If you think about it, an antenna is nothing more than a radio frequency energy sensor, or — more precisely — a transducer. So, it shouldn’t be a surprise that there could be different ways to sense RF that would work as an antenna. A recent paper in Applied Physics Letters explains an atomic antenna comprised of a rubidium vapor cell.
The interesting thing is that the antenna has no electrical components in the antenna, and can be located far away from the actual receiver. Instead of coax cables, the signal is read with a laser.
There’s no point in denying it — if you’re a regular reader of Hackaday, you’ve almost certainly got a favorite chip. Some in the audience yearn for the simpler days of the 6502, while others spend their days hacking on modern microcontrollers like the ESP32 or RP2040. There are even some of you out there still reaching for the classic 555. Whatever your silicon poison, there’s a good chance the Macrochips project from [Jason Coon] has supersized it for you.
The original slate RP2040
The idea is simple: get a standard 100 mm x 100 mm (4″ x 4″) slate coaster, throw it in your laser engraver of choice, and zap it with a replica of a chip’s label. The laser turns the slate a light gray, which, when contrasted with the natural color of the slate, makes for a fairly close approximation of what the real thing looks like. To date, [Jason] has given more than 140 classic and modern chips the slate treatment. Though he’s only provided the SVGs for a handful of them, we’re pretty sure anyone with a laser at home will have the requisite skills to pull this off without any outside assistance.
The junk laser in question is a neodymium:YAG pulse laser that clearly has seen better days, both externally and internally. The original pistol-grip enclosure was essentially falling apart, but was superfluous to [Les]’ plans for the laser. Things were better inside the business end of the gun, at least in terms of having all the pieces in place, but the teardown still revealed issues. Chief among these was the gunk and grunge that had accumulated on the laser rod and the flash tube — [Les] blamed this on the previous owner’s use of tap water for cooling rather than deionized water. It was nothing a little elbow grease couldn’t take care of, though. Especially since the rest of the laser bits seemed in good shape, including the chromium:YAG Q-switch, which allows the lasing medium to build up a huge pulse of photons before releasing them in one gigantic pulse.
Cleaned up and with a few special modifications of his own, including a custom high-voltage power supply, [Les]’ laser was ready for tests. The results are impressive; peak optical power is just over a megawatt, which is enough power to have some real fun. We’ll be keen to see what he does with this laser — maybe blasting apart a CCD camera?
When researchers at the Galatea laboratory in Switzerland set out to create a femtosecond laser in glass they weren’t certain it was going to work. To be precise, their goal was to create a femtosecond laser cavity using carefully aligned optics. Rather than using the traditional, discrete method, they used a commercial femtosecond laser to carve out the elements of the optical cavity in glass. The choice for glass came down to the low thermal expansion of this material, and it being transparent for the optical frequencies being targeted.
Generic concept of an “all-glass” optical device, with the various stages of fabrication. (Credit: Antoine Delgoffe et al., 2023)
Even after using the existing laser to create the rough laser cavity, the resulting optical mirrors were not aligned properly, but this was all part of the plan.
By also adding slots that created a flexure mechanism, brief laser pulses could be used to gradually adjust the mirrors to create the perfect alignment. During subsequent testing of the newly created laser cavity it was found to be operating as expected. The original femtosecond laser had successfully created a new femtosecond laser.
Perhaps the most tantalizing aspect of this research is that this could enable much faster and ultimately cheaper production of such laser systems, especially once the tedious and currently completely manual mirror alignment procedure is automated. In addition, it raises the prospect of producing other types of optics including splitters and guides in a similar manner.
[Allen] was inspired by a TED talk from over a decade ago that involved targeting flying mosquitoes with high-powered scanning lasers. This technology never really came to fruition, and raised many questions about laser safety and effectiveness.
Testing the idea with only two mirrors installed.
