A fusion splicer being used to repair an optical fiber

Using A Fusion Splicer To Repair A Samsung TV’s Cable

May 23, 2022 by 31 Comments

Some Samsung TVs come with a system called One Connect, where all external cabling is connected to a separate box so that only one small signal cable goes to the TV. In some versions, the cable linking the TV with its Connect Box is a pure fiber optic cable that’s nearly transparent and therefore easy to hide.

Thin fiber optic cables are fragile however; when [Elecami Wolf] got one of these TVs for a very low price it turned out that this was because its One Connect cable had snapped. Replacement cables are quite expensive, so [Elecami Wolf] went on to investigate the inner workings of the fiber optic cable and figured out how to repair a broken one.

The cable consists of four pairs of plastic-coated glass fibers, which are attached to receivers and transmitters inside the thick connectors on either end. Repairing the cable required two things: figuring out which fibers should connect to each other, and a reliable way of connecting them together.

The first was difficult enough: a simple 1:1 connection didn’t work, so it took a bit of work to figure out the correct connection setup. One clever trick was pointing a camera at a working cable and comparing the flashing lights at each end; this helped to identify the right order for two of the four pairs. For the other two, a combination of reverse-engineering the electronic circuits and some systematic trial-and-error yielded a complete wiring diagram.

For the second part, [Elecami Wolf] called on a fiber optic expert who lent him a fusion splicer. This is a rather neat piece of equipment that semi-automatically brings two pieces of fiber together and welds them with an electric arc. Once this was complete, it was a matter of covering the splices to protect them from sharp bends, and the fancy TV was working again.

Although not everyone will have access to a multi-mode fusion splicer machine, [Elecami Wolf]’s videos provide fascinating insights into the workings of modern fiber-optic based consumer electronics. This might be the first fiber-optic splicing attempt we’ve seen; but if you’re trying to hook up an optical fiber to your circuit, this ball lens setup is a neat trick.

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One Coder Is Porting Portal To The Nintendo 64

May 18, 2022 by 10 Comments

When Portal came out in 2007, developers Valve chose not to release the groundbreaking title on an obsolete Nintendo console long out of production. Nobody cared at the time, of course, but [James Lambert] is here to right that wrong. Yes, he’s porting Portal to the N64.

The port, or “demake,” as [James] calls it, has been under construction for some time. The project has posed some challenges: Portal was developed for PCs that were vastly more powerful than the Nintendo 64 of 1996. Thus, initial concerns were that the console wouldn’t be able to handle the physics of the game or render the recursive portal graphics.

However, hard work has paid off. [James] has chipped away, bit by bit, making improvements to his engine all the while. The latest work has the portals rendering nicely, and the companion cube works just the way you’d expect. There’s also a visible portal gun, and the engine can even render 15 recursive layers when looking through mirrored portals. Sixteen was too much.

Of course, there’s still lots to do. There’s no player model yet, and basic animations and sound are lacking. However, the core concept is there, and watching [James] flit through the not-quite-round portals is an absolute delight. Even better, it runs smoothly even on original Nintendo hardware. It’s a feat worthy of commendation.

We had no idea what [James] had in store back when we featured his work creating real-time shadows on N64 hardware. Now we know! Video after the break.

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Bare-Metal STM32: Using The I2C Bus In Master-Transceiver Mode

May 11, 2022 by 34 Comments

As one of the most popular buses today for on- and inter-board communication within systems, there’s a good chance you’ll end up using it with an embedded system. I2C offers a variety of speeds while requiring only two wires (clock and data), which makes it significantly easier to handle than alternatives, such as SPI. Within the STM32 family of MCUs, you will find at least one I2C peripheral on each device.

As a shared, half-duplex medium, I2C uses a rather straightforward call-and-response design, where one device controls the clock, and other devices simply wait and listen until their fixed address is sent on the I2C bus. While configuring an STM32 I2C peripheral entails a few steps, it is quite painless to use afterwards, as we will see in this article. Continue reading “Bare-Metal STM32: Using The I2C Bus In Master-Transceiver Mode” →

The LED tree itself , filmed in the dark - a myriad of small orbs glowing mictures of green, blue and warm white

Kaleidoscope – Feelings Turned Into LED Tree

May 3, 2022 by 4 Comments

In 2020, [Eddie] found himself with a few hundred RGB LEDs left after a pandemic-interrupted project, and a slew of emotions he wanted to express – so he turned to the language of hardware, and started sculpting his feelings into an art project. He set out to build an LED tree around a piece of wood he picked for its cool shape, and trying out a long-shelved idea of his, while at it – using different resistors to mix colors of the RGB LEDs. The end result, pictured above, has earned “The Most Important Device” spot in our recent Sci-Fi contest, fair and square.

Initially, he wanted to use ATTiny microcontrollers and PWM all the lights in parallel. Having built an intermediate prototype, a small LED flower, he scrapped the idea due to technical problems, and then simplified it by hard-wiring RGB LEDs with randomly selected colors instead. As for the glowing orbs themselves, he made these just by pouring hot glue into silicon orb molds, a simple technique any of us could repeat. After 90 hours of work between him and an assistant he hired, the LEDs were wired up, each with random resistors connected to green and blue LED colors, and some warm white LEDs added into the mix.

