Year: 2020

Custom Reddit Keyboard Only Needs One Hand

March 17, 2020 by 12 Comments

Sometimes you might want to browse your favorite social media site while eating a sandwich, or throwing darts, or fending off an attacker with a sword. You know, normal things that might occupy only one of your hands. If you’ve ever found yourself in such a situation, then this custom Reddit keyboard could be for you.

Built by [jangxx], this little board is about as simple as it gets. Even if you aren’t looking for a way to browse /r/cooking while practicing your single-handed egg cracking technique, the same principles could be used to quickly throw together a macro keyboard for whatever your particular needs might be.

Inside the 3D printed enclosure is nothing more exotic than an Arduino Pro Micro and five Cherry MX Red switches. The switches have been wired directly to the GPIO pins on the Arduino, and a simple Sketch takes care of the rest. [jangxx] has written the code in such a way that you can easily define the mapping of USB HID keys to physical switches right at the top of the file, making it easy to reuse for your own purposes.

As simple as this project is, we really like the trouble that [jangxx] went through on the 3D printed key caps. The white up and down arrows allow you to navigate through the posts, and the center key selects the one you want to view. Since it’s for Reddit, naturally the red and blue buttons for rapid voting. When you want to go back to the list of posts, just hit the center button again.

Back in 2011 we saw a dedicated Reddit voting peripheral, but we think the addition of simple navigation keys makes this project a bit more compelling. Incidentally, if you can think of any other reason you might want a one-handed keyboard for browsing Reddit…we definitely don’t want to hear about it.

Northrop Grumman Tests Space Tow Truck

March 17, 2020 by 33 Comments

In the early days, satellites didn’t stick around for very long. After it was launched by the Soviet Union in 1957, it only took about three months for Sputnik 1 to renter the atmosphere and burn up. But the constant drive to push ever further into space meant that soon satellites would remain in orbit for years at a time. Not that they always functioned for that long; America’s Explorer 1 remained in orbit for more than twelve years, but its batteries died after just four months.

Of course back then, nobody was too worried about that sort of thing. When you can count the number of spacecraft in Earth orbit on one hand, what does it matter if one of them stays up there for more than a decade? The chances of a collision were so low as to essentially be impossible, and if the satellite was dead and wasn’t interfering with communication to its functional peers, all the better.

The likelihood of a collision steadily increased over the years as more and more spacecraft were launched, but the cavalier approach to space stewardship continued more or less unchanged into the modern era. In fact, it might have endured a few more decades if companies like SpaceX weren’t planning on mega-constellations comprised of thousands of individual satellites. Concerned over jamming up valuable near-Earth orbits with so much “space junk”, modern satellites are increasingly being designed with automatic disposal systems that help make sure they are safely deorbited even in the event of a system failure.

That’s good news for the future, but it doesn’t help us with the current situation. Thousands of satellites are in orbit above the planet, and they’ll need to be dealt with in the coming years. The good news is that many of them are at a low enough altitude that they’ll burn up on their own eventually, and methods are being developed to speed up the process should it be necessary to hasten their demise.

Unfortunately, the situation is slightly more complex with communications satellites in geosynchronous orbits. At an altitude of 35,786 kilometers (22,236 miles), deorbiting these spacecraft simply isn’t practical. It’s actually far easier to maneuver them farther out into space where they’ll never return. But what if the satellite fails or runs out of propellant before the decision to retire it can be made?

That’s precisely the sort of scenario the Mission Extension Vehicle (MEV) was developed for, and after a historic real-world test in February, it looks like this “Space Tow Truck” might be exactly what we need to make sure invaluable geosynchronous orbits are protected in the coming decades.

Continue reading “Northrop Grumman Tests Space Tow Truck” →

Can Lego Break Steel?

March 17, 2020 by 14 Comments

Betteridge’s Law of Headlines holds that any headline ending in a question mark can be answered with a resounding “No”. But as the video below shows, a Lego machine that twists steel asunder is not only possible, it’s an object lesson in metal fatigue. Touché, [Betteridge].

In pitting plastic against metal, the [Brick Experiment Channel] relied on earlier work with a machine that was able to twist a stock plastic axle from the Technics line of parts like a limp noodle. The steel axle in the current work, an aftermarket part that’s apparently no longer available, would not prove such an easy target.

