Laser-Based Audio Injection On Voice-Controllable Systems

November 6, 2019 by Pat Whetman 27 Comments

In one of the cooler hacks we’ve seen recently, a bunch of hacking academics at the University of Michigan researched the ability to flicker a laser at audible sound frequencies to see if they could remotely operate microphones simply by shining a light on them. The results are outstanding.

While most Hackers will have heard about ‘The Thing’ – a famous hack where Russian KGB agents would aim a radio transmitter at the great seal in the US embassy, almost none of us will have thought of using lasers shined in from distant locations to hack modern audio devices such as Alexa or Google Assistant. In the name of due diligence, we checked it out on Wikipedia: ‘The Photoacoustic Effect’ , and indeed it is real – first discovered in 1880 by Alexander Bell! The pulsing light is heating the microphone element and causing it to vibrate along with the beam’s intensity. Getting long range out of such a system is a non-trivial product of telescopes, lasers, and careful alignment, but it can be made to work.

Digging deeper into the hack, we find that the actual microphone that is vulnerable is the MEMS type, such as the Knowles SPV0842LR5H. This attack is relatively easy to prevent; manufacturers would simply need to install screens to prevent light from hitting the microphones. For devices already installed in our homes, we recommend either putting a cardboard box over them or moving them away from windows where unscrupulous neighbors or KGB agents could gain access. This does make us wonder if MEMS mics are also vulnerable to radio waves.

As far as mobile phones are concerned, the researchers were able to talk into an iPhone XR at 10 metres, which means that, very possibly, anybody with a hand held ultra violet / infra red equipped flashlight could hack our phones at close range in a bar, for example. The counter-measures are simple – just stick some black electrical tape over the microphone port at the bottom of the phone. Or stay out of those dodgy bars. Continue reading “Laser-Based Audio Injection On Voice-Controllable Systems” →

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.

Continue reading “Flagging Down Aliens With World’s Biggest Laser Pointer” →

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.

Continue reading “Laser Cutter Resurrection Uncovers A Magnificent Machine Beneath The Ash” →

Robert Hall And The Solid-State Laser

May 22, 2018 by Dan Maloney 13 Comments

The debt we all owe must be paid someday, and for inventor Robert N. Hall, that debt came due in 2016 at the ripe age of 96. Robert Hall’s passing went all but unnoticed by everyone but his family and a few close colleagues at General Electric’s Schenectady, New York research lab, where Hall spent his remarkable career.

That someone who lives for 96% of a century would outlive most of the people he had ever known is not surprising, but what’s more surprising is that more notice of his life and legacy wasn’t taken. Without his efforts, so many of the tools of modern life that we take for granted would not have come to pass, or would have been delayed. His main contribution started with a simple but seemingly outrageous idea — making a solid-state laser. But he ended up making so many more contributions that it’s worth a look at what he accomplished over his long career.

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Review: NEJE DK-8-KZ Laser Engraver

March 1, 2018 by Tom Nardi 100 Comments

When I got my first 3D printer I was excited, but now that I’m contemplating adding a forth to my collection, I have to come to the terms with the fact that these machines have all the novelty of a screwdriver at this point. Which is fine; getting the cost down and availability up is the key to turning a niche piece of technology into a mainstream tool, and the more people with 3D printers at home or in their workshop the better, as far as I’m concerned. But still, there’s a certain thrill in exploring the cutting edge, and I’ve been looking for something new to get excited about as of late.

Lasers seem like an interesting next step in my quest towards complete in-house fabrication capability, so I started researching cheap setups to get my feet wet. In the course of looking up diode-powered laser cutters, I came across the NEJE DK-8-KZ. At only 1W, there’s no question this device isn’t going to be cutting a whole lot. In fact, it’s specifically sold as an engraver. But given the fact that you can get one of these little guys for around $70 USD shipped, it’s hard to complain.

Now I wasn’t 100% sure what I would do with a laser engraver, but I thought it would be a good way to test the waters before putting serious money (and time) into something more powerful. Plus, if I’m being totally honest, I wanted to start on something on the lower end of the power spectrum because I’m terrified of blinding myself.

So what kind of laser do you get for $70? Let’s find out… Continue reading “Review: NEJE DK-8-KZ Laser Engraver” →

A Few Laser-Cut Cases For Your SBCs

February 4, 2018 by Jenny List 17 Comments

Single-board computers, usually featuring ARM processors, have revolutionized the world of the hardware hacker over the last decade. The computing power you would have found in a desktop computer not so long ago, mounted on a small PCB and powered from a mobile phone charger.

With a few notable exceptions though, these single board computers are just that, boards. No cases in the pack, which has, of course, spawned a huge aftermarket of commercial offerings and a pile of homemade ones of varying sophistication. If these homemade offerings are your fancy then today’s link may be of interest, some very well-designed laser-cut cases from [Nick Smith] for a selection of popular and less well-known boards.

The Orange Pi Lite and Raspberry Pi Zero are both familiar enough, but one of the delights of writing for Hackaday reveals itself in the discovery of the more esoteric Marvell ESPRESSObin, an SBC with multiple network ports and serial ATA.

Are cases your passion? Step back in time for our round-up of case designs for the first Raspberry Pi.

Via Hacker News.

Teardown: What’s Inside A Christmas Laser Projector?

January 22, 2018 by Tom Nardi 55 Comments

In the world of big-box retail, December 26th is a very special day. The Christmas music playing on the overhead speakers switches back to the family friendly Top 40, the store’s decorations get tossed in the compactor, and everything that’s even remotely related to the holiday is put on steep clearance. No more money to be made on the most commercialized of all holidays, so back to business as usual.

It’s in this narrow corridor of time, between the Great Holiday Unloading and the new spring products coming in, that you can find some fantastic deals on Christmas decorations. Not that long ago, this would hardly be exciting news for the readers of Hackaday. But Christmas lights and decorations have really started pushing the envelope in terms of technology: addressable RGB LED strands, Bluetooth controlled effects, and as of the last couple years, friggin’ lasers.

That’s right, you’ve seen them all over the neighborhood, probably took a few stray beams to the eye, you might even own your own. Laser projectors have been one of the most popular Christmas decorations for the last couple of years, and it’s not hard to see why. Just set the projector up in front of your house, and you’re done. No need to get on a ladder and string lights on the roof when you can just blast some directed energy up there instead.

Given how popular they are, I was surprised to see a lone Home Accents Holiday Multi-Color Light Projector on the clearance rack at Home Depot for around $14 a few days after Christmas. This was a 75% price reduction from normal MSRP, and right in that sweet impulse-buy price range. Let’s see what’s hiding inside!

Continue reading “Teardown: What’s Inside A Christmas Laser Projector?” →