Lumafield battery quality report cover page

Lumafield Peers Into The 18650 Battery

January 31, 2026 by John Elliot V 21 Comments

[Alex Hao] and [Andreas Bastian] of Lumafield recently visited with [Adam Savage] to document their findings after performing X-ray computed tomography scans on over 1,000 18650 lithium-ion batteries.

The short version — don’t buy cheap cells! The cheaper brands were found to have higher levels of manufacturing defects which can lead them to being unsafe. All the nitty-gritty details are available in the report, which can be downloaded for free from Lumafield, as well as the Tested video they did with [Adam] below.

Actually we’ve been talking here at Hackaday over at our virtual water-cooler (okay, okay, our Discord server) about how to store lithium-ion batteries and we learned about this cool bit of kit: the BAT-SAFE. Maybe check that out if you’re stickler for safety like us! (Thanks Maya Posch!)

We have of course heard from [Adam Savage] before, check out [Adam Savage] Giving A Speech About The Maker Movement and [Adam Savage]’s First Order Of Retrievability Tool Boxes.

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Surviving The RAM Price Squeeze With Linux In-Kernel Memory Compression

January 31, 2026 by John Elliot V 41 Comments

You’ve probably heard — we’re currently experiencing very high RAM prices due mostly to increased demand from AI data centers.

If you’ve been priced out of new RAM you are going to want to get as much value out of the RAM you already have as possible, and that’s where today’s hack comes in: if you’re on a Debian system read about ZRam for how to install and configure zram-tools to enable and manage the Linux kernel facilities that enable compressed RAM by integrating with the swap-enabled virtual memory system. We’ve seen it done with the Raspberry Pi, and the concept is the same.

Ubuntu users should check out systemd-zram-generator instead, and be aware that zram might already be installed and configured by default on your Ubuntu Desktop system.

If you’re interested in the history of in-kernel memory compression LWN.net has an old article covering the technology as it was gestating back in 2013: In-kernel Memory Compression. For those trying to get a grip on what has happened with RAM prices in recent history, a good place to track memory prices is memory.net and if you swing by you can see that a lot of RAM has gone up as much as four times in the last three or four months.

If you have any tips or hacks for memory compression on other platforms we would love to hear from you in the comments section!

A man cutting wood with a circular bench saw

Ultimate Picture Frame Combines Walnut And 3D Printing

January 28, 2026 by John Elliot V 7 Comments

[Make Something] boasts he has made probably the fanciest picture frame you’ll ever see. He started with an original sign purchased on eBay and then made it to be bigger, brighter, and better. The frame is of solid walnut with back-lighting for the imagery all chasing that classic mid-century modern style. The backlit photo was taken the “hard way”, with an actual film camera and a road-trip to the picturesque site at Yellowstone. [Make Something] then developed the film himself in his home studio.

For the chimney [Make Something] used a new trick he learned in Autodesk Fusion: you take a photo of an object, convert to black and white, and then use the light/dark values to emboss or deboss a surface. To do this he took photos of the brick wall outside his shop and used that as the basis of the textured chimney he made with his 3D printer.

If you’re interested in other projects made from solid walnut, check out 3D Printed Spirograph Makes Art Out Of Walnut and Walnut Case Sets This Custom Arduino-Powered RPN Calculator Apart From The Crowd.

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[nanofix] and his assortment of tweezers

Reviewing Tweezers For Microsoldering And SMD Work

January 24, 2026 by John Elliot V 9 Comments

Attributed to Picasso was the notion that when art critics get together they talk about content, style, trend, and meaning; but that when painters get together they talk about where to get the best turpentine. We can extend that sentiment into the digital age by saying that when philosophers get together they talk about ideas, theory, and meaning; but when hackers get together they talk about where to get the best tweezers.

In this video [nanofix] runs us through his collection of tweezers talking about what he likes and doesn’t like for each. If you’re just getting into microsoldering this video will have some tips about where you should start, and if you’ve been soldering tiny stuff for a while you might find some ideas for a helpful new bit of kit, or two.

If you’re interested in tweezers and novel applications you might want to check out “smart” tweezers, which can read capacitance and resistance values on the fly. Or read about a suction based SMD tool, which can securely hold SMD components with less risk of them flying across the bench and disappearing forever into the carpet on the floor.

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Nic Barker Explains ASCII, Unicode, And UTF-8

January 22, 2026 by John Elliot V 15 Comments

Over on YouTube [Nic Barker] gives us: UTF-8, Explained Simply.

