Building And Testing A DIY Robot Actuator

June 17, 2026 by No comments

[Brandon Lai] is hoping to build a humanoid robot. To that end, he’s going to need some actuators, and decided to design his own. His second pass at this turned out pretty well, with a few snags found along the way.

Target specs were a actuator that could run at 40 to 60 rpm while delivering 20 Nm of torque for up to an hour continuously. The design was inspired by an MIT research paper, with [Brandon] making a few mods to suit his use case. Where the MIT design uses an inbuilt planetary gearbox, this build substitutes a cycloidal gearbox with a hope it will provide better torque capacity with less backlash. The design is based around a hand-wound stator made with an off-the-shelf core, while using custom CNC parts and 3D printed components for the motor housing itself.

Testing revealed some limitations. Running off a benchtop power supply with limited current, the motor was only able to achieve 7 Nm of torque, though a better PSU would probably improve this. [Brandon] also noted excessive backlash in the cycloidal gearbox, due to poor tolerances, and the $400 construction cost came in well over budget. Still, [Brandon] hopes to tackle many of these problems in a future revision. CAD files are available online if you’d like to dig deeper into the design.

We’ve featured plenty of great actuator builds over the years. Video after the break.

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2026 Frikkin Lasers Contest: Steampunk, 360 O-Scope Does It With Tubes

June 17, 2026 by 2 Comments

Audiophiles all know everything sounds better fed through vacuum tubes, but did you know visualizers look better with them, too? That’s what we’re forced to conclude looking at the Tachyscope Laser, a 360-degree oscilloscope display that is [Daniel Ross]’s entry into the ongoing Frikkin Lasers contest.

The diagram makes it look easier than building it probably was.

The laser is a good old-fashioned helium–neon tube — something we see less and less of in this era of solid state lasers — and the wavelength gives the waveform display a retro charm. The actual display is unique in our experience, with the beam shining up through a hollow shaft to bounce off a galvanometer mirror on a spinning platform. Galvo sweeps the laser across a translucent target, which creates the waveform by persistence of vision as it spins at 100 RPM or so.

Does the fact that the audio signal feeds through a tube amp to drive the single galvanometer actually improve the visuals? Only in the sense that those tubes make the steampunk-style enclosure look really, really cool, as does the exposed laser tube. That all of the steampunk elements obviously have a point to them rather than just being a another “glue some gears on it” project is icing on the laser-flavored cake.

The contest runs until July 23rd, so there’s lots of time to get laserin’ — and remember that there are categories for DIY lasers and anything that isn’t a display, just in case you think this project puts the bar too high for a light show. We’ve actually featured one of [Daniel]’s tachyscope waveform visualizers before, but that one, madly enough, spun an actual CRT.

2026 Hackaday Freaking Lasers Contest

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Skip The Embedded Filesystem With The TAR-like UTFS Format

June 17, 2026 by 7 Comments

If you need to store some data on a resource-constrained embedded platform, the prospect of dragging in a dependency for something like FAT filesystem access to flash or other storage medium can seem rather daunting. Not only is your binary size now significantly larger, the overhead of these filesystems is also not insignificant as they were not really designed for this type of environment. Here [Drew Gaylo]’s UTFS format is an interesting alternative to just writing raw binary data to said storage medium.

As explained in the accompanying introduction article, the basic idea is similar in scope but very much slimmed down compared to the venerable Tape ARchive (TAR) format, hence the Micro (µ) Tar File System name. The provided UTFS implementation is quite small, spanning two source files in C99 with zero heap usage. Targeting a custom store medium requires implementing one read and one write function to match the underlying platform.

A couple of examples are also provided, covering using the built-in Flash of a SAMD20 MCU and the EEPROM of an ATmega328. Compared to raw binary data that’d have to be fully rewritten, UTFS allows for sections of the storage to be accessed as files and thus updated in-place.

Ask Hackaday: What Ever Happened To The Hero Nerd?

June 17, 2026 by 75 Comments

Knowing absolutely nothing about you other than the fact that you’re currently reading Hackaday, I can predict with a high degree of certainty that we’re both fond of at least a few of the same movies. That’s not to say they’re necessarily our favorite works of art. Indeed, in some cases they may even be objectively bad films. But the memory of them has stuck with us — and by extension nearly everyone else in the hacker and maker community — for decades.

Even if you don’t remember all the little details, you’ll never forget the names: movies like WarGames, Ghostbusters, Back to the Future, and Short Circuit. Stories that showed smart people using their intellect and a bit of cobbled together hardware to triumph over the bad guys. The tech wasn’t always believable, sometimes it was downright farcical. But they made it seem real, and by the end of the story when they won the day using brains and a soldering iron rather than fists or a gun, the minutia of how it all worked wasn’t really that important anyway.

