Simple But Stylish Numitron Clock Can Display Time, Date And Temperature

November 22, 2021 by Robin Kearey 6 Comments

While it seems like Nixie tubes get all the attention when it comes to making retro-style displays, there are plenty of other display technologies that can make a good-looking retro design. Take the Numitron tube: introduced by RCA in the early 1970s, these display tubes might look superficially similar to Nixies but work in a completely different way. The Numitron uses incandescent elements that make up seven-segment displays.

The main advantage Numitrons have over Nixes is that they don’t require a high-voltage supply, which makes them much easier to hook up to modern low-voltage electronics. [mircemk] used this to his advantage when he built a simple clock using four numitrons that can display the time, the date, and the ambient temperature.

The brains of the device are formed by an Arduino Nano coupled with a DS3231 battery-backed real-time clock module. For now, the time has to be synchronized by connecting the Arduino to a PC and reprogramming it, but [mircemk] has plans to update the design with pushbuttons to allow the user to set the time manually.

Four shift registers are all that’s needed to interface the microcontroller to the display tubes, thanks to their low-voltage operation. They do need quite a lot of current, so [mircemk] used the high-power TPIC6C595 instead of a regular 74HC595 chip. We wonder if the tubes’ high power consumption could be the reason why the temperature in his lab seems to hover around 30 °C.

A simple but stylish plastic enclosure completes the design. Since Numitron tubes are relatively low-cost and no other specialized components are needed, this could be one of the cheapest and easiest ways to make a retro display tube clock. Although we’ve seen a couple of Numitron clocks and even watches before, today’s build is a great example of how simple such a design can actually be. Continue reading “Simple But Stylish Numitron Clock Can Display Time, Date And Temperature” →

PFAS: The Organofluorines Your Biochemist Warned You About

November 22, 2021 by Maya Posch 49 Comments

Sometimes it begins to feel like a tradition that a certain substance or group of substances become highly popular due to certain highly desirable chemical or physical properties, only for these chemicals then to go on to turn out to form a hazard to the biosphere, human life, or both. In the case of per- and polyfluoroalkyl substances (PFAS) it’s no different. Upon the discovery that a subgroup of these – the fluorosurfactants – have the ability to reduce water surface tension significantly more than other surfactants, they began to be used everywhere.

Today, fluorosurfactants are being used in everything from stain repellents to paint, make-up, and foam used by firefighters. In a recent study of 231 cosmetic products bought in the US and Canada (Whitehead et al., 2021), it was found that all of them contained PFAS, even when not listed on the packaging. The problematic part here is that PFASs are very stable, do not decay after disposal, and bioaccumulate in the body where they may have endocrine-disrupting effects.

Some areas have now at least partially banned PFAS, but the evidence for this is so far mixed. Let’s review what we do know at this point, and which alternatives we have to continuing to use these substances. Continue reading “PFAS: The Organofluorines Your Biochemist Warned You About” →

Retrotechtacular: Junior Missile Men Of The 1960s

November 22, 2021 by Dan Maloney 30 Comments

Just like the imaginative kids depicted in “Junior Missile Men in Action,” you’ll have to employ a fair bit of your own imagination to figure out what was going on in the original film, which seems to have suffered a bit — OK, a lot — from multiple rounds of digitization and format conversion. [GarageManCave] tells us he found the film on a newsgroup back in the 1990s, but only recently uploaded it to YouTube. It’s hard to watch, but worth it for anyone who spent hours building an Estes model rocket and had that gut-check moment when sliding it onto the guide rail and getting it ready for launch. Would it go? Would it survive the trip? Or would it end up hanging from a tree branch, or lost in the high grass that always seemed to be ready to eat model rockets, planes, Frisbees, or pretty much anything that was fun?

