ManiPylator focusing its laser pointer at a page.

Simulation And Motion Planning For 6DOF Robotic Arm

[Leo Goldstien] recently got in touch to let us know about a fascinating update he posted on the Hackaday.io page for ManiPylator — his 3D printed Six degrees of freedom, or 6DOF robotic arm.

This latest installment gives us a glimpse at what’s involved for command and control of such a device, as what goes into simulation and testing. Much of the requisite mathematics is introduced, along with a long list of links to further reading. The whole solution is based entirely on free and open source (FOSS) software, in fact a giant stack of such software including planning and simulation software on top of glue like MQTT message queues.

The practical exercise for this installment was to have the arm trace out the shape of a heart, given as a mathematical equation expressed in Python code, and it fared quite well. Measurements were taken! Science was done!

We last brought you word about this project in October of 2024. Since then, the project name has changed from “ManiPilator” to “ManiPylator”. Originally the name was a reference to the Raspberry Pi, but now the focus is on the Python programming language. But all the bot’s best friends just call him “Manny”.

If you want to get started with your own 6DOF robotic arm, [Leo] has traced out a path for you to follow. We’d love to hear about what you come up with!

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Depositing Metal On Glass With Fiber Laser

Fiber lasers aren’t nearly as common as their diode and CO2 cousins, but if you’re lucky enough to have one in your garage or local makerspace, this technique for depositing thin films of metals in [Breaking Taps] video, embedded below, might be worth checking out. 

It’s a very simple hack: a metal shim or foil is sandwiched between two pieces of glass, and the laser is focused on the metal. Etching the foil blasts off enough metal to deposit a thin film of it onto the glass.  From electron microscopy, [Breaking Taps] reveals that what’s happening is that microscopic molten metal droplets are splashing up to the ̶m̶e̶t̶a̶l̶  glass, rather than this being any kind of plasma process like sputtering. He found this technique worked best with silver of all the materials tested, and there were a few. While copper worked, it was not terribly conductive — he suggests electroplating a thicker layer onto the (probably rather oxidized) copper before trying to solder, but demonstrates soldering to it regardless, which seems to work. 

This might be a neat way to make artistic glass-substrate PCBs. More testing will be needed to see if this would be worth the effort over just gluing copper foil to glass, as has been done before. [Breaking Taps] suspects, and we agree, that his process would work better under an inert atmosphere, and we’d like to see it tried.

One thing to note is that, regardless of atmosphere, alloys are a bit iffy with this technique, as the ‘blast little drops off’ process can cause them to demix on the glass surface. He also reasons that ‘printing’ a large area of metal onto the glass, and then etching it off would be a more reliable technique than trying to deposit complex patterns directly to the glass in one go. Either way, though, it’s worth a try if you have a fiber laser. 

Don’t have a fiber laser? Maybe you could build one. 

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Rusty bathtub outdoors on equally rusty car springs

Hot Rod Backyard Bath On Steel Spring Legs

In a fusion of scrapyard elegance and Aussie ingenuity, [Mark Makies] has given a piece of old steel a steamy second life with his ‘CastAway Tub’. Call it a bush mechanic’s fever dream turned functional sculpture, starring two vintage LandCruiser leaf springs, and a rust-hugged cast iron tub dug up after 20 years in hiding. And put your welding goggles on, because this one is equal parts brute force and artisan flair.

What makes this hack so bold is, first of all, the reuse of unforgiving spring steel. Leaf springs, notoriously temperamental to weld, are tamed here with oxy-LPG preheating, avoiding thermal shock like a pro. The tub sits proudly atop a custom-welded frame shaped from dismantled spring packs, with each leaf ground, clamped, torched, and welded into a steampunk sled base. The whole thing looks like it might outrun a dune buggy – and possibly bathe you while it’s at it. It’s a masterclass in metalwork with zero CAD, all intuition, and a grinder that’s seen things.

Inspired? For those with a secret love for hot water and hot steel, this build is a blueprint for turning bush junk into backyard art. Read up on the full build at Instructables.

Stamp breakout boards.

Stamp: Modular Breakout Boards For SMD Prototyping

[Kalesh Sasidharan] from Sciotronics wrote in to tell us about their project, Stamp: a modular set of template breakout boards designed to make prototyping with SMD components faster, easier, and more affordable. No breadboards, custom PCBs, or tangled jumper wires required. The project has blasted past its Kickstarter goal, and is on track to start shipping in September.

Stamp was created out of frustration with the traditional SMD prototyping workflow. Breadboards don’t support SMD parts directly, and using adapters quickly gets messy, especially when you need to iterate or modify a design. Ordering PCBs for every small revision just adds delay, and cost.

