Fit Your LCDs With Lenses For That Vintage CRT Look

For as big, bulky, and power-hungry as they were, CRTs were an analog joy of the early days of TV, video games, and computers. The crackling high-voltage, the occasional whiff of ozone, the whizzing electrons lancing through a vacuum to excite a phosphorescent image — by comparison, thin-film LCDs are sterile and boring.

Sadly, CRTs are getting harder to come by these days, and at the extreme ends of the size spectrum, may never have been available at all. Thankfully, if your project demands a retro CRT look, fitting your LCD with a custom lens might just do the trick. The link leads to the first article in a series by [jamhamster] on the travails of lensmaking, which even when not practiced for precision lens production can still be tricky. After going through the basics of material selection — acrylic, but not cold-formed, please; such sheets have internal stresses that tend to express themselves as cracks while grinding. The grinding method is as ingenious as it is simple: a blank is fitted to a flat arbor and ground down by spinning it against a belt sander, on the side without the platen. A little WD40 for lubrication and thermal management helped while progressing to finer grit belts, with a final treatment using plastic polish yielded a shape very reminiscent of an old CRT face. There’s a Twitter video that shows the simulated CRT.

Further installments of the series detail the optical properties of these lenses,  options for bonding them to an LCD, and tying all the steps into a coherent method. We think the results speak for themselves, and suspect that these “emulated” CRTs often draw a double-take.

Thanks to [John] for the tip.

Put The Perfect Point On Your Tungstens With This Die Grinder Attachment

Aspiring TIG welders very quickly learn the importance of good tungsten electrode grinding skills. All it takes is a moment’s distraction or a tiny tremor in the torch hand to plunge the electrode into the weld pool, causing it to ball up and stop performing its vital function. Add to that the fussy nature of the job — tungstens must only be ground parallel to the long axis, never perpendicular, and at a consistent angle — and electrode maintenance can become a significant barrier to the TIG beginner.

A custom tungsten grinder like this one might be just the thing to flatten that learning curve. It comes to us by way of [The Metalist], who turned an electric die grinder into a pencil sharpener for tungsten electrodes. What we find fascinating about this build is the fabrication methods used, as well as the simplicity of the toolkit needed to accomplish it. The housing of the attachment is built up from scraps of aluminum tubing and sheet stock, welded together and then shaped into a smooth, unibody form that almost looks like a casting. Highlights include the mechanism for adjusting the angle of the grind as well as the clever way to slit the body of the attachment so it can be clamped to the nosepiece of the die grinder. We also thought the inclusion of a filter to capture tungsten dust was a nice touch; most TIG electrodes contain a small amount of lanthanum or thorium, so their slight radioactivity is probably best not inhaled.

We love builds like this that make a tedious but necessary job a little quicker and easier to bear, and anything that stands to make us a better welder — from simple purpose-built fixtures to large-scale rotary tables — is OK in our book.

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Precision Optics Hack Chat With Jeroen Vleggaar Of Huygens Optics

Join us on Wednesday, December 2nd at noon Pacific for the Precision Optics Hack Chat with Jeroen Vleggaar!

We sometimes take for granted one of the foundational elements of our technological world: optics. There are high-quality lenses, mirrors, filters, and other precision optical components in just about everything these days, from the smartphones in our pockets to the cameras that loom over us from every streetlight and doorway. And even in those few devices that don’t incorporate any optical components directly, you can bet that the ability to refract, reflect, collimate, or otherwise manipulate light was key to creating the electronics inside it.

The ability to control light with precision is by no means a new development in our technological history, though. People have been creating high-quality optics for centuries, and the methods used to make optics these days would look very familiar to them. Precision optical surfaces can be constructed by almost anyone with simple hand tools and a good amount of time and patience, and those components can then be used to construct instruments that can explore the universe wither on the micro or macro scale.

Jeroen Vleggaar, know better as Huygens Optics on YouTube, will drop by the Hack Chat to talk about the world of precision optics. If you haven’t seen his videos, you’re missing out!

When not conducting optical experiments such as variable surface mirrors and precision spirit levels, or explaining the Double Slit Experiment, Jeroen consults on optical processes and designs. In this Hack Chat, we’ll talk about how precision optical surfaces are manufactured, what you can do to get started grinding your own lenses and mirrors, and learn a little about how these components are measured and used.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, December 2 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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[Ben Krasnow]’s Take On DIY Air Bearings

We’ve got to admit that watching [Ben Krasnow]’s new video on air bearings is tough. We found our eyes constantly checking the spherical air bearing in the foreground, which for the first eight minutes of the video just kept going. It was strangely hypnotic, and made it hard to concentrate on all the other cool stuff [Ben] was up to.

