Bone Conduction Skull Radio

August 17, 2016 by Jenny List 20 Comments

There are many ways to take an electrical audio signal and turn it into something you can hear. Moving coil speakers, plasma domes, electrostatic speakers, piezo horns, the list goes on. Last week at the Electromagnetic Field festival in the UK, we encountered another we hadn’t experienced directly before. Bite on a brass rod (sheathed in a drinking straw for hygiene), hear music.

This was Skull Radio, a bone conduction speaker courtesy of [Tdr], one of our friends from TOG hackerspace in Dublin, and its simplicity hid a rather surprising performance. A small DC motor has its shaft connected to a piece of rod, and a small audio power amplifier drives the motor. Nothing is audible until you bite on the rod, and then you can hear the music. The bones of your skull are conducting it directly to your inner ear, without an airborne sound wave in sight.

The resulting experience is a sonic cathedral from lips of etherial sibilance, a wider soft palate soundstage broadened by a tongue of bass and masticated by a driving treble overlaid with a toothy resonance before spitting out a dynamic oral texture. You’ll go back to your hi-fi after listening to [Tdr]’s Skull Radio, but you’ll know you’ll never equal its unique sound.

(If you are not the kind of audiophile who spends $1000 on a USB cable, the last paragraph means you bite on it, you hear music, and it sounds not quite as bad as you might expect.)

This isn’t the first bone conduction project we’ve featured here, we’ve seen a Bluetooth speaker and at least one set of headphones, but our favorite is probably this covert radio.

Hackaday Prize Entry: Grasshopper Neurons

August 16, 2016 by Brian Benchoff 4 Comments

A plague of locusts descends on your garden, and suddenly you realize grasshoppers are very hard to catch. Grasshoppers are nature’s perfect collision avoidance system, and this is due to a unique visual system that includes neurons extending directly from the eye to the animal’s legs. For this Hackaday Prize entry – and as a research project for this summer at Backyard Brains, [Dieu My Nguyen] is studying the neuroscience of grasshopper vision with stabs and shocks.

We visited Backyard Brains about two years ago, and found three very interesting projects. The first was a project on optogenetics, or rewiring neurons so flies taste something sweet when they’re exposed to red light. The second was remote-controlled cockroaches. Number three will shock you: a device that allowed me to expand my megalomania by shocking people with the power of my mind. It’s not all fun and games, though. This grasshopper neuron probe will use the Backyard Brains SpikerBox to investigate when those neurons are activated in response to a stimuli.

The utility of looking at the common grasshopper to learn about collision and object avoidance may not be very apparent at first. The more you learn about neuroscience, the more apparent the biological connection to common computer vision tasks becomes. That makes this a great research project and an excellent entry into the Hackaday Prize.

16-channel Sampler Tests Arcade Buttons With Style

August 16, 2016 by Dan Maloney 6 Comments

The goal is simple: test a bunch of arcade buttons from different manufacturers to get the one with the best function and feel. The resulting build is anything but simple: this wonderfully over-designed 16-channel WAV sampler and mixer.

For those wondering why [Atarity] would go to this much trouble to test arcade buttons, we suspect an ulterior motive – skip to the 21:14 mark of the long video below to see the real design inspiration. Regardless of the motive, there’s no doubting the care that went into the build – CNC-milled birch case, extremely detailed laser-engraved graphics, and a carbon-fiber back plate covered with suede, because suede. We especially like the detail on the speaker grill: the embroidered fabric and puffed-up look really works with the rest of the design, including the leather hand strap.

It’s not entirely clear from the post what the end goal of the testing is, but we assume it’ll be some sort of MAME build. In which case, [Atarity] might want to check out our recent articles on a tabletop MAME cabinet or this portable MAME rig. But whatever he comes up with, we’re sure the craftsmanship will be there.

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Fail Of The Week: How NOT To Smooth A 3D Print

August 16, 2016 by Dan Maloney 78 Comments

Many of the Fail Of The Week stories we feature here are pretty minor in the grand scheme of things. At worse, gears are ground, bits are broken, or the Magic Blue Smoke is released. This attempt to smooth a 3D print released far more than a puff of blue smoke, and was nearly a disaster of insurance adjuster or medical examiner proportions.

