Author: Al Williams

4349 Articles

Microscopic Metal 3D Printing With Gels

December 7, 2022 by 3 Comments

Everyone wants to 3D print with metals, but it is a difficult task. You need high temperatures and metals with high thermal conductivity make the problem even worse. Researchers at Caltech have a way of printing tiny metal structures. The trick? They don’t print metals at all. Instead, they 3D print a hydrogel and then use it as a scaffold to form metallic structures. You can read the full paper, if you are interested in the details.

Hydrogels are insoluble in water and made from flexible polymer chains. If you’ve ever handled a soft contact lens, that’s a hydrogel. Like resin printing, UV light triggers chemical reactions in the hydrogels, causing them to harden in the desired pattern.

What about the metal? They infuse the hydrogel with a metallic salt dissolved in water.  This saturates the hydrogel. Burning in a furnace causes the hydrogel to burn away but leaves the metal. The furnace also causes the structure to shrink, so this is a good method for very tiny pieces. The team has made prints with feature sizes around 40 microns.

By altering the metal salts, you can work with different metals or even mix different metals. The team has produced parts using copper, nickel, silver, and several alloys.

Printing small structures is a big research goal with many different approaches. We’ve even seen a tiny welder.

The 10 Kinds Of Programmers That Use Calcutron-33

December 7, 2022 by 18 Comments

It is interesting how, if you observe long enough, things tend to be cyclical. Back in the old days, some computers didn’t use binary, they used decimal. This was especially true of made up educational computers like TUTAC or CARDIAC, but there was real decimal hardware out there, too. Then everyone decided that binary made much more sense and now it’s very hard to find a computer that doesn’t use it.

But [Erik] has written a simulator, assembler, and debugger for Calcutron-33, a “decimal RISC” CPU. Why? The idea is to provide a teaching platform to explain assembly language concepts to people who might stumble on binary numbers. Once they understand Calcutron, they can move on to more conventional CPUs with some measure of confidence.

To that end, there are several articles covering the basic architecture, the instruction set, and how to write assembly for the machine. The CPU has much in common with modern microprocessors other than the use of decimal throughout.

There have been several versions of the virtual machine with various improvements and bug fixes. We’ll be honest: we admire the work and its scope. However, if you already know about binary, this might not be your best bet. What’s more is, maybe you should understand binary before tackling assembly language programming, at least in modern times. Still, it does cover a lot of ground that applies regardless.

Made-up computers like TUTAC and CARDIAC were all the rage when computer time was too expensive to waste on mere students. There was also MIX from computer legend Donald Knuth.

In My Neighborhood, We Played Asteroids…with Real Asteroids

December 7, 2022 by 12 Comments

There was a comedian in the 1980s who always said he grew up in a tough neighborhood. He claimed they played cops and robbers with real cops. They played gin rummy with real gin. Well, maybe if he knew about [Neal Agarwal]’s asteroid launcher simulation website, he would have said they played asteroids with real asteroids.

If you ever wondered what would happen if a 1,500-foot stone or iron asteroid hit your hometown going at 38,000 mph, now you can find out.  Apparently, I live far enough in the suburbs that even a 1 mile-wide iron asteroid hitting the center of Houston wouldn’t put a crater under my house. The 17-mile-wide and 2,608-foot-deep crater would release the equivalent of 399 Gigatons of TNT, but it wouldn’t reach me.

The 29-mile-wide fireball would be a different story. Oh, and the 244 dB shockwave would almost certainly reach me. So if the clothes catching on fire resulting in second- and third-degree burns didn’t get me, perhaps the shockwave would. The simulation says that zone will have 99% fatalities, and even further out, people will get severe lung damage. Eardrums burst even further away. Homes would collapse almost to the Mexican border.

The 1,000-mile-per-hour wind might present problems, too. While we are well-situated for hurricanes in this area, that’s about five times more wind than even a big hurricane generates. And we are not well prepared for earthquakes, much less the magnitude 70 quake that would occur.

Pretty bleak. On the plus side, a strike like that happens about once every 2.6 million years. If you try it yourself, be sure to scroll down the right panel to see the graphical representation of the different effects.

