2026-04-17 13:00:13
Kei trucks are some of the smallest commercial vehicles out on the roads today. You can also get lots of cute kei RC cars if you’re into the toy side of things. [Victor] wanted to split the difference with Truck-Kun, and built a 1:3 scale kei truck to show off at a recent anime convention.
The build started with a classic hacker favorite—a bunch of old hoverboard motors. These brushless hub motors are pretty easy to drive and have plenty of torque right out of the box. A simple ladder frame was whipped up with a hoverboard wheel at each corner, with a body whipped up out of cardboard, paint, and a few 3D printed parts to hold everything together.
Steering was courtesy of a leadscrew and stepper motor from an old 3D printer. RP2040s were thrown in to talk to the motor controllers, while an ESP32-S3 was charged with communicating with an Xbox One controller to receive directional commands.
It was a neat build that stood tall over most any other kei RC car at Anime Los Angeles. Only, it ended in tears when the 100-pound machine accidentally drove at full throttle into a wall and smashed itself to pieces. Still, that’s just an excuse for [Victor] to build a better one for next year.
We love a good RC build around these parts, and we love kei trucks too.
2026-04-17 10:00:23
That boiling water is a contentious topic of discussion is clear, but what about hot air? When you take a 12 VDC, 280 Watt-rated air fryer and pit it against a bog-standard 240 VAC, 1400 Watt unit, which one would you want to use when you’re doing some camping or other exciting off-the-grid opportunities? Unlike with boiling water the physics aren’t as clear-cut here, so [Cahn] did some testing to figure out exactly what the efficiency numbers look like
Since air fryers rely on the transfer of thermal energy from the resistive heating element into the food, any thermal energy that’s not immediately transferred is effectively wasted. This, combined with the relatively low power rating and thus much higher time demand of the low-voltage air fryer is enough to set one’s expectations pretty low.
As scientific test samples chicken nuggets were used with the test, following a preheating period for the 12 VDC unit. Both units managed to hit a safe temperature inside the nuggets after 20 minutes, thus successfully staving off food poisoning, but the browning with the 240 VAC air fryer was much better.
As for the efficiency, the 12 VDC unit required 150 Wh for 20 minutes plus the 10 minutes of preheating, with 45 minutes total at 225 Watt to get proper browning. Meanwhile the 240 VAC unit burned through 250 Wh in 20 minutes, with no pre-heating, though only 230 Wh with no inverter losses included. As a final test, the 12 VDC unit was run at 400 Watt using 14.6 VDC input, which did indeed get it up to temperature much faster.
Thus both are equivalent, just with the caveat that the low-voltage unit will take considerably more time to get the same result. This mirrors the results with boiling water, where most options mostly vary in how much time they require to get water up to a boiling temperature.
2026-04-17 07:00:54
It’s fair to say that there are a lot of development board form factors for MCUs, with [Tech Dregs] over on yonder YouTube on the verge of adding another one to the pile, but not before he was having some serious thoughts on the implications of such a decision. Does this world really need another devboard with the ubiquitous 2.54 mm (0.1″) pitch pin headers, all so that it can perhaps be used in the same traditional 2.54 mm pitch breadboards?
The thought that [Tech Dregs] is playing with is to go for something more akin to the system-on-module (SoM) approach that’s reminiscent of the Raspberry Pi compute module form factor. This means using a 1 mm pitch for the headers and castellated edges in case you want use it as an SMT part, while breaking out many more pins of the onboard ESP32 module in far less space.
Obviously, the main advantage of this approach is that much like with compute modules you can leave most of the tedious cheap stuff on a carrier board, while the expensive to manufacture components are on a self-contained module. Meanwhile with the much finer pitch on the SoM contacts it’d straddle the divide between a 2.54 mm breadboard-capable devboard and a fully custom PCB, while making any mistakes on the carrier board much cheaper to redo.
The counterpoint here is of course that something like an ESP32 module is already a module with a finer pitch, but if you need more than just what it offers, or you want to use an STM32 or RP MCU across boards it could make a lot of sense.
Having 1 mm pitch breadboards would honestly also be rather nifty, natch. That said, what are your thoughts on this matter?
2026-04-17 04:00:11
Oscilloscopes and to lesser extent signals generators are useful tools for analyzing, testing and diagnosing circuits but we often take for granted how they work. Luckily, [FromConceptToCircuit] is here to show us how they’re made.
