A Laser With Mirrors Makes A CRT-like Display

November 26, 2024 by 22 Comments

[bitluni]’s laser-based display pretending to be a an old-school vector CRT.
Phosphor-based displays like CRTs rely on the phosphor to emit light for a set amount of time after being activated, allowing them to display a seemingly persistent image with one drawing beam per color. Translated to UV-sensitive PLA filament, this means that you can totally use a printed sheet of this material in combination with a 405 nm laser diode to create a display that doesn’t look dissimilar to an early CRT. This is exactly what [bitluni] did in a recent video, meshing together said laser diode, UV-sensitive PLA, stepper motors and two mirrors with an Arduino-based controller to create a rather interesting vector display.

In the video, [bitluni] goes over the development steps, including a range of improvements like being able to turn off the laser when moving between the end of a line and the beginning of a new one. While the Arduino Nano board does the driving of the stepper motor controllers, an ESP32 provides the drawing instructions. The STL and other project files including Nano & ESP32 firmware can be found on the GitHub project page.

While far from being a practical display with a single-digit Hz refresh rate, it does provide an interesting demonstration of these types of persistence of vision based displays, and without the use of exotic MEMS mirror modules or the like.

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Alternatives Don’t Need To Be Bashed

November 26, 2024 by 20 Comments

By default, bash is the most popular command language simply because it’s included in most *nix operating systems. Additionally, people don’t tend to spend a lot of time thinking about whatever their computer uses for scripting as they might for other pieces of software like a word processor or browser. If you are so inclined to take a closer look at this tool that’s often taken for granted, there are a number of alternatives to bash and [monzool] wanted to investigate them closely.

Unlike other similar documentation that [monzool] has come across where the writers didn’t actually use the scripting languages being investigated, [monzool] is planning to use each of these and accomplish specific objectives. This will allow them to get a feel for the languages and whether or not they are acceptable alternatives for bash. Moving through directories, passing commands back and forth, manipulating strings, searching for files, and manipulating the terminal display settings are all included in this task list. A few languages are tossed out before initial testing even begins for not meeting certain specific requirements. One example is not being particularly useful in [monzool]’s preferred embedded environments, but even so there are enough bash alternatives to test out ten separate languages.

Unfortunately, at the end of the day none of the ten selected would make a true replacement for bash, at least for [monzool]’s use case, but there were a few standouts nonetheless. Nutshell was interesting for being a more modern, advanced system and [monzool] found Janet to be a fun and interesting project but had limitations with cross-compiling. All in all though this seemed to be an enjoyable experience that we’d recommend if you actually want to get into the weeds on what scripting languages are actually capable of. Another interesting one we featured a while back attempts to perform as a shell and a programming language simultaneously.

Linux Fu: Audio Network Pipes

November 26, 2024 by 18 Comments

Life was simpler when everything your computer did was text-based. It is easy enough to shove data into one end of a pipe and take it out of the other. Sure, if the pipe extends across the network, you might have to call it a socket and take some special care. But how do you pipe all the data we care about these days? In particular, I found I wanted to transport audio from the output of one program to the input of another. Like most things in Linux, there are many ways you can get this done and — like most things in Linux — only some of those ways will work depending on your setup.

Why?

There are many reasons you might want to take an audio output and process it through a program that expects audio input. In my case, it was ham radio software. I’ve been working on making it possible to operate my station remotely. If all you want to do is talk, it is easy to find software that will connect you over the network.

However, if you want to do digital modes like PSK31, RTTY, or FT8, you may have a problem. The software to handle those modes all expect audio from a soundcard. They also want to send audio to a soundcard. But, in this case, the data is coming from a program.

Of course, one answer is to remote desktop into the computer directly connected to the radio. However, most remote desktop solutions aren’t made for high-fidelity and low-latency audio. Plus, it is nice to have apps running directly on your computer.

I’ll talk about how I’ve remoted my station in a future post, but for right now, just assume we want to get a program’s audio output into another program’s audio input. Continue reading “Linux Fu: Audio Network Pipes” →

Recreating Unobtainium Weather Station Sensors

November 26, 2024 by 20 Comments

Imagine you own a weather station. Then imagine that after some years have passed, you’ve had to replace one of the sensors multiple times. Your new problem is that the sensor is no longer available. What does a hacker like [Luca] do? Build a custom solution, of course!

