Tinkering With Klipper: Making The ManiPilator Robotic Arm

[Leo Goldstien]’s entry into the world of robotics has been full of stops and starts. Like many beginners, he found traditional robotics instructions overwhelming and hard to follow, bogged down with dense math that often obscured the bigger picture. So he decided to approach things differently and create something with his own hands. The result? A 3D-printed robotic arm he affectionately calls “ManiPilator.”

This article is the first in a three-part series documenting [Leo]’s hands-on approach to learning robotics from the ground up. Building ManiPilator became an opportunity to learn by doing, and the project took him on a journey of experimenting, failing, and eventually succeeding in tasks that seemed deceptively simple at first glance. Each hurdle provided him with insights that more traditional learning methods hadn’t delivered. Below is one of the videos [Leo] captured, to show one step in the process: doing a check using multiple motors.

To make his project work, [Leo] relied on open-source software like Klipper, piecing together code and hardware in a way that made sense to him. In sharing his story, he offers fellow beginners an approachable perspective on robotics, with practical insights and candid reflections on the challenges and breakthroughs.

[Leo]’s project shows that there’s more than one way to start exploring robotics, and that sometimes the best way to learn is simply to dive in and start building. Follow along with his journey as he tackles the complexities of robotics, one step at a time.

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Tearing Down A Digital Scope From ’78

If you’re a fan of vintage electronics and DIY tinkering, you’ll find this teardown by [Thomas Scherrer] fascinating. In a recent video, he delves into a rare piece of equipment: the Data Lab Transient Recorder DL 901. This device looks like a classic one-channel oscilloscope, complete with all the knobs and settings you’d expect.

The DL 901, made by Data Laboratories Ltd., is a mystery even to [Thomas], who couldn’t find any documentation online. From the DC offset and trigger settings to the sweep time controls, the DL 901 is equipped to handle slow, high-resolution analog-to-digital conversion. The circuitry includes TTL chips and a PMI DAAC 100, a 10-bit digital-to-analog converter. [Thomas] speculates it uses a successive approximation technique for analog-to-digital conversion—a perfect blend of analog finesse and digital processing for its time.

Despite its intriguing features, the DL 901 suffers from a non-responsive analog input system, limiting the teardown to a partial exploration. For those who enjoyed past Hackaday articles on oscilloscope teardowns and analog tech, this one is a treat. Watch the video to see more details and the full process of uncovering this vintage device’s secrets.

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3D Printed Hydrofoil Goes From Model Scale To Human Scale With Flight Controller

Hydrofoils have been around for several decades, but watching a craft slice through the water with almost no wake never get old. In the videos after the break, [rctestflight] showcases his ambitious project: transforming a standup paddleboard into a rideable hydrofoil with active stabilization.

Unlike conventional electric hydrofoil boards that depend on rider skill for balance, [rctestflight] aims to create a self-stabilizing system. He began by designing a small-scale model, complete with servo-controlled ailerons and elevators, dual motors for differential thrust, and a dRehmFlight flight controller. A pair of sonar sensors help the flight controller maintain constant height above the water. The wings are completely 3D printed, with integrated hinges for flight control surfaces slots for wiring and control components. It’s better suited for 3D printing than RC aircraft since it’s significantly less sensitive to weight, allowing for more structural reinforcement. The small scale tests were very successful and allowed [rctestflight] to determine that he didn’t need the vertical stabilizer and rudder.

The full-sized version features a scaled up wing, larger servos and motors attached to an 11-foot standup paddleboard — minus its rear end — mounted on commercially available e-foil booms. A foam battery box stores a hefty LiFePO4 battery, while the electronics from the smaller version are repurposed here. Despite only catching glimpses of this larger setup in action at the end of the video, it promises an excitingly smooth lake ride we would certainly like to experience.

We’ve seen several 3D printed hydrofoils around here, but this promised to be the largest successful attempt. Don’t fail us [Daniel].

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2View: The Self-Erasing VHS Tape With Paperclip Hack

The back of the 2View VHS box. The instructions are all in Dutch, as its (sole) launch market. (Credit: Techmoan, YouTube)
The back of the 2View VHS box. The instructions are all in Dutch, as its (sole) launch market. (Credit: Techmoan, YouTube)

Over the decades the video and music industries have tried a wide range of ways to get consumers to buy ‘cheaper’ versions of albums and music, but then limit the playback in some way. Perhaps one of the most fascinating ones is the 2View, as recently featured by [Matt] over at Techmoan on Youtube. This is a VHS tape which works in standard VHS players and offers you all the goodness that VHS offers, like up to 512 lines of PAL video and hard-coded ads and subtitles, but also is restricted to just playing twice. After this second playback and rewinding, the tape self-erases and is blank, leaving you with just an empty VHS tape you can use for your own recordings.

As a form of analog restrictions management (ARM) it’s pretty simple in how it works, with [Matt] taking the now thankfully erased Coyote Ugly tape apart for a demonstration of the inside mechanism. This consists out of effectively just two parts: one plastic, spring-loaded shape that moves against one of the tape spools and follows the amount of tape, meaning minutes watched, and a second arm featuring a permanent magnet that is retained by an inner track inside the first shape until after rewinding twice it is released and ends up against the second spool, erasing the tape until rewound, after which it catches in a neutral position. This then left an erased tape that could be safely recorded on again.