Model rocketry was most definitely good, clean fun, even with the rotten egg stink of the propellant and the risk of failure. To mitigate those risks, the West Covina Model Rocket Society, the group the film focuses on, was formed in the 1960s. The boys and girls pictured had the distinct advantage of living in an area where many of their parents were employed by the aerospace industry, and the influence of trained engineers shows — weekly build sessions, well-organized range days, and even theodolites to track the rockets and calculate their altitude. They even test-fired rockets from miniature silos, and mimicked a Polaris missile launch by firing a model from a bucket of water. It was far more intensive and organized than the early rocketry exposure most of us got, and has the look and feel of a FIRST robotics group today.

Given the membership numbers the WCMRS boasted of in its heyday, and the fact that model rocketry was often the “gateway drug” into the hacking lifestyle, there’s a good chance that someone in the Hackaday community got their start out in that park in West Covina, or perhaps was even in the film. If you’re out there, let us know in the comments — we’d love to hear a first-hand report on what the club was like, and how it helped you get started.

Continue reading “Retrotechtacular: Junior Missile Men Of The 1960s” →

Blue Origin Rolls Out Test Article For Next-Gen Rocket

November 22, 2021 by Tom Nardi 28 Comments

By any metric you care to use, this is a very exciting time for America’s space program. NASA is refocusing their efforts towards the Moon and beyond, SpaceX is launching routine crew and cargo flights to the International Space Station with reusable rockets, and if you’ve got deep enough pockets, there are now multiple companies offering suborbital pleasure trips requiring little more than a few hours worth of training. It’s taken longer than many people had hoped, but it seems we’re finally making the confident strides necessary to truly utilize space’s vast resources.

But things are just getting started. A new generation of massive reusable rockets are currently being developed, which promise to make access to space cheaper and faster than ever before. We’ve seen quite a bit of SpaceX’s Starship, thanks in no small part to the dramatic test flights that the media-savvy company has been regularly live streaming to YouTube. But Blue Origin, founded by Amazon’s Jeff Bezos, has been far more secretive about their New Glenn. That is, until now.

On November 8th, Blue Origin rolled out their GS1 simulator for the New Glenn’s first stage. This stand-in for the real rocket will never fly, but it’s designed to perfectly recreate the dimensions, center of gravity, and mass, of the real thing. Ground teams will use the GS1 to practice safely transporting the booster, which is approximately half the length of the Saturn V, from their production facility to Launch Complex 36 (LC-36) at Cape Canaveral. It will also be used to test the fit and function of various pieces of ground support equipment, and eventually, the second stage stacking procedure.

For the uninitiated, it might seem like this is a lot of fuss over what’s ultimately just a hollow metal tube. But the introduction of a test article such as this has traditionally been a major milestone during the design and construction of rockets and spacecraft, dating back to the “boilerplate” test capsules used during the Mercury, Gemini, and Apollo programs; a sure sign that what was just an idea is now becoming a reality.

Continue reading “Blue Origin Rolls Out Test Article For Next-Gen Rocket” →

Tomatoes Are Not Guncotton

November 22, 2021 by Lewin Day 14 Comments

[Integza] hates tomatoes, but loves rocketry. Thus, he decided to see if he could process his most-loathed fruit into some sort of rocket fuel, or at least something relatively flammable. The experiment ended poorly, but the science behind it is interesting.

The basic idea is that tomatoes are largely made up of water, sugar, and cellulose. Thus, if you nitrate that cellulose, it becomes nitrocellulose, also known as guncotton. Guncotton is was once used to replace gunpowder in firearms, though today it’s often used by magicians to create ashless flashes of flame.

To achieve this, [Integza] first attempted to make regular guncotton using a 50:50 mixture of nitric acid and sulfuric acid. The cotton was then neutralized with a baking soda and water mixture to remove excess acid, and the cotton dried. Once tested, it burned quickly as you’d expect from guncotton.

