If you’re looking for a more open, unenclosed 3D printer design than a cubic frame can accommodate, but don’t want to use a bed-slinger, you don’t have many options. [Boothy Builds] recently found himself in this situation, so he designed the Hi5, a printer that holds its hotend between two cantilevered arms.

The hotend uses bearings to slide along the metal arms, which themselves run along linear rails. The most difficult part of the design was creating the coupling between the guides that slides along the arms. It had to be rigid enough to position the hotend accurately and repeatably, but also flexible enough avoid binding. The current design uses springs to tension the bearings, though [Boothy Builds] eventually intends to find a more elegant solution. Three independent rails support the print bed, which lets the printer make small alterations to the bed’s tilt, automatically tramming it. Earlier iterations used CNC-milled bed supports, but [Boothy Builds] found that 3D printed plastic supports did a better job of damping out vibrations.

[Boothy Builds] notes that the current design puts the X and Y belts under considerable load, which sometimes causes them to slip, leading to occasional layer shifts and noise in the print. He acknowledges that the design still has room for improvement, but the design seems quite promising to us.

This printer’s use of cantilevered arms to support the print head puts it in good company with another interesting printer we’ve seen. Of course, that design element does also lend itself to the very cheapest of printers.

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Thanks to [Keith Olson] for the tip!

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[Kevin Cheung] likes to upcycle old soda cans into — well — things. The metal is thin enough to cut by hand, but he’d started using a manual die-cutting machine, and it worked well. The problem? The machine was big and heavy, weighing well over 30 pounds. The solution was to get a lightweight die cutter. It worked better than expected, but [Kevin] really wanted it to be more portable, so he stripped it down and built the mechanism into a new case.

The video below isn’t quite a “how-to” video, but if you like watching someone handcraft something with a lot of skill, you’ll enjoy it. It also might give you ideas about how you could use one of these cutters, even if you don’t bother building a nice case for it.

We’ve seen cutters that use computer control, but they aren’t inexpensive. They will, however, make the same kind of cuts. But these manual die cutters are very inexpensive, and you simply have to find a way to make the die. You can easily make them for cutting paper, and, with the right materials, you can make the kind you see in [Kevin]’s video, too.

We have to admit, carrying the gizmo into a public place seemed to make a lot of people happy. So maybe portability is a good goal. But either way, you can have some fun with a machine like that.

If you want to cut paper, these work great. If you want paper to make the cuts, we have just the thing for you.

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hackaday.com/2025/07/12/die-cu…

Molto interessanti anche i commenti.

ilpost.it/2025/07/12/telefono-…

#fairphone #fairphone6

Un telefono più giusto

Gli smartphone prodotti da Fairphone sono riparabili e costruiti con materie prime estratte in modo più responsabile, e hanno un loro piccolo mercato

^{Il Post}

Display technology has come a long way since the advent of the CRT in the late 1800s (yes, really!). Since then, we’ve enjoyed the Nixie tubes, flip dots, gas plasma, LCD, LED, ePaper, the list goes on. Now, there’s a new kid on the block — water.

[Steve Mould] recently got his hands on an OpenDrop — an open-source digital microfluidics platform for biology research. It’s essentially a grid of electrodes coated in a dielectric. Water sits atop this insulating layer, and due to its polarized nature, droplets can be moved around the grid by voltages applied to the electrodes. The original intent was to automate experiments (see 8:19 in the video below for some wild examples), but [Steve] had far more important uses in mind.

When [Steve]’s €1,000 device shipped from Switzerland, it was destined for greatness. It was turned into a game console for classics such as Pac-Man, Frogger, and of course, Snake. With help from the OpenDrop’s inventor (and Copilot), he built paired-down versions of the games that could run on the 8×14 “pixel” grid. Pac-Man in particular proved difficult, because due to the conservation of mass, whenever Pac-Man ate a ghost, he grew and eventually became unwieldy. Fortunately, Snake is one of the few videogames that actually respects the laws of classical mechanics, as the snake grows by one unit each time it consumes food.