Luckily, [Maxloader] and his wife escaped serious injury, and their house came out mostly unscathed. The misadventure started with a 3D printed Mario statue. [Maxloader] had read acetone vapor can smooth a 3D print, and that warming the acetone speeds the process. Fortunately, his wife saw the looming danger and wisely suggested keeping a fire blanket handy, because [Max] decided to speed the process even more by putting a lid on the pot. It’s not clear exactly what happened in the pot – did the trapped acetone vapors burp the lid off and find a path to the cooktop burner? Whatever it was, the results were pretty spectacular and were captured on a security camera. The action starts at 1:13 in the video below. The fire blanket came in handy, buying [Max] a few seconds to open the window and send the whole flaming mess outside. Crisis averted, except for nearly setting the yard on fire.

What are we to learn from [Maxloader]’s nearly epic fail? First, acetone and open flame do not mix. If you want to heat acetone, do it outside and use an electric heat source. Second, a fire extinguisher is standard household equipment. Every house needs at least one, and doubly so when there’s a 3D printer present. And third, it’s best to know your filaments – the dearly departed Mario print was in PLA, which is best smoothed with tetrahydrofuran, not acetone.

Anything else? Feel free to flame away in the comments.

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A Tech That Didn’t Make It: Sound On Stainless Steel Wire

August 16, 2016 by Gerrit Coetzee 61 Comments

For a brief period in the 1940’s it might have been possible for a young enamored soul to hand his hopeful a romantic mix-spool of wire. This was right before the magnetic tape recorder and its derivatives came into full swing and dominated the industry thoroughly until the advent of the compact disk and under a hundred kilogram hard disk drives. [Techmoan] tells us all about it in this video.

The device works as one would expect, but it still sounds a little crazy. Take a ridiculously long spool of steel wire the size of a human hair(a 1 hour spool was 2.2km of wire), wind that through a recording head at high speed, magnetize the wire, and spool it onto a receiving spool.

If you’re really lucky the wire won’t dramatically break causing an irreversible tangle of wire. At that point you can reverse the process and hear the recorded sound. As [Techmoan] shows, the sound can best be described as… almost okay. Considering that its chief competition at the time was sound carved into expensive aluminum acetate plates, this wasn’t the worst.

The wire recorder lived on for a few more years in niche applications such as airplane black boxes. It finally died, but it does sound like a really fun couple-of-weekends project to try and build one. Make sure and take good pictures and send it in if any of you do.

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Creating Unbeatable Videogame AI

August 16, 2016 by Brian Benchoff 21 Comments

Super Smash Bros. Melee is a multiplayer fighting game released for the Nintendo GameCube in 2001. For the last decade and a half, it has become one of the premier fighting game eSports, and it is the reason Nintendo still makes a GameCube controller for the Wii U. Smash Melee has an intense following, and for years the idea of an AI that could beat top-tier players at Melee was inconceivable – the game was just far too complex, the strategies too demanding, and the tactics too hard.

[Dan] a.k.a. [AltF4] wasn’t satisfied that a computer couldn’t beat players at Melee, and a few years ago started work on the first Melee AI that could beat any human player. He just released Smashbot at this year’s DEF CON, and while the AI is limited, no human can beat this AI.

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Retrotechtacular: Tom Carter Revolutionized Your Phone

August 16, 2016 by Al Williams 39 Comments

It is hard to remember, but there was a time when you couldn’t hook much to a telephone line except a telephone. Although landlines are slowly falling out of favor, you can still get corded and wireless phones, answering machines, and even dial up modems. Alarm systems sometimes connect to the phone system along with medical monitoring devices and a host of other accessories.

All of that’s possible because of a Texan named Tom Carter. Tom Carter was the David that stood up to one of the biggest Goliath’s of his day: the phone company. The phone company had a legal monopoly on providing phone service. The reasoning was that it didn’t make sense to have multiple competing companies trying to run wires to every house and business in the country. Makes sense, right?

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