Stamp solves this by offering reusable template boards with commonly used SMD footprints. You place the main component on the front and the supporting components on the back. Many complete circuits, such as buck converters, sensor blocks, microcontrollers, and so on, can fit on a single 17.8 × 17.8 mm board.

Most Stamps feature custom castellated holes, designed for side-by-side or right-angle edge connections, enabling a modular, reconfigurable approach to circuit building. The plan is to make the designs fully open source, so that others can build or adapt them. Although many PCB manufacturers might not have the facilities to make the special castellated edges which are available on some Stamps.

Dave Jones from the EEVblog covered the Stamp on one of his recent Mailbag videos, which you can check out below. This isn’t the first time we’ve seen somebody promise to reinvent the breadboard, but we do appreciate the simplicity of this approach.

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Various hardware components laid out on a workbench.

Working On Open-Source High-Speed Ethernet Switch

Our hacker [Andrew Zonenberg] reports in on his open-source high-speed Ethernet switch. He hasn’t finished yet, but progress has been made.

If you were wondering what might be involved in a high-speed Ethernet switch implementation look no further. He’s been working on this project, on and off, since 2012. His design now includes a dizzying array of parts. [Andrew] managed to snag some XCKU5P FPGAs for cheap, paying two cents in the dollar, and having access to this fairly high-powered hardware affected the project’s direction.

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A white control box is shown in the foreground. The box has an LCD display, eight button, and two barbed fittings for flexible tubing.

Using Pitot Tubes For More Than Aircraft

When we hear the words “pitot tube,” we tend to think more of airplanes than of air ducts, but [Franci Kopač]’s guide to pitot tubes for makers shows that they can be a remarkably versatile tool for measuring air speed, even in domestic settings.

A pitot tube is a tube which faces into an air flow, with one hole at the front of the tube, and one on the side. It’s then possible to determine the air speed by measuring the pressure difference between the side opening and the end facing into the wind. At speeds, temperatures, and altitudes that a hacker’s likely to encounter (i.e. not on an airplane), the pressure difference is pretty small, and it’s only since the advent of MEMS pressure sensors that pitot tubes became practical for amateurs.

[Franci]’s design is based on a Sensiron SDP differential pressure sensor, a 3D-printed pitot tube structure, some tubing, and the microcontroller of your choice. It’s important to position the tube well, so that it doesn’t experience airflow disturbances from other structures and faces straight into the air flow. Besides good positioning, the airspeed calculation requires you to know the air temperature and absolute pressure.

[Franci] also describes a more exotic averaging pitot tube, a fairly simple variation which measures air speed in cavities more accurately. He notes that this provides a more inexpensive way of measuring air flow in ducts than air conditioning flow sensors, while being more resilient than propeller-based solutions – he himself used pitot tubes to balance air flow in his home’s ventilation. All of the necessary CAD files and Arduino code are available on his GitHub repository.

If you’re looking for a more conventional duct flow meter, we’ve covered one before. We’ve even seen a teardown of a pitot tube sensor system from a military drone.

Two rings of magnets are shown encasing a circular channel in a white plastic piece. The channel is filled with liquid metal, and a loop of wire is about to be lowered into the metal.

Magnetohydrodynamic Motors To Spin Satellites

Almost all satellites have some kind of thrusters aboard, but they tend to use them as little as possible to conserve chemical fuel. Reaction wheels are one way to make orientation adjustments without running the thrusters, and [Zachary Tong]’s liquid metal reaction wheel greatly simplifies the conventional design.

Reaction wheels are basically flywheels. When a spacecraft spins one, conservation of angular momentum means that the wheel applies an equal and opposite torque to the spacecraft, letting the spacecraft orient itself. The liquid-metal reaction wheel uses this same principle, but uses a loop of liquid metal instead of a wheel, and uses a magnetohydrodynamic drive to propel the metal around the loop.

[Zach] built two reaction wheels using Galinstan as their liquid metal, which avoided the toxicity of a more obvious liquid metal. Unfortunately, the oxide skin that Galinstan forms did make it harder to visualize the metal’s motion. He managed to get some good video, but a clearer test was their ability to produce torque. Both iterations produced a noticeable response when hung from a string and activated, and achieved somewhat better results when mounted on a 3D-printed air bearing.

Currently, efficiency is the main limitation of [Zach]’s motors: he estimates that the second model produced 6.2 milli-newton meters of torque, but at the cost of drawing 22 watts. The liquid metal is highly conductive, so the magnetohydrodynamic drive takes high current at low voltage, which is inconvenient for a spacecraft to supply. Nevertheless, considering how hard it is to create reliable, long-lasting reaction wheels the conventional way, the greatly improved resilience of liquid-metal reaction wheels might eventually be worthwhile.

If you’re curious for a deeper look at magnetohydrodynamic drives, we’ve covered them before. We’ve also seen [Zach]’s earlier experiments with Galinstan.

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