3D Printing And The Dream Of Affordable Prosthetics

December 1, 2025 by 1 Comment

As amazing as the human body is, it’s unfortunately not as amazing as e.g. axolotl bodies are, in the sense that they can regrow entire limbs and more. This has left us humans with the necessity to craft artificial replacement limbs to restore some semblance of the original functionality, at least until regenerative medicine reaches maturity.

Despite this limitation, humans have become very adept at crafting prosthetic limbs, starting with fairly basic prosthetics to fully articulated and beautifully sculpted ones, all the way to modern-day functional prosthetics. Yet as was the case a hundred years ago, today’s prosthetics are anything but cheap. This is mostly due to the customization  required as no person’s injury is the same.

When the era of 3D printing arrived earlier this century, it was regularly claimed that this would make cheap, fully custom prosthetics a reality. Unfortunately this hasn’t happened, for a variety of reasons. This raises the question of whether 3D printing can at all play a significant role in making prosthetics more affordable, comfortable or functional.

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The New Pebble: Now 100% Open Source

December 1, 2025 by 2 Comments

The Pebble was the smartwatch darling of the early 2010s, a glimpse of the future in the form of a microcontroller and screen strapped to your wrist. It was snapped up by Fitbit and canned, which might have been the end of it all were it not for the dedication of the Pebble community. Google open-sourced the OS back in January this year, and since then a new set of Pebble products have appeared under the guidance of Pebble creator [Eric Migicovsky]. Now he’s announced the full open-sourcing of the current Pebble hardware and software stack. As he puts it, “Yesterday, Pebble watch software was ~95% open source. Today, it’s 100% open source”.

If you’re curious it can all be found in repositories under the Core Devices GitHub account. Building your own Pebble clone sounds cool, but perhaps the real value lies instead in giving the new Pebbles something the original never had, an assured future. If you buy one of the new watches then you’ll know that it will remain fixable, and since you have the full set of files you can create new parts for it, or update its software. We think that’s the right way to keep a personal electronic device relevant.

If you want a new Pebble they have a store, meanwhile read some of our previous coverage of its launch.

Sensor Package Aims To Predict Acid Rain

December 1, 2025 by 5 Comments

Acid rain sucks, particularly if you run a fancy university with lots of lovely statues outside. If you’d like to try and predict when it’s going to occur, you might like this project from [Mohammad Nihal].

When rain is particularly acidic, it’s usually because of the combination of sulfur dioxide or nitrogen dioxide and moisture in the atmosphere. This combination ends up making sulfuric acid or nitric acid that then falls to the ground as precipitation. The low-pH rain that results can harm ecosystems, melt statues, and just generally give everyone a hard time.

[Mohammed] decided to try and predict acid rain by building a simple device based on an Arduino Nano. It records SO2 levels with an MQ-136 gas sensor, and NO2 levels with an unspecified MEMS-based sensor. There’s also a DHT11 temperature & humidity sensor in the mix, which is important since moisture content plays a role. The Arduino reads these sensors and uses a simple predictive algorithm to create an “Acid Rain Risk Score” that is displayed on a 16×2 character LCD. It’s all wrapped up in a fun 3D printed enclosure that looks like a cloud.

There are some limitations to the device. Namely, it doesn’t necessarily have a great read on atmospheric SO2 and NO2 levels in the atmosphere, particularly at altitudes where rain is formed, because the sensor sits inside the device indoors. However, the basic concept is there, and improvements could certainly be made with some upgrades and further research.

All Handheld Antennas Are Not Born The Same

November 30, 2025 by 5 Comments

If you own a handheld transceiver of any type then the chances are it will come with a “rubber duck” style antenna. These flexible rubber-coated antennas are a compromise in performance, being significantly smaller than a wavelength at their frequency of operation. [OM40ET] has an interesting video in which he investigates this by tearing down a cheap rubber duck antenna and an even cheaper fake.

These antennas usually have a flexible upper section and a bulge at the bottom over the connector. The fake one has nothing in the bulge except the antenna wire and thus has a very high SWR, while the “real” one has a loading coil. This coil is an interesting design, because it’s designed such that the antenna has two resonant points at the 2 metre and 70 centimetre amateur bands. On paper it’s a tapped coil fed at the tap through a capacitor for matching, but a more detailed appraisal will tell you that the two halves of the coil are designed to return those two resonances. It’s still a not-very-good antenna, but the fact that it works at all is something.

If you want something better at VHF and haven’t got much space, all is not lost. We recently featured a VHF magnetic loop.

