Isolated AC/DC Power Supply and Testing Station for 230 V Devices

When you’re testing or debugging some mains-powered gear, plugging it directly into the outlet can often be an exciting proposition. If such excitement is not really your thing, you can opt for an isolation transformer and other types of safeties. In the case of [Michał Słomkowski], he opted to take a few steps further by modding a vintage East-German isolating variac with a broken amp meter into an isolated AC/DC power supply and testing station.

The core is formed by the isolated variable transformer, to which a configurable DC output section, a current limiter and digital voltage and current read-outs were...

Environmental Monitoring on the Cheap

If there is one thing we took from [azwankhairul345’s] environmental monitor project, it is this: sensors and computing power for such a project are a solved problem. What’s left is how to package it. The solution, in this case, was using recycled plastic containers, and it looks surprisingly effective.

A Raspberry Pi Pico W has the processing capability and connectivity for a project like this. A large power bank battery provides the power. Off-the-shelf sensors for magnetic field (to measure anemometer spins), air quality, temperature, and humidity are easy to acquire. The plastic tub that protects everything also has PVC pipe...

FOSDEM 2026 schedule – Embedded, RISC-V, Robotics, Rust, Open Hardware, and more

FOSDEM 2026 will take place on January 31-February 1, with thousands of developers meeting in Brussels to discuss open-source software & hardware projects. The free-to-attend “Free and Open Source Software Developers’ European Meeting” gets more traction every year, and in 2026, there will be at least 1,113 speakers, 1,016 events, 70 tracks, and potentially close to 10,000 attendees. As usual, I’ll create a virtual schedule with sessions most relevant to the topics covered on CNX Software from the “Embedded, Mobile and Automotive” and “Open Hardware and CAD/CAM” devrooms, but also other devrooms, including “RISC-V”, “Robotics and simulation”, and “FOSS on...

Beer Keg Plumbing for a Liquid Rocket

https://invidious.privacyredirect.com/watch?v=TzWWWmHvjkI

When you think of a high performance liquid rocket, what do you think of? Beer kegs? No? Well, when [Ryan] from the YouTube channel “Project KegRocket” saw a beer keg, the first thing he and his friends saw was a pressurized rocket body.

You wouldn’t be crazy if the first thing you thought of was something designed by a massive company or university. Liquid rockets are far from simple to develop, with Keg Rocket being no exception. Liquid oxygen and alcohol is the oxidizer/fuel mixture of choice. Liquid oxygen in particular is a problem with its cryogenic temperatures and tendency to...

Polymer Skins That Change Color and Texture When Exposed to Water

Researchers at Stanford University recently came up with an interesting way (Phys.org summary) to create patterns and colors that emerge when a polymer is exposed to water. Although the paper itself is sadly paywalled with no preprint available, it’s fairly easily summarized and illustrated with details from the Supplementary Data section. The polymer used is poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), which when exposed to an electron beam (electron-beam lithography) undergoes certain changes that become apparent when said water is added.

The polymer is hygroscopic, but the electron beam modifies the extent to which a specific area swells up, thus making it possible...

Innodisk Releases EXEC-Q911 Development Kit with Qualcomm QCS9075

Innodisk, in collaboration with Qualcomm Technologies, has released the EXEC-Q911, a ruggedized development kit built around a COM-HPC Mini module mounted on a dedicated carrier board for industrial edge workloads. Part of the company’s “AI on Dragonwing” series, the platform targets robotics, smart infrastructure, and edge LLM applications. The compatible COM-HPC Mini Module EXMP-Q911 is […]

Lead Acid Battery Upgraded to Lithium Iron Phosphate

https://invidious.privacyredirect.com/watch?v=l-nkiqVb0J8

Lithium batteries have taken over as the primary battery chemistry from applications ranging from consumer electronics to electric vehicles and all kinds of other things in between. But the standard lithium ion battery has a few downsides, namely issues operating at temperature extremes. Lead acid solves some of these problems but has much lower energy density, and if you want to split the difference with your own battery you’ll need to build your own lithium iron phosphate (LiFePO4) pack.

[Well Done Tips] is building this specific type of battery because the lead acid battery in his electric ATV is on the...

PLA Mold To Plaster Bust, No Silicone Needed

https://invidious.privacyredirect.com/watch?v=2j9BSms_avc

3D printing is wonderful, but sometimes you just don’t want to look at a plastic peice. Beethoven’s bust wouldn’t look quite right in front of your secret door if it was bright orange PLA, after all. [Denny] over at “Shake the Future” on YouTube is taking a break from metal casting to show off a quick-and-easy plaster casting method— but don’t worry, he still uses a microwave.

Most people, when they’re casting something non-metallic from a 3D print are going to reach for castable silicone and create a mold, first. It works for chocolate just as easily as it does plaster,...

Wired to Wireless: ESP32 Gives Your USB Keyboard Bluetooth

https://invidious.privacyredirect.com/watch?v=dVUMYTfJw0s

Few things rival the usability and speed of a full-sized keyboard for text input. For decades, though, keyboards were mostly wired, which can limit where you use your favorite one. To address this, [KoStard]’s latest project uses an ESP32 to bridge a USB keyboard to BLE devices.

The ESP32-S3 packs a ton of fantastic functionality into its small size and low price—including USB-OTG support, which is key here. Taking advantage of this, [KoStard] programmed an ESP32-S3 to host a keyboard over its USB port while connecting via BLE to devices like cellphones.

There are some slick tricks baked in,...

Notes on the Intel 8086 processor's arithmetic-logic unit

In 1978, Intel introduced the 8086 processor, a revolutionary chip that led to the modern x86 architecture. Unlike modern 64-bit processors, however, the 8086 is a 16-bit chip. Its arithmetic/logic unit (ALU) operates on 16-bit values, performing arithmetic operations such as addition and subtraction, as well as logic operations including bitwise AND, OR, and XOR. The 8086's ALU is a complicated part of the chip, performing 28 operations in total.1

In this post, I discuss the circuitry that controls the ALU, generating the appropriate control signals for a particular operation. The process is more complicated than you might expect. First, a machine code instruction results in the...