This solution keeps the lasers, but goes a slightly different route — two 10-watt lasers bounced between multiple mirrors to create a laser death grid. It goes without saying that 10 watt lasers will blind you near instantly even at great range, and can burn skin and cause all manner of other horrors. Bouncing them around with mirrors and waving them about at mosquitoes is a really poor idea when even incidental exposure can do real harm.
Indeed, the laser is so powerful that it burns holes in the mirrors [Allen] used in early testing. It was around this time that [styropyro] was brought in to help ensure everyone involved got through the project with their eyesight intact.
[Allen]’s crew wears laser safety goggles when operating the horrifying handheld device, which mitigates some risk. The team also quickly notice beams escaping from various directions, due in part to the holes burned in their clothes. Electing to wrap the device in a heatproof blanket to avoid accidentally dazzling any nearby pilots was an obvious idea but turning the device off and destroying it would have been smarter.
Sadly, despite looking like the coolest cyberpunk weapon we’ve seen in years, the device doesn’t even kill mosquitoes very effectively. The bugs largely avoided the device, and only a few that flew directly into a beam ended up being cooked. The whole time watching the video, we feared someone dropping the rig, leading to a 10-watt beam bouncing off and striking some poor innocent bystander.
When you see the term cold fusion, you probably think about energy generation, but the Cold Metal Fusion Alliance is an industry group all about 3D printing metal using Selective Laser Sintering (SLS) printers. The technology promoted by Headmade Materials typically involves using a mix of metal and plastic powder. The resulting part is tougher than you might expect, allowing you to perform mechanical operations on it before it is oven-sintered to remove the plastic.
The key appears to be the patented powder, where each metal particle has a thin polymer coating. The low temperature of the laser in the SLS machine melts the polymer, binding the metal particles together. After printing, a chemical debinding system prepares the part — which takes twelve hours. Then, you need another twelve hours in the oven to get the actual metal part.
You might wonder why we are interested in this. After all, SLS printers are unusual — but not unheard of — in home labs. But we were looking at the latest offerings from Nexa3D and realized that the lasers in their low-end machines are not far from the lasers we have in our shops today. The QLS230, for example, operates at 30 watts. There’s plenty of people reading this that have cutters in that range or beyond out in the garage or basement.
We aren’t sure what a hobby setup would look like for the debinding and the oven steps, but it can’t be that hard. Maybe it is time to look at homebrew SLS printers again. Of course, the powder isn’t cheap and is probably hard to replace. We saw a 20 kg tub of it for the low price of €5,000. On the other hand, that’s a lot of powder, and it looks like whatever doesn’t go into your part can be reused so the price isn’t as bad as it sounds. We’d love to see someone get some of this and try it with a hacked printer.
We have seen homebrew SLS printers. There’s also OpenSLS that, coincidentally, uses a laser cutter. It wouldn’t be cheap or easy, but being able to turn out metal parts in your garage would be quite the payoff. Be sure to keep us posted on your progress.
Art is a funny thing. Sometimes, it’s best done in a one-off fashion and sold for a hugely inflated price. Othertimes, it’s more accessible, and it becomes desirable to sell it in great quantity. [Wesley Treat] has been doing just that, and he’s shared some of his tricks of the trade on YouTube.
The video concerns some retro-futuristic raygun artwork panels that [Wesley] made in a recent video. The panels proved mighty popular, which meant he had a new problem to contend with: how to make them in quantity. His initial process largely involved making them in a one-off fashion, and that simply wouldn’t scale.
[Wesley] starts right at the beginning, demonstrating first how he produces stacks of blanks for his art panels. For production scale, he used pre-painted matte aluminium panels to speed the process. It’s followed by a sanding step, before the panels go into a laser etching jig to get imprinted with [Wesley’s] maker’s mark. Panels are then drilled via CNC, etched with their front artwork, and then fitted with a front acrylic panel, similarly cut out on the laser cutter. Then it’s just a matter of packing and shipping, a logistical hurdle that many small businesses have had to overcome.
[Wesley] does a great job of examining what it takes to scale from building one of something to many. It’s a topic we’ve looked at a few times in the past. Video after the break.
