3D Printing LEGO-like Blocks

June 10, 2023 by 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 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.
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 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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TeraByte InfraRed Delivery (TBIRD)

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

June 9, 2023 by 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 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.

Continue reading “The PDP8 That Never Was: Hollow State Logic” →

Recreating An Analog TV Test Pattern

June 9, 2023 by 25 Comments

While most countries have switched to digital broadcasting, and most broadcasts themselves have programming on 24/7 now, it’s hard to remember the ancient times of analog broadcasts that would eventually stop sometime late at night, displaying a test pattern instead of infomercials or reruns of an old sitcom. They were useful for various technical reasons including calibrating the analog signals. Some test patterns were simply camera feeds of physical cards, but if you wanted the most accurate and reliable test patterns you’d need a Philips pattern generator which created the pattern with hardware instead, and you can build your own now because the designs for these devices were recently open-sourced. Continue reading “Recreating An Analog TV Test Pattern” →

These 3D Printed Biocatalytic Fibers Scrub Carbon Dioxide

June 9, 2023 by 12 Comments

On today’s episode of “What If?” — what if the Apollo 13 astronauts had a 3D printer? Well, for one thing, they may have been able to avoid all the futzing with duct tape and procedure list covers to jury rig the lithium hydroxide filters, at least if they’d known about these 3D printed enzymatic CO2 filters. And time travel…they probably would have needed that too.

A bit of a stretch, yes, but environmental CO2 scrubbing is at least one use case for what [Jialong Shen] et al from the Textile Engineering Department at North Carolina State University have developed here. The star of the show isn’t so much the 3D printing — although squirting out a bio-compatible aerogel and cross-linking it with UV light on the fly is pretty cool. Rather, the key to developing a CO2-scrubbing textile is carbonic anhydrase, or CA, a ubiquitous enzyme that’s central to maintaining acid-base homeostasis. CA is a neat little enzyme that coordinates a zinc ion in its active site and efficiently catalyzes the addition of water to carbon dioxide to produce bicarbonate and hydrogen ions. A single CA molecule can catalyze the conversion of up to a million CO2 molecules per second, making it very attractive as a CO2 filter.

In the current work, an aerogel of poly(ethylene glycol) diacrylate/poly(ethylene oxide) (PEG-DA/EO) was used to entrap CA molecules, holding them in place in a polymer matrix to protect them from denaturation while still allowing access to gaseous CO2. The un-linked polymers were mixed with photoinitiators and a solution of carbonic anhydrase and extruded through a fine nozzle with a syringe pump. The resulting thread was blasted with 280–450 nm UV light, curing the thread instantly. The thread is either wound up as a mono-filament for later weaving or printed directly into a 2D grid.

The filament proved to be quite good at CO2 capture, managing to scavenge 24% of the gas from a mixture passed over it. What’s more, the entrapped enzyme appears to be quite stable, surviving washes with various solvents and physical disruptions like twisting and bending. It’s an exciting development in catalytic textiles, and besides its obvious environmental uses, something like this could make cheap, industrial-scale bioreactors easier to build and run.

Photo credits: [Sen Zhang] and [Jialong Shen], NC State; [Rachel Boyd], Spectrum News 1

[via Phys.org]