It’s easy to see why LEDs largely won out over neon bulbs for pilot light applications. But for all the practical utility of LEDs, they’re found largely lacking in at least one regard over their older indicator cousins: charm. Where LEDs are cold and flat, the gentle orange glow of a neon lamp brings a lot to the aesthetics party, especially in retro builds.
But looks aren’t the only thing these tiny glow lamps have going for them, and [David Lovett] shows off some of the surprising alternate uses for neon lamps in his new video. He starts with an exploration of the venerable NE-2 bulb, which has been around forever, detailing some of its interesting electrical properties, like the difference between the voltage needed to start the neon discharge and the voltage needed to maintain it. He also shows off some cool neon lamp tricks, like using them for all sorts of multi-vibrator circuits without anything but a few resistors and capacitors added in. The real fun begins when he breaks out the MTX90 tube, which is essentially a cold cathode thyratron. The addition of a simple control grid makes for some interesting circuits, like single-tube multi-vibrators.
The upshot of all these experiments is pretty clear to anyone who’s been following [David]’s channel, which is chock full of non-conventional uses for vacuum tubes. His efforts to build a “hollow state” computer would be greatly aided by neon lamp circuits such as these — not to mention how cool they’d make everything look.
Continue reading “Neon Lamps — Not Just For Pilot Lights” →
Here’s a history quiz: What architecture did the first C++ compiler target? Of course, it is a trick question. The original C++ — known then as C with classes — compiler wrote out standard C code that you then compiled for whatever your target was. This has a lot of advantages since C compilers are everywhere. Now we are seeing a similar approach to bring C23 to the world with Cake. Cake can translate C23 or other versions to C99 which you can then compile with normal compilers.
While the old C++ compiler, cfront, needed special steps to compile (since it was built using C++), you can build cake for Windows or Linux easily. However, it can also be built with emscripten and you can try it yourself in your web browser.
Continue reading “C23 Programming For Everyone” →
Running a radio station is, on the face of it, a straightforward technical challenge. Build a studio, hook it up to a transmitter, and you’re good to go. But what happens when your station is not a single Rebel Radio-style hilltop installation, but a national chain of transmitter sites fed from a variety of city-based studios? This is the problem facing the BBC with their national UK FM transmitter chain, and since the 1980s it has been fed by a series of NICAM digital data streams. We mentioned back in 2016 how the ageing equipment had been replaced with a modern FPGA-based implementation without any listeners noticing, and now thanks to [Matt Millman], we have a chance to see a teardown of the original 1980s units. The tech is relatively easy to understand from a 2020s perspective, but it still contains a few surprises.
In each studio or transmitter site would have been a 19″ rack containing one of these units — a card frame with a collection of encoder or decoder cards. These are all custom-made by the BBC’s engineering department to a very high standard, and use period parts such as the familiar Z80 microprocessor and some Philips digital audio chips, which followers of high-end consumer audio may recognize. As you’d expect for a mission critical device, many of the functions are duplicated for redundancy, with their outputs compared to give warning of failures.
The surprise comes in the NICAM encoder and decoder — it’s a custom LSI chip made exclusively for the BBC. This indicates the budget available to the national broadcaster, and given that these units have in some cases been working for over 35 years, we’re guessing that the license payers got their money’s worth.
You can read about the original switch-over in 2016, and a little more about NICAM, too.
We’ll admit it. We like the results of resin 3D printing, but we don’t always care for the mess. We aren’t alone, and a common issue is to have drips of resin on your LCD screen — a potential disaster. You ought to have a screen protector, but yeah… you should back up hard drives, too. [Jessy] has the same problem and he has heard that you can easily clean cured resin from the screen using wood glue. Does it work? Check out the results of three glues in the video below.
We winced to see glue going on the screens. [Jessy] cured some resin on the screens deliberately for a test. He used Elmer’s wood glue, Gorilla wood glue, and Titebond II wood glue. While there is a bit of a price difference between the options, they are all fairly inexpensive.
Continue reading “Resin Cleanup: A Sticky Situation” →
It’s an unfortunate consequence of growing older, that no longer are you able to read the print on a SOT-23 package or solder a QFN without magnification. Your eyes inexorably start to fail, and to have any hope of continuing a set of reading glasses is required. We have this in common with [Niklas Roy], who noticed while shopping for cheap reading glasses that their lenses were of surprisingly good quality. The result of this observation was a stereoscope made from card and a few euros worth of eyewear.
In the tradition of [Niklas]’ work it has a high level of attention to detail, which manifests itself here in a parametric web-based template generator to produce a result tailored to your glasses. It’s a fairly straightforward trapezoid shape, with a compound lens made from two sets of glasses drilled and held back-to-back with zip ties.
It served as a project for a group of children, and of course because stereo cameras are a relative rarity he also investigated taking his own pictures by moving a smartphone for left and right eye perspectives. It seems the youngsters had a lot of fun.
These lenses hadn’t come up on our radar until now, but like many goodies in a dollar store they’re certainly something to take a look at. Maybe not as a stereoscope for everyone though, some of us can’t see what the fuss is about.
It seems obvious that if you dig or drill into the soil, at some point you will hit groundwater. Drill deep enough and you will reach an aquifer containing enormous amounts of fresh water. After this you can just pump water out of these wells and you will have fresh water aplenty. Or so was the thinking among many for the longest time. As enormous the fresh water reserves in the form of groundwater are – with most liquid fresh water being groundwater – we can literally empty them faster than that they’ll refill.
As the Dust Bowl disaster painfully showed in the 1930s and drought along with surface subsidence issues as in e.g. California’s Central Valley shows today is that we cannot simply use the soil and groundwater and expect no consequences. While the 19th century saw many fresh settlers to the West’s arid and semi-arid regions like California believe in the ‘Rain follows the plow‘ mysticism, the 20th century and these first few decades of the 21st century taught us that tilling the soil and drawing groundwater for irrigation does not change an arid climate into a lush one.
Perhaps ironically, even with increasing droughts, most human settlements use stormwater drainage and combined sewage systems to carry rainwater away, rather than letting the groundwater recharge naturally. Fortunately, more and more regions these days are seeing the necessity of managing groundwater.
Continue reading “Groundwater: Management Of A Much Neglected Lifeline” →
Join us on Wednesday, September 14 at noon Pacific for the Heavy Engineering Hack Chat with Andy Oliver!
Here at Hackaday, we focus mainly on engineering at the small end of the spectrum. Millimeter waves, nearly microscopic SMD components, nanoscale machines like MEMS accelerometers, and silicon chips with features that measure in the nanometer range. We’ve all become pretty good at wrapping our heads around problems at the wee end of the spectrum.
And while all that tiny stuff is great, there’s a whole, big world out there to explore, with big engineering to solve big problems. Think of things like dam spillways, lift bridges, and canal locks — big stuff that still has to move, and has to do it safely and efficiently. Those are problems that demand an entirely different way of thinking, and skills that not a lot of us have.
Andy Oliver works in the world of big, movable structures, designing control systems for them. He’ll drop by the Hack Chat to discuss the engineering that not only makes these structures work but also keeps them safe and reliable. If you’ve ever wondered how big things work, you won’t want to miss this one.
Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, September 14 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.