Slider

4774 Articles

Microfluidic Motors Could Work Really Well For Tiny Scale Tasks

November 14, 2024 by 8 Comments

The vast majority of motors that we care about all stick to a theme. They rely on the electromagnetic dance between electrons and magnets to create motion. They come in all shapes and sizes and types, but fundamentally, they all rely on electromagnetic principles at heart.

And yet! This is not the only way to create a motor. Electrostatic motors exist, for example, only they’re not very good because electrostatic forces are so weak by comparison. Only, a game-changing motor technology might have found a way to leverage them for more performance. It achieves this by working with fluid physics on a very small scale.

Continue reading “Microfluidic Motors Could Work Really Well For Tiny Scale Tasks” →

Retrotechtacular: The TV Bombs Of WWII

November 14, 2024 by 41 Comments

Anyone who was around for the various wars and conflicts of the early 2000s probably recalls the video clips showing guided bombs finding their targets. The black-and-white clips came from TV cameras mounted in the nose of the bomb, and were used by bombardiers to visually guide the warhead to the target — often providing for a level of precision amounting to a choice of “this window or that window?” It was scary stuff, especially when you thought about what was on the other side of the window.

Surprisingly, television-guide munitions aren’t exactly new, as this video on TV-guided glide bombs in WWII indicates. According to [WWII US Bombers], research on TV guidance by the US Army Air Force started in 1943, and consisted of a plywood airframe built around a standard 2000-pound class gravity bomb. The airframe had stubby wings for lift and steerable rudders and elevators for pitch and yaw control. Underneath the warhead was a boxy fairing containing a television camera based on an iconoscope or image orthicon, while all the radio gear rode behind the warhead in the empennage. A B-17 bomber could carry two GB-4s on external hardpoints, with a bulky TV receiver provided for the bombardier to watch the bomb’s terminal glide and make fine adjustments with a joystick.

In testing, the GB-4 performed remarkably well. In an era when a good bombardier was expected to drop a bomb in a circle with a radius of about 1,200′ (365 meters) from the aim point, GB-4 operators were hitting within 200′ (60 meters). With results like that, the USAAF had high hopes for the GB-4, and ordered it into production. Sadly, though, the testing results were not replicated in combat. The USAAF’s 388th Bomber Group dropped a total of six GB-4s against four targets in the European Theater in 1944 with terrible results. The main problem reported was not being able to see the target due to reception problems, leaving the bombardiers to fly blind. In other cases, the bomb’s camera returned a picture but the contrast in the picture was so poor that steering the weapon to the target was impossible. On one unfortunate attack on a steel factory in Duren, Germany, the only building with enough contrast to serve as an aiming point was a church six miles from the target.

The GB-4’s battlefield service was short and inglorious, with most of the 1,200 packages delivered never being used. TV-guided bombs would have to wait for another war, and ironically it would be the postwar boom in consumer electronics and the explosion of TV into popular culture would move the technology along enough to make it possible.

Continue reading “Retrotechtacular: The TV Bombs Of WWII” →

The Life Cycle Of Nuclear Fission Fuel: From Stars To Burn-Up

November 14, 2024 by 48 Comments

Outdone only by nuclear fusion, the process of nuclear fission releases enormous amounts of energy. The ‘spicy rocks’ that are at the core of both natural and artificial fission reactors are generally composed of uranium-235 (U-235) along with other isotopes that may or may not play a role in the fission process. A very long time ago when the Earth was still very young, the ratio of fissile U-235 to fertile U-238 was sufficiently high that nuclear fission would spontaneously commence, as happened at what is now the Oklo region of Gabon.

Although natural decay of U-235 means that this is unlikely to happen again, we humans have learned to take uranium ore and start a controlled fission process in reactors, beginning in the 1940s. This can be done using natural uranium ore, or with enriched (i.e. higher U-235 levels) uranium. In a standard light-water reactor (LWR) a few percent of U-235 is used up this way, after which fission products, mostly minor actinides, begin to inhibit the fission process, and fresh fuel is inserted.

