Using FreeCAD To Replace OEM Parts

June 10, 2023 by Bryan Cockfield 46 Comments

As much as we might all like it if manufacturers supported their products indefinitely with software updates or replacement parts, this just isn’t feasible. Companies fail or get traded, technologies evolve, and there’s also an economic argument against creating parts for things that are extremely old or weren’t popular in the first place. So, for something like restoring an old car, you might have to resort to fabricating replacement parts for your build on your own. [MangoJelly] shows us how to build our own replacement parts in FreeCAD in this series of videos.

The build does assume that the original drawings or specifications for the part are still available, but with those in hand FreeCAD is capable of importing them and then the model scaling to match the original specs shown. This video goes about recreating a hinge on an old truck, so with the drawings in hand the part is essentially traced out using the software, eventually expanding it into all three dimensions using all of the tools available in FreeCAD. One of the keys to FreeCAD is the various workbenches available that all have their own sets of tools, and being able to navigate between them is key to a build like this.

FreeCAD itself is an excellent tool for anyone repairing old vehicles like this or those making 3D prints, designing floorplans for houses, or really anything you might need to model in a computer before bringing the idea into reality. It does have a steep learning curve (not unlike other CAD software) so it helps to have a video series like this if you’re only just getting started or looking to further hone your design skills, but the fact that it’s free and open-source make it extremely attractive compared to its competitors.

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What Do You Want In A Programming Assistant?

June 10, 2023 by Al Williams 57 Comments

The Propellerheads released a song in 1998 entitled “History Repeating.” If you don’t know it, the lyrics include: “They say the next big thing is here. That the revolution’s near. But to me, it seems quite clear. That it’s all just a little bit of history repeating.” The next big thing today seems to be the AI chatbots. We’ve heard every opinion from the “revolutionize everything” to “destroy everything” camp. But, really, isn’t it a bit of history repeating itself? We get new tech. Some oversell it. Some fear it. Then, in the end, it becomes part of the ordinary landscape and seems unremarkable in the light of the new next big thing. Dynamite, the steam engine, cars, TV, and the Internet were all predicted to “ruin everything” at some point in the past.

History really does repeat itself. After all, when X-rays were discovered, they were claimed to cure pneumonia and other infections, along with other miracle cures. Those didn’t pan out, but we still use them for things they are good at. Calculators were going to ruin math classes. There are plenty of other examples.

This came to mind because a recent post from ACM has the contrary view that chatbots aren’t able to help real programmers. We’ve also seen that — maybe — it can, in limited ways. We suspect it is like getting a new larger monitor. At first, it seems huge. But in a week, it is just the normal monitor, and your old one — which had been perfectly adequate — seems tiny.

But we think there’s a larger point here. Maybe the chatbots will help programmers. Maybe they won’t. But clearly, programmers want some kind of help. We just aren’t sure what kind of help it is. Do we really want CoPilot to write our code for us? Do we want to ask Bard or ChatGPT/Bing what is the best way to balance a B-tree? Asking AI to do static code analysis seems to work pretty well.

So maybe your path to fame and maybe even riches is to figure out — AI-based or not — what people actually want in an automated programming assistant and build that. The home computer idea languished until someone figured out what people wanted to do with them. Video cassette didn’t make it into the home until companies figured out what people wanted most to watch on them.

How much and what kind of help do you want when you program? Or design a circuit or PCB? Or even a 3D model? Maybe AI isn’t going to take your job; it will just make it easier. We doubt, though, that it can much improve on Dame Shirley Bassey’s history lesson.

3D Printing LEGO-like Blocks

June 10, 2023 by Bryan Cockfield 8 Comments

LEGO are perhaps the perfect children’s toy, at least until you step on the errant brick while walking around the house. Available in all kinds of sets with varying themes and characters, they encourage building and creativity in kids like no other. Those with 3D printers might have considered creating their own specialty blocks, but the manufacturing of real LEGO blocks involves steel molds with extremely tight tolerances far outside the realm of most 3D printers. To print blocks capable of interconnecting in a similar way involves taking advantage of the characteristics of 3D printers and their materials instead, as [CNC Kitchen] demonstrates with these PrintABloks.

The PrintABlok was the idea of [Joe Larson] aka [3D Printing Professor] and is built around a one-unit base block, which has holes on all of its sides, paired with small connecting pieces which are placed in the holes to connect the various blocks to one another. Using your CAD software of choice (although they were originally built using Blender), the base block can be lengthened or widened for printing various different types of blocks, and the diamond-shaped hole can even be added to various prints that aren’t blocks at all. This means that a wide variety of parts can be made, all designed to interlock with the bricks or various other shapes. [Joe] even created an array of themed sets like robots, castles, and dinosaurs and although he sells these more complex models, he released his base set and interconnection mechanism for free and is available for anyone to use.

Another perk of the PrintABlok system is that they are scalable, mitigating safety risks for smaller children that might try to swallow some of the smaller parts. It’s an excellent way to put the 3D printer to work if there are any children around in the house. But this isn’t the only LEGO-inspired build we’ve ever seen, and they aren’t always going to be used to make children’s toys. [Ivan] recently used similar 3D-printed interlocking bricks more in the style of LEGO Technic to attempt to build a human-rideable go-kart.