Maybe NASA is on to something when they tell us they want to learn to deflect asteroids. Even private foundations are getting into the business of finding them.

Merry Christmas! Rip And Tear!

December 7, 2022 by 6 Comments

If you want a little mayhem on your Christmas tree, you can check out [Sprite_tm]’s tiny PC Christmas ornament. With 3D printing, that isn’t such a tall order, but [Sprite]’s does have a unique ability: it plays DOOM, as you can see in the video below.

The device uses an ESP32, and while [Sprite] had ported the iconic shooter to the microcontroller before, he decided to use a Game Boy port that is more lightweight instead. There were a few reasons for the choice, including the ability to do Bluetooth so you could connect controllers so you can play the game. The only catch was he had to pull off the flash memory and replace it with a larger one (see the second video below).

Granted, the screen is tiny, so it is sort of a novelty. But if you want to have a go, the files are all there. As you might expect, there is a tiny battery and the circuitry required to recharge it, as well. We’d probably make an adapter to let it charge from the Christmas lights, but that can wait for version 2.

The input device handling is a bit strange. Bluetooth BLE devices will automatically grab an input device that is in pairing mode. There is no provision for connecting using the “normal” Bluetooth mechanism. A fun project and you could use the case for some other tiny projects, too. A larger flash on an ESP32 has lots of possibilities, as well.

If you need a primer on the ESP32, we got it. If you want to play DOOM on something truly strange, try seven-segment displays.

Continue reading “Merry Christmas! Rip And Tear!” →

PSA: Watch Out For White Filament

December 6, 2022 by 48 Comments

We all know that using 3D printing filament with exotic filament that has metal or carbon fibers in it will tend to wear standard nozzles. That’s why many people who work with filaments like that use something other than conventional brass nozzles like hardened steel. There are even nozzles that have a ruby or diamond surfaces to prevent wear. However, [Slant 3D] asserts something we didn’t know: white filament may be wearing your nozzle, too. You can see his argument in the video below.

The reason? According to Slant 3D, the problem is the colorant added to make it white: titanium dioxide. Unlike some colorants, the titanium dioxide colorant has a large grain size. The video claims that the hard titanium material has a particle size of about 200 nm, which is much larger than, say, carbon black, which is about 20 times smaller.

Continue reading “PSA: Watch Out For White Filament” →

The World’s Brightest Laser Pointer?

December 6, 2022 by 37 Comments

The videos from [styropyro] are always amusing and informative. However, ironically for him, he is alarmed that many green laser pointers are more powerful than they are supposed to be. Sure, you often want a powerful laser, but if you think a laser is safe and it isn’t, you could… well… put an eye out. See the video below to see what [styropyro] claims is the brightest laser pointer in the world.

The key is a possibly gray market very large green laser array. It appears to have at least 24 lasers and some pretty serious lenses. He tested the array first with a power supply and it looked like something out of a bad science fiction movie, even at reduced power.

Continue reading “The World’s Brightest Laser Pointer?” →

Gift Idea From 1969: A Kitchen Computer

December 6, 2022 by 51 Comments

The end of the year is often a time for people to exchange presents and — of course — the rich want to buy each other the best presents. The Neiman Marcus company was famous for having a catalog of gift ideas. Many were what you’d consider normal gifts, but there were usually extreme ones, like a tank trunk filled with 100,000 gallons of cologne. One year, the strange gift was an authentic Chinese junk complete with sails and teak decks. They apparently sold three at $11,500 (in 1962 money, no less). Over the top? In 1969, they featured a kitchen computer.

Wait a minute! In 1969, computers were the purview of big companies, universities, and NASA, right? Well, not really. By that time, some industrial minicomputers were not millions of dollars but were still many thousands of dollars. The price in the catalog for the kitchen computer was $10,600. That’s about $86,000 in today’s money. The actual machine was a Honeywell 316, based on one of the computers that helped run the early Internet.

Continue reading “Gift Idea From 1969: A Kitchen Computer” →