Esp-hal, A Stable-API ESP32 HAL Gift For Your Rust Code

February 27, 2025 by Arya Voronova 14 Comments

Looking to write Rust on the ESP32? You’re in luck, a new challenger has entered the scene, looking to help you write code that lasts – [Scott Mabin] and the team from Espressif have brought us the esp-hal 1.0.0-beta. From a personal project to an Espressif-sponsored one to an effort under Espressif’s wing, [Scott] tells us about the arduous journey of bringing first-class Rust support to ESP32 chips, Xtensa and RISC-V alike.

In particular, esp-hal, with the hal part standing for Hardware Abstraction Layer, focuses on providing you with a stable API to access hardware, making sure your code can remain stable for years to come. For now, you get drivers for GPIO, UART, SPI and I2C, as well as a number of auxiliary features like time and SoC reset, more than enough for a large amount of projects we hackers build with a generic MCU in mind.

Next stop? WiFi and BLE support, of course, an ESP32 just doesn’t feel the same without these two. Rust is a fun and seriously promising language, and it’s a joy to use! So, if you have a wireless-less project in mind and you’re looking for a HAL, try out the esp-hal, it might just be exactly what you need.

If you’re looking for examples, here’s an STM32 touchpad project with Rust firmware, a PIC32 Rust blinky demo, and we’ve even featured larger projects like this ESP32 open-source (reverse-engineered) WiFi MAC stack being written in Rust. In case you missed it, we’ve introduced Rust to you a couple of times, even as far as 2015!

A Web-Based Graphics Editor For Tiny Screens

February 22, 2025 by Tom Nardi 18 Comments

These days, adding a little LCD or OLED to your project is so cheap and easy that you can do it on a whim. Even if your original idea didn’t call for a display, if you’ve got I2C and a couple bucks burning a hole in your pocket, why not add one? Surely you’ll figure out what to show on it as the project develops.

But that’s where it can get a little tricky — in terms of hardware, adding a screen just takes running a few extra wires, but the software side is another story. Not only do you have to contend with the different display libraries, but just creating the image assets to display on the screen can be a hassle if it’s not something you do regularly. Enter Lopaka, a graphics and user interface editor for electronic projects created by [Mikhail Ilin].

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UNIX Archaeology Turns Up 1972 “V2 Beta”

February 20, 2025 by Jenny List 20 Comments

In 1997 a set of DEC tapes were provided by Dennis Ritchie, as historical artifacts for those interested in the gestation of the UNIX operating system. The resulting archive files have recently been analysed by [Yfeng Gao], who has succeeded in recovering a working UNIX version from 1972. What makes it particularly interesting is that this is not a released version, instead it’s a work in progress sitting somewhere between versions 1 and 2. He’s therefore taken the liberty of naming it “V2 Beta”.

If you happen to have a PDP-11/20 you should be able to run this operating system for yourself, and for those of us without he’s provided information on which emulator will work. The interesting information for us comes in the README accompanying the tapes themselves, and in those accompanying the analysis. Aside from file fragments left over from previous users of the same tape, we learn about the state of UNIX time in 1972. This dates from the period when increments were in sixtieths of a second due to the ease of using the mains power frequency in a PDP, so with a 32-bit counter they were facing imminent roll-over. The 1970-01-01 epoch and one second increments would be adopted later in the year, but meanwhile this is an unusual curio.

If you manage to run this OS, and especially if you find anything further in the files, we’d love to hear. Meanwhile, this is not the oldest UNIX out there.

Featured image: “PDP-11/20 Rocker Switches” by Don DeBold

Belfry OpenSCAD Library (BOSL2) Brings Useful Parts And Tools Aplenty

February 18, 2025 by Donald Papp 16 Comments

OpenSCAD has a lot of fans around these parts — if you’re unaware, it’s essentially a code-based way of designing 3D models. Instead of drawing them up in a CAD program, one writes a script that defines the required geometry. All that is made a little easier with the Belfry OpenSCAD Library (BOSL2).

Designing a part like this is a cinch with BOSL2.

BOSL2 has an extensive library of base shapes, advanced functions for manipulating models, and some really nifty tools for creating attachment points on parts and aligning components with one another. If that sounds handy for designing useful objects, you’re in for even more of a treat when you see their functions for gears, hinges, screws, and more.

There’s even one that covers bottle necks and caps. (Those are all standardized by the way, so it’s never been easier to interface to existing bottles or caps in a project.)

OpenSCAD really is very versatile software. It powers useful tools like this screw, washer, and nut generator as well as having more unusual applications like a procedural terrain generator. It’s free, so if you’ve never looked into it, check it out!

Tiny Typing Tutor Tuts At Your Incorrect Shift Usage

February 13, 2025 by Lewin Day 16 Comments

There are a wide range of typing tutors out there that will educate you in the glorious skill of touch-typing. Many just focus on the basics, ranking you on accuracy and speed. However, there’s a nifty little online tutor that can help you with one skill specifically—it’s aim is to teach you to use the Shift keys “properly.”

The tutor is the work of [KaarelP2rtel]. The unnamed tool is intended to guide you into instinctively using both the left and right Shift keys as you type. Many typers default to using one or the other. This can lead to fumbles and slowdown when one hand is trying to hit both the Shift key and a letter.

[KaarelP2rtel]’s belief is that the “correct” method is to press the Shift key with the opposite hand to the one typing the letter, and this typing tutor enforces that practice. You must type repeated capitalized words one after the other, and you’ll only progress quickly if you’re hitting the opposite Shift key each time. Unconventional keyboardists fear not—you can convert the tool to work with Dvorak or Colemak layouts if necessary.

Is this a crucial tool for the fast typist? The jury’s out on that one. It’s entirely possible to hit in excess of 120 wpm without this technique for most normal passages of text, using dynamic finger reassignments when hitting Shift with the same hand. Still, the diligent may find it a useful upgrade to their existing typing abilities.

Source code is on GitHub for the curious. Notably, it’s a very small website that weighs in at just a few kilobytes; it would be a rather fitting part of the Small Web, which we’ve explored before!

Make A Secret File Stash In The Slack Space

February 10, 2025 by Donald Papp 15 Comments

Disk space is allocated in clusters of a certain size. When a file is written to disk and the file size is smaller than the cluster(s) allocated for it, there is an unused portion of varying size between the end of the file’s data and the end of the allocated clusters. This unused space is the slack space, it’s perfectly normal, and [Zachary Parish] had an idea to write a tool to hide data in it.

The demo uses a usb drive, using the slack space from decoy files to read and write data.

[Zachary]’s tool is in Python and can map available slack space and perform read and write operations on it, treating the disparate locations as a single unified whole in which to store arbitrary files. A little tar and gzip even helps makes things more efficient in the process.

There’s a whole demo implemented on Linux using a usb drive with some decoy files to maximize the slack space, and you can watch it in action in the video embedded below. It’s certainly more practical than hiding data in a podcast!

Note that this is just a demo of the concept. The approach does have potential for handling secret data, but [Zachary] points out that there are — from a serious data forensics point of view– a number of shortcomings in its current form. For example, the way the tool currently structures and handles data makes it quite obvious that something is going on in the slack space.

[Zachary] created this a few years ago and has some ideas about how to address those shortcomings and evolve the tool, so if you have ideas of your own or just want to try it out, the slack_hider GitHub repository is where you want to go.

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Screenshot of Linux in a PDF in a browser

Nice PDF, But Can It Run Linux? Yikes!

February 10, 2025 by Heidi Ulrich 21 Comments

The days that PDFs were the granny-proof Swiss Army knives of document sharing are definitely over, according to [vk6]. He has managed to pull off the ultimate mind-bender: running Linux inside a PDF file. Yep, you read that right. A full Linux distro chugging along in a virtual machine all encapsulated within a document. Just when you thought running DOOM was the epitome of it. You can even try it out in your own browser, right here. Mind-boggling, or downright Pandora’s box?

Let’s unpack how this black magic works. The humble PDF file format supports JavaScript – with a limited standard library, mind you. By leveraging this, [vk6] managed to compile a RISC-V emulator (TinyEMU) into JavaScript using an old version of Emscripten targeting asm.js instead of WebAssembly. The emulator, embedded within the PDF, interfaces with virtual input through a keyboard and text box.

The graphical output is ingeniously rendered as ASCII characters – each line displayed in a separate text field. It’s a wild solution but works astonishingly well for something so unconventional.

Security-wise, this definitely raises eyebrows. PDFs have long been vectors for malware, but this pushes things further: PDFs with computational power. We know not to trust Word documents, whether they just capable of running Doom, or trash your entire system in a blink. This PDF anomaly unfolds a complete, powerful operating system in front of your very eyes. Should we think lightly, and hope it’ll lead to smarter, more interactive PDFs – or will it bring us innocent looking files weaponized for chaos?

Curious minds, go take a look for yourself. The project’s code is available on GitHub.

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