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[Piers] explains his code

A Deep Dive Into Using PIO And DMA On The RP2350

November 30, 2025 by 2 Comments

Here’s a fun rabbit hole to run down if you don’t already have the RP2040/RP2350 PIO feather in your cap: how to serve data without CPU intervention using PIO and DMA on the RP2350.

If you don’t know much about the RP2040 or RP2350 here’s the basic run down: the original Raspberry Pi Pico was released in 2021 with the RP2040 at its heart, with the RP2350 making its debut in 2024 with the Pico 2. Both microcontrollers include a feature known as Programmed I/O (PIO), which lets you configure tiny state machines and other facilities (shift registers, scratch registers, FIFO buffers, etc) to process simple I/O logic, freeing up the CPU to do other tasks.

The bottom line is that you can write very simple programs to do very fast and efficient I/O and these programs can run separately to the other code running on your micro. In the video below, [piers] explains how it works and how he’s used it in his One ROM project.

This is the latest installment from [piers rocks] whose One ROM project we’ve been tracking since July this year when we first heard about it. Since then we’ve been watching this project grow up and we were there when it was only implemented on the STM32F4, when it was renamed to One ROM, and when it got its USB stack. Along the way [piers rocks] was on FLOSS Weekly Episode 850: One ROM To Rule Them All too.

Have you seen PIO being put to good use in other projects? Let us know in the comments, or on the tips line!

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Jerry Seinfeld dressed up as a honey bee promoting his film Bee Movie.

Retrotechtacular: The $550K Video Conferencing System Used To Make Bee Movie

November 30, 2025 by 7 Comments

The modern office environment has shifted in recent years. Employees are routinely asked to collaborate with co-workers half way around the globe and be camera ready, or whatever passes for webcam ready, in order to telecommute when they are out of office. Every office laptop, tablet, or cell phone these days comes equipped with some sort of camera sensor capable of recording at HD resolution. Twenty years ago, that was not the case. Though tech conglomerates like HP had a different idea of teleconferencing to sell back in 2005 dubbed the Halo Collaboration Studio.

The Halo Studio was a collaboration between HP and Dreamworks that was used during the production of Bee Movie. Studio heads at Dreamworks thought it necessary to install the HP teleconferencing solution inside the New York office of Jerry Seinfeld, the writer of the film, as to allow him to avoid long trips to Dreamworks production offices in Los Angeles. According to the HP Halo Collaboration Studio brochure, “Halo actually pays for itself, not only by reducing travel costs, but also by encouraging higher productivity and stronger employee loyalty.” Certainly Dreamworks believed in that sales pitch for Bee Movie, because the upfront asking price left a bit of a sting.

Less of a singular machine, more of an entire dedicated room, the Halo Studio had a $550,000 asking price. It utilized three 1280×960 resolution plasma screens each fitted with a 720p broadcast camera and even included an “executive” table for six. The room lighting solution was also part of the package as the intent was to have all participants appear true to life size on the monitors. The system ran on a dedicated T3 fiber optic connection rated at 45 Mbps that connected to the proprietary Halo Video Exchange Network that gave customers access to 24×7 tech support for the small sum of $30,000 a month.

For more Retrotechtacular stories, check out Dan’s post on the Surveyor 1 documentary. It’s out of this world.

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Tiny Little TV Runs On ESP32

November 30, 2025 by 9 Comments

Few of us keep big old cathode ray tubes in the house anymore, but we can still appreciate the form factor of the classic TV. Indeed, the Tinytron from [t0mg] is a neat little tchotchke in this vein — a miniature TV that you could just about fit on a keyring.

[t0mg] wanted this project to be quick and easy to put together. It starts with an ESP32-S3-LCD-1.69 from Waveshare. It’s an all-in-one dev module which combines the microcontroller with a small screen right out of the box. You just have to solder a single six pin header to hook it up with an SD card reader and battery, and you’re done with the electronics. Even the case is a cinch to build, with four 3D printed components that can be spat out of a Prusa MK4S in just half an hour. Programming it can be done via a web browser. Just about the only thing it’s missing is a speaker — this TV is video only.

To watch things on the Tinytron, you just have to prepare them properly and drop them on the SD card. [t0mg] provides a web page for transcoding the video files, although you can do it yourself locally with ffmpeg if you prefer.

If you’re looking for a silly gift for a TV-obsessed friend, you could probably whip up a Tinytron in a couple hours or less. It reminds us of another great project, the tiny Simpsons replica TV that endlessly plays the greatest cartoon on Earth.

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