In A World Without USB…

February 19, 2025 by 26 Comments

It is easy to forget that many technology juggernauts weren’t always the only game in town. Ethernet seems ubiquitous today, but it had to fight past several competing standards. VHS and Blu-ray beat out their respective competitors. But what about USB? Sure, it was off to a rocky start in the beginning, but what was the real competition at that time? SCSI? Firewire? While those had plusses and minuses, neither were really in a position to fill the gap that USB would inhabit. But [Ernie Smith] remembers ACCESS.bus (or, sometimes, A.b) — what you might be using today if USB hadn’t taken over the world.

Back in the mid-1980s, there were several competing serial bus systems including Apple Desktop Bus and some other brand-specific things from companies like Commodore (the IEC bus) and Atari (SIO). The problem is that all of these things belong to one company. If you wanted to make, say, keyboards, this was terrible. Your Apple keyboard didn’t fit your Atari or your IBM computer. But there was a very robust serial protocol already in use — one you’ve probably used yourself. IIC or I2C (depending on who you ask).

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MIT Demonstrates Fully 3D Printed, Active Electronic Components

February 19, 2025 by 26 Comments

One can 3D print with conductive filament, and therefore plausibly create passive components like resistors. But what about active components, which typically require semiconductors? Researchers at MIT demonstrate working concepts for a resettable fuse and logic gates, completely 3D printed and semiconductor-free.

Now just to be absolutely clear — these are still just proofs of concept. To say they are big and perform poorly compared to their semiconductor equivalents would be an understatement. But they do work, and they are 100% 3D printed active electronic components, using commercially-available filament.

How does one make a working resettable fuse and transistor out of such stuff? By harnessing thermal expansion, essentially.

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Belfry OpenSCAD Library (BOSL2) Brings Useful Parts And Tools Aplenty

February 18, 2025 by 16 Comments

OpenSCAD has a lot of fans around these parts — if you’re unaware, it’s essentially a code-based way of designing 3D models. Instead of drawing them up in a CAD program, one writes a script that defines the required geometry. All that is made a little easier with the Belfry OpenSCAD Library (BOSL2).

Designing a part like this is a cinch with BOSL2.

BOSL2 has an extensive library of base shapes, advanced functions for manipulating models, and some really nifty tools for creating attachment points on parts and aligning components with one another. If that sounds handy for designing useful objects, you’re in for even more of a treat when you see their functions for gears, hinges, screws, and more.

There’s even one that covers bottle necks and caps. (Those are all standardized by the way, so it’s never been easier to interface to existing bottles or caps in a project.)

OpenSCAD really is very versatile software. It powers useful tools like this screw, washer, and nut generator as well as having more unusual applications like a procedural terrain generator. It’s free, so if you’ve never looked into it, check it out!

Vacuum Forming With 3D Printed Moulds And Sheets

February 18, 2025 by 12 Comments

Vacuum forming is perhaps one of the less popular tools in the modern maker arsenal, something which surprises us a bit because it offers many possibilities. We’ve created our own vacuum forms on 3D printed moulds for ages, so it’s interesting to see [Pisces Printing] following the same path. But what you might not realize at first is that the vacuum forming sheets themselves are also 3D printed.

The full video is below the break, and in it he details making a mould from PETG, and in particular designing it for easy release. The part he’s making is a belt guard for a table top lathe, and the PETG sheet he’s forming it from is also 3D printed. He makes the point that it’s by no means perfect, for example he shows us a bit of layer separation, but it seems promising enough for further experimentation.  His vacuum forming setup seems particularly small, which looks as though it makes the job of making a sheet somewhat simpler.

The cost of a vacuum forming sheet of whichever polymer is hardly high, so we can’t see this technique making sense for everyday use. But as we’ve seen in previous experiments, the printed sheets so make it easy to add color and texture to the final product, which obviously adds some value to the technique.

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A Unique Linear Position Sensor Using Magnetostriction

February 18, 2025 by 16 Comments

To the extent that you’re familiar with magnetostriction, you probably know that it’s what makes big transformers hum, or that it’s what tips you off if you happen to walk out of a store without paying for something. But magnetostriction has other uses, too, such as in this clever linear position sensor.

