Upgraded Raster Laser Projector Goes RGB

September 18, 2024 by No comments

We’ve covered a scanning laser project by Ben Make’s Everything last year, and now he’s back with a significant update. [Ben]’s latest project now offers a higher resolution and RGB lasers. A couple of previous versions of the device used the same concept of a rotating segmented mirror synchronised to a pulsed laser diode to create scanlines. When projected onto a suitable surface, the distorted, pixelated characters looked quite funky, but there was clearly room for improvement.

More scanlines and a faster horizontal pixel rate

The previous device used slightly inclined mirrors to deflect the beam into scanlines, with one mirror per scanline limiting the vertical resolution. To improve resolution, the mirrors were replaced with identically aligned mirrors of the type used in laser printers for horizontal scanning. An off-the-shelf laser galvo was used for vertical scanning, allowing faster scanning due to its small deflection angle. This setup is quicker than then usual vector galvo application, as the smaller movements require less time to complete. Once the resolution improvement was in hand, the controller upgrade to a Teensy 4 gave more processing bandwidth than the previous Arduino and a consequent massive improvement in image clarity.

Finally, monochrome displays don’t look anywhere near as good as an RGB setup. [Ben] utilised a dedicated RGB laser setup since he had trouble sourcing the appropriate dichroic mirrors to match available lasers. This used four lasers (with two red ones) and the correct dichroic mirrors to combine each laser source into a single beam path, which was then sent to the galvo. [Ben] tried to find a DAC solution fast enough to drive the lasers for a proper colour-mixing input but ended up shelving that idea for now and sticking with direct on-off control. This resulted in a palette of just seven colours, but that’s still a lot better than monochrome.

The project’s execution is excellent, and care was taken to make it operate outdoors with a battery. Even with appropriate safety measures, you don’t really want to play with high-intensity lasers around the house!

Here’s the previous version we covered, a neat DIY laser galvo using steppers, and a much older but very cool RGB vector projector.

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FLOSS Weekly Episode 801: JBang — Not Your Parents Java Anymore

September 18, 2024 by 1 Comment

This week Jonathan Bennett and Jeff Massie chat with Max Rydahl Andersen about JBang, the cross-platform tool to run Java as a system scripting language. That’s a bit harder than it sounds, particularly to take advantage of Java’s rich debugging capabilities and the ecosystem of libraries that are available. Tune in to get the details, as well as how polyglot files are instrumental to making JBang work!

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Catching The BOAT: Gamma-Ray Bursts And The Brightest Of All Time

September 18, 2024 by 11 Comments

Down here at the bottom of our ocean of air, it’s easy to get complacent about the hazards our universe presents. We feel safe from the dangers of the vacuum of space, where radiation sizzles and rocks whizz around. In the same way that a catfish doesn’t much care what’s going on above the surface of his pond, so too are we content that our atmosphere will deflect, absorb, or incinerate just about anything that space throws our way.

Or will it? We all know that there are things out there in the solar system that are more than capable of wiping us out, and every day holds a non-zero chance that we’ll take the same ride the dinosaurs took 65 million years ago. But if that’s not enough to get you going, now we have to worry about gamma-ray bursts, searing blasts of energy crossing half the universe to arrive here and dump unimaginable amounts of energy on us, enough to not only be measurable by sensitive instruments in space but also to effect systems here on the ground, and in some cases, to physically alter our atmosphere.

Gamma-ray bursts are equal parts fascinating physics and terrifying science fiction. Here’s a look at the science behind them and the engineering that goes into detecting and studying them.

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Bringing The Horror Of Seaman Into The Real World

September 18, 2024 by 11 Comments

A little under 25 years ago, a particularly bizarre game was released for Sega’s Dreamcast. In actually, calling it a “game” might be something of a stretch. It was more of a pet simulator, where you need to feed and care for a virtual animal as it grows. Except rather than something like a dog or a rabbit, your pet is a talking fish with a human face that doesn’t seem to like you very much. Oh, and Leonard Nimoy is there too for some reason.

Most people in the world don’t even know this game ever existed, and frankly, their lives are all the better for it. But for those who lovingly cared for (or intentionally killed) one of these rude creatures back in the early 2000s, it’s an experience that sticks with you. Which we assume is why [Robert Prest] decided to build this incredibly faithful physical recreation of Seaman. 

