Off To The Races With ESP32 And EInk

September 15, 2025 by 14 Comments

Off to the races? Formula One races, that is. This project by [mazur8888] uses an ESP32 to keep track of the sport, and display a “live” dashboard on a 2.9″ tri-color LCD.

“Live” is in scare quotes because updates are fetched only every 30 minutes; letting the ESP32 sleep the rest of the time gives the tiny desk gadget a smaller energy footprint. Usually that’s to increase battery life, but this version of the project does not appear to be battery-powered. Here the data being fetched is about overall team rankings, upcoming races, and during a race the current occupant of the pole-position.

There’s more than just the eInk display running on the ESP32; as with many projects these days, micro-controller is being pressed into service as a web server to host a full dashboard that gives extra information as well as settings and OTA updates. The screen and dev board sit inside a conventional 3D-printed case.

Normally when talking Formula One, we’re looking into the hacks race teams make. This hack might not do anything revolutionary to track the racers, but it does show a nice use for a small e-ink module that isn’t another weather display. The project is open source under a GPL3.0 license with code and STLs available on GitHub.

Thanks to [mazur8888]. If you’ve got something on the go with an e-ink display (or anything else) send your electrophoretic hacks in to our tips line; we’d love to hear from you.

Flashlight Repair Brings Entire Workshop To Bear

September 15, 2025 by 16 Comments

The modern hacker and maker has an incredible array of tools at their disposal — even a modestly appointed workbench these days would have seemed like science-fiction a couple decades ago. Desktop 3D printers, laser cutters, CNC mills, lathes, the list goes on and on. But what good is all that fancy gear if you don’t put it to work once and awhile?

If we had to guess, we’d say dust never gets a chance to accumulate on any of the tools in [Ed Nisley]’s workshop. According to his blog, the prolific hacker is either building or repairing something on a nearly daily basis. All of his posts are worth reading, but the multifaceted rebuilding of a Anker LC-40 flashlight from a couple months back recently caught our eye.

Continue reading “Flashlight Repair Brings Entire Workshop To Bear” →

Going Native With Android’s Native Development Kit

September 15, 2025 by 8 Comments

Originally Android apps were only developed in Java, targeting the Dalvik Java Virtual Machine (JVM) and its associated environment. Compared to platforms like iOS with Objective-C, which is just C with Smalltalk uncomfortably crammed into it, an obvious problem here is that any JVM will significantly cripple performance, both due to a lack of direct hardware access and the garbage-collector that makes real-time applications such as games effectively impossible. There is also the issue that there is a lot more existing code written in languages like C and C++, with not a lot of enthusiasm among companies for porting existing codebases to Java, or the mostly Android-specific Kotlin.

The solution here was the Native Development Kit (NDK), which was introduced in 2009 and provides a sandboxed environment that native binaries can run in. The limitations here are mostly due to many standard APIs from a GNU/Linux or BSD environment not being present in Android/Linux, along with the use of the minimalistic Bionic C library and APIs that require a detour via the JVM rather than having it available via the NDK.

Despite these issues, using the NDK can still save a lot of time and allows for the sharing of mostly the same codebase between Android, desktop Linux, BSD and Windows.

Continue reading “Going Native With Android’s Native Development Kit” →

DIY USB-C PD Tools

USB-C PD Decoded: A DIY Meter And Logger For Power Insights

September 15, 2025 by 8 Comments

As USB-C PD becomes more and more common, it’s useful to have a tool that lets you understand exactly what it’s doing—no longer is it limited to just 5 V. This DIY USB-C PD tool, sent in by [ludwin], unlocks the ability to monitor voltage and current, either on a small screen built into the device or using Wi-Fi.

This design comes in two flavors: with and without screen. The OLED version is based on an STM32, and the small screen shows you the voltage, current, and wattage flowing through the device. The Wi-Fi PD logger version uses an ESP-01s to host a small website that shows you those same values, but with the additional feature of being able to log that data over time and export a CSV file with all the collected data, which can be useful when characterizing the power draw of your project over time.

Both versions use the classic INA219 in conjunction with a 50 mΩ shunt resistor, allowing for readings in the 1 mA range. The enclosure is 3D-printed, and the files for it, as well as all the electronics and firmware, are available over on the GitHub page. Thanks [ludwin] for sending in this awesome little tool that can help show the performance of your USB-C PD project. Be sure to check out some of the other USB-C PD projects we’ve featured.