[Steve] has also issued a challenge — if you code up another game, he’ll run it on his OpenDrop. He’s even offering a prize for the first working Tetris implementation, so be sure to check out his source code linked in the video description as a starting point. We’ve seen Tetris on oscilloscopes and 3D LED matrices before, so it’s about time we get a watery implementation.

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Thanks to [deʃhipu] for the tip!

hackaday.com/2025/07/12/playin…

If you’ve worked with germanium transistors, you’ll know that many of them have a disappointingly low maximum frequency of operation. This has more to do with some of the popular ones dating from the earliest years of the transistor age than it does to germanium being inherently a low frequency semiconductor, but it’s fair to say you won’t be using an OC71 in a high frequency RF application. It’s clear that [Ken Yap]’s project is taking no chances though, because he’s using a vintage germanium transistor at a very low frequency — 1 Hz, to be exact.

The circuit is a simple enough phase shift oscillator that flashes a white LED, in which a two transistor amplifier feeds back on itself through an RC phase shift network. The germanium part is a CV7001, while the other transistor is more modern but still pretty old these days silicon part, a BC109. The phase shift network has a higher value resistor than you might expect at 1.8 MOhms, because of the low frequency of operation. Power meanwhile comes from a pair of AA cells.

We like this project not least for its use of very period passive components and stripboard to accompany the vintage semiconductor parts. Perhaps it won’t met atomic standards for timing, but that’s hardly the point.

This project is an entry in the 2025 One Hertz Challenge. Why not enter your own second-accurate project?

hackaday.com/2025/07/12/2025-o…

Penso che fare una donazione sia importante, prima di tutto per portare un minimo di sollievo ai palestinesi ma anche perché su quei 30 euro che doniamo ci scriviamo che il mondo non è tutto Trump, Meloni e compagnia bella, che ci siamo anche noi. E credo che loro riescano a leggerlo.

E da ultimo serve anche a noi, per la soddisfazione che dà sentirsi dalla parte giusta in un mondo che sembra correre a rompicollo nella direzione sbagliata.

unponteper.it/it/campagna/acqu…

There are many ways to learn, but few to none of them compare to that of spending time standing over the shoulder of a master of the craft. This awesome page sent in by [JohnU] is a fantastic corner of the internet that lets us all peek over that shoulder to see someone who’s not only spent decades learning the art of of creating cable harnesses, but has taken the time to distill some of that vast experience for the rest of us to benefit from.

This page is focused on custom automotive and motorcycle modifications, but it’s absolutely jam-packed with things applicable in so many areas. It points out how often automotive wiring is somewhat taken for granted, but it shouldn’t be; there are hundreds of lines, all of which need to work for your car to run in hot and cold, wet and dry. The reliability of wiring is crucial not just for your car, but much larger things such as the 530 km (330 mi) of wiring inside an Airbus A380 which, while a large plane, is still well under 100 m in length.

This page doesn’t just talk about cable harnessing in the abstract; in fact, the overwhelming majority of it revolves around the practical and applicable. There is a deep dive into wiring selection, tubing and sealing selection, epoxy to stop corrosion, and more. It touches on many of the most common connectors used in vehicles, as well as connectors not commonly used in the automotive industry but that possess many of the same qualities. There are some real hidden gems in the midst of the 20,000+ word compendium, such as thermocouple wiring and some budget environmental sealing options.

There is far more to making a thing beyond selecting the right parts; how it’s assembled and the tools used are just as important. This page touches on tooling, technique, and planning for a wire harness build-up. While there are some highly specialized tools identified, there are also things such as re-purposed knitting needles. Once a harness is fully assembled it’s not complete, as there is also a need for testing that must take place which is also touched on here.

Thanks to [JohnU] for sending in this incredible learning resource. If this has captured your attention like it has ours, be sure to check out some of the other wire harness tips we’ve featured!

hackaday.com/2025/07/12/wire-l…

Sixteen Israeli experts in international law warned in a public letter that the plans presented by Israel's defense minister to concentrate Gaza's population in a "humanitarian city" constitute a manifestly illegal order and a war crime.

us18.campaign-archive.com/?e=0…