Building An Eight Channel Active Mixer

June 3, 2025 by 29 Comments

There are plenty of audio mixers on the market, and the vast majority all look the same. If you wanted something different, or just a nice learning experience, you could craft your own instead. That’s precisely what [Something Physical] did. 

The build was inspired by an earlier 3-channel mixer designed by [Moritz Klein]. This project stretches to eight channels, which is nice, because somehow it feels right that a mixer’s total channels always land on a multiple of four. As you might expect, the internals are fairly straightforward—it’s just about lacing together all the separate op-amp gain stages, pots, and jacks, as well as a power LED so you can tell when it’s switched on. It’s all wrapped up in a slant-faced wooden box with an aluminum face plate and Dymo labels. Old-school, functional, and fit for purpose.

It’s a simple build, but a satisfying one; there’s something beautiful about recording on audio gear you’ve hewn yourself. Once you’ve built your mixer, you might like to experiment in the weird world of no-input mixing. Video after the break.

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Open Source Watch Movement Really Ticks All The Boxes

June 3, 2025 by 32 Comments

When you think of open-source hardware, you probably think of electronics and maker tools– RepRap, Arduino, Adafruit, et cetera. Yet open source is an ethos and license, and is in no way limited to electronics. The openmovement foundation is a case in point– a watch case, to be specific. The “movement” in Openmovement is a fully open-source and fully mechanical watch movement.

Openmovement has already released STEP files of OM10 the first movement developed by the group. (You do need to sign up to download, however.) They say the design is meant to be highly serviceable and modular, with a robust construction suited for schools and new watchmakers. The movement uses a “Swiss pallets escapement” that runs at 3.5 Hz / 25,200 vph. (We think that’s an odd translation of lever escapement, but if you’re a watchmaker let us know in the comments.)  An OM20 is apparently in the works, as well, but it looks like only OM10 has been built from what we can see.

If you don’t have the equipment to finely machine brass from the STEP files, Openmovement is running a crowdfunding campaign to produce kits of the OM10, which you can still get in on until the seventh of June.

If you’re wondering what it takes to make a mechanical watch from scratch, we covered that last year. Spoiler: it doesn’t look easy. Just assembling the tiny parts of an OM10 kit would seem daunting to most of us. That might be why most of the watches we’ve covered over the years weren’t mechanical, but at least they tend to be open source, too.

3D Printed Tank Has A Cannon To Boot

June 3, 2025 by 7 Comments

Few of us will ever find ourselves piloting a full-sized military tank. Instead, you might like to make do with the RC variety. [TRDB] has whipped up one of their own design which features a small little pellet cannon to boot.

The tank is assembled from 3D printed components — with PETG filament being used for most of the body and moving parts, while the grippy parts of the treads are printed in TPU. The tank’s gearboxes consist of printed herringbone gears, and are driven by a pair of powerful 775 brushed DC motors, which are cooled by small 40 mm PC case fans. A rather unique touch are the custom linear actuators, used to adjust the tank’s ride height and angle relative to the ground. The small cannon on top is a flywheel blaster that fires small plastic pellets loaded from a simple drum magazine. Running the show is an ESP32, which responds to commands from [TRDB]’s own custom RC controller built using the same microcontroller.

As far as DIY RC tanks go, this is a very complete build. We’ve seen some other great work in this space, like this giant human-sized version that’s big enough to ride in.

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Supercon 2024: How To Track Down Radio Transmissions

June 3, 2025 by 10 Comments

You turn the dial on your radio, and hear a powerful source of interference crackle in over the baseline noise. You’re interested as to where it might be coming from. You’re receiving it well, and the signal strength is strong, but is that because it’s close or just particularly powerful? What could it be? How would you even go about tracking it down?

When it comes to hunting down radio transmissions, Justin McAllister and Nick Foster have a great deal of experience in this regard. They came down to the 2024 Hackaday Superconference to show us how it’s done.

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ManiPylator focusing its laser pointer at a page.

Simulation And Motion Planning For 6DOF Robotic Arm

June 3, 2025 by 11 Comments

[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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My Winter Of ’99: The Year Of The Linux Desktop Is Always Next Year

June 3, 2025 by 229 Comments

Growing up as a kid in the 1990s was an almost magical time. We had the best game consoles, increasingly faster computers at a pace not seen before, the rise of the Internet and World Wide Web, as well the best fashion and styles possible between neon and pastel colors, translucent plastic and also this little thing called Windows 95 that’d take the world by storm.

Yet as great as Windows 95 and its successor Windows 98 were, you had to be one of the lucky folks who ended up with a stable Windows 9x installation. The prebuilt (Daewoo) Intel Celeron 400 rig with 64 MB SDRAM that I had splurged on with money earned from summer jobs was not one of those lucky systems, resulting in regular Windows reinstalls.

As a relatively nerdy individual, I was aware of this little community-built operating system called ‘Linux’, with the online forums and the Dutch PC magazine that I read convincing me that it would be a superior alternative to this unstable ‘M$’ Windows 98 SE mess that I was dealing with. Thus it was in the Year of the Linux Desktop (1999) that I went into a computer store and bought a boxed disc set of SuSE 6.3 with included manual.

Fast-forward to 2025, and Windows is installed on all my primary desktop systems, raising the question of what went wrong in ’99. Wasn’t Linux the future of desktop operating systems?

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Add Wood Grain Texture To 3D Prints – With A Model Of A Log

June 3, 2025 by 34 Comments

Adding textures is a great way to experiment with giving 3D prints a different look, and [PandaN] shows off a method of adding a wood grain effect in a way that’s easy to play around with. It involves using a 3D model of a log (complete with concentric tree rings) as a print modifier. The good news is that [PandaN] has already done the work of creating one, as well as showing how to use it.

The model of the stump — complete with concentric tree rings — acts as a modifier for the much-smaller printed object (in this case, a small plate).

In the slicer software one simply uses the log as a modifier for an object to be printed. When a 3D model is used as a modifier in this way, it means different print settings get applied everywhere the object to be printed and the modifier intersect one another.

In the case of this project, the modifier shifts the angle of the fill pattern wherever the models intersect. A fuzzy skin modifier is used as well, and the result is enough to give a wood grain appearance to the printed object. When printed with a wood filament (which is PLA mixed with wood particles), the result looks especially good.

We’ve seen a few different ways to add textures to 3D prints, including using Blender to modify model surfaces. Textures can enhance the look of a model, and are also a good way to hide layer lines.

In addition to the 3D models, [PandaN] provides a ready-to-go project for Bambu slicer with all the necessary settings already configured, so experimenting can be as simple as swapping the object to be printed with a new 3D model. Want to see that in action? Here’s a separate video demonstrating exactly that step-by-step, embedded below.

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