He wanted to mostly use blue and green colors, as symbols of a world revived and revitalized – something we can’t help but keep our fingers crossed for. Before putting it all together, they wouldn’t know which colors each of the LEDs would power up in – part of the charm for this art piece, and no doubt a pleasant surprise. In the end, it turned out to be a futuristic decoration that we’re glad a camera could capture properly! If you like what you see, the build logs linked above have a bit more insights into how it all came together.

LED-adorned plants are fun projects that bring joy for a long time after you’ve finished them. You can easily make a LED tree out of what you have on hand, and if you get real fancy, you can create an intricate bonsai, too. And, if you’re ever interested to experiment with castellations, you can design yourself some PCB cube flowers!

This project was an entry into the 2022 Sci-Fi Contest. Check out all of the winning entries here.

A Universal, Non-planar Slicer For 3D Printing Is Worth Thinking About

April 23, 2022 by 28 Comments

One may think that when it comes to 3D printing, slicing software is pretty much a solved problem. Take a 3D model, slice it into flat layers equal to layer height, and make a toolpath so the nozzle can create those layers one at a time. However, as 3D printing becomes more complex and capable, this “flat planar slicing” approach will eventually become a limitation because a series of flat slices won’t necessarily the best way to treat all objects (nor all materials or toolheads, for that matter.)

How a 20 mm cube looks when sliced in a cone-shaped plane.

[René K. Müller] works to re-imagine slicing itself, and shows off the results of slicing 3D models using non-planar geometries. There are loads of pictures of a 20 mm cube being sliced with a variety of different geometries, so be sure to give it a look. There’s a video embedded below the page break that covers the main points.

It’s all forward-thinking stuff, and [René] certainly makes some compelling points in favor of a need for universal slicing; a system capable of handling any geometry, with the freedom to process along any path or direction. This is a concept that raises other interesting questions, too. For example, when slicing a 20 mm cube with non-planar geometries, the resulting slices often look strange. What’s the best way to create a toolpath for such a slice? After all, some slicing geometries are clearly better for the object, but can’t be accommodated by normal hot ends (that’s where a rotating, tilted nozzle comes in.)

Such worries may not be an issue for most users at the moment, but it’s worth trying to get ahead of the curve on something like this. And lest anyone think that non-planar slicing has no practical purpose, we previously covered [René]’s demonstration of how non-planar slicing can reliably create 90° overhangs with no supports.

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Watch A Complete Reflector Telescope Machined From A Single Block Of Glass

April 21, 2022 by 16 Comments

If this is the easy part of making a complete reflector telescope from a single piece of glass, we can’t wait to get a load of the hard part!

A little backstory may be in order for those who don’t follow [Jeroen Vleggaar]’s Huygens Optics channel on YouTube. A few months ago, he released a video discussing monolithic telescopes, where all the reflective and refractive surfaces are ground into a single thick block of glass. Fellow optical engineer [Rik ter Horst] had built a few tiny monolithic Schmidt-Cassegrain reflectors for use in cube sats, so [Jeroen] decided to build a scaled-up version himself.

The build starts with a 45 mm thick block of crown glass, from which a 50 mm cylinder is bored with a diamond hole saw. The faces of the blank are then ground into complex curves to reflect incoming light, first off the parabolic rear surface and then onto the hyperbolic secondary mirror ground into the center of the front face. A final passage through a refracting surface in the center of the rear face completes the photons’ journey through the block of glass, squeezing a 275 mm focal length into a compact package.

All this, of course, vastly understates the work required to pull it off. Between the calculations needed to figure out the surface shapes in the first place to the steps taken to machine a famously unforgiving material like glass, every step is fraught with peril. And because the design is monolithic, any mistakes mean starting all over again. Check out the video below and marvel at the skills needed to get results like this.

What strikes us most about [Jeroen]’s videos is the mix of high-tech and age-old methods and materials used in making optics, which we’ve seen him put to use to make everything from tiny Tesla valves to variable-surface mirrors.

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Turning Scrap Copper Into Beautiful Copper Acetate Crystals

April 20, 2022 by 37 Comments

Crystals, at least those hawked by new-age practitioners for their healing or restorative powers, will probably get a well-deserved eye roll from most of the folks around here. That said, there’s no denying that crystals do hold sway over us with the almost magical power of their beauty, as with these home-grown copper acetate crystals.

The recipe for these lovely giant crystals that [Chase Lean] shares is almost too simple — just scrap copper, vinegar, and a bit of hydrogen peroxide — and just the over-the-counter strength versions of those last two. The process begins with making a saturated solution of copper acetate by dissolving the scrap copper bits in the vinegar and peroxide for a couple of days. The solution is concentrated by evaporation until copper acetate crystals start to form. Suspend a seed crystal in the saturated solution, and patience will eventually reward you with a huge, shiny blue-black crystal. [Chase] also shares tips for growing crystal clusters, which have a beauty of their own, as do dehydrated copper acetate crystals, with their milky bluish appearance.

Is there any use for these crystals? Probably not, other than their beauty and the whole coolness factor of watching nature buck its own “no straight lines” rule. And you’ll no doubt remember [Chase]’s Zelda-esque potassium ferrioxalate crystals, or even when he turned common table salt into perfect crystal cubes.