Open-Source Method Makes Possible Two-Layer PCBs With Through-Plating At Home

June 11, 2021 by Dan Maloney 39 Comments

If the last year and its supply chain problems have taught us anything, it’s the value of having a Plan B, even for something as commoditized as PCB manufacturing has become. If you’re not able to get a PCB made commercially, you might have to make one yourself, and being able to DIY a dual-layer board with plated-through vias might just be a survival skill worth learning.

Granted, [Hydrogen Time]’s open-source method, which he calls “Process 01”, is something that he has been working on for years now. And it’s quite the feat of chemistry, which may require you to climb a steep learning curve, depending on how neglected the skills from high school or college chemistry are. But for as complex as Process 01 is, it’s actually pretty straightforward, and the first video below covers it in extreme detail. It starts with a drilled double-sided copper-clad board, which after cleaning is given a bath in palladium chloride. A follow-up dunk in stannous chloride leaves a thin film of palladium metal over all surfaces, even the via walls. This then acts as a catalyst for electroless copper plating in a solution of copper sulfate, followed by an actual electroplating step to thicken the copper plating.

After more washing, photoresist is applied to define the traces as well as to protect the now-plated vias, the board is etched, and a solder mask layer is applied. The boards might not be mistaken for commercial PCBs, but they’re pretty darn good, and as [Hydrogen Time] states, Process 01 is only a beginning. We expect this will be improved and streamlined as time goes by.

Fair warning, though — some steps require a fume hood to be performed safely. Luckily, we’ve got that covered. Sort of.

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Injection-Molded Glass Breakthrough Shatters Ceiling Of Work Methods

June 10, 2021 by Kristina Panos 36 Comments

Glass is one of humanity’s oldest materials, and it is still used widely for everything from drinking vessels and packaging to optics and communications. Unfortunately, the methods for working with glass are stuck in the past. Most methods require a lot of high heat in the range of 1500 °C to 2000 °C, and they’re all limited in the complexity of shapes that can be made.

As far as making shapes goes, glass can be blown and molten glass pressed into molds. Glass can also be ground, etched, or cast in a kiln. Glass would be fantastic for many applications if it weren’t for the whole limited geometry thing. Because of the limitations of forming glass, some optic lenses are made with polymers, even though glass has better optical characteristics.

Ideally, glass could be injection molded like plastic. The benefits of this would be twofold: more intricate shapes would be possible, and they would have a much faster manufacturing time. Well, the wait is over. Researchers at Germany’s University of Freiburg have figured out a way to apply injection molding to glass. And it’s not just any glass — they’ve made highly-quality, transparent fused quartz glass, and they did it at lower temperatures than traditional methods. The team used x-ray diffraction to verify that the glass is amorphous and free of crystals, and were able to confirm its optical transparency three ways — light microscopy, UV-visible, and infrared measurements. All it revealed was a tiny bit of dust, which is to be expected outside of a clean room.

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Trials Begin For Lozenge That Rebuilds Tooth Enamel

June 2, 2021 by Kristina Panos 48 Comments

For all the cool regenerative tricks the human body can do, it’s kind of weird that we only have one shot at tooth enamel with no way to get it back. That may be about to change, as researchers at the University of Washington have developed a lozenge that rebuilds this precious protective coating a few microns at a time and are taking it to the trial stage. Could it really work? It’s certainly something to chew on.

The lozenge uses a genetically-engineered peptide (a chain of amino acids) derived from a protein that’s involved in developing enamel in the first place, as well as with the formation of the root surface of teeth. Inside the lozenge, this peptide works alongside phosphorus and calcium ions, which are the building blocks of tooth enamel. It’s designed to bind to damaged enamel without harming the gums, tongue, or other soft tissues of the mouth.

The researchers have already verified the efficacy on teeth extracted from humans, pigs, and rats, so the trials will largely revolve around comparing it to other whitening methods and documenting their findings.

One added advantage is that the new enamel the lozenges produce is really white, because it’s brand new. These lozenges sound like an all-around great solution, especially compared with traditional whitening techniques that often make enamel weaker. The researchers are also developing an over-the-counter toothpaste and some kind of solution for hypersensitivity, which is right up our alley.

We are skeptical of course, because nothing in history thus far has been able to regenerate enamel. Then again, yours truly uses toothpaste with nano-hydroxyapatite, which is touted as a non-toxic version of the same mineral that makes up teeth and bones. Skepticism abounds with that stuff, too, although my grill looks better to me. But why settle for new enamel when you could regrow entire teeth?

Main image by Eric Moreau and thumbnail image by Kevin Bation via Unsplash

Thin Coatings Require An Impressive Collection Of Equipment And Know-How

May 31, 2021 by Dan Maloney 15 Comments

Let’s be honest — not too many of us have a need to deposit nanometer-thick films onto substrates in a controlled manner. But if you do find yourself in such a situation, you could do worse than following [Jeroen Vleggaar]’s lead as he builds out a physical vapor deposition apparatus to do just that.