It’s not a stretch to say that films such as these helped put many of us on a path towards science and technology. For those with an interest in more cerebral pursuits, seeing a scientist or an engineer save the day was hugely influential. How many engineers got their start watching Scotty frantically eke just a bit more power out of the Enterprise?

But as we recently discussed some of these classic movies behind the scenes here at Hackaday, it struck us that all of the best examples we could come up with were now 20, 30, or even 40 years old. That’s not to say there aren’t a few contemporary standouts, but they mostly seem to be biopics or other historical dramatizations which don’t quite scratch the same itch. Even so, none of them appear to have had the cultural impact necessary to stand the test of time in the same way their predecessors have.

So where have all of Hollywood’s heroic nerds gone, and what does it mean for future generations if these niche role models are no longer represented?

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Figure showing the simulated path of gas released in GEO to the magentosheath.

An Orbital StormWall Could Mitigate The Next Carrington Event

June 17, 2026 by 30 Comments

The Carrington Event was the most intense geomagnetic storm ever recorded. In September 1859, auroras were visible as close to the equator as Columbia and some telegraph stations were severely damaged by current induced in the lines. If a similar event occurred today, with a lot more more wiring to pick up current than just an embryonic telegraph network, the results would almost certainly be cataclysmic.

Various modifications to the grid have been proposed to avoid another storm of that magnitude bringing on a new dark age, but a recent paper in the journal Space Weather proposes a more radical solution: using the sun’s energy to create a massive barricade in space.

Time evolution of a simulated geomagnetic storm, with and without the StormWall.

While the authors of the paper refer to this concept by the compelling name StormWall, it’s not a physical wall. It’s actually just gas, likely of alkali metal atoms, to be deployed by solar-powered satellites.

To oversimplify, the proposal is to release lots and lots of neutral gas in Geosynchronous Earth Orbit (GEO), in what the researchers call “artificial mass loading” — the neutral gas would of course be ionized by the storm, but in so doing could absorb up to 50% of the incoming energy of the geomagnetic storm, frustrating its coupling to Earth’s magnetosphere. As a bonus, it would protect not just terrestrial assets like the power grid, but everything in a lower orbit than the mass load: everything from communication satellites in GEO to the International Space Station. Assuming its hasn’t been reduced to debris laying at the bottom of Point Nemo by then, anyway.

In simulations, the StormWall required 384,048 kg of gas, which is not exactly trivial. But even accounting for tanking, the researchers estimate that would only take about six launches of SpaceX’s Starship. Though that does assume its GEO capabilities end up being roughly equivalent to the massive vehicle’s projected 100-tons-to-Mars payload capacity.

It’s certainly an interesting hack to solve a problem that has caused a lot of worry these past decades. If you’re interested in learning more about the record-setting geomagnetic storm, we have a piece about the 1859 Carrington Event that should give you plenty of anxiety about the frailty of our modern infrastructure.

Building An Organic Flow Battery Based On Green Tea

June 17, 2026 by 7 Comments

As simple of a concept flow batteries are, the used chemicals can still be somewhat problematic in the context of a school experiment. To this end [Markus Bindhammer] decided to implement a flow battery version that uses compounds from green tea for its electrolyte, based on a German research paper from 2016.

The flow battery construction from the paper by Rosenberg et al., 2016.

These organic flow batteries can use gallic acid, pyrogallol as well as the polyphenols in green tea, making them rather safe even in the hands of more careless students. The demonstrated flow battery uses a carbon electrode with activated carbon around it to increase surface area, a platinum wire electrode, and a graphite foil as third electrode.

In the paper a silver electrode is also used, along with the additional electrodes, and a terracotta flower pot as the barrier between the carbon and graphite electrodes, with [Markus] further explaining that there are fortunately cheaper options than what he is using, especially with the flower pot instead of a special ceramic vessel.

The electrolyte solution has epigallocatechin gallate (EGCG) dissolved in it, which here comes in the form of finely ground green tea powder (commonly known as matcha), which so happens to be pretty rich in this substance. In the below graphic by [Markus] you can see the complete set of solutions and other relevant details.

Of course, the performance of this type of flow cell isn’t amazing, with a cell voltage of less than a volt and a few mA of current, but it’s enough to spin a small fan, and to light up a few LEDs. This would be more than enough to demonstrate the reaction and flow cells in general, as long as you don’t mind donating some tasty matcha to science.

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