Learn 15 Print-in-Place Mechanisms In 15 Minutes

3D printed in-place mechanisms and flexures, such as living hinges, are really neat when you can get them to print correctly. But how do you actually do that? YouTuber [Slant 3D] is here with a helpful video demonstrating the different kinds of springs and hinges (Video, embedded below) that can be printed reliably, and discusses some common pitfalls and areas to concentrate upon.

Living hinges are everywhere and have been used at least as long as humans have been around. The principle is simple enough; join two sections to move with a thinned section of material that, in small sections, is flexible enough to distort a few times without breaking off. The key section is “a few times”, as all materials will eventually fail due to overworking. However, if this thing is just a cheap plastic case around a low-cost product, that may not be a huge concern. The video shows a few ways to extend flexibility, such as spreading the bending load across multiple flexure elements to reduce the wear of individual parts, but that comes at the cost of compactness.

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Exploring The RP2350’s UART-Bootloader

The RP2350 has a few advantages over its predecessor, one of which is the ability to load firmware remotely via UART, as [Thomas Pfister] has documented on his blog and in the video below.

[Thomas] had a project that needed more PWM than the RP2350 could provide, and hit upon the idea of using a second RP2350 as a port expander. Now, one could hard-code this, but dealing with two sets of firmware on one board can be annoying. That’s where the UART bootloader comes in: it will allow [Thomas] to program the port-expander RP2350 using the main microcontroller. Thus he only has to worry about one firmware, speeding up development.

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Tearing Down A Forgotten Video Game

Remember Video Volley? No? We don’t either. It looks like it was a very early video game console that could play tennis, hockey, or handball. In this video, [James] tears one apart. If you are like us, we are guessing there will be little more than one of those General Instrument video game chips inside.

These don’t look like they were mass-produced. The case looks like something off the shelf from those days. The whole thing looks more like a nice homebrew project or a pretty good prototype. Not like something you’d buy in a store.

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boxie player

Boxie – A Gameboy-Esque Audio Player

This little audiobook player is a stellar example of the learning process behind a multifaceted project blending mechanical, electrical, and software design. [Mario] designed this audiobook player, dubbed Boxie, for his 3-year-old son to replace the often-used but flawed Toniebox.

The inspiration for Boxie was the Toniebox, a kid-friendly audiobook player. While functional, the Toniebox had drawbacks: it required internet connectivity, limited media selection, and had unreliable controls. Enter Boxie, a custom-built, standalone audiobook player free from web services, designed to address these issues with superior audio quality and toddler-friendly controls.

Boxie’s media is stored on microSD cards inserted into a slot on the device. To make this manageable for a toddler, he designed a PCB with a standard microSD card interface, ensuring easy swapping of audiobooks. The enclosure, crafted via 3D printing, is durable and compact, tailored for small hands.

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Another Old ThinkPad Gets A New Motherboard

The Thinkpad line of laptops, originally from IBM, and then from Lenovo, have long been the choice of many in our community. They offer a level of robustness and reliability missing in many cheaper machines. You may not be surprised to find that this article is being written on one. With such a following, it’s not surprising that a significant effort has gone into upgrading older models. For example, we have [Franck Deng]’s new motherboard for the Thinkpad X200 and X201. These models from the end of the 2000s shipped as far as we can remember with Core 2 Duo processors, so we can imagine they would be starting to feel their age.

It’s fair to say the new board isn’t a cheap option, but it does come with a new Core Ultra 7 CPU, DDR5 memory, M.2 interfaces for SSDs alongside the original 2.5″ device, and USB-C with Thunderbolt support. There are a range of screen upgrade options. For an even more hefty price, you can buy a completely rebuilt laptop featuring the new board. We’re impressed with the work, but we have to wonder how it would stack up against a newer Thinkpad for the price.

If you’re curious to see more of the same, this isn’t the first such upgrade we’ve seen.

Thanks [Max] for the tip.

An LLM For The Raspberry Pi

Microsoft’s latest Phi4 LLM has 14 billion parameters that require about 11 GB of storage. Can you run it on a Raspberry Pi? Get serious. However, the Phi4-mini-reasoning model is a cut-down version with “only” 3.8 billion parameters that requires 3.2 GB. That’s more realistic and, in a recent video, [Gary Explains] tells you how to add this LLM to your Raspberry Pi arsenal.

The version [Gary] uses has four-bit quantization and, as you might expect, the performance isn’t going to be stellar. If you are versed in all the LLM lingo, the quantization is the way weights are stored, and, in general, the more parameters a model uses, the more things it can figure out.

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Restoring A Sinclair C5 For The Road

The Sinclair C5 was Sir Clive’s famous first venture into electric mobility, a recumbent electric-assisted tricycle which would have been hardly unusual in 2025. In 1985, though, the C5 was so far out there that it became a notorious failure. The C5 retains a huge following among enthusiasts, though, and among those is [JSON Alexander, who has bought one and restored it.

We’re treated to a teardown and frank examination of the vehicle’s strengths and weaknesses, during which we see the Sinclair brand unusually on a set of tyres, and the original motor, which is surprisingly more efficient than expected. Sir Clive may be gone, but this C5 will live again.

We’ve had the chance to road test a C5 in the past, and it’s fair to say that we can understand why such a low-down riding position was not a success back in the day. It’s unusual to see one in as original a condition as this one, it’s more usual to see a C5 that’s had a few upgrades.