[FromConceptToCircuit] starts by selecting the hardware to use: an Artix-7-based FPGA and an FT2232 USB-serial converter. RS245 in synchronous FIFO mode is selected for its high bandwidth of about 400 Mbps. Then, they show how to wire it all up to your FPGA of choice. Now it’s time for the implementation; they go over how the FT2232 interfaces with the FPGA, going through the Verilog code step-by-step to show how the FPGA makes use of the link, building up from the basic transmission logic all the way up to a simple framed protocol with CRC8-based error detection. With all that, the FPGA can now send captured samples to the PC over USB.
Now it’s PC-side time! [FromConceptToCircuit] first explains the physical pipeline through which the samples reach the PC: FPGA captures, transmits over RS245, FT2232 interfaces that with USB and finally, the software talks with the FT2232 over USB to get the data back out. The software starts by configuring the FT2232 into RS245 mode, sets buffer sizes, the whole deal. With everything set up, [FromConceptToCircuit] explains how to use the FT2232 driver’s API for non-blocking communication.
As a bonus, [FromConceptToCircuit] adds a signal generator feature to the oscilloscope using an I2C DAC chip. They start by explaining what exactly the DAC does and follow up with how it’ll be integrated into the existing system. Then it’s time to explain how to implement the I2C protocol bit-for-bit. Finally combine everything together for one final demo that shows a sine wave on the DAC’s output.
2026-04-17 02:30:22
While it might seem quaint these days, we’ve met many makers and hackers who reach for a pen and a pad when learning something new or working their way through some technical problem. But even if you’re the type of person who thinks best when writing something out on paper, there’s still a good chance that you’ll eventually want to bring those notes and sketches into the digital realm. That’s where things can get a little tricky.
[Spencer Adams-Rand] recently wrote in with his clever solution for capturing written notes and pushing them into Notion, but the hardware design and digitization workflow is flexible enough that it could be adapted to your specific needs — especially since he was good enough to release all the files required to build your own version.
Whether they are hand-written notes, old photographs, or legal documents, digitization boils down to taking a high resolution digital photo of the object and running it through the appropriate software. But getting good and consistent photos is the key, especially when you’re working your way through a lot of pages. [Spencer] started out just snapping pictures with his phone, but quickly found the process was less than ideal.
His custom scanning station addresses that first part of the problem: getting consistent shots. The images are captured using a Raspberry Pi 5 with attached Camera Module 3, while the 3D printed structure of the device makes sure that the camera and integrated lighting system are always in the same position. All he needs to do is place his notepad inside the cavity, hit the button, and it produces a perfect shot of the page.
Using a dedicated digitizing station like this would already provide better results than trying to freehand it with your phone or camera, but [Spencer] took things quite a bit farther. The software side of the project puts a handy user interface on the 5 inch touch screen built into the top of the scanner, while also providing niceties like a REST API and integration with the OpenAI Vision API for optical character recognition (OCR).
Those with an aversion to AI could certainly swap this out for something open source like Tesseract, but [Spencer] notes that not only is OpenAI’s OCR better at reading his handwriting, it spits out structured markdown-like data that’s easier to parse. From there it goes into the Notion API, but again, this could be replaced with whatever you use to collect your digital thoughts.
A device like this would go a long way towards answering a question we posed to the community back in January about the best way to digitize your documents.
2026-04-17 01:00:15
Information, it seems, flows at the speed of media. In the old days, information traveled with people on ships or horses, so if, say, a battle was won or lost, it could be months or even years before anyone back home knew what happened. While books and movable type let people store information, they still moved at the speed people moved. Before the telegraph, there were attempts to use things like semaphores to speed the flow of information, but those were generally limited to line-of-sight operations. Carrier pigeons were handy, but don’t really move much faster than people.
The telegraph helped, but people didn’t have telegraph stations in their homes. At least not ordinary people. But radio was different. It didn’t take long for every home to have a radio, and while the means of broadcasting remained in the hands of a few, the message could go everywhere virtually instantly. This meant news could go from one side of the globe to the other in seconds. It also meant rumors, fads, and what we might think of today as memes could, too.
You might think that things “going viral” is a modern problem, but, in reality, media sensations have always been with us. All that changes is the number of them and their speed.
One of the earliest viral media sensations dealt with William Floyd Collins, an unfortunate man who was exploring caves during the Kentucky Cave Wars.
Mammoth Cave in Kentucky had become a major tourist attraction. The accessible entrance to the cave was located on land owned by the Croghan family. The massive cave system had been made famous in the 19th century, and with the construction of a lock and dam nearby in 1906, Mammoth Cave became accessible to ordinary tourists.
However, the cave wasn’t completely under the Croghan land. There were also other caves that may or may not have been connected with Mammoth Cave. This led to fierce competition. The Croghan family suppressed information about exactly what land was over the cave. Meanwhile, other cave “owners” would intercept people heading for the cave, tell them that Mammoth Cave was closed, and “helpfully” direct them to another location.