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Ferrites Versus Ethernet In The Ham Shack

September 17, 2024 by 29 Comments

For as useful as computers are in the modern ham shack, they also tend to be a strong source of unwanted radio frequency interference. Common wisdom says applying a few ferrite beads to things like Ethernet cables will help, but does that really work?

It surely appears to, for the most part at least, according to experiments done by [Ham Radio DX]. With a particular interest in lowering the noise floor for operations in the 2-meter band, his test setup consisted of a NanoVNA and a simple chunk of wire standing in for the twisted-pair conductors inside an Ethernet cable. The NanoVNA was set to sweep across the entire HF band and up into the VHF; various styles of ferrite were then added to the conductor and the frequency response observed. Simply clamping a single ferrite on the wire helped a little, with marginal improvement seen by adding one or two more ferrites. A much more dramatic improvement was seen by looping the conductor back through the ferrite for an additional turn, with diminishing returns at higher frequencies as more turns were added. The best performance seemed to come from two ferrites with two turns each, which gave 17 dB of suppression across the tested bandwidth.

The question then becomes: How do the ferrites affect Ethernet performance? [Ham Radio DX] tested that too, and it looks like good news there. Using a 30-meter-long Cat 5 cable and testing file transfer speed with iPerf, he found no measurable effect on throughput no matter what ferrites he added to the cable. In fact, some ferrites actually seemed to boost the file transfer speed slightly.

Ferrite beads for RFI suppression are nothing new, of course, but it’s nice to see a real-world test that tells you both how and where to apply them. The fact that you won’t be borking your connection is nice to know, too. Then again, maybe it’s not your Ethernet that’s causing the problem, in which case maybe you’ll need a little help from a thunderstorm to track down the issue. Continue reading “Ferrites Versus Ethernet In The Ham Shack” →

Latest PiEEG Shield Now Offers 16 Channels

September 17, 2024 by 23 Comments

We’ve previously covered the PiEEG, an affordable brain-computer interface (BCI) shield designed to connect to the Raspberry Pi. The open source project developed by [Ildar Rakhmatulin] is intended to allow students and hobbyists to experiment with detecting electroencephalography (EEG), electromyography (EMG), and electrocardiography (ECG) biosignals — unlocking a wide array of applications ranging from assistive tech to gaming.

Now, the PiEEG hardware has been upgraded to detect sixteen channels via either wet or dry electrodes. The new board, referred to as the PiEEG-16, offers up the same ease of use and features as its predecessor, including the ability to read out signals from the device using Python scripts. Compared to the eight channels supported by the previous generation of hardware, the PiEEG-16 promises to provide the fine-grain data required for more complex operations.

Since we last checked in with the PiEEG back in 2023, [Ildar] says the project has attracted plenty of attention. To help document how the community is using the capability offered by these BCIs, he’s added a page on the project’s site to show off what folks are building with the technology.

Inevitably, some express concern when talking about non-professionals working with brain interfacing hardware. But the project’s documentation is quick to point out that efforts have been taken to make the endeavour as risk-free as possible. The most important thing to remember is that the Raspberry Pi and PiEEG are intended to be powered by batteries so as to remain completely isolated. Similarly, there’s no need to connect the devices to a mains-powered computer, as everything happens on the Pi itself.

Even still, it’s made clear that the PiEEG-16 is not a medical device, and has received no formal certifications. If you want to experiment with this technology, you do so at your own risk. Just something to keep in mind…no pun intended.

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New DuckyPad Pro Is Bigger And Smarter Than Original

September 17, 2024 by 3 Comments

In a world that has no shortage of macropads, the duckyPad still managed to set itself apart. The open source mechanical pad offered an incredible array of customization options, and thanks to its onboard OLED display, you never had to wonder which key did what. But there’s always room for improvement.

Announced earlier today, the duckyPad Pro is the culmination of everything creator [dekuNukem] learned from developing, marketing, and supporting the original duckyPad. Much hasn’t changed — it looks largely the same, offers the same RGB-backlit mechanical switches, and the trademark OLED is still there, although it’s gotten a little larger. The obvious changes are the addition of five more keys, and a pair of rotary encoders.

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