Roman numerals are, by modern standards, a bit unusual. By virtue of using designations for both 5 and 10, and not scaling well to higher numbers, they’ve fallen out of favor outside of some specific uses. One of those is in time keeping, in which many clocks use the classical numerals instead of the more popular Arabic replacements. [Nicola]’s clock does too, albeit in a rather unusual way.
A diagram of the clock displaying the times 18:40 and 23:04.
The build begins with a faux-neon palm tree LED decoration, which is gutted and refitted with a WS2812B LED strip, run by an Arduino Nano. An RTC is used to keep accurate time, and the time is set by running a one-off program to initialise the clock.
To tell the time, the LEDs are color coded. However, instead of using a binary representation that many can find unfamiliar, colors are chosen instead to correspond to Roman numerals. Blue, green, red and yellow are chosen to represent 1, 5, 10, and 50, or I, V, X, and L respectively. The Github has more details for the curious. The clock uses 24 hour time, and we think we’ve figured out how the display works – with hours on the left and minutes on the right.
In theory, you shouldn’t need any help to develop a software-defined radio (SDR) application. But in real life you really don’t want to roll your own code every time to read the IQ samples, perform various transformations on them, and then drive audio output. At worst, you’ll use some libraries (perhaps GNU Radio) but usually, you’ll use some higher-level construct such as GNU Radio Companion (GRC). GRC is a bit heavyweight, though, so if you’ve found it daunting before, you might check out some of the material on the LuaRadio website.
We’ve looked at LuaRadio several years ago, but it has undergone a lot of changes since then and has some excellent documentation. Like Lua itself, LuaRadio emphasizes fast scripting. It supports quite a few pieces of common hardware and nearly anything that feeds data through a soundcard.
Americans love their coffee. The Brits adore their tea. In South America, the number one way to get through the day is with yerba mate, a tea made from the yerba plant. It is typically shared in a social setting, with one person preparing the beverage for everyone to enjoy. Although caffeine certainly deserves a ceremony, it never needs one. Hit the streets and you’ll see people everywhere with a thermos under one arm, keeping water hot and ready to refill the cup of mate in their hand.
The Stanley vacuum thermos is quite a popular choice for drinkers on the go, but the Argentinian government recently placed new restrictions foreign imports. [Roni Bandini] decided to build a minimum viable mate machine so he always has perfectly hot water on tap.
An Arduino Nano heats the water and displays the rising temperature on an LCD screen. When the temperature is just right, the display asks for your cup. An ultrasonic sensor detects the cup and dispenses a certain amount of water determined in the sketch. Yerba leaves can be used a few times before losing their flavor, so the machine keeps track and lets him know when it’s time to replace them. You can sip on a brief demo after the break.
It takes a lot of work to get a functional PCB business card that’s thin, cheap, and robust enough to be practical. If you can even blink a few LEDs on the thing and still hand them out with a straight face, you’ve done pretty well for yourself. So you can imagine our surprise when [George Hilliard] wrote in to tell us about his $3 business card computer that boots into a functioning Linux environment. If this were a bit closer to April, we might have figured it was just a joke…
Of course it helps that, as an embedded systems engineer, [George] literally does this kind of thing for a living. Which isn’t to say it was easy, but at least he keeps close enough tabs on the industry to find a suitable ARM solution at a price that makes sense, namely the Allwinner F1C100s. This diminutive chip offers both RAM and CPU in a single package, which greatly simplifies the overall design and construction of the card.
With a root filesystem that weighs in at just 2.4 MB, the environment on the card is minimal to say the least. There’s no networking, limited I/O, and forget about running any heavy software. But it does boot in about six seconds, and [George] managed to pack in a MicroPython interpreter and a copy of the classic Unix dungeon crawler rogue.
Oh yeah, and it also has his resume and some samples of his photography onboard. It is, after all, a business card. All the user has to do is plug it into the USB port of their computer and wait for the virtual serial port to pop up that will let them log into the system running on the card. It also shows up as a USB Mass Storage device for recipients who might not be quite as adept at the command line.
In addition to the high-level documentation for this project, [George] has also prepared a deeper write-up that goes into more technical detail for anyone who might be looking to follow in his footsteps. Thanks to all of the source code that he’s made available, it should be a lot easier for the next person to get their own disposable pocket computer up and running.
We’ve seen all manner of electronic business cards over the years, but never anything quite like this. Which, of course, is quite the point. If you’re ever given a business card that doubles as a computer running a full-fledged operating system on it, you aren’t likely to forget it anytime soon.
[8BitsAndAByte] caved in to increasing holiday madness and bought the cutest little Christmas tree. A special tree deserves special decorations, so they packed it with NeoPixels that turn from red to green and back again one by one. Here’s where the trendiness comes in: the speed at which they change is determined by the popularity of “Christmas” as a search term.
The NeoPixels are controlled by a Raspberry Pi 3B+ that uses PyTrends to grab a value from Google Trends once an hour. The service returns a value between 0 to 100, where 100 means the search term is extremely popular, and 0 means it’s probably the dead of January. Each NeoPixel is wired to the underside of a translucent printed gift box that does a great job of diffusing the light.
