In this series of 23 YouTube videos [Rich] puts the AMD Zynq-7000 SoC through its paces by building a development board from the ground up to host it along with its peripherals. The Zynq is part FPGA and part CPU, and while it has been around for a while, we don’t see nearly as many projects about it as we’d like.
[Rich] covers everything from the power system to HDMI, USB, DDR RAM, and everything in between. By the end, he’s able to boot PetaLinux.
S4 slicer uses the path from any point (here, Benchy’s prow) as its basis…
This non-planar slicer is built into a Jupyter notebook, which follows a relatively simple algorithm to automatically generate non-planar toolpaths for any model. It does this by first generating a tetrahedral mesh of the model and then calculating the shortest possible path through the model from any given tetrahedron to the print bed. Even with non-planar printing, you need to print from the print-bed up (or out).
Quite a lot of math is done to use these paths to calculate a deformation mesh, and we’ll leave that to [Joshua] to explain in his video below. After applying the deformation, he slices the resulting mesh in Cura, before the G-code goes back to Jupyter to be re-transformed, restoring the shape of the original mesh.
… to generate deformed models for slicing, like this.
So yes, it is G-code bending as others have demonstrated before, but in a reproducible, streamlined, and straightforward workflow. Indeed, [Josh] credits much of the work to earlier work on the S^3-Slicer, which inspired much of the logic and the name behind his S4 slicer. (Not S4 as in “more than S^3” but S4 as a contraction of “Simplified S^3”). Once again, open source allows for incremental innovation.
It is admittedly a computationally intensive process, and [Joshua] uses a simplified model of Benchy for this demo. This seems exactly the sort of thing we’d like to burn compute power on, though.
It’s traditional to launch new software on April Fool’s Day, which is when we heard that Rockbox 4.0 has been released. But, in this case, the venerable MP3 firmware actually did update after a long absence. It’s great to see that good old Rockbox is still kicking along. We first mentioned Rockbox here at Hackaday approaching 20 years ago. How time flies. There used to be a whole ‘scene’ around hacking Personal Media Players (PMPs), also known as “MP3 Players”.
We tracked down Rockbox contributor [Solomon Peachy] to ask for some simple advice: If someone wants to install Rockbox on a personal media player today, what hardware should they buy? [Solomon] referred us to the AIGO EROS Q / EROS K, which is the only compatible hardware still being manufactured and sold. Beyond that, if you want to buy compatible hardware, you’ll need to find some secondhand somewhere, such as eBay. See the Rockbox Wiki for supported hardware.
Smartphones and streaming services have subsumed the single-purpose personal media player. Will you put the new Rockbox on something? Let us know in the comments.
The user interface of things we deal with often makes or breaks our enjoyment of using a device. [Janne] thinks so, he has an espresso machine he enjoys but the default controls were not what he was looking for and so in true hacker fashion he took what was and made it his own.
Although uranium-235 is the typical fuel for commercial fission reactors on account of it being fissile, it’s relatively rare relative to the fertile U-238 and thorium (Th-232). Using either of these fertile isotopes to breed new fuel from is thus an attractive proposition. Despite this, only India and China have a strong focus on using Th-232 for reactors, the former using breeders (Th-232 to U-233) to create fertile uranium fuel. China has demonstrated its approach — including refueling a live reactor — using a fourth-generation molten salt reactor.
In 1977, a little way outside of Seattle, Washington Nuclear Projects 3 and 5 (WNP-3 and WNP-5) were started as part of Washington Public Power Supply System (WPPSS, pronounced “whoops”). They ran over budget, and in the 80s they were mothballed even though WNP-3 was nearly complete.
There are two key design decisions that make the HydraJet what it is. First, she chose to propel the boat by pushing against the air via an electric ducted fan (EDF) rather than the water via a traditional water propeller. This simplified construction and made it more affordable, partly because she already had the fan on hand.
Her other design choice was to use wings underneath the boat to lift it out of the water. Not as hydrofoils, where the wings ride below the surface of the water, but for hydroplaning where the wings ride on the surface of the water. Lifting the vehicle out of the water, of course, reduces drag, improving performance as we’ve often seen with high speed watercraft (including RC models) as well as slower bicycle-powered ones. The choice to rely on hydroplaning also reduces the complexity of the design. Certain hydrofoil designs need to make adjustments in order to keep the vehicle at a steady level, whereas a hydroplaning wings can use a static angle. Hydrofoils also must overcome challenges to maintain stability.
[CovaConcepts] hopes to eventually scale the HydraJet up large enough to carry human passengers and we’re looking forward to the opportunity to take it for a spin around the lake.
![Benchy, printed upside down on [Josh's] Core R-Theta printer.](https://hackaday.com/wp-content/uploads/2025/04/upside-down-benchy-nonplaner-e1745086286623.jpg?w=600&h=450)
