Moteus Open Source BLDC Controller Gets Major Upgrade

[Josh Pieper] of mjbots Robotic Systems just released a major revision to his moteus open sourced brushless DC (BLDC) electric motor controller. The update adds a flexible I/O subsystem which significantly expands the kinds of feedback encoders and peripherals the controller can accept. In the video below the break, [Josh] walks through eleven different example configurations. If you prefer, these examples are also presented in article form on his blog.

The moteus controller originally came about when [Josh] was developing the quad A0, an open source dynamic quadruped robot, along the lines of the MIT Mini Cheetah or Boston Dynamics robotic dogs, and wasn’t satisfied that existing controllers could do the trick. It’s a compact 50 mm square board based on an STM32G4, has an integrated magnetic encoder, and accepts external sensor connections. Interfacing with the board is via CAN-FD using a register-based scheme. A Python GUI tool provides name-based register access via a logical tree structure as well as real-time telemetry plotting capabilities for diagnostic and configuration tasks.

If you are using BLDC motors in your projects, definitely check this out. Even if you’re not using a moteus controller, [Josh]’s demonstrations of the various encoder feedback technologies is very interesting and educational. The entire project is open source, and both the hardware and software design files can be found on the project’s GitHub repository. For some users, this may be a major factor, considering that the latest ODrive BLDC controller offering has become closed source.

We wrote about the mjbots quad A0 in 2019, and you can follow the moteus project over on Hackaday.io. We also found this interesting video by [Skyentific] comparing three popular open source BLCD controllers including the moteus (second video below the break). There’s also the SimpleFOC project we covered last year if you want to dig in and learn more about field-oriented control of BLDC motors. Thanks to [Androiddrew] for the tip.

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A 3D Printer Big Enough To Print A Kayak

When one of your design goals for a 3D printer is “fits through standard doors,” you know you’re going to be able to print some pretty big stuff. And given that the TAUT ONE printer by [Nathan Brüchner] could easily be mistaken for a phone booth, we’d say it’ll be turning out some interesting prints.

The genesis for this beast of a printer came from the Before Times, with the idea of printing a kayak. [Nathan] leveraged his lowdown time to make it happen, going through three prototypes. Each featured a print bed of 1,000 mm x 550 mm with 1,100 mm of Z-height, and the overall footprint fits a standard Euro-pallet. It uses a CoreXY design to move the dual-filament hot end, which has ducting for taking cooling air from outside the cabinet. And the machine has all the bells and whistles — WiFi, an internal camera, filament sensors, and a range of environmental controls.

In a nod to making it easier to build, [Nathan] kept all the custom parts either laser cut or 3D-printed — no mill or lathe required. He also points out that he used only quality components, which shows in the price — about 3,000€. That seems like a lot to be able to print kayaks that you can buy for fraction of that amount, but we certainly appreciate the potential of this printer, and the effort that went into making it work.

Need A Linux Kernel Module? Scratch That

If you have been for (or against) Rust in the Linux kernel, get ready for a Linux kernel module written in… Scratch. That’s right. Scratch, the MIT-developed language with blocks popular for teaching kids to code. We didn’t mean “from scratch.” We meant IN Scratch. The bootstrap code and Makefile is out there on GitHub.

Of course, it is a simple module and the reason it is possible is because of the scratchnative system that lets you compile Scratch into C code. If you want to look at the decidedly simple code, you can open it in your browser.

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When Is An LED A Lamp? When It’s 50mm Wide

Call us childlike, but we sure do get a kick out of both larger-than-life and miniature things, especially when they work as their “normal-sized” counterparts do. So you can imagine our glee when we saw [JGJMatt]’s 50mm LED lamp, which looks like a giant version of something you might have wired up on your bench at any given moment — a bent-legged LED, wired up and ready to blink.

[JGJMatt] started by designing a mold in Fusion360 to make the lens, which he then printed in PLA. However, due to the heat generated by curing resin (especially all enclosed like that), he recommends using PETG or ABS instead to avoid any potential warping issues.

This is where things get a bit dangerous. For the internals, [JGJMatt] went all out, hand forming a reflector cup out of brass pipe, and the anode and cathode plates from flat 1 mm brass stock, plated to a silvery gray finish. The light source itself is a 1 W cool white LED that sits in the reflector cup, safe under a layer of epoxy mixed with a bit of yellow paint that represent the phosphor layer in a standard 5 mm white LED.

Once the innards were ready, it was time to cast the huge lens with them tucked safely inside. After the resin cured, [JGJMatt] sanded away the layer lines and airbrushed it with clear lacquer to clear up the lens and protect it from yellowing down the road. Then it was just a matter of bending the legs to form a stand, and wiring it up. What an awesome way to light up your workbench! Or anywhere, really.