If the topic of air bearings seems familiar, it might be because we recently reported on DIY air bearings made from used EDM electrodes. [Ben] saw that too, and dusted off his old air bearing project. Literally, as it turns out, because the graphite blocks whose porosity and softness make them the perfect material for air bearings also makes for a dusty workshop. We’d recommend breathing protection of some sort while machining graphite. In addition to simple puck bearings, [Ben] came up with more complicated designs, including the aforementioned spherical bearing. He used the steel ball itself as a precision tool to grind the graphite out, first by coating it with abrasive and then by cutting grooves in it to act like a file. A cylindrical bearing was also cut, this time with sandpaper glued directly to the ground steel rod that would seat in the bearing.

[Ben]’s other innovation is vacuum preloading, where he applies both vacuum and pressure to the bearing plenum. The vacuum provides the force needed to capture the moving element while the pressure bears the load. It’s a careful balancing act, but it works well enough to capture the large steel ball and keep it turning effortlessly.

We really liked [Ben]’s take on air bearings, especially his thoughts on creating fully enclosed cylindrical bearings. Those could be useful for low-friction linear drives, and we look forward to seeing more on those.

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Internal Power Pills

Arguably the biggest hurdle to implanted electronics is in the battery. A modern mobile phone can run for a day or two without a charge, but that only needs to fit into a pocket and were its battery to enter a dangerous state it can be quickly removed from the pocket. Implantable electronics are not so easy to toss on the floor. If the danger of explosion or poison isn’t enough, batteries for implantables and ingestibles are just too big.

Researchers at MIT are working on a new technology which could move the power source outside of the body and use a wireless power transfer system to energize things inside the body. RFID implants are already tried and tested, but they also seem to be the precursor to this technology. The new implants receive multiple signals from an array of antennas, but it is not until a couple of the antennas peak simultaneously that the device can harvest enough power to activate. With a handful of antennas all supplying power, this happens regularly enough to power a device 0.1m below the skin while the antenna array is 1m from the patient. Multiple implants can use those radio waves at the same time.

The limitations of these devices will become apparent, but they could be used for releasing drugs at prescribed times, sensing body chemistry, or giving signals to the body. At this point, just being able to get the devices to turn on so far under flesh is pretty amazing.

Recently, we asked what you thought of the future of implanted technology and the comment section of that article is a treasure trove of opinions. Maybe this changes your mind or solidifies your opinion.

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Mechanisms: Abrasives

In our “Mechanisms” series, we’ve featured the fascinating bits and pieces that go into making our mechanical world work. From simple machines such as screws and levers, from springs to couplings, and even more complex mechanisms like zippers and solenoids, we’ve covered the gamut. But we haven’t talked about one of the very earliest mechanisms, captured from nature by our clever ancestors to do useful work like grinding grain and shaping materials into tools: grit, sand, abrasives.

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Decellularization: Apples To Earlobes

Our bodies are not like LEGO blocks or computers because we cannot swap out our parts in the living room while watching television. Organ transplants and cosmetic surgery are currently our options for upgrades, repairs, and augments, but post-transplant therapy can be a lifelong commitment because of rejection. Elective surgery costs more than a NIB Millenium Falcon LEGO set. Laboratories have been improving the processes and associated treatments for decades but experimental labs and even home laboratories are getting in on the action as some creative minds take the stage. These folks aren’t performing surgeries, but they are expanding what is possible to for people to do and learn without a medical license.

One promising gateway to human building blocks is the decellularization and recellularization of organic material. Commercial scaffolds exist but they are expensive, so the average tinkerer isn’t going to be buying a few to play with over a holiday weekend.

Let’s explore what all this means. When something is decellularized, it means that the cells are removed, but the structure holding the cells in place remains. Recellularizing is the process where new cells are grown in that area. Decellularizing is like stripping a Hilton hotel down to the girders. The remaining structures are the ECM or the Extra Cellular Matrix, usually referred to as scaffolding. The structure has a shape but no functionality, like a stripped hotel. The scaffolding can be repopulated with new cells in the same way that our gutted hotel can be rebuilt as a factory, office building, or a hospital.

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