Hackaday Links: November 18, 2018

November 18, 2018 by Brian Benchoff 18 Comments

The greatest bit of consumer electronics is shipping and the reviews are out: Amazon’s Alexa-enabled microwave is a capable microwave, but befuddling to the voice-controlled-everything neophyte. Voice controlled everything is the last hope we have for technological innovation; it’s the last gasp of the consumer electronics industry. This is Amazon’s first thing with a built-in voice assistant, and while this is a marginally capable microwave at only 700 Watts — fine for a college dorm, but it’s generally worth shelling out a bit more cash for a 1000 Watt unit — the controls are befuddling. The first iteration is always hard, and we’re looking forward to the Amazon Alexa-enabled toaster, toothbrush, vacuum cleaner, and Bezos shrine.

Need a laser cutter, like crowdfunding campaigns, and know literally nothing about laser cutters? Have we got something for you. The Etcher Laser crowdfunding campaign has been pinging my email non-stop, and they’ve got something remarkable: a diode laser ~~cutter~~ engraver for $500. It comes in a neat-looking enclosure, so it’s sure to raise a lot of money.

A while back [Paulusjacobus] released an Arduino-based CNC controller for K40 laser cutters. There were a few suggestions to upgrade this to the STM32, so now this CNC controller is running on a Blue Pill. Yes, it’s great and there’s more floating points and such and such, so now this project is a Kickstarter project. Need a CNC controller based on the STM32? Boom, you’re done. It’s also named the ‘Super Gerbil’, which is an awesome name for something that is effectively a GRBL controller. Naming things is the hardest problem in computer science, after all.

The Gigatron computer is a ‘home computer’ without a microprocessor or microcontroller. How does it do this? A metric butt-load of ROM and look-up tables. This is cool and all, but now the Gigatron logo is huge. we’re talking 18 μm by 24 μm. This was done by etching a silicon test wafer with electron beam lithography.

The How And Why Of Laser Cutter Aiming

November 9, 2018 by Tom Nardi 16 Comments

Laser aficionado [Martin Raynsford] has built up experience with various laser cutters over the years and felt he should write up a blog post detailing his first-hand findings with an often overlooked aspect of the machines: aiming them. Cheap diode laser cutters and engravers operate in the visible part of the spectrum, but when you get into more powerful carbon dioxide lasers such as the one used in the popular K40 machines, the infrared beam is invisible to the naked eye. A secondary low-power laser helps to visualize the main laser’s alignment without actually cutting the target. There are a couple of ways to install an aiming system like this, but which way works better?

[Martin] explains that there are basically two schools of thought: a head-mounted laser, or a beam combiner. In both cases, a small red diode laser (the kind used in laser pointers) is used to indicate where the primary laser will hit. This allows the user to see exactly what the laser cutter will do when activated, critically important if you’re doing something like engraving a device and only have one chance to get it right. Running a “simulation” with the red laser removes any doubt before firing up the primary laser.

That’s the idea, anyway. In his experience, both methods have their issues. Head-mounted lasers are easier to install and maintain, but their accuracy changes with movement of the machine’s Z-axis: as the head goes up and down, the red laser dot moves horizontally and quickly comes out of alignment. Using the beam combiner method should, in theory, be more accurate, but [Martin] notes he’s had quite a bit of trouble getting both the red and IR lasers to follow the same course through the machine’s mirrors. Not only is it tricky to adjust, but it’s also much more complex to implement and may even rob the laser of power due to the additional optics involved.

In the end, [Martin] doesn’t think there is really a clear winner. Neither method gives 100% accurate results, and both are finicky, though in different scenarios. He suggests you just use whatever method your laser cutter comes with from the factory, as trying to change it probably isn’t worth the effort. But if your machine doesn’t have anything currently, the head-mounted laser is certainly the easier one to retrofit.

In the past, we’ve covered a third and slightly unconventional way of aiming the K40, as well as a general primer for anyone looking to pick up eBay’s favorite laser cutter.

Vibrosight Hears When You Are Sleeping. It Knows When You’re Awake.

October 22, 2018 by Tom Nardi 16 Comments

No matter how excited you are to dive headfirst into the “Internet of Things”, you’ve got to admit that the effort and expense of going full-on Jetsons is a bit off-putting. To smarten up your home you’ve generally got to buy all new products (and hope they’re all compatible) or stick janky after-market sensors on the gear you’ve already got (and still hope they’re all compatible). But what if there was a cheap and easy way to keep tabs on all your existing stuff? The answer may lie in Cold War era surveillance technology.

As if the IoT wasn’t already Orwellian enough, Vibrosight is a project that leverages a classic KGB spy trick to keep tabs on what’s going on inside your home. Developed by [Yang Zhang], [Gierad Laput] and [Chris Harrison], the project uses retro-reflective stickers and a scanning laser to detect vibrations over a wide area. With this optical “stethoscope”, the system can glean all kinds of information; from how long you’ve been cooking something in the microwave to whether or not you washed your hands.

The project takes its inspiration from the optical eavesdropping system developed by Léon Theremin in the late 1940’s. By bouncing a beam of light off of a window, Theremin’s gadget was able to detect what people inside the room were saying from a distance. The same idea is applied here, except now it uses an automated laser scanner and machine learning to turn detected vibrations into useful information that can be plugged into a home automation system.

For Vibrosight to “listen” to objects, the user needs to place retro-reflective tags on whatever they want to include in the system. The laser will periodically scan around the room looking for these tags. Once the laser finds a new tag, will add it to a running list of targets to keeps an eye on. From there Vibrosight is able to take careful vibration measurements which can provide all sorts of information. In the video after the break, Vibrosight is shown differentiating between walking, jogging, and running on a treadmill and determining what kind of hand tools are being used on a workbench. The team even envisions a future where Vibrosight-ready devices would “hum” their IP address or other identifying information to make device setup easier.

If all this talk of remote espionage at a distance has caught your interest, we’ve covered Theremin’s unique surveillance creations in the past, and even a way to jam them if you’re trying to stay under the radar.

Continue reading “Vibrosight Hears When You Are Sleeping. It Knows When You’re Awake.” →

This Year’s Nobel Prizes Are Straight Out Of Science Fiction

October 10, 2018 by Steven Dufresne 22 Comments

In the 1966 science fiction movie Fantastic Voyage, medical personnel are shrunken to the size of microbes to enter a scientist’s body to perform brain surgery. Due to the work of this year’s winners of the Nobel Prize in Physics, laser tools now do work at this scale.

Arthur Ashkin won for his development of optical tweezers that use a laser to grip and manipulate objects as small a molecule. And Gérard Mourou and Donna Strickland won for coming up with a way to produce ultra-short laser pulses at a high-intensity, used now for performing millions of corrective laser eye surgeries every year.

Here is a look at these inventions, their inventors, and the applications which made them important enough to win a Nobel.

Continue reading “This Year’s Nobel Prizes Are Straight Out Of Science Fiction” →

Laser Noob: Getting Started With The K40 Laser

September 27, 2018 by Adam Fabio 77 Comments

Why spend thousands on a laser cutter/engraver when you can spend as little as $350 shipped to your door? Sure it’s not as nice as those fancy domestic machines, but the plucky K40 is the little laser that can. Just head on down to Al’s Laser Emporium and pick one up. Yes, it sounds like a used car dealership ad, but how far is it from the truth? Read on to find out!

Laser cutting and engraving machines have been around for decades. Much like 3D printers, they were originally impossibly expensive for someone working at home. The closest you could get to a hobbyist laser was Epilog laser, which would still cost somewhere between $10,000 and $20,000 for a small laser system. A few companies made a go with the Epilog and did quite well – notably Adafruit used to offer laptop laser engraving services.

Over the last decade or so things have changed. China got involved, and suddenly there were cheap lasers on the market. Currently, there are several low-cost laser models available in various power levels. The most popular is the smallest – a 40-watt model, dubbed the K40. There are numerous manufacturers and there have been many versions over the years. They all look about the same though: A blue sheet metal box with the laser tube mounted along the back. The cutting compartment is on the left and the electronics are on the right. Earlier versions came with Moshidraw software and a parallel interface.

Continue reading “Laser Noob: Getting Started With The K40 Laser” →

DIY laser rifle doing damage long distance

DIY Long Distance Laser Telescope Does Some Damage

August 31, 2018 by Steven Dufresne 44 Comments

Here’s a DIY laser rifle which can explode a balloon at around 150 feet (45 meters) as well as some angry chemicals at a similar distance. Since there are plenty of videos of lasers doing that at around a meter, why shouldn’t doing so farther away be easy? Despite what many expect, laser beams don’t remain as straight lines forever. All light diverges over a distance. This makes it hard to create a laser which can do damage from more than around a meter and is why most demonstrations on YouTube are that distance or less.

[Styropyro’s] handheld, DIY laser rifle, or Laser Telescope Blaster as he calls it, works for long distances. His solution lies in some surprising physics: the larger the diameter of the beam, the more slowly it will diverge. So he used the opposite of a Galilean telescope to take the small beam of his 405-nanometer laser and increase its diameter. His best result was to explode a balloon at 150 feet (45 meters).

He did run into another issue first though. Anyone who’s tried to keep a camera aimed at a target through a telephoto lens while holding the camera in their hands knows that even a tiny movement will throw the camera off target. For a laser beam to sufficiently heat up the balloon in order to make it explode, the beam has to stay on it for a short period of time. But at a long distance, small movements of his rifle made the beam wander. Putting the rifle on a tripod fixed that. In the video below you can see him work through his design and these issues to finally get his big success.

We can guess what spurred on this interest in long-distance laser rifles. Back in July, a Chinese company made bold claims to building one which could do damage at 800 meters.

Continue reading “DIY Long Distance Laser Telescope Does Some Damage” →

Science Shows Green Lasers Might Be More Than You Bargained For

August 31, 2018 by Dan Maloney 54 Comments

This may come as a shock, but some of those hot screaming deals on China-sourced gadgets and goodies are not all they appear. After you plunk down your pittance and wait a few weeks for the package to arrive, you just might find that you didn’t get exactly what you thought you ordered. Or worse, you may get a product with unwanted ~~bugs~~ features, like some green lasers that also emit strongly in the infrared wavelengths.

Sure, getting a free death ray in addition to your green laser sounds like a bargain, but as [Brainiac75] points out, it actually represents a dangerous situation. He knows whereof he speaks, having done a thorough exploration of a wide range of cheap (and not so cheap) lasers in the video below. He explains that the paradox of an ostensibly monochromatic source emitting two distinct wavelengths comes from the IR laser at the heart of the diode-pumped solid state (DPSS) laser inside the pointer. The process is only about 48% efficient, meaning that IR leaks out along with the green light. The better quality DPSS laser pointers include a quality IR filter to remove it; cheaper ones often fail to include this essential safety feature. What wavelengths you’re working with are critical to protecting your eyes; indeed, the first viewer comment in the video is from someone who seared his retina with a cheap green laser while wearing goggles only meant to block the higher frequency light.

It’s a sobering lesson, but an apt one given the ubiquity of green lasers these days. Be safe out there; educate yourself on how lasers work and take a look at our guide to laser safety. Continue reading “Science Shows Green Lasers Might Be More Than You Bargained For” →