Author: Al Williams

4351 Articles

Salty Refrigeration Is Friendly To The Environment

January 6, 2023 by 34 Comments

Widespread use of refrigerators is a hallmark of modern society, allowing people to store food and enjoy ice and cold beverages. However, a typical refrigerator uses gasses that are not always good for the environment. Now the Berkeley National Lab says they can change that using ioncaloric cooling, a new technique that uses salt as a refrigerant.

The new technique involves using ions to drive a solid-to-liquid phase change which is endothermic. Unlike some similar proposals, the resulting liquid material would be easy to pump through a heat exchanger. In simple terms, it is the same process as salting a road to change the melting point of ice. In this case, an iodine-sodium salt and an organic solvent combine. Passing current through the material moves ions which changes the material’s melting point. When it melts, it absorbs heat. When it resolidifies, it releases heat.

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Is It A Game? Or A Calculator?

January 6, 2023 by 27 Comments

If you are a certain age, you probably remember the Mattel Football game. No LCD screen or fancy cartridges. Just some LEDs and a way to play football when you should be in class. While these might seem primitive to today’s kids, they were marvels of technology in the 1970s when they came out. [Sean Riddle] looks, well, not exactly at the games, but more like in them. As it turns out, they used chips derived from those made for calculators.

[Sean’s] post is a glimpse into this world of over four decades past. Football was actually the second electronic game from Mattel. The first one was Auto Race. There were also games called Space Alert, Baseball, and Gravity. Inside each are quad in-line packages with 42 pins, a Rockwell logo, and a custom part number.

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PCB Gets Weighty Assignment

January 5, 2023 by 9 Comments

[Curious Scientist] tried building an integrated strain gauge on a PCB, but ran into problems. Mainly, the low resistance of the traces didn’t show enough change under strain to measure easily. Even placing a proper strain gauge on the PCB had limitations. His new design uses a bridge design to make the change in the gauges usefully large. You can see a video of the project below.

Bridging strain gauges isn’t a new idea. However, the novelty of this design is that the PCB has cantilever beams that facilitate the weighing. Standoffs mount a plate to the beams so that weight on the plate cause deformation on the beam that the strain gauges can measure.

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Excuse Me, Your Tie Is Unzipped

January 5, 2023 by 102 Comments

If you ask your typical handyperson what’s the one thing you need to fix most things, the answer might very well be duct tape. But second place — and first place in some circles — would have to be zip ties. These little wonders are everywhere if you look for them. But they are a relatively recent invention and haven’t always had the form they have today.

The original zip tie wasn’t called a zip tie or even a cable tie. In 1958 they were called Ty-Raps and produced by a company called Thomas and Betts. Originally meant to improve aircraft wiring harnesses, they found their way into various electronic equipment and packaging uses. But they’ve also become helpful in very unusual places too. A policeman trying to round up rioters would have problems carrying more than a few conventional handcuffs. But flexible cuffs based on zip ties are lightweight and easy to carry. Colon surgeons sometimes use a modified form of zip tie during procedures.

History

Maurus Logan worked for the Thomas and Betts company. In 1956, he was touring an aircraft manufacturing plant. Observing a wiring harness being put together on a nail board, similar to how car harnesses are made, he noted that the cables were bundled with waxed twine or nylon cord. A technician had to tie knots in the cord, sometimes cutting their fingers and often developing calluses. In addition, the twine was prone to fungal growth, requiring special treatment.

Logan kept turning the problem over in his mind and tried various approaches. By 1958, he had a patent for the Ty-Rap. The tie was lightweight, easy to install, easy to remove, and inexpensive.

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Stewart Platform Keeps Its Eye On The Ball

January 4, 2023 by 4 Comments

Although billed as a balancing robot, [Aaed Musa’s] robot doesn’t balance itself. It balances a ball on a platform. You might recognize this as something called a Stewart platform, and they are great fun at parties if you happen to party with a bunch of automation-loving hackers, that is. Take a look at the video below to see the device in action.

If you want to duplicate the project, there’s a bit of expense, but the idea behind it is explained in the video. Much of the robot is 3D printed with threaded inserts. Even the ball is 3D printed in two parts along with a cubic connector to hold the two hemispheres together. The acrylic platform was cut with a water jet, although you could just as easily have cut it with hand tools.

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Something’s Rotating In The State Of Denmark: A Clock

January 4, 2023 by 15 Comments

If you visit the Copenhagen City Hall, you’ll see an ornate mechanical clock. By itself, this is unremarkable, of course. There are plenty of ornate clocks in city halls around the world, but this one has a fascinating backstory that starts with a locksmith named Jan Jens Olsen. Unfortunately, Jens didn’t actually complete the clock before his death. It would take 12 years to put together the 15,448 individual parts. However, he did manage to see most of the clock that he had been designing for 50 years put together.

Jens was 60 when he started constructing the clock, but the story starts when he was only 25. In Strasbourg, the young locksmith saw an astronomical clock with a perpetual calendar in a cathedral. He was fascinated and returned several times to study the mechanism. Around the age of 30, Jens had moved to watchmaking and had a keen interest in astronomy — he was a founding member of the Danish Astronomical Society. Perhaps it was the combination of these two interests that made it inevitable that he would want to build a precise astronomically-correct clock.

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A Homebrew SMD Vise Built From Scrap Wood

January 4, 2023 by 23 Comments

We don’t see too many wooden projects around these parts, but when [olikraus] turned a few pieces of scrap lumber into a functional SMD vise, how could we not take notice? The idea is simple. Two pieces of wood with slots in them hold the PCB. Two other pieces form an arm with an adjustable needle that can hold down tiny parts while you solder. Magnets hold each piece to a metal working surface. Simple and elegant.

We might have 3D printed some of the pieces, but then again, you have to be careful where your soldering iron goes if you go that route. The other advantage to using wood is that you can easily grab a few pieces of scrap and have a different-sized vice in just a few minutes.

There are a few improvements we might suggest. For example, a thumbscrew to fix the needle would be welcome. It seems like you could make the part that holds the needle smaller, too, to help you get your soldering iron into the same area. But it looks workable with no changes at all.

Working with scrap wood isn’t glamorous, but it does make for quick and easy functional builds. A number of the holes and bolts here could even be replaced with glue if you don’t mind the time for it to set.

Of course, you could mix and match this with other designs. We like the “dollar store PCB holder,” but it would work well with the arm from this project. We couldn’t help but think of the SMD beak when we saw this project.