When it comes to fields that are considered the most complex of human endeavours, the most typically cited are those of rocket science and brain surgery. Indeed, to become a surgeon is to qualify in a complex, ever-changing, and high-performance field, with a pay scale and respect to match.
The tools of surgery have changed over time, with robotic assistants becoming commonplace in recent decades. Now the latest robots are starting to outperform human surgeons in some ways. Let’s look at how that’s been achieved, and what it means for the future of medicine. Continue reading “Robotic Surgeons Are Showing Hints Of One Day Outperforming Humans”→
A few weeks ago, some tantalizing social media posts emerged from a Def Con talk, in which [Sick Codes] broke into the screen control unit for a John Deere tractor live on stage, and proceeded to play a special Deere-themed DOOM level upon it. At the time there was nothing more to go on, but we’re pleased to find out that the whole talk has been put online.
The talk starts with an introduction to the topic, to the basics of the control units within the machine and to the various different ages of Deere screen unit. We find that the earlier machines, which are still at work on farms worldwide, rely on outdated Windows CE versions, though the very latest screens run a Linux variant.
It’s one of these last screens to which he turns his attention, and we’re treated to an in-depth look at some of its secrets. After a lot of dead ends and learning exercises the final result is distilled into a pogo pin adapter for the hardware part, and a simple enough cron job to bypass one of Deere’s defenses by keeping the filesystem writable so a file can be updated. There’s a bit more detail about the special DOOM level too, as a special bonus.
PCB design starts off being a relatively easy affair — you create a rectangular outline, assign some component footprints, run some traces, and dump out some Gerber files to send to the fab. Then as you get more experienced and begin trying harder circuits, dipping into switching power supplies, high speed digital and low noise analog, things get progressively more difficult; and we haven’t even talked about RF or microwave design yet, where things can get just plain weird from the uninitiated viewpoint. [Robert Feranec] is no stranger to such matters, and he’s teamed up with one of leading experts (and one of this scribe’s personal electronics heroes) in signal integrity matters, [Prof. Eric Bogatin] for a deep dive into the how and why of controlled impedance design.
RG58 cable construction. These usually are found in 50 Ω and less commonly these days 75Ω variants
One interesting part of the discussion is why is 50 Ω so prevalent? The answer is firstly historical. Back in the 1930s, coaxial cables needed for radio applications, were designed to minimize transmission loss, using reasonable dimensions and polyethylene insulation, the impedance came out at 50 Ω. Secondarily, when designing PCB traces for a reasonable cost fab, there is a trade-off between power consumption and noise immunity.
As a rule of thumb, lowering the impedance increases noise immunity at the cost of more power consumption, and higher impedance goes the other way. You need to balance this with the resulting trace widths, separation and overall routing density you can tolerate.
Another fun story was when Intel were designing a high speed bus for graphical interfaces, and created a simulation of a typical bus structure and parameterized the physical constants, such as the trace line widths, dielectric thickness, via sizes and so on, that were viable with low-cost PCB fab houses. Then, using a Monte Carlo simulation to run 400,000 simulations, they located the sweet spot. Since the via design compatible with the cheap fab design rules resulted often in a via characteristic impedance that came out quite low, it was recommended to reduce the trace impedance from 100 Ω to 85 Ω differential, rather than try tweak the via geometry to bring it up to match the trace. Fun stuff!
We admit, the video is from the start of the year and very long, but for such important basic concepts in high speed digital design, we think it’s well worth your time. We certainly picked up a couple of useful titbits!
Now we’ve got the PCB construction nailed, why circle back and go check those cables?
While it isn’t for everyone, some of the best creators we know are experts at working with textiles. While the art is ancient, it isn’t easy and requires clever tools. [Lauren] collected a few 3D prints that can help you with knitting, crochet, and even a knitting loom.
