Remembering Betty Webb: Bletchley Park & Pentagon Code Breaker

April 3, 2025 by 30 Comments
S/Sgt Betty Vine-Stevens, Washington DC, May 1945.
S/Sgt Betty Vine-Stevens, Washington DC, May 1945.

On 31 March of this year we had to bid farewell to Charlotte Elizabeth “Betty” Webb (née Vine-Stevens) at the age of 101. She was one of the cryptanalysts who worked at Bletchley Park during World War 2, as well as being one of the few women who worked at Bletchley Park in this role. At the time existing societal biases held that women were not interested in ‘intellectual work’, but as manpower was short due to wartime mobilization, more and more women found themselves working at places like Bletchley Park in a wide variety of roles, shattering these preconceived notions.

Betty Webb had originally signed up with the Auxiliary Territorial Service (ATS), with her reasoning per a 2012 interview being that she and a couple of like-minded students felt that they ought to be serving their country, ‘rather than just making sausage rolls’. After volunteering for the ATS, she found herself being interviewed at Bletchley Park in 1941. This interview resulted in a years-long career that saw her working on German and Japanese encrypted communications, all of which had to be kept secret from then 18-year old Betty’s parents.

Until secrecy was lifted, all her environment knew was that she was a ‘secretary’ at Bletchley Park. Instead, she was fighting on the frontlines of cryptanalysis, an act which got acknowledged by both the UK and French governments years later.

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A Very Trippy Look At Microsoft’s Beginnings

April 3, 2025 by 38 Comments

It’s not often you’ll see us singing the praises of Microsoft on these pages, but credit where credit is due, this first-person account of how the software giant got its foot in the proverbial door by Bill Gates himself is pretty slick.

Now it’s not the story that has us excited, mind you. It’s the website itself. As you scroll down the page, the text and images morph around in a very pleasing and retro-inspired way. Running your cursor over the text makes it flip through random ASCII characters, reminding us a bit of the “decryption” effect from Sneakers. Even the static images have dithering applied to them as if they’re being rendered on some ancient piece of hardware. We don’t know who’s doing Billy’s web design, but we’d love to have them come refresh our Retro Edition.

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Handheld 18650 Analyzer Scopes Out Salvaged Cells

April 3, 2025 by 10 Comments

You can salvage lithium 18650 cells from all sorts of modern gadgets, from disposable vapes to cordless power tools. The tricky part, other than physically liberating them from whatever they are installed in, is figuring out if they’re worth keeping or not. Just because an 18650 cell takes a charge doesn’t necessarily mean it’s any good — it could have vastly reduced capacity, or fail under heavy load.

If you’re going to take salvaging these cells seriously, you should really invest in a charger that is capable of running some capacity tests against the cell. Or if you’re a bit more adventurous, you can build this “Battery Health Monitor” designed by [DIY GUY Chris]. Although the fact that it can only accept a single cell at a time is certainly a limitation if you’ve got a lot of batteries to go though, the fact that it’s portable and only needs a USB-C connection for power means you can take it with you on your salvaging adventures.

The key to this project is a pair of chips from Texas Instruments. The BQ27441 is a “Fuel Gauge” IC, and is able to determine an 18650’s current capacity, which can be compared to the cell’s original design capacity to come up with an estimate of its overall health. The other chip, the BQ24075, keeps an eye on all the charging parameters to make sure the cell is being topped up safely and efficiently.

With these two purpose-built chips doing a lot of the heavy lifting, it only takes a relatively simple microcontroller to tie them together and provide user feedback. In this case [DIY GUY Chris] has gone with the ATmega328P, with a pair of addressable WS2812B LED bars to show the battery’s health and charge levels. As an added bonus, if you plug the device into your computer, it will output charging statistics over the serial port.

The whole project is released under the MIT license, and everything from the STL files for the 3D printed enclosure to the MCU’s Arduino-flavored firmware is provided. If you’re looking to build one yourself, you can either follow along with the step-by-step assembly instructions, or watch the build video below. Or really treat yourself and do both — you deserve it.

If your battery salvaging operation is too large for a single-cell tester, perhaps it’s time to upgrade to this 40-slot wall mounted unit.

