ESP32 Rotary Display Makes Ideal Timer

October 27, 2026 by 4 Comments

We’re big fans of pushing hardware into situations it wasn’t designed for here at Hackaday, but sometimes you’ve got to appreciate a nicely designed gadget doing more or less exactly what it was intended for — especially when it’s courtesy of code that’s freely available for you to run and hack on however you like.

That’s precisely what [mircemk] has done with their “Universal Timer” project. The 2.1 inch CrowPanel “Rotary Display” at the heart of the build combines an ESP32-S3 with a 480×480 round touch screen display and a rotary encoder.

The all-in-one device — clearly meant to be reminiscent of the Nest thermostat and similar commercial offerings — is technically all you need, but in this case it’s been joined by a PCF8574 I2C I/O expander which in turn is used to drive a buzzer that provides a bit of audio feedback at the end of the countdown.

With the code [mircemk] has provided flashed onto the board, the rotary encoder ring built into the housing makes for an exceptionally intuitive input for setting the desired time. It’s a bit like a high-tech version of the classic kitchen timer, as shown in the video below, you simply twist the ring and the graphics on the display rotate accordingly. Unlike grandma’s clockwork timer of old however, this one can change color as it nears zero, which makes it easier to estimate how much time remains from across the room.

As the popularity of smartwatches has brought the cost of these circular displays down, we’ve started to see some very slick projects utilizing them. The various efforts to turn them into desktop “radar” displays for nearby flights are a particular favorite.

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The Oldest Windows App To Still Run On WIndows 11

October 26, 2026 by 10 Comments

In the open source world we are used to software being compiled from source for our particular distro, so while in a few cases an ancient release may still be in use, it’s just going to run on the latest distro version. But in the Windows world it’s rare for software to come with the source, so you’re left with a binary that will only run if your Windows version has the right APIs for it. Since the more recent versions of Windows dropped 16-bit support a while back, that means there must be a hard date set on the earliest Windows GUI application that can still run today. [Enlyth] decided to investigate.

Given that the earliest API supported in WIndows 11 is the 32-bit version, the hunt led straight to either the first Windows NT release and ancestor of Windows 11, or the Win32s extension for WIndows 3.1. Thus a 1993 Win32S version of Freecell runs happily, but that want’s the end of the trail. Somewhere in the pre-release builds of Windows NT 3.1 would be the requisite binary, but there’s a snag. Early Windows NT 3.1 APIs were incompatible with later ones. This led through a lot of crashing binaries to a November 1992 version of the CD player app, that ran because it called a DLL which happens to still be present. The need for another DLL to emulate a CD drive speaks volumes about the progress of the PC world, back then they were the last word in storage but who’s got one now?

That’s the earliest official binary to run, but the story’s not quite over. Windows 11 may not have a VDM to run 16-bit apps, but there’s a WINE VDM for that. Behold, Reversi from Windows 1.01 in November 1985, in Windows 11. Your ancient software may yet be saved.

In Praise Of A Legendary Power Transistor

October 26, 2026 by 10 Comments

There are some devices which achieve electronic immortality, it’s likely that you have used a few of them yourself. The 555 timer of course, or the 741 op-amp. [ElectronicsNotes] is here with another candidate that might not have been on your mind as you read the previous sentences, and it’s a transistor. The 2N3055 is an NPN power transistor, no, THE NPN power transistor, that has found its way into an astounding array of devices over the last six decades or more.

For such a ubiquitous device one might imagine that there’s not much new to know, but the video delivers on that front. Here as well as probably for you the 3055 has always been an epitaxial device whose quirks you likely know well, but originally it was something different. It used the hometaxial construction process on its launch in the early 1960s, but in the mid 1970s it was replaced by a version with the same capabilities but using the epitaxial process. The consequent higher Ft required modifications to circuits using the device to stop unwanted oscillation.

Where this is being written there are several 2N3055s, in the by now rather old office audio amplifier, in a bench power supply, and probably elsewhere too. It’s been superseded in many ways and its TO3 case now feels antiquated, but it will probably never entirely go away. Meanwhile if you’d like to read about another iconic 1960s device that never went away, we have you covered.

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Enable Resizable BAR On Unsupported Motherboards

October 26, 2026 by 12 Comments

Recently [Rod Burlamaqui] released the arc-rebar project on GitHub, enabling Intel GPUs to work significantly more efficiently if the system’s mainboard does not support resizable BAR. It does require a Debian or Ubuntu installation and of course a supported Intel GPU.