Magnetostriction is just the tendency for magnetic materials to change size or shape slightly while undergoing magnetization, thanks to the tiny magnetic domains shifting within the material while they’re aligning. [Florian B.]’s sensor uses a side effect of magnetostriction known as the Wiedenmann effect, which causes a wire to experience a twisting force if a current pulse is applied to it in a magnetic field. When the current pulse is turned off, a mechanical wave travels along the wire to a coil, creating a signal. The difference in time between sending the pulse and receiving the reflection can be used to calculate the position of the magnet along the wire.

To turn that principle into a practical linear sensor, [Florian B.] used nickel wire stretched tightly down the middle of a PVC tube. At one end is a coil of copper magnet wire, while the other end has a damper to prevent reflections. Around the tube is a ring-shaped cursor magnet, which can move up and down the tube. An exciter circuit applies the current pulse to the wire, and an oscilloscope is used to receive the signal from the wire.

This project still appears to be in the prototype phase, as evidenced by the Fischertechnik test rig. [Florian] has been working on the exciter circuit most recently, but he’s done quite a bit of work on optimizing the cursor magnet and the coil configuration, as well as designs for the signal amplifier. It’s a pretty neat project, and we’re looking forward to updates.

If you need a deeper dive into magnetostriction, [Ben Krasnow] points the way.

A black and white image of a dark framed e-reader with a keyboard below its e-ink screen. It is on a piece of cloth.

Auto-Download Your Kindle Books Before February 26th Deadline

February 18, 2025 by 85 Comments

With the news that Amazon will no longer be allowing users to download their Kindle books after February 26th, many are scrambling to download their books before it’s too late. The most up-to-date project for automating this process appears to be Amazon Kindle Bulk Downloader.

As the company that famously removed 1984 from thousands of devices without users permission, this is a move that shouldn’t be surprising, but is still disappointing, especially for those of us that were somewhat early adopters of ebooks with Kindles that don’t have a WiFi connection. (Yes, you can tell us about how you bought a Sony reader before the Kindle even came out in the comments.)

The Typescript-coded tool runs inside bun which can be installed in any of the big three OSes and even has a handy Docker image if that’s more your speed. Whether you use this tool or not, if you have any Kindle books we’d implore you to download them now.

Once you’ve downloaded those books, how about cracking the DRM either with LEGO or with software like Calibre. You could load it on a completely Open Source Reader then.

Close up of a custom optical HDMI cable on a desk

Let There Be Light: The Engineering Of Optical HDMI

February 18, 2025 by 15 Comments

In a recent video, [Shahriar] from The Signal Path has unveiled the intricate design and architecture of optical HDMI cables, offering a cost-effective solution to extend HDMI 2.0 connections beyond the limitations of traditional copper links. This exploration is particularly captivating for those passionate about innovative hardware hacks and signal transmission technologies.

[Shahriar] begins by dissecting the fundamentals of HDMI high-speed data transmission, focusing on the Transition Minimized Differential Signaling (TMDS) standard. He then transitions to the challenges of converting from twisted-pair copper to optical lanes, emphasizing the pivotal roles of Vertical-Cavity Surface-Emitting Lasers (VCSELs) and PIN photodiodes. These components are essential for transforming electrical signals into optical ones and vice versa, enabling data transmission over greater distances without significant signal degradation.

A standout aspect of this teardown is the detailed examination of the optical modules, highlighting the use of free-space optics and optical confinement techniques with lasers and detectors. [Shahriar] captures the eye diagram of the received high-speed lane and confirms the VCSELs’ optical wavelength at 850 nm. Additionally, he provides a microscopic inspection of the TX and RX chips, revealing the intricate VCSEL and photodetector arrays. His thorough analysis offers invaluable insights into the electronic architecture of optical HDMI cables, shedding light on the complexities of signal integrity and the innovative solutions employed to overcome them.

For enthusiasts eager to take a deeper look into the nuances of optical HDMI technology, [Shahriar]’s comprehensive teardown serves as an excellent resource. It not only gives an insight in the components and design choices involved, but also inspires further exploration into enhancing data transmission methods.

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