Continue reading “USB-C PD Decoded: A DIY Meter And Logger For Power Insights” →

Neural network shown on original mac screen, handwritten 2 on left and predictions on right

Original Mac Limitations Can’t Stop You From Running AI Models

September 15, 2025 by 14 Comments

Modern retrocomputing tricks often push old hardware and systems further than any of the back-in-the-day developers could have ever dreamed. How about a neural network on an original Mac? [KenDesigns] does just this with a classic handwritten digit identification network running with an entire custom SDK!

Getting such a piece of hardware running what is effectively multiple decades of machine learning is as hard as most could imagine. (The MNIST dataset used wasn’t even put together until the 90s.) Due to floating-point limitations on the original Mac, there are a variety of issues with attempting to run machine learning models. One of the several hoops to jump through required quantization of the model. This also allows the model to be squeezed into the limited RAM of the Mac.

Impressively, one of the most important features of [KenDesigns] setup is the custom SDK, allowing for the lack of macOS. This allows for incredibly nitty-gritty adjustments, but also requires an entire custom installation. Not all for nothing, though, as after some training manipulation, the model runs with some clear proficiency.

If you want to see it go, check out the video embedded below. Or if you just want to run it on your ancient Mac, you’ll find a disk image here. Emulators have even been tested to work for those without the original hardware. Newer hardware traditionally proves to be easier and more compact to use than these older toys; however, it doesn’t make it any less impressive to run a neural network on a calculator!

Continue reading “Original Mac Limitations Can’t Stop You From Running AI Models” →

UTF-8 Is Beautiful

September 14, 2025 by 30 Comments

It’s likely that many Hackaday readers will be aware of UTF-8, the mechanism for incorporating diverse alphabets and other characters such as 💩 emojis. It takes the long-established 7-bit ASCII character set and extends it into multiple bytes to represent many thousands of characters. How it does this may well be beyond that basic grasp, and [Vishnu] is here with a primer that’s both fascinating and easy to read.

UTF-8 extends ASCII from codes which fit in a single byte, to codes which can be up to four bytes long. The key lies in the first few bits of each byte, which specify how many bytes each character has, and then that it is a data byte. Since 7-bit ASCII codes always have a 0 in their most significant bit when mapped onto an 8-bit byte, compatibility with ASCII is ensured by the first 128 characters always beginning with a zero bit. It’s simple, elegant, and for any of who had to deal with character set hell in the days before it came along, magic.

We’ve talked surprisingly little about the internals of UTF-8 in the past, but it’s worthy of note that this is our second piece ever to use the poop emoji, after our coverage of the billionth GitHub repository.

Emoji bales: Tony Hisgett, CC BY 2.0.

E-Waste And Waste Oil Combine To Make Silver

September 14, 2025 by 12 Comments

As the saying goes, “if it can’t be grown, it has to be mined”– but what about all the metals that have already been wrested from the bosom of the Earth? Once used, they can be recycled– or as this paper charmingly puts it, become ore for “urban mining” techniques. The technique under discussion in the Chemical Engineering Journal is one that extracts metallic silver from e-waste using fatty acids and hydrogen peroxide.

This “graphical abstract” gives the rough idea.

Right now, recycling makes up about 17% of the global silver supply. As rich sources of ore dry up, and the world moves to more sustainable footing, that number can only go up. Recycling e-waste already happens, of course, but in messy, dangerous processes that are generally banned in the developed world. (Like open burning, of plastic, gross.)

This paper describes a “green” process that even the most fervant granola-munching NIMBY wouldn’t mind have in their neighborhood: hot fatty acids (AKA oil) are used as an organic solvent to dissolve metals from PCB and wire. The paper mentions sourcing the solvent from waste sunflower, safflower or canola oil. As you might imagine, most metals, silver included, are not terribly soluble in sunflower oil, but a little refining and the addition of 30% hydrogen peroxide changes that equation.

More than just Ag is picked up in this process, but the oils do select for silver over other metals. The paper presents a way to then selectively precipitate out the silver as silver oleate using ethanol and flourescent light. The oleate compound can then be easily washed and burnt to produce pure silver.

The authors of the paper take the time to demonstrate the process on a silver-plated keyboard connector, so there is proof of concept on real e-waste. Selecting for silver means leaving behind gold, however, so we’re not sure how the economics of this method will stack up.

Of course, when Hackaday talks about recycling e-waste, it’s usually more on the “reuse” part of “reduce, reuse, recycle”.  After all, one man’s e-waste is another man’s parts bin–or priceless historical artifact.

Thanks to [Brian] for the tip.Your tips can be easily recycled into Hackaday posts through an environmentally-friendly process via our tipsline.