You know how Christmas trees have a tendency to stick around well into the new year? This one might last even longer than usual, thanks to the bonus party mode. Press the arcade button on the box cleverly disguised as a present, and the lights change from red to green and back at warp speed while the speaker inside blasts the party anthem of your choice. Be sure to check out the demo/build video waiting for you under after the break.
How could this little tree get any more special? Well, a rotating platform couldn’t hurt.
Over the years, humans have come up with four forces that can be used to describe every single interaction in the physical world. They are gravity, electromagnetism, the weak nuclear force that causes particle decay, and the strong nuclear force that binds quarks into atoms. Together, these have become the standard model of particle physics. But the existence of dark matter makes this model seem incomplete. Surely there must be another force (or forces) that explain both its existence and the reason for its darkness.
Hungarian scientists from the Atomki Nuclear Research Institute led by Professor Attila Krasznahorkay believe they have found evidence of a fifth force of nature. While monitoring an excited helium atom’s decay, they observed it emitting light, which is not unusual. What is unusual is that the particles split at a precise angle of 115 degrees, as though they were knocked off course by an invisible force.
The scientists dubbed this particle X17, because they calculated its mass at 17 megaelectronvolts (MeV). One electron Volt describes the kinetic energy gained by a single electron as it moves from zero volts to a potential of one volt, and so a megaelectronvolt is equal to the energy gained when an electron moves from zero volts to one million volts.
What Are Those First Four, Again?
Let’s start with the easy one, gravity. It gives objects weight, and keeps things more or less glued in place on Earth. Though gravity is a relatively weak force, it dominates on a large scale and holds entire galaxies together. Gravity helps us work and have fun. Without gravity, there would be no water towers, hydroelectric power plants, or roller coasters.
The electromagnetic force is a two-headed beast that dominates at the human scale. Almost everything we are and do is underpinned by this force that surrounds us like an ethereal soup. Electricity and magnetism are considered a dual force because they work on the same principle — that opposite forces attract and like forces repel.
This force holds atoms together and makes electronics possible. It’s also responsible for visible light itself. Each fundamental force has a carrier particle, and for electromagnetism, that particle is the photon. What we think of as visible light is the result of photons carrying electrostatic force between electrons and protons.
The weak and strong nuclear forces aren’t as easy to grasp because they operate at the subatomic level. The weak nuclear force is responsible for beta decay, where a neutron can turn into a proton plus an electron and anti-neutrino, which is one type of radioactive decay. Weak interactions explain how particles can change by changing the quarks inside them.
The strong nuclear force is the strongest force in nature, but it only dominates at the atomic scale. Imagine a nucleus with multiple protons. All those protons are positively charged, so why don’t they repel each other and rip the nucleus apart? The strong nuclear force is about 130x stronger than the electromagnetic force, so when protons are close enough together, it will dominate. The strong nuclear force holds both the nucleus together as well as the nucleons themselves.
The Force of Change
Suspicion of a fifth force has been around for a while. Atomki researchers observed a similar effect in 2015 when they studied the light emitted during the decay of a beryllium-8 isotope. As it decayed, the constituent electrons and positrons consistently repelled each other at another strange angle — exactly 140 degrees. They dubbed it a “protophobic” force, as in a force that’s afraid of protons. Labs around the world made repeated attempts to prove the discovery a fluke or a mistake, but they all produced the same results as Atomki.
Professor Attila Krasznahorkay and his team published their observations in late October, though the paper has yet to be peer-reviewed. Now, the plan at Atomki is to observe other atoms’ decay. If they can find a third atom that exhibits this strange behavior, we may have to take the standard model back to the drawing board to accommodate this development.
So what happens if science concludes that the X17 particle is evidence of a fifth force of nature? We don’t really know for sure. It might offer clues into dark matter, and it might bring us closer to a unified field theory. We’re at the edge of known science here, so feel free to speculate wildly in the comments.
WS2812Bs, or NeoPixels, or whatever else you call them brought full-color LEDs to maker projects a meter at a time in recent years. Hooked up to a microcontroller, they make creating vibrant, full-color glowables a cinch. They won’t work on their own though, and a some point you want to ditch the dev board and let the blinking stand on its own two feet. Enter the USB LED Otter.
This small square of PCB lets you plug an LED strip directly into a USB port. The PCB itself has four traces on the back that mate with any USB port, and three pads for soldering the strip’s ground, 5 V line, and data. An STM32F072 microcontroller serves as the brains of the operation, packing plenty of horsepower and full compatibility with USB 2.0.
Code is flashed to the chip over USB using Device Firmware Upgrade (DFU) and once written the strip can then be driven by jamming the string into a suitably powerful USB wall charger. The woman behind the build, [Jana Marie], has mentioned that Open Pixel Control could be implemented but that may be an exercise left to the reader.
It’s a useful little tool, and one that promises to do even more with a little more development. Whipping up a few boards should be an easy task for anyone with a reflow oven and a free weekend. Oh, and if you’re tired of the WS2812? There’s other addressable LEDs out there, too!
