Author: Al Williams

4457 Articles

Printing With Glass Fiber Filament

December 10, 2023 by 12 Comments

[ModBot] has been trying different engineering plastics for 3D printing. He recently looked at carbon fiber mixed with PET, but this time, he shows us his results with PET with glass fiber, or PET-GF. You can see how it all turned out in the video below.

The first part of the video compares the specifications, and, as you might expect, some factors are better for carbon fiber, and others are better for glass fibers. Once he gets to the printing, he covers the high temperatures needed (280-320C). He also talks about how either fiber will chew up nozzles and extruders.

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Clockhands For Faster CPU Execution

December 9, 2023 by 15 Comments

When you design your first homebrew CPU, you probably are happy if it works and you don’t worry as much about performance. But, eventually, you’ll start trying to think about how to make things run faster. For a single CPU, the standard strategy is to execute multiple instructions at the same time. This is feasible because you can do different parts of the instructions at the same time. But like most solutions, this one comes with a new set of problems. Japanese researchers are proposing a novel way to work around some of those problems in a recent paper about a technique they call Clockhands.

Suppose you have a set of instructions like this:

LOAD A, 10
LOAD B, 20
SUB A,B
LOAD B, 30
JMPZ  DONE
INC B

If you do these one at a time, you have no problem. But if you try to execute them all together, there are a variety of problems. First, the subtract has to wait for A and B to have the proper values in them. Also, the INC B may or may not execute, and unless we know the values of A and B ahead of time (which, of course, we do here), we can’t tell until run time. But the biggest problem is the subtract has to use B before B contains 30, and the increment has to use it afterward. If everything is running together, it can be hard to keep straight.

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Nanobots Self Replicate

December 9, 2023 by 11 Comments

Hey, what if you could have a factory that makes robots that is run by… robots? This is hardly an original thought, but we are a long way from having an assembly line of C3POs self-replicating. On the other hand, animals — including humans — self-replicate all the time using DNA. Now, scientists are making tiny nanorobots from DNA that can assemble more DNA, including copies of themselves.

Assembling 3D structures with DNA has deep implications. For example, it might be possible to build drugs in situ, delivering powerful toxins only to cancer cells. Another example would be putting DNA factories in diabetes patients to manufacture the insulin they can’t.

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Marconi Circuit Magnification Meter Gives Up Secrets

December 9, 2023 by 5 Comments

[Thomas] picked up a Marconi TF1245 with dents and dings. We have to admit that we had not heard of a “circuit magnification meter,” but apparently, this was a thing in the late 1960s and early 1970s. Turns out, we have heard of this kind of meter before, but it was called a Q meter. The device works using a very low-impedance resonant circuit and a very high-impedance voltmeter. It measures the ratio of the voltage across the known circuit and the unknown circuit. This particular meter needs an external signal source with very special characteristics. You can see the well-built device in the video below.

The unit didn’t seem to work, but we suspect that it didn’t like his normal signal source. According to a comment in the manual, the matching signal generator delivered 0.5V into a 0.5 ohm load. You could also use a matching transformer to get to the required match.

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MOSFETs — The Hidden Gate

December 8, 2023 by 12 Comments

How many terminals does a MOSFET have? Trick question since most have three leads, even though there are really four connections to the underlying device. It isn’t a conspiracy, though and [Aaron Lanterman] talks about how MOSFETs really work and why thinking of them as three-terminal devices can lead you astray in a recent video that you can watch below.

Like many people, [Aaron] points out the parallel between a triode vacuum tube and a MOSFET. That’s not surprising, since a solid-state tube was exactly what they were looking for when they developed the FET. Since tubes and FETs are both voltage controllers, it is easy to think of the gate as the grid, the source as the cathode, and the drain as the plate. But, [Aaron] shows this isn’t really a very accurate picture.

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Fail Of The Week: [Mark] Makes An Atari Cartridge

December 7, 2023 by 8 Comments

Part of the magic of the movies is that the actors always know what will happen next. There never has to be a scene where James Bond orders wine, and the sommelier has to correct his pronunciation, or he miscounts his hand at baccarat. Real life is rarely as smooth. Of course, YouTube is more akin to a movie than real life, and we always wonder how many flawlessly executed projects you see on YouTube really went that well. [Mark Fixes Stuff] left no scenes on the cutting room floor, though, in his realistic portrayal of his quest to build a nice-looking Atairi 2600 cartridge. Watch it below.

Spoiler alert: In the end, it all worked out. But getting there was a series of misadventures. Starting out with [Parker Dillman’s] PCB, he put together the insides of the cartridge, including a socket for the EPROM. He then resin-printed a case. Like many of our own projects, the first run wasn’t quite the size he expected. It was probably close enough, though, but then he realized the socket made the board too tall to fit in the enclosure.

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BASIC In Your Browser

December 7, 2023 by 31 Comments

If you are a certain age or just like retrocomputers, you probably have a soft spot for good old-fashioned BASIC. If you miss those days but don’t want to install a modern interpreter, you don’t have to. Just load a web page containing the “BASIC Anywhere Machine” from [CJ Veniot]. Worried about it being “in the cloud?” It isn’t? It runs in your browser, and if you are a TiddlyWiki fan, it will even live inside your Wiki, which you can host as you please.

The project has lots of features, including some integration back into TiddlyWiki, which we haven’t tried. But you can use graphics commands, work with the mouse, and do other fun things.

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