By the 1920s, George Morrison blasted new entrances to the cave on non-Croghan land. There was fierce interest in finding new entrances to the cave or nearby caves to capture tourist money.
Floyd Collins found an entrance into what would become known as the “Great Crystal Cave” in 1917 and opened it to tourists in 1918. Unfortunately, the cave was hard to access, so it didn’t make much money.
Floyd had started entering caves in 1893 at the age of six. He discovered his first cave in 1910. But Great Crystal Cave was too far off the main road. He entered into a deal with three farmers who owned land closer to the main highway. If Floyd could find a suitable cave or, even better, an entrance to Mammoth Cave, he’d partner with them and create a mutually profitable tourist attraction.
Floyd found a hole in what would become known as Sand Cave. Some of the passages he had to move through were as tight as 9 inches, which, of course, would not be suitable for tourists, but they opened, apparently, into a large grotto. He was determined to expand the entrance to make the cave commercially viable.
In January of 1925, he was working in the cave when his gas lamp started to dim. He tried to leave, but while trying to move through a small passage, he knocked over his light, leaving him in total darkness.
In the dark, he put his foot against a seemingly stable wall and caused a shift that pinned his leg with a rock weighing nearly 30 pounds. He was also buried in gravel. At this point, he was 150 feet from the hole to the surface.
The next day, people noticed Floyd was missing, but no one would dare to follow him through the narrow passages. His younger brother finally got close enough to determine what happened. He was able to give Floyd food and water as plans for a rescue developed.
After four days in the cave, several people tried to pull Floyd out using a rope and a harness, but they only wound up injuring him. Meanwhile, the media had taken interest in the case, and the publicity drew hundreds of tourists and amateur spelunkers. Campfires and, possibly, the electric light that had been placed to give Floyd some light and warmth, melted ice inside the cave, creating puddles of water around the trapped man.
Two days after the failed rescue attempt, rain and the melting ice caused the cave passage to collapse, and the rescue team determined it was too dangerous to dig it back out after making an attempt to do so. They decided to dig straight down to reach Floyd.
Unfortunately, the cave drew air in so they decided they could not use mechanical diggers without risking suffocating Floyd. That meant humans would have to dig the 55-foot shaft to reach the victim. The initial estimate that 75 volunteers could dig the shaft in 30 hours proved optimistic, as conditions worsened and the hole grew deeper.
Someone disconnected the wires from the light bulb and connected them to an audio amplifier to detect signs of life from the victim. They believed the repetitive crackling noise meant he was breathing.
The light bulb went open on February 11th, twelve days after the incident started. Five days later, they reached his body. He had died and had been dead for several days.
You can find a well-done documentary from Remix Films in the video below. For a movie inspired by the event, check out the Billy Wilder film Ace in the Hole (1951) starring Kirk Douglas.
A newspaper reporter, William Miller, was on the scene and, being a small man, was able to actually help remove gravel from Floyd before the cave-in. His interview with the man from inside the cave won a Pulitzer Prize.
There was a time when this would have been only a sensational local story, but by the modern year of 1925, reports “went out on the wire” by telegraph and were picked up by newspapers worldwide. The nearest telegraph station was miles away, so two ham radio operators (9BRK and 9CHG) provided a link between the site, the newspaper, and the authorities.
The first broadcast radio station, KDKA, was only five years old, but stations provided news bulletins detailing the progress. Thanks to the media, crowds were reported to number in the tens of thousands. Eventually, the National Guard arrived to help control the crowds.
Vendors popped up to sell hamburgers and memorabilia like a macabre circus. As you can see in the video below, memorabilia about the event and Floyd Collins can be worth a pretty penny to collectors.
The whole thing became one of the three largest media events between World War I and World War II. The other two were Lindbergh’s transatlantic flight (1927) and the kidnapping of Lindbergh’s baby (1932). Oddly, Lindbergh was an acquaintance of Floyd’s and also flew news photos from the scene (although, reportedly, to the wrong newspaper).
While it wasn’t quite as big an event, Canada’s 1936 Moose River Gold Mine collapse was a similar situation and also received worldwide media attention. It has the distinction of being the first 24-hour radio coverage of a breaking news story in Canada.
These days, sensational news stories pop up everywhere. It seems as if they hardly get started when they are displaced by another one. But we submit that “going viral” isn’t a modern phenomenon. Only the speed at which it happens. Even an 1835 newspaper was able to spur a viral hoax.
Featured image: “Mammoth Cave Saltpeter Mine” by [Bpluke01]
