Lithium-Ion Batteries: WHY They Demand Respect

November 4, 2025 by 55 Comments

This summer, we saw the WHY (What Hackers Yearn) event happen in Netherlands, of course, with a badge to match. Many badges these days embrace the QWERTY computer aesthetic, which I’m personally genuinely happy about. This one used 18650 batteries for power, in a dual parallel cell configuration… Oh snap, that’s my favourite LiIon cell in my favourite configuration, too! Surely, nothing bad could happen?

Whoops. That one almost caught me by surprise, I have to shamefully admit. I just genuinely love 18650 cells, in all glory they bring to hardware hacking, and my excitement must’ve blindsided me. They’re the closest possible entity to a “LiIon battery module”, surprisingly easy to find in most corners of this planet, cheap to acquire in large quantities, easy to interface to your projects, and packing a huge amount of power. It’s a perfect cell for many applications I and many other hackers hold dear.

Sadly, the 18650 cells were a bad choice for the WHY badge, for multiple reasons at once. If you’re considering building a 18650-based project, or even a product, let me show you what exactly made these cells a bad fit, and how you might be able to work around those limitations on your own journey. There’s plenty of technical factors, but I will tell you about the social factors, because these create the real dealbreaker here. Continue reading “Lithium-Ion Batteries: WHY They Demand Respect” →

Making Audible Sense Of A Radiation Hunt

November 4, 2025 by 17 Comments

The clicking of a Geiger counter is well enough known as a signifier of radioactive materials, due to it providing the menacing sound effect any time a film or TV show deals with radiation. What we’re hearing is the electronic detection of an ionization event in a Geiger-Muller tube due to alpha or beta radiation, which is great, but we’re not detecting gamma radiation.

For that a scintillation detector is required, but these are so sensitive to background radiation as to make the clicking effect relatively useless as an indicator to human ears. Could a microcontroller analyse the click rate and produce an audible indication? This is the basis of [maurycyz]’s project, adding a small processor board to a Ludlum radiation meter.

When everything sounds like a lot of clicks, an easy fix might be to use a divider to halve the number and make concentrations of clicks sound more obvious. It’s a strategy with merit, but one that results in weaker finds being subsumed. Instead the approach here is to take a long-term background reading, and compare the instantaneous time between clicks with it. Ths any immediate click densities can be highlighted, and those which match the background can be ignored. SO in goes an AVR128 for which the code can be found at the above link.

The result is intended for rock prospecting, a situation where it’s much more desirable to listen to the clicks than look at the meter as you scan the lumps of dirt. It’s not the first project in this line we’ve brought you, another one looked at the scintillation probe itself.

Adding ISA Ports To Modern Motherboards

November 3, 2025 by 23 Comments

Modern motherboards don’t come with ISA slots, and almost everybody is fine with that. If you really want one, though, there are ways to get one. [TheRasteri] explains how in a forum post on the topic.

Believe it or not, some post-2010 PC hardware can still do ISA, it’s just that the slots aren’t broken out or populated on consumer hardware. However, if you know where to look, you can hack in an ISA hookup to get your old hardware going. [TheRasteri] achieves this on motherboards that have the LPC bus accessible, with the use of a custom PCB featuring the Fintek F85226 LPC-to-ISA bridge. This allows installing old ISA cards into a much more modern PC, with [TheRasteri] noting that DMA is fully functional with this setup—important for some applications. Testing thus far has involved a Socket 755 motherboard and a Socket 1155 motherboard, and [TheRasteri] believes this technique could work on newer hardware too as long as legacy BIOS or CSM is available.

It’s edge case stuff, as few of us are trying to run Hercules graphics cards on Windows 11 machines or anything like that. But if you’re a legacy hardware nut, and you want to see what can be done, you might like to check out [TheRasteri’s] work over on Github. Video after the break.

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Reproduced And Recovered: The First Chinese Keyboard-based MingKwai Typewriter

November 3, 2025 by 4 Comments

We all know what a typewriter looks like, and how this has been translated directly into the modern day computer keyboard, or at least many of us think we do. Many cultures do not use a writing system like the Roman or Cyrillic-style alphabets, with the Chinese writing system probably posing the biggest challenge. During the rise of mechanical typewriters, Chinese versions looked massive, clumsy and slow as they had to manage so many different symbols. All of them, except for one prototype of the MingKwai, which a group of Chinese enthusiasts have recently built themselves using the patent drawings.

Interestingly, when they started their build, it was thought that every single prototype of the MingKwai had been lost to time. That was before a genuine prototype was found in a basement in New York and acquired by Stanford University Libraries, creating the unique experience of being able to compare both a genuine prototype and a functional recreation.

Considered to be the first Chinese typewriter with a keyboard, the MingKwai (明快打字機, for ‘clear and fast’) was developed by [Lin Yutang] in the 1940s. Rather than the simple mechanism of Western typewriters where one key is linked directly to one hammer, the MingKwai instead uses the keys as a retrieval, or indexing mechanism.