This isn’t the first time we’ve seen a giant, working LED, though it’s probably only the second one since [Mike Szczys] saw some in the flesh at Maker Faire: Rome way back in 2019. Those are for sale on Tindie, BTW, though the shop is on holiday for the foreseeable, so you’ll have to make your own for now.

AJAX COMMAND Radio Is An Oldie But Goodie

If you are a certain age, it is hard to wrap your head around the fact that an old radio might have transistors — the old ones all had tubes, right? But a radio from the 1960s or 1970s is reaching the 60+ year mark and people are restoring old transistor sets. [Adam] picked up his first old radio, a 1970s vintage Ajax Command S-74.

He was fortunate. The only repair needed was to replace a corroded battery holder and clean up the mess from the batteries. You can hear the radio doing its thing in the video below.

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Hackaday Links: July 3, 2022

Looks like we might have been a bit premature in our dismissal last week of the Sun’s potential for throwing a temper tantrum, as that’s exactly what happened when a G1 geomagnetic storm hit the planet early last week. To be fair, the storm was very minor — aurora visible down to the latitude of Calgary isn’t terribly unusual — but the odd thing about this storm was that it sort of snuck up on us. Solar scientists first thought it was a coronal mass ejection (CME), possibly related to the “monster sunspot” that had rapidly tripled in size and was being hyped up as some kind of planet killer. But it appears this sneak attack came from another, less-studied phenomenon, a co-rotating interaction region, or CIR. These sound a bit like eddy currents in the solar wind, which can bunch up plasma that can suddenly burst forth from the sun, all without showing the usually telltale sunspots.

Then again, even people who study the Sun for a living don’t always seem to agree on what’s going on up there. Back at the beginning of Solar Cycle 25, NASA and NOAA, the National Oceanic and Atmospheric Administration, were calling for a relatively weak showing during our star’s eleven-year cycle, as recorded by the number of sunspots observed. But another model, developed by heliophysicists at the U.S. National Center for Atmospheric Research, predicted that Solar Cycle 25 could be among the strongest ever recorded. And so far, it looks like the latter group might be right. Where the NASA/NOAA model called for 37 sunspots in May of 2022, for example, the Sun actually threw up 97 — much more in line with what the NCAR model predicted. If the trend holds, the peak of the eleven-year cycle in April of 2025 might see over 200 sunspots a month.

So, good news and bad news from the cryptocurrency world lately. The bad news is that cryptocurrency markets are crashing, with the flagship Bitcoin falling from its high of around $67,000 down to $20,000 or so, and looking like it might fall even further. But the good news is that’s put a bit of a crimp in the demand for NVIDIA graphics cards, as the economics of turning electricity into hashes starts to look a little less attractive. So if you’re trying to upgrade your gaming rig, that means there’ll soon be a glut of GPUs, right? Not so fast, maybe: at least one analyst has a different view, based mainly on the distribution of AMD and NVIDIA GPU chips in the market as well as how much revenue they each draw from crypto rather than from traditional uses of the chips. It’s important mainly for investors, so it doesn’t really matter to you if you’re just looking for a graphics card on the cheap.

Speaking of businesses, things are not looking too good for MakerGear. According to a banner announcement on their website, the supplier of 3D printers, parts, and accessories is scaling back operations, to the point where everything is being sold on an “as-is” basis with no returns. In a long post on “The Future of MakerGear,” founder and CEO Rick Pollack says the problem basically boils down to supply chain and COVID issues — they can’t get the parts they need to make printers. And so the company is looking for a buyer. We find this sad but understandable, and wish Rick and everyone at MakerGear the best of luck as they try to keep the lights on.

And finally, if there’s one thing Elon Musk is good at, it’s keeping his many businesses in the public eye. And so it is this week with SpaceX, which is recruiting Starlink customers to write nasty-grams to the Federal Communications Commission regarding Dish Network’s plan to gobble up a bunch of spectrum in the 12-GHz band for their 5G expansion plans. The 3,000 or so newly minted experts on spectrum allocation wrote to tell FCC commissioners how much Dish sucks, and how much they love and depend on Starlink. It looks like they may have a point — Starlink uses the lowest part of the Ku band (12 GHz – 18 GHz) for data downlinks to user terminals, along with big chunks of about half a dozen other bands. It’ll be interesting to watch this one play out.

Testing A Tube Without A Tube Tester

[M Caldeira] needed to test a tube and didn’t have a spare to do the old swap test. He also didn’t have a tube tester handy. Drawing inspiration from a 2015 video, he managed to cobble up an ad hoc tube tester using stuff around the workbench. You can see a video of the process below.

To duplicate his effort, you are going to need a few meters. Good thing they are relatively cheap these days. Usually, a tube tester has a way to adjust all the different parameters for the tube, but there’s no reason you can’t just set those parameters using your testbench power supplies.

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