[Usagi] Whips A Chain Printer Into Shape

What does it take to get a 47-year-old printer working? [Usagi Electric] shows us it’s not too hard, even if you don’t exactly know what you’re doing.  When we last left this project, he’d tested and verified his power supply was working. This week, after a bit of cleaning, it was time to dig into the mechanics.

If you haven’t seen a chain printer in action before, definitely check one out. They’re big, loud, and sound a bit like a turbine when they spool up. The type chains on these printers never stops moving. This means the printer has to know exactly where a particular letter is before launching one of 66 hammers at it. If the timing is off, parts will fly. To the average computer user, they’re quite intimidating.

Thankfully [Usagi’s] printer was in pretty good shape. When he flipped the big power switch, there was plenty of strange noises, culminating in the test pattern of dollar signs. Probably an early reminder to customers that they needed to order more print supplies.

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A line-art diagram of the microfluidic device. On the left, in red text, it says "Fibrillization trigger (CPB pH 5.0). There is a rectangular outline of the chip in grey, with a sideways trapezoid on the left side narrowing until it becomes an arrow on the right. At the right is an inset picture of the semi-transparent microfluidic chip and the text "Negative Pressure (Pultrusion)." Above the trapezoid is the green text "MaSp2 solution" and below is "LLPS trigger (CPB pH 7.0)" in purple. The green, purple, and red text correspond with inlets labeld 1, 2, and 3, respectively. Three regions along the arrow-like channel from left to right are labeled "LLPS region," "pH drop," and in a much longer final section "Fiber assembly region."

Synthetic Spider Silk

While spider silk proteins are something you can make in your garage, making useful drag line fibers has proved a daunting challenge. Now, a team of scientists from Japan and Hong Kong are closer to replicating artificial spider silk using microfluidics.

Based on how spiders spin their silk, the researchers designed a microfluidic device to replicate the chemical and physical gradients present in the spider. By varying the amount of shear and chemical triggers, they tuned the nanostructure of the fiber to recreate the “hierarchical nanoscale substructure, which is the hallmark of native silk self-assembly.”

We have to admit, keeping a small bank of these clear, rectangular devices on our desk seems like a lot less work than keeping an army of spiders fed and entertained to produce spider silk Hackaday swag. We shouldn’t expect to see a desktop microfluidic spider silk machine this year, but we’re getting closer and closer. While you wait, why not learn from spiders how to make better 3D prints?

If you’re interesting in making your own spider silk proteins, checkout how [Justin Atkin] and [The Thought Emporium] have done it with yeast. Want to make your spider farm spiders have stronger silk? Try augmenting it with carbon.

Lawny Five Keeps Lawn Mowed, Snow Plowed

Although there’s been considerable excitement over the past half century of a Jetsons-like robotic future, outside of a few niche uses of our day-to-day lives there hasn’t been much in the way of robotic assistants coming to ease our physical household workloads. Sure, robots exist in manufacturing and other industrial settings, but the vast majority of us won’t see a robotic revolution unless we make it for ourselves. To that end, [Jim] has begun construction of a robot that can at least mow his lawn and eventually plow his driveway, among other potential tasks.

The robot, called the Lawny Five, is a tracked vehicle currently under remote control but with a planned autonomous capability. The frame includes a set of caster wheels at the front to take advantage of the differential steering of the tracks, and between everything is where the mower, plow, or other tool can sit. The attachment system is based on a 2″ receiver hitch, allowing the robot to eventually change tools at will while still preserving the usefulness of the tools in their original state. The robotic platform has been tested with the mower on a wet lawn with a 20° slope and showed no signs of struggle (and didn’t damage the grass) so it’s ready to take on more challenging tasks now as well.

With the core of the build out of the way, [Jim] is well on his way to a robotic lawnmower and potentially even an autonomous one, not to mention one with interchangeable tools that he hopes will be put to work in other ways like parking his boat in a small space by his house. For those maintaining a piece of land a little more involved than suburban turfgrass, there are other robotic platforms capable of helping out farmers with things like planting, watering, and weeding.

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3D Printing Silicone Parts

Silicone is a useful material for many purposes. Traditionally, creating something out of silicone required injection molding. That’s not difficult, but it does require a good bit of setup. As [Formlabs] points out in a recent video, there are at least three other routes to create silicone parts that utilize 3D printing technology that might fit your application better, especially if you only need a few of a particular item. You can see the video below.

The three methods are either printing silicone directly, printing a mold, casting silicone, or using high-performance elastomers, which are very silicone-like. Of course, as you might expect, some of this is aimed at prompting some of [Formlab’s] products, like a new silicone resin, and you can’t blame them for that.

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A Tube Tester Laid Bare

There’s still a mystique around vacuum tubes long after they were rendered obsolete by solid state devices, and many continue to experiment with them. They can be bought new, but most of us still come to them through the countless old tubes that still litter our junk boxes. But how to know whether your find is any good? [Rob’s Fixit Shop] took a look at a tube tester, once a fairly ubiquitous item, but now a rare sight.

To look at it’s a box with an array of tube sockets, a meter, and a set of switches to set the pinout for the tube under test. We expected it to use a common-cathode circuit, but instead it measures leakage between the grid and the other electrodes, a measure of how good the vacuum in the device is. In a worrying turn this instrument can deliver an electric shock, something he traces to a faulty indicator light leading to the chassis. We are however still inclined to see it as anything but safe, because the lack of mains isolation still exposes the grid to unwary fingers.

All in all though it’s an interesting introduction to an unusual instrument, and given a suitable isolating transformer we wouldn’t mind the chance to have one ourselves. If you need to test a tube and don’t have one of these, don’t worry. It’s possible to roll your own.

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The End Of Landlines?

Imagine if, somehow, telephones of all kinds had not been invented. Then, this morning, someone entered a big corporation board room and said, “We’d like to string copper wire to every home and business in the country. We’ll get easements and put the wires on poles mostly. But some of them will go underground where we will dig tunnels. Oh, and we will do it in other countries, too, and connect them with giant undersea cables!” We imagine that executive would be looking for a job by lunchtime. Yet, we built that exact system and with far less tech than we have today. But cell phones have replaced the need for copper wire to go everywhere, and now AT&T is petitioning California to let them off the hook — no pun intended — for servicing landlines.

The use of cell phones has dramatically decreased the demand for the POTS or plain old telephone service. Even if you have wired service now, it is more likely fiber optic or, at least, an IP-based network connection that can handle VOIP.

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Revisiting A Z80 Game From 1990

Back in the days of 8-bit computers, like no doubt many readers of similar age, we wrote little games. First in BASIC, then augmented with little machine code speed-ups. We didn’t come close to [Óscar Toledo Gutiérrez] though, who’s reverse engineering a 2K all-machine-code game he wrote back in 1990. As a tale of software archaeology it’s fascinating.

The game itself is an avoid-the-monsters platformer with plenty of ladders for the little sprite-based protagonist to run down. The computer was a Mexican homebrew educational machine with a TMS9118 display chip and an AY-3-8910 synthesizer, so the result had both color and music. His run through the code breaks it down neatly into individual sections, so it’s possible to see what’s going on without an in-depth knowledge of machine code.

He readily admits it bears all the hallmarks of an 11-year-old’s knowledge at the time, and that it has some parts less elegant, but nevertheless it’s something of an achievement at any age. It was out of date gameplay-wise in 1990 but in 1982 it could probably have been bought on a tape by eager kids. Here in 2024 he’s got it for download should you have a Colecovision or an MSX. There’s a gameplay video below the break, take a look.

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