Some of the designs are pretty basic like the yarn bowl, or pretty easy to figure out like the simple machine for re-spooling wool. We were frankly surprised that you can 3D print a crochet hook, although the post does mention that breaking them is a real problem.
We were really impressed though, with the sock knitting machine. There are actually a few of these out there, and you can see a similar one in the video below. Of course, like a RepRap printer, it needs “vitamins” in the form of metal rods, fasteners, and the like. There’s also a portable knitting loom which looked interesting.
We aren’t adept enough with fabric arts to know if these tools are serious contenders compared to commercial products, but we have to admit the sock knitting machine looks like it could be. We recently saw a sophisticated loom, although that might be a bit more than most people need. We have looked at open-source knitting machines, too. Of course, if you’d rather not create with textiles, you can always 3D print on them, instead.
If you’ve bought a miter saw in the past few years, you might have noticed the LED “laser” that came with it. The goal was to show where on the piece the saw was going to cut. But over a year or two, you might have found the laser to have drifted or skewed into a crooked line. [Fisher] decided that his after-market laser wasn’t entirely accurate enough and added a shadow line instead. (Video, embedded below the break.)
The blade has a thickness (known as kerf), and with a laser to one side, you can only accurately cut on one side of the line. A shadow line works differently. By shining a line at the top of the blade, you get a mark where the blade will cut precisely. You can also see your marks as the laser doesn’t shine over them. Previously, [Fisher] had tried to use LED strips, but after a comment suggested it, he found a sewing light on a gooseneck. It worked great as a small compact light fitting the blade housing. After some quick modifications, hot glue, and duct tape, the light was installed, and the wires were routed while still allowing the saw its full range of motion.
Good news out of Mars from the little lunchbox that could — in the seven times that MOXIE has run since it arrived in February 2021, it has reached its target production of six grams of oxygen per hour, which is in line with the output of a modest tree here on Earth. The research team which includes MOXIE engineers report that although the solid oxide electrolysis machine has shown it can produce oxygen at almost any time or day of the Martian scale, they have not shown what MOXIE can do at dawn or dusk, when the temperature changes are substantial, but they say they have ‘an ace up (their) sleeve’ that will let them do that. We can’t wait to see what they mean.
In other, somewhat funnier space news — early last Sunday morning, the ESA’s Solar Orbiter was cruising by Venus as part of a gravity-assist maneuver to get the Orbiter closer to the Sun. Two days before the Orbiter was to reach its closest point to the spacious star, it spat a coronal mass ejection in the general direction of both Venus and the Orbiter (dibs on that band name), as if to say ‘boo’. Fortunately, the spacecraft is designed to withstand such slights, but the same cannot be said for Venus — these events have their way with Venus’ atmosphere, depleting it of gasses.
Here’s a neat resource from [MSRaynsford] that is worth bookmarking for anyone who gets creative with laser engravers, CNC routers, or drawing robots: SVGFonts are single-line symbol fonts that [MSRaynsford] created for his laser-cut and engraved cryptex puzzle boxes. They provide an easy way to engrave text as symbols.
Single-line fonts for engraving that include a runic-looking alphabet, a Greek-inspired set, and two symbol sets based on Flag Semaphore.
CNC engraving of letters and symbols is one of those things that seems simple, but is actually more complex than it may appear. It is often desirable to use a tool to engrave symbols with a single line, in much the same way a person would write them if using a pen. But fonts and art for letters and numbers aren’t normally a single line. Thankfully there is a solution in the form of Hershey text, an extension for which is included in Inkscape. It turns out that Hershey Fonts have their origin back in the 1960s, when the changing landscape of electronics and industry opened new opportunities and demanded new solutions.
That’s why, when [MSRaynsford] needed fonts in different styles and symbols for creating his puzzle boxes, he had to design them himself and they had to be single-line vector art, just like Hershey Text. The small collection includes English letters designed to resemble a runic alphabet, a Greek-inspired series, and two coded alphabets based on flag semaphore.