This spent fuel can then have these contaminants removed to create fresh fuel through reprocessing, but this is only one of the ways we have to extract most of the energy from uranium, thorium, and other actinides like plutonium. Although actinides like uranium and thorium are among the most abundant elements in the Earth’s crust and oceans, there are good reasons to not simply dig up fresh ore to refuel reactors with.

Continue reading “The Life Cycle Of Nuclear Fission Fuel: From Stars To Burn-Up” →

FLOSS Weekly Episode 809: Pi4J – Stable And Boring On The Raspberry Pi

November 13, 2024 by No comments

This week, Jonathan Bennett and David Ruggles chat with Frank Delporte about Pi4J, the friendly Java libraries for the Raspberry Pi, that expose GPIO, SPI, I2C and other IO interfaces. Why would anyone want to use Java for the Pi? And what’s changed since the project started? Listen to find out!

Continue reading “FLOSS Weekly Episode 809: Pi4J – Stable And Boring On The Raspberry Pi” →

Making Sense Of Real-Time Operating Systems In 2024

November 13, 2024 by 52 Comments

The best part about real-time OS (RTOS) availability in 2024 is that we developers are positively spoiled for choice, but as a corollary this also makes it a complete pain to determine what the optimal choice for a project is. Beyond simply opting for a safe choice like FreeRTOS for an MCU project and figuring out any implications later during the development process, it can pay off massively to invest some time up-front matching the project requirements with the features offered by these various RTOSes. A few years ago I wrote a primer on the various levels of ‘real-time’ and whether you may even just want to forego an RTOS at all and use a simple Big Loop™ & interrupt-based design.

With such design parameters in mind, we can then look more clearly at the available RTOS options available today, which is the focus of this article. Obviously it won’t be an exhaustive comparison, and especially projects like FreeRTOS have seen themselves customized to various degrees by manufacturers like ST Microelectronics and Espressif, among others. This also brings to the forefront less pleasant considerations, such as expected support levels, as illustrated by e.g. Microsoft’s Azure RTOS (formerly ThreadX) recently getting moved to the Eclipse Foundation as the Eclipse ThreadX open source project. On one hand this could make it a solid open-source licensed RTOS, or it could have been open sourced because Microsoft has moved on to something else and cleared out its cupboard.

Thus without further ado, let’s have a look at RTOSes in 2024 and which ones are worth considering, in my opinion.

Continue reading “Making Sense Of Real-Time Operating Systems In 2024” →

A Teletype By Any Other Name: The Early E-mail And Wordprocessor

November 13, 2024 by 40 Comments

Some brand names become the de facto name for the generic product. Xerox, for example. Or Velcro. Teletype was a trademark, but it has come to mean just about any teleprinter communicating with another teleprinter or a computer. The actual trademark belonged to The Teletype Corporation, part of Western Electric, which was, of course, part of AT&T. But there were many other companies that made teleprinters, some of which were very influential.

The teleprinter predates the computer by quite a bit. The original impetus for their development was to reduce the need for skilled telegraph operators. In addition, they found use as crude wordprocessors, although that term wouldn’t be used for quite some time.

Continue reading “A Teletype By Any Other Name: The Early E-mail And Wordprocessor” →

Retrotechtacular: Color TV

November 12, 2024 by 20 Comments

We have often wondered if people dreamed in black and white before the advent of photography. While color pictures eventually became the norm, black and white TV was common for many years. After all, a TV set was a big investment, so people didn’t run out and buy the latest TV every year. Even if you did buy a new or used TV, a black and white model was much less expensive and, for many years, some shows were in black and white anyway. RCA, of course, wanted you to buy a color set. [PeriscopeFilm] has a 1963 promotional film from RCA extolling the virtues of a color set. The video also shows something about how the sets were made, as you can see below.

We aren’t sure we’d have led with the idea that color could save your life in this context, but we have to salute the melodrama. There is a good bit of footage of picture tube manufacturing, although the technical detail is — understandably — aimed at the general public.

Continue reading “Retrotechtacular: Color TV” →