After removing the sugars from tomatoes with water, soap, hydrogen peroxide, and bleach, the tomatoes were then dried to remove excess water before also getting the acid treatment. They were then similarly neutralized, dried, and tested. One tomato did burn rather quickly, while the others merely fizzled.

One of the reasons behind this may have been due to the composition of the tomatoes. Tomatoes often consist of a mixture of cellulose, hemicellulose, and lignin, these latter components are known for producing inferior guncotton. The ramshackle preparation may have had some effect on the results. Let’s just say and it’s not advisable to work with fuming acids without protective gear and a fume hood, either.

The video’s title claims that the tomatoes were turned into rocket fuel, which is far beyond the actual results of the experiment. However, with some more advanced chemical processing, we could certainly see the fruit becoming a mite more flammable than it was. You’re probably better off just sticking to straight cotton though, for the best results. Video after the break.

Continue reading “Tomatoes Are Not Guncotton” →

Arduino Plays The Glasses

November 22, 2021 by Al Williams 8 Comments

Have you ever been on a city street and seen a busker playing music on glasses? Each glass has a different amount of water and produces a different note when tapped. [Cyberlab] must have seen them and created an Arduino robot to play tunes on glasses. You can see the result in the video below.

If we had done this, we might have had a solenoid per glass or used some linear component like a 3D printer axis to pick different glasses. [Cyberlab] did something smarter. The glasses go in a circle and a stepper motor points at the correct glass and activates a solenoid. The result is pretty good and it is a lot simpler than any of our ideas.

If you aren’t musically inclined, you might wonder how you’d program the songs. There’s an example of taking a music box score from a website — apparently, there are lots of these — and removing any polyphony from it. The site mentioned even has an editor where you can import MIDI files and work with them to produce a music box strip that you could then convert. Then you encode each note as a number from 0 to 6.

Of course, you also have to fill your glasses with the right amount of water. A piano tuning phone app should be useful. We’ve seen this done in a linear fashion before. You can even use a single glass for many notes with a little ingenuity.

Continue reading “Arduino Plays The Glasses” →

Slick Keyboard Built With PCB Magic

November 21, 2021 by Dave Rowntree 21 Comments

Sometimes a chance conversation leads you to discover something cool you’ve not seen before, and before you know it, you’re ordering parts for yet another hardware build. That’s what happened to this scribe the other day when chatting on some random discord, to QMK maintainer [Nick Brassel aka tzarc] about Djinn, a gorgeous 64-key split mechanical keyboard testbed. It’s a testbed because it uses the newest STM32G4x microcontroller family, and QMK currently does not have support for this in the mainline release. For the time being, [Nick] maintains a custom release, until it gets merged.

Hardware-wise, the design is fabulous, with a lot of attention to detail. We have individual per-key RGB LEDs, RGB underglow, a rotary encoder, a five-way tactile thumb switch, and a 240×320 LCD per half. The keyboard is based on a three PCB stack, two of which are there purely for structure. This slick design has enough features to keep a fair few of us happy.

Interestingly, when you look at the design files (KiCAD, naturally) [Nick] has chosen to take a mirrored approach to the PCB. That means the left and right sides are actually the same PCB layout. The components are populated on different sides of the PCB depending on which half you’re looking at! By mirroring footprints on both PCB sides, and hooking everything up in parallel, it’s possible to do it all with a single master layout.

This is a simple but genius idea that this scribe hadn’t come across before (the shame!) Secondarily it keeps costs down, as your typical Chinese prototyping house will not deal in PCB quantities below five, so you can make two complete keyboards on one order, rather than needing two orders to make five. (Yes, there are actually three unique PCBs, but we’re simplifying the situation, ok?)

Now, if only this pesky electronics shortage could abate a bit, and we could get the parts to build this beauty!

Obviously, we’ve covered many, many keyboards over the years. Here’s our own [Kristina’s] column all about the things. If you need a little help with your typing skills, this shocking example may be the one for you. If your taste is proper old-school clackers, there’s something for everyone.