Thankfully, [Jeroen] has particular expertise in this area, and is willing to share it. PVD is used to apply an exceedingly thin layer of metal or organic material to a substrate — think lens coatings or mirror silvering, as well as semiconductor manufacturing. The method involves heating the coating material in a vacuum such that it vaporizes and accumulates on a substrate in a controlled fashion. Sounds simple, but the equipment and know-how needed to actually accomplish it are daunting. [Jeroen]’s shopping list included high-current power supplies to heat the coating material, turbomolecular pumps to evacuate the coating chamber, and instruments to monitor the conditions inside the chamber. Most of the chamber itself was homemade, a gutsy move for a novice TIG welder. Highlights from the build are in the video below, which also shows the PVD setup coating a glass disc with a thin layer of silver.

This build is chock full of nice details; we especially liked the technique of monitoring deposition progress by measuring the frequency change of an oscillator connected to a crystal inside the chamber as it accumulates costing material. We’re not sure where [Jeroen] is going with this, but we suspect it has something to do with some hints he dropped while talking about his experiments with optical logic gates. We’re looking forward to seeing if that’s true.

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Cocktail Of Chemicals Makes This Blueprint Camera Unique

May 24, 2021 by Dan Maloney 18 Comments

When you’re looking at blueprints today, chances are pretty good that what you’re seeing is anything but blue. Most building plans, diagrams of civil engineering projects, and even design documents for consumer products never even make it to paper, let alone get rendered in old-fashioned blue-and-white like large-format prints used to produced. And we think that’s a bit of a shame.

Luckily, [Brian Haidet] longs for those days as well, so much so that he built this large-format cyanotype camera to create photographs the old-fashioned way. Naturally, this is one of those projects where expectations must be properly scaled before starting; after all, there’s a reason we don’t go around taking pictures with paper soaked in a brew of toxic chemicals. Undaunted by the chemistry, [Brian] began his journey with simple contact prints, with Sharpie-marked transparency film masking the photosensitive paper, made from potassium ferricyanide, ammonium dichromate, and ammonium iron (III) oxalate, from the UV rays of the sun. The reaction creates the deep, rich pigment Prussian Blue, contrasting nicely with the white paper once the unexposed solution is washed away.

[Brian] wanted to go beyond simple contact prints, though, and the ridiculously large camera seen in the video below is the result. It’s just a more-or-less-lightproof box with a lens on one end and a sheet of sensitized paper at the other. The effective ISO of the “film” is incredibly slow, leading to problematically long exposure times. Coupled with the distortion caused by the lens, the images are — well, let’s just say unique. They’ve got a ghostly quality for sure, and there’s a lot to be said for that Prussian Blue color.

We’ve seen cyanotype chemistry used with UV lasers before, and large-format cameras using the collodion process. And we wonder if [Brian]’s long-exposure process might be better suited to solargraphy.

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Coffee Cupping Is A Grind — Spectroscopy Could Brew Better Beans

May 1, 2021 by Kristina Panos 18 Comments

If you’ve ever bought whole coffee beans, chances are good that there was all kinds of information on the bag that led to your decision, like the origin, the roast type, and the flavor notes. Traditionally, coffee grading — that’s judging the aroma of both dry and wet grounds and slurping the coffee evenly across the tongue to determine the flavor profile — is done by humans in a process called cupping. To call it a process is too clinical — it’s really more like a ceremony performed with the grave sincerity that coffee deserves.

A traditional cupping ceremony. Image via Kaldi’s Coffee

There’s an industry standard coffee flavor wheel, so why not leverage that to make a robot that can remove the human bias and possible error of doing things the traditional way? That’s exactly what Demetria, a Columbian-Israeli company is doing.

They’ve developed an AI platform that can determine bean quality as judged by handheld scanners that were born on Kickstarter. The scanner uses near-infrared to look for biochemical markers in the bean, which it uses to match up with a profile backed by the all-knowing coffee flavor wheel.

Demetria is using SCiO scanners and a custom app to judge beans before they’re even roasted, which greatly speeds up the process but makes us wonder how green bean spectroscopy stacks up against roasted beans as judged by humans. You may remember the SCiO, a pocket-sized, connected spectrometer made by Consumer Physics that finally started delivering the goods a few years after funding. If you got your hands on a SCiO, you might like to know that there’s an open project out there to hack them. Sparkfun did a nice, thorough teardown, and it seems to be a well-engineered piece of hardware.

On the one hand, cupping is a tradition and thus may people feel that robbing coffee of this tradition will rob coffee of its soul. On the other hand, cupping is wasteful, as the coffee must be roasted and ground immediately prior to the ceremony and it requires the availability of Q graders who have been trained in the ways of coffee grading.

Want to know more about coffee production? Might as well learn the Retrotechtacular way.

[Main and thumbnail images via Demetria]

Electric Vehicle 1900’s Style: New Leases On Old Tech

April 8, 2021 by Al Williams 69 Comments

Excited about your new electric vehicle? Thomas Edison would be, too. He tried to produce electric vehicles for Ford around 1900. Petroleum-based vehicles dashed his dreams of the electric car, and the battery he wanted to use languished as a technological dead end. The batteries were long-lasting, sure, but they were expensive and had other problems, not the least of which was producing hydrogen gas. But that battery technology is receiving renewed interest today, because some of the things that made it a bad car battery make it good for alternate energy projects.

You wouldn’t think a century-old battery technology that was never very popular would make a comeback. But then again, who thought we’d see the return of bell-bottom pants or vinyl records? Continue reading “Electric Vehicle 1900’s Style: New Leases On Old Tech” →