[Luca]’s work concerns the La Crosse WS-9257F-IT weather station, and the repeat failures of the TX44DTH-IT external sensor. Thankfully, [Luca] found that the weather station’s communication protocol had been thoroughly reverse-engineered by [Fred], among others. He then set about creating a bridge to take humidity and temperature data from Zigbee sensors hooked up to his Home Assistant hub, and send it to the La Crosse weather station. This was achieved with the aid of a SX1276 LoRa module on a TTGO LoRa board. Details are on GitHub for the curious.

Luca didn’t just work on the Home Assistant integration, though. A standalone sensor was also developed, based on the Xiao SAMD21 microcontroller board and a BME280 temperature, pressure, and humidity sensor. It too can integrate with the Lacrosse weather station, and proved useful for one of [Luca’s] friends who was in the same boat.

Ultimately, it sucks when a manufacturer no longer supports hardware that you love and use every day. However, the hacking community has a way of working around such trifling limitations. It’s something to be proud of—as the corporate world leaves hardware behind, the hackers pick up the slack!

Humans Can Learn Echolocation Too

November 26, 2024 by 50 Comments

Most of us associate echolocation with bats. These amazing creatures are able to chirp at frequencies beyond the limit of our hearing, and they use the reflected sound to map the world around them. It’s the perfect technology for navigating pitch-dark cave systems, so it’s understandable why evolution drove down this innovative path.

Humans, on the other hand, have far more limited hearing, and we’re not great chirpers, either. And yet, it turns out we can learn this remarkable skill, too. In fact, research suggests it’s far more achievable than you might think—for the sighted and vision impaired alike!

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The Junk Machine Prints Corrupted Advertising On Demand

November 26, 2024 by 13 Comments

[ClownVamp]’s art project The Junk Machine is an interactive and eye-catching machine that, on demand, prints out an equally eye-catching and unique yet completely meaningless (one may even say corrupted) AI-generated advertisement for nothing in particular.

The machine is an artistic statement on how powerful software tools that have genuine promise and usefulness to creative types are finding their way into marketer’s hands, and resulting in a deluge of, well, junk. This machine simplifies and magnifies that in a physical way.

We can’t help but think that The Junk Machine is in a way highlighting Sturgeon’s Law (paraphrased as ‘ninety percent of everything is crud’) which happens to be particularly applicable to the current AI landscape. In short, the ease of use of these tools means that crud is also being effortlessly generated at an unprecedented scale, swamping any positive elements.

As for the hardware and software, we’re very interested in what’s inside. Unfortunately there’s no deep technical details, but the broad strokes are that The Junk Machine uses an embedded NVIDIA Jetson loaded up with Stable Diffusion’s SDXL Turbo, an open source AI image generator that can be installed and run locally. When and if a user mashes a large red button, the machine generates a piece of AI junk mail in real time without any need for a network connection of any kind, and prints it from an embedded printer.

Watch it in action in the video embedded below, just under the page break. There are a few more different photos on [ClownVamp]’s X account.

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Electric Motors Run Continuously At Near-Peak Power

November 26, 2024 by 35 Comments

For a lot of electrical and mechanical machines, there are nominal and peak ratings for energy output or input. If you’re in marketing or advertising, you’ll typically look at the peak rating and move on with your day. But engineers need to know that most things can only operate long term at a fraction of this peak rating, whether it’s a power supply in a computer, a controller on an ebike, or the converter on a wind turbine. But this electric motor system has a unique cooling setup allowing it to function at nearly full peak rating for an unlimited amount of time.

The motor, called the Super Continuous Torque motor built by German automotive manufacturer Mahle is capable of 92% of its peak output power thanks to a unique oil cooling system which is able to remove heat and a rapid rate. Heat is the major limiter for machines like this; typically when operating at a peak rating a motor would need to reduce power output to cool down so that major components don’t start melting or otherwise failing. Given that the largest of these motors have output power ratings of around 700 horsepower, that’s quite an impressive benchmark.

The motor is meant for use in passenger vehicles but also tractor-trailer style trucks, where a motor able to operate at its peak rating would mean a smaller size motor or less weight or both, making them easier to fit into the space available as well as being more economically viable. Mahle is reporting that these motors are ready for production so we should be seeing them help ease the transportation industry into electrification. If you’re more concerned about range than output power, though, there’s a solution there as well so you don’t have to be stuck behind the times with fossil fuels forever.

Thanks to [john] for the tip!