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Processing of PP/MWCNT nanocomposites and coating them with plasmonic NPs. (Credit: Sara Fateixa et al., 2023)

Affordably Detecting Water Pollutants Using 3D Printed Lattices And Plasmonic Nanoparticles

June 10, 2023 by Maya Posch 6 Comments

Although detecting pollution in surface waters has become significantly easier over the years, testing for specific pollutants still requires the taking of samples that are then sent to a laboratory for analysis. For something like detecting pesticide run-off, this can be a cumbersome and expensive procedure. But a 3D printed sensor demonstrated by [Sara Fateixa] and international colleagues offers hope that such tests can soon be performed in the field. The most expensive part of this setup is the portable Raman spectrometer that is used to detect the adsorbed molecules on the printed test strips.

The printed structure itself forms a plasmonic structure with gold or silver as the plasmonic metals deposited on the polypropylene (PP) and multi-walled carbon nanotube (MWCNT, 4% by weight) material. The mixture of PP and MWCNTs is to use both the bio-compatible properties of the former, while using the latter to make the PP significantly easier to print with and enhancing its mechanical properties.

Hamamatsu Raman Spectroscopy SERS Detection Module C13560.

For the experiment, researchers used a few prepared sensors to detect herbicides, including paraquat. This herbicide is cheap, widely used, and banned in various countries. After dissolving it in low concentrations in both tap water and sea water, a 3D printed sensor with Ag coating was was exposed to each sample before being left to dry at room temperature. Afterwards a Hamamatsu C13560 portable Raman spectrometer was used to analyze the sensors using surface-enhanced Raman scattering (SERS). The combination of plasmonic structures and Raman scattering means a significantly enhanced sensitivity, on the order of singular molecules, and is what makes SERS such a useful analytical technique.

In the resulting scan results, the herbicides showed up clearly, and further long-duration testing of newly printed sensors showed them to be very stable, even after 150 days of being stored. This makes it a promising new way to affordably and quickly perform tests for pollution, requiring only minimal local infrastructure to produce and analyze the sensors.

Heading: Processing of PP/MWCNT nanocomposites and coating them with plasmonic NPs. (Credit: Sara Fateixa et al., 2023)

Magnetic Bubble Memory Brought To Life On Heathkit

June 9, 2023 by Bryan Cockfield 11 Comments

There are all kinds of technology that appear through the ages that find immediate success, promise to revolutionize the world, but fade to obscurity almost as quickly. Things like the ZIP disk, RDRAM, the digital compact cassette, or even Nintendo’s VirtualBoy. Going even further back in time [smbaker] is taking a look a bubble memory, a technology that was so fast and cost-effective for its time that it could have been used as “universal” memory, combining storage and random-access memory into a single unit, but eventually other technological developments overshadowed its quirks.

[smbaker] is placing his magnetic bubble memory module to work in a Heathkit H8, an Intel 8080-based microcomputer from the the late 70s. The video goes into great detail on the theory of how these devices used moving “bubbles” of magnetism to store information and how these specific devices work before demonstrating the design and construction of a dedicated support card which hosts the module itself along with all of the necessary circuitry to allow it to communicate with the computer. From there he demonstrates booting the device using the bubble memory and performs several write and read actions using the module as a demonstration.

Eventually other technologies such as solid-state RAM and various hard disk drives caused the obsolescence of this technology, but it did hang on for a bit longer in industrial settings due to its ability to handle high vibrations and mechanical shocks, mostly thanks to the fact that they had no moving parts. Eventually things like Flash memory came around to put the final nail in the coffin for these types of memory modules, though. The Heathkit H8 is still a popular computer for retrocomputing enthusiasts nonetheless, and we’ve seen all kinds of different memory modules put to work in computers like these.

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NASA Team Sets New Space-to-Ground Laser Communication Record

June 9, 2023 by Joseph Long 13 Comments

[NASA] and a team of partners has demonstrated a space-to-ground laser communication system operating at a record breaking 200 gigabit per second (Gbps) data rate. The TeraByte InfraRed Delivery (TBIRD) satellite payload was designed and built by [MIT Lincoln Laboratory]. The record of the highest data rate ever achieved by a space-to-Earth optical communication link surpasses the 100 Gbps record set by the same team in June 2022.

TBIRD makes passes over an ground station having a duration of about six-minutes. During that period, multiple terabytes of data can be downlinked. Each terabyte contains the equivalent of about 500 hours of high-definition video. The TBIRD communication system transmits information using modulated laser light waves. Traditionally, radio waves have been the medium of choice for space communications. Radio waves transmit data through space using similar circuits and systems to those employed by terrestrial radio systems such as WiFi, broadcast radio, and cellular telephony. Optical communication systems can generally achieve higher data rates, lower loses, and operate with higher efficiency than radio frequency systems. Continue reading “NASA Team Sets New Space-to-Ground Laser Communication Record” →

The PDP8 That Never Was: Hollow State Logic

June 9, 2023 by Al Williams 31 Comments

[Outer World Apps] noted that there was no PDP-8/V made by DEC — a variant that used vacuum tubes. So he’s decided to make one using about 320 6J6A tubes. He’s got a plan and a few boards completed — we can’t wait to see it finished.

The logic is actually done by crystal rectifiers, but the tubes do inversion. To make an and/or/invert gate requires a single triode or half of a 6J6A. A D flip flop requires three tubes or two tubes for a latch. In addition to the “crystal diodes,” the memory and I/O are a Raspberry Pi, and there are transistors to do level conversion between the tube logic and the Pi.

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