Different rows select a different radical from one of the multiple rolls inside the machine, with a preview of multiple potential characters that these can combine to. After looking at these previews in the ‘magic eye’ glass, you select the number of the target symbol. In the video by the Chinese team this can be seen in action.

Although [Lin]’s MingKwai typewriter did not reach commercialization, it offered the first glimpse of a viable Chinese input method prior to computer technology. These days the popular pinyin uses the romanized writing form, which makes it somewhat similar to the standard Japanese input method using its phonetic kana system of characters. Without such options and within the confined system of 1940s electromechanical systems, however, the MingKwai is both an absolute marvel of ingenuity, and absolutely mindboggling even by 2020s standards.

Continue reading “Reproduced And Recovered: The First Chinese Keyboard-based MingKwai Typewriter” →

Regular Old Diodes Can Be More Photosensitive Than You Think

November 3, 2025 by 26 Comments

[Dhananjay Gadre] happened across a useful little trick the other day. Take any old 1N4148 or 1N914 glass-package signal diode and wire it up right, and you’ve got yourself a nifty little IR detector.

It’s that simple.

The trick is to treat the diode just like you would a proper IR photodiode. The part should be reverse biased with a resistor inline, and the signal taken from the anode side. Point an IR remote at your little diode and you’ll readily see the modulated signal pop up on a scope, clear as day.

The phenomenon is discussed at length over on Stack Exchange. Indeed, it’s a simple fact that most semiconductor devices are subject to some sort of photoelectric effect or another. It’s just that we stick the majority of them in opaque black packages so it never comes up in practice. In reality, things like photodiodes and phototransistors aren’t especially different from the regular parts—they’re just put in transparent packages and engineered and calibrated to give predictable responses when used in such a way.

Is this the way you’d go if your project needed an IR detector? Probably not—you’d be better served buying the specific parts you need from the outset. But, if you find yourself in a pinch, and you really need to detect some IR signals and all you’ve got on hand is glass-package signal diodes? Yeah, you can probably get it to work.

While this trick is well known to many oldheads, it’s often a lightbulb moment for many up-and-coming engineers and makers to realize this. Glass-packaged diodes aren’t the only light-sensitive parts out there, either. As we’ve explored previously, certain revisions of Raspberry Pi would reboot if exposed to a camera flash, while you can even use regular old LEDs as sensors if you’re so inclined. If you’ve got your own secret knowledge about how to repurpose regular components in weird ways, don’t hesitate to notify the tipsline!

Print in place board holder

Print-and-Clamp: Rubber Band PCB Stand Slides Into Duty

November 3, 2025 by 12 Comments

When it comes to soldering on a PCB it almost always helps to have some way to hold the board off your workbench, allowing leads to pass though with out making it unstable and keeping it level while working with tiny components. This project sent in by [Mel] was born out of necessity he was going to be teaching a soldering class and needed a way to keep boards in place, and so designed this Print-in-place PCB holder.

While there are certainly a long list of products designed to serve this function [Mel] took advantage of some idle 3D printers to turn out PCB stands that require no assembly, just the addition of a rubber band and they are ready for use. Part of the challenge of print in place 3D prints is dialing in the tolerances of your design and printer, and for this [Mel] printed some smaller slider mechanisms that were quick to print and iterate with until he was happy and could start turning out the larger design using those values.

The full PCB holder includes 3 independent sliders allowing for boards of all shapes and sizes to be held. To tension the board mounts there is a slow lower down on the uprights to allow for a rubber band to be added pulling all three towards the center. Finally [Mel] included small trays between the 3 sliders to give you a convenient place to components are you assemble your board. The 3D print falls are all available for download and [Mel] also included the small slider as a 3D print for you to check your printer tollerances before you run off the final design. Thanks [Mel] for sending in your soldering tool design, it’s a great addition to some of our other soldering assistant devices we’ve featured.

Dual-Arm Mobile Bot Built On IKEA Cart Costs Hundreds, Not Thousands

November 3, 2025 by 6 Comments

There are many incredible open-source robotic arm projects out there, but there’s a dearth of affordable, stable, and mobile robotic platforms with arms. That’s where XLeRobot comes in. It builds on the fantastic LeRobot framework to make a unit that can be trained for autonomous tasks via machine learning, as well as operated remotely.

XLeRobot, designed by [Vector Wang], has a pretty clever design that makes optimal use of easy to obtain parts. In addition to the mostly 3D-printed hardware, it uses an IKEA cart with stacked bin-like shelves as its main frame.

The top bin holds dual arms and a central stalk with a “head”. There’s still room left in that top bin, a handy feature that gives the robot a place to stow or carry objects.

The bottom of the cart gets the three-wheeled motion unit. Three omnidirectional wheels provide a stable base while also allowing the robot to propel itself in any direction and turn on a dime. The motion unit bolts to the bottom, but because the IKEA cart’s shelf bottoms are a metal mesh, no drilling is required.

It’s all very tidy, and results in a mobile robotics platform that is cheap enough for most hobbyists to afford, while being big enough to navigate indoor environments and do useful tasks.

Continue reading “Dual-Arm Mobile Bot Built On IKEA Cart Costs Hundreds, Not Thousands” →