If you’re gonna be a hacker eventually you’re gonna have to write software to process and generate text data. And when you deal with text data, in this day and age, there are really only two main things you need to know: 7-bit ASCII and UTF-8. In this video [Nic] explains 7-bit ASCII and Unicode, and then explains UTF-8 and how it relates to Unicode and ASCII. [Nic] goes into detail about some of the clever features of Unicode and UTF-8 such as self-synchronization, single-byte ASCII, multi-byte codepoints, leading bytes, continuation bytes, and grapheme clusters.

[Nic] mentions about UTF-16, but UTF-16 turned out to be a really bad idea. UTF-16 combines all of the disadvantages of UTF-8 with all of the disadvantages of UTF-32. In UTF-16 there are things known as “surrogate pairs”, which means a single Unicode codepoint might require two UTF-16 “characters” to describe it. Also the Byte Order Marks (BOM) introduced with UTF-16 proved to be problematic. Particularly if you cat files together you can end up with stray BOM indicators randomly embedded in your new file. They say that null was a billion dollar mistake, well, UTF-16 was the other billion dollar mistake.

tl;dr: don’t use UTF-16, but do use 7-bit ASCII and UTF-8.

Oh, and as we’re here, and talking about Unicode, did you know that you can support The Unicode Consortium with Unicode Adopt-a-Character? You send money to sponsor a character and they put your name up in lights! Win, win! (We noticed while doing the research for this post that Jeroen Frijters of IKVM fame has sponsored #, a nod to C#.)

If you’re interested in learning more about Unicode check out Understanding And Using Unicode and Building Up Unicode Characters One Bit At A Time.

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A hand holding the Zoyi ZT-QB9 Smart Clamp meter

Review And Demo Of The Zoyi ZT-QB9 Smart Clamp Meter

January 18, 2026 by John Elliot V 14 Comments

Over on YouTube [Kiss Analog] reviews the New Zoyi ZT-QB9 Smart Clamp meter.

If you’re putting together an electronics lab from scratch you absolutely must get a multimeter to start. A typical multimeter will be able to do current measurements but it will require you to break the circuit you’re measuring and interface it to your meter using its mechanical probes.

A good choice for your second, or third, multimeter is a clamp-based one. Many of the clamp meters have the clamp probe available for current measurements while still allowing you to use the standard 4mm banana jack probes for other measurements, particularly voltage and resistance.

If you’re curious to know more about how clamp meters work the answer is that they rely on some physics called the Hall Effect, as explained by the good people at Fluke.

In the video the following clamp meters are seen: Zoyi ZT-QB9, PROVA 11, and Hioki CM4375. If you’re in the market for a clamp meter you might also like to consider the EEVblog BM036 or a clamp meter from Fluke.

We have of course posted about clamp meters before. Check out Frnisi DMC-100: A Clamp Meter Worth Cracking Open or ESP32 Powers DIY Smart Energy Meter if you’d like to know more. Have your own trusty clamp meter? Don’t need no stinkin’ clamp meter? Let us know in the comments!

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[Dr Ali Shirsavar] drawing schematics and equations on the whiteboard

Calculating The Capacitance And ESR Specifications For The Output Capacitor In Your Switching-Mode Power Supply

January 18, 2026 by John Elliot V 13 Comments

[Dr Ali Shirsavar] from Biricha Digital runs us through How to Select the Perfect Output Capacitor for Your Power Supply. Your switching-mode power supply (SMPS) will require an output capacitor both to iron out voltage swings due to loading and to attenuate ripple caused by switching. In this video we learn how to calculate the required capacitance, and when necessary the ESR, for your output capacitor.

To begin [Dr Ali] shows us that in order to calculate the minimum capacitance to mitigate voltage swings we need values for Δi, Δv, and T_s. Using these we can calculate the minimum output capacitance. We then need to calculate another minimum capacitance for our circuit given that we need to attenuate ripple. To calculate this second minimum we need to change our approach depending on the type of capacitor we are using, such as ceramic, or electrolytic, or something else.

When our circuit calls for an electrolytic capacitor the equivalent series resistance (ESR) becomes relevant and we need to take it into account. The ESR is so predominant that in our calculations for the minimum capacitance to mitigate ripple we can ignore the capacitance and use the ESR only as it is the feature which dominates. [Dr Ali] goes into detail for both examples using ceramic capacitors and electrolytic capacitors. Armed with the minimum capacitance (in Farads) and maximum ESR (in Ohms) you can then go shopping to find a capacitor which meets the requirements.

If you’re interested in capacitors and capacitance you might enjoy reading about Measuring Capacitance Against Voltage and Getting A Handle On ESR With A Couple Of DIY Meters.