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The Magic Touch: A 555 Touch Switch

April 2, 2025 by 14 Comments

There seems to be nothing a 555 can’t do. We’ve seen it before, but [electronzapdotcom] reminds us you can use a 555 and a few parts to make a reasonable touch switch in this video, embedded below.

The circuit uses some very large resistors so that noise from your body can overcome the logic level on the trigger and threshold inputs. You can easily adapt this idea if you need a simple touch switch. Though we imagine this circuit wouldn’t work well if you were in a quiet environment. We suspect 50 or 60 Hz hum is coupling through your finger and triggering the pins, but it could be a different effect.

How reliable is it? Beats us. The circuit is a bistable, so essentially your finger pumps a signal into a flip-flop. This is old trick, but could be useful. Of course, if you really need a touch switch, you have plenty of options. You can get little modules. Or, directly measure skin resistance.

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Monitor Your Smart Plugs On The Command Line

April 2, 2025 by 4 Comments

The plethora of smart home devices available today deliver all manner of opportunities, but it’s fair to say that interfacing with them is more often done in the browser or an app than in the terminal. WattWise from [Naveen Kulandaivelu] is a tool which changes all that, it’s a command-line interface (CLI) for power monitoring smart plugs.

Written in Python, the tool can talk either directly to TP-Link branded smart plugs, or via Home Assistant. It tracks the power consumption with a simple graph, but the exciting part lies in how it can be used to throttle the CPU of a computer in order to use power at the points in the day when it is cheapest. You can find the code in a GitHub repository.

We like the idea of using smart plugs as instruments, even if they may not be the most accurate of measurement tools. It takes them even further beyond the simple functionality and walled-garden interfaces provided by their manufacturers, which in our view can only be a good thing.

Meanwhile, for further reading we’ve looked at smart plugs in detail in the past.

Mockup of a printed copy of the Little OS Book

One Book To Boot Them All

April 2, 2025 by 19 Comments

Somewhere in the universe, there’s a place that lists every x86 operating system from scratch. Not just some bootloaders, or just a kernel stub, but documentation to build a fully functional, interrupt-handling, multitasking-capable OS. [Erik Helin and Adam Renberg] did just that by documenting every step in The Little Book About OS Development.

This is not your typical dry academic textbook. It’s a hands-on, step-by-step guide aimed at hackers, tinkerers, and developers who want to demystify kernel programming. The book walks you through setting up your environment, bootstrapping your OS, handling interrupts, implementing virtual memory, and even tackling system calls and multitasking. It provides just enough detail to get you started but leaves room for exploration – because, let’s be honest, half the fun is in figuring things out yourself.

Completeness and structure are two things that make this book stand out. Other OS dev guides may give you snippets and leave you to assemble the puzzle yourself. This book documents the entire process, including common pitfalls. If you’ve ever been lost in the weeds of segmentation, paging, or serial I/O, this is the map you need. You can read it online or fetch it as a single 75-page long PDF.

Mockup photo source: Matthieu Dixte

Programmer’s Macro Pad Bangs Out Whole Functions

April 2, 2025 by 24 Comments

Macro pads are handy for opening up your favorite programs or executing commonly used keyboard shortcuts. But why stop there?

That’s what [Jeroen Brinkman] must have been thinking while creating the Programmer’s Macro Pad. Based on the Arduino Pro Micro, this hand-wired pad is unique in that a single press of any of its 16 keys can virtually “type” out multiple lines of text. In this case, it’s a capability that’s being used to prevent the user from having to manually enter in commonly used functions, declarations, and conditional statements.

For example, in the current firmware, pressing the “func” key will type out a boilerplate C function:

int () { //
;
return 0;
}; // f

It will also enter in the appropriate commands to put the cursor where it needs to be so you can actually enter in the function name. The other keys such as “array” and “if” work the same way, saving the user from having to enter (and potentially, even remember) the correct syntax.

The firmware is kept as simple as possible, meaning that the functionality of each key is currently hardcoded. Some kind of tool that would let you add or change macros without having to manually edit the source code and flash it back to the Arduino would be nice…but hey, it is a Programmers Macro Pad, after all.

Looking to speed up your own day-to-day computer usage? We’ve covered a lot of macro pads over the years, we’re confident at least a few of them should catch your eye.