into the buswork for a battery pack instead . The BMS is generally intended to make sure that slight chemical imbalances in the battery cells don’t cause the pack to wear out prematurely. They do this by maintaining an electrical connection to each cell in the battery so they can charge them individually when needed, making sure that they are all balanced with each other. This BMS has all of these connections printe...

Those who indulge in trading card games know that building the best deck is the key to victory. What exactly that entails is a mystery to us muggles, but keeping track of your cards is a vital part of the process, one that this DIY card scanner (original German; English translation ) seeks to automate. At its heart, [Fraens]’ card scanner is all about paper handling, which is always an engineering task fraught with peril. Cards like those for Magic: The Gathering and other TCGs are meant to be handled by human hands, and automating the task of flipping through them presents some challenges. [Fraens] uses a pair of motorized 3D-printed rollers with O-rings to form a conveyor belt that can pull one card at a time off the bottom of a deck. An adjustable retaining roller made from the most adorable linear bearing we’ve ever seen ensures that only one card at a time is pulled from the hopper onto an imaging platen. An adjustable mount holds a smartphone to take a picture of the card, wh...

This week, Jonathan Bennett chats with Neal Gompa about Fedora 42 and KDE! What’s new, what’s coming, and why is flagship status such a big deal? Website: https://neal.gompa.dev/ GitHub Sponsors: https://github.com/sponsors/Conan-Kudo Neal’s business (Velocity Limitless): https://velocitylimitless.com/ Neal’s podcast (Sudo Show): https://tuxdigital.com/sudoshow 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 contact the guest and have them 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/0Pla1XB