Even after beefing up the test stand with extra Technics struts placed to be loaded in tension, and with gears doubled up and reinforced with extra pins, the single motor was unable to overcome the strength of the axle. It took a second motor and a complicated gear train to begin to deform the axle, but the steel eventually proved too much for the plastic to withstand. Round Two was a bit of a cheat: the same rig with a fresh axle, but this time the motor rotation was constantly switched. The accumulated metal fatigue started as a small crack which grew until the axle was twisted in two.

The [Brick Experiment Channel] is a fun one to check out, and we’ve featured them before. Along with destructive projects like this one, they’ve also got fun builds like this Lego playing card launcher, a Technic drone, and a Lego submarine.

Continue reading “Can Lego Break Steel?” →

Using Additives For Better Performing Epoxy

March 17, 2020 by 13 Comments

Epoxy resins are an important material in many fields. Used on their own as an adhesive, used as a coating, or used in concert with fiber materials to make composites, their high strength and light weight makes them useful in many applications. [Tech Ingredients] decided to explore how combining basic epoxy resin with various additives can make it perform better in different roles.

The video primarily concerns itself with explaining different common additives to epoxy resin mixtures, and how they impact its performance. Adding wood flour is a great way to thicken epoxy, allowing it to form a bead when joining two surfaces. Microbeads are great to add if you’re looking to create a sandable filler. Other additive like metal powders lend the mixture resistance to degradation from UV light, while adding dendritic copper creates a final product with high thermal conductivity.

The video does a great job of not only explaining the additives and their applications, but also shares a few handy tips on best workshop practices. Things like triple-gloving and observing proper mixing order can make a big difference to your workflow and lead to better results.

We’ve seen practical applications of epoxy mixes before – with epoxy granite being a particularly popular material. Video after the break.

Continue reading “Using Additives For Better Performing Epoxy” →

Patterned Plywood Makes For Attractive Speakers

March 16, 2020 by 12 Comments

In the matter of audio, we’re well past the reign of the home hi-fi and the boombox. If you’re not listening on headphones or directly on your phone, you’ve got a brick-sized Bluetooth speaker pumping out the tunes. Still a fan of the old-school, [Amanda Ghassaei] built some bookshelf speakers with a hip aesthetic.

First, the speaker enclosures were designed in WinISD, a software package specifically made for the task. For given woofers and tweeters, it helps get the enclosure and port sizes in the correct range for good sound. Panels were then fabricated out of plywood to make the enclosures. The plywood was cut and reformed several times to make the panels, using the pattern from the multiple plies to create the zig-zag look. Audio wise, a class D amplifier takes in line-level signals, before pumping them out to a woofer and tweeter through a custom designed crossover network.

It’s a tidy build, and we’d love to experiment ourselves with the fancy patterned plywood technique. Getting your enclosure design right can make a big difference to sound quality, as we’ve seen before. Video after the break.

Continue reading “Patterned Plywood Makes For Attractive Speakers” →

Dissecting China-Sourced Vintage HP 1970s ICs: Genuine Or Not?

March 16, 2020 by 10 Comments

While repairing a real-time clock module for a 1970s HP computer that had been damaged by its leaky internal battery, [CuriousMarc] began to suspect that maybe the replacement clock chips which he had sourced from a seller in China were the reason why the module still wasn’t working after the repairs. This led him down the only obvious path: to decap and inspect both the failed original Ti chip and the replacement chip.

The IC in question is the Texas Instruments AC5948N (along with the AC5954N on other boards), which originally saw use in LED watches in the 1970s. HP used this IC in its RTC module, despite it never having been sold publicly. This makes it even more remarkable that a Chinese seller had the parts in stock. As some comments on the YouTube video mention, back then there wasn’t as much secrecy around designs, and it’s possible someone walked out of the factory with one of the masks for this chip.

Whether true or not, as the video (also included after the break) shows, both the original 1970s chip and the China-sourced one look identical. Are they original stock, or later produced from masks that made their way to Asia? We’ll probably never know for sure, but it does provide an exciting opportunity for folk who try to repair vintage equipment.

Continue reading “Dissecting China-Sourced Vintage HP 1970s ICs: Genuine Or Not?” →