Although cheaper than a comparable VHS tape without this limit, 2View was released in 2001, when in the Netherlands and elsewhere DVDs were demolishing the VHS market. This, combined with the fact that a simple bent paperclip could be stuck inside to retain the erase arm in place to make it a regular VHS tape, meant that it was really a desperate attempt that quickly vanished off the market

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Automated Pixel Art With Marbles

Marble machines are a fun and challenging reason to do engineering for the sake of engineering. [Engineezy] adds some color to the theme, building a machine to create 16×16 marble images automatically. (Video embedded below.)

The core problem was devising ways to sort, lift, place, and dump marbles in their correct positions without losing their marbles—figuratively and literally. Starting with color detection, [Engineezy] used an RGB color sensor and Euclidian math to determine each marble’s color. After trying several different mechanical sorting mechanisms, he settled on a solenoid and servo-actuated dump tube to drop the marble into the appropriate hopper.

After sorting, he faced challenges with designing a mechanism to transport marbles from the bottom hoppers to the top of the machine. While paddle wheels seemed promising at first, they tended to jam—a problem solved by innovating with Archimedes screws that move marbles up smoothly without clogs. The marbles are pushed into clear tubes on either side of the machine, providing a clear view of their parade to the top.

Perhaps most ingenious is his use of constant-force springs as a flexible funnel to guide the marbles to a moving slider that drops them into the correct column of the display. When a picture is complete, sliding doors open on the bottom of the columns, dumping the marbles into a chain lift which feeds them into the sorting section. Each of the mechanisms has a mirrored version of the other side, so the left and right halves of the display operate independently.

The final product is slow, satisfying and noisy kinetic testament to [Engineezy]’s perseverance through countless iterations and hiccups.

Marble machines can range from minimalist to ultra-complex musical monstrosities, but never fail to tickle our engineering minds. Continue reading “Automated Pixel Art With Marbles”

Why Electric Trains Sound The Way They Do

If you’re a seasoned international rail traveler you will no doubt have become used to the various sounds of electric locomotives and multiple units as they start up. If you know anything about electronics you’ll probably have made the connection between the sounds and their associated motor control schemes, but unless you’re a railway engineer the chances are you’ll still be in the dark about just what’s going on. To throw light on the matter, [Z&F Railways] have a video explaining the various control schemes and the technologies behind them.

It’s made in Scotland, so the featured trains are largely British or in particular Scottish ones, but since the same systems can be found internationally it’s the sounds which matter rather than the trains themselves. Particularly interesting is the explanation of PWM versus pattern mode, the latter being a series of symmetrical pulses at different frequencies to create the same effect as PWM, but without relying on a single switching frequency as PWM does. This allows the controller to more efficiently match its drive to the AC frequency demanded by the motor at a particular speed, and is responsible for the “gear change” sound of many electric trains. We’re particularly taken by the sound of some German and Austrian locomotives (made by our corporate overlords Siemens, by coincidence) that step through the patterns in a musical scale.

Not for the first time we’re left wondering why electric vehicle manufacturers have considered fake internal combustion noises to make their cars sound sporty, when the sound of true electrical power is right there. The video is below the break.

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Memristors Are Cool, Radiation-resistant Memristors Even Moreso

Space is a challenging environment for semiconductors, but researchers have shown that a specific type of memristor (the hafnium oxide memristor, to be exact) actually reacts quite usefully when exposed to gamma radiation. In fact, it’s even able to leverage this behavior as a way to measure radiation exposure. In essence, it’s able to act as both memory and a sensor.

Being able to resist radiation exposure is highly desirable for space applications. Efficient ways to measure radiation exposure are just as valuable. The hafnium oxide memristor looks like it might be able to do both, but before going into how that works, let’s take a moment for a memristor refresher.

A memristor is essentially two conductive plates between which bridges can be made by applying a voltage to “write” to the device, by which one sets it to a particular resistance. A positive voltage causes bridging to occur between the two ends, lowering the device’s resistance, and a negative voltage reverses the process, increasing the resistance. The exact formulation of a memristor can vary. The memristor was conceived in the 1970s by Leon Chua, and HP Labs created a working one in 2008. An (expensive) 16-pin DIP was first made available in 2015.

A hafnium oxide memristor is a bit different. Normally it would be write-once, meaning a negative voltage does not reset the device, but researchers discovered that exposing it to gamma radiation appears to weaken the bridging, allowing a negative voltage to reset the device as expected. Exposure to radiation also caused a higher voltage to be required to set the memristor; a behavior researchers were able to leverage into using the memristor to measure radiation exposure. Given time, a hafnium oxide memristor exposed to radiation, causing it to require higher-than-normal voltages to be “set”, eventually lost this attribute. After 30 days, the exposed memristors appeared to recover completely from the effects of radiation exposure and no longer required an elevated voltage for writing. This is the behavior the article refers to as “self-healing”.

The research paper has all the details, and it’s interesting to see new things relating to memristors. After all, when it comes to electronic components it’s been quite a long time since we’ve seen something genuinely new.