Built at a cost of more than $150 billion over the last twenty-five years, the International Space Station is arguably one of humanity’s greatest engineering triumphs. Unfortunately, unlike Earthly construction feats such as the Hoover Dam, Burj Khalifa, or the Millau Viaduct, you can’t visit it in person to really appreciate its scale and complexity. Well, not unless you’ve got the $50 million or so to spare to buy a seat on a Dragon capsule.
Which is why the team behind the ISS Mimic project are trying to make the ISS a bit more relatable. The open source project consists of a 3D printable 1:100 model of the Station, which is linked to the telemetry coming down from the real thing. A dozen motors in the model rotate the solar arrays and radiators to match the positions of their full-scale counterparts, while LEDs light up to indicate the status of various onboard systems.
Since the first combat robots emerged around three decades ago, it seems as though every conceivable configuration has been tried at some point or other. Whether it’s a two-wheeled wedgebot, a walker, a four-wheeled flip-bot, or whatever, someone’s already been there. But how about a self-righting taco with a novel two-wheel drive system? It’s called Taco Tuesday, its team lead [Carter Hurd] has sent us the video below the break, and it’s worth a second look because the technique might find a place outside the arena.
So what exactly is novel about this bot? It has a single big fat wheel near the front in a longitudinal direction, and a larger slimmer one at the back in a transverse direction. The former wheel propels it around the arena while the latter wheel acts as a rear-wheel steering system, allowing it to pivot round and face an attacker very quickly indeed.
It’s this maneuverability which we think could find an application in other machines, though the same problem they have of sideways friction on that rear wheel would need to be overcome.
The video follows the bot through a BattleBots competition in Las Vegas, and shows us some of the damage they receive in combat. The drive system needs a bit more refinement, but this outing certainly proves it has plenty of potential.
Do you speak GAL? [Peterzieba] does, and has pulled together a collection of documents and tools so that you can too. There’s a dividing line in electronic engineering education, between those who were taught about FPGAs, and those who weren’t. Blurring that line slightly is gate array logic (GAL). These devices were a preceursor to the FPGA, with a much simpler structure, and usually in those days UV-erasable in the same manner as an EPROM. And oddly enough, they, or at least their successor compatible parts, are still available, and as handy DIP devices that talk to 5 volt logic.
The guide goes into detail about the parts, the terminology surrounding them, and the CUPL language which raises a few memories for us. There are several possible workflows, including for those not faint of heart, the possibility of writing a fusemap by hand. We’re impressed by that one.
If these devices interest you, our colleague Bil Herd wrote a two-part guide (part one, and part two) which should answer your questions.
The walking tank concept has always captured imaginations. Whether you’re talking about the AT-AT walkers of Star Wars, or the Dreadnoughts from Warhammer 40,000, they are often portrayed in fiction as mighty and capable foes on the battlefield. These legged behemoths ideally combine the firepower and defense of traditional tanks with the versatility of a legged walking frame.
Despite their futuristic allure, walking tanks never found a practical military application. Let’s take a look at why tracks still rule, and why walking combat machines are going to remain firmly in the realm of fiction for the foreseeable future.
We’ve devoted a fair amount of virtual ink here to casting shade at self-driving vehicles, especially lately with all the robo-taxi fiascos that seem to keep cropping up in cities serving as testbeds. It’s hard not to, especially when an entire fleet of taxis seems to spontaneously congregate at a single point, or all it takes to create gridlock is a couple of traffic cones. We know that these are essentially beta tests whose whole point is to find and fix points of failure before widespread deployment, and that any failure is likely to be very public and very costly. But there’s someone else in the self-driving vehicle business with way, WAY more to lose if something goes wrong but still seems to be nailing it every day. Of course, we’re talking about NASA and the Perseverance rover, which just completed a record drive across Jezero crater on autopilot. The 759-meter jaunt was completely planned by the onboard AutoNav system, which used the rover’s cameras and sensors to pick its way through a boulder-strewn field. Of course, the trip took six sols to complete, which probably would result in negative reviews for a robo-taxi on Earth, and then there’s the whole thing about NASA having a much bigger pot of money to draw from than any start-up could ever dream of. Still, it’d be nice to see some of the tech on Perseverance filtering down to Earth.
[Thomas Sanladerer] wanted to make 3D prints using carbon fiber and was surprised that it was fairly inexpensive and worked well, although he mentions that the process is a bit intense. You can learn what he found out in the video below.
He used an advanced PLA that can endure more temperature than normal PLA. That’s important because the process uses heat and the carbon fiber resin will produce heat as it cures. The first step was to print a mold and, other than the material, that was pretty straightforward.
When you’ve been a fact-sponge for electronics trivia for over four decades, it’s not often that an entire class of parts escapes your attention. But have you seen the Skiatron? It’s a CRT that looks like a normal mid-20th-century tube, until it’s switched on. Then its secret is revealed; instead of the glowing phosphor trace we’d expect, the paper-white screen displays a daylight-readable and persistent black trace. They’re invariably seen in videos of radar installations, with the 360 degree scans projected onto large table-top screens which show the action like a map. It’s like e-ink, but from the 1940s. What’s going on?
The tenebrescent mineral Hackmanite, before and after UV exposure. Leland Green…, CC BY-SA 2.0 and CC BY-SA 2.0.
The phosphor coating on a traditional CRT screen is replaced by a halide salt, and the property on which the display relies is called tenebrescence, changing colour under the influence of radiation. This seems most associated online with UV treatment of some minerals and gemstones to give them a prettier look, and its use a s a display technology is sadly forgotten.
A high-school physics understanding of the phenomenon is that energy from the UV light or the electron beam in the case of the tube, places some electrons in the crystal into higher energy levels, at which they absorb some visible light wavelengths. This is reversible through heat, in some substances requiring the application of heat while in others the heat of room temperature being enough. Of course here at Hackaday we’re hands-on people, so into the EPROM eraser went a small amount of table salt in a makeshift dish made of paper, but sadly not to be rewarded by a colour change.
On a real dark-trace CRT the dark trace would be illuminated from behind by a ring light round the glass neck of the tube. An interesting aside is that, unlike phosphor CRTs, they were more suitable for vertical mounting. It seems that small amounts of phosphor could detach themselves from a vertically mounted screen and drop into the electron gun, something that wasn’t a problem for tenebrescent coatings.
This display tech has shuffled off into the graveyard of obsolescence, we’re guessing because CRT technology became a lot better over the 1950s, and radar technologies moved towards a computerised future in which the persistence of the display wasn’t the only thing keeping the information on the screen. It seems at first sight to be a surprise that tenebrescent coatings have never resurfaced in other displays for their persistence, but perhaps there was always a better alternative whether it was ultra-low-power LCDs or more recently e-ink style devices.
For more bleeding-edge 1950s radar displays, we’ve previously brought you Volscan, a radar with an early form of GUI, which no doubt was one of those which consigned dark-trace CRTs to history.
![The robot with [Carter] sitting behind it](https://hackaday.com/wp-content/uploads/2023/10/taco-tuesday-drive.jpg)