Although the resizable base address register (ReBAR) feature has been part of the PCIe specification for a while, its use was quite limited until Intel released its Arc series of graphic cards. These use this feature to map much more of the GPU’s video RAM (VRAM) into the PC’s address space than the standard 256 MB, assuming that the system is capable of decoding addresses above 4 GB, i.e. allow for 64-bit BARs.

For GPU manufacturers like AMD and Nvidia this wasn’t so much of an issue as their GPU designs developed in a world where ReBAR didn’t exist, while Intel’s new GPU generations were designed with ReBAR as a core feature, which naturally cripples performance if the mainboard does not have it enabled during PCIe bus enumeration.

This initramfs-based fix runs before the GPU driver loads and performs the requisite BAR configuration. In testing with an Intel Arc B580 GPU on a 2015-era Intel Xeon mainboard the difference between the default and the fixed bandwidth was a bump from a pitiful 15 GB/s to a respectable 392 GB/s, showing how this one fix can breathe new life into older systems.

Practice Japanese On An Inkplate 4Tempera EInk Device

October 26, 2026 by 2 Comments

Learning a new natural language can be a daunting proposition at the best of times, with repetition and immersion generally considered to be the best ways to build up not only vocabulary but also that innate sense for grammar and cultural details that sneak into every spoken language. Flash cards are one way to help with vocabulary and sentence building, such as [Peter Hraska]’s Enkiplate project that uses the Inkplate 4Tempera being an  interesting alternative to lugging a stack of cards with you.

Although the software also works in the browser, using the Inkplate or similar device means that you can keep it with you while it keeps track of your progress in learning the shown cards, with a starting pace of 12 cards per day to learn. It also shows you calendar items for that day and the weather using an online weather service.

Starting from basic kana, i.e. the two phonetic writing systems, the difficulty is slowly ramped up to cover kanji and then sentences. Due to the limitations of the 4Tempera’s ESP32-WROVER-E module’s local storage up to 16 flash cards can be stored at a time, with an application on a PC being necessary to obtain new cards.

Arduino Engine Runs Many Games

October 26, 2026 by 3 Comments

A few years ago, [Smashcat] ported a ZX Spectrum game called Manic Miner to the Arduino Uno. The Arduino has less memory than the original Spectrum did, so doing all this on an 8-bit microcontroller was no easy lift. Since then, parts of this original port have been adapted to produce a game engine, allowing [Smashcat] to port several other games to the Arduino Uno as well.

The engine is able to host a 2D map with the ability to scroll, at a resolution of 256×256, as well as up to nine sprites at the same time. The graphics are locked to 50 FPS, but only with a real Arduino Uno that has a crystal oscillator. Some replica boards do not have a timekeeping chip accurate enough to replicate the video signal, which is done without a framebuffer. That signal, as well as two PWM audio channels, are still generated directly as well, with only a few resistors needed to hook everything up to a monitor and a controller, including the option of using an NES controller.

With all of that running on the Arduino and it hooked up to the daughterboard that provides the controller interface as well as the resistors for the video signal to function and a driver for a speaker, the system now runs the original Manic Miner as well as three other games: Scramble, Space Invaders, and Pac Man.

The engine and the rest of the code are available on a GitHub page as well, and there’s even a WebAssembly version available to run various pieces of the software without the specific hardware. The original ZX Spectrum was an interesting machine too that still inspires builds like this, despite it being well over 40 years old now.

A two door pickup or ute in white with a black hood and blue accents. It's built from a chopped up BMW i3 REX EV.

BMW I3 Mod Brings Small Trucks To The EV Future

October 26, 2026 by 20 Comments

Trucks are handy, especially if you’ve got messy or dirty loads, but there aren’t a lot of options if you want a small electric pickup yet. [Michael Pick] decided to convert a BMW i3 into a utility vehicle.

After getting a new 12 V battery and cleaning the car up, [Pick] proceeded to disassemble the interior and remove the hatch from the car. Once he could look at the bones, he planned out the best places for the cut lines and removed the back half of the cabin.

The bed is built from plywood coated in penetrating epoxy and bedliner for weatherproofing, and special care was taken to seal the interface between the cabin and bed as the main electronics for the vehicle are housed in a compartment directly below. The taillight electronics were rehoused as the OEM lenses were too large to fit next to the tailgate opening.

The i3 has graced these pages before with a battery upgrade, and we’d be remiss not to remind you of the most famous EV to truck conversion, Truckla.

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