Flagging Down Aliens With World’s Biggest Laser Pointer

November 20, 2018 by Tom Nardi 86 Comments

As you’re no doubt aware, humans are a rather noisy species. Not just audibly, like in the case of somebody talking loudly when you’re in a movie theater, but also electromagnetically. All of our wireless transmissions since Marconi made his first spark gap broadcast in 1895 have radiated out into space, and anyone who’s got a sensitive enough ear pointed into our little corner of the Milky Way should have no trouble hearing us. Even if these extraterrestrial eavesdroppers wouldn’t be able to understand the content of our transmissions, the sheer volume of them would be enough to indicate that whatever is making all that noise on the third rock orbiting Sol can’t be a natural phenomena. In other words, one of the best ways to find intelligent life in the galaxy may just be to sit around and wait for them to hear us.

Of course, there’s some pesky physics involved that makes it a bit more complicated. Signals radiate from the Earth at the speed of light, which is like a brisk walk in interstellar terms. Depending on where these hypothetical listeners are located, the delay between when we broadcast something and when they receive it can be immense. For example, any intelligent beings that might be listening in on us from the closest known star, Proxima Centauri, are only just now being utterly disappointed by the finale for “How I Met Your Mother“. Comparatively, “Dallas” fans from Zeta Reticuli are still on the edge of their seats waiting to find out who shot J.R.

But rather than relying on our normal broadcasts to do the talking for us, a recent paper in The Astrophysical Journal makes the case that we should go one better. Written by James R. Clark and Kerri Cahoy, “Optical Detection of Lasers with Near-term Technology at Interstellar Distances” makes the case that we could use current or near-term laser technology to broadcast a highly directional beacon to potentially life-harboring star systems. What’s more, it even theorizes it would be possible to establish direct communications with an alien intelligence simply by modulating the beam.

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The Electric Imp Sniffs Out California Wildfires

November 20, 2018 by Tom Nardi 13 Comments

The wildfires in California are now officially the largest the state has ever seen. Over 50,000 people have been displaced from their homes, hundreds are missing, and the cost in property damage will surely be measured in the billions of dollars when all is said and done. With a disaster of this scale just the immediate effects are difficult to conceptualize, to say nothing of the collateral damage.

While not suggesting their situation is comparable to those who’ve lost their homes or families, Electric Imp CEO [Hugo Fiennes] has recently made a post on their blog calling attention to the air quality issues they’re seeing at their offices in Los Altos. To quantify the problem so that employees with respiratory issues would know the conditions before they came into work, they quickly hacked together a method for displaying particulate counts in their Slack server.

The key to the system is one of the laser particle sensors that we’re starting to see more of thanks to a fairly recent price drop on the technology. A small fan pulls air to be tested into the device, where a very sensitive optical sensor detects the light reflected by particles as they pass through the laser beam. The device reports not only how many particles are passing through it, but how large they are. The version of the sensor [Hugo] links to in his blog post includes an adapter board to make it easier to connect to your favorite microcontroller, but we’ve previously seen DIY builds which accomplish the same goal.

[Hugo] then goes on to provide firmware for the Electric Imp board that reads the current particulate counts from the sensor and creates a simple web page that can be viewed from anywhere in the world to see real-time conditions at the office. From there, this data can be plugged into a Slack webhook which will provide an instantaneous air quality reading anytime a user types “air” into the channel.

We’ve covered a number of air quality sensors over the years, and it doesn’t look like they’re going to become any less prevalent as time goes on. If anything, we’re seeing a trend towards networks of distributed pollution sensors so that citizens can collect their own data on their air they’re breathing.

[Thanks to DillonMCU for the tip.]

Fail Of The Week: Laser-based Persistence Of Vision Gadget

November 18, 2018 by Donald Papp 37 Comments

[XTronical]’s idea for a laser-based persistence of vision gadget failed, but the basic idea seemed sound. A row of inexpensive red lasers shine into a spinning mirror and are reflected onto a distant surface, making 8 scan lines. A reflective object sensor detects mirror position, and by rapidly turning individual lasers on and off, a pattern can be drawn out.

That was the idea, anyway. A quick prototype consisting of some small and economical red laser diodes and a double-sided mirror hot glued to the shaft of a small DC motor formed the guts of the unit. [XTronical] worried that the spinning mirror might be unstable or unreliable, but that part performed just fine. The problems, he found, were mainly with the lasers.

[XTronical] had hoped to turn the lasers on and off directly via the digital I/O pins of an Arduino, but here’s where a lot of little issues sank the project. First of all, hot glue was handy for mounting but the lasers were cumbersome to align by hand, and the hot glue made it troublesome to effect repairs when units failed. In addition, the beams had inconsistent brightness and spot sizes, which made for poor visuals. [XTronical]’s approach of controlling the lasers by applying and cutting power may also have been a source of trouble. It’s possible that these lasers cannot turn on and off fast enough, but it’s hard to say without measuring.

Sensible ideas can be rendered unworkable by an accumulation of small problems, and that seems to have been the case here. A video overview is embedded below; is this approach doomed, or can it be made workable?

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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.

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Laser Cutter Resurrection Uncovers A Magnificent Machine Beneath The Ash

October 19, 2018 by Sonya Vasquez 32 Comments

Trash is relative. When my coworker accidentally lit an ABS-barbecue inside the company laser cutter, he made trash. The wreckage was headed for the dump, but I managed to save it and pass it on to my friend [Amy]. Four months later, she phoenixed it back to life from the trash-it-was to a glorious new system more powerful than the original. This is her story, carefully told in detail in a three-part series (part one, part two, part three) that takes us on a journey from trash to triumph. She even recorded video of the entire process (also embedded below)

Get your notes out because while [Amy] spares every expense to keep this project cheap, she spares no expense at laying out the details for anyone’s path to success when working with these beasts.

As far as origin stories go, our story starts at my last employer’s office. I was in the machine shop asking one of our MechEs a question when the intern points a finger towards the corner of the room and asks: “hey is that supposed to be on fire?” I turn around to see billowing flames coming from our budget Chinese laser cutter. “Nope!” I say. “We need a fire extinguisher!” But our MechE was already on it. In half a moment he returned with an extinguisher. With one squirt the fire was out, but the machine was caked with a nasty powdery debris. It turns out another coworker had committed the almighty sin of laser cutting: he turned it on and walked away. Better yet, it was cutting ABS with a disconnected air nozzle.

This cutter was headed to the dump, but a few shenanigans later, I managed to divert this heap to [Amy]. The paint job was an absolute disaster on the outside, and the gooey ABS-and-powder mixture had caked over the inside. [Amy] dug in, stripping off the paint flakes and re-coating it. Apart from the belts, she salvaged every other part inside the machine. Her secret: “IPA and steel wool.” From there, she built her own fume extractor and lofted the whole system onto a frame she welded herself so that she could push both extractor and cutter around her wood shop as a unit. These days, it’s seeing some mileage for cutting out jigs for her woodworking projects.

Perhaps what’s truly special about this project is that she restored it with the camera rolling. As if building projects isn’t hard enough, getting the right lighting and camera angles while you’re doing the work is even more work! There’s no drop-down lofted camera setup in her garage, so each documented step is carefully set up so it captures what’s happening onscreen. While the IPA-and-steel wool might’ve been one nifty trick, by the end of these videos you’ll find that there really aren’t any secrets: just one engineer who sees the dignity in a project done well and has the patience to carry it out.

Get to know [Amy] on her blog, and you’ll discover the true finesse of her scavenging and engineering wielded hand-in-hand. From Ukuleles borne of fallen tree branches to a garage woodshop bootstrapped from a series of Craigslist adventures, it’s no surprise that a broken laser cutter would find a new life when it landed in her hands.

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Video Shows Power Isn’t Everything In Laser Engraving

October 11, 2018 by Donald Papp 22 Comments

When it comes to power tools, generally speaking more watts is better. But as laser maestro [Martin Raynsford] shows, watts aren’t everything. He shares a brief video showing his older 100 W laser being handily outperformed by a newer 30 W machine. Shouldn’t the higher power laser be able to do the same job in less time? One might think so, but wattage isn’t everything. The 30 W laser engraves and cuts a wooden tile in just under half the time it takes the 100 W machine to do the same job, and with a nicer end result, to boot.

Why such a difference? Part of the answer to that question lies in that the newer machine has better motion control and can handle higher speeds, but the rest is due to the tubes themselves. The older 100 W machine uses a DC-excited (big glass water-cooled tube) CO2 laser, and the newer 30 W machine uses an RF-excited laser that looks a bit like a big metal heat sink instead of oversized lab glassware. Both tubes output what is essentially the same beam, but the RF tube is overall capable of a more refined, more stable, and more finely focused point than that of the glass tube. Since engraving uses only a small fraction of even the 30 W laser’s power, the finer control that the RF laser has over the low end of the power scale results in a much higher quality engraving.

Embedded below is a short video showing both machines engraving and cutting the same tile, side by side. You may wish to consider